Regional Director of Health Services Office, Gampaha District, Gampaha, Sri Lanka.
Department of Zoology and Environmental Management, Faculty of Science, University of Kelaniya, Dalugama, Sri Lanka.
Parasit Vectors. 2022 Apr 27;15(1):148. doi: 10.1186/s13071-022-05261-3.
The lack of information on behavioural patterns of Aedes aegypti and Aedes albopictus has become a significant limitation in vector control and disease management programmes. Therefore, the current study was focused on determining some bionomics aspects: breeding, resting, host-seeking and feeding preferences of Ae. aegypti and Ae. albopictus in Sri Lanka.
Larval and adult surveys were conducted from April 2017 to April 2019 monthly in six selected Medical Officer of Health (MOH) areas in Gampaha Distinct, Western province, Sri Lanka, representing urban, suburban and rural settings. Resting preferences of adult mosquitoes were observed from indoor and outdoor places using a Prockopack aspirator. The information on resting height, surface, material and locality was recorded. Human-baited double-net traps were used to determine the host-seeking time of Aedes mosquitoes. Statistical differences in the spatial distribution of mosquitoes in selected MOH areas and prevalence of vectors were analysed using general linear model (GLM). A chi-square test was used to analyse the resting behaviour.
Total of 19,835 potential breeding sites were examined at 13,563 premises, and 18.5% (n = 1856) were positive for Aedes larvae. Distribution of Ae. aegypti and Ae. albopictus was statistically significant at species level (df = 1; F = 137.134; P < 0.05 GLM) and study setting (df = 2; F = 8.125; P < 0.05). Aedes aegypti breeding was found mainly in temporary removals (18.8%; n = 34), discarded non-degradables (12.15%; n = 22) and tyres (9.95%; n = 18). Natural (14.7%; n = 246) and temporary removals (13.6%; n = 227) and discarded non-reusable items were the key ovipositing sites for Ae. albopictus. In the adult mosquito survey, the majority was comprised of Ae. albopictus (54.5%; n = 999), which denoted exophilic nature (90.8%; n = 758), and 45.5% (n = 835) represented by Ae. aegypti mosquitoes who were mainly endophilic (84.3%; n = 842). Aedes aegypti rested on cloth hangings and curtains, followed by the furniture, while Aedes albopictus was predominant in outdoor vegetation. In both vectors, biting patterns denoted a typical diurnal pattern with two peaks of host-seeking and biting activity in the morning and afternoon.
The majority (80%) of the larval habitats were artificial containers. The use of larvicides for vector control as the prominent measure is questionable since applying these chemicals may target only 20% of the total breeding grounds, which are permanent. The resting places of adult mosquitoes are mainly indoors. Therefore, using thermal space spraying of insecticide may not be appropriate, and indoor residual spraying is recommended as a suitable intervention to target adult mosquitoes. This study warrants a holistic vector control approach for all medically important mosquitoes and insects, ensuring the rational use of finance and resources.
缺乏埃及伊蚊和白纹伊蚊行为模式的信息已成为病媒控制和疾病管理计划的重大限制。因此，目前的研究集中于确定一些生物生态学方面：斯里兰卡埃及伊蚊和白纹伊蚊的繁殖、休息、寻找宿主和摄食偏好。
2017 年 4 月至 2019 年 4 月，每月在斯里兰卡西部省加姆帕哈区的 6 个选定的卫生官员地区进行幼虫和成虫调查，代表城市、郊区和农村环境。使用 Prockopack 吸气器从室内和室外观察成蚊的休息偏好。记录休息高度、表面、材料和位置的信息。使用人诱双网捕蚊器确定伊蚊的寻宿主时间。使用一般线性模型（GLM）分析选定的 MOH 地区蚊子的空间分布和媒介的流行情况的差异。使用卡方检验分析休息行为。
在 13563 个场所共检查了 19835 个潜在的繁殖场所，其中 18.5%（n=1856）有埃及伊蚊幼虫。埃及伊蚊和白纹伊蚊的分布在物种水平（df=1；F=137.134；P<0.05 GLM）和研究环境（df=2；F=8.125；P<0.05）上具有统计学意义。埃及伊蚊的繁殖主要发生在临时容器（18.8%；n=34）、不可降解的废物（12.15%；n=22）和轮胎（9.95%；n=18）中。天然（14.7%；n=246）和临时容器（13.6%；n=227）以及不可重复使用的废物是白纹伊蚊的关键产卵地点。在成蚊调查中，大多数是白纹伊蚊（54.5%；n=999），表示嗜外生性（90.8%；n=758），45.5%（n=835）是埃及伊蚊，主要是嗜内生性（84.3%；n=842）。埃及伊蚊在布帘和窗帘上休息，其次是家具，而白纹伊蚊则主要在户外植被中。在这两种蚊子中，叮咬模式表示出典型的昼夜模式，上午和下午有两个寻找宿主和叮咬活动的高峰。
大多数（80%）幼虫栖息地都是人工容器。由于使用化学药剂进行病媒控制可能只能针对 20%的永久性总繁殖地，因此使用幼虫药剂作为主要措施是值得质疑的。成蚊的休息场所主要在室内。因此，使用热空气喷雾杀虫剂可能不适合，建议使用室内滞留喷洒作为针对成蚊的合适干预措施。这项研究需要采取整体的病媒控制方法来控制所有具有医学重要性的蚊子和昆虫，以确保合理利用资金和资源。
