ArticlelArtikel

THE SEASONAL ACTIVITY OF ADULT IXODID ON ANGORA GOATS IN THE SOUTH WESTERN ORANGE FREE STATE

L J FOURIE* and I G HOR4-K**

ewes on the farm kidded and their kids became the fourth group. During March ABSTRACT 1989 the young wethers were excluded Adult btodid ticks were collected at 2·weekly intervals for a period of23 from the study and the kids born during consecutive months from 15 to 20 Angora goats on a farm in the south the previous year were then considered as western Orange Free State. A total of 6 ixodid spedes were the young goat group. Angora ewes on recovered. p:unctatus was tbe most abundant and the farm kidded again during December prevalent tick, It was present from spring to late summer. Ixodes 1989, and the first observations on the se­ cond group of kids were made during rubicundus .'WUtbene~t most abUlldant tlck and was present mainly frOln March or April July with peak numbers present in April or January 1990. to Five belonging to each of the 3 May. The onset of this tick's activity appeared to be stimulated by low or 4 survey groups were examined for atmospheric temperatures. ticks at 2-weekly intervals from March 1988 to January 1990. Each body region Key words: Angora goats, ixodid ticks., seasonal activity was careij.tlly searched by parting the hair and visually inspecting the epidermis. All Fourie L.J.; Horak l.G. The seasonal activity of adult ixodid ticks the adult ixodid ticks found were col­ en Angora goa.ts in the south western Orange Free State. Journal lected, placed in labelled bottles, iden­ oJ the South African Veterinary Association (1991) 62 No. 3, 104~106 (En.) tified and counted using a stereoscopic t>epartment of Zoology and Entomology~ University of the Orange microscope. Burdens were expressed in :Free State, 9301 Bloemfontein, Republic of South Africa. terms of infestation density (numbers of .J ticks per kg host mass) and results

) presented in tabular and graphical form. 1

1 To test for significant differences between 0

2 sex ratios a Chi-squared test was used.

d INTRODUCTION Free State. The farm comprises an area Where reference is made to tick activity, e t Althougl1 and comprise the approximately 6 000 ha in extent and it is inferred that these ticks actively quest a d major portion of the livestock industry in topographically ~onsists of flat as well as for hosts either from the ground or from (

r the southern Orange Free State, about hilly ground. The vegetation in the area is vantage points on the vegetation and then e 1 h 60 000 Angora goats are also farmed in defined as False Upper Karoo • A fenced enter the parasitic phase of their life s i l this province. Some research on tick in­ camp on the farm, encompassing 190 ha cycles. b In order to quantify seasonal abun· u festation of Angora goats has been done in of vegetation typical of the region, was

P 7 8 the eastern Cape Province6 and the selected for this study. dance, the tick infestation densities of the e various groups of goats were pooled. Ex­ h mortality of Angora goats caused by' a The climate is semi-arid, with 69% Qf t paralysis-inducing tick occurring the annual rainfall occurring during the cept for 1. rubicundus and R. punctatus, y b the numbers of the other tick species were in the southern Orange Free State has summer months. Mild to severe droughts d 2• too low to determine seasonal tendencies. e been recorded The present paper \occur periodically. Air temperatures ex­ t

n describes the seasonal activity of adult ix­ hibit major circadian and seasonal fluc­ a RESULTS r odid ticks on Angora goats on a farm in tuations with absolute temperatures vary­ g the south western Orange Free State. ing between 39°C and -6,3°C. Total Total monthly rainfall and mean at­ e c Similar studies on sheep and cattle on this monthly rainfall during the study period mospheric temperatures are graphically n e farm have already been published3 5. was recorded at "Preezfontein" and mean illustrated in Fig. 1 & 2. c i l maximum and minimum temperatures The total numbers and relative abun­

r dance of adult ixodid ticks collected from e MATERIALS AND METHODS were obtained from a weather station at d The study was conducted on the farm Fauresmith. the goats are summarised in Table I. Ex' n u "Preezfontein", which is situated 10 km Four age and sex class categories of cept for Rhipicephalus evertsi evertsi and

y from the town of Fauresmith (29° 46'S; Angora goats were used, namely adult Rhipicephalus gertrudae, where the sample a

w 25° 19'E) in the south western Orange ewes, adult wethers, young wethers (7 sizes were too small, there were signifi· e t months old) and kids. Each group ini­ cant differences (p < 0,05) in the set a tially consisted of 10 animals. Because ratios of male to female ticks. With the G

t *Department of Zoology and Entomology, Univer· tick-induced paralysis and other causes exception of 1. rubicundus, more male e

n sity of the Orange Free State, 930 I Bloemfontein, resulted in mortality, the groups of young than female ticks were present on the i b Republic of South Africa goats and kids eventually contained be­ goats. a **Faculty of Veterinary Science, University of

