Journal of Entomology and Zoology Studies 2014; 2 (6): 233-239 Survey of mosquito vector abundance in and around ISSN 2320-7078 JEZS 2014; 2 (6): 233-239 tribal residential areas © 2014 JEZS www.entomoljournal.com Received: 21-10-2014 P. Suganthi, M. Govindaraju, V. Thenmozhi and B. K. Tyagi Accepted: 12-11-2014 Abstract P. Suganthi Mosquitoes are having high capacity to transmit pathogens (parasites and virus) to humans causing Research scholar, Department of Environmental Biotechnology, mosquito-borne diseases. This is a major public health problem in most of tropical and subtropical School of Environmental Sciences countries. Its control is becoming more and more difficult due to the spread of resistance of the vector. Bharathidasan University, The study was conducted to estimate the mosquito larval density, diversity and preference breeding sites Tiruchirappalli -620024, Tamil of Aedes, Culex and Anopheles mosquito species in Sitheri hills, Dharmapuri district, Tamil Nadu, India. Nadu, India. Larval samples were collected by dipping method using pipette dipper depending on container types for all seasons of the year 2012. The collected larvae were raised to adults for identification. A total of 460 M. Govindaraju water containers were inspected in eight villages. The study confirm the presence of eight dominant Assistant professor, Department of mosquito species in the study area namely Aedes aegypti (45%), Aedes vittatus (23%) Aedes albopictus Environmental Biotechnology, (15%), Culex quinquefasciatus (9%), Anopheles subpictus (4%), Culex gelidus (2%), Culex nilgricus School of Environmental Sciences, (1%) and Culex tritaeniorhynchus (1%). It’s observed that the major breeding sources are mud pot, Bharathidasan University, grinding stone, cement cistern, metal vessels, tree hole, rocky hole, stagnant water lock area, rice field, Tiruchirappalli -620024, Tamil waste tyre, cement tank, canal and plastic container. The present study concludes that the species of Nadu, India. Aedes aegypti and Aedes vittatus was most predominant container breeding mosquitoes and the villages V. Thenmozhi of Sitheri and Selur having more number of mosquito larvae populations in the study area. The study is Centre for Research in Medical useful for creating awareness and control of mosquito-borne diseases and its breeding sites. Entomology (ICMR), No. 4, Keywords: Aedes aegypti, Aedes vittatus, container survey, mosquito-borne diseases, mosquito larvae. Sarojini Street, Chinna Chokkikulam, Madurai - 625002, Tamil Nadu, India. 1. Introduction Mosquitoes are not only a nuisance, but are also responsible for the spread of a wide range of B. K. Tyagi diseases including Malaria, Yellow fever, Dengue, Chikungunya, West Nile virus and Rift Centre for Research in Medical Valley fever. These mosquito borne diseases are a leading health problem. Around the world Entomology (ICMR), No. 4, more than 700 million people suffer from mosquito-borne diseases and approximately two Sarojini Street, Chinna million people die in every year [1]. Mosquitoes are unquestionably the most medically Chokkikulam, Madurai - 625002, Tamil Nadu, India. important arthropod vectors of disease. The maintenance and transmission of the pathogens are absolutely dependent on the availability of competent mosquito vectors. Among the mosquito borne diseases dengue is a serious problem in India. Over 2.5 billion people are now at risk from dengue. WHO currently estimates there may be 50-100 million dengue infection worldwide every year [2]. In India, Dengue Fever (DF), Dengue Haemorrhagic Fever (DHF) and Dengue Shock Syndrome (DSS) have been documented in different parts of the country [3] including southern part of India [4, 5]. Among the thirteen genera of the family Culicidae, genus Aedes is considered dangerous because of their significant public health threat all over the world. One of the dominant species of Aedes showing wide geographic distribution and spanning both temperate and tropical climate zones is Aedes aegypti (L). It is a primary vector of dengue viruses. The Ae. aegypti is well adapted to living with people and in much of the world is predominantly found among human settlements. Immature Ae. aegypti develops in artificial and natural water-holding containers located in and around human habitations. The problem of dengue has now been extended to several rural areas [6]. In Tamil Nadu, among the 32 districts, dengue cases have been reported Correspondence: in 29 districts between the years of 1998 to 2005. Which includes, DSS /DHF outbreaks were M.Govindaraju presented in Chennai, [6] (2001) Nagercoil (2003) and Tiruchirappalli (2003). The DHF Assist. prof., outbreaks presented in Krishnagiri and Dharmapuri districts during 2001[7]. In 2012, a total of