Dev V, Khound K, Tewari G G
National Institute of Malaria Research (Field Station), Guwahati, Assam, India.
National Vector Borne Disease Control Programme, Government of Assam, Guwahati, Assam, India.
WHO South East Asia J Public Health. 2014 Jan-Mar;3(1):51-59. doi: 10.4103/2224-3151.206885.
Dengue is rapidly becoming established in north-east India and spreading, on account of rapid urbanization and population movement, with reported morbidity and attributable death cases. This study aims to determine the seasonal abundance of Aedes (Stegomyia) albopictus and Aedes (Stegomyia) aegypti in Guwahati metropolis and suburban settlements; to characterize the breeding resources for these mosquitoes; and to ascertain the status of their susceptibility to adulticides and larvicides.
Mosquito larval surveys were carried out in different localities in both Guwahati city and adjoining suburbs from January to December 2013, to determine the seasonal abundance of disease vectors and their breeding preferences. The insecticide susceptibility status of mosquito adults and larval populations of both Aedes aegypti and Aedes albopictus was ascertained, using World Health Organization standard diagnostic concentrations and test procedures.
The study revealed that both Aedes aegypti and Aedes albopictus are widely abundant in Guwahati city and suburbs, and breeding in a wide variety of resources. Aedes albopictus, however, was the predominant mosquito species in suburbs, breeding preferentially in flower vases, cut-bamboo stumps and leaf axils. Aedes aegypti was the most common in the city, breeding predominantly in discarded tyres, cement tanks and used battery boxes. Both Aedes aegypti and Aedes albopictus were resistant to dichlorodiphenyltrichloroethane (DDT; 4%), but susceptible to malathion (5%), and exhibited a varied response to pyrethroids. However, larval populations of both these mosquito species were susceptible to larvicides, including malathion (1.0 mg/L), temephos (0.02 mg/L) and fenthion (0.05 mg/L), at much lower dosages than diagnostic concentrations.
Given the seasonal abundance and case incidence in city areas, it is highly probable that Aedes aegypti is the predominant mosquito vector transmitting dengue virus. The study results have direct relevance for the state dengue-control programme, for targeting interventions and averting outbreaks and spread of disease.
由于快速的城市化和人口流动，登革热在印度东北部迅速蔓延并站稳脚跟，出现了发病率和死亡病例的报告。本研究旨在确定古瓦哈蒂市及其郊区白纹伊蚊和埃及伊蚊的季节丰度；描述这些蚊子的繁殖资源；并确定它们对杀虫剂和杀幼虫剂的敏感性状况。
2013年1月至12月在古瓦哈蒂市及其毗邻郊区的不同地点进行了蚊虫幼虫调查，以确定病媒的季节丰度及其繁殖偏好。使用世界卫生组织标准诊断浓度和测试程序确定埃及伊蚊和白纹伊蚊成虫及幼虫种群的杀虫剂敏感性状况。
研究表明，埃及伊蚊和白纹伊蚊在古瓦哈蒂市及其郊区广泛存在，且在多种资源中繁殖。然而，白纹伊蚊是郊区的主要蚊种，优先在花瓶、砍下的竹桩和叶腋中繁殖。埃及伊蚊在城市中最为常见，主要在废弃轮胎、水泥池和用过的电池盒中繁殖。埃及伊蚊和白纹伊蚊均对滴滴涕（4%）具有抗性，但对马拉硫磷（5%）敏感，并且对拟除虫菊酯表现出不同的反应。然而，这两种蚊虫的幼虫种群对杀幼虫剂敏感，包括马拉硫磷（1.0毫克/升）、双硫磷（0.02毫克/升）和倍硫磷（0.05毫克/升），其剂量远低于诊断浓度。
鉴于城市地区的季节丰度和病例发生率，埃及伊蚊很可能是传播登革热病毒的主要病媒。研究结果与该州的登革热控制计划直接相关，有助于确定干预目标并避免疾病爆发和传播。