S tween 5 and 10 animals each. The study The seasonal abundances of 1. rubicuT/­ Pretoria y on adult and young goats started during dus and R. punctatus are graphically il­ b Received: January 1991 Accepted: April 1991 March 1988. During October 1988, the lustrated in Fig. 3 & 4. d e \ c u 0038-2809 JI S.Afr.vet.Ass. (1991) 62(3):104-106 d 104 o r p e R Table 1: Adult ixodid ticks collected from Angora goats on the farm the long term, differentially affect the "Preezfontein" epidemiology of the toxicoses caused. Hyalomma truncatum was the most abundant of the 2 Hyalomma species col­ Numbers recovered lected. Most (> 65%) of these ticks were Tick Males Females Total Relative % goats collected during the summer months species abundance infested Ganuary - March). The relatively low number collected from goats in the pre­ Hyalomma sent study, suggests either that these marginatum animals are poor hosts of these ticks or rufipes 33 8 41 0,69 3,6 that Angora goats minimise contact with the ticks through behavioural patterns. Hyalomma Both H. marginatum rufipes and H. trun­ truncatum 45 27 72 1,21 4,7 catum seek hosts from the ground and not from the vegetation and this may affect Ixodes tick/host contact .., rubicundus 897 1155 2052 34,34 36,2 Although free-IJving, newly moulted adult 1. rubicundus are already present Rhipicephalus during December or January (summer), evertsi this tick is parasitic virtually only during evertsi 3 3 0,05 1,4 the winter months, and it is reasonable to ° assume that low temperatures stimulate Rhipicephalus the onset of tick activity. A comparison of gertrudae 16 10 26 0,44 0,4 mean minimum temperatures for 1988 and 1989 shows that those for the 3 Rhipicepha- months preceding tick activity Ganuary­ lus punctatus 2084 1698 3782 63,29 53,6 March) were lower during 1989 than dur­ ing the 1988 season. During March 1989

40

120

100 ) 1

1 W 0:: 0 :::J

2 I-

d ~20 e w t Il.. :::IE a W d I- ( Ii 40 )~ :i! r

e 10 h s

i 20 l IJ b u P o M A M J J A SON 0 J F M A M J J A SON 0 e 1S88 19119 h MONTH t y b Fig. 1: Total monthly rainfall on the farm "Preez­ Fig. 2: Mean monthly minimum and maximum d e fontein" from March 1988 to January 1990 t temperatures at Fauresmith for the period n March 1988 to December 1989 a r g e c n e

c DISCUSSION i l There are some differences in the relative truncatum on the sheep and 1. rubicundus minimum temperatures fell below 10°C r e abundance of adult ticks of the various on the cattle. These differences in relative on 6 occasions, compared to only once d n species infesting the goats and those re­ abundance are probably due either to host during March 1988. This may explain u covered from sheep and cattle examined preference of the ticks, to habitat why infestation occurred about one y a on the same farm in previous surveys. preference of the ticks or hosts, or to month earlier during 1989 than in 1988. w relative abundances of the 4 major behavioural differences ofthe hosts which The variation in the commencement of e ~he t tick species recovered from the 3 host a may affect tick-host contacts. According­ tick activity and peak activity periods bet­

G species on the farm, are summarised in ly, depending on the number and type of ween years is significant. In an earlier

t Table 2. e hosts frequenting a specific area, the survey on sheep L rubicundus became ac­ n i IiYalomma marginatum rufipes was numbers of ticks within this area may in­ tive on "Preezfontein" during April 1987 b propo ' a 1 rtlonately most abundant on cattle, crease because of the greater availability and reached a peak during May3. In both

