A Survey of Mosquitoes Along the Murray River in South Australia

2016-17 Prepared by S.R. Fricker, & C.R. Williams Healthy Environments, Healthy People Research Group Sansom Research Institute School of Pharmacy & Medical Sciences The University of South Australia GPO Box 2471 Adelaide SA 5000

A survey of mosquitoes along the Murray River in South Australia.

A REPORT PREPARED FOR Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council.

Mosquito surveillance along the River Murray in South Australia was conducted from late August 2016 to April 2017. Overall, a total of 59, 777 (n=353) adult female mosquitoes were collected from 35 regular monitoring sites. The mosquito populations along the River Murray all exhibited a distinct early spring cohort, consisting of predominantly the early season mosquito Ae. camptorhynchus in the south, and a mixture of Cx. australicus, An. annulipes, Ae. camptorhynchus and Cx. annulirostris in the more northerly monitoring points.

A survey of mosquitoes along the Murray River in South Australia 2016-17.

Prepared by S.R. Fricker, & C.R. Williams Healthy Environments, Healthy People Research Group Sansom Research Institute School of Pharmacy & Medical Sciences Frount page picture of Mundic Creek Rd December 2016

CONTENTS

CONTENTS ...... 0 1. SUMMARY...... 4 Mosquito-borne disease...... 5 2. INTRODUCTION...... 7 3. METHODS...... 9 Adult trap location and monitoring procedures...... 9 Larval site locations and monitoring procedures...... 11 Weather Data...... 11 River Flow Data...... 12 Arbovirus infection notification data...... 13 Arbovirus detection project-passive traps/FTA cards...... 13 4. GENERAL RESULTS AND INFORMATION FOR ALL COUNCILS...... 15 Arbovirus infection data 2016-2017...... 15 Arbovirus detection project-passive traps/FTA cards...... 20 River Levels...... 21 5. RESULTS FOR THE RENMARK PARINGA COUNCIL...... 24 Adult trap site descriptions...... 24 Weather Data: Renmark Paringa Council...... 27 Adult mosquito trapping results: Renmark Paringa Council...... 31 Mosquito Larval Dipping and Treatment: Renmark Paringa Council...... 35 Discussion of Renmark Paringa results...... 39 COMMENTS...... 45 LOCAL RECOMMENDATIONS...... 47 6. RESULTS FOR THE BERRI BARMERA COUNCIL...... 48 Adult trap site descriptions...... 48 Weather Data: Berri Barmera Council...... 51 Adult mosquito trapping results: Berri Barmera Council...... 53 Mosquito Larval Dipping and Treatment: Berri Barmera Council ...... 57 Discussion of Berri Barmera results...... 60 COMMENTS...... 65

CONTENTS LOCAL RECOMMENDATIONS...... 67 7. RESULTS FOR THE DISTRICT COUNCIL OF LOXTON WAIKERIE...... 68 Adult trap site Descriptions...... 68 Weather Data: The District Council of Loxton Waikerie...... 71 Adult mosquito trapping results: The District Council of Loxton Waikerie...... 75 Mosquito Larval Dipping and Treatment: Loxton Waikerie Council...... 79 Discussion of Loxton Waikerie Results...... 81 COMMENTS...... 85 LOCAL RECOMMENDATIONS...... 87 8. RESULTS FOR THE MID-MURRAY COUNCIL...... 88 Adult trap site descriptions...... 88 Weather Data: Mid-Murray Council...... 91 Adult mosquito trapping results: Mid-Murray Council...... 94 Mosquito Larval Dipping and Treatment: Mid-Murray Council...... 98 Discussion of Mid-Murray Results...... 100 COMMENTS...... 104 LOCAL RECOMMENDATIONS...... 106 9. RESULTS FOR THE RURAL CITY OF MURRAY BRIDGE...... 107 Adult trap site descriptions...... 107 Weather Data: The Rural City of Murray Bridge...... 110 Adult mosquito trapping results: The Rural City of Murray Bridge...... 114 Mosquito Larval Dipping and Treatment: The Rural City of Murray Bridge...... 118 Discussion of Murray Bridge Results...... 121 COMMENTS...... 125 LOCAL RECOMMENDATIONS...... 127 10. RESULTS FOR THE COORONG DISTRICT COUNCIL...... 128 Adult trap site descriptions...... 128 Weather Data: The Coorong District Council...... 131 Adult mosquito trapping results: The Coorong District Council...... 135 Mosquito Larval Dipping and Treatment: The Coorong District Council...... 139 Discussion of Coorong Council results...... 141 COMMENTS...... 145 LOCAL RECOMMENDATIONS...... 147 11. RESULTS FOR THE ALEXANDRINA COUNCIL...... 148 Adult trap site descriptions...... 148

1 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. CONTENTS Weather Data: Alexandrina Council...... 151 Adult mosquito trapping results: The Alexandrina Council...... 152 Mosquito Larval Dipping and Treatment: Alexandrina Council...... 156 Discussion of Alexandrina Council results...... 158 COMMENTS...... 162 LOCAL RECOMMENDATIONS...... 164 12. GENERAL DISCUSSION...... 165 13. GENERAL RECOMMENDATIONS...... 174 14. REFERENCES...... 175 15. ONLINE RESOURCES...... 176 APPENDIX 16 List of abbreviations ...... 177 APPENDIX 17: An abridged guide to mosquito of medical importance in South Australia...... 178

2 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

3 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

1. SUMMARY.

The Healthy Environments, Healthy People Research Group at the University of South Australia (UniSA) provided mosquito surveillance and spot control services to seven local government areas along the River Murray in South Australia (SA), from late August 2016 to April 2017. This was the eighteenth consecutive year of this service for six of the local councils and the sixth consecutive season Alexandrina Council has participated in the program. Eleven sampling periods were undertaken by the field officer (Stephen Fricker) for each adult mosquito trap (EVS) location. Regular reports to local Environmental Health Officers and the South Australian Department of Health were also produced in the form of the SA mosquito intelligence report the “SAMIR report” along with post sampling data reports and periodic informal updates. Data from mosquito traps along the River Murray during the 2016/17 season generally featured seasonally high numbers during spring to early summer. This was due to high numbers of the cool weather Aedes species Ae. camptorhynchus collected in the southern reaches of the river and a mixture of Cx. australicus, An. annulipes, Ae. camptorhynchus and Cx. annulirostris at more northerly locations. The previous two seasons featured a return of the spring species Ae. camptorhynchus as an important component of the mosquito community along the length of the river. This season Ae. camptorhynchus was again collected in high numbers at some locations in the upper river demonstrating that it is now re-established. Preseason treatment may require more attention in northern councils in order to alleviate the risk associated with Ae. camptorhynchus mosquitoes over spring. Spring rains, cool weather and an unregulated flow event along the River Murray produced uncertain conditions over late 2016. The cool weather Culex species Cx. australicus proliferated over spring causing much concern amongst residents. Although this species itself is not of human health concern, it utilises similar larvae habitats to the major vector species Cx. annulirostris which requires warmer conditions in order to thrive. As a precaution larvae sites of Cx. australicus were identified and treated along with Ae. camptorhynchus over the spring period. The Mid Murray, the Rural City of Murray Bridge and Alexandrina Councils all recorded increased numbers of mosquitoes over the early summer period. This was due to a mixture of species including the cool weather mosquito Ae. camptorhynchus, and An. annulipes. The individual circumstances are discussed in the chapters relevant to each council. However, the mosquito species Cq. linealis is an ongoing issue along the river where it is locally abundant. It is problematic to control due to the nature of the larvae habitats it exploits. The unregulated flow event along the River Murray reached its zenith in late December 2016 and was also reflected in an increase in the

4 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 1 Summary level of the lower lakes shortly after. The following month some of the highest catches of Ae. camptorhynchus were recorded around trap sites adjacent the lakes Overall a total of 59, 777 (n=353) adult female mosquitoes were collected from 35 regular monitoring sites over the 2016-17 season. The use of regular monitoring sites provides information about the diversity and abundance of mosquitoes along the River Murray and allows comparisons between years at these sites. The total number of adult female mosquitoes caught this season was three times the previous season's total mosquito catch; however, this increase was not uniform across all councils. In the Mid-Murray and the three northernmost councils, the total number of female mosquitoes caught were, between 6.5 to 39 times the previous season's total mosquito catch (corrected for n=55). In contrast, the lower river (The Rural City of Murray Bridge) and lower lakes all recorded only a modest change in the previous season. This ranged from an increase of around 4.8 times the previous season in the Coorong District Council to a halving within Alexandrina Council. Throughout the study area, seasonal and regional trends were detected, mosquitoes were identified, and in some instances controlled at their source.

Mosquito-borne disease.

During the 2016-17 season, the Department of Health (SA) was notified of 528 cases of indigenous arboviral infection occurring in South Australia [525 cases of Ross River virus infection (RRV) 430 probable and 95 confirmed, 3 cases of Barmah Forest virus (BFV) 2 probable and 1 confirmed]. The Riverlands’ and lower lakes can be linked to 238 cases of RRV (200 probable and 38 confirmed) and one probable case of BFV. The number of reported notifications across South Australia was higher than in the previous season (79 RRV [28 River Murray Communities], 3 BFV [2 River Murray Communities]). During the 2016-17 season, there were a number of cases of exotic arboviral infection imported into South Australia including 89 cases of dengue Fever, eight cases of chikungunya virus (CHIKV) and nine the parasitic infection malaria. No imported cases of Japanese encephalitis or Zika virus were reported during the period. The importation of dengue Fever currently poses a minimal public health risk due to the absence of any recognised potential vectors of this disease. A number of repeated incursions of dengue vectors at Southern Australian airports (including Adelaide Airport) have occurred over recent years. Currently, South Australia remains free of established viable populations of these species. The continued occurrence of imported cases of CHIKV has ben of some concern as van den Hurk, Hall-Mendelin [1] demonstrated that a number of Australian Aedes species are

5 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 1 Summary competent laboratory vectors of CHIKV. However further research has indicated that although physiologically capable, are not likely to be vectors of CHIKV. Due to the success of the new virus detection technologies (FTA cards) trialled in 2013-14 these FTA cards were again incorporated into the current season’s regular adult sampling program. As part of our regular sampling program during the current season, we inserted honey baited “FTA Cards” into two EVS traps of the five set in each council. Traps to be fitted with FTA cards were chosen on the basis of the likelihood of high mosquito numbers and the mix of vectors commonly caught at trap sites. In December 2016, there was a detection of RRV in an EVS trap located at Wellington Caravan Park (MB1). In response, arbovirus surveillance was increased with FTA cards set in additional EVS traps while mosquito populations remained high. This resulted in further detections of arbovirus in the lower sections of the river.

In addition to this program, four passive CO2 baited traps were also deployed by the Healthy Environments, Healthy People Research Group and FTA cards exposed on four occasions (16 cards). Two of these traps were sites adjacent sentinel chicken flocks located in the Riverland (The Rural City of Murray Bridge) and lower lakes (Meningie). The remaining two were located in alternate locations (Renmark and Loxton). Each trap contained a honey baited “FTA Card” and remained in situ for over three to four weeks. This work was conducted directly for the Department of Health and is included in this report for both interest and completeness. The 'virus detection' of all FTA cards was undertaken by the Arbovirus Reference Laboratory in NSW. An additional passive trap was set at adjacent the sentinel flock at Qualco, unfortunately, this trap had a number of technical issues with the regulator and timer and was eventually abandoned.

6 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

2. INTRODUCTION.

The mosquito surveillance and spot control program along the River Murray has now been carried out for eighteen consecutive years, originally commissioned by six local governments: Renmark Paringa, Berri Barmera, Loxton Waikerie, Mid-Murray, Murray Bridge and Coorong. Alexandrina Council joined the program in the 2011-12 Season, providing a complete picture of the mosquito communities along the river from the South Australian and Victorian-NSW border through to the coast. There are both short- and long-term benefits to the communities along the river of long-term monitoring as follows: • Mosquito larvae sites are identified, their location recorded and catalogued, enabling control to either be carried out immediately, or recommendations made for engineering works to prevent further breeding. This includes the detection of new mosquito breeding sites throughout the season. • Mosquito abundance is closely monitored, allowing environmental health officers to gauge the level of disease risk and a nuisance to the community. • The level of public awareness about mosquito nuisance and disease problems is raised. • Environmental Health Officers are able to monitor mosquito dynamics in their area in the context of adjoining areas and the River Murray in SA as a whole, from the border to the coast. This permits information sharing, the identification of common goals and implementation of strategies throughout the region, this is further enhanced with the production of SA mosquito intelligence report SAMIR. • A long-term data set has been created, allowing significant seasonal and regional trends to be identified, giving the local government, scientists and health workers a perspective of the River Murray, not as a series of segments each governed by a separate council, but as an ecological continuum. • Exotic mosquito species newly introduced into Australia can be monitored, such as Cx. gelidus and Ae. albopictus, both of which are important disease vectors. • The influence of climate variation on mosquito communities can be detected. • The mosquito data set created by this work has facilitated the development of a predictive model (RR Forecaster) in 2007 to enable better planning and management of mosquito disease problem risk. Further surveillance allows predictions to be made using RR Forecaster and refinement of the predictive models. The following year 2008 saw the expansion of the RR Forecaster to include nuisance mosquitoes.

7 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 2. Introduction

Front Screen of RR Forecaster software (Ver. 2.1) developed using long-term mosquito surveillance data A peer-reviewed article, Williams et al [2], utilises the data generated by this program to describe how environment and mosquito abundance influences Ross River virus activity along the river: Overall, this program makes both immediate and long-term contributions to practical public health and scientific research along the River Murray. In this report, we detail the results and analyses of mosquito monitoring along the River Murray in SA between August 2016 and May 2017. In order to provide data that are comparable from year to year, the same sampling sites and methods used in previous surveys have been retained. Outlines of methods used and the descriptions of adult trapping and larval monitoring sites have been included in this report.

8 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

3. METHODS.

Adult trap location and monitoring procedures. For the 2016-2017 trapping season, 35 adult trap sites were operated along the length of the River Murray. Five trap sites were chosen within each council area at locations selected by the local Environmental Health Officer or by UniSA staff, based on the prevalence of complaints or proximity to population centres.

At each site, a single CO2 baited light trap (EVS type) was set 0.5 - 1 m from the ground. Trap sites were identified by a code with a letter/s indicating the council area and the number (1 to 5), indicating its position along the river; Site 1, was the site furthest upstream and Site 5, the furthest downstream. For example, MM3 was the third EVS trap downstream in the Mid-Murray Council Area. Maps and satellite images (from Google Earth) of each adult trap site are supplied at the beginning of each chapter considering each separate local Council. An overview of the whole program is illustrated in Figure 3.1. The area covered by this survey is quite extensive and the landscape diverse. In previous years, the six council areas involved in long-term monitoring were placed into three groupings based on physical similarities of landscape and land use. Arbovirus modelling has indicated that not all three groupings hold true. The results of this investigation are discussed in Williams et. al[2], the modelling supports the grouping of the three upper river councils consisting of Renmark Paringa, Berri Barmera and Loxton Waikerie local councils, comprise a single unit while the Mid Murray Council and Rural City of Murray Bridge Council are similar to each other and considered as the second unit. The Coorong Council was considered distinct from all other councils and as such considered on its own. With Alexandrina Council only joining the program in 2011, a detailed analysis of the relationship of this council with the others is yet to be conducted. The map overleaf illustrates the coverage of the River Murray by adult mosquito traps in SA. Each surveillance event was conducted over a single night, with traps being set in the afternoon and collected the following day. There were 11 sampling trips lasting several days, at 3- 4 week intervals from September to May. Adult catches were transported to the laboratory for sorting and identification using the keys and illustrations within “Mosquitoes and Mosquito-borne Disease in South-eastern Australia” by Russell [3], and “The Mosquitoes of Victoria” by N. V. Dobrotworsky [4]. Raw adult trap data is provided for each Council in Appendices 2-8, and summaries of adult mosquito trap data are presented in each relevant chapter.

9 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 3. Methods. Figure 3.1. Adult trap site locations.

Image from Google Earth RENMARK PARINGA MID-MURRAY ALEXANDRINA R1 Chaffey Irrigation Area MM1 Morgan Ferry A1 Milang R2 Riverfront Caravan Park MM2 Blanchetown Golf Course A2 Clayton R3 Bert Dix Park MM3 Swan Reach Ferry A3 Goolwa North R4 Settler’s Bend MM4 Mannum Caravan Park A4 Goolwa R5 Renmark Golf Course MM5 Port Mannum A5 Port Elliot R6 Ral-Ral Bridge

MURRAY BRIDGE BERRI BARMERA MB1 Mypolonga School B1 Monash Playground MB2 Sturt Reserve B2 Glossop MB3 Murray Bridge Golf Course B3 Martin’s Bend MB4 Jervois Bowling Club B4 Berri Caravan Park MB5 Wellington Caravan Park B5 Cobdogla

COORONG LOXTON WAIKERIE C1 Tailem Bend Golf Course L1 Loxton Golf Course C2 East Wellington L2 Loxton Caravan Park C3 Poltalloch Bluff L3 Moorook Park C4 Waltowa Swamp L4 Kingston on Murray C5 Meningie School L5 Waikerie

10 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 3. Methods. Larval site locations and monitoring procedures. Larval sites were added to the study as they were discovered, being allocated a code consisting firstly of the letters of the closest corresponding adult trap site, followed by an ‘L’ and a number. Each site was labelled consecutively in order of discovery. Records of larval sites were kept on subsequent trips and larvae dipped there. Sites identified during the previous season were retained and the practice continued. A complete list and description of all larvae sites for each local council are provided in is supplied in Appendices 9-15. Larval dipping involved repeated sampling with a white plastic ladle around the edge of the water body, particularly amongst emergent vegetation. Larvae were preserved in 75% ethanol for later identification in the laboratory using the keys in “Mosquitoes and Mosquito-borne Disease in South-eastern Australia” by Russell [3] and “The Mosquitoes of Victoria” by N. V. Dobrotworsky [4].

Weather Data. Weather data were obtained from the Bureau of Meteorology (BoM) from a number of weather stations located along the River (Table 3.1). Rainfall and temperature data were presented as monthly summaries and compared with the long-term district average.

Table 3.1, the location of Bureau of Meteorology Weather Stations used in this study. Station Number Station Name Latitude Longitude Height 24012 Overland Corner -34.1479 140.3256 59 24024 Loxton Research Centre -34.439 140.5978 30.1 24025 Berri -34.2717 140.5964 50 24038 Waikerie Council Works Depot -34.1897 140.0043 40 24048 Renmark Aero -34.1983 140.6766 31.5 24517 Mannum Council Depot -34.9145 139.301 40 24518 Meningie -35.6902 139.3375 3 24521 Murray Bridge Comparison -35.1234 139.2592 33 24535 Swan Reach -34.5681 139.5971 12 24536 Tailem Bend -35.2546 139.4542 21 24564 Blanchetown Lock 1 -34.3515 139.6153 11 24578 Morgan (Brenda Park Station) -34.0647 139.6605 42 23718 Goolwa Council Depot -35.50 138.76 5

11 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 3. Methods.

River Flow Data. The level of the River Murray was gathered by surface water monitoring stations (Figure 3.2) recording both upstream and downstream pool levels of each lock along the South Australian section of the River Murray (Table 3.2). This provided an overview of river flow within the state. This season three additional site representing the Chowilla Creek wetlands Milang Jetty (Lake Alexandrina) and Meningie Sailing Club (Lake Albert) were also included to represent localised inundation. The River Murray level data has been provided by the Department of Water, Land and Biodiversity Conservation, DWLBC (2017). Table 3.2. Location River Murray Locks and DWLBC site codes. DWLBC Site Code Site Name Latitude Longitude A4260510 Lock 6 Upstream (619.8 km) 33.59.48S 140.53.14E A4260511 Lock 6 Downstream (619.8 km) 33.59.45S 140.53.12E A4260576 Monoman Creek at Bridge upstream Chowilla Creek 33:57:45S 140:52:25E A4260512 Lock 5 Upstream (562.4 Km) 34:11:19S 140:45:59E A4260513 Lock 5 Downstream (562.4 Km) 34:11:20S 140:45:58E A4260514 Lock 4 Upstream (516.2 Km) 34:20:31S 140:34:37E A4260515 Lock 4 Downstream (516.2 Km) 34:20:35S 140:34:38E A4260516 Lock 3 Upstream (431.4 Km) 34:11:21S 140:21:28E A4260517 Lock 3 Downstream (431.4 km) 34:11:21S 140:21:28E A4260518 Lock 2 Upstream (362.1 Km) 34: 4:37S 139:55:54E A4260519 Lock 2 Downstream (362.1km) 34: 4:37S 139:55:54E A4260524 Milang 34.24.21S 138. 58 .38E A4260630 Lake Albert at Meningie Sailing Club Jetty 35: 40:52S 139: 20:25E A4260902 Lock 1 Upstream (274.3km) 34.21.03S 139.36.56E A4260903 Lock 1 Downstream (274.3km) 34.21.03S 139.36.56E

Figure 3.2. DWLBC Site A4260514, River Murray Lock 4 Upstream (516.2 Km) 11th Jan 2008.

12 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 3. Methods. Arbovirus infection notification data. De-identified Ross River virus (RRV) Murray and Barmah Forest virus (BFV) data were supplied by the Communicable Diseases Branch of the SA Department of Health. Data for May 2016 to April 2017 were examined in order to seek correlations with the mosquito numbers in each area at that time.

Arbovirus detection project-passive traps/FTA cards. Due to the success of the new virus detection technologies (FTA cards) trailed in 2013-14 it continued to be incorporated into the current season's regular adult sampling program. As part of our regular sampling program, we inserted honey baited “FTA Cards” into two of the five EVS traps set in each council. Trap site locations were chosen on the basis of the likelihood of high mosquito numbers and the mix of vectors commonly caught at trap sites. The mosquitoes were then held in constant temperature rooms for up to five days or until all mosquitoes had died. Mosquito samples were then identified using the keys in “Mosquitoes and Mosquito-borne Disease in South-eastern Australia” by Russell [3] and “The Mosquitoes of Victoria” by N. V. Dobrotworsky [4]. The 'virus detection' of all FTA cards was undertaken by the Arbovirus Reference Laboratory in NSW. Following positive screening for RRV and high mosquito numbers, the proportion of EVS traps with FTA cards was increased. During the 2016-17 season Healthy Environment, Healthy People Research Group continued to trail passive CO2 baited mosquito traps fitted with an “FTA card” baited with a sugar source, in this instance Manuka honey (Richie et. al,[5] see Figure 3.3). The trial was conducted to identify if this system could be a reliable, cost-effective alternative arboviral monitoring method too expensive programs such as Sentinel Chicken flocks, live capture, and screening of mosquitoes. In the Current season, the South Australian Department of Health engaged the University of South Australia to deploy passive traps adjacent sentinel chicken flocks located at Qualco, The Rural City of Murray Bridge and Meningie. Two additional passive traps where sites at Loxton and Renmark some distance from sentinel chicken flocks. honey baited FTA Cards were collected twice times over the season to coincide with the arboviral screening of the flocks but the SA Department of Health. This program was implemented in co-operation with colleague’s interstate were the system was also being trailed by Scott Ritchie amongst others and with technical assistance from Giles Cortis.

Figure 3.3. Passive CO2 baited mosquito trap.

13 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 3. Methods.

The Passive trap system is not used to determine adult mosquito relative abundance rather is designed to be placed in the field for longer periods of time allowing visitation by female mosquitoes over this extended period. Some trials have included an insecticide impregnated FTA card that kills the mosquitoes once they have fed on it. The FTA card technology is promising; the advantages of this type of trap over conventional arbovirus monitoring (e.g. Sentinel Chicken flocks, live capture of mosquitoes) are the reliability, ease of use and apparent sensitivity. While the downside is the inability to identify actual vector species (traps may contain multiple species).

14 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

4. GENERAL RESULTS AND INFORMATION FOR ALL COUNCILS.

Arbovirus infection data 2016-2017. A complete list of probable and confirmed RRV and BFV notifications from May of 2016 until the end of April 2017 is supplied in Appendix 1. There were 525 RRV (430 probable, 95 confirmed), and 3 BFV (2 probable, 1 confirmed) notifications from the beginning of May 2016 through to the end of April 2017 (Table 4.1) compared with 78 RRV and 3 BFV notifications in the previous year. This appeared to be an increase in the previous season, however, changes in the case definitions for these arboviruses makes comparisons difficult. Of the 525 RRV notifications, slightly less than half or 238 notifications were attributed to River Murray communities as a likely source of infection (Table 4.2). While only one of the three BFV notification were attributed to the River Murray communities as a likely source of infection. No notifications of Murray Valley Encephalitis were reported during this period. Interestingly there were also a number of imported cases of arboviral disease including; 89 Dengue Fever cases and eight cases of chikungunya virus and nine imported cases of Malaria. No imported cases of Japanese encephalitis were reported during the period. Whilst notified cases are always an underestimation of the actual number of cases in the community, changes in reporting of serology results are contributing to uncertainty regarding human case numbers. This has resulted in a decline in RRV and BFV notifications over recent years, further changes this year have coincided with an increase in the overall probable cases of RRV across the state. There was also an increase in the confirmed cases to 95 up from the 78 recorded in the previous season. The variation in these estimates may be attributable to changes in reporting of serology results. There have been only three BFV cases reported this season, a similar level to the previous season. The incidence of state-wide arboviral infections over the surveillance period is shown in the figure below (Chart 4.1). While RRV infections were reported throughout the year state-wide there was a seasonal increase commencing in November and extending into April 2017. This period of elevated reporting reached its zenith in January and February. The highest number of reported cases with estimated date of onset occurred in January 2017 with 29 confirmed and 119 probable cases of RRV. There was a similar number in the following month with 28 confirmed and 111 probable cases of RRV across the state. RRV cases reportedly from the Riverland communities generally had a similar distribution across the season with the highest number of cases reported in January 2017 closely followed by February and December 2016 (Chart 4.2). the number of notifications attributed to the River Murray communities then decreased. 15 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

RRforecaster has been run routinely since Sep 2009 with the whole of valley forecasts. In March 2010 expectations of changing weather conditions forecasts were switched to more refined regional forecasts. This was instituted in November 2010 with each region examined routinely from this time. Reports were distributed each month in the form of ‘Mosquito Intelligence Reports’ provided some indication of the level of arboviral risk to the community within South Australia.

16 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

Table 4.1. Summary of incidence of Arboviral infections over the 2016-2017- season (May 2016-April 2017) in South Australia. Arboviral infection Total number of reported cases State-wide

Ross River Virus Probable 430

Confirmed 95

Total 525

Barmah Forest Virus Probable 2

Confirmed 1

Total 3

Table 4.2. Summary of incidence of RRV infections over the 2016-2017- season (May 2016-April 2017) associated with River Murray communities.

Berri and Barmera Loxton Waikerie Renmark Paringa Riverlands’

Alexandrina (DC) (DC) Coorong (DC) (DC) Mid Murray (DC) Murray Bridge (DC) (Indeterminate)

Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable Confirmed Total Probable May 1 0 1 1 0 1 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 June 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Jul 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Aug 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Sep 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 1 0 1 1 0 1 0 0 0 Oct 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 1 0 1 1 0 1 0 0 0 Nov 2 0 2 1 0 1 0 2 2 2 0 2 2 0 2 0 0 0 0 0 0 0 0 0 Dec 3 0 3 7 2 9 11 2 13 15 1 16 3 1 4 1 1 2 5 2 7 2 1 3 Jan 4 0 4 6 1 7 7 0 7 13 2 15 4 5 9 7 0 7 10 0 10 8 4 12 Feb 7 1 8 6 1 7 3 0 3 8 2 10 8 4 12 4 0 4 6 1 7 6 1 7 Mar 2 0 2 4 1 5 0 0 0 1 0 1 7 1 8 1 0 1 3 1 4 2 0 2 Apr 2 0 2 1 0 1 0 0 0 2 1 3 1 0 1 0 0 0 3 0 3 0 0 0 Total 21 1 22 27 5 32 21 4 25 43 6 49 26 11 37 15 1 16 29 4 33 18 6 24

17 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

Chart 4.1. Monthly Reported Arboviral infections (by calculated date of onset) in South Australia May 2016 to April 2017.

18 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

Chart 4.2. Monthly Reported Arboviral infections (by calculated date of onset) in River Murray Councils May 2016 to April 2017.

19 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

Arbovirus detection project-passive traps/FTA cards. FTA cards from the trial passive traps deployed adjacent the sentinel chicken flocks this season did not indicate the presence of any arbovirus. Unfortunately, the position of the sentinel flocks is constrained by a number of factors, and the locations were not optimal for the passive trap system. The FTA cards fitted to the regular mosquito surveillance traps indicated the presence of RRV in December at the Wellington Caravan Park (MB1). As a result, the numbers of FTA cards set in EVS traps was increased in subsequent collections (Table 4.3). In the subsequent collections during February, three more detections of arboviruses were made in including Sindbis virus (SINV) from the EVS trap at Morgan (MM1), a detection of Kokobera Virus (KOKV) from the EVS trap at Mypolonga (MB1) and Barmah Forest virus (BFV) detected from the EVS trap at Wellington Caravan Park (MB5).

This season 192 FTA cards were set in EVS traps and Passive CO2 Baited Traps along the River Murray compared to 163 in the previous season.

Table 4.3. The number of FTA cards set within each council and arboviral detections.

Mid Murray

Alexandrina

RuralCity of

BerriBarmera

Murray Bridge

Loxton Loxton Waikerie

CoorongDistrict

Renmark Paringa

cards Virus cards Virus cards Virus cards Virus cards Virus cards Virus cards Virus August 2 2 2 2 2 2 2 September 2 2 2 2 2 2 2 October 2 1 3 2 2 2 2 November 2 2 2 2 2 2 2 December 4 4 4 4 4 RRV 4 4 January 5 5 5 5 5 5 5 BFV, SINV February 2 3 2 4 4 KOK 4 2 March 5 4 6 7 7 5 4 April 2 2 2 2 2 2 2

20 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

River Levels. The level of the River Murray measured downstream of each lock within South Australia over the twelve months to May 2017 was complex. The state received an unregulated flow event from the middle of the year through to the end of the year. Pool level initially increased rapidly, then from early September, the increase was more gradual until late December 2016 when there was a sharp decline in the river level. This sharp decline in river levels had the potential to facilitate the formation of small ponds and other potential mosquito larvae habitats (Chart 4.2). This period of increased pool level was mirrored in the downstream pool levels of the lock immediately upstream. The pool levels upstream tended to mirror the downstream pool level of the subsequent lock only around the periods of peak flow. Otherwise, upstream pool levels were relatively flat with little variation. This pattern broke down in the lower locks Lock 1 and 2 where the pool level more closely matched the fluctuations in the downstream pool levels. During May and into October 2016, there was an increase in the level of Lake Albert measured at Meningie from 0.6 m to 1 m, and Lake Alexandrina measured at Milang from 0.5 m to 0.94 m. This was followed by a decline in the level of the lower lakes through November 2016, and a brief increase in December 2016 and a final decline into the new year (Chart 4.3). As with the previous season, localised inundation at Chowilla Creek A4260576 was higher over a longer period than the adjacent lock 6.

21 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

Chart 4.2. River levels Upstream and Downstream of Locks during the 2016-2017 season.

A4260576 14 A4260510

12 A4260511 A4260512

10 A4260513 A4260514

River Height AHD (m) 8 A4260515 A4260516 6 A4260517 A4260518 4 A4260519

Date

DWLBC (2017). Unpublished Data. Department of Water, Land and Biodiversity Conservation. 22 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 4. General results and information for all councils.

Chart 4.3. Lake Albert (Meningie) and Lake Alexandrina (Malang) levels at and during the 2016-2017 season.