Department of Environmental 9,000 cases and 50 deaths were reported in Madurai, Tirunelveli and Kanyakumari districts [8]. Biotechnology, School of A primary determinant of adult mosquito population density concerns the types and number of Environmental Sciences, Bharathidasan University, containers in a given environment. Adult production is unevenly distributed across potential Tiruchirappalli -620024, Tamil larval development sites. In most cases, a few key types of containers are responsible for a Nadu, India ~ 233 ~ Journal of Entomology and Zoology Studies large proportion of the larval, pupal and thus adult, production Eastern Ghats of Tamil Nadu, within the geographical limit of [9]. According to the Land use and land cover changes, such as 78°15’00’’ - 78°45’00’’E longitude and 11°44’00’’- deforestation, agricultural expansion, infrastructure 12°08’00’’N latitude. The study area situated at development, urbanization and human population growth Pappireddipatti Taluk in Dharmapuri district, Tamil Nadu, contribute to the proliferation of breeding sites of mosquitoes India. This is a hill area consists of 59 hamlets and four forest [10]. These environmental or land-use modifications also affect ranges such as Harur, Morappur, Theerthamalai and climate processes that are likely to support rapid growth of Kottapatti. The sitheri hills have six forest types are evergreen, mosquitoes and parasites in regions where there has previously semi-evergreen, riparian, dry mixed deciduous, dry deciduous been a low temperature restriction on transmission. The scrub and southern thorn scrub forest classified by Champion present study to investigate the species specific mosquito and Seth (1968). The study area mean annual temperature are habitats and abundance of mosquitoes in sitheri hills. varies from 18 °C (in winter) to 40 °C (in summer) and maximum annual rainfall 900 mm respectively. Many narrow 2. Materials and Methods valleys (rivers) are presented such as Varattar, Kallar, 2.1 Study Area Kambalai and Anaimaduvu. Topographically, altitude of the The mosquito larval survey was carry out from January 2012 hills ranges from 1463 to 3187 ft. The location map of the to December 2012 in Sitheri hills (also called as Chitteri). study area is given in Fig. 1. The hills has an area about 654.52 sq.km which is located in Fig 1: Study Area Map 2.2 Larval Collection inspected X100 During the survey, larvae were collected in all the containers and accessible tree holes (Fig. 2). Larvae collection was Breteau Index (Bl): Number of positive containers per 100 carried outdoors by dipping method, using pipette dipper houses inspected depending on container type and location. The number, type and water condition of containers which serve as a potential Bl = Number of positive containers/Number of houses breeding site was examined and the following indexes are inspected X100 calculated. The collected larvae and pupae were kept in the laboratory for adult emergence at room temperature (27±2 ᵒC). Pupae Index (Pl): Number of pupae per 100 houses The emerged adult mosquitoes were then pinned and identified. Pl = Number of pupae/Number of houses inspected X100 House index (Hl): Percentage of houses infected with larvae 2.3 Identification of Collected Larvae and/or pupae The collected specimens were preserved in plastic vials for further identification. Immature forms of mosquito larvae were HI = Number of Houses infected/Number of Houses inspected collected by dipper method, reared in metal trays in the X100 laboratory and fed with larval feed. The emerged adults were collected and stored in vials and all the collected mosquitoes Container Index (Cl): Percentage of water holding containers were identified in Centre for Research in Medical Entomology infected with larvae or pupae. (CRME), Madurai using the standard keys [11]. Cl = Number of positive containers/Number of containers ~ 234 ~ Journal of Entomology and Zoology Studies Fig 2: Sources of mosquito larvae breeding habitats. a). Mud pot, b). Grinding stone, c). Cement cistern, d). Metal vessels, e). Tree hole, f) Rocky hole, g). Stagnant water lock area, h). Rice field, i).Waste tyre, j.) Cement tank. k). Canal, l.) Plastic container. 3. Results without white line. A silvery basal band is presented in A total of 368, both artificial and natural containers were abdomen of Ae. albopictus. surveyed as potential mosquito larvae breeding habitats in Another important mosquito in the study area is Culex species. Sitheri hills, presented in Table 1. The morphology and The Cx. quinquefasciatus species is a highly presented. It is a taxonomy of the collected adult mosquitoes were identified filariasis vector and the external morphology was observed by based on the examination of the taxonomic