Seasonal population dynamics of the primary yellow fever vector Haemagogus leucocelaenus (Dyar & Shannon) (Diptera: Culicidae) is mainly influenced by temperature in the Atlantic Forest, southeast Brazil

BACKGROUND Southeast Brazil has recently experienced a Yellow Fever virus (YFV) outbreak where the mosquito Haemagogus leucocelaenus was a primary vector. Climatic factors influence the abundance of mosquito vectors and arbovirus transmission. OBJECTIVES We aimed at describing the population dynamics of Hg. leucocelaenus in a county touched by the recent YFV outbreak. METHODS Fortnightly egg collections with ovitraps were performed from November 2012 to February 2017 in a forest in Nova Iguaçu, Rio de Janeiro, Brazil. The effects of mean temperature and rainfall on the Hg. leucocelaenus population dynamics were explored. FINDINGS Hg. leucocelaenus eggs were continuously collected throughout the study, with a peak in the warmer months (December-March). The climatic variables had a time-lagged effect and four weeks before sampling was the best predictor for the positivity of ovitraps and total number of eggs collected. The probability of finding > 50% positive ovitraps increased when the mean temperature was above 24ºC. The number of Hg. leucocelaenus eggs expressively increase when the mean temperature and accumulated precipitation surpassed 27ºC and 100 mm, respectively, although the effect of rainfall was less pronounced. MAIN CONCLUSIONS Monitoring population dynamics of Hg. leucocelaenus and climatic factors in YFV risk areas, especially mean temperature, may assist in developing climate-based surveillance procedures to timely strengthening prophylaxis and control.

背景：巴西东南部近期暴发黄热病毒（Yellow Fever Virus, YFV）疫情，白盾趋血蚊（Haemagogus leucocelaenus）为其主要传播媒介。气候因素可影响蚊媒种群丰度及虫媒病毒（arbovirus）的传播循环。
研究目的：本研究旨在描述此次黄热疫情波及县域内白盾趋血蚊的种群动态特征。
研究方法：2012年11月至2017年2月，在巴西里约热内卢州新伊瓜苏市的一片林区中，采用诱卵器（ovitraps）每两周开展1次卵采集工作。本研究探讨了平均气温与降雨量对白盾趋血蚊种群动态的影响效应。
研究结果：本次研究全程均采集到白盾趋血蚊的卵，种群数量在温暖月份（12月至次年3月）达到峰值。气候变量对该蚊种种群存在滞后效应，采样前4周的气候数据是预测诱卵器阳性率及总采集卵数的最佳指标。当平均气温高于24℃时，诱卵器阳性率超过50%的概率显著升高。当平均气温超过27℃、累计降雨量超过100mm时，白盾趋血蚊的卵量会显著增加，不过降雨量的影响相对较弱。
主要结论：在黄热病毒风险区域开展白盾趋血蚊种群动态及气候因素监测（尤其是平均气温监测），有助于制定基于气候的监测方案，以及时强化预防与防控措施。