1.3

1.2

1.1

0.9

0.8

0.7 River River Height AHD (m)

0.6

0.5

0.4

0.3

Date A4260630 A4260524 14 per. Mov. Avg. (A4260630) 14 per. Mov. Avg. (A4260524)

23 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

5. RESULTS FOR THE RENMARK PARINGA COUNCIL. Adult trap site descriptions.

R1 Chaffey Irrigation Area (site used up to 30/9/05, replaced by R6 during 05-06 season)

Directions: Travel along Ral-Ral road from Renmark; turn right at Ibis, turn right into Teal St. Longitude : E140 43.063 Latitude : S34 06.250

R2 Riverfront Caravan Park - Renmark Longitude: E140 45.772 Latitude: S34 10.732 Riverfront Caravan

Murray Sample River BBQ site

Sturt Backwater Highway From

Renmark

24 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

R3 Bert Dix Memorial Park, Paringa

Directions: First right off Sturt after crossing the bridge from Renmark Longitude: E140 46.627 Latitude: S34 10.991

Sturt Highway RENMARK

PARINGA River

Murra

Bert Dix Memori

Apex Sample site

playground R4 Settlers Bend

Directions: Travel towards Berri turn down toward Murray River on 27th Street. Continue until NO THROUGH ROAD SIGN, turn left and drive past green weatherboard house. Longitude: E140 44.119 Latitude: S34 13.247

25 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

R5 Renmark Golf Club

Longitude: E140 41.629 Latitude: S34 12.928

26 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

Weather Data: Renmark Paringa Council.

Weather data were supplied from Renmark Aerodrome Weather Station (station 24048) of the Bureau of Meteorology. Seasonally, Renmark had a cooler spring, with both days and nights cooler than the mean daily maximum and minimum temperatures the long-term trends for this period (Chart 5.2). The lower than long-term trends were more pronounced in September 2016 with the daily mean temperature only reaching 19.3 °C well below the long-term trend of 22.2°C. These conditions continued in October and through to November as the deviation from the long-term means daily Maximum temperature gradually narrowed. Conditions then continued to trend more towards long-term trend over summer with some variation around historic temperatures. The month of March was an exception with daytime temperatures 2.7 °C higher than the long-term mean over the month. Over spring the Minimum daily temperatures showed the opposite pattern, approximating the long-term trends in September then over October and November 2016 nights become increasingly cooler compared to long-term trends. This changed abruptly in December 2016 where nights became on average slightly warmer than long- term conditions (Chart 5.2). Into the new year, nights were mostly warmer than long- term trends with the exception of February which was 0.8 °C cooler than long term trends. The remainder of the of the season was 1.8 °C warmer than long-term trends for both March and April, 2017. The 14-day moving average for the minimum temperatures (14DMADMin) first exceeded 15 ºC in late December 2016 (Chart 5.1) this was slightly later than the previous year. Once exceeding 15 ºC the 14DMADMin rapidly rising to 19 ºC by New Year’s Day before falling back again but remained above 15 ºC until mid-March 2017. Following this, the 14DMADMin only dropped below 15 ºC for just under two weeks until the end of the month, then exceeded this level for a most of the remainder of the month. There was a cool period in the middle of the month where the 14DMADMin dropped below 15 ºC for around three days. The 14-day moving average maximum daily temperature (14DMADMax) first exceeded 25 ºC in the last few days of October 2016, this was around a month later than the previous season. With the exception of the 4-5th of April, the 14DMADMax remained above 25 ºC until the middle of April 2017. During this period, the 14DMADMax exceeded 30 ºC on three occasions ranging from a day to around nine weeks. The longest

27 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Weather Data warm period extended from mid-December 2016 into the mid-March 2017 within this period there was only 3 consecutive days in January with the 14DMADMax remained above 35 ºC. Total annual precipitation to May 2017 at Renmark Weather Station 357.4 mm was over twice the amount recorded over the previous season (144.6 mm), and exceeded the Historic Mean (245.1 mm) by 112.1 mm. Total precipitation over the three winter months approximated the long term mean 20.6 mm. This was largely due to a very wet September with 102 mm recorded in the month, this was followed by two months of average precipitation. This resulted in a relatively wet spring with the cumulative total spring exceeding the long-term average by 80.9 mm at the Renmark Weather station. Apart from a dry February and March 2017, the remainder of the season was slightly above the long- term trends.

28 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Weather Data

Chart 5.1. Renmark Aerodrome Weather Station (24048) Maximum and Minimum Temperature with 14-day Moving Average from May 2016 to April 2017.

30 C

° 25

15 Temperature Temperature

Date Chart 5.2. Renmark Aerodrome Weather Station (24048) Monthly Mean Maximum and Minimum Temperature May 2016 to April 2017 compared to historic means (solid line). 40 Mean max temp 2016-17 Historic mean Mean min temp 2016-17 Historic min

25 C

20°

10 Temperature

0 May June July August September October November December January February March April Month

29 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Weather Data

Chart 5.3. Total Monthly Precipitation (mm) at Renmark Aerodrome Weather Station (24048) during the 2016-17 Trapping Period Compared with the Historic Mean.

120 Total precipitation Historic Mean

100

Precipitation(mm) 40

0 May June July August September October November December January February March April Month

NOTE: Figures above run from May 2016, four months before the start of this sampling season.

30 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

Adult mosquito trapping results: Renmark Paringa Council. Chart 5.4. Renmark Paringa Council Area, total adult Cx. australicus and An. annulipes adult female mosquitoes caught in the 2016-17 season.

Chart 5.5. Renmark Paringa Council Area, total and secondary species of adult mosquitoes caught in the 2016-17 season.

31 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Weather Data

Chart 5.6. Renmark Paringa Council Area, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

32 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. – Adult Data Table 5.1. Totals for the five traps in Renmark Paringa Council Area.

27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 17/12/16 12/01/17 7/02/17 2/03/17 27/03/17 25/04/17 Season Total Species Ae. alboannulatus 0 0 0 1 0 0 0 0 0 0 0 1 Ae. camptorhynchus 35 169 404 578 97 27 129 129 415 4 20 2007 Ae. notoscriptus 1 0 0 5 1 1 0 0 0 10 4 22 An. annulipes 0 0 4 2 0 10 0 0 1 0 1 18 Cq. linealis 0 0 0 1 1 0 10 10 85 5 0 112 Cx. annulirostris 0 0 0 0 0 1 1 1 10 0 0 13 Cx. australicus 0 0 1 5 2 1 0 0 0 0 3 12 Cx. globocoxitus 0 3 5 13 6 7 9 9 9 1 0 62 Cx. molestus 5 0 3 6 15 12 3 3 31 21 21 120 Cx. quinquefasciatus 0 0 4 0 1 7 28 28 6 3 0 77 Unidentifiable 0 0 0 0 0 0 0 0 2 0 0 2 Male 0 0 1 0 1 0 0 0 3 0 0 5

no captures 0 1 0 0 0 0 0 0 3 3 0

Trap failure 0 1 0 0 0 2 0 0 0 0 1 Total Adults 41 172 421 611 123 66 180 180 559 44 49 2446

n=5 n=4 n=5 n=5 n=5 n=3 n=5 n=5 n=5 n=5 n=4 Total (n=51)

33 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Weather Data Table 5.2. Average Catch for the five traps in Renmark Paringa Council Area.

Species 29/8/16 22/9/16 17/10/16 9/11/16 3/12/16 21/12/16 14/1/17 10/2/17 5/3/17 29/3/17 25/4/17 Ae. alboannulatus 0 0 0 0 0 0.33 0 0 0 0 0 SE 0 0 0 0 0 0.258 0 0 0 0 0 Ae. camptorhynchus 3 8 25.6 15 12.2 8 3.2 0 0 0 0 SE 2.28 5.279 15.089 6.072 7.088 4.733 2.478 0 0 0 0 Ae. clelandi 0 0 0 0.2 0 0 0 0 0 0 0 SE 0 0 0 0.224 0 0 0 0 0 0 0 Ae. notoscriptus 0.2 0 0 0 0.2 0.33 0 0.2 0 0 1.75 SE 0.2 0 0 0 0.2 0.258 0 0.2 0 0 1.75 Ae. sagax 0.2 7.75 0 4.6 8.6 0.67 0 0 0 0 1.25 SE 0.2 5.801 0 1.673 4.729 0.258 0 0 0 0 0.479 An. annulipes 2 2.25 18 464.6 198.4 60.33 1.2 1.6 0.2 0.2 0.5 SE 1.265 0.764 5.03 207.667 149.016 16.152 0.49 0.748 0.2 0.2 0.5 Cq. linealis 0 0 0.2 11.6 2.6 0.33 1 0.6 0.4 0.4 0.25 SE 0 0 0.2 8.497 2.112 0.258 0.548 0.4 0.4 0.4 0.25 Cx. annulirostris 0.6 0 0.2 13 23.4 87 15 4.8 0.4 0.4 0.25 SE 0.4 0 0.2 8.996 12.34 41.289 6.626 2.923 0.4 0.4 0.25 Cx. australicus 3.8 34 408.8 82.6 42.4 26 1.2 0 0 0 0.25 SE 2.083 21.348 161.439 20.534 10.191 6.261 0.583 0 0 0 0.25 Cx. globocoxitus 1 0.25 3.6 6.4 0 0 0 0 0 0 0.5 SE 0.447 0.224 2.135 4.463 0 0 0 0 0 0 0.5 Cx. molestus 1.2 0 0 2.6 1 0 0.2 0.2 0 0 2 SE 0.735 0 0 2.907 0.632 0 0.2 0.2 0 0 2 Cx. quinquefasciatus 1.6 0 3 2.8 1.6 0 0.4 0.4 0 0 1 SE 0.928 0 1.643 2.045 1.6 0 0.4 0.245 0 0 0.578 Ma. uniformis 0 0 0 0 0 0 0.4 0.4 0.4 0.4 0.25 SE 0 0 0 0 0 0 0.4 0.4 0.245 0.245 0.25 Unidentifiable 0 0 0 0.4 0.6 0.33 0 0.4 0 0 0 SE 0 0 0 0.447 0.6 0.258 0 0.245 0 0 0 Male 0 0 0 0.2 0.2 0 0 0 0 0 0 SE 0 0 0 0.224 0.2 0 0 0 0 0 0 no captures 0 1 0 0 0 0 0 0 3 3 0 Trap failures 0 1 0 0 0 2 0 0 0 0 1 Total Adults 13.6 52.25 459.4 603.8 291 183.33 22.6 8.6 1.4 1.4 8 SE 4.434 32.09 165.736 206.999 167.721 60.456 10.366 3.429 0.872 0.872 3 n=5 n=4 n=5 n=5 n=5 n=3 n=5 n=5 n=5 n=5 n=4

34 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. – Adult Data

Mosquito Larval Dipping and Treatment: Renmark Paringa Council.

Table 5.3. Results of Larval Dipping within Renmark Paringa Council.

An. annulipes An.

Larvae present

Cx. Cx. australicus

Cx. Cx. globocoxitus

Site Condition Site Ae. camptorhynchus Ae. Site Trip Date Density R3L11 1 27/8/2016 Receding Yes * High R1L9 1 27/8/2016 Full Yes * Low R1L2 2 22/9/2016 Full Yes * Low R1L8 2 22/9/2016 Full Yes * High R1L9 2 22/9/2016 Full Yes * High R1L28 2 22/9/2016 Full No R1L29 2 22/9/2016 Full No R1L30 2 22/9/2016 Full Yes * High R1L41 2 22/9/2016 Full No R1L27 2 22/9/2016 Full No R1L37 2 22/9/2016 Full Yes * Medium R1L39 2 22/9/2016 Full No R1L53 2 22/9/2016 Full No R1L54 2 22/9/2016 Full No R1L55 2 22/9/2016 Full Yes * Medium R1L56 2 22/9/2016 Full Yes * Low R1L57 2 22/9/2016 Full Yes * High R2L5 2 22/9/2016 Full Yes * High R2L8 2 22/9/2016 Full Yes * High R2L12 2 22/9/2016 Full Yes * Medium R2L16 2 22/9/2016 Full No R2L23 2 22/9/2016 Full Yes * Medium R2L27 2 22/9/2016 Full Yes * Medium R2L28 2 22/9/2016 Full Yes * High R4L4 2 22/9/2016 Full Yes * * Low R4L16 2 22/9/2016 Full Yes * Low R1L31 3 17/10/2016 Full Yes * Low R1L32 3 17/10/2016 Full Yes * Low R2L3 3 17/10/2016 Full No R2L19 3 17/10/2016 Filling No R3L9 3 16/10/2016 Full No R5L2 3 17/10/2016 Full Yes * High R5L3 3 17/10/2016 Full Yes * High R1L17 Other 23/10/2016 Full Yes * Medium R1L31 Other 23/10/2016 Full * R1L32 Other 23/10/2016 Full Yes * R1L48 Other 23/10/2016 Full Yes * High R1L58 Other 23/10/2016 Full Yes * Medium R1L59 Other 23/10/2016 Full Yes * Medium R1L60 Other 23/10/2016 Full Yes * Low R1L61 Other 23/10/2016 Full Yes * Medium R1L62 Other 23/10/2016 Full Yes * Medium R1L9 Other 23/10/2016 Receding Yes * Medium R2L16 Other 23/10/2016 Receding Yes * High R4L7 Other 23/10/2016 Full Yes * Medium R2L1 4 10/11/2016 Full Yes * High R2L9 4 10/11/2016 Full Yes * High R2L12 4 10/11/2016 Full Yes * High R2L28 4 10/11/2016 Full Yes * Medium R2L32 4 10/11/2016 Full Yes * * Medium R2L35 4 10/11/2016 Full Yes * Medium

35 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

5. Results Renmark Paringa Council.

An. annulipes An.

Larvae present

Cx. Cx. australicus

Cx. Cx. globocoxitus

Site Condition Site Ae. camptorhynchus Ae. Site Trip Date Density R2L38 4 10/11/2016 Full Yes * High R2L39 4 10/11/2016 Full Yes * High R1L2 5 3/12/2016 Full Yes * Medium R1L6 5 3/12/2016 Full Yes * Medium R1L7 5 3/12/2016 Full Yes * Medium R1L8 5 3/12/2016 Full No R1L9 5 3/12/2016 Full No R1L10 5 3/12/2016 Full No R1L11 5 3/12/2016 Full No R1L13 5 3/12/2016 Full No R1L14 5 3/12/2016 Full No R1L15 5 3/12/2016 Full No R1L37 5 3/12/2016 Full No R1L62 5 3/12/2016 Full No R2L4 5 3/12/2016 Full No R2L7 5 3/12/2016 Full No R2L8 5 3/12/2016 Full Yes * High R2L9 5 3/12/2016 Full No R2L12 5 3/12/2016 Full Yes * Medium R2L13 5 3/12/2016 Full No R2L19 5 3/12/2016 Full No R2L22 5 3/12/2016 Full No R2L25 5 3/12/2016 Full Yes * Low R2L28 5 3/12/2016 Full No R2L30 5 3/12/2016 Full Yes R2L31 5 3/12/2016 Full Yes * Medium R2L32 5 3/12/2016 Full No R2L33 5 3/12/2016 Full No R2L34 5 3/12/2016 Full No R2L36 5 3/12/2016 Full Yes * Low R2L37 5 3/12/2016 Full Yes * Low R4L15 5 3/12/2016 Full No R2L3 6 21/12/2016 Full Yes * Low R1L9 7 14/1/2017 Receding No R2L3 7 14/1/2017 Full Yes R2L6 7 14/1/2017 Full No R2L12 7 14/1/2017 Full No R2L25 7 14/1/2017 Full No R2L36 7 14/1/2017 Full No R2L37 7 14/1/2017 Full No R3L6 7 14/1/2017 Full No R3L12 7 14/1/2017 Full No R2L5 8 10/02/2017 Full No R2L7 8 10/02/2017 Full No R2L12 11 25/4/2017 Receding No

36 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. – Larvae Data

Renmark Paringa Larvicide Applications. The dramatic change in conditions experienced several years ago continue to influence the mosquito community in the upper River Murray. During September 2016 rain and a higher river combined to activate several larvae sites of the cool weather species Ae. camptorhynchus particularly around Goat Island (Paringa Paddock). These sites were monitored throughout the season and treated with S-Methoprene briquettes and BtI where required. The majority of these sites were treated with briquettes providing long term treatment of these sites. Fortunately, the large rain event in September coincided with the seasonally cooler weather this resulted in conditions that were not suitable for the recruitment of the major arboviral vector Cx. annulirostris but favoured the less problematic species Cx. australicus. Larvae control and monitoring were increased in spring due mainly to public perception and the concern around mosquito numbers. Sites that could harbour more problematic species when the weather warmed such as Cx. annulirostris were prioritised Monitoring of known larval sites continued over the season with particular attention to known problem sites and additional pre-emptive treatment of a number of sites with S-Methoprene briquette was conducted in April 2017 to reduce over winter larvae activity.

37 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. – Larvae Data

Table 5.4. Larvicide application in Renmark Paringa Council during the 2016-17 season.

Site Date Product Quantity Site Date Product Quantity R3L11 27/8/2016 Briquettes 6 R2L2 10/11/16 Briquettes 3 R1L9 27/8/2016 Pellets 100 gm R2L1 10/11/16 Briquettes 3 R1L2 22/9/2016 Briquettes 1 R2L9 10/11/16 Briquettes 32 R1L8 22/9/2016 Briquettes 2 R2L12 10/11/16 Briquettes 2 R1L9 22/9/2016 Pellets 100 gm R2L32 10/11/16 Briquettes 2 R1L28 22/9/2016 Briquettes 4 R2L35 10/11/16 Briquettes 3 R1L29 22/9/2016 Briquettes 1 R2L38 10/11/16 Briquettes 6 R1L30 22/9/2016 Pellets 100 gm R2L39 10/11/16 Briquettes 4 R1L41 22/9/2016 Briquettes 4 R1L2 3/12/16 Briquettes 10 Pellets 300 gm R1L6 3/12/16 Briquettes 10 R1L37 22/9/2016 Pellets 100 gm R1L7 3/12/16 Briquettes 10 R1L39 22/9/2016 Pellets 200 gm R2L8 3/12/16 Briquettes 8 R1L53 22/9/2016 Briquettes 2 R2L12 3/12/16 Briquettes 12 R1L54 22/9/2016 Briquettes 2 R2L25 3/12/16 Briquettes 1 R1L55 22/9/2016 Pellets 100 gm R2L31 3/12/16 Briquettes 2 R1L56 22/9/2016 Pellets 100 gm R1L57 22/9/2016 Pellets 100 gm R2L36 3/12/16 Briquettes 5 R2L37 3/12/16 Briquettes 2 Briquettes 4 R2L5 22/9/2016 Briquettes 7 R2L3 21/12/2016 Briquettes 15 R2L8 22/9/2016 Pellets 100 gm R2L1 14/1/2017 Briquettes 2 R2L12 22/9/2016 Briquettes 6 R2L6 25/4/2017 Briquettes 8 R2L23 22/9/2016 Briquettes 8 R2L8 25/4/2017 Briquettes 4 R2L27 22/9/2016 Briquettes 4 R1L9 25/4/2017 Briquettes 20 R2L28 22/9/2016 Pellets 200 gm R2L12 25/4/2017 Briquettes 6 R4L4 22/9/2016 Pellets 100 gm R2L25 25/4/2017 Briquettes 1 R4L16 22/9/2016 Briquettes 5 R2L36 25/4/2017 Briquettes 2 R2L3 17/10/2016 Pellets 100 gm R2L38 25/4/2017 Briquettes 2 R2L19 17/10/2016 Pellets 100 gm R2L22 17/10/2016 Pellets 400 gm R2L39 25/4/2017 Briquettes 7 R2L34 17/10/2016 Pellets 100 gm R2L35 17/10/2016 Pellets 100 gm R3L9 16/10/2016 Pellets 100 gm R5L2 17/10/2016 Pellets 1000 gm R5L3 17/10/2016 Pellets 1000 gm R1L16 23/10/2016 Briquettes 3 R1L17 23/10/2016 Briquettes 1 R1L31 23/10/2016 Briquettes 8 R1L32 23/10/2016 Briquettes 10 R1L42 23/10/2016 Briquettes 2 R1L48 23/10/2016 Pellets 100 gm Briquettes 5 R1L58 23/10/2016 Briquettes 23 R1L59 23/10/2016 Briquettes 3 R1L60 23/10/2016 Briquettes 4 R1L61 23/10/2016 Briquettes 2 R1L62 23/10/2016 Briquettes 2 R1L9 23/10/2016 Briquettes 10 R2L16 23/10/2016 Briquettes 14 R4L7 23/10/16 Briquettes 16

38 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

Discussion of Renmark Paringa results.

Adult Mosquitoes. A total of 7, 800 (n=51) adult female mosquitoes were trapped within the Renmark Paringa Council area during the 2016-17 season (summarised in Table 5.1), this was nearly eight times (7.75) of the previous seasons catch (adjusted for n=55), and the third highest adult mosquito catch in the eighteen years of this program (Table 5.5). The largest numbers of adult female mosquitoes were caught in the early part of the season, during October and into November 2016 (Chart 5.6). Like the previous year, this pattern is similar to the historic observations that were disrupted as a result of the floods and a high river of 2010-11. However, this is misleading as the dominate early season species were not the cool weather Aedes species Ae. camptorhynchus, but rather a combination of Cx. australicus and An. annulipes. The distribution of Adult female mosquitoes differed from the long-term trends in that the initial increase in mosquito numbers occurred a month later in November rather than in October. It is curious that the higher than average rain recorded in December and January which coincided with the drop in the high river did not result in increased numbers of mosquitoes. In particular An. annulipes which were recorded in large numbers a month earlier. The most abundant species caught in the council was An. annulipes comprising 46.5 % of all adult female mosquitoes caught in the council during the 2016-17 season. An. annulipes was also the most abundant species in the 2015-16 season although this was an increase in both the overall numbers and percentage of the total number of mosquitos caught. The next most abundant mosquito recorded in adult traps was Cx. australicus, which comprised of the majority of remaining mosquitoes at around 37.3% of the total catch. The important vector species Cx. annulirostris was also well represented in the mosquito community being the fifth most abundant mosquito species and comprising around 7 % of the total adult mosquito catch in the council. While Ae. camptorhynchus made up half of the remaining roughly 9 % of mosquitoes the other 4.5 % was quite diverse. was very diverse composed in order of decreasing abundance; Ae. sagax, Cq. linealis, Cx. australicus, various Culex species and Ae. notoscriptus. The single major spike in mosquito numbers during the early part of the 2016-17 season was predominantly made up of An. annulipes and the cool weather mosquito Cx. australicus. The high numbers of An. annulipes pushed the peak in mosquito numbers into the warmer months and was probably due to the high river resulting from the unregulated flow experienced this season. The cool weather Culex species Cx. australicus caused much concern due to the sheer numbers early on in the season and its similarity to the major arboviral vector Cx. annulirostris.

39 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Discussion.

The cool weather species is species Ae. camptorhynchus had all but disappeared from the upper river following the high river of 2010-11, but has re-established and has featured as a common mosquito over recent seasons, targeted control efforts are probably responsible for the relatively low numbers observed this season.

Species worthy of consideration include:

An. annulipes (3, 623 or 46.5 % of total catch) was the most abundant species captured within the Renmark Paringa Council area, this species was the most abundant species in the previous season (294, or 29.2% of total catch). However, this was still an increase from the previous year both in terms of overall numbers and relative abundance. An. annulipes was strongly represented in the late spring and persisting through summer adult mosquito catches. The numbers of this species rapidly increased early in the season and peaking during November to a maximum of 2, 323 individuals (77 % of Novembers catch in, Chart 5.4). The numbers then declined precipitously and remained at low for the remainder of the season. As with previous seasons An. annulipes was found to be relatively common at two of the five adult trap sites within the council, R1 (Chaffey Irrigation Area), R2 (Renmark Caravan Park) where 177 and 1, 160 individuals were trapped (19.9 % and 65.5% of the total catch at that site). Unlike the previous season where only a few individuals were caught, An. annulipes comprised over half (52.4 %) of the individuals caught at Bert Dix Memorial Park (R3) or 1, 863 individuals. There was also a dramatic increase on the 26 individuals caught at Settlers Bend (R4) in the previous season with 325 individuals caught this season over ten times that number. Few individuals (5) were captured at the Renmark Golf course (R5). Cx. australicus (2, 909, or 37.3% of total catch) was the second most abundant species in the 2016-17 season and the most widespread mosquito species. This Culex species tends to be trapped in cooler weather, often in spring and autumn, this was consistent with this season with the peak in numbers occurring in late October (2, 044, n=5) prior to the peak in An. annulipes numbers. Most Cx. australicus individuals (1, 127) were caught Bert Dix Memorial Park (R3), where it also made up 31.2 % of all individuals at this site. However, this species was caught in large numbers at Chaffey Irrigation Area (R1) and Settlers Bend (R4) and the Renmark Caravan Park (R2) (629, 587 and 246 individuals and comprising 71 %, 53.2 % and 14 % of the catch at each site respectively). Cx. australicus was also the most abundant at Renmark Golf course (R5) where 197 individuals were trapped comprising 86 % of all mosquitoes caught at this location.

40 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Discussion.

Cx. annulirostris (551, or 7% of total catch) was the third most abundant species identified within the 2016-17 season this species is considered to be a major vector of arbovirus in inland Australia during the warm months. This is below the long-term trends in relative abundance of this species which comprises around 27% of all the historic mosquito data from this council. Variation is not surprising as this is a species which quickly responds to conditions. This species was present in at least low numbers from October 2016, with the highest numbers recorded in January (28, n=4) (Chart 5.6). Cx. annulirostris was found to be common at only three sites within the council R1, R2, R3 and R4 (42, 7.7%, 3, 138, 7.8 %, 304, 8.5% and 61, 5.5 % total numbers and percentage of catch for each site respectively). Ae. camptorhynchus (351, or 4.5 % of total catch) is often one of the most abundant mosquito species along the river, having contributed 56 % of the total catch across all previous years (Table 12.2). This season this species was the fourth most abundant species within the Renmark council this season. In the years following the large flood event of 2010-11, this species has hardly recorded in the upper river. The sharp decline in the total population of Ae. camptorhynchus along with its dominance of the spring catch was believed to be due to the removal of the egg bank from floodplain sites within the council. Following a number of seasons of very low numbers, this species became the most abundant species 2014[6], and the second most abundant in 2015 [7]. Rainfall over winter approximated long term means with above average rainfall in August and September precipitation five times long term would seem like ideal conditions for recruitment of Ae. camptorhynchus (Chart 5.4). This, however, coincided with an unregulated flow event that may have compromised many larvae sites, in addition, many of the known larvae sites where treated which seems to have been effective. The distribution of Ae. camptorhynchus over the season matched closely with that of Cx. australicus, with a peak in abundance occurring in October 2016 (128, n=5) then numbers of this species then declined somewhat through to December 2016 then rapidly disappeared with only 16 individuals caught in January then no other individuals were caught for the remainder of the season. This species was present in all the trap sites within this council, however, as with the previous season it was most abundant at The Renmark Caravan Park 167 adult females were caught representing 48 % all individuals of this species caught within the council during 2016-17. It was also the third most abundant species at this site representing 9.4 % of the mosquitoes at this site. This was followed by followed by Bert Dix Memorial Park (114 individuals) and Settlers Bend (62 individuals) representing 33% and 18% of all individuals caught within the council this season. Cq. linealis (86, or 1.1% of total catch) was the fifth most abundant component of the mosquito fauna within the Renmark Paringa Council area through the 2016-17 season (Chart 5.4).

41 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. - Discussion.

This is a decline in the total catch over previous seasons and a fraction of the historic catch of around 10% of the total catch within this council. As with the previous seasons, this species was represented in the catch from R2 (Renmark Caravan Park) making up 1.5 % of all species from this location. This species was also well represented at Bert Dix Memorial Park (R3) with 55 individuals caught at this location. As the emergent vegetation has re-established following the floods of 2010/11 plant breathing mosquito species like Cq. linealis and Ma. uniformis have returned and are established. These species generally utilise specific habitats and are often caught at the same locations over subsequent years.

42 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. Table 5.5. Summary of all monitoring seasons Renmark Paringa Council. FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/2003 2003/2004

Rainfall Heavy, Late Light, Sept, Jan. Low, one fall in Oct. Early light falls (Sept.) & then dry Peak in Aug River Levels No data Peaks, Oct and Dec. The small peak in Nov. No extraordinary peaks Elevated between Aug and Oct. Total female Mosquitoes 3, 997 (n=44) 6, 969(n=54) 1, 344 (n=55) 1, 228 (n=54) 1, 626 (n=54) Mosquito Peak March December February January November /December Dominant Species Cx. annulirostris Ae. camptorhynchus Cq. linealis Cq. linealis Cq. linealis Reported arbovirus infections ~35 (RRV) ~2 (RRV) ~2 (RRV) ~2 (RRV) ~3 (RRV)

FEATURE 2004/2005 2005-2006 2006-2007 2007-2008 2008-2009

Average winter, Peak in Aug, Rainfall Peak in Dec/Jan Generally High, Peak in Oct Low, Jan, March-April peaks Low in Spring high in Summer Nov/Dec River Levels No extraordinary peaks Lock raised in Spring. No extraordinary peaks No extraordinary peaks No extraordinary peaks Total female Mosquitoes 2, 668 (n=54) 13, 060 (n=52) 862 (n=52) 782 (n=53) 2, 125 (n=53) Mosquito Peak October / December October/ February November/ February November/ March September/October/January/April Dominant Species Ae. camptorhynchus/ Cq linealis Ae. camptorhynchus / Cq. linealis Cq. linealis Cq. linealis Ae. camptorhynchus Reported arbovirus infections ~4 (RRV), ~3(BFV) ~21 (RRV) 2 (RRV) 4(RRV), 1 (BFV) 11(RRV), 1 (BFV)

FEATURE 2009/2010 2010/2011 2011/2012 2012/2013 2013/14

Rainfall Average, peaks in Sept/ Nov/March Average, wetter November/ March Above average Oct-Jan, & March Higher than Average July Feb rain event Raised downstream pool levels in Below Lock 5 increasing Aug to Feb, Variable, High until Oct., Jan. Variable levels downstream of Water level raised downstream River Levels Summer Feb & March above lock high in mid-Jan pulse, flood in April. locks first half of season of Lock Total female Mosquitoes 914 (n=51) 16, 254 (n=54) 1, 599 (n=51) 1, 445 (n=52) 899 (n=53) Mosquito Peak October/ March January April September / February/ March October/ March Ae. camptorhynchus/ Cq. linealis / Cx. Dominant Species Cx. annulirostris Cx. annulirostris Cx. annulirostris/ An. annulipes Cq. linealis/ An. annulipes quinquefasciatus Reported arbovirus infections 21 (RRV), 3 (BFV) 51 (RRV), 15 (BFV) 8 (RRV), 3 (BFV) 9 (RRV), 3 (BFV) 2 (RRV)

43 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. Summary of all monitoring seasons Renmark Paringa Council (cont.). FEATURE 2014/15 2015/16 2016/17

Rainfall Early January rain event January rain event September and January rain event Raised around lock 6 and Chowilla Creek River Levels Raised downstream of locks in spring Unregulated flow, last half of 2016 in spring Total female Mosquitoes 1, 323 (n=53) 1, 006 (n=51) 7, 800 (n=51) Mosquito Peak August/ September August/ September November Dominant Species Ae. camptorhynchus/ Cq. linealis An. annulipes/ Ae. camptorhynchus An. annulipes/ Cx. australicus Reported arbovirus infections 6 (RRV) 2 (RRV) 33 (RRV, 29 probables, 4 confirmed)

44 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

COMMENTS.

During the 2016-17 season a total of 7, 800 (n=51) adult female mosquitoes were trapped within the Renmark Paringa Council area (summarised in Table 5.1), this was nearly eight times (7.75) of the previous seasons catch[7] (adjusted for n=55), and the third highest adult mosquito catch in the eighteen years of this program (Table 5.5). The largest numbers of adult female mosquitoes were caught in the early part of the season, during October and into November 2016 (Chart 5.6) with the largest collections obtained at Bert Dix Memorial Park (R3) where 47 % of the total council collections were made. The smallest collections made at the Renmark Golf Club (R5) which produced only 3% of the total catch within the council. During early-season, conditions were favourable for Cx. australicus particularly with the high precipitation recorded in September 2016. Population increased reaching a peak in October with 2, 323 individuals collected across the five trap sites. The cooler than average daytime temperatures were fortuitous as it created conditions more suited to this species rather than the more problematic vector species Cx. annulirostris. Cx. annulirostris requires pool temperatures greater than occurred over this period before populations increase [8] Cx. australicus is not a species of concern with regard to human health [3], however, the sheer numbers of this species following several years of low mosquito populations caused some concern in the community. In response to these concerns, Stephen Fricker was asked to undertake radio interviews. In addition, this species has the potential to act as a proxy in a similar manner to Cx. globocoxitus[2], providing an indication of available suitable habitat for the vector species Cx. annulirostris once conditions warm sufficiently. With this in mind and in response to community concern increased treatment of larvae sites of concern, that is suitable for the vector species Cx. annulirostris was undertaken over spring 2016. Following the peak in abundance in November 2016 Cx. australicus declined in abundance and was not practically absent from collections in the new year. The mosquito community then changed in November with An. annulipes increasing in numbers to become the most numerous species in collections through to late December (Chart 5.4). This is to be expected as this increase in collections coincided with suitable conditions for this species with the unregulated flow event reaching a zenith in mid-December (Chart 4.2). The distribution of An. annulipes across the council reflected these conditions with this species having higher abundance in collections closer to the River (R2 & R3) in November and December 2016. Collections of An. annulipes then declined in the new year although the species persisted throughout the season with a few individuals recorded each month.

