Instituto de Medicina Regional, Universidad Nacional del Nordeste. Av. Las Heras 727 3500, Resistencia, Chaco, Argentina.
Instituto de Medicina Regional, Universidad Nacional del Nordeste. Av. Las Heras 727 3500, Resistencia, Chaco, Argentina; CONICET, CCT Nordeste, Corrientes, Argentina.
Acta Trop. 2020 Dec;212:105678. doi: 10.1016/j.actatropica.2020.105678. Epub 2020 Aug 24.
Aedes aegypti is the main vector of dengue virus in South America. In the last fifteen years, Argentina has suffered three large dengue outbreaks: one in 2009, another one in 2016 and the current 2020 outbreak, with 26,000, 66,000 and more than 43,000 confirmed cases, respectively. These outbreaks are associated with the circulation of the virus in neighboring countries due to the constant movement of people across the frontier. In 2009, the main province affected was Chaco province, with 11,037 confirmed cases (50% of total cases). Thus, the aim of this study was to characterize the temporal oviposition rate of Aedes aegypti in Resistencia, the capital city of this province, in relation to meteorological variables. Mosquitoes were sampled weekly, from April 2015 to March 2017, using ovitraps located in houses randomly selected within the urban area. Oviposition rate was evaluated by means of the total number of eggs collected per week and the proportion of positive ovitraps per week. The coefficient of variation for these two indicators was estimated for the whole study period and then compared using the Wilcoxon Pair test. A generalized linear model (GLM) