Department of Life Sciences, Central University of Tamil Nadu, Thiruvarur, Tamil Nadu, India.
Department of Ecology and Environmental Sciences, School of Life Sciences, Pondicherry University, Puducherry, Tamil Nadu, India.
J Vector Borne Dis. 2020 Jan-Mar;57(1):63-70. doi: 10.4103/0972-9062.308803.
BACKGROUND & OBJECTIVES: Mosquitoes are vectors of several important vector-borne diseases (VBDs) like malaria, dengue, chikungunya, Japanese encephalitis (JE) and lymphatic filariasis (LF). Globally, these VBDs are of major public health concern including India. The information on vector mosquitoes from Thiruvarur district in Tamil Nadu state remains largely either unknown or undocumented. The present study was, therefore, undertaken to find out the seasonal variation in mosquitoes with special reference to dengue vectors in rural areas of Thiruvarur district, Tamil Nadu, India.
Surveillance of immature vector mosquitoes was undertaken from March 2018 to February 2019. The emerged adults were identified to find out the composition of mosquito species prevalent in the district. The seasonal variations of the mosquitoes especially dengue vectors were analysed for summer (March-July) spring (August-November) and winter (December-February) seasons in all the blocks of Thiruvarur district.
A total of 4879 mosquitoes emerged from the immature collection and the species identification revealed the prevalence of both vector and non-vector species. Five important mosquito vectors collected were -Aedes albopictus, Ae. aegypti, Culex tritaeniorhynchus, Cx. gelidus, and Cx. quinquefasciatus. Other mosquito species collected were Lutzia fuscana, Anopheles barbirostris, An. subpictus, and Armigeres (Armigeres) subalbatus. During the spring season, the dengue vectors showed high indices of breateau index (BI), ranging from 16 to 120; besides, container index (CI) ranging from14.29 to 68.57 and pupal index (PI) from 53.33 to 295 among the study blocks. The major breeding sites were discarded plastic containers, discarded tyres, open sintex tanks (water storage tanks), cement tanks, discarded fibre box, pleated plastic sheets, tree holes, bamboo cut stumps, coconut spathe, and coconut shells.
INTERPRETATION & CONCLUSION: The immature vector surveillance revealed seasonal variations in the entomological indices of Aedes breeding potential. The high indices observed indicate high Aedes breeding density and, therefore, a higher risk for dengue/chikungunya outbreaks in rural areas of Thiruvarur district. The present finding warrants intensive surveillance and follow up vector control measures to avert outbreaks and prevent vector-borne diseases. Health education and the community participation in awareness camps prior to monsoon and societal commitment will help in strengthening source reduction, anti-larval operations and anti-adult measures to tackle vector-borne diseases especially dengue.
蚊子是疟疾、登革热、基孔肯雅热、日本脑炎（JE）和淋巴丝虫病（LF）等几种重要媒介传播疾病（VBD）的传播媒介。在全球范围内，这些 VBD 是主要的公共卫生关注点，包括印度。泰米尔纳德邦蒂鲁瓦鲁尔区的媒介蚊子信息在很大程度上仍然未知或未记录。因此，本研究旨在了解泰米尔纳德邦蒂鲁瓦鲁尔区农村地区蚊子的季节性变化，特别是登革热媒介。
从 2018 年 3 月至 2019 年 2 月对幼蚊进行监测。对出现的成虫进行鉴定，以确定该地区流行的蚊子种类组成。分析了所有蒂鲁瓦鲁尔区街区夏季（3 月至 7 月）、春季（8 月至 11 月）和冬季（12 月至 2 月）蚊子的季节性变化，特别是登革热媒介。
从幼蚊采集共出现了 4879 只蚊子，物种鉴定显示了既有媒介又有非媒介物种的存在。共收集到 5 种重要的蚊子媒介，分别为白纹伊蚊、埃及伊蚊、三带喙库蚊、致倦库蚊和淡色库蚊。其他收集到的蚊子种类包括卢氏细蚊、嗜人按蚊、暗纹伊蚊和阿蚊（阿蚊）subalbatus。在春季，登革热媒介的布雷图指数（BI）较高，范围为 16 至 120；此外，容器指数（CI）范围为 14.29 至 68.57，幼蚊指数（PI）范围为研究区各街区的 53.33 至 295。主要滋生地是废弃的塑料容器、废弃的轮胎、敞开的辛太克斯水箱（储水罐）、水泥水箱、废弃的纤维箱、褶皱塑料片、树洞、竹桩、椰子叶鞘和椰子壳。
幼蚊监测显示出蚊子繁殖潜力的昆虫学指标的季节性变化。观察到的高指数表明，埃及伊蚊的繁殖密度较高，因此蒂鲁瓦鲁尔区农村地区登革热/基孔肯雅热爆发的风险较高。目前的发现需要进行强化监测，并采取后续的病媒控制措施，以避免暴发和预防媒介传播疾病。在季风前和社会承诺期间开展健康教育和社区参与意识运动，将有助于加强源头减少、幼虫防治和成虫防治措施，以应对登革热等媒介传播疾病。