45 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council. – Comments.

Following the persistent high river of 2010-11 the cool weather mosquito Ae. camptorhynchus was been practically absent from the mosquito fauna from 2011 until 2014. The reason for this is thought to have been the removed a large proportion of the egg bank of this species from the council area. The low numbers of Ae. camptorhynchus changed in the 2014-15 season with this species composing over half (51%) the mosquitoes in collections. It is important to note that an active larvae site was identified during the 2013-14 season and repeatedly treated throughout that and subsequent seasons. This was an indication that Ae. camptorhynchus was re-establishing in the upper river. This season the average rain over winter and higher than average September precipitation was a concern with regard to recruitment of Ae. camptorhynchus. However, only small numbers of adults were recorded in collections from the Renmark Paringa Council (Table 5.1), with many more individuals caught in the adjacent councils (Table 6.1, Table 7.1). The low numbers can be explained by the River Murray experiencing an unregulated flow event from late winter 2016 (Chart 4.2) rendering several known and presumably a number of unknown larvae sites inactive, and a comprehensive control effort of known active larvae sites (Table 5.3). Like the previous season Cq. linealis was caught in small numbers over a long period from October through to the end of the season, However, there was a seasonal peak in November 2016, somewhat earlier than the previous season. The increase in numbers was only to 58 individuals (n=5) collected predominantly at Bert Dix Memorial Park (R3). The raising and the receding of the river may have filled pools isolated from the main river channel and larger backwaters that have supported the reestablishment of emergent vegetation over the previous few years. These habitats are suitable larvae habitats for both these species. This reporting period 33 cases of arboviral infection have been attributed to the Renmark Paringa Council area (29 probable and 4 confirmed), all RRV and attributed to “Renmark” (Table 4.2). The majority of these cases had a date of onset from December 2016 through to February 2017. This represented an association with the increase in abundance of the vector species of major concern in inland Australia, Cx. annulirostris (Chart 5.5. This season the passive mosquito trap was again deployed, this season it was located at the Renmark Paringa Council building in the garden bed. Three FTA cards were exposed and no detections made. In additions to Passive traps, FTA cards were set in 40% of the EVS traps deployed in the council. In response to an RRV detection at Wellington Caravan Park (MB5), the number of FTA cards deployed in EVS traps was increased in subsequent field trips (Table 4.3). However, no detections were made within the Renmark Paringa Council

46 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 5. Results Renmark Paringa Council.

LOCAL RECOMMENDATIONS.

As with previous years, it is recommended that Cq. linealis should be controlled by source reduction in well-vegetated backwaters near the Riverfront Caravan Park and The Bert Dix Memorial Park as it poses a significant nuisance to residents in warmer months. Some investigation of possible sources of this species at the Renmark Golf Course in required, the dramatic increase in the abundance of this species in such an isolated location is of concern. Ae. camptorhynchus populations have increased over recent seasons, this species is an early season mosquito and an aggressive outdoor biter. It is proposed that known larvae sites of this species be monitored and targeted for late Autumn or winter control programs when appropriate to reduce the impact of the spring flushes of mosquitoes particularly near the Riverfront Caravan Park and The Bert Dix Memorial Park. The trial of the new Passive trap system should be continued and the response and implications of arboviral detections are established. Establish permanent S-Methoprene stations at known problem larva sites within the council, particularly for sites that are active annually. It is important to strive for the environmental health effects of environmental flows and wetland inundation is considered by water managers when planning. The mosquito communities’ response needs to be a consideration when undertaking these activities. Consulted of EHO’s and factored in the monitoring of the mosquito populations (both larva and adult) when conducting these activities is the ideal. Communication channels are having been developed but this is an ongoing issue and requires continual improvement; this will take some time to resolve as new water management practices evolve and health issues require consideration.

47 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

6. RESULTS FOR THE BERRI BARMERA COUNCIL. Adult trap site descriptions.

B1 Monash Playground

Longitude: E140 33.457 Latitude: S34 14.066

B2 Glossop Longitude: E140 31.597 Latitude: S34 16.126

48 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council.

B3 Martins Bend

Longitude: E140 37.858 Latitude: S34 17.360

B4 Berri Caravan Park

Longitude: E140 36.682 Latitude: S34 17.181

49 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council.

B5 Cobdogla

Longitude: E140 23.687 Latitude: S34 14.114

50 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council.

Weather Data: Berri Barmera Council.

Rainfall data were sourced from Bureau of Meteorology Weather Stations at Berri (Station number 24025), and Overland Corner (Station number 24012). Charts 6.1 and 6.2 show that precipitation was variable however, the total annual precipitation exceeded the long-term average precipitation at both Berri weather station (406.6 mm, 141.8 mm higher than historic mean of 264.8 mm), and Overland Corner weather station (348.3 mm was higher than the historic mean of 257.3 mm by 91 mm). Overall the Berri Barmera Council was wetter than or close to long term means over most of the season, however, September 2016, was far wetter than average with total precipitation recorded at both weather stations over four times long term trends. This was followed by relatively average precipitation during October and November. The Summer months were mostly wetter than long term trends with precipitation exceeding long-term means by at least 13 mm at both sites. There is no weather station that records temperatures within the Council area so temperatures can be inferred from The Renmark Aerodrome Station (Chart 5.1).

51 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council.

Chart 6.1. Total Monthly Precipitation (mm) at Berri Weather Station (24025) during the 2016-17 Trapping Period Compared with the Historic Mean. 120.00 Total precipitation Historic Mean

100.00

80.00

60.00

40.00 Precipitation(mm) 20.00

0.00 May June July August September October November December January February March April

Month

Chart 6.2. Total Monthly Precipitation (mm) at Overland Corner Weather Station (24012) during the 2016-17 Trapping Period Compared with the Historic Mean. 120.00 Total precipitation Historic Mean

100.00

80.00

60.00

40.00 Precipitation (mm) Precipitation

20.00

0.00 May June July August September October November December January February March April Month NOTE: Figures above run from May 2016, four months before the start of this sampling season.

52 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council. - Weather Data.

Adult mosquito trapping results: Berri Barmera Council. Chart 6.3. Berri Barmera Council Area, Total adult, Ae. annulirostris and Cx. australicus female mosquitoes caught in the 2016-17 season.

Chart 6.4. Berri Barmera Council Area, total and secondary species of adult mosquitoes caught in the 2016-17 season.

53 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council. - Adult Data.

Chart 6.5. Berri Barmera Council Area, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

54 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council. - Adult Data. Table 6.1. Totals for the five traps in Berri Barmera Council Area. Species 29/08/16 22/09/16 17/10/16 9/11/16 3/12/16 21/12/16 14/01/17 10/02/17 5/03/17 29/03/17 25/04/17 Season Total Ae. alboannulatus 0 0 0 0 1 0 0 0 0 0 3 4 Ae. camptorhynchus 94 118 186 812 673 30 10 0 0 0 0 1923 Ae. notoscriptus 14 0 0 0 7 0 1 1 0 0 1 24 Ae. postspiraculosis 0 0 1 0 0 0 0 0 0 0 0 1 Ae. sagax 1 2 0 21 148 2 0 0 0 0 6 180 An. annulipes 5 3 109 175 526 51 1 3 1 2 1 877 Cq. linealis 0 0 0 11 14 4 0 0 2 0 0 31 Cx. annulirostris 3 0 1 80 1321 1279 74 37 9 0 1 2805 Cx. australicus 0 147 4451 475 1026 14 2 0 10 1 1 6127 Cx. globocoxitus 0 0 59 44 18 3 2 0 0 0 5 131 Cx. molestus 12 5 2 9 7 0 0 0 2 2 5 44 Cx. quinquefasciatus 1 1 39 36 43 19 6 5 1 5 24 180 Tp. atripes 0 0 0 0 0 0 0 2 3 0 0 5 Unidentifiable 0 0 1 0 4 0 0 2 0 0 0 7 Male 0 0 0 0 5 0 0 0 0 0 0 5 no captures 1 1 0 0 0 1 0 0 0 1 0 4 Trap failure 1 1 0 1 0 2 1 0 0 0 0 6 Total Adults 130 276 4849 1663 3788 1402 96 50 28 10 47 12339 n=4 n=4 n=5 n=4 n=5 n=3 n=4 n=5 n=5 n=5 n=5 Total (n=49)

55 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council. - Adult Data. Table 6.2. Average Catch for the five traps in Berri Barmera Council Area.

Species 29/08/16 22/09/16 17/10/16 9/11/16 3/12/16 21/12/16 3/12/16 10/02/17 5/03/17 29/03/17 25/04/17 Ae. alboannulatus 0 0 0 0 0.2 0 0 0 0 0 0.6 SE 0 0 0 0 0.2 0 0 0 0 0 0.245 Ae. camptorhynchus 23.5 29.5 37.2 726 134.6 10 2.5 0 0 0 0 SE 18.976 20.759 17.238 70.23 75.834 6.807 1.541 0 0 0 0 Ae. notoscriptus 3.5 0 0 0 1.4 0 0.25 0.2 0 0 0.2 SE 0.866 0 0 0 0.748 0 0.224 0.2 0 0 0.2 Ae. postspiraculosis 0 0 0.2 0 0 0 0 0 0 0 0 SE 0 0 0.2 0 0 0 0 0 0 0 0 Ae. sagax 0.25 0.5 0 6 29.6 0.67 0 0 0 0 1.2 SE 0.25 0.289 0 3.351 14.958 0.333 0 0 0 0 0.374 An. annulipes 1.25 0.75 21.8 166 105.2 17 0.25 0.6 0.2 0.4 0.2 SE 0.25 0.479 11.633 11.877 52.657 8.505 0.224 0.4 0.2 0.245 0.2 Cq. linealis 0 0 0 11 2.8 1.33 0 0 0.4 0 0 SE 0 0 0 2.428 2.557 1.333 0 0 0.245 0 0 Cx. annulirostris 0.75 0 0.2 79 264.2 426.33 18.5 7.4 1.8 0 0.2 SE 0.25 0 0.2 8.851 178.561 262.7 10.304 3.6 0.916 0 0.2 Cx. australicus 0 36.75 890.2 215 205.2 4.67 0.5 0 2 0.2 0.2 SE 0 19.572 378.886 58.631 47.732 4.667 0.447 0 2 0.2 0.2 Cx. globocoxitus 0 0 11.8 24 3.6 1 0.5 0 0 0 1 SE 0 0 6.967 3.697 1.288 1 0.274 0 0 0 1 Cx. molestus 3 1.25 0.4 2 1.4 0 0 0 0.4 0.4 1 SE 1.78 0.629 0.245 1.601 1.166 0 0 0 0.4 0.4 0.775 Cx. quinquefasciatus 0.25 0.25 7.8 22 8.6 6.33 1.5 1 0.2 1 4.8 SE 0.25 0.25 4.054 5.447 5.564 5.84 0.895 1 0.2 1 2.635 Tp. atripes 0 0 0 0 0 0 0 0.4 0.6 0 0 SE 0 0 0 0 0 0 0 0.4 0.6 0 0 Unidentifiable 0 0 0.2 0 0.8 0 0 0.4 0 0 0 Trap failures 0 0 0.2 0 0.374 0 0 0.4 0 0 0 Male 0 0 0 0 1 0 0 0 0 0 0 SE 0 0 0 0 1 0 0 0 0 0 0 no captures 1 1 0 0 0 1 0 0 0 1 0 Trap failure 1 1 0 1 0 2 1 0 0 0 0 Total Adults 32.5 69 969.8 1251 757.6 467.33 24 10 5.6 2 9.4 SE 17.217 15.286 380.03 39.645 275.67 278.927 12.572 3.332 1.939 1.049 3.414 n=4 n=4 n=5 n=4 n=5 n=3 n=4 n=5 n=5 n=5 n=5

56 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. - Lara

Mosquito Larval Dipping and Treatment: Berri Barmera Council

Table 6.3. Results of Larval Dipping within Berri Barmera Council.

australicus

globocoxitus

Cx.

Site Condition Site Larvae present Larvae Site Trip Date camptorhynchus Ae. Density B4L4 1 27/8/2016 Full Yes * High B5L5 1 27/8/2016 Full Yes * Low B3L2 2 22/9/2016 Full No B3L6 2 22/9/2016 Full No B4L17 2 22/9/2016 Receding No B5L13 2 22/9/2016 Full Yes * High B1L1 3 17/10/2016 Full Yes * Medium B3L1 3 17/10/2016 Filling Yes * High B3L7 3 17/10/2016 Filling No B4L4 3 17/10/2016 Full No B5L3 3 16/10/2016 Full No B3L1 4 10/11/2016 Full Yes * High B3L1 5 3/12/2016 Filling Yes * Low B3L3 5 3/12/2016 Filling No B3L7 5 3/12/2016 Filling No B3L8 5 3/12/2016 Filling No B3L11 5 3/12/2016 Filling No B4L8 5 3/12/2016 Filling No B4L17 5 3/12/2016 Filling No B5L5 5 3/12/2016 Full No B5L7 5 3/12/2016 Full No B5L10 5 3/12/2016 Full No B5L12 5 3/12/2016 Full No B5L13 5 3/12/2016 Full No B4L8 6 21/12/2016 Full No B3L7 7 14/1/2017 Receding No B3L8 7 14/1/2017 Receding No B3L11 7 14/1/2017 Receding No B3L7 7 14/1/2017 Receding No B4L4 7 14/1/2017 Receding No B4L8 7 14/1/2017 Receding No B4L17 7 14/1/2017 Receding No B4L19 7 14/1/2017 Receding No B4L23 7 14/1/2017 Receding No B5L5 7 14/1/2017 Full No B5L7 7 14/1/2017 Full No B5L8 7 14/1/2017 Full No B5L10 7 14/1/2017 Receding No

57 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results Berri Barmera Council. Berri Barmera larvicide treatments.

The dramatic change in conditions experienced several years age continue to influence the mosquito community in the upper River Murray. As with the previous season, many of larvae sites previously identified did not require treatment. In September 2016, some pre-emptive treatment of known Ae. camptorhynchus sites were undertaken (Table 6.4). The heavy summer rainfall during September resulted in increased effort to identify active and potential larvae sites during September and October. Several active sites were found and treated (Tables 6.3 & 6.4). Fortunately, the increases spring precipitation coincided with unseasonably cooler weather resulting in conditions suitable for Cx. australicus, there was also an increase in the cool weather Aedes species Ae. camptorhynchus. This was not the case in the Renmark Paringa Council where the larvae sites were accessible and effectively treated. Interestingly the council also had a large cohort of the vector species Cx. annulirostris during December, primarily around the Berri Caravan Park (B4) and Cobdogla (B5). This is problematic as potential larvae sites are difficult to access and the increase may be related to the unregulated flow inundating shallow pools around Martins Bane and Cobdogla. Shallow pools are both difficult to access and tend to be difficult for predators such as fish to access and control larvae. Monitoring of larvae sites continued over the remaining part of the season along with the investigation of potential new sites and additional pre-emptive deployment of S-Methoprene briquettes during April and May 2016.

58 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. – Larvae Data. Table 6.4. Larvicide application in Berri Barmera Council during the 2016-17 season.

Site Date Product Quantity B3L1 14/5/2016 Briquettes 3 B3L3 14/5/2016 Briquettes 7 B2L7 14/5/2016 Briquettes 3 B3L11 14/5/2016 Briquettes 2 B3L16 14/5/2016 Briquettes 5 B4L8 14/5/2016 Briquettes 5 B4L9 14/5/2016 Briquettes 4 B4L10 14/5/2016 Briquettes 13 B4L14 14/5/2016 Briquettes 5 B4L4 27/8/2016 Briquettes 4 B5L5 27/8/2016 Briquettes 6 B1L1 22/9/2016 Briquettes 2 B1L2 22/9/2016 Briquettes 2 B1L3 22/9/2016 Briquettes 15 B3L10 22/9/2016 Briquettes 1 B3L14 22/9/2016 Briquettes 1 B5L13 22/9/2016 Briquettes 6 B1L3 17/10/2016 Briquettes 19 B3L1 17/10/2016 Briquettes 6 B4L4 17/10/2016 Briquettes 4 B4L14 17/10/2016 Briquettes 3 B5L3 16/10/2016 Briquettes 3 B3L1 10/11/2016 Briquettes 10 B3L3 10/11/2016 Briquettes 5 B5L12 3/12/2016 Briquettes 1 B1L2 25/4/2017 Briquettes 13 B1L3 25/4/2017 Briquettes 1 B2L8 25/4/2017 Briquettes 3 B3L1 25/4/2017 Briquettes 7 B3L3 25/4/2017 Briquettes 4 B3L16 25/4/2017 Briquettes 3 B4L4 25/4/2017 Briquettes 3 B4L8 25/4/2017 Briquettes 4 B4L16 25/4/2017 Briquettes 2 B5L2 25/4/2017 Briquettes 3 B5L5 25/4/2017 Briquettes 18 B5L7 25/4/2017 Briquettes 4 B5L8 25/4/2017 Briquettes 9 B5L13 25/4/2017 Briquettes 5

59 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. Discussion of Berri Barmera results.

Adult Mosquito. A total of 12, 339 (n=49) adult mosquitoes were trapped in the Berri Barmera Council Area during the 2016-17 season; the third highest catch since the commencement of this program (Table 6.5). This was a dramatic change from the previous season which recorded only 314 mosquitoes (n=51) the lowest mosquito numbers since the commencement of the program in 1999. This was almost 50 times the number of mosquitoes caught in the previous season corrected for sample size. This increase in mosquito numbers is likely to be caused by similar mechanisms as in the other two upper river councils. This is a dramatic change from the previous three seasons which recorded some of the lowest mosquito numbers since the commencement of the River Murray surveillance program. This was the just over half the record number of mosquitoes caught during the record season of 2010-11 when 24, 458 (n=53) mosquitoes were trapped [9]. During the 2016- 17 season, the average mosquito caught per trap night was a staggering ≈252 a dramatic increase from the previous season (≈6.16) and well above the historic mean for the Council (≈87). Overall Mosquito numbers were slightly above average in September then increased dramatically through October due to large numbers of Cx. australicus. Overall numbers then dropped by around a third in November 2016 as Cx. australicus decreased and Ae. camptorhynchus reached its peak (Chart 6.5). Then through December as the unregulated flow event reached its zenith mosquito numbers peaked again this event coincided with large numbers of Cx. annulirostris. The structure of the mosquito populations in the council was quite complex this season particularly in the first half of the season with three overlapping species forming a prolonged period of elevated mosquito numbers. From a human health and disease perspective, each of the species presents a different concern. mosquitoes caught this season the mosquito community was less diverse in regards to species richness this was mainly due to around half (49.7 %) of all individuals caught belonging to the species Cx. australicus. Of the remaining catch both Cx. annulirostris and Ae. camptorhynchus were well represented making up around 22.7 % and 15.6 % of the total mosquito catch. The remainder of the mosquito species identified where diverse being made up of the following species in order of descending abundance An. annulipes (7.1%), Ae. sagax (1.46 %), Cx. quinquefasciatus (1.46 %), Cx. globocoxitus (1.06 %), The remaining species only contributed a few individuals (<0.5%) to the total mosquito catch (Table 6.1).

60 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. - Discussion. Species worthy of consideration include:

Cx. australicus (6,127, or 49.7% of total catch) this species was clearly the most dominant species over the 2016-17 season. This is most interesting as historically this species has contributed less than 4% to the overall mosquito catch over 17 years of surveillance. The number of individuals caught is around twice the total number of this species caught in Berri Barmera Council over the life of this program (3, 230 n=877). Cx. australicus had a bi-modal peak in abundance with a dip in abundance over November that may have been due to stochastic events. Cx. australicus was caught across all trap locations within the council but numbers did vary at each location. This species was most common at the Monash Playground site (B4) where 42 % of all individuals of this species were caught and it represented over 90 % of all individuals caught at this site. The Berri Caravan Park (B4) was the location with the second highest number of Cx. australicus this season with 34 % of all individuals (2, 549) caught this season coming from this location. Cx. australicus was also relatively common at this location, comprising over half (52.4 %) of all individuals from traps set at this location. Significant numbers were also caught at Cobdogla (851) and Glossop, (595) representing 86.3 % and 22.2 % of the catch at these locations. Strangely only 48 individuals were caught at Martins Bend (B3) which is only a short distance from The Berri Caravan Park (B4) Cx. annulirostris (2, 805, or 22.7% of total catch) was the second most abundant mosquito species over the 2016-17 season in the Berri Barmera Council, a major increase in both the overall and relative abundance in the previous season (27, or 8.6% of total catch). This species is thought to be the major vector of arboviral disease in the Riverland area during warmer months. Cx. annulirostris occurred throughout the season, with the highest numbers being recorded in December with 1, 321 (n=5) and 1, 279 (n=3) individuals caught (Chart 6.3). Cx. annulirostris was not distributed evenly across the council, with around 44 % of all individuals caught at The Berri Caravan Park (B4) and the majority of the remainder (38 %) coming from Cobdogla (39.4 % of mosquitoes at this site). Martins Bend also had a large number of Cx. annulirostris caught at this location with 504 individuals identified from this location, this was 18 % of the total species catch. The other locations recorded only 10 or fewer individuals. Ae. camptorhynchus (1, 923, or 15.6 % of total catch) was the third most abundant species within the Berri Barmera Council over the 216-17 season. This compares to a historic seasonal average of 33.5% of mosquitoes trapped in Berri Barmera Council over the previous 17 years of monitoring. The lack of individuals over the previous seasons is thought to be due to the egg bank being removed during the high river in 2010/11. From 2011-13 this pattern was repeated at all

61 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. - Discussion. adult trap sites north of Mannum. However, in the 2013-14 season, several larvae sites with the high densities were discovered in the adjacent council Renmark Paringa. This species increased in overall numbers from only 66 in the previous season to 1, 923 individuals in 2016-17, but decreased as a proportion of the total mosquito catch from 21% to only 15.6% of the total mosquito catch. Ae. camptorhynchus had a peak in abundance in November and into early December 2016. This was somewhat later than the historic peaks which tend to occur during October and November. Following, the high numbers caught up until December numbers then quickly declined to only 10 individuals caught in January 2017 then no more after that. This species was distributed across all locations within the council but unequally with the highest number 863 caught at Martins Bend (B3), this was approximately 45 % of all the individuals of this species caught within the council this season. The location with the second highest number of Ae. camptorhynchus was Cobdogla (B5) where 604 individuals were caught this was 31.4 % of the all the Ae. camptorhynchus caught this season. The location with the third highest number of Ae. camptorhynchus was The Berri Caravan Park (B4) where 342 individuals or 18 % of all individuals of this species caught within the council over the 206-17 season. Only a small number of individuals were caught at the remaining locations. An. annulipes (877, or 7.11% of total catch) was the fourth most common species collected during the 2016-17 season. This species also had a well-defined early season peak in abundance, and the species was caught across all located within the council with most individuals caught at Martins Bend (B3) and Cobdogla (B5). Ae. sagax (180, or 1.46% of total catch) this species was caught throughout the season but the Majority of individuals were caught in early December. The majority of individuals were identified from Martins Bens (B3) and Berri Caravan Park (B4) where large cohorts occurred in December at both locations.

62 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. - Discussion. Table 6.5. Summary of previous monitoring seasons, Berri Barmera Council. FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/ 2003 2003/ 2004 2004/ 2005

Rainfall Heavy, February Light, December. Sept. fall & then dry Sept. rain, then very dry Average early, very dry later Peaks in Aug & Dec/Jan River Levels No data Peaks, Oct and Dec. Small November peak No peak Elevated in September No large elevations Total female Mosquitoes 6, 572 (n=43) 8, 350 (n=54) 622 (n=51) 600 (n=50) 1, 885 (n=55) 1, 609 (n=55) Mosquito Peak March October October February November Sept/ Jan Ae. camptorhynchus, Cx. quinquefasciatus Dominant Species Cx. annulirostris Ae. camptorhynchus Ae. camptorhynchus Cx. molestus, Cx. quinquefasciatus. Ae. camptorhynchus & Cx. annulirostris. Reported arbovirus infections ~25 (RRV) ~5 (RRV) ~2 (RRV) None confirmed ~1 (RRV) ~2 (RRV)

FEATURE 2005/ 2006 2006/ 2007 2007/ 2008 2008/ 2009 2009/ 2010 2010/ 2011

Average peaks in Sept/ Very wet December, Above Rainfall wet winter, dry summer Low, Jan, March-April peaks Low Spring /high Summer Peak in Aug, Nov/Dec Nov/March average rainfall No extraordinary peaks Summer Raised Lock 4 raised from Aug/ Nov, River Levels No extraordinary peaks No extraordinary peaks downstream pool levels peak in Feb Total female Mosquitoes 13, 060 (n=51) 1. 658 (n=54) 598 (n=51) 1, 228 (n=43) 1, 329 (n=54) 24, 432 (n=53) Mosquito Peak Oct/Nov, Feb/March September/ November November/ March September October/ March Early January Ae. camptorhynchus/ Ae. camptorhynchus/ Ae. camptorhynchus/ Ae. camptorhynchus/ Dominant Species Ae. camptorhynchus/ Cx. molestus Ae. camptorhynchus Cq. linealis Cx. quinquefasciatus/ Cq. linealis Cx. molestus/ Cx. annulirostris Cx. annulirostris Reported arbovirus infections ~18 (RRV) 2 (RRV) 7 (RRV), 2 (BFV) 7 (RRV) 10 (RRV) 70 (RRV), 14 (BFV), 1 (MVE)

FEATURE 2011/ 2012 2012/ 2013 2013/14 2014/15 2015/16

Rainfall Higher than Average Oct-Jan, & March above average Feb /July Feb rain event Early January rain event January rain event Variable, High until October, January Variable river levels downstream Water level raised upstream of locks in River Levels raised downstream of Lock raised downstream of locks in spring pulse, flood in April. of locks spring Total female Mosquitoes 2, 439 (n=50) 1, 994 (n=51) 682 (n=51) 856 (n=51) 314 (n=51) Mosquito Peak April October/ January /March No real peak August/September No real peak Dominant Species Cx. annulirostris/ Cx. australicus Cx. annulirostris Cx. quinquefasciatus/ Cx. annulirostris Ae. camptorhynchus/ Cx. quinquefasciatus Ae. camptorhynchus/ Cx. quinquefasciatus Reported arbovirus infections 6 (RRV), 5 (BFV) 3 (RRV), 4 (BFV) 7 (RRV) 7 (RRV) 6 (RRV), 1 (BFV)

63 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. - Discussion. Summary of previous monitoring seasons, Berri Barmera Council (cont.).

FEATURE 2015/16

Rainfall September rain event River Levels Unregulated flow late 2016 Total female Mosquitoes 12, 339 (n=49) Mosquito Peak October & December Dominant Species Cx. australicus/ Cx. annulirostris Reported arbovirus infections 32 (RRV, 27 probables, 5 confirmed)

64 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. COMMENTS. This season recorded the third highest number of mosquito since the commencement of this monitoring program with only 12, 339 (n=49), compared to the historic season mean of 3, 575.2 mosquitoes (corrected for n=51) and median of 1, 592 (n=55). Like the other two upper River Murray Council, the dominant mosquito species within the Berri Barmera Council was Cx. australicus comprising 49.7 % of all individuals caught. During the 2016-17 season, the mosquito community was concentrated across the earlier part of the season, this bi-modal peak in abundance was complex with a number of species contributing. The majority of mosquitoes caught in October (92%) belonged to the species Cx. australicus (Chart 6.3), as the season warmed the community became increasingly diverse with Ae. camptorhynchus, Cx. annulirostris, An. annulipes and Ae. sagax all contributing to the overall mosquito catch (Chart 6.4). The distribution of mosquitos across the 2016-17 season appears to be similar to historic patterns (Chart 6.5) albeit with far higher numbers. It is worth noting that the observed drop in numbers during November could be due to stochastic variation. The structure of the mosquito community differed from historic patterns with the early season dominated by Cx. australicus rather that the cool weather mosquito Ae. camptorhynchus. Ae. camptorhynchus has been an important component of the mosquito community along the River Murray this was disrupted during the high river of 2010-11. Following this event, there was a prolonged period of low populations of Ae. camptorhynchus thought to be due to the egg bank being depleted following the prolonged submergence of the floodplain over the 2010-11 season[9]. Populations of the spring mosquito Ae. camptorhynchus were restricted both temporally but were more widespread than the previous season when the majority were retrieved from Martins Bend (65%). This season the Ae. camptorhynchus was found in numbers at all near river sites. The second peak in occurring in December had a high number of the major arboviral vector Cx. australicus (Chart 6.3), the increase in the population of this species is of concern as it is considered to be a major vector of arbovirus in inland Australia. Cx. annulirostris has the capacity to rapidly increase in numbers following heavy rain events, it is interesting that the population of this species then crashed into the new year despite the above average rain recorded in January and February 2017. Monitoring and treatment of larvae sites became more intensive following a heavy the high rainfall recorded over September 2017. The effort was tempered by the late season deployment of Briquettes at known problem sites during May 2016 and on that last collection trip of the previous season Table 6.4. The unregulated flow event that occurred in the latter

65 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results for the Berri Barmera Council. half of 2016 undoubtedly had an effect on mosquito abundance. These events are difficult to control particularly around areas such as Martins Bend and Cobdogla which tend to have large areas of flat floodplain which are inundated creating large areas of potential larvae habitat that are difficult to access. The wet floodplain is also of concern as any large rain events present a high risk as the resulting pools are suitable for the major vector species Cx. annulirostris which can rapidly increase in numbers. This is of concern in the upper river as Fortunately, there was no increase in the numbers of Cx. annulirostris identified in response to rain in late December through to February. Interestingly as with the previous season the domestic pest species Ae. notoscriptus was only caught in negligible numbers. This is curious as historically this species has consistently contributed to over 5% of the total female mosquito catch, and is suited to the prevailing weather conditions. In the Berri Barmera Council, there were 32 cases of RRV reported over the 2016-17, one in July 2015 (27 Probable, 5 Confirmed). There was a seasonal increase in the number of reported cases of probable and confirmed cases of RRV with a date of onset in December 2016. The number of reported infections remained elevated through February 2017, then declined towards the end of the season.

66 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 6. Results: Berri Barmera Council. LOCAL RECOMMENDATIONS.

The population of Ae. camptorhynchus increased to become a significant component of the mosquito fauna within the Berri Barmera Council (≈15.6 %), this species is a cool weather mosquito and an aggressive outdoor biter. In previous years this species has been a significant pest within the council particularly around spring. It is presumed that the egg bank of this species was depleted due to the flooding event of early 2011. It is proposed that known larvae sites of this species be monitored and targeted for a winter control programs when appropriate to reduce the impact of the spring flushes of mosquitoes. The trial of the new FTA Cards system should be continued and the response and implications of arboviral detections be established Establish permanent S-Methoprene stations at known problem larva sites within the council, particularly for sites that are active annually. It is important to strive for the environmental health effects of environmental flows and wetland inundation is considered by water managers when planning. The mosquito communities’ response needs to be a consideration when undertaking these activities. Consulted of EHO’s and factored in the monitoring of the mosquito populations (both larva and adult) when conducting these activities is the ideal. Communication channels are having been developed but this is an ongoing issue and requires continual improvement; this will take some time to resolve as new water management practices evolve and health issues require consideration.