S rub' ~n h lcundus on sheep and R,. punctatus of suitable hosts. Since H. truncatum, L surveys, tick burdens reached a peak y b Ita t e goats. H. marginatum rufipes was rubicundus and R. punctatus can all cause within 4 weeks after the commencement

d St abundant on the goats, Hyalomma tick toxicosis24, stocking densities may, in of the activity. e c u 0038-22 . d 809 Tydskr.S.Afr.vet. Ver. (1991) 62(3):104-106 105 o r p e R 50 1 50 " '0 b " - MALES t " 40 " -MALES 40 --- FEMALES >- r >- I-- I ~" : -- FEMALES I-- In , , In Z Z LLI 30 W D CJ Z Z 0 0 I-- I-- -< 20 -< 20 I-- I-- In In W W lL LL Z Z 10 10 z z -< w-< h' :::;;: "" 0 0 A SON 0 J F J F 1990 '990

Fig. 3: The seasonal abundance of adult Ixodes Fig. 4: The seasonal abundance of adult rubicundus on Angora goats on the farm Rhipicephalus punctatus on Angora goats on "Preezfontein" in the south western Orange the farm "Pree:zfontein" in the south western Free State (infestation 'density = number of Orange Free State (infestation density = ticks per kg host body mass) number of ticks per kg host body mass)

It is important to know when the ticks State. Journal of the South African Veterinary reserve and on an adjacent farm where tick con· become active in order to remove stock Association 59: 191·194 trol is practised. Journal of the South African 4. Fourie L J, Petney T N, Horak I G, De Jager C Veterinary Association 57: 199-203 from infested camps or apply acaracidal 1989 Seasonal incidence of Karoo paralysis in 7. Macivoji. K M De F, Horak I G 1987 Foot treatment before peak burdens are reach­ relation to the infestation density of female Ix­ abscess in goats in relation to the seasonal abun· ed. On farms in the southern Orange Free odes rubicundus. Veterinary Parasitology 33: dance of adult Amblyomma hebraeum and aJult State and parts of the Karoo, where these 319-328 Rhipicephalus glabroscutatum (: ). precautions were not taken during 1989, 5. Fourie L J, Horak I G 1990 Parasites of cattle in Journal of the South African Veterinary Asso­ the south western Orange Free State. Journal of ciation 58: 113-118 ·the earlier than expected activity of the the South African Veterinary Association 61: 8. Rechav Y 1982 Dynamics of tick populations ticks caused severe stock losses, with 27·28 (Acari: Ixodidae) in the eastern Cape Province reports of up to 100 small stock morta­ 6. Horak I G, Knight M M 1986 A comparison of of South Africa. Journal of Medical Entomology the tick burdens of wild animals in a nature 19: 679-700 ) lities on a single property not uncommon. 1

1 The development of a weather-based 0 model in order to predict the onset of tick 2

d activity is therefore regarded as a high e t priority and is currently receiving atten- a

d tion. • (

r Unlike I. rubicundus the period Of ac­ e R. punctatus Tab1e2 : The relative abundance of the major tick h tivity of commenced one s i species recovered from .goats, sheep and

l month later in 1989 than during 1988. b One could speculate that as this tick nor­ cattle on the farm "Preezfontein" u

P mally prefers the warmer temperatures of

e spring and summer, the colder winter of h t

1989 delayed the onset of its activity du­ Relative abundance y

b ring that year. (%) on:

d Tick species Goats Sheep Cattle e t ACKNOWLEDGEMENTS n We wish to thank Mrs C Human and a Hyalomma r

g Messrs L Barkhuisen, M van Straatten

marginatum ruJipes 0,7 16,3 36,2 e and J van Niekerk. This research was fun­ c n ded by the Wool and Meat Boards, the Hyalomma e c i Foundation for Research Development, truncatum 1,2 0,1 l 7,1

r Bayer Health and Shell Animal e d Health. Ixodes rubicundus 34,3 82,2 3,2 n u

REFERENCES y Rhipicephalus 1. Acocks J P H 1975 Veld types of South Africa 63,3 1,3 9,4 a with accompanying veld type map. Memoirs of punctatus w e the Botanical Survey of South Africa No 40: Other species t 0,5 0,1 44,1 a 128 pp

G 2. Fourie L J, Horak I G, Marais L 1988 An t undescribed Rhipicephalus species associated e

n with field paralysis of Angora goats. Journal of i

b the South African Veterinary Association 59: a 47·49 S 3. Fourie L J, Horak I G, Marais L 1988 The y

b seasonal abundance of adult ixodid ticks on

d Merino sheep in the south-western Orange Free e c u d 106 0038-2809 Jl S.AJr.vet.Ass. (1991) 62(3):104-106 o r p e R