67 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

7. RESULTS FOR THE DISTRICT COUNCIL OF LOXTON WAIKERIE. Adult trap site Descriptions.

L1 Loxton Golf Course Longitude : E140 38.939 Latitude: S34 25.530

L2 Loxton Caravan Park Longitude: E140 33.089 Latitude: S34 26.913

68 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. L3 Moorook Longitude: E140 22.090 Latitude: S34 17.357

L4 Kingston Longitude: E140 21.011 Latitude: S34 13.363

69 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. L5 Waikerie Longitude: E140 33.460 Latitude: S34 14.068

70 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. Weather Data: The District Council of Loxton Waikerie.

Seasonal temperatures from the Loxton Weather Station (24024) are presented in Chart 7.1. Overall the season featured warmer than average daily maximum and minimum temperatures over Winter, Summer and Autumn. During Spring average daytime temperatures fell short of the seasonal average by 1 °C while night-time temperatures were around 0.5 °C cooler than long term trends. Daytime temperatures were the coolest relative to the long-term mean of 20.8 °C during September with monthly average maximum temperatures of only 18.9 °C. Over the remaining period, daily maximum temperatures had the greatest deviation from long-term trends was recorded in March 2017 where it exceeded long-term trends by 2.8 °C. The average daily minimum temperatures or night time temperatures like the daytime temperatures were cooler than long-term trends during spring, however, they were slightly above or well average over the remainder of the season at Loxton Weather Station. October and November, in particular, had daily minimum temperatures lower than what would be expected based on historical data. Over January and March, 2017 daily minimum temperatures were over a degree hotter than long term trends would suggest (Chart 7.2). The 14DMADMin did not exceed 15 ºC until late December 2016. Following this nights remained essentially as warm or slightly warmer until the second week of February 2016, where the 14DMADMin fell below 15 ºC and remained so for around two and a half weeks. Following this period of cooler nights, the 14DMADMin rose above 15 ºC and remained so for a further two times. Each of these periods lasted around a week each separated by a slightly cooler period of four days before declining again and remaining below this level for the remainder of the season. (Chart 7.1). The 14DMADMax first exceeded 25 ºC from the last few days of October 2016 through to the first week of April 2017. During this period, the 14DMADMax exceeded 30 ºC, over two periods; the first period lasted 9 weeks from mid-December through to mid- February 2017. The temperature then dropped slightly below 30 ºC for 4 days the rose to exceed this temperature for a further four and a half weeks until late March 2017. During this period, the 14DMADMax did not exceed 35 ºC. Precipitation was recorded at Loxton Weather Station (24024, Chart 7.3) and Waikerie Council Works Depot Weather Station (24038, Chart 7.4). The total annual precipitation to May 2017 at Loxton Weather Station (400.8 mm) was over double recorded over the previous period 193.9 mm below the historic mean (130.4 mm). The Waikerie Council Works Depot recorded a much wetter season than the previous season with over three times the precipitation

71 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Weather Data recorded for the same period 324.2 mm compared to 108.4 mm (over 2015-16) and exceeding the historic mean by 55.1 mm (historic mean of 269.1 mm). The data from the second site is not of good quality with data only recorded since 2001 and many periods of missing data, therefore it is not indicative of long term trends in this area.

72 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Weather Data Chart 7.1. Loxton Research Centre Weather Station (24024) Maximum and Minimum Temperature 14-day Moving Average from May 2015 to April 2016.

C ° 20

15 Temperature

0 1/05/16 1/06/16 1/07/16 1/08/16 1/09/16 1/10/16 1/11/16 1/12/16 1/01/17 1/02/17 1/03/17 1/04/17 Date

Chart 7.2. Loxton Research Centre Weather Station (24024) Monthly Mean Maximum and Minimum Temperature May 2016 to April 2017 compared to historic means (solid line). 35 Mean max temp 2016-17 Historic mean Mean min temp 2016-17 Historic min

C °

15 Temperature Temperature

0 May June July August September October November December January February March April Month 73 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Weather Data Chart 7.3. Total Monthly Precipitation (mm) at Loxton Research Station Weather Station (24024) during the 2016-17 Trapping Period Compared with the Historic Mean.

120 Total precipitation Historic Mean

100

Precipitation (mm) Precipitation 40

0 May June July August September October November December January February March April Month

Chart 7.4. Total Monthly Precipitation (mm) at Waikerie Council Works Depot Weather Station (24038) during the 2016-17 Trapping Period Compared with the Historic Mean. 100 Total precipitation Historic Mean

Precipitation (mm) Precipitation 30

0 May June July August September October November December January February March April Month

NOTE: Figures above run from May 2016, four months before the start of this sampling season.

74 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Adult Data. Adult mosquito trapping results: The District Council of Loxton Waikerie. Chart 7.5. Loxton Waikerie Council Area, total Cx. australicus and An. annulipes female adult mosquitoes caught in the 2016-17 season.

Chart 7.6. Loxton Waikerie Council Area, total and secondary species of adult mosquitoes caught in the 2016-17 season.

75 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. Chart 7.7. Loxton Waikerie Council Area, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

76 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. Adult Data Table 7.1. Totals for the five traps in Loxton Waikerie Council Area.

Species 29/08/16 22/09/16 17/10/16 9/11/16 3/12/16 21/12/16 14/01/17 10/02/17 5/03/17 29/03/17 25/04/17 Season Total Ae. alboannulatus 0 0 2 0 4 0 0 0 0 0 0 6 Ae. camptorhynchus 16 33 23 284 15 2 2 0 0 0 0 375 Ae. eidsvoldensis 0 0 0 1 0 0 0 0 0 0 0 1 Ae. notoscriptus 3 0 0 6 25 3 3 0 0 1 0 41 Ae. sagax 0 3 0 33 4 0 0 0 0 0 14 54 Ae. tremulus 0 0 0 0 0 0 0 1 0 0 0 1 An. annulipes 7 1 88 757 121 113 11 40 2 5 2 1147 Cq. linealis 0 0 1 0 0 0 0 0 0 0 1 2 Cx. annulirostris 7 0 9 107 109 148 130 22 4 4 0 540 Cx. australicus 2 59 683 685 211 143 2 0 0 1 0 1786 Cx. globocoxitus 0 3 9 69 2 0 1 0 0 0 2 86 Cx. molestus 1 1 243 11 5 2 16 0 3 0 2 284 Cx. quinquefasciatus 0 1 0 8 28 0 2 2 0 1 0 42 Tp. atripes 0 0 0 0 0 0 1 0 0 0 0 1 Unidentifiable 0 2 0 3 0 0 0 0 0 0 0 5 Male 0 2 0 5 0 0 6 0 0 0 0 13 Total Adults 36 103 1058 1964 524 411 168 65 9 12 21 4371 n=4 n=5 n=5 n=4 n=5 n=5 n=5 n=5 n=5 n=5 n=5 Total (n=53)

77 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Adult Data. Table 7.2. Average Catch for the five traps in Loxton Waikerie Council Area.

Species 29/08/16 22/09/16 17/10/16 9/11/16 3/12/16 21/12/16 14/01/17 12/02/15 5/03/17 29/03/17 25/04/17 Ae. alboannulatus 0 0 0.4 0 0.8 0 0 0 0 0 0 SE 0 0 0.894 0 1.304 0 0 0 0 0 0 Ae. camptorhynchus 4 6.6 4.6 71 3 0.4 0.4 0 0 0 0 SE 3.559 10.383 5.177 58.912 2.739 0.548 0.894 0 0 0 0 Ae. eidsvoldensis 0 0 0 0.25 0 0 0 0 0 0 0 SE 0 0 0 0.5 0 0 0 0 0 0 0 Ae. notoscriptus 0.75 0 0 1.5 5 0.6 0.6 0 0 0.2 0 SE 1.5 0 0 2.38 10.63 1.342 0.894 0 0 0.447 0 Ae. sagax 0 0.6 0 8.25 0.8 0 0 0 0 0 2.8 SE 0 0.894 0 13.889 1.304 0 0 0 0 0 2.588 Ae. tremulus 0 0 0 0 0 0 0 0.2 0 0 0 SE 0 0 0 0 0 0 0 0.447 0 0 0 An. annulipes 1.75 0.2 17.6 189.25 24.2 22.6 2.2 8 0.4 1 0.4 SE 2.363 0.447 24.966 257.496 31.894 15.421 2.95 11.045 0.894 1 0.548 Cq. linealis 0 0 0.2 0 0 0 0 0 0 0 0.2 SE 0 0 0.447 0 0 0 0 0 0 0 0.447 Cx. annulirostris 1.75 0 1.8 26.75 21.8 29.6 26 4.4 0.8 0.8 0 SE 0.957 0 4.025 42.906 26.827 20.007 29.129 6.656 1.095 1.304 0 Cx. australicus 0.5 11.8 136.6 171.25 42.2 28.6 0.4 0 0 0.2 0 SE 0.577 12.578 235.848 217.742 33.641 37.058 0.894 0 0 0.447 0 Cx. globocoxitus 0 0.6 1.8 17.25 0.4 0 0.2 0 0 0 0.4 SE 0 0.894 1.643 27.861 0.548 0 0.447 0 0 0 0.894 Cx. molestus 0.25 0.2 48.6 2.75 1 0.4 3.2 0 0.6 0 0.4 SE 0.5 0.447 67.807 5.5 1.732 0.894 7.155 0 1.342 0 0.894 Cx. quinquefasciatus 0 0.2 0.2 2 5.6 0 0.4 0.4 0 0.2 0 SE 0 0.447 0 2.708 7.232 0 0.548 0.548 0 0.447 0 Unidentifiable 0 0.4 0 0.75 0 0 0 0 0 0 0 SE 0 0.894 0 1.5 0 0 0 0 0 0 0 Male 0 0.4 0 1.25 0 0 1.2 0 0 0 0 SE 0 0.894 0 2.5 0 0 2.683 0 0 0 0 no captures 0 0 0 0 0 0 0 0 3 2 0 Trap failures 1 0 0 1 0 0 0 0 0 0 0 Total Adults 9 20.6 211.6 491 104.8 82.2 33.6 13 1.8 2.4 4.2 SE 4.967 16.95 215.367 562.51 69.962 49.327 41.35 16.016 3.033 2.302 2.28 n=4 n=5 n=5 n=4 n=5 n=5 n=5 n=5 n=5 n=5 n=5

78 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. Mosquito Larval Dipping and Treatment: Loxton Waikerie Council.

Table 7.3. Results of Larval Dipping within Loxton Waikerie Council.

australicus

globocoxitus

Ae. sagax Ae.

quinquefasciatus

Cx.

Unidentifiable

Site Condition Site Cx.

Larvae present Larvae

Ae. camptorhynchus Ae. Cx. Site Trip Date Density L2L8 1 27/8/2016 Full Yes * * High L2L18 1 27/8/2016 Full Yes * Medium L2L22 1 27/8/2016 Full Yes * Medium L5L6 1 27/8/2016 Filling No L5L8 1 27/8/2016 Full Yes * High L2L5 2 22/9/2016 Full Yes * Low L2L6 2 22/9/2016 Full Yes * Medium L2L12 2 22/9/2016 Full Yes * Medium L3L6 2 22/9/2016 Full Yes * * Medium L4L2 2 22/9/2016 Full Yes * High L4L3 2 22/9/2016 Receding No L4L4 2 22/9/2016 Full Yes * Low L4L5 2 22/9/2016 Full Yes * Medium L4L6 2 22/9/2016 Full Yes * High L4L7 2 22/9/2016 Full Yes * High L5L6 2 22/9/2016 Full Yes * High L5L10 2 22/9/2016 Full Yes * * High L1L8 3 17/10/2016 Full No L2L1 3 17/10/2016 Full Yes * * High L2L4 3 17/10/2016 Full Yes * Low L2L5 3 17/10/2016 Full Yes * * High L2L6 3 17/10/2016 Full Yes * * High L2L11 3 17/10/2016 Full Yes * * High L4L8 3 17/10/2016 Full Yes * High L4L9 3 17/10/2016 Full Yes * High L4L10 3 17/10/2016 Full Yes * High L4L11 3 17/10/2016 Full Yes * High L4L12 3 17/10/2016 Full Yes * High L4L13 3 17/10/2016 Full Yes * High L4L14 3 17/10/2016 Full Yes * High L4L15 3 17/10/2016 Full Yes * High L4L16 4 10/11/2016 Full Yes * * Medium L4L17 4 10/11/2016 Full Yes * * Medium L1L8 5 3/12/2016 Full No L5L10 5 3/12/2016 Receding No L4L2 6 21/12/2016 Full No L4L3 6 21/12/2016 Full No L4L4 6 21/12/2016 Filling No L4L6 6 21/12/2016 Full No L4L7 6 21/12/2016 Full No L2L6 7 14/1/2017 Receding No L4L2 7 14/1/2017 Full No L4L3 7 14/1/2017 Full No L4L4 7 14/1/2017 Filling No L4L6 7 14/1/2017 Full No L4L7 7 14/1/2017 Full No

79 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. Loxton Waikerie Larvicide Treatments. The dramatic change in conditions experienced several years age continue to influence the mosquito community in the upper River Murray. At the end of the previous season and in May 2016 pre-emptive treatment of known Ae. camptorhynchus larvae sites were undertaken[7], this was reinforced with treatments in August 2016 (Table 7.4). In expectation of significant rain occurring in late September application of control measures continued into September particularly sites suitable for larvae of Ae. camptorhynchus and Cx. annulirostris. Monitoring of larvae sites continued over the remaining part of the season along with the investigation of potential new sites and additional pre-emptive deployment of S-Methoprene briquettes particularly at the end of the season.

Table 7.4. Larvicide application in Loxton Waikerie Council during the 2016-17 season.

Site Date Product Quantity Site Date Product Quantity L2L2 14/5/2016 Briquettes 7 L2L5 17/10/2016 Briquettes 32 L5L3 14/5/2016 Briquettes 1 L2L6 17/10/2016 Briquettes 14 L5L6 14/5/2016 Briquettes 5 L2L11 17/10/2016 Briquettes 8 L5L8 14/5/2016 Briquettes 5 L4L8 17/10/2016 Briquettes 1 L5L9 14/5/2016 Briquettes 5 L4L9 17/10/2016 Briquettes 1 L5L13 14/5/2016 Briquettes 2 L4L10 17/10/2016 Briquettes 1 L5L14 14/5/2016 Briquettes 2 L4L11 17/10/2016 Briquettes 1 L2L2 27/8/2016 Briquettes 9 L4L12 17/10/2016 Briquettes 1 L2L8 27/8/2016 Briquettes 6 L4L13 17/10/2016 Briquettes 1 L2L18 27/8/2016 Briquettes 3 L4L14 17/10/2016 Briquettes 1 L2L22 27/8/2016 Briquettes 4 L4L15 17/10/2016 Briquettes 1 L5L6 27/8/2016 Briquettes 4 L4L15 10/11/2016 Briquettes 1 L5L8 27/8/2016 Briquettes 5 L4L16 10/11/2016 Briquettes 1 L5L13 27/8/2016 Briquettes 1 L4L17 10/11/2016 Briquettes 1 L2L5 22/9/2016 Briquettes 4 L2L1 25/4/2017 Briquettes 12 L2L6 22/9/2016 Briquettes 10 L2L2 25/4/2017 Briquettes 15 L2L12 22/9/2016 Briquettes 10 L2L5 25/4/2017 Briquettes 16 L3L6 22/9/2016 Briquettes 2 L2L11 25/4/2017 Briquettes 6 L4L2 22/9/2016 Briquettes 12 L2L12 25/4/2017 Briquettes 16 L4L3 22/9/2016 Briquettes L2L18 25/4/2017 Briquettes 8 L4L4 22/9/2016 Briquettes 4 L2L20 25/4/2017 Briquettes 5 L4L5 22/9/2016 Briquettes 4 L4L2 25/4/2017 Briquettes 10 L4L6 22/9/2016 Briquettes 1 L4L6 25/4/2017 Briquettes 3 L4L7 22/9/2016 Briquettes 10 L4L7 25/4/2017 Briquettes 15 L5L6 22/9/2016 Briquettes 1 L4L3 25/4/2017 Briquettes 38 L5L10 22/9/2016 Briquettes 16 L2L1 17/10/2016 Briquettes 70 L2L4 17/10/2016 Briquettes 3

80 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. – Adult Data. Discussion of Loxton Waikerie Results.

Adult mosquitoes.

A total of 4, 371 (n=53) adult mosquitoes were trapped within the Loxton Waikerie Council area during the 2016-17 season (Table 7.1). This was the fourth highest adult female mosquito catch since the commencement of this survey program (Table 7.5). This was also the lowest female mosquito total catch of the three upper River Murray local council areas for the 2016-17 season. The remaining councils all recorded their third highest mosquito populations in 18 years of surveillance. The high number of mosquitos caught in the 2016-17 season (4, 536 adjusted for n=55) follows on from the previous year which recorded the lowest total mosquito catch on record (338 adjusted for n=55) for Loxton Waikerie Council[7]. When adjusted for total trap nights (n=55) the total mosquitoes caught in the 2016-17 season, was around four times the median of 1, 075 and, almost twice the long-term average 2, 4411 (both corrected for n=55). The average monthly catch increase to just above the long-term average in September then increased dramatically in October before peaking in November. The mosquito population then halved, before declining further to below long-term trends in January and reading so for rest of the season. Overall, the peak in the mosquito population occurred in October through to November with trap totals of 1, 058, 1, 964 and 524 (n=5,4,5 respectively) then numbers declined and remained low for the remainder of the season. Interesting each trip over this period yielded more mosquitoes than all the mosquitoes caught in the previous season. This early season peak in mosquitoes was unlike previous years predominantly comprised of, Cx. australicus, An. annulipes (Chart 7.5), and to a lesser extent Cx. molestus, Cx. annulirostris (Chart 7.6).

Species worthy of consideration include:

Cx. australicus (1, 786, or 40.9% of the total catch) was the most numerous species caught within Loxton Waikerie Council and across the upper river. This is interesting as the species historically has only constituted around 3 % of all the mosquitoes caught within this council. Like the other two upper river councils, this species was most numerous in October and November, following the heavy rain in late September 2016 (Chart 7.6). Numbers then declined through December and only a few individuals were identified on traps set during 2017. Cx. australicus was not evenly distributed across the council with just over half (51%) of all individuals trapped at Kingston on the Murray (L4) and making up 69 % of all 81 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. mosquitoes from this site. Otherwise, this species was reasonably evenly distributed across the remaining sites with Loxton Golf Club (L1) recording the second highest number of Cx. australicus (220), and around half of all mosquitoes caught at this site. The Loxton Caravan Park site (L2) had the third highest catch (164) making up around 42 % of the catch at this site, the remaining sites recorded roughly the same number of mosquitoes with Moorook (L3) having 98, while Waikerie (L5) had 94 Cx. australicus. An. annulipes (1, 147, or 26.2% of the total catch) was the second most numerous species within the Loxton Waikerie Council. This is a dramatic increase on the 45 individuals caught in the previous season and an increase in the relative abundance of this species (up from 14.4 %). It is not surprising that this species was quite numerous this season as the unregulated flow event creates suitable conditions for this species. This species had a similar temporal distribution of the dominant species Cx. australicus peaking in abundance during November with 757 (n=4) individuals caught. Numbers then declined to just over 100 (n=5) during December and then was a significant part of the small catches over the remainder of the season (Chart 7.5). This species was fairly evenly represented across the council with the exception of Kingston on the Murray (L4) where it only comprised 6 % of the total catch for this location. At the other trap sites, this species represented between 15-30 % of the individuals caught at each location. An. annulipes was most numerous at Moorook (L3) where 34 % of all the individuals were caught, and it constituted 23 % of the total catch at this site. This species was also relatively abundant at the Loxton Golf Club (L1), with 26 % of all individual coming from this trap. An. annulipes made up nearly 30 % of all the individuals from this location. This is curious as this trap location is far from many of the water sources that typically harbour this species. This species was also well represented in the data from the Loxton Caravan Park (L2), where 19 % of the species catch was derived, this also represented ≈24 % of the total catch at this location. Cx. annulirostris (540, or 12.4 % of total catch) is a major vector of arbovirus and the third most common species within the Loxton Waikerie Council through the 2016-17 season. This species historically comprises around 34 % of the mosquito community within Loxton Waikerie Council. The abundance of this species is highly variable and influenced by environmental factors such as summer rainfall and temperature. During the current season the distribution of Cx. annulirostris spread across the season with increased numbers from November through January 2017 with a peak in abundance in December 2016 (Chart 7.5). This increased abundance occurred a month later than the more common species Cx. australicus and An. annulipes.

82 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. – Adult Data. The previous season over 70% of the adult female Cx. annulirostris was trapped at one location, Moorook, while over 2016-17 Cx. annulirostris was more widespread. As with the previous season Cx. annulirostris was found in the highest numbers at Moorook (L3) with 200 individuals or 38 % of all Cx. annulirostris caught. Cx. annulirostris was well represented in collections from Waikerie (L5) with 26.5 % of all individuals from this site belonging to this species. This was 111 individuals or 21 % of all Cx. annulirostris caught this season. Cx. annulirostris was also well represented at Loxton Caravan Park site (L2) where it represented 24 % of all individuals caught (92 individuals). This species was found in small numbers at the remaining trapping locations. Ae. camptorhynchus (375 or 8.6 % of the total catch) has historically, regularly constituted a major component of the mosquito fauna of the District Council of Loxton Waikerie. However, from 2010-11 to 2014-15 this species was practically absent from collections[10-12]. For example, during the 2013-14 season, only 27 individuals were trapped[10]. In subsequent years this changed with numbers increasing. During the 2016-17 season, Ae. camptorhynchus was found in the first half of the season with a peak occurring in November with 284 individuals being caught, subsequently, numbers dropped in December and were not found in in numbers through the new year. Across the council half of all Ae. camptorhynchus were caught at the Kingston on the Murray site (L1) where it was the second most abundant species. Ae. camptorhynchus was also caught in high numbers at Moorook (L3) 79 individuals representing 11 % of the total catch at this site (35% of the species catch). Ae. camptorhynchus was also caught in small numbers at the remaining trap sites. Cx. molestus (284, or 6.5 % of total catch) was the fifth most abundant species caught in the council areas this season the diversity in the mosquito community over 2016-17. This was an around twice the historic relative abundance of 3%. It also had a peak in abundance in October when it made up 23 % of the mosquito catch at this time. Ae. notoscriptus (41 or 1 % of the total catch), This species was only caught in very low numbers across the season, it was also caught at most trap locations within the council

83 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. - Discussion. Table 7.5. Summary of all monitoring seasons, Loxton Waikerie Council.

FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/2003 2003/2004 2004/2005 2005/2006

Rainfall Events Heavy, Oct. & Feb. Light, Sept, Dec. Oct. then dry A small pulse in March Generally Average Peaks in Aug/ Dec Wet winter average/ summer River Levels Peaks, Oct & Dec. Small peak Nov. Very small peak in March Elevated in September No major Elevations Total female Mosquitoes 6, 588 (n=45) 4, 748 (n=54) 701 (n=54) 379 (n=49) 2, 011 (n=51) 567 (n=53) 2, 736 (n=51) Mosquito Peak March December November Sept./ March September Oct/ Dec Nov/Dec Ae. camptorhynchus/ Dominant Species Cx. annulirostris Ae., Cx. & An. Ae. camptorhynchus. Ae camptorhynchus. Ae. camptorhynchus Ae. camptorhynchus Cx. quinquefasciatus Reported arbovirus infections ~40 (RRV) ~5 (RRV) ~6 (RRV) None confirmed ~1 (RRV) ~2 (RRV) ~6 (RRV)

FEATURE 2006/2007 2007/2008 2008/2009 2009/2010 2010/2011 2011/2012

Late season Jan., Average winter, Peak in Aug, Average peaks in Sept/ Above Average Oct-Jan, & Rainfall Events November December/September March/April Nov/Dec Nov/March March 50 cm drop in lock 4 D/S Raised downstream in Raised around Lock 4 Aug/ High water until October, River Levels No major Elevations No extraordinary peaks pool in Jan. Summer Feb & March Nov, peak in Feb January pulse, April flood Total female Mosquitoes 1, 287 (n=52) 401 (n=53) 1 ,069 (n=52) 964 (n=52) 9, 536 (n=49) 727 (n=48) Mosquito Peak September November September / November October/ March Jan/ October April Ae. camptorhynchus/ Cx. globocoxitus/ Ae. camptorhynchus/ Dominant Species Ae. camptorhynchus Ae. camptorhynchus Cx. annulirostris Cq. linealis An annulipes Cx. annulirostris Reported arbovirus infections ~10 (RRV) 5 (RRV), 3 (BFV) 3 (RRV), 2 (BFV) 12 (RRV) 129 (RRV), 18 (BFV) 18 (RRV), 6 (BFV)

FEATURE 2012/2013 20013/ 14 20014/ 15 20015/ 16 2016/2017

Rainfall Events Below average Feb rain event Jan rain event November and Jan rain event September Variable downstream of locks late Raised downstream of locks in Raised downstream of Lock 4 over River Levels raised downstream of Lock Unregulated flow late 2016 2012 spring season Total female Mosquitoes 806 (n=50) 388 (n=53) 1, 917 (n=52) 313 (n=51) 4, 371 (n=53) Mosquito Peak October/ January August/September No real peaks November An annulipes /Cx. annulirostris/ Cx. molestus/ Cx. quinquefasciatus/ Dominant Species Ae. camptorhynchus Ae. camptorhynchus Cx. australicus/ An annulipes Cx. molestus Ae. notoscriptus Reported arbovirus infections 16 (RRV), 8 (BFV) 5(RRV), 3 (BFV) 1 (RRV) 1 (RRV) 49 (RRV, 43 probables, 6 confirmed)

84 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie.

COMMENTS.

This season recorded a dramatic increase in mosquito numbers from the previous season from 313 (n=51) in 2015-16, to 4, 371 (n=53). This was the fourth highest adult female catch records from the Loxton Waikerie Council over the 18 years the program has been running. The cool weather Culex mosquito Cx. australicus was the most abundant mosquito species to be recorded in the Loxton Waikerie Council during the 2016/17 season. Cx. australicus was found in increased abundance over October and November, due to above average rainfall in late September (Chart 7.5). Numbers then declined into the new year, this pattern was shared by other common species with peaks in abundance either coinciding or occurring slightly later in the season (Chart 7.6). There were no large mosquito catches in the council from January 2017. Over the 2016-17 season conditions across the council were influenced by higher than average rain in spring and the unregulated flow event that resulted in the inundation of the floodplain along the river. The effect on the mosquito community was interesting with increased numbers of An. annulipes and Cx. annulirostris. This is to be expected as both species favour these conditions, however, it is surprising that the peak in abundance of Cx. annulirostris was subdued in this council as well as Renmark Paringa Council while being more pronounced in the Berri Barmera Council. The distribution of mosquitos across the 2016-17 season was characterised by populations many times the historic averages from October through to December and subdued numbers across the remainder of the season (Chart 7.7). As previously stated the most common species in these early season catches were Cx. australicus and An. annulipes this is unusual as historically the most common species is Ae. camptorhynchus, this was due to conditions favouring these species. Although Ae. camptorhynchus was caught in the council numbers were not high in terms of by historic data. The species was also not found in high numbers associated with traps located in the major towns. This is positive as Ae. camptorhynchus can be an aggressive biter and is thought to be associated with the disease. The pest species Cx. molestus was again a major component of the mosquito community at Waikerie, indicating a problem site that requires further monitoring. Last season a drain near the trap site underwent some modification to improve drainage ongoing monitoring in more typical years will better inform the effect on mosquito numbers at this site. Monitoring of larvae sites was most intensive following the large rain event of September 2016 and the unregulated flow event of the latter part of the year. Large rain events such as this present a high risk if increases in the populations of the major vector species Cx. annulirostris. This

85 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie. was a concern as adult female Cx. annulirostris are able to reproduce quickly and this species has the potential to both inflict nuisance biting and act as a vector of arbovirus. There was an only moderate increase in Cx. annulirostris numbers following the higher than average rain from December through to February rain which followed the unregulated flow of the river. Overall larvae treatment was focused on Spring and Autumn preventative treatment of known problem sites. In the District Council of Loxton Waikerie, there were 49 notifications of RRV reported across the council 43 probable and 6 confirmed. As with the other upper river Council and consistent with the state as a whole there was a peak in the estimated time of onset from December extending through to February 2017, all with an estimated date of onset mid-March 2016.

86 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 7. Results: The District Council of Loxton Waikerie.

LOCAL RECOMMENDATIONS.

The re-emergence of Ae. camptorhynchus as a major component of the mosquito fauna in the upper river councils is an important issue. Unlike many of the other mosquitoes in this region Ae. camptorhynchus is a cool weather mosquito and usually has a peak in abundance in the early months of the program when it is an aggressive outdoor biter. In previous years this species has been a pest within the council especially during spring. It is presumed that the egg bank of this species was depleted due to the flooding event of early 2011. It is proposed that known larvae sites of this species be monitored and targeted for a winter control programs when appropriate to reduce the impact of the spring flushes of mosquitoes. The new Passive trap system should be considered while it has great potential the inclusion of FTA cards in EVS traps may be more effective as a surveillance tool in periods of high mosquito activity. Technical issues continue to hamper deployment along with site selection. More local involvement should be considered in future deployments, and potentially the technology would be more useful in locations not serviced by EVS traps. Establish permanent S-Methoprene stations at known problem larva sites within the council, particularly for sites that are active annually. It is important to strive for the environmental health effects of environmental flows and wetland inundation is considered by water managers when planning. The mosquito communities’ response needs to be a consideration when undertaking these activities. Consulted of EHO’s and factored in the monitoring of the mosquito populations (both larva and adult) when conducting these activities is the ideal. Communication channels are having been developed but this is an ongoing issue and requires continual improvement; this will take some time to resolve as new water management practices evolve and health issues require consideration.

87 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

8. RESULTS FOR THE MID-MURRAY COUNCIL. Adult trap site descriptions.

MM1 Morgan Ferry Longitude: E139 40.630 Latitude: S34 02.341

MM2 Blanchetown Longitude: E139 36.965 Latitude: S34 21.457

88 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

MM3 Swan Reach

Longitude: E139 35.860 Latitude: S34 33.764

MM4 Mannum Caravan Park

Longitude: E139 19.044 Latitude: S34 54.569

89 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: The Mid-Murray Council.

MM5 Port Mannum Sewage Works

Longitude: E139 18.165 Latitude: S34 55.801

90 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

Weather Data: Mid-Murray Council.

Total monthly rainfall data are shown for four Bureau of Meteorology Weather Stations: Morgan (Brenda Park Station [station 24578]) Chart 8.1, Blanchetown (station 24564) Chart 8.2, Swan Reach (station 24535) Chart 8.3, and Mannum (station 24517) Chart 8.4. Overall, the total annual precipitation to May 2017 at Morgan (388.1 mm), Blanchetown (404.4 mm) and Swan Reach (376.2 mm) and Mannum (405.6 mm) were higher than their historic means (282.5 mm, 298.1, 274.1 mm, and 296.7 mm [253.3.4 mm corrected for missing data]) by 105.6 mm, 106.3 mm, 102.1 mm and 149.3 mm (over 10 months) respectively. Data from Mannum Council Depot station was incomplete with at least 16 % of data missing. From the data remaining it appears the heaviest falls were recorded in September with 107.7 mm of precipitation, this in around three times the long-term trend (36.9 mm). This pattern of higher than long-term precipitation during September was observed at the three other weather stations in the council although to a lesser extent. Over the remainder of the season (where data is available) precipitation was variable with summer months and April generally recording higher precipitation than long-term trends at most weather stations. Otherwise, the remainder of spring was slightly drier than long term trends, while March 2017 recorded hardly any precipitation. All four weather stations had broadly similar patterns of precipitation, with similar peaks and troughs throughout the season. The month with the highest precipitation differed between stations with Morgan recording the highest precipitation during December (59.9 mm, Chart 8.1) while Blanchetown (72.2 mm, Chart 8.2), Mannum (79.1 mm, Chart 8.4) and Swan Reach (68.9 mm, Chart 8.3) all recorded their highest rainfall during September. As no temperature data is available from the weather stations within the council this must be inferred from other councils, such as Loxton and Renmark to the north or Murray Bridge to the south.

91 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. - Weather Data.

Chart 8.1. Total Monthly Precipitation (mm) at Morgan (Brenda Park Station) Weather Station (24578) during the 2016-17 Trapping Period Compared with the Historic Mean. 80.00 Total precipitation Historic Mean

70.00

60.00

50.00

40.00

30.00 Precipitation (mm) Precipitation 20.00

10.00

0.00 May June July August September October November December January February March April

Month Chart 8.2. Total Monthly Precipitation (mm) at Blanchetown Weather Station (24564) during the 2016-17 Trapping Period Compared with the Historic Mean.

80.00 Total precipitation Historic Mean

70.00

60.00

50.00

40.00

30.00 Precipitation (mm) Precipitation

20.00

10.00

0.00 May June July August September October November December January February March April Month

92 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. - Weather Data.

Chart 8.3. Total Monthly Precipitation (mm) at Swan Reach Weather Station (24535) during the 2016-17 Trapping Period Compared with the Historic Mean. 80.00 Total precipitation Historic Mean

70.00

60.00

50.00

40.00

30.00

Precipitation (mm) Precipitation 20.00

10.00

0.00

Month Chart 8.4. Total Monthly Precipitation (mm) at Mannum Weather Station (24517) during the 2016-17 Trapping Period Compared with the Historic Mean. 80.00

70.00

60.00

50.00

40.00

30.00 Precipitation (mm) Precipitation 20.00

10.00

0.00 May June July August September October November December January February March April

Month NOTE: Figures above run from May 2016, four months before the start of this sampling season.

93 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. -Adult Data

Adult mosquito trapping results: Mid-Murray Council. Chart 8.5. Mid-Murray Council, total, and Ae. camptorhynchus adult female mosquitoes over the 2016-17 season.

Chart 8.6. Mid-Murray Council, total and secondary species of adult mosquitoes caught in the 2016-17 season.

94 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

Chart 8.7. Mid-Murray Council, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

95 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. -Adult Data

Table 8.1. Totals for the five traps in Mid-Murray Council Area. Species 29/08/16 20/09/16 16/10/16 9/11/16 3/12/16 20/12/16 13/01/17 9/02/17 4/03/17 28/03/17 24/04/17 Season Total Ae. alboannulatus 3 0 0 0 0 0 0 0 0 0 1 4 Ae. camptorhynchus 63 135 166 1428.7 555 335 4934 197 155 31 5 8004.7 Ae. notoscriptus 23 7 0 0 0 5 1 2 10 1 16 65 Ae. sagax 31 1 1 0 0 0 0 0 0 0 0 33 An. annulipes 46 7 152 0 368 154 29 11 4 4 1 776 Cq. linealis 0 0 0 0 0 2 12.5 0 0 0 0 14.5 Cx. annulirostris 16 1 101 0 70 45 364 198 23 2 1 821 Cx. australicus 2 100 103 0 5 18 0 0 0 0 1 229 Cx. cylindricus 1 0 0 0 0 0 0 0 0 0 0 1 Cx. globocoxitus 0 2 23 26 3 3 2 0 1 3 0 63 Cx. molestus 29 5 6 0 1 3 3 2 1 1 0 51 Cx. quinquefasciatus 2 0 1 0 8 4 21.5 4 3 0 0 43.5 Tp. atripes 0 0 0 0 0 0 0 1 0 3 0 4 Unidentifiable 0 0 3 0 0 1 0 0 0 0 2 6 Male 0 0 0 17 51 1 0 1 0 0 0 70 Total Adults 216 258 556 1454.7 1010 570 5367 415 197 45 27 10115.7 n=5 n=5 n=4 n=5 n=5 n=5 n=5 n=5 n=5 n=5 n=4 Total (n=53)

96 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

Table 8.2. Average Catch for the five traps in Mid-Murray Council Area.

Species 29/08/16 20/09/16 16/10/16 9/11/16 3/12/16 20/12/16 13/01/17 9/02/17 4/03/17 28/03/17 24/04/17 Ae. alboannulatus 0.6 0 0 0 0 0 0 0 0 0 0.25 SE 1.342 0 0 0 0 0 0 0 0 0 0.5 Ae. calabyi 12.6 27 41.5 285.74 111 67 986.8 39.4 31 6.2 1.25 SE 26.51 59.816 56.889 636.698 239.344 145.356 2178.154 85.882 69.318 12.775 2.5 Ae. camptorhynchus 12.6 27 41.5 285.74 111 67 986.8 39.4 31 6.2 1.25 SE 26.51 59.816 56.889 636.698 239.344 145.356 2178.154 85.882 69.318 12.775 2.5 Ae. clelandi 4.6 1.4 0 0 0 1 0.2 0.4 2 0.2 4 SE 5.079 3.13 0 0 0 2.236 0.447 0.548 3.937 0.447 7.348 Ae. notoscriptus 4.6 1.4 0 0 0 1 0.2 0.4 2 0.2 4 SE 5.079 3.13 0 0 0 2.236 0.447 0.548 3.937 0.447 7.348 Ae. sagax 6.2 0.2 0.25 0 0 0 0 0 0 0 0 SE 13.864 0.447 0.5 0 0 0 0 0 0 0 0 An. annulipes 9.2 1.4 38 0 73.6 30.8 5.8 2.2 0.8 0.8 0.25 SE 20.572 1.673 70.09 0 156.244 41.794 10.756 3.194 1.304 1.304 0.5 Cq. linealis 0 0 0 0 0 0.4 2.5 0 0 0 0 SE 0 0 0 0 0 0.894 5.59 0 0 0 0 Cx. annulirostris 3.2 0.2 25.25 0 14 9 72.8 39.6 4.6 0.4 0.25 SE 6.611 0.447 45.272 0 19.987 8.544 97.661 74.849 3.362 0.894 0.5 Cx. australicus 0.4 20 25.75 0 1 3.6 0 0 0 0 0.25 SE 0.548 25.209 39.025 0 1.414 2.51 0 0 0 0 0.5 Cx. cylindricus 0.2 0 0 0 0 0 0 0 0 0 0 SE 0.447 0 0 0 0 0 0 0 0 0 0 Cx. globocoxitus 0 0.4 5.75 5.2 0.6 0.6 0.4 0 0.2 0.6 0 SE 0 0.548 4.5 11.628 0.894 1.342 0.894 0 0.447 0.894 0 Cx. molestus 5.8 1 1.5 0 0.2 0.6 0.6 0.4 0.2 0.2 0 SE 12.969 1.732 3 0 0.447 0.894 0.894 0.548 0.447 0.447 0 Cx. quinquefasciatus 0.4 0 0.25 0 1.6 0.8 4.3 0.8 0.6 0 0 SE 0.894 0 0.5 0 2.608 1.789 4.919 1.304 0.894 0 0 Tp. atripes 0 0 0 0 0 0 0 0.2 0 0.6 0 SE 0 0 0 0 0 0 0 0.447 0 1.342 0 Unidentifiable 0 0 0.75 0 0 0.2 0 0 0 0 0.5 SE 0 0 0.957 0 0 0.447 0 0 0 0 0.577 Male 0 0 0 3.4 10.2 0.2 0 0.2 0 0 0 SE 0 0 0 7.603 22.253 0.447 0 0.447 0 0 0 no captures 0 1 0 0 0 0 0 0 1 1 1 Trap failures 0 0 1 0 0 0 0 0 0 0 1 Total Adults 43.2 51.6 139 290.94 202 114 1073.4 83 39.4 9 6.75 SE 33.147 56.946 85.685 648.326 388.222 168.862 2158.992 98.577 75.949 13.191 10.905 n=5 n=5 n=4 n=5 n=5 n=5 n=5 n=5 n=5 n=5 n=4

97 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. Mosquito Larval Dipping and Treatment: Mid-Murray Council. Table 8.3. Results of Larval Dipping within Mid-Murray Council.

Site Trip Date Site Condition Larvae present Ae. camptorhynchus Density MM4L5 1 27/8/2016 Full Yes * Medium MM2L3 2 21/9/2016 Full No MM3L15 2 21/9/2016 Full * Low MM4L5 2 22/9/2016 Full Yes * Medium MM1L8 6 20/12/2016 Full No MM1L10 6 20/12/2016 Full No MM1L8 7 13/1/2017 Full No MM1L10 7 13/1/2017 Full No

Mid-Murray Larvicide Treatments.

The high river over the 2010/11 season, affected the mosquito community in the upper part of the River Murray including the area monitored north of Mannum in the Mid Murray Council. The effects of this event seem to have dissipated in the upper river local council areas monitored there has been a return to pre-flood conditions with small numbers of Ae. camptorhynchus identified from trap retrieved from adult trap sites north of Mannum within Mid- Murray Council. Larva sites around Mid-Murray Council were monitored throughout the season and treatments applied as required. The locations selected for treatment were typical of the potential vector species Ae. camptorhynchus and Cx. annulirostris. The problem site located near Mannum MM5L4 was of particular concern as it located on the opposite side of the river from Mannum (Table 8.4) this site was treated early in the season to alleviate any issues that it could cause. In addition to the monitoring and control efforts by the Mosquito a Public Health Research Group with the continuation of the informal relationship with SA Water. Harry Roberts from SA Water has been conducting active monitoring and treatment of larvae sites around the Mannum Sewage works (Table 8.5). SA Water has received monitoring data and arboviral screening data to assist them in understanding the mosquito community around the Mannum Sewage works.

98 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. Table 8.4. Larvicide application in Mid Murray Council during the 2016-17 season.

Site Date Product Quantity MM4L5 27/8/2016 Briquettes 23 MM3L15 21/9/2016 Briquettes 4 MM4L2 22/9/2016 Briquettes 16 MM4L5 22/9/2016 Briquettes 27

Table 8.5. Additional treatment by Harry Roberts SA Water (Pt Mannum Sewage Works).

ustralicus

Dry

annulirostris

camptorhynchus

Treatment

NoLarvae

An. annulipes An.

young Aedes sp young Aedes

Cx. Cx.

Date Site Ae. 21/08/2016 North Swale * * Pellets South Drain * * Briquettes 20/09/2016 North Swale * Pellets South Drain * 15/10/2016 North Swale * Pellets South Drain * Briquettes 21/11/2016 North Swale * Pellets South Drain * * 11/12/2016 North Swale * Pellets South Drain * 18/01/2017 North Swale * Pellets South Drain * Briquettes 15/02/2017 North Swale * South Drain * Briquettes 15/03/2017 North Swale * South Drain * Briquettes 19/04/2017 North Swale * South Drain * "DRY" means dry or insufficient water to obtain a sample

99 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

Discussion of Mid-Murray Results.

Adult mosquitoes. A total of 10, 115.7 (n=53) adult mosquitoes were trapped within the Mid-Murray Council area during the current season, this was the highest mosquito catch in the 18 years of the River surveillance program. This was over six times the total number of mosquitoes trapped in the previous season (1, 561, n=49) and around 7 % higher than the next largest catch of 9,787 (corrected for n=55) which was obtained in the flood season of 2010-11. That was a very different season with the community then dominated by the floodwater species Cx. annulirostris, this season it only comprised just over 8 % of the mosquito community. During the 2016-17 season, ≈79% of all mosquitoes caught were Ae. camptorhynchus, this species is often a major component of the mosquito community particularly around the Pt Mannum trap site where the majority of specimens were obtained this season. The seasonal distribution of mosquitoes within Mid Murray council differed from the three upper river councils (Chart 8.5, Chart 7.5, Chat 6.3 and Chart 5.4). The distribution of Ae. camptorhynchus across the season was unusual with an above average peak in abundance in November which would be expected, this was however followed by a much larger catch of this species in January following the drop in the river (Table 8.7). Unlike the three upper river councils Cx. australicus only made up a small component of the mosquito community contributing. The total number of adult female mosquitoes caught in the 2015-16 season 10, 497 adjusted for n=55, was above the adjusted long-term average of 2, 276 mosquitoes, although slightly greater than the median of 1, 464, this is a departure from the two previous seasons which represent “typical conditions” with respect to overall mosquito numbers (Chart 8.6).

Species worthy of consideration include:

Ae. camptorhynchus (8004.7, or 79.1% of total catch) overall this species was the most abundant mosquito within the council catch. Although true this statement is misleading with 7, 875 of the 8, 005 individuals or 98.4 % of the total species catch originating at the Port Mannum site (MM5). Of the remaining individual’s eighty-five percent (110 individuals) came from the Mannum Caravan Park adult trap sites, with the remaining individuals dispersed amongst the remaining trap locations. As with previous years Ae. camptorhynchus had a strong peak in abundance early in the season, far exceeding the historic mean in November, this was then surpassed in January with a record mosquito catch for the Council (Chart 8.7). Despite the above

100 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. - Discussion. average rainfall towards the end of the season, there was no increase in Ae. camptorhynchus numbers in during March or April 2016. Over the years several larvae sites have been identified on nearby SA water land and treated as required. SA Water has been made aware of potential issues of mosquito larvae sites occurring on land they manage and have been very cooperative in addressing this issue. Cx. annulirostris (821, or 8.1% of total catch) This species was overall the second most abundant member of the mosquito fauna of the council this season (Table 8.1) and had an eight- fold increase on the previous season (104, or 6.6% of total catch). This species is considered to be an important potential arbovirus vector and therefore worth considering. Cx. annulirostris had two periods of elevated abundance over the 2016-17 season, the first occurring in October 2016 where 101 individuals were caught, the majority (93) coming from Morgan Ferry (MM1). This was followed by a second peak in abundance which occurs in January 2017, as with the earlier peak the majority of individuals came from Morgan Ferry while a sizable cohort came from Swan Reach Ferry (MM3). Overall ≈68% of all Cx. annulirostris caught originated from traps set at Morgan Ferry (MM1) with the Swan Reach Ferry (MM3) trap site contributing around a quarter of all Cx. annulirostris caught this season. An. annulipes (776, or 7.7 % of total catch) this species was the third most common species overall a change from the previous season when it was the fifth most abundant species. Like Cx. annulirostris, An. annulipes had a bimodal distribution with the second peak occurring earlier in December than Cx. annulirostris. As with the previous season An. annulipes was caught in highest abundance at the Port Mannum site with 448 individuals caught at this site representing 5.3% of the total catch at this site and around 58% of all the An. annulipes trapped within the council. An. annulipes numbers were highest in December 2016 with 368 individuals trapped this was almost half of all the An. annulipes individuals caught this season (Chart 8.6). Cx. australicus, (229, or 2.3 % of total catch) was only a minor component of the mosquito fauna within the council, and only the fourth most abundant species (Chart 8.6). This species is generally not considered to be a nuisance bitter of humans and of limited disease risk in Australia. Cx. australicus was not evenly distributed across the council with over half of all Cx. australicus individuals (54 %) were caught at the Swan Reach Ferry while a further 27 % of all Cx. australicus were caught at the Blanchetown golf course. This species was also found in a small number at the remaining sites within the council.

101 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. - Discussion.

Ae. notoscriptus (65 or 0.6 % of the total catch), although only caught in small numbers this species was the fifth most abundant species caught in the Mid-Murray Council. Ae. notoscriptus was caught throughout the season (Table 8.1), and as with the previous season was recorded predominantly at the Port Mannum site with 74 % of all individuals trapped at this site. This species is known as a “container breeder” and causes nuisance biting even in low numbers. Ae. notoscriptus do not disperse far and are generally trap shy therefore modest catches usually indicates a problem site nearby.

102 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. - Discussion. Table 8.6. Summary of all monitoring seasons, Mid-Murray Council.

FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/ 2003 2003/ 2004 2004/ 2005 2005/ 2006 2006/ 2007

Rainfall Events Light, Sept. Jan. Light, Sept, Dec. Oct Feb/ March Aug Dec Average January, March/April River Levels No data Peaks, Oct and Dec. Small peak Nov. raised in Feb./ March Slightly elevated No peak Small Total female Mosquitoes 1, 763 (n=44) 1,873 (n=54) 594 (n=54) 442 (n=52) 1, 270 (n=55) 1, 387 (n=54) 2, 188 (n=52) 475 (n=51) Mosquito Peak October Sept. & Nov. Oct. & April March Feb Sept & Jan October Sept. Feb. & April Ae. camptorhynchus/ Dominant Species Ae. camptorhynchus. Three: Ae., Cx. & An. Ae. camptorhynchus. Ae. camptorhynchus. Cx. annulirostris Ae. camptorhynchus Ae. camptorhynchus Cx. molestus Reported arbovirus infections ~11 (RRV) ~26 (RRV) ~3 (RRV) None confirmed ~2 (RRV) ~2 (RRV) ~8 (RRV) 1 (RRV)

FEATURE 2007/ 2008 2008/ 2009 2009/ 2010 2010/ 2011 2011/ 2012 2012/ 2013

Rainfall Events November Aug, Nov/Dec Sept/Nov/ March Dec, Feb & March Dec & March Dec., March Raised downstream in Around Lock 4 raised from Variable, High until October, Variable downstream of locks in River Levels River Level unvaried No extraordinary peaks Summer Feb & March Aug/ Nov, Feb pea. January pulse, April flood. 2012 Total female Mosquitoes 334 (n=54) 490 (n=52) 1, 120 (n=51) 9, 431 (n=53) 1, 329 (n=49) 1, 333 (n=50) Mosquito Peak November November October/ April October/ January April Late September, February Dominant Species An. annulipes/ Cx. annulirostris Cx. molestus Ae. camptorhynchus Cx. annulirostris Cx. annulirostris Ae. camptorhynchus/ Cx. molestus Reported arbovirus infections 2 (RRV), 2 (BFV) 2 (RRV),1 (BFV) 9 (RRV), 1 (BFV) 153 (RRV), 7 (BFV), 1 (MVE) 6 (RRV), 4 (BFV) 5 (RRV)

FEATURE 2013/2014 2014/2015 2015/2016 2016/2017

Rainfall Events Wet winter/ February Jan rain event March, September & December River Levels Variable downstream of locks in 2013 spring locks raised Downstream Flat above Lock 1 variable below Unregulated flow late 2016 Total female Mosquitoes 1, 556 (n=49) 1, 408 (n=53) 1, 561 (n=49) 10, 116 (n=53) Mosquito Peak September/ December/ March October/ February September/ October January Dominant Species Ae. camptorhynchus/ Cx. molestus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Reported arbovirus infections 2 (RRV), 2 3 (RRV) 4 (RRV) 37 (RRV, 26 probables, 11 confirmed)

103 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. – Comments

COMMENTS.

This season recorded the highest mosquito numbers since the commencement of this monitoring program (Table 8.6) with 10, 115.7 (n=53) mosquitoes caught across the Mid-Murray Council during the 2016-17 season. This was over four times the historic season mean of 2, 193 mosquitoes (adjusted for n=53). During the 2014-15 season numbers of the cool weather mosquito Ae. camptorhynchus rebounded in the upper River Murray Councils and was only recorded in low numbers in traps located north of Mannum in the Mid Murray Council. This continued in 2016-17, although due to season effects the numbers of this species in the upper river councils, however, other species were far more numerous. As with previous seasons, the mosquito community around Mannum was characterised by an early season peak in trap numbers particularly around Port Mannum. However, there was a second period of increased abundance in January 2017, which was much higher than November. The difference between the numbers of Ae. camptorhynchus caught around Mannum and the remainder of the council is also consistent with previous years. This season 84% of all mosquitoes trapped within the council were caught at the Port Mannum location and of this ≈93 % were the Aedes species Ae. camptorhynchus (98.4% of all individuals of this species). Due to the concentration of this species around the town of Mannum control efforts were focussed on known Ae. camptorhynchus larvae sites in the surrounding area. The main location controlled was MM5L4 located on the southern bank of the River Murray adjacent the Mannum Caravan Park. This season co- operation with SA Water continued with monitoring and treatment of known larvae sites on SA Water land around the Port Mannum undertaken by their scientific staff, Harry Roberts. Throughout the season feedback on control efforts by SA Water was provided by The Healthy Environments, Healthy People Research Unit. Mosquito Trap data was also supplied to the SA Water to assist in control efforts. The second most common species of mosquito within the Mid-Murray Council was the arboviral vector Cx. annulirostris, this species was most common at both Port Mannum and Morgan Ferry. In the Mid Murray Council, there were 37 notifications of RRV reported, 26 probables and 11 confirmed cases. There was an increase in notifications with a date of onset from December with a peak in February a little later than the three upper river councils. These cases seemed to be associated with both higher abundances of both Ae. camptorhynchus and Cx. annulirostris recorded in January.

104 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council.

This season a further trial of the passive mosquito trap utilising a new method for screening mosquitoes for arboviruses along the River Murray. Within Mid Murray Council area, no passive trap was deployed in the Mid-Murray Council. Passive traps were deployed adjacent the Department of Health’s Sentinel Chicken Flocks, none of which have been sighted in the Mid-Murray Council. The Healthy Environments, Healthy People Research Group placed FTA cards into 40 % of the regular EVS traps as part of the regular trapping program. In December, an FTA card set in an EVS trap located at Wellington Caravan Park. In response, there was an increase in the percentage of EVS traps holding FTA cards. In the new year, there was a detection of Sindbis virus on an FTA card from an EVS trap set at Morgan Ferry (MM1) during February 2017. The significance of the information gained from this trial and the usefulness of these methods are being considered and more widespread trials in future years may result.

105 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 8. Results: Mid-Murray Council. – Comments

LOCAL RECOMMENDATIONS.

Establish permanent S-Methoprene stations at MM5L4 with co-operation from the landholder and other known problem larva sites within the council, particularly for sites that are active annually. The trial of the new Passive trap system should be continued and the response and implications of arboviral detections are established. The possibility of different locations should be considered. Continue the cooperation and communication with SA Water with regard to the management of mosquito populations on Mannum Sewerage Works land. It is important to strive for the environmental health effects of environmental flows and wetland inundation is considered by water managers when planning. The mosquito communities’ response needs to be a consideration when undertaking these activities. Consulted of EHO’s and factored in the monitoring of the mosquito populations (both larva and adult) when conducting these activities is the ideal. Communication channels are had been developed but this is an ongoing issue and requires continual improvement; this will take some time to resolve as new water management practices evolve and health issues require consideration.

106 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

9. RESULTS FOR THE RURAL CITY OF MURRAY BRIDGE. Adult trap site descriptions.

MB1. Mypolonga School Longitude: E139 21.476 Latitude: S35 02.515

MB2. Sturt Reserve Longitude: E139 17.271 Latitude: S35 07.427

107 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge

MB3. Murray Bridge Golf Course

Longitude: E139 16.199 Latitude: S35 07.837

MB4. Jervois Bowling Club Longitude: E139 26.318 Latitude: S35 15.951

108 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge

MB5. Wellington Caravan Park

Longitude: E139 22.927 Latitude: S35 19.808

109 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge

Weather Data: The Rural City of Murray Bridge. Weather data from Weather Station at Murray Bridge (Station number 24521) were supplied by the Bureau of Meteorology. The 2016-2017 season had generally warmer daily maximum and minimum temperatures than long term trends with the exception of spring 2016 which was on the average cooler. During winter of 2016 daily maximum and minimum temperatures exceeded the long-term means by 0.53 ºC and 0.23 ºC, resulting in both warmer than expected winter days and nights. The spring that followed was cooler than “normal” conditions with seasonal average daily maximum and minimum temperatures falling short of long term trends. The month of September had particularly cool days with the average daily maximum temperature 1.5 ºC less than the long-term average for the month. Days gradually became warmer relative to long-term trends, with the discrepancy between the actual and historic monthly average narrowing. By summer the situation had reversed with the average exceeding the historic daily maximum temperatures by 1.7 ºC this increased in January to 1.9 ºC. In February daytime temperatures approximated long term averages but failed to decline in with the long-term mean at this level resulting in comparatively warmer March and April days during 2017 (Chart 9.2). The Daily Minimum Temperatures that is the nights gradually became comparatively cooler through spring with the difference between actual and historic means increasing from -0.5 ºC in September to -0.9 ºC, by November. There was a change in conditions in January with the average daily minimum temperature exceeding the long- term mean by 1.2 ºC, and 1.8 ºC in March 2017 with a relatively “Normal” intervening month. The 14DMADMax first rose above 25 ºC in early November 2016 well over a month later than the previous season. This only occurred for a day before the 14DMADMax dropped back again below this level for four days then increased above 25 ºC and remained above this level for the majority of the remainder of the season, with the exception of a few days at the end and beginning of the season. During this period, the 14DMADMax also rose above 30 ºC from the middle of December through to end of January then dropped below 30 ºC for most of February before increasing again to remain above 30 ºC for most of the month of March (Chart 9.1). The 14DMADMin rose above 15 ºC on six occasions broadly corresponding to periods when the 14DMADMax also rose above 30 ºC.

110 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. - Weather Data.

The annual precipitation to May 2017 was 485.4 mm, exceeding the long-term mean at Murray Bridge Weather Station (350.2 mm) by 89.2 ºC. Precipitation during all seasons was around trend, with the exception of July-September and December which all recorded precipitation in excess of historic means (Chart 9.3).

111 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. - Weather Data

Chart 9.1. Murray Bridge Weather Station (24521) Maximum and Minimum Temperature, 14-day Moving Average from May 2016 to April 2017.

C ° 25

Temperature 15

Date

Chart 9.2. Murray Bridge Weather Station (24521) Monthly Mean Maximum and Minimum Temperature May 2016 to April 2017 compared to historic means (solid line).

120.00 Total precipitation Historic Mean

100.00

80.00

60.00

Precipitation (mm) Precipitation 40.00

20.00

0.00 May June July August September October November December January February March April Month

112 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. - Weather Data.

Chart 9.3. Total Monthly Precipitation (mm) at Murray Bridge Weather Station (24521) during the 2016- 17 Trapping Period Compared with the Historic Mean. 40 Mean max temp 2016-17 Historic mean Mean min temp 2016-17 Historic min

25 C ° 20

15 Temperature Temperature

0 May June July August September October November December January February March April Month

NOTE: Figures above run from May 2016, four months before the start of this sampling season. .

113 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge.

Adult mosquito trapping results: The Rural City of Murray Bridge. Chart 9.4. Rural City of Murray Bridge Council, total adult, and Ae. camptorhynchus female mosquitoes caught in the 2016-17 season.

Chart 9.5. Rural City of Murray Bridge Council, total and secondary species of adult mosquitoes caught in the 2016-17 season.

114 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. -Adult Data.

Chart 9.6. Rural City of Murray Bridge Council Area, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

115 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. - Adult Data

Table 9.1. Totals for the five traps in Rural City of Murray Bridge Council Area. Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 20/12/16 12/01/17 7/02/17 2/03/17 27/03/17 23/04/17 Season Total Ae. alboannulatus 0 0 0 1 0 0 0 1 1 14 3 20 Ae. camptorhynchus 144 599 2653 1907.3 558 126 1614 159 25 40 20 7845.3 Ae. notoscriptus 0 5 1 11 4 0 6 6 8 32 6 79 An. annulipes 0 0 0 131.3 31 12 23 3 1 11 0 212.3 Cq. linealis 0 0 0 10 16 68 28 14 65 30 1 232 Cx. annulirostris 0 0 0 6 9 5 29 59 5 34 0 147 Cx. australicus 0 0 2 23.1 44 1 0 0 0 0 0 70.1 Cx. globocoxitus 0 4 2 42 58 37 84 76 3 7 23 336 Cx. molestus 0 3 0 4 12 3 5 0 8 129 6 170 Cx. quinquefasciatus 0 4 1 1 2 40 1 0 2 2 0 53 Ma. uniformis 0 0 0 0 0 0 1 0 0 0 1 2 Tp. atripes 0 0 0 0 0 0 0 4 0 0 0 4 Unidentifiable 0 1 0 52.1 0 1 1 0 0 4 0 59.1 Male 1 1 0 3 17 4 11 1 5 5 0 48 Total Adults 144 616 2659 2188.8 734 293 1792 322 118 303 60 9229.8 n=5 n=5 n=5 n=5 n=5 n=4 n=5 n=5 n=4 n=5 n=5 Total (n=53)

116 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. -Adult Data.

Table 9.2. Average Catch for the five traps in Rural City of Murray Bridge Council Area.

Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 20/12/16 12/01/17 7/02/17 2/03/17 27/03/17 23/04/17 Ae. alboannulatus 0 0 0 0.2 0 0 0 0.2 0.25 2.8 0.6 SE 0 0 0 0.2 0 0 0 0.2 0.25 1.497 0.4 Ae. camptorhynchus 28.8 119.8 530.6 381.46 111.6 31.5 322.8 31.8 6.25 8 4 SE 22.659 75.778 451.119 323.056 79.489 21.223 101.89 27.361 2.898 4.087 1.732 Ae. notoscriptus 0 1 0.2 2.2 0.8 0 1.2 1.2 2 6.4 1.2 SE 0 0.775 0.2 1.96 0.49 0 0.8 0.583 1.08 2.909 0.49 An. annulipes 0 0 0 26.26 6.2 3 4.6 0.6 0.25 2.2 0 SE 0 0 0 26.011 4.727 1.78 1.4 0.6 0.25 1.2 0 Cq. linealis 0 0 0 2 3.2 17 5.6 2.8 16.25 6 0.2 SE 0 0 0 2 2.478 16.669 5.354 2.8 15.585 5.01 0.2 Cx. annulirostris 0 0 0 1.2 1.8 1.25 5.8 11.8 1.25 6.8 0 SE 0 0 0 0.97 1.356 0.75 3.184 6.264 0.947 4.116 0 Cx. australicus 0 0 0.4 4.62 8.8 0.25 0 0 0 0 0 SE 0 0 0.4 3.914 5.305 0.25 0 0 0 0 0 Cx. globocoxitus 0 0.8 0.4 8.4 11.6 9.25 16.8 15.2 0.75 1.4 4.6 SE 0 0.8 0.245 5.446 5.24 5.529 12.101 11.07 0.25 0.748 3.4 Cx. molestus 0 0.6 0 0.8 2.4 0.75 1 0 2 25.8 1.2 SE 0 0.6 0 0.8 0.872 0.479 0.775 0 1.684 24.309 0.8 Cx. quinquefasciatus 0 0.8 0.2 0.2 0.4 10 0.2 0 0.5 0.4 0 SE 0 0.8 0.2 0.2 0.4 9.028 0.2 0 0.289 0.4 0 Ma. uniformis 0 0 0 0 0 0 0.2 0 0 0 0.2 SE 0 0 0 0 0 0 0.2 0 0 0 0.2 Tp. atripes 0 0 0 0 0 0 0 0.8 0 0 0 SE 0 0 0 0 0 0 0 0.8 0 0 0 Unidentifiable 0 0.2 0 10.42 0 0.25 0.2 0 0 0.8 0 SE 0 0.2 0 9.922 0 0.25 0.2 0 0 0.8 0 Male 0.2 0.2 0 0.6 3.4 1 2.2 0.2 1.25 1 0 SE 0.2 0.2 0 0.6 2.271 1 1.744 0.2 0.947 1 0 no captures 0 0 0 0 0 0 0 0 0 0 0 Trap failures 0 0 0 0 0 1 0 0 1 0 0 Total Adults 28.8 123.2 531.8 437.76 146.8 73.25 358.4 64.4 29.5 60.6 12 SE 22.659 75.207 450.787 368.193 85.632 43.414 111.025 31.788 21.911 27.316 3.688 n=5 n=5 n=5 n=5 n=5 n=4 n=5 n=5 n=4 n=5 n=5

117 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. – Larvae Data.

Mosquito Larval Dipping and Treatment: The Rural City of Murray Bridge. Table 9.3. Results of Larval Dipping within The Rural City of Murray Bridge.

Site Larvae Site Trip Date Condition present Ae. camptorhynchus Cx. australicus Cx. globocoxitus Density MB2L10 Other 11/8/2016 Full Yes * Medium MB2L23 Other 11/8/2016 Full Yes * Medium MB2L24 Other 11/8/2016 Full Yes * High MB2L14 Other 11/8/2016 Full Yes * Medium MB1L21 Other 11/8/2016 Full Yes * Medium MB1L18 Other 11/8/2016 Full Yes * Medium MB1L19 Other 11/8/2016 Full Yes * High MB1L19a Other 11/8/2016 Full Yes * High MB1L19b Other 11/8/2016 Full Yes * High MB1L19c Other 11/8/2016 Full Yes * High MB1L20 Other 11/8/2016 Full Yes * High MB1L20a Other 11/8/2016 Full Yes * High MB1L20b Other 11/8/2016 Full Yes * High MB1L9 Other 11/8/2016 Full Yes * Low MB1L3 Other 11/8/2016 Full Yes * Low MB1L6 Other 11/8/2016 Full Yes * Low MB1L4 Other 11/8/2016 Full Yes * Low MB2L3 1 27/8/2016 Full Yes * High MB2L6 1 27/8/2016 Full Yes * High MB2L9 1 27/8/2016 Full Yes * High MB5L3 2 20/9/2016 Full Yes * High MB4L5 2 20/9/2016 Full Yes * Medium MB2L6 2 20/9/2016 Full Yes * Medium MB2L9 2 20/9/2016 Full Yes * Medium MB5L2 2 20/9/2016 Full Yes * High MB5L3 2 20/9/2016 Full Yes * High MB4L5 2 20/9/2016 Full No MB1L9 3 15/10/2016 Full Yes * High MB1L10 3 15/10/2016 Receding No MB1L11 3 15/10/2016 Receding No MB1L21 3 15/10/2016 Full Yes * High MB1L22 3 15/10/2016 Full Yes * Medium MB1L23 3 15/10/2016 Full Yes Medium MB4L5 4 8/11/2016 Full Yes * * Medium MB1L3 4 8/11/2016 Full Yes * Medium MB1L6 4 8/11/2016 Full Yes * Medium MB1L9 4 8/11/2016 Full Yes * High MB1L13 4 8/11/2016 Full Yes * High MB1L14 4 8/11/2016 Full Yes * High MB2L2 4 8/11/2016 Full No MB2L10 4 8/11/2016 Full Yes * High MB2L23 4 8/11/2016 Full Yes * High MB1L3 5 3/12/2016 Receding No MB1L6 5 3/12/2016 Receding No MB1L9 5 3/12/2016 Receding No MB1L6 7 12/1/2017 Full Yes * Medium MB1L9 7 12/1/2017 Full No MB1L22 7 12/1/2017 Full Yes * High MB1L9 8 7/02/2017 Full No MB1L6 8 7/02/2017 Full Yes * Low MB2L10 8 7/02/2017 Full No MB1L3 8 7/02/2017 Full No MB1L4 8 7/02/2017 Full No MB1L8 11 22/4/2017 Full Yes * MB1L9 11 22/4/2017 Filling Yes * Low MB2L10 11 22/4/2017 Full Yes * Low

118 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge – Larvae Data

Murray Bridge larvicide treatments.

The conditions over winter and into spring were enough to result in a number of a number of Ae. camptorhynchus larvae sites remaining until spring and requiring treatment (Table 9.3). In anticipation of potential problems, these sites were treated with S-Methoprene briquettes and/or sprayed with BtI at the beginning of August prior to the commencement of the season (Table 9.4). Monitoring of larvae sites continued throughout the season, particularly at known problem sites and locations that had S- Methoprene briquette holders strategically placed in previous seasons. Periods of above average rainfall followed this treatment, however, few larvae sites required additional treatment as S-Methoprene briquettes remained active. Late in the season, additional S-Methoprene briquettes were laid at known spring larval sites of Ae. camptorhynchus as a preventative measure in order to reduce over-wintering larval populations of this species (Table 9.4). Sites north of Murray Bridge particularly along Toora Road have been problem sites for a number of years as they often have very high densities of Ae. camptorhynchus and were preventatively treated late in the season. Fortunately, these sites tend to be in roadside channels and pools easily accessed and controlled with a combination of S-Methoprene briquettes and the application of liquid BtI. In addition to the monitoring and control efforts by the Mosquito a Public Health Research Group with the continuation of the informal relationship with SA Water. Harry Roberts from SA Water has been conducting active monitoring and treatment of larvae sites on SA Water land north of Murray Bridge particularly along Toora Road and Swamp Road (Table 8.5). SA Water has received monitoring data and arboviral screening data to assist them in understanding the mosquito communities along the river and where their activities or landholdings impact the community.

119 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. – Larvae Data.

Table 9.4. Larvicide application in Murray Bridge Council during the 2016-17 season.

Site Date Product Quantity Site Date Product Quantity MB2L10 11/8/2016 Briquettes 7 MB1L10 15/10/2016 Briquettes 3 MB2L23 11/8/2016 Briquettes 7 MB1L11 15/10/2016 Briquettes 1 MB2L24 11/8/2016 Briquettes 1 MB1L22 15/10/2016 Briquettes 13 MB2L14 11/8/2016 Briquettes 20 MB1L23 15/10/2016 Briquettes 4 MB1L21 11/8/2016 BtI 300 ml MB5L7 15/10/2016 Briquettes 5 MB1L18 11/8/2016 Briquettes 4 MB1L6 12/1/2017 Briquettes 3 MB1L19 11/8/2016 Briquettes 7 MB1L22 12/1/2017 Briquettes 18 MB1L19a 11/8/2016 Briquettes 1 MB1L3 22/4/2017 Briquettes 1 MB1L19b 11/8/2016 Briquettes 1 MB1L6 22/4/2017 Briquettes 11 MB1L19c 11/8/2016 Briquettes 1 MB1L8 22/4/2017 Briquettes 6 MB1L20 11/8/2016 Briquettes 8 MB1L9 22/4/2017 Briquettes 23 MB1L20a 11/8/2016 Briquettes 1 MB1L18 22/4/2017 Briquettes 1 MB1L20b 11/8/2016 Briquettes 1 MB1L21 22/4/2017 Briquettes 1 MB1L9 11/8/2016 BtI 200 ml MB1L22 22/4/2017 Briquettes 8 MB1L3 11/8/2016 BtI 200 ml MB2L10 22/4/2017 Briquettes 10 MB1L6 11/8/2016 BtI 200 ml MB2L14 22/4/2017 Briquettes 25 MB1L4 11/8/2016 BtI 100 ml MB1L19 22/4/2017 Briquettes 8 MB2L3 27/8/2016 Briquettes 1 MB1L19a 22/4/2017 Briquettes 1 MB2L6 27/8/2016 Briquettes 13 MB1L19b 22/4/2017 Briquettes 1 MB2L9 27/8/2016 Briquettes 23 MB1L19c 22/4/2017 Briquettes 1 MB5L3 20/9/2016 Briquettes 7 MB1L20 22/4/2017 Briquettes 5 MB4L5 20/9/2016 Briquettes 27 MB1L20a 22/4/2017 Briquettes 1 MB2L6 20/9/2016 Briquettes 23 MB1L20b 22/4/2017 Briquettes 1 MB2L9 20/9/2016 BtI 200 ml MB5L2 20/9/2016 Briquettes 4 MB5L3 20/9/2016 Briquettes 4 MB1L9 15/10/2016 Briquettes 40

Table 9.5. Additional treatment by Harry Roberts SA Water.

australicus

camptorhynchus

Date Location

Ae. Ae. Cx. Treatment 20/10/2016 Swamp Rd SE * * 20/10/2016 Swamp Rd SW * 20/10/2016 Swamp Rd NE * 20/10/2016 Toora E * 2/11/2016 Swamp/Pump Rd * y 30/11/2016 Swamp/Pump Rd * y 4/01/2017 Swamp/Pump Rd * y 1/02/2017 Swamp/Pump Rd * y 1/03/2017 Swamp/Pump Rd * y 5/04/2017 Swamp/Pump Rd * y 3/05/2017 Swamp/Pump Rd * y

1 cup Methoprene pellets every 100 m

120 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge.

Discussion of Murray Bridge Results.

Adult mosquitoes. A total of 9, 230 (n=53) mosquitoes were trapped in the Rural City of Murray Bridge during the 2016-17 season, this was an increase on the previous seasons total mosquito catch (6,127, n=49 see Table 9.5). This was the fourth highest total adult female mosquito catch for the council and was over twice the historic average (corrected for n=55) over the previous 17 years of monitoring.

The composition of the mosquito catches and its distribution across the season in the Rural City of Murray Bridge (Chart 9.4) differed from the three upper river councils (Charts 5.4, 6.3 and 7.5) and the Mid-Murray Council (Chart 8.5). The pattern of abundance in Murray Bridge Council was most similar to the that seen at Port Mannum in the lower Mid-Murray Council. The difference was in the size and timing of each peak in abundance. The early season spike in adult female mosquitoes also far exceeding the long-term trends, however, it occurred a month earlier and exceeded the second period of elevated abundance which also occurred in January (Chart 9.6). The relatively high number of mosquitoes extended to March 2017, with mosquito numbers exceeding long-term means or at least approximating them. During mid-summer, there was higher than average numbers, particularly in January and to a lesser extent February. The composition of the mosquito community in the lower River Councils was similar to that seen in the Mid-Murray Council (Table 12.2). Unlike in the upper river councils, the lower river mosquito communities were dominated by a single species Ae. camptorhynchus, over ≈83% of the mosquito catch in each of the lower river councils was comprised of this species while Cx. australicus only contributed a small component to the overall mosquito community. In the Rural City of Murray Bridge Ae. camptorhynchus was clearly the most common species of mosquito, making up ≈85% of the total council adult mosquito catch. No other species exceed 5% of the mosquito catch in the council and the second most abundant species Cx. globocoxitus contributed only 3.6% of the total catch. The largest mosquito numbers were recorded early in the season with the highest numbers 2, 6598 (n=5) caught during October a month earlier that the long-term peak in abundance (Table 9.1). High mosquito numbers in spring are typical of the Rural City of Murray Bridge and although mosquito numbers generally peak in November and are in decline by December (Chart 9.6). As with the previous season, the highest overall seasonal catch was recorded at Wellington (MB5) with 70 % of all individual caught at this site 6, 485 (n=11) over the season. Mypolonga School (MB1) recorded the second highest catch within the council with 1, 186 (n=10) individuals

121 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. -Discussion. or 21.7% of all adult mosquitoes caught within the council. While Murray Bridge Golf Course (MB3) yielded the third highest mosquito catch for the season with 830 (n=11) mosquitoes caught.

Species worthy of consideration include:

Ae. camptorhynchus (7, 845, or 85 % of total catch) was the most common mosquito captured overall and was also the most common mosquito at each trap site within the council area. Ae. camptorhynchus was caught early in the season starting from the first trap run in August 2016 with 144 (n=5) individuals caught. Ae. camptorhynchus numbers then increase through September to peak at 2, 653 (n=5) before declining through to January 2017 where a second lesser peak in abundance of 1, 614 (n=5) occurred. This second increase in Ae. camptorhynchus coincided with a record Ae. camptorhynchus catch a Port Mannum (Chart 8.5) and elevated catches within the Coorong District Council (Chart 10.5). The number of Ae. camptorhynchus then declined into the warmer months of January and February and April although some elevated numbers were recorded in March 2016 (Chart 9.4). As with the previous season, the proportion of the catch and the number of individuals caught varied across the council and the highest numbers of Ae. camptorhynchus were recorded in Wellington with 5, 884 (n=11) individuals being caught at this site or 91% of all individuals caught this season. Ae. camptorhynchus was constituted a high proportion of individuals trapped at Murray Bridge Golf Course (MB3) comprising 89.2 % of individuals at this location or 740 individuals of the 830 (n=11) mosquitoes trapped at this location. The third highest catch of Ae. camptorhynchus this season came from Mypolonga (MB1) where 677 (n=10) individuals were identified, this constituted 57% of all individuals caught at this location and contributed 8.6 % of all individuals caught within the council this season. Ae. camptorhynchus was also a major part of the mosquito community at Jervois (MB4) where it constituted 78.6 % of the mosquito community (517 individuals and 6.6 % of individuals in Council) Cx. globocoxitus (336, or 3.6% of total catch) was the second most abundant species trapped during the 2016-17 season. This species was more common from November to February 2017 (Chart 9.5). The broad mid-season peak in abundance, reached only 84 individuals in January however, over 76 individuals were also recorded in March. Cx. globocoxitus remained most abundant at the Mypolonga School site (MB1) with nearly 60 % of individuals of this species coming from this trap site. This species also made up around 17 % of all individuals from this site. Cx. globocoxitus was also caught in reasonable numbers at Wellington (MB5, 49

122 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. - Discussion. mosquitoes or 0.8% of the catch at this site) and the Jervois Bowling Club (MB4, 59 mosquitoes 9% of the catch at this site). Cq. linealis (232, or 2.5 % of total catch) this species was the third most abundant species identified in the Murray Bridge Council Area during 2016-17. Cq. linealis as with the previous seasons was almost exclusively caught at Wellington (MB5, 95.2% of the total species catch) during the middle of the season. This species is hard to manage due to larval sites being difficult to identify. The larvae of Cq. linealis have a modified syphon that can pierce the roots of aquatic plants and allow it to obtain their oxygen through the plant. Therefore, dipping for larvae is almost impossible as a method of identifying larval sites and control of larvae sites is invariably done by trial and error. An. annulipes (212 or 2.3% of total catch) this species was the fourth most abundant species identified in the Murray Bridge Council Area during 2016-17. This species was quite common in the upper river councils due to its preference for semi-permanent flooded pools. This species was caught in highest numbers in November 2016 and was caught I highest numbers at MB5 Wellington Caravan Park where 75% of all individuals were trapped. Cx. annulirostris (147, or 1.6% of total catch) This species was only an exceptionally minor component of the mosquito fauna captured over the 2016-17 season and was the sixth most abundant species within the council. This is compared to the long-term trend being around 0.8% of the total catch for this council. Just over half of all individuals (78, 53 % of those caught across the council) were caught at the Mypolonga School site (MB1), This species is important as it is considered a major vector of arbovirus in inland Australia. Ae. notoscriptus (79, or 0.86 % of total catch) was only a small proportion of the total council catch. This species uses small water bodies such as containers for larvae sites and only disperses short distances. Although only small in number this species may be locally abundant and are often found to be the cause urban complaints. This species was most numerous at the Wellington Caravan Park MB5.

123 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge. -Discussion.

Table 9.5. Summary of all monitoring seasons, Murray Bridge Council. FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/2003 2003/ 2004 2004/ 2005 2005/ 2006

Rainfall Events Oct. Feb. Oct. Wet spring January (70 mm) Aug & Oct Peak in Dec winter/spring River Levels No data Peaks, Oct, Dec. No peak No peak Slightly elevated No peak Total female Mosquitoes 2, 810 (n=43) 1, 930 (n=53) 2, 917 (n=53) 1, 463 (n=53) 3, 171 (n=53) 3, 406 (n=53) 9, 502 (n=54) Mosquito Peak October Sept. Nov/ Dec. April Dec November November Ae. camptorhynchus & Ae. camptorhynchus & Ae. camptorhynchus & Dominant Species Ae. camptorhynchus. Ae. camptorhynchus. Ae. camptorhynchus. Ae. camptorhynchus. Cx. quinquefasciatus Cx. quinquefasciatus Cx. quinquefasciatus Reported arbovirus infections ~5 (RRV) ~6 (RRV) ~4 (RRV) ~1 (RRV) ~2 (RRV) ~1 (RRV) ~14 (RRV)

FEATURE 2006/ 2007 2007 /2008 2008 /2009 2009 /2010 2010/ 2011 2011/ 2012 2012/ 2013

Rainfall Events January/April below average Aug, Nov/Dec July/Sept/Nov/April Aug-Dec, & March Dec & March May-July Raised downstream pools in Raised from Aug/ Nov, High until October, Variable below locks in River Levels No peak No peak No peak Summer Feb & March peak in Feb. January pulse, April flood. late 2012 Total female Mosquitoes 1, 553 (n=54) 768 (n=54) 1, 147 (n=53) 2, 255 (n=54) 10, 896 (n=54) 2, 223 (n=54) 3, 612 (n=53) Mosquito Peak Nov/ Feb October January November April October/ January November / March September/ February Ae. camptorhynchus & Ae. camptorhynchus& Ae. camptorhynchus& Ae. camptorhynchus/ Dominant Species Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Cx. quinquefasciatus Ae. notoscriptus Ae. notoscriptus Cx. annulirostris Reported arbovirus infections 6 (RRV) 10 (RRV),8 (BFV) 8 (RRV),5 (BFV) 8 (RRV), 1 (BFV) 49 (RRV), 6 (BFV) 9 (RRV), 2 (BFV) 8 (RRV), 7 (BFV)

FEATURE 2013/ 2014 2014/ 2015 2015/ 2016 2016/2017

Rainfall Wet winter and February winter /Jan March September River Levels raised downstream of Lock Raised below Locks in spring Lower lakes high in spring Unregulated flow late 2016 Total female Mosquitoes 9, 598 (n=54) 3, 444 (n=47) 6, 127 (n=49) 9, 230 (n=53) September/ November/ September/ December & September/October & Mosquito Peak October/ January March into April January December Dominant Species Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Reported arbovirus infections 2 (RRV), 3 (BFV) None confirmed 1 (RRV), 1 (BFV) 16 (RRV, 15 probables, 1 confirmed)

124 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge.

COMMENTS.

Periods of average precipitation over the 2016-17 season was enough to activate a number of known Ae. camptorhynchus larvae sites and keep them active over much of the season. In expectation of potential issues with regard to this species a late winter control trip was undertaken prior to the commencement of trapping in late August 216 in order to assess larvae sites and apply control measures. Larvae control and surveillance were focused on the known highly productive larvae sites to the north of the major population centre of Murray Bridge, due to their proximity to the major population centre. These sites are managed with a combination of S-Methoprene briquettes and/or sprayed with BtI. Permanent S-Methoprene briquette holders can provide more efficient control of known problem larvae sites as they allow for rapid assessment of briquette condition and reduce wastage trough submergence in sediment. These stations can also be recharged when the larvae site is dry providing control when the site is subsequently flooded. The number of mosquitoes caught within the Rural City of Murray Bridge over the 2016- 17 season was slightly more than twice the long-term means of 4, 281 mosquitoes (adjusted for n=53) over the previous 17 years of monitoring. This was the fourth highest number of mosquitoes caught over a season the highest being 2010-11 in this season there was a high river with the significant overbank flow. Interestingly the composition of mosquito collections and their distribution across the season in the Rural City of Murray Bridge was similar to that seen at around Mannum and in the Alexandrina Council on the eastern coast of the lower lakes (Table 12.2). Consistent with historic records the dominant mosquito species within the Rural City of Murray Bridge was Ae. camptorhynchus, this species was most abundant at Wellington Caravan Park, although this species was well represented at all remaining sites. Ae. camptorhynchus season increased in numbers early in the season, then this species persisted throughout the season although, numbers declined somewhat from March, through the remainder of the season. Unfortunately, an increase in the level of the lower lakes and/or higher than average rainfall may have contributed to suitable habitat for Ae. camptorhynchus larvae particularly around the lower lakes. This may have contributed to the unseasonably high numbers of this species during mid-summer which is quite atypical. There was also a comparatively high proportion of Ae. camptorhynchus in the mosquito catch trapped at the Murray Bridge Golf Course this season; this was despite the control efforts in the surrounding area. In the Rural City of Murray Bridge, there were 16 notifications of RRV (15 probable, 1 confirmed) and no cases of BFV reported attributed to the 2016-17 season. There was a peak in reported date of onset was in January 2017, with seven probable notifications.

125 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Result: The Rural City of Murray Bridge.

This season the new passive mosquito trap was again trailed utilising a new method for screening mosquitoes for arboviruses. Within Rural City of Murray Bridge area, a passive trap was deployed adjacent the Department of Health’s ‘Sentinel Chicken Flocks’. In addition to the Passive Mosquito Trap The Healthy Environments, Healthy People Research Group placed FTA cards into a portion of the regular EVS trapping program. There were three arboviral detections within the council this season, two from the Wellington Caravan Park and one from Mypolonga MB1. The detection of RRV from the EVS trap located at Wellington Caravan Park triggered increased deployment of FTA cards in the following months. The significance of the information gained from this trial and the usefulness of these methods are being considered and more widespread trials in future years may result.

126 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 9. Results: The Rural City of Murray Bridge.

LOCAL RECOMMENDATIONS.

Mid-winter recharging S-Methoprene briquette stations at known problem Ae. camptorhynchus larvae sites at least around Murray Bridge to be conducted mid-late winter. More extensive treatment to be considered if winter rains are above average. Sites along Lagoon/Toora Road require continuous attention as roadside channels quickly fill forming long narrow water bodies suitable for Ae. camptorhynchus larvae. The control of these sites is problematic as they are continually modified by heavy machinery and bogged cars. The area requires continual monitoring throughout the season and treatment with S-Methoprene briquettes or BtI. Permanent well designed physical modification of this location would reduce the impact of the larva sites at this location on the nearby residents. Continued additional investigation of potential Ae. camptorhynchus larvae sites should be conducted in the area surrounding the Rural City of Murray Bridge this is an ongoing process. The management Ae. camptorhynchus larvae sites should be improved, with co-operation from the landholders (if appropriate) and the installation of permanent briquette stations should be increased. This would provide more effective control of problematic sites. It is important to strive for the environmental health effects of environmental flows and wetland inundation is considered by water managers when planning. The mosquito communities’ response needs to be a consideration when undertaking these activities. Consulted of EHO’s and factored in the monitoring of the mosquito populations (both larva and adult) when conducting these activities is the ideal. Communication channels are being developed but this is an ongoing issue and requires continual improvement; this will take some time to resolve as new water management practices evolve and health issues require consideration. The Passive trap system is a promising technology, however, increased placement of FTA cards in EVS traps may be a more effective tool for arboviral surveillance. The passive trap technology may be better utilised in regions not serviced by regular EVS collections supplemented with FTA cards

127 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

10. RESULTS FOR THE COORONG DISTRICT COUNCIL. Adult trap site descriptions.

C 1. Tailem Bend Golf Club Longitude: E139 27.496 Latitude: S35 15.906

C 2. Marina Wellington Longitude: E139 23.538 Latitude: S35 19.468

128 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council

C 3. Poltalloch Road Longitude: E139 18.953 Latitude: S35 29.397

C 4. Waltowa Swamp Culvert Longitude: E139 22.538 Latitude: S35 36.554

129 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council

C 5. Meningie Area School Lake Longitude: E139 20.596 Latitude: S35 41.075

130 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council

Weather Data: The Coorong District Council.

Weather data were supplied by the Bureau of Meteorology Weather Station a Meningie (Weather Station 24518) and Tailem Bend (Weather Station 24536). Overall the 2016-17 season was characterised by mostly warmer than average nights over the majority of the season and much warmer than average days (Chart 10.2). The exceptions to the comparatively warm nights were November which had an average minimum temperature half a degree less than would be expected biased on historic data. While December was an average month with temperatures equalling the historic means. The monthly average minimum daily temperature exceeded the long-term means over all other months at the Meningie weather station. The month with the relatively warmest nights was January which exceeds historic means by 1.2 ºC on average. The daytime temperatures were a little more complex. The first two months of winter approximated the long term means, however, August days were 0.8 ºC warmer than the long-term mean. This was followed by two months of comparatively cooler months with average daily temperatures around 1.5 ºC below the historic means or the months, the cooler conditions continued into November with days around half a degree below trend. Over the next two months, the daytime temperatures became increasingly warm as measured against the historic mean with monthly averages a degree and 1.6 ºC above trend during December and January. As with other councils, February was relatively mild with days approximating the long term means, however, March again had an average daytime temperature well over a degree warmer than long-term trends (Chart 10.2). The 14-day moving mean maximum temperature (14DMADMax) recorded at Meningie Weather Station (Weather Station 24518) first increased above 20 ºC late October 2016 a month later than the previous season. It then remained above 20 ºC until the end of the season, the last week of April (Chart 10.1). The 14DMADMax moved to remain over 25 ºC consistently for two prolonged periods during the season; the first for over eight weeks from the middle of December until the middle of February. This was followed by around a week of cooler conditions after which 14DMADMax rose again to remain over 25 ºC consistently for a further four weeks, until the last week of March. few days of November until late January 2016. The 14DMADMin increased to over 15 ºC and remained there for a period on four occasions each lasting different period. The first and longest of these events lasted from the last week of December 2016 through to the middle of January a period of nearly four weeks. The second period was also the second longest period lasting just under two weeks spanning a period 131 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council

in the first two weeks of February. The last two periods were only a few days each and occurred at the beginning and end of March 2017. Rainfall data were supplied by the Bureau of Meteorology Weather Stations at Meningie and Tailem Bend (Weather stations 24518 and 24536 respectively) distribution of rain was broadly similar at the two locations (Chart 10.3 and Chart 10.4). During the season, total monthly precipitation at Meningie (620.8 mm) and Tailem Bend (516.8 mm), exceeded the historic mean (469.5 mm and 375 mm respectively). Precipitation was not distributed evenly across the season, with monthly totals failing to exceed historic means in March, November and August at both stations and October at Tailem Bend. Precipitation exceeded historic records during all other months of the normal season (Chart 10.3).

132 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Weather Data.

Chart 10.1. Meningie Weather Station (24518) Maximum and Minimum Temperature with the 14-day moving average from May 2015 to April 2016.

C 25 °

Temperature 15

Date Chart 10.2. Meningie Weather Station (24518) Monthly Mean Maximum and Minimum Temperature May 2015 to April 2016 compared to historic means (solid line). 100 Total precipitation Historic Mean 90

Precipitation (mm) Precipitation 30

0 May June July August September October November December January February March April Month

133 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Weather Data.

Chart 10.3. Total Monthly Precipitation (mm) at Meningie Weather Station (24518) during the 2016-17 trapping period compared with the historic mean. 40 Mean max temp 2016-17 Historic mean Mean min temp 2016-17 Historic min

25 C ° 20

15 Temperature Temperature

0 May June July August September October NovemberDecember January February March April Month Chart 10.4. Total Monthly Precipitation (mm) at Tailem Bend Weather Station (24536) during the 2016-17 Trapping Period Compared with the Historic Mean.

120.00 Total precipitation Historic Mean

100.00

80.00

60.00

40.00 Precipitation (mm) Precipitation

20.00

0.00 May June July August September October NovemberDecember January February March April Month

NOTE: Figures above run from May 2016, four months before the start of this sampling season.

134 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council.

Adult mosquito trapping results: The Coorong District Council. Chart 10.5. Coorong Council Area, total adult, and Ae. camptorhynchus female adult mosquitoes caught in the 2016-17 season.

135 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. – Adult Data.

Chart 10.6. Coorong Council Area, total and secondary species of adult mosquitoes caught in the 2016-17 season.

Chart 10.7. Coorong Council Area, Average mosquito catch for the 2016-17 season compared to the mean for the previous 17 years.

136 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. – Adult Data.

Table 10.1. Totals for the five traps in Coorong Council Area.

Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 17/12/16 12/01/17 7/02/17 2/03/17 27/03/17 23/04/17 Season Total Ae. alboannulatus 0 0 0 0 0 0 0 1 3 10 1 15 Ae. camptorhynchus 35 335 634 3629.4 617 2097 2097 70 239 5 1 9759.4 Ae. notoscriptus 0 1 1 1 0 0 0 0 1 1 1 6 Ae. postspiraculosis 0 0 4 0 0 0 0 0 0 0 0 4 An. annulipes 0 2 131 807 235 42 42 5 1 0 0 1265 Cq. linealis 0 0 0 0 2 1 1 0 30 0 0 34 Cx. annulirostris 0 0 0 0 2 37 37 14 23 4 0 117 Cx. australicus 1 0 52 0 1 0 0 0 0 0 0 54 Cx. globocoxitus 6 4 15 34.1 99 53 53 11 9 0 1 285.1 Cx. molestus 6 19 36 13 1 1 1 6 5 22 26 136 Cx. quinquefasciatus 0 2 24 1 2 0 0 0 1 0 2 32 Unidentifiable 0 0 7 2 0 0 0 0 2 0 0 11 Male 0 0 7 0 0 0 0 0 0 0 0 7 no captures 1 0 0 0 1 0 0 0 0 2 1 Trap failure 1 0 0 0 2 0 0 1 0 1 0 Total Adults 48 363 904 4487.5 959 2231 2231 107 314 42 32 11718.5 n=4 n=5 n=5 n=5 n=3 n=5 n=5 n=4 n=5 n=4 n=5 Total (n=50)

137 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Adult Data.

Table 10.2. Average Catch for the five traps in Coorong Council Area.

Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 17/12/16 12/01/17 7/02/17 2/03/17 27/03/17 23/04/17 Ae. alboannulatus 0 0 0 0 0 0 0 0.25 0.6 2.5 0.2 SE 0 0 0 0 0 0 0 0.25 0.4 1.893 0.2 Ae. camptorhynchus 8.75 67 126.8 725.88 205.67 419.4 419.4 17.5 47.8 1.25 0.2 SE 3.199 41 62.918 655.71 178.29 282.277 282.277 12.386 34.994 1.25 0.2 Ae. notoscriptus 0 0.2 0.2 0.2 0 0 0 0 0.2 0.25 0.2 SE 0 0.2 0.2 0.2 0 0 0 0 0.2 0.25 0.2 Ae. postspiraculosis 0 0 0.8 0 0 0 0 0 0 0 0 SE 0 0 0.8 0 0 0 0 0 0 0 0 An. annulipes 0 0.4 26.2 161.4 78.33 8.4 8.4 1.25 0.2 0 0 SE 0 0.4 19.846 160.9 77.834 5.644 5.644 0.947 0.2 0 0 Cq. linealis 0 0 0 0 0.67 0.2 0.2 0 6 0 0 SE 0 0 0 0 0.667 0.2 0.2 0 5.753 0 0 Cx. annulirostris 0 0 0 0 0.67 7.4 7.4 3.5 4.6 1 0 SE 0 0 0 0 0.333 4.456 4.456 1.849 2.337 0.707 0 Cx. australicus 0.25 0 10.4 0 0.33 0 0 0 0 0 0 SE 0.25 0 4.377 0 0.333 0 0 0 0 0 0 Cx. globocoxitus 1.5 0.8 3 6.82 33 10.6 10.6 2.75 1.8 0 0.2 SE 0.958 0.583 1.844 4.719 31.512 5.546 5.546 0.854 1.114 0 0.2 Cx. molestus 1.5 3.8 7.2 2.6 0.33 0.2 0.2 1.5 1 5.5 5.2 SE 0.866 3.8 6.46 2.6 0.333 0.2 0.2 1.5 0.775 3.404 5.2 Cx. quinquefasciatus 0 0.4 4.8 0.2 0.67 0 0 0 0.2 0 0.4 SE 0 0.245 3.007 0.2 0.333 0 0 0 0.2 0 0.245 Unidentifiable 0 0 1.4 0.4 0 0 0 0 0.4 0 0 SE 0 0 0.98 0.4 0 0 0 0 0.4 0 0 Male 0 0 1.4 0 0 0 0 0 0 0 0 SE 0 0 0.98 0 0 0 0 0 0 0 0 no captures 1 0 0 0 1 0 0 0 0 2 1 Trap failures 1 0 0 0 2 0 0 1 0 1 0 Total Adults 12 72.6 180.8 897.5 319.67 446.2 446.2 26.75 62.8 10.5 6.4 SE 3.937 39.941 84.26 816.756 239.473 296.592 296.592 15.516 38.053 4.574 5.4 n=4 n=5 n=5 n=5 n=3 n=5 n=5 n=4 n=5 n=4 n=5

138 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. – Larvae Data.

Mosquito Larval Dipping and Treatment: The Coorong District Council. Table 10.3. Results of Larval Dipping within The Coorong District Council.

Site Trip Date Site Condition Larvae present Ae. camptorhynchus Density C3L4 1 27/8/2016 Full Yes * High C3L5 1 27/8/2016 Full Yes * High C5L1 1 27/8/2016 Full Yes * High C5L3 1 27/8/2016 Full Yes * Medium C5L4 1 27/8/2016 Full Yes * High C5L17 1 27/8/2016 Full Yes * High C5L18 1 27/8/2016 Full Yes * High C5L3 2 20/9/2016 Full Yes * High C5L12 2 20/9/2016 Full Yes C5L17 2 20/9/2016 Full Yes * High C5L18 2 20/9/2016 Full Yes * High C5L19 2 20/9/2016 Full Yes * High C5L7 2 20/9/2016 Full No C3L9 2 20/9/2016 Filling Yes * High C2L7 2 20/9/2016 Full No C2L1 2 20/9/2016 Filling No C5L19 3 14/10/2016 Full Yes * Medium C3L5 11 22/4/2017 Filling Yes * Low C5L3 11 22/4/2017 Full Yes * Medium C5L17 11 22/4/2017 Filling Yes * Medium C5L18 11 22/4/2017 Filling Yes * Medium

Coorong District Council larvicide treatments.

The cumulative total precipitation over winter was slightly greater than the long-term means at both Tailem Bend and Meningie. The winter rainfall resulted in several active larvae sites being identified (Table 10.3) and treated around Meningie during August (Table 10.4). Treatment continued throughout spring with the above average rain in September resulting in a number of active larvae sites. The high river flows and increases the level of the lower lakes in October and again in December may have resulted in a number inaccessible larvae sites along the lake edge. This is probably the cause of the increase in both Ae. camptorhynchus, and An. annulipes during December and January 2017. December with the below average rainfall in the months that followed few larvae sites requiring additional treatment. Following the rain in December through to February 2017 (Chart 10.3) known larvae sites were monitored and additional S-Methoprene briquettes were found not to be required. At the end of the season known larval sites of Ae. camptorhynchus were selected around the Coorong District Council for prophylaxis treatment.

139 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. Larvae Data.

Table 10.4. Larvicide application in Coorong Council during the 2016-17 season.

Site Date Product Quantity C3L4 27/8/2016 Briquettes 15 BtI 200 ml C3L5 27/8/2016 Briquettes 8 BtI 200 ml C5L1 27/8/2016 Briquettes 1 C5L3 27/8/2016 Briquettes 10 C5L4 27/8/2016 Briquettes 14 C5L17 27/8/2016 BtI 200 ml C5L18 27/8/2016 BtI 100 ml C5L12 20/9/2016 BtI 100 ml C5L13 20/9/2016 BtI 100 ml C5L17 20/9/2016 BtI 200 ml C5L18 20/9/2016 BtI 200 ml C5L19 20/9/2016 BtI 300 ml C5L12 14/10/2016 Briquettes 3 C5L13 14/10/2016 Briquettes 2 C5L17 14/10/2016 Briquettes 20 C5L19 14/10/2016 Briquettes 4 C5L1 8/11/2016 Briquettes 2 C3L4 22/4/2017 Briquettes 20 C3L5 22/4/2017 Briquettes 14 C5L1 22/4/2017 Briquettes 2 C5L1 22/4/2017 Briquettes 4 C5L3 22/4/2017 Briquettes 24 C5L4 22/4/2017 Briquettes 18 C5L1 22/4/2017 Briquettes 1 C5L17 22/4/2017 Briquettes 21 C5L18 22/4/2017 Briquettes 1

140 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. – Larvae Data.

Discussion of Coorong Council results.

Adult mosquitoes. A total of 11, 718.5 (n=50) mosquitoes were trapped in the Coorong District Council during the 2016-17 season, this was 4.6 times the total number of mosquitoes caught in the council over the previous season 2, 443 (n=51, when adjusted for n), and around a third of the record adult trap numbers of 30, 236 mosquitoes (n=54 in 2013-14) (Table 10.5). The number of adult mosquitoes recorded in the 2016-17 season is slightly less than half the Coorong District Council long term mean of 6, 291 mosquitoes and around three times the median 2 682 (both adjusted for n=50). Mosquito numbers in the Coorong District Council during the 2016-17 season followed historic patterns, with a peak being recorded in the early in the season, numbers then gradually trailing off over late summer. However, the distribution in mosquito abundance was shifted into the warmer months with a peak in abundance occurring in November rather than the historic peak during September and numbers persisting later than a typical year. This pattern was also observed in the adjacent council The Rural City of Murray Bridge (Chart 9.4) however the distribution of mosquitoes in Alexandrina Council differed somewhat (Chart 11.2). As with previous seasons, the adult mosquito trap data was dominated by the cool weather species Ae. camptorhynchus contributing 83.3% of the total council adult mosquito catch for the 2016-17 season. This was around the long-term trends with 78% of all adult mosquitoes over the previous 17 years being this species. The warm weather mosquito Cx. annulirostris was contributed to 1% of adult trap collections this season, this is an important species to consider as it is considered to be an important vector of arbovirus. The remaining mosquitoes recorded this season were predominately comprised of An. annulipes which made up nearly 11 % the remainder were mostly made up of Cx. pipiens group of mosquitoes amongst others (Table 10.1). Overall 79% of all adult mosquitoes trapped in the council during 2016-17 were caught at Waltowa Swamp (C4, 9235 n=10) and 8.8% of the remainder came from Meningie School (C5, 1035 n=10). The remaining sites were fairly similar recorded comparatively few mosquitoes, Poltalloch Bluff (C4, 631 n=10), East Wellington (C2, 413 n=10) and Tailem Bend (C1, 404 n=11).

Species worthy of consideration include:

Ae. camptorhynchus (9, 759.4, or 83.3 % of total catch) was the most prevalent species of all adult mosquitoes identified during the 2016-17 season. This species was caught on the first trap run but in lower numbers that historic records, collections increased into around historic levels in

141 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Discussion.

October 2017 then continued to increase peaking in November. In the following month, Ae. camptorhynchus numbers then halved to an average of 400 per trap night but were maintained at this level in January. Collections then crashed and only approximated historic catches for the remainder of the season. Unlike the previous season the majority of Ae. camptorhynchus (80.3%) trapped in the council came from the Waltowa Swamp (C4, 9,759, n=10) where it constituted around 85 % of all the mosquitoes caught at this location. Ae. camptorhynchus was caught in moderate numbers at Meningie School (C5) with 8.4% of individuals of this species were caught, this was down from last season where over 45% of all Ae. camptorhynchus collections came from this location. The remaining locations all had collections between 344 and 404 Ae. camptorhynchus individuals, and had similar relative abundances of around 85 % with the exception of Poltalloch Bluff (C3) where this species only made up 64% of mosquitoes collected at this site. An. annulipes (1, 265, or 10.8% of total catch) this species was the second most abundant species caught within the council during the 2016-17 season this is at odds with previous seasons where this species only contributes around 3 % to collections within this council. Populations of An. annulipes were by and large confined to the Waltowa Swamp trap location (C4, 1, 205 n=10, 95.3 % of species catch) where it constituted 13 % of the collections at this location. An. annulipes was caught in small numbers across all other trap locations within the council. Across the season An. annulipes increased in abundance rapidly from a modest number in October to 807 individuals (n=5) collected in November when it was almost exclusively trapped at Waltowa Swamp. Following this numbers declined, with only a few individuals caught from February 2017. Cx. globocoxitus (285, or 2.4% of total catch) was the third most abundant species trapped within the Coorong District Council during the 2016-17 season. Cx. globocoxitus was found to have a similar distribution across the season to An. annulipes although the peak in abundance occurred during December rather than November. From early December numbers declined, however, Cx. globocoxitus was otherwise caught in low numbers over the whole season (Chart 10.6). This species has been found to be an indicator of arboviral activity in the upper river; it is presumed this presence of this species indicates the suitability of habitat for vector species in that area. Cx. globocoxitus was most abundant at Poltalloch Bluff (C3, 134 n=9), where 47% of all individuals of this species within the council were identified.

142 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Discussion.

Cx. molestus (136, or 1.2% of total catch) this species was the fourth most abundant species caught within the council during the 2016-17 season and in keeping with patterns established in previous years was almost exclusively caught at the Meningie school site (C5, 120 n=10, 88.2 of species catch). This is due to the proximity of a large drain that is utilised as a larvae site for this species. Cx. annulirostris (117, or 1% of total catch) this species is thought to be a major vector of arboviruses throughout inland Australia, In the 2010-11 season, this species became the second most numerous within the council. Only one percent of specimens were identified in collections from the council during the 2016-17 season, probably influenced by the average daytime temperatures during the early part of summer.

143 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council. - Discussion.

Table 10.5. Summary of all monitoring seasons, Coorong Council. FEATURE 1999/ 2000 2000/ 2001 2001/ 2002 2002/ 2003 2003/04 2004/2005 2005/2006 2006/2007

Rainfall Events Peak Feb. Oct. Mar. Aug. late Feb (63 mm) Aug, wet spring Peak Dec Oct, June. Jan. April River Levels No data Peaks, Oct, Dec. NA None No significant peak NA No apparent patterns Total female Mosquitoes 1, 964 (n=41) 4, 632 (n=55) 5, 024 (n=54) 1, 636 (n=51) 5, 987 (n=52) 1, 541 (n=54) 12, 918 (n=53) 3, 287 (n=50) Mosquito Peak Sept./ Mar. October Oct./ Nov. October Oct./ Nov. Sept/ Nov. Sept/Dec October Ae. camptorhynchus/ Dominant Species Ae. camptorhynchus. Ae. camptorhynchus. Ae. camptorhynchus. Ae. camptorhynchus. Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Cx. molestus Reported arbovirus infections ~1(RRV) ~20 (RRV) ~1 (RRV) None confirmed None confirmed 1 (RRV), 6(BFV) ~43 (RRV), 22 (BFV) 4 (RRV), 2 (BFV)

FEATURE 2007/2008 2008/2009 2009/2010 2010/2011 2011/2012 2012/2013 2013/2014

Rainfall Events Tracking mean Aug, Nov/Dec Peak April/ July/ Sept August and Nov to Feb Average Winter otherwise dry winter and February Receding river and Receding river and Lower Lakes increasing High until October, River Levels Lower lakes remain low Variable in late 2012 Variable in late 2013 lakes lakes November Jan, April flood. Total female Mosquitoes 1, 145 (n=53) 398 (n=52) 993 (n=51) 8, 302 (n=54) 5, 438 (n=48) 16, 423 (n=49) 29, 919 (n=54) Mosquito Peak Oct, Nov & March January Oct/ Nov. November Oct/ Nov. Sept/October Sept/October Ae. camptorhynchus/ Ae. camptorhynchus/ Dominant Species Cx. molestus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Cx. molestus Cx. annulirostris/ Cx. globocoxitus Reported arbovirus infections 7 (RRV), 3 (BFV) 10 (RRV), 6 (BFV) Nil 34 (RRV), 5 (BFV) 3(RRV), 2 (BFV) 3 (RRV), 2 (BFV) 2 (RRV), 2 (BFV)

FEATURE 2014/2015 2015/2016 2016/2017

Rainfall Events wet early winter/ Jan High summer (Jan/Feb) September River Levels Spring raised below locks Lower lakes high in spring Unregulated flow late 2016 Total female Mosquitoes 3, 223 (n=48) 2, 443 (n=51) 11, 718 (n=50) Mosquito Peak Sept/October Sept/March November Dominant Species Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus 25 (RRV, 21 probables, 4 Reported arbovirus infections 12 (RRV) 7 (RRV) confirmed), 1 (BFV)

144 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council.

COMMENTS. The Coorong District Council recorded slightly above average precipitation over winter 2016 at both Tailem Bend and Meningie Weather station. Higher than average precipitation in spring provided enough moisture for several known Ae. camptorhynchus larva sites to persist well into the season. These sites were treated over the first adult collect trip of 2016-17 during late-August and then monitored over the remainder of the season. In addition to rain-fed pools, a higher lake level (Chart 4.3) probably resulted in the inundation of sections of the lake edge activating Ae. camptorhynchus larvae sites around adjacent. Although female mosquito numbers were high at some sites within the council, overall Waltowa Swamp recorded the highest numbers of any trap site within the council with around 78.8% of all mosquitoes caught within the council over the 2016-17 season. The remaining sites contained between 404 female mosquitoes (n=11, 3.4% of the total council catch) at Tailem Bend and 1035 (n=10, 8.8% of the total council catch) at Meningie School. The remaining sites Poltalloch Bluff and East Wellington recorded 631 (n=9, 5.4% of the total council catch) and 413 (n=10, 3.5% of the total council catch) female mosquitoes the third and fourth highest numbers recorded within the Coorong Council. Overall mosquito numbers were below long-term trends in August and into September, numbers then increased to well above average in November and continued at this level into Summer. Collections remained well above average until February when then dropped to approximate long- term trends for the remainder of the season. Unlike the previous season when half of all mosquitoes were collected from the Meningie school site, this season the majority of collections derived from traps located outside population centres. The nuisance mosquito Cx. molestus remained low over most of the season, increasing at the time probably due to the local rain events. In the Coorong District Council, there were 25 cases of RRV reported (21 probable, 4 confirmed), with the majority (13) with an estimated date of onset in December 2016. There was also a further 7 notifications with an estimated date of onset January 2017. The majority of RRV notifications were also attributed to Meningie. This season the new passive mosquito trap was again trailed utilising a new method for screening mosquitoes for arboviruses. Within Coorong Council area a passive trap was deployed adjacent the Department of Health’s ‘Sentinel Chicken Flocks’ in Meningie. In addition to the Passive Mosquito Trap, The Healthy Environments, Healthy People Research Group placed FTA cards into a portion of the regular EVS trapping program. A positive result was obtained from an FTA card set in an EVS trap at Wellington Caravan Park during December, and the number of FTA cards set was increased in subsequent collections. This resulted in three more arboviral detections 145 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results The Coorong District Council.

(Table 4.3). The significance of the information gained from this trial and the usefulness of these methods are being considered and more widespread trials in future years may result.

146 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 10. Results: The Coorong District Council.

LOCAL RECOMMENDATIONS.

Irrespective of winter rains S-Methoprene briquette stations should be recharged and known problem Ae. camptorhynchus larvae sites treated in mid-winter, within the Coorong District Council. If winter rains are above average then more extensive treatment should be considered. Continued investigation of potential Ae. camptorhynchus larvae sites should be conducted in the area surrounding major population centres. The management Ae. camptorhynchus larvae sites are improved, with co-operation from the landholders (if appropriate) and the installation of permanent briquette stations increased. This would provide more effective control of problematic sites. Investigate areas around Waltowa Swamp in order to better understand mosquito ecology there this is problematic due to access. Establish permanent S-Methoprene stations at known problem larva sites within the council, particularly for sites that are active annually.

147 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

11. RESULTS FOR THE ALEXANDRINA COUNCIL. Adult trap site descriptions.

A. Milang Longitude: E138 58.246 Latitude: S35 24.504

A2. Clayton Longitude: E138 55.333 Latitude: S35 29.451

148 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council.

A3. Goolwa North Longitude: E138 47.575 Latitude: S35 29.849

A4. Goolwa Longitude: E138 46.838 Latitude: S35 30.178

149 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council.

A5. Port Elliot Longitude: E138 40.494 Latitude: S35 31.865

150 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council.

Weather Data: Alexandrina Council.

Total monthly precipitation data were supplied by the Bureau of Meteorology Weather Station located at the Goolwa Council Depot (Weather Stations 23718) represented in Chart 10.3. Overall the total annual precipitation to May 2017 within Alexandrina Council (641.2 mm) exceeded the long-term annual mean (468.1 mm) by 173.1 mm. The season itself was characterised by a wet start, with September and July precipitation somewhat higher than the long-term trends. This was followed up in January total precipitation around three times the long-term means. The remainder of 2016-17 was unremarkable with rainfall either approximating or falling short of long term trends (Chart 11.1). Temperature data was not recorded from this council and can be inferred from Murray Bridge and Coorong Councils. Chart 11.1. Total Monthly Precipitation (mm) at Goolwa Council Depot (23718) during the 2016-17 trapping period compared with the historic mean.

200 Total precipitation Historic Mean

180

160

140

120

100

80 Precipitation (mm) Precipitation

0 May June July August September October November December January February March April Month

151 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council.

Adult mosquito trapping results: The Alexandrina Council. Chart 11.2. Alexandrina Council, total adult, and Ae. camptorhynchus female adult mosquitoes caught in the 2016-2017 season.

Chart 11.3. Alexandrina Council, total and secondary species of adult mosquitoes caught in the 2016-2017 season.

152 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Adult Data.

Chart 11.4. Alexandrina Council, Average mosquito catch for the 2016-2017 season compared to the historic mean for the previous 5 years within Alexandrina Council Area.

153 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Adult Data.

Table 11.1. Totals for the five traps in Alexandrina Council Area.

Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 17/12/16 12/01/17 7/02/17 2/03/17 27/03/17 25/04/17 Season Total Ae. alboannulatus 0 0 0 1 0 0 0 0 0 0 0 1 Ae. camptorhynchus 35 169 404 578 97 27 1852.4 129 415 4 20 3730.4 Ae. notoscriptus 1 0 0 5 1 1 8 0 0 10 4 30 An. annulipes 0 0 4 2 0 10 17.4 0 1 0 1 34.4 Cq. linealis 0 0 0 1 1 0 0 10 85 5 0 117.5 Cx. annulirostris 0 0 0 0 0 1 0 1 10 0 0 12 Cx. australicus 0 0 1 5 2 1 0 0 0 0 3 12 Cx. globocoxitus 0 3 5 13 6 7 17.4 9 9 1 0 70.4 Cx. molestus 5 0 3 6 15 12 25.3 3 31 21 21 142.3 Cx. quinquefasciatus 0 0 4 0 1 7 1 28 6 3 0 50 Unidentifiable 0 0 0 0 0 0 0 0 2 0 0 2 Male 0 0 1 0 1 0 13 0 3 0 0 18 no captures 2 0 0 1 0 0 0 1 1 0 1 Trap failure 1 1 0 0 0 1 0 1 0 0 0 Total Adults 41 172 421 611 123 66 1937 180 559 44 49 4203 n=4 n=4 n=5 n=5 n=5 n=4 n=5 n=4 n=5 n=5 n=5 Total (n=51)

154 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Adult Data.

Table 11.2. Average Catch for the five traps in Alexandrina Council Area.

Species 27/08/16 20/09/16 15/10/16 7/11/16 1/12/16 17/12/16 12/01/17 7/02/17 2/03/17 27/03/17 25/04/17 Ae. alboannulatus 0 0 0 0.2 0 0 0 0 0 0 0 SE 0 0 0 0.2 0 0 0 0 0 0 0 Ae. camptorhynchus 8.75 33.8 80.8 115.6 19.4 5.4 370.5 25.8 83 0.8 4 SE 8.087 18.702 46.563 78.791 14.969 4.918 215.5 19.56 63.906 0.49 2.966 Ae. notoscriptus 0.25 0 0 1 0.2 0.2 1.6 0 0 2 0.8 SE 0.25 0 0 1 0.2 0.224 1.6 0 0 1.049 0.224 An. annulipes 0 0 0.8 0.4 0 2 3.5 0 0.2 0 0.2 SE 0 0 0.583 0.245 0 2.236 2.2 0 0.2 0 0.224 Cq. linealis 0 0 0.8 0 0.2 1.4 0.2 5.6 1.2 0.6 0 SE 0 0 0.374 0 0.2 1.565 0.2 2.852 0.583 0.6 0 Cx. annulirostris 0 0 0 0.2 0.2 0 3.1 2 17 1 0 SE 0 0 0 0.2 0.2 0 2.85 2.236 16.019 0.775 0 Cx. australicus 0 0 0 0 0 0.2 0 0.2 2 0 0 SE 0 0 0 0 0 0.224 0 0.224 2 0 0 Cx. cylindricus 0 0 0.2 1 0.4 0.2 0 0 0 0 0.6 SE 0 0 0.2 0.447 0.4 0.224 0 0 0 0 0 Cx. molestus 1.25 0.6 1 2.6 1.2 1.4 3.5 1.8 1.8 0.2 0 SE 0.75 0.428 0.548 2.135 0.735 1.565 1.1 0.563 1.356 0.2 0 Cx. orbostiensis 0 0 0.6 1.2 3 2.4 5 0.6 6.2 4.2 4.2 SE 0 0 0.6 1.2 2 1.826 3.3 0.671 5.463 3.955 0.847 Unidentifiable 0 0 0 0 0 0 0 0 0.4 0 0 SE 0 0 0 0 0 0 0 0 0.4 0 0 Male 0 0 0.2 0 0.2 0 2.6 0 0.6 0 0 SE 0 0 0.224 0 0.2 0 2.6 0 0.6 0 0 no captures 2 0 0 1 0 0 0 1 1 0 1 Trap failures 1 1 0 0 0 1 0 1 0 0 0 Total Adults 10.25 34.4 84.2 122.2 24.6 13.2 387.4 36 111.8 8.8 9.8 SE 7.653 18.316 46.804 79.41 14.002 10.155 219 24.416 66.678 4.375 3.905 n=4 n=4 n=5 n=5 n=5 n=4 n=5 n=4 n=5 n=5 n=5

155 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council.

Mosquito Larval Dipping and Treatment: Alexandrina Council.

Table 11.3. Results of Larval Dipping within Alexandrina Council.

australicus

globocoxitus

camptorhynchus

Cx.

Site Condition Site Cx.

Larvae present Larvae Ae. alboannulatus Ae.

Site Trip Date Ae. Density A1L5 1 11/8/2016 Full Yes * High A1L6 1 11/8/2016 Full Yes * Low A3L2 Other 11/8/2016 Full Yes * High A4L4 Other 11/8/2016 * Medium A3L4 2 20/9/2016 Full No A4L3 2 20/9/2016 Full No A3L3 3 14/10/2016 Full Yes * * Medium A3L4 3 14/10/2016 Full Yes * Medium A3L5 3 14/10/2016 Full Yes * Medium A3L6 3 14/10/2016 Full Yes * Low A2L3 5 30/11/2016 Full No A1L8 11 22/4/2017 Full No

Alexandrina Council larvicide treatments. This was the sixth year that Alexandrina Council joined the River Murray Mosquito surveillance program. Many potential larvae sites were investigated and those active sites containing were logged and some preventative treatment was undertaken. The area around A5, Port Elliot is thought to support at least one Cx. molestus larvae site, to alleviate this issue the area nearby drains were regularly treated with S-Methoprene briquettes. This treatment program seems to be effective on the population of Cx. molestus at this location, however, investigations and the treatment program will continue in future years. The larvae site at Tookarama Reserve (A3L2) adjacent Lindsay Parade was monitored and treated as required. This location was treated and will be investigated early each season along with saltmarsh further along Byrnes Road (A3L3 & A3L4). In addition to these sites a saltmarsh along Beach Rd, this was an extensive site found to contain the cool weather species Ae. camptorhynchus and suitable for implementing permanent briquette stations. The roadside verge near Milang (A1L5) was extensively treated in early August 2016 in a preseason application along with a drain near the new housing development at Milang (A1L6). These sites were then treated at the end of the season as a prophylaxis against winter larvae. Larvae sites were monitored within the council over the season and treated as required. In the council larvae, sites were discovered over time with only active larvae sites being recorded.

156 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. Larvae Data. Table 11.4. Larvicide application in Alexandrina Council during the 2016-17 season.

Site Date Product Quantity A1L5 11/8/2016 Briquettes 44 A1L6 11/8/2016 Briquettes 14 A1L7 11/8/2016 Briquettes 5 A1L8 11/8/2016 Briquettes 8 A3L2 11/8/2016 Briquettes 3 A4L4 11/8/2016 Briquettes 28 A5L4 11/8/2016 Briquettes 1 A5L5 11/8/2016 Briquettes 1 A5L6 11/8/2016 Briquettes 1 A5L7 11/8/2016 Briquettes 1 A5L11 11/8/2016 Briquettes 1 A5L12 11/8/2016 Briquettes 1 A5L13 11/8/2016 Briquettes 1 A5L14 11/8/2016 Briquettes 1 A3L3 14/10/2016 Briquettes 2 A3L4 14/10/2016 Briquettes 40 A5L1 14/10/2016 Briquettes 3 A2L3 30/11/2016 Briquettes 4 A5L4 30/11/2016 Briquettes 3 A5L5 30/11/2016 Briquettes 1 A5L6 30/11/2016 Briquettes 1 A5L7 30/11/2016 Briquettes 1 A5L8 30/11/2016 Briquettes 3 A5L9 30/11/2016 Briquettes 1 A5L10 30/11/2016 Briquettes 1 A5L11 30/11/2016 Briquettes 1 A5L12 30/11/2016 Briquettes 1 A5L13 30/11/2016 Briquettes 1 A5L14 30/11/2016 Briquettes 1 A5L4 7/02/2017 Briquettes 3 A5L5 7/02/2017 Briquettes 1 A5L6 7/02/2017 Briquettes 1 A5L7 7/02/2017 Briquettes 1 A5L8 7/02/2017 Briquettes 3 A5L9 7/02/2017 Briquettes 1 A5L10 7/02/2017 Briquettes 1 A5L11 7/02/2017 Briquettes 1 A5L12 7/02/2017 Briquettes 1 A5L13 7/02/2017 Briquettes 1 A5L14 7/02/2017 Briquettes 1 A1L6 22/4/2017 Briquettes 14 A1L5 22/4/2017 Briquettes 15 A1L8 22/4/2017 Briquettes 7 A3L2 22/4/2017 Briquettes 8 A4L4 22/4/2017 Briquettes 51 A5L4 22/4/2017 Briquettes 3 A5L5 22/4/2017 Briquettes 1 A5L6 22/4/2017 Briquettes 1 A5L7 22/4/2017 Briquettes 1 A5L8 22/4/2017 Briquettes 2 A5L11 22/4/2017 Briquettes 1 A5L12 22/4/2017 Briquettes 1 A5L13 22/4/2017 Briquettes 1 A5L14 22/4/2017 Briquettes 1

157 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Larvae Data. Discussion of Alexandrina Council results.

Adult mosquitoes. A total of 4, 203 (n=51) mosquitoes were trapped in the Alexandrina Council Area during the 2016/17 season. This is the sixth year that mosquito numbers have been monitored within Alexandrina Council; therefore, mosquito catches will be compared to historic patterns and seasonal catches from Coorong and Rural City of Murray Bridge Councils (Chart 10.2 & 9.2 respectively). Compared with the previous surveillance seasons, collections during the 2016-17 season were the second highest following the previous season. This is a little misleading as the total number of mosquitoes only slightly exceed the long-term mean (3, 870 adjusted for n=51) and the median catch of 3,780 (adjusted for n=55). In order to compare like figures the adjusted for n=55 the overall numbers were around a forty-five percent of the adult trap totals within Mid-Murray Council (10, 497), Murray Bridge (9, 578) and a third of the collections from Coorong Council (12, 890) see Table 12.1. However, the seasonal distribution of the early season mosquito catches broadly reflected the seasonal pattern in The Rural City of Murray and to a lesser extent the Coorong Council. Collections within Alexandrina Council exceeded the long-term means in November around a similar time as higher than average Collections were made in Murray Bridge and Coorong councils. However, catch numbers did not exceed the long term means by the same degree as in the other councils. In the following month mosquito numbers then declined to a fraction of the historic levels. Numbers then increased with high numbers of mosquitoes in collections from January particularly from Milang and Clayton Bay. Collections then rapidly declined but remained above long-term trends until April 2017 (Chart 11.4). During early March mosquito collections again increased with a small peak in the numbers of adult mosquitoes trapped around the township of Clayton where around half the mosquitoes caught were Cq. linealis (Table 11.1) the emergence of this species was later than normal seasons and could be related to the warmer than average temperatures during that month. The trap site at Port Elliot has in previous season been known for high catches of the problem mosquito Cx. molestus, this species was by and large restricted to this site and was still the second most abundant species identified from trap sites located within the council this season. During the current season, the most abundant overall catch was from Clayton (A2), with 2,135 (n=11) individuals recorded or 51.3% of all mosquitoes caught this season. This was followed by Milang (A1) with 1, 692 individuals (40.6% of the total catch for the council), and the remaining sites all had similar numbers of mosquitoes ranging from 95 to 131 individuals.

158 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Discussion.

Some mosquito species of note include;

Ae. camptorhynchus (3, 730, 88.8% of the total council catch) was the most common in the council area with most individuals being caught at Clayton (A2) and Milang (A1) with 1, 952.4 (n=11) and 1, 606 (n=10) individuals being identified (52.5%, and 43.2% respectively of all individuals of this species). The next highest catches were at Goolwa North (A3) and Goolwa (A4) both locations had similar numbers of Ae. camptorhynchus caught. Port Elliot only recorded comparatively few individuals Port Elliot (A5) with only 7 individuals or 0.2% of the total catch of the total catch for this species (Chart 11.2). Following the wetter than average winter months of September and July (Chart 11.1), several pools persisted into the early spring providing habitat for this species to overwinter as larvae. Increased control effort for Ae. camptorhynchus was undertaken this season, particularly around the town of Milang, with roadside verges and pond for collecting stormwater runoff. This location along with Clayton has some complicating factors affecting the efficacy of control. While some larvae sites have been identified on council land such as roadside verges, adjacent these sites are potentially more expensive larvae sites located on private land. Cx. molestus (142.3, 3.4% of the total catch) was the second most abundant species caught in Alexandrina Council with the majority of individuals being caught at the Port Elliot trap site (A5) 95 or 72.5% of the total catch for this species. The majority of the remaining catch 13 individuals or 10.4% came from Goolwa (A4) and the remainder from the remaining sites. This species was distributed sporadically across the season with the highest catches recorded towards the end of the season in March 2017 (Chart 11.3). Cq. linealis (117, or 2.8 % of total catch) was the third most abundant species within the local council area. As with previous seasons, this species was almost exclusively caught at Clayton (A2, 94.9% of the total species catch) and predominately in March (Chart 11.3, and Appendix 8). Cq. linealis is hard to manage as larvae sites are difficult to identify. The larvae of this species have a modified syphon that can pierce the roots of aquatic plants and that is how it obtains their oxygen. Therefore, dipping for larvae is almost impossible and control of larvae sites is invariably done by trial and error. Suspected larvae sites of this species are targeted on a regular basis. Cx. globocoxitus and Cx. quinquefasciatus (70.4 and 50, 1.7% and 1.2% of the total catch) these species were the fourth and fifth most abundant species caught in Alexandrina Council and even combined made up only a small component of the mosquito fauna. These species were distributed across the season at all trap sites but Cx. globocoxitus was found with more regularity at Milang with 64.8% of all individuals within the council caught at this site (Chart 11.3 and Appendix 8).

159 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Discussion. Cx. quinquefasciatus was more evenly distributed although it was more common at Clayton where 38% of all individuals of this species were captured. Ae. notoscriptus (22, or ≈0.5% of the total catch) was caught at the beginning and end of the season but was most abundant in March 2017 (Table 11.1). Ae. notoscriptus was unevenly distributed across the council with the majority of individuals or 77% of these species being trapped at Port Elliot. This is a container breeding mosquito that only flies short distances and was caught at all sites. Moderate catches of this species may represent a large problem site nearby as this species tends to be trap shy and because of discomfort due to its biting habits. Cx. annulirostris (12, 0.3% of the total catch) Overall the catch through the 2016-17 season was negligible with only 12 individuals identified. This species was caught on three occasions from December through to March 2017 it is important to mention as Cx. annulirostris as it is considered to be the most important vector of arboviral disease in mainland Australia.

160 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. - Discussion.

Table 11.5. Summary of monitoring season, Alexandrina Council.

FEATURE 2011/ 2012 2012/ 2013 2013/ 2014 2014/ 2015 2015/ 2016 2016/2017

Rainfall Events High falls in March /December Average winter/ dry season wet winter and February Wet early winter/ January High summer (Jan/Feb) September High in October, January pulse, River Levels Variable in late 2012 Variable in late 2013 raised downstream of locks in spring Lower lakes high over spring Unregulated flow late 2016 flood in April. Total female Mosquitoes 2, 030 (n=51) 4, 034 (n=52) 3, 034 (n=52) 2, 373 (n=54) 7, 736 (n=51) 4, 203 (n=51) Mosquito Peak November September September October/ December September/December Nov /Dec Dominant Species Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus Ae. camptorhynchus 22 (RRV, 21 probables, 4 Reported arbovirus infections 5 (RRV), 3 (BFV) 2 (RRV), 2 (BFV) 1 (RRV) 1 (RRV) 4 (RRV) confirmed)

161 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. COMMENTS.

Alexandrina Council joined the River Murray Mosquito Surveillance Program in the 2011- 12 season making this the sixth-year surveillance has been conducted in this council. The wetter than average July and September of 2016 enough to provide persistent pools suitable for the spring mosquito species Ae. camptorhynchus. These pools can be widespread and often occur on private land, the low-lying landscape on the margins of the lower lakes are ideal for this species. A preseason assessment of these pools was undertaken in mid-August 2016 and a number of the lakeside pools were found to contain larvae and were treated with S-Methoprene Briquettes. Monitoring continued over the season and treatments applied when required (Table 11.4). Further complications occurred with an unregulated flow event resulting in fluctuations in the level of the lower lakes (Chart 4.3). However, the impact of this variation in lake level seems to have been more pronounced on the eastern side of the lake in The Coorong District Council (Chart 10.7) with minimal impact on most locations with Alexandrina Council. The overall only 4, 203 (n=51) mosquitos were trapped over the 2016-17 season in Alexandrina Council, this was collections were the second highest on record and exceeded the historic mean and median for the council. This contrasts with the previous season which was the highest on record, with 7,736 (n=51) mosquitoes caught greater than any other river council over the 2015-16 season. Elevated mosquito numbers over in spring is common in the lower River Murray councils and historically a common feature in the upper river councils The increase in collections in January and into March seems restricted to be a result of conditions around Lake Alexandrina with increased collections coming from both Milang (A1) and Clayton Bay (A2). The increase in collections could be affected by the wind pushing water onto the lake shore and activating larvae sites. Over the 2016-17 season, the highest collections were made in early January 2017, with 46% of all mosquitoes trapped this season (1,937, n=5) caught at this time. Historically, Ae. camptorhynchus is caught throughout the season in the southern councils under favourable conditions. For example, 39% and 21% of all adult females caught in Coorong and Alexandrina councils in January have been Ae. camptorhynchus. However, historically collections at this time of the year are modest with averages of 14 individuals per trap night. To appear in the numbers recorded this season is rare (when considering data from Coorong Council) this is similar to the previous season where high numbers of Ae. camptorhynchus were recorded in December. In January, the burden of high mosquito numbers was not evenly shared across the council with 95% of all the mosquitoes caught at Milang and Clayton Bay. This accounted for nearly 46% of all the adult female mosquitoes trapped this season. The data collected this season demonstrates a point made in previously; that is while our records indicate mosquito numbers are at a certain

162 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. – Comments. level, this is only an indicator and variation in mosquito numbers at different locations bordering the lower lakes is to be expected. Although overall mosquito numbers were much lower than the previous seasons, the record high numbers of 2015-16 were confined to December and seemed to be related to an increase in the level of the lower lakes that peaked in late November 2015. This is interesting as the lower lakes peaked a month later in 2016-17 dropping at the end of December and into January (Chart 4.3). The extent surface water on private land surrounding the lower lakes provided extensive Ae. camptorhynchus larvae habitat with many sites. The control of these larval sites is beyond the scope of this program which focuses human health, control of recurrent problem larva sites and spot control. The identification and treatment of larvae sites is an ongoing process and as sites are identified management strategies are employed to minimise the effect on the residents and the wider community. Over the previous three seasons, the mosquito community sampled at the town of Port Elliot has been dominated by Cx. molestus. Following the first season when this potential problem became apparent an investigation of a potential source was conducted with several potential larvae sites identified. These sites have been treated periodically in order to alleviate the impact of Cx. molestus. This control program appears to have has an effect on the number of Cx. molestus identified from the Port Elliot trap site remaining low this season at 95 individuals (n =10). In the Alexandrina Council, 22 notifications of RRV were reported (21 probable and 1 confirmed), with the highest number with an estimated date of onset in February 2017.

163 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 11. Results: Alexandrina Council. LOCAL RECOMMENDATIONS.

The ongoing investigation into potential sources of Cx. molestus around the Port Elliot site A5 including drains and possible septic tanks should be continued and opportunities to expand this treatment program be investigated. Scheduling of a treatment program should be updated prior to the 2017-18 season, and to include problematic sites particularly around population centres. These sites are both known larvae sites of the early in the season mosquito Ae. camptorhynchus and will be targeted for early (possibly preseason) treatment with S-Methoprene briquettes due to their longevity. Establish permanent S-Methoprene stations at the larvae site at the end of Beach Road (A4L4) during winter 2015 and other known problem larva sites within the council, particularly for sites that are active annually. This may require some community consultation as a local revegetation group is active at the Beach Road site. Investigation of potential Ae. camptorhynchus larvae sites should be continued across the council in particular around Clayton, Milang and Goolwa North.

164 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17.

12. GENERAL DISCUSSION.

Mosquito monitoring, arboviral disease and climate.

Because we have retained the same methods and sample sites it is possible to make comparisons between each season since 1999/00. The overview of the overall number of mosquitoes caught in each council during each season is summarised in Table 12.1, while, Table 12.2 presents a summary of the important species mosquito abundances along the River Murray in SA over the eighteen seasons that this work has been conducted. Table 12.2 also contains a summary of the arbovirus cases reported within each council area. This presents an opportunity to scrutinise patterns over the seventeen seasons monitored so far. At present the three species of particular interest from a disease point of view are Cx. annulirostris, Cq. linealis and Ae. camptorhynchus. A brief description of these and other mosquito species relevant to environmental health has been supplied in Appendix 17. Adjusting for trap failures and the inclusion of Alexandrina Council numerically the 2016-17 season is most similar to the 2005/06 season which recorded the most similar overall number mosquito collections and also similar mosquito numbers at most councils. However, the composition of the collections that season differed with Ae. camptorhynchus dominating collections across the Riverland. In the upper river councils, the conditions of the 2010/2011 season have had an impact on the mosquito community for several years. The prolonged high river, particularly in the three upper river councils and the northern part of the Mid-Murray Council, coincided with a dramatic decline in the well-established populations of Ae. camptorhynchus in these areas. This is thought to be more than a coincidence and several explanations can be proposed including; • egg predation, • sequential hatching resulting in close to total hatching, • prolonged submergence drowning eggs remaining in diapause. This season the mosquito community reflected the pre-flood composition, with the return of spring cohorts of Ae. camptorhynchus across the upper River Murray. Although the unregulated flow event may have inundated some near river larvae sites reducing recruitment at these sites. At lease in Renmark Paringa Council a number of known Ae. camptorhynchus that were not exposed to fish predation were targeted with control measures. This seemed to have an impact on the collections of Ae. camptorhynchus adult’s females captured in this council compared to the adjacent Berri Barmera Council. Unfortunately, larvae sites around Martins Bend are less accessible and may benefit from targeted larvae control stations.

165 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 12. General Discussion.

The higher numbers of Ae. camptorhynchus adult’s females identified from CO2 baited EVS traps from the middle river, Coorong and Alexandrina councils resulted in this species comprising over 80% of all the mosquitoes caught this season across the lower river councils but only 10.8% of collections from the upper River Murray Councils (Table 12.1). Ae. camptorhynchus adult’s females were generally caught in later than the previous season, although this varied between regions. Adjacent the lower lakes Ae. camptorhynchus was collected in extraordinary during January 2017, probably in response to the unregulated flow event that had peaked in early January 2017. In the upper river Council of Berri Barmera collections of this species were strong late into the season with an average of 135 individuals per trap night as late as December 2017. The mid-season increase in mosquito numbers was driven by a number of different factors ranging from the high numbers of Ae. camptorhynchus trapped at some sites during December and January particularly in the south. Other factors include ideal conditions for An. annulipes and Cx. annulirostris in some regions of the River Murray. The number of adult females Cx. annulirostris identified across all council during the 2016- 17 season numbered 4, 981 (n=353), this was over 18 times the previous season's collections 270 (n=353, 2015-16) see Table 12.2. Cx. annulirostris is an important vector species across inland Australia it is common in warm weather following heavy rain or flood. Fortunately, the large rainfall event in September 2016 did not result in conditions suitable for a significant increase in adults of this species. The cooler conditions experienced following the high rainfall earlier in the season would have inhibited Cx. annulirostris larvae development [8]. The high precipitation in September, resulting in many pools that persisted with follow up rains. With suitable habitat for Cx. annulirostris larvae across the upper river that were constrained by the cooler conditions, The Mosquito and Public Health Research Group assessed many known larvae sites and implemented preventative control measures at many sites prior to temperatures increasing. The combined populations of the two important vector species Cx. annulirostris and Ae. camptorhynchus constituted around 62% of the total mosquito population sampled along the River Murray during the 2016/17 season. Historically, seasons with a higher proportion of these two species typically recorded high numbers of Ross River Virus notifications. The lower proportion of these species and elevated arboviral notifications could in part be due to changes in reporting or other unrecognised effects. Formal analysis of arbovirus incidence and mosquito abundance is continuing in collaboration between UniSA and the SA Department of Health. However, some general points can be made with respect to the above tables: ▪ Higher arbovirus prevalence coincides with high mosquito abundance. However, the relationship is not a simple one;

166 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 12. General Discussion. ▪ Historically some seasons with significant arbovirus prevalence, 1999-00, 2000-01 and 2005-06 featured high numbers of Ae. camptorhynchus. It is likely that Ae. camptorhynchus is implicated in arbovirus transmission along the River Murray in SA (Table 12.2). During the 2016-17 season The Healthy Environment, Healthy People Research Group continued the trail of the new passive mosquito trap utilising a new method for screening mosquitoes for arboviruses (FTA cards). This was done in co-operation with colleague’s interstate were the system was also being trailed and with technical assistance from Giles Cortis. The passive trap systems were deployed adjacent sentinel chicken flocks located in Qualco, Murray Bridge and Meningie. Two other passive traps were sighted at the Renmark Local Council Offices and the Loxton Early Settler Village. During the current season, no positive results were obtained from this system and technical difficulties resulted in trials at the Qualco being abandoned. The significance of this information and the usefulness of these methods are being considered and more widespread trials in future years may result. This season we continued fitting modified EVS traps with FTA cards to monitor arboviruses along the River Murray. This program is now built into the regular surveillance program and adds value to the mosquito monitoring program with two of the five traps within each council fitted with FTA cards each collection trip. The FTA card technology is promising in

South Australian with detections of arbovirus in modified EVS CO2 baited light trap during 2016- 17. Following the detections in early December (trap collected on December 1st), the number of FTA cards set out was increased to include 100% of all EVS traps. The number set was then decreased as mosquito collections declined. The advantages of this type of trap over conventional arbovirus monitoring (e.g. Sentinel Chicken flocks, live capture of mosquitoes) are the reliability and apparent sensitivity. While the downside is the inability to identify actual vector species (traps may contain multiple species). The pattern of precipitation was broadly similar along the length of the River Murray with rainfall in September 2016 well above long-term means along the River Murray. While precipitation was also well above average in December and January in the lower and middle sections of the River. Overall for the 12 months to May 2017 Rainfall was above average along the length of the river. The River Murray itself received an unregulated flow event spanning the second half of 2016, with river levels abruptly dropping progressively along the river in the new year (Chart 4.2). This flow event also resulted in an increase in the height of the lower lakes spanning most of January 2017. This variation in lake level in conjunction with increased rainfall may have produced rewetting of potential larvae sites and provided opportunities for sequential hatching Ae. camptorhynchus around the lower lakes.

167 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 12. General Discussion. The season was typified by cooler spring days than historic means at all weather stations from spring, followed by average summer temperatures in around Renmark and warmer conditions elsewhere. The Daily Maximum air temperatures were consistently warmer than long-term means at all locations in March 2016. Chart 12.1 illustrates fluctuations in the Southern Oscillation Index over the past two years. When the values are negative, weather patterns are trending towards the El Niño phenomenon, bringing dry, cool conditions to south-eastern Australia. When the values are positive the La Niña pattern brings wet and warm conditions associated with mosquito problems and arboviral disease. Around the middle of 2016, the conditions changed, with the 30-day moving average moving abruptly positive and remaining positive over most of the 2016-17 season. The Bureau of Meteorology modelling indicates a 50% likelihood of a La Niño forming during 2017. The Indian Ocean Dipole (IOD) is currently neutral, with two-thirds of models suggesting a positive IOD may develop over winter. Such conditions are associated with drier than average conditions over the last half of the year.

Chart 12.1. Southern Oscillation Index with 30 days moving Average weighted mean since January 2015.

168 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 12. General Discussion.

Table 12.1. Summary of total adult mosquito catch for all seasons.

COUNCIL 1999/00 2000/01 2001/02 2002/03 2003/04 2004/05 2005/06 2006/07 2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14 2014/15 2015/16 2016/17 AREA Renmark Paringa 3997 6969 1344 1228 1626 2668 13060 862 782 2125 914 16254 1599 1445 899 1323 1006 7800 n=44 n=54 n=55 n=54 n=54 n=54 n=52 n=52 n=53 n=53 n=51 n=54 n=51 n=52 n=53 n=53 n=51 n=51 Berri Barmera 6572 8350 622 600 1885 1609 13053 1658 598 1228 1329 24432 2439 1994 682 856 314 12339 n=43 n=54 n=51 n=50 n=55 n=55 n=51 n=54 n=51 n=49 n=54 n=53 n=50 n=51 n=54 n=51 n=51 n=49 Loxton Waikerie 6588 4748 701 379 2011 567 2736 1287 401 1069 964 9536 727 806 388 1917 313 4371 n=45 n=54 n=54 n=49 n=51 n=53 n=51 n=52 n=53 n=52 n=52 n=49 n=48 n=50 n=53 n=52 n=51 n=53 Mid-Murray 1763 1873 594 442 1270 1387 2188 475 334 490 1120 9431 1329 1333 1556 1408 1561 10115.7 n=44 n=54 n=54 n=52 n=55 n=54 n=52 n=51 n=54 n=52 n=51 n=53 n=49 n=50 n=49 n=53 n=49 n=53 Murray Bridge 2810 1930 2917 1463 3171 3406 9502 1553 768 1147 2255 10896 2223 3612 9598 3444 6127 9229.8 n=43 n=53 n=53 n=53 n=53 n=53 n=54 n=51 n=54 n=53 n=54 n=54 n=54 n=53 n=54 n=47 n=49 n=53 Coorong 1964 4632 5024 1636 5987 1541 12918 3287 1145 398 993 8302 5438 16423 29919 3223 2443 11718.5 n=41 n=55 n=54 n=51 n=52 n=54 n=53 n=50 n=53 n=52 n=51 n=54 n=48 n=49 n=54 n=48 n=51 n=50 Alexandrina 2030 4034 3034 2373 7735.88 4203 n=51 n=51 n=52 n=54 n=51 n=51 GRAND 23694 28502 11202 5748 15950 11178 53457 9122 4028 6457 7575 78851 15785 29647 46076 14544 19499.88 59777 TOTAL n=260 n=324 n=321 n=309 n=320 n=323 n=313 n=310 n=318 n=311 n=313 n=317 n=351 n=356 n=369 n=356 n=353 n=353

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Table 12.2. Summary of Mosquito species and arbovirus cases across councils, from 1999-2016.

1999 -2000 2000 - 2001 2001 - 2002 2002 – 2003 2003 – 2004

COUNCIL Cx. an Ae cam Cq. lin An an RRv Cx. an Ae cam Cq. lin An an RRv Cx. an Ae cam Cq. lin An an RRv Cx. an Ae cam Cq. lin An an RRv Cx. an Ae cam Cq. lin An an RRv Renmark Paringa 1493 1283 134 229 35 1515 3307 731 141 2 95 208 493 267 2 34 35 531 127 2 103 342 783 174 3 Berri Barmera 3482 2262 1 302 25 1827 4778 6 333 5 102 137 19 70 2 10 57 36 10 0 350 792 31 53 1 Loxton Waikerie 3575 1873 053 503 40 1264 1656 235 921 5 54 343 128 37 6 5 151 13 39 0 445 1169 12 92 1 Mid-Murray 100 1054 3 38 11 491 701 1 313 26 7 386 2 7 3 5 271 0 23 0 639 149 0 183 2 Murray Bridge 111 2029 1 52 5 33 1147 23 125 6 0 2545 35 5 4 0 707 17 24 1 12 1463 28 48 2 Coorong 50 1194 9 34 1 173 2571 12 616 20 10 3268 18 94 1 0 770 2 4 0 11 3213 1 754 0 GRAND TOTALS 8811 9695 201 1158 117 5303 14160 1008 2449 64 268 6887 695 480 18 54 1991 599 227 3 1560 7128 855 1304 9

2004-2005 2005-2006 2006-2007 2007-2008

COUNCIL Cx. an Ae cam Cq. lin An an RRv BFv Cx. an Ae cam An an Cq. lin RRv BFv Cx. an Ae cam An an Cq. lin RRv BFv Cx. an Ae cam An an Cq. lin Cx. mol RRv BFv Renmark Paringa 318 1052 731 141 4 0 212 9768 876 1304 17 4 39 166 53 389 2 2 138 86 107 321 28 4 1 Berri Barmera 199 803 45 35 2 0 105 11567 225 472 17 1 48 651 13 317 0 2 69 226 44 26 138 7 2 Loxton Waikerie 60 223 20 49 2 0 22 1840 131 322 5 1 12 688 41 310 10 2 23 80 80 45 16 5 3 Mid-Murray 67 690 236 157 2 0 192 1451 59 3 6 2 2 140 14 0 1 1 73 16 14 2 113 2 2 Murray Bridge 21 2443 43 13 1 0 149 7350 166 43 7 7 38 776 30 17 6 15 16 336 8 0 82 10 8 Coorong 1 916 1 4 1 6 60 9996 313 9 43 22 3 2384 10 7 4 2 11 455 9 0 547 7 3 GRAND TOTALS 666 6127 1076 399 12 6 740 40772 1770 2153 95 37 142 4805 161 1040 23 24 330 1199 262 394 924 35 19

2008-2009 2009-2010 2010-2011

COUNCIL Cx. an Ae cam An an Cq. lin Cx. mol RRv BFv Cx. an Ae cam An an Cq. lin Cx. mol RRv BFv Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv MVE Renmark Paringa 46 1377 245 260 59 11 1 143 398 61 146 22 21 3 12,029 2,431 1,003 128 8 51 15 0 Berri Barmera 120 450 35 14 263 7 0 189 556 44 25 191 10 0 14,286 6,709 1,017 299 53 70 14 1 Loxton Waikerie 55 475 43 54 277 3 2 84 627 71 70 41 12 0 5,770 2,301 516 33 34 129 18 0 Mid-Murray 2 35 25 2 249 2 1 38 775 24 6 152 9 1 7,989 365 229 3 35 153 7 1 Murray Bridge 1 707 4 0 50 8 5 25 1249 23 28 57 8 1 3,597 4,251 562 0 646 49 6 0 Coorong 0 204 1 0 95 10 6 7 632 3 0 159 0 0 1,870 2,931 362 0 1,455 34 5 0 Total Adult Females 224 3248 353 330 993 41 15 486 4417 226 275 622 60 5 45,541 18, 988 3,685 463 2,231 486 65 2 Note, Numbers in brackets in arbovirus totals indicate an indeterminate Riverlands’ source of infection 170 | P a g e A survey of mosquitoes along the River Murray in South Australia 2016-17. 12. General Discussion.

Summary of Mosquito species and arbovirus cases across councils, from 1999-2016 (cont).

2011-2012 2012-2013 2013-2014

COUNCIL Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Renmark Paringa 471 12 323 67 1 8 3 446 18 459 223 3 9 3 128 43 226 361 10 2 Berri Barmera 770 2 126 116 6 6 5 915 9 347 29 8 3 4 137 10 56 8 37 7 Loxton Waikerie 214 12 125 0 13 18 6 188 23 250 1 7 17 8 42 27 29 3 15 5 3 Mid-Murray 518 231 97 4 12 6 4 131 483 113 1 35 5 0 34 1023 55 2 30 3 2 Murray Bridge 103 1277 59 30 278 9 2 118 2704 43 75 309 8 7 13 8302 27 211 658 2 3 Coorong 73 4678 217 4 151 3 2 48 15936 35 3 59 3 2 5 28672 98 8 692 4 2 Alexandrina 40 1054 44 36 72 5 3 17 3205 66 280 63 2 2 1 2429 4 156 197 1 GRAND TOTALS 2189 7266 991 257 533 55 26 1863 22378 1313 612 484 52 (5) 27 (1) 360 40506 495 749 1639 26 (2) 10

2014-2015 2015-2016 2016-2017 COUNCIL Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Cx. an Ae cam An an Cq. lin Cx. glob RRv BFv Renmark Paringa 123 682 110 168 10 6 0 90 276 294 131 18 2 0 551 351 3623 86 58 33 0 Berri Barmera 110 341 22 3 7 7 0 27 66 37 20 4 6 1 2805 1923 877 31 131 32 0 Loxton Waikerie 77 1587 29 17 67 1 0 38 108 45 9 23 1 0 540 375 1147 2 86 49 0 Mid-Murray 30 1092 148 1 19 3 0 104 1289 28 0 32 4 0 821 8004.7 776 14.5 63 37 0 Murray Bridge 29 2544 13 111 467 0 0 8 4703 58 220 955 1 1 147 7845.3 212.3 232 336 16 0 Coorong 0 2682 20 21 253 12 0 1 1940 15 71 194 7 0 117 9759.4 1265 34 285.1 25 1 Alexandrina 3 1663 8 381 33 1 0 2 7157 12 250 89 4 0 12 3730.4 35.4 117.5 70.4 22 0 GRAND TOTALS 372 10591 350 702 856 36 (6) 0 270 15539 489 701 1315 28 2 4993 31988.8 7935.7 517 1029.5 214 1

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Reports to Council Environmental Health Officers.

Two preseason meetings were held providing the opportunity to bring together EHOs from the Participating councils in the upper and lower sections of the River Murray Surveillance area. The face to face meeting allowed for more effective communication and co-operation between EHO’s. Regular bulletins were sent out to Environmental Health Officers (EHO’s) giving the most recent trap data and making comparisons with previous seasons. In addition, news items about trends in mosquito biology, and recent outbreaks of arboviral disease both nationally and internationally were related to Council EHO’s via the Facebook page (Mosquitoes of South Australia) and Healthy Environments, Healthy People Research Group website and blog. ‘Mosquito Intelligence Reports’ have been developed for distribution to stakeholders listing projected risk of arboviral infection and mosquito catch summary for the period.

Spot control of larval mosquitoes.

Larval habitats previously identified over the previous fifteen years were regularly monitored by larval dipping. Where these sites held larval mosquitoes or had potential to support a recruitment event, appropriate treatments were applied. A number of problem larvae sites were also pre- emptively treated with S-Methoprene briquettes; this allows for more efficient control of some larvae sites. Further to this, the search for new larval sites continued, with the addition of some new sites in some council areas. It should be remembered that the Healthy Environments, Healthy People Research Group is not engaged to conduct widespread control of larval mosquitoes. Rather, we scan areas we pass on our regular adult sampling trips for larval habitats and conduct spot control where necessary. In addition, potential sites are investigated using tools such as Google Earth and topographical maps. This arrangement came about when it was found that the delay between informing councils about problem sites and the application of control by council staff was not tolerable. Consequently, we were asked to conduct spot control immediately when sites are easily controlled.

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As in previous seasons, Healthy Environments, Healthy People Research Group has been in regular contact with the various EHOs. We know that they are busy individuals with a vast range of responsibilities. Consequently, they are contacted about specific problems and advise them on what action to take. This Healthy Environment, Healthy People Research Group provided data and comment to all the Councils along the River and the Department of Health keeping them informed of the numbers of mosquitoes and the composition of the catch at various sites along the River Murray and Lower Lakes. This season the Healthy Environments, Healthy People Research Group has continued producing the “South Australian Mosquito Intelligence Report” this report summarises data from RR Forecaster the Murray River Surveillance program and other projects conducted Healthy Environments, Healthy People Research Group. The SAMIR is distributed to all stakeholders including the Department of Health and partner Local Councils. Discussions with the Department of Health have raised the prospect of further contributions with regard to the department's mosquito monitoring and arboviral notification data. The Healthy Environments, Healthy People Research Group is also developing a website with various resources for EHO’s and the general public.

Community engagement.

During the 2016-17 season, Stephen participated in radio interviews to local Riverland ABC.

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13. GENERAL RECOMMENDATIONS.

Within each section of this report, we have made recommendations to local councils. Here follow a series of general recommendations: ▪ Obtain feedback on the Murray River Mosquito Program from the participating Council Environmental Health Officers. ▪ Continue the current sampling program; ▪ Set up a series of special projects to address particular issues within each council area (see recommendations for each council area); ▪ Encourage the NRM boards to provide for/undertake the investigation of the relationships between environmental releases/flow and populations of potential vector mosquito species in the Lower River Murray; ▪ Discussions have been underway to expand SAMIR to include more information from the Department of Health ▪ Continue to encourage the NRM boards to provide for/undertake mosquito surveillance of areas subject to environmental releases/flow and if necessary take responsibility for control of populations of potential vector mosquito of health importance; ▪ Investigate any relationship between raised lock levels for inducing environmental water flows and populations of vector mosquitoes; ▪ Continue and improve on the passive trap arboviral screening along the River Murray. ▪ Continue inclusion of FTA cards in routine EVS traps trailed previous seasons along the River Murray. Deploy FTA cards more effectively across the season with increased coverage in higher risk periods. ▪ Revise contingency plans for future epidemic seasons/flood events plans need to be implemented and revised on a regular basis.

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14. REFERENCES. 1. van den Hurk, A.F., et al., Vector competence of Australian mosquitoes for chikungunya virus. Vector-Borne and Zoonotic Diseases, 2010. 10(5): p. 489-495. 2. Williams, C.R., S.R. Fricker, and M.J. Kokkinn, Environmental and entomological factors determining Ross River virus activity in the River Murray Valley of South Australia. Australian and New Zealand Journal of Public Health, 2009. 33(3): p. 284-288. 3. R.C., R., Mosquitoes and Mosquito-borne Disease in South-eastern Australia. Dept. of Medical Entomology, Westmead Hospital and Dept. of Medicine, Sydney University: Sydney. 1993. 4. Dobrotworsky, N.V., The Mosquitoes of Victoria (Diptera, Culicidae). The mosquitoes of Victoria (Diptera, Culicidae). 1965. 5. Ritchie, S.A., et al., A simple non-powered passive trap for the collection of mosquitoes for arbovirus surveillance. Journal of medical entomology, 2013. 50(1): p. 185-194. 6. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2014-15. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council. 2015, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia. 7. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2015-16. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council. 2016, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia. 8. Lee, D.J., et al., The Culicidae of the Australasian region. Volume 7, Nomenclature, synonymy, literature, distribution, biology and relation to disease Genus Culex Subgenera Acallyntrum, Culex. Entomology monograph ; no. 2. 1989, Canberra: Australian Govt. Publishing Service. 9. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2010-11. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge and The Coorong District Council. 2011, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia. 10. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2013-14. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council. 2014, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia. 11. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2012-13. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council. 2013, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia. 12. Fricker, S.R. and C.R. Williams, A survey of mosquitoes along the Murray River in South Australia 2011-12. A REPORT PREPARED FOR; Renmark Paringa Council, Berri Barmera Council, The District Council of Loxton Waikerie, The Mid-Murray Council, The Rural City of Murray Bridge, The Coorong District Council and Alexandrina Council. 2012, Healthy Environments, Healthy People Research Group, School of Pharmacy & Medical Sciences, The University of South Australia.: Adelaide, South Australia, Australia.

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15. ONLINE RESOURCES.

The Bureau of Meteorology http://www.bom.gov.au/index.shtml DWLB South Australian Surface Water Archive http://e-nrims.dwlbc.sa.gov.au/swa/Default.aspx Southern Oscillation Index Archive http://www.bom.gov.au/climate/current/soi2.shtml Healthy environments, healthy people research group https://hehp.wordpress.com/

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APPENDIX 16 List of abbreviations

Abbreviations of Mosquito Genera

Genus name Abbreviation Aedes Ae. Anopheles An. Coquillettidia Cq. Culex Cx. Mansonia Ma. Tripteroides Tp.

Other Abbreviations AHD -Australian Height Datum BFV -Barmah Forest virus BoM -Bureau of Meteorology CHIKV -chikungunya Virus DWLBC -Department of Water, Land and Biodiversity Conservation, MDNRM -Board -South Australian Murray-Darling Basin Natural Resources Management Board. MVE -Murray Valley Encephalitis RRV -Ross River virus infection STRV -Stratford Virus-Flavivirus subtype of Kokobera virus (KOKV) in the Kokobera virus complex, related to MVE and Japanese Encephalitis. 14DMADMax -14-day moving average for the maximum temperatures. 14DMADMin -14-day moving average for the minimum temperatures.

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APPENDIX 17: An abridged guide to mosquito of medical importance in South Australia.

Aedes camptorhynchus Aedes notoscriptus

This species is typically a major pest in coastal This species is not currently considered a areas in parts of SA, and a known laboratory vector of major vector of arboviruses. However, Ae. notoscriptus is Ross River Virus and can carry MVE virus, along with a major vector of dog heartworm and a major nuisance dog heartworm and myxomatosis of rabbits. around homes in urban and rural areas. This species is The larvae are usually found in brackish to a container breeder utilising tree holes, old tyres, self- fresh ground pools associated with coastal swamps and watering pots, rainwater tanks etc. Ae. notoscriptus does bushland, but also is salinity affected areas inland. This not disperse far from larval sites and will seek refuge in species is the counterpart of Ae. vigilax along the coast cool shaded areas. This species usually bites around of Adelaide and can be found together in fewer saline dusk, attacking humans on the feet and hands. Having conditions where the species range overlaps. The larvae such a predictable biting behaviour assists in identifying are identified by a syphon with one pair of branched the species remotely. hair tufts above the pectin about mid-length. Head hair The adults of Ae. notoscriptus are readily 5 and 6 are branched, and a saddle covers half the dorsal identifiable; they are small and dark with a silver lyre of the anal segment with papillae generally very small. pattern on the scutum, a black proboscis with a silver Adults can be active throughout the year and band around the mid-point; a pleuron speckled with disperse widely from larval habitats; they can be vicious clumps of silver scales and black legs with basal white biters readily attacking humans and other animals bands. The larvae have a short syphon, and head hairs including birds, feeding during the day, at dusk and after 5 and 6 are single. The anal papillae are asymmetric with sunset. The adults are a medium sized darkish mosquito the upper somewhat longer than the lower; a distinctive with banded legs. The majority of the proboscis is feature of this species. extensively mottled, particularly on the underside. Wings are completely dark scaled. The abdominal tergites have pale basal bands which are often convex or triangular in the midline, with sternites pale scaled with median black patches.

Adult female Aedes camptorhynchus

Adult female Aedes notoscriptus

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Coquillettidia linealis Culex annulirostris

This medium sized brown species is found This species has a patchy distribution, being throughout Australia. In south-eastern Australia, it locally abundant close to suitable larval sites, and occasionally occurs in large numbers following rain increasing in abundance as the weather warms in late and flooding, particularly in warmer weather. It is an spring. Coquillettidia linealis can be a local pest around opportunistic feeder biting a variety of hosts including breeding sites. Although there are reports of biting humans, other mammals and birds, particularly at throughout the day it has been found to be active dawn and dusk but also throughout the night. This predominantly at sunset then through the night in SA species is considered to be one of the most significant (in a study near Paringa). Management of this species vectors of arboviruses in Australia. Adult is problematic as the larval habitat can be difficult to Cx. annulirostris are readily identified by having a identify. The reason for this is that the larvae undertake banded proboscis, and legs with basal pale bands. It gas exchange through plant tissue, attaching to the also has distinctive scale patterns on the abdomen roots of emergent vegetation and obtaining oxygen with a pale ventral surface with incomplete dark apical directly from the plant. This is a mechanism that has bands. The larvae of this species can be readily evolved to avoid predation and results in larvae being identified without visual aids by the presence of two difficult to collect. This species is known as a dark patches on the dorsal surface and a long syphon. competent vector of arboviruses, including Ross River virus.

Adults have a distinctive lateral pale stripe on the hind tibia, and apical dark bands extending medially on the ventral abdomen. The larvae can be difficult to find and quite distinctive with a syphon modified with plant-piercing valves.

Adult female Coquillettidia linealis Adult female Culex annulirostris

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The Culex pipiens group

There are four members of the Culex pipiens complex found in SA, a closely related group of species that can be difficult to distinguish visually as adults. These are Cx. quinquefasciatus, Cx. globocoxitus, Cx. molestus and Cx. australicus. The larvae of each species are difficult to identify to the untrained eye. Internationally, members of this species group are known vectors of arboviruses (e.g. West Nile virus) and lymphatic filariasis (Wuchereria bancroftii). However, these pathogens are currently not a problem in Australia. Larvae of both Cx. australicus and Cx. globocoxitus are preferentially found in clean, still water in swamps, channels and pools. Whilst Cx. australicus displays a preference for freshwater environments, the larvae of Cx. globocoxitus are commonly associated with brackish water. In contrast to these native species the larvae of both Cx. molestus and Cx. quinquefasciatus are most commonly associated with organic-rich, polluted water. Further, both Cx. molestus and Cx. quinquefasciatus display a strong preference for artificial breeding sites, including drains, rainwater tanks, discarded tyres and abandoned swimming pools.

Adult female Culex globocoxitus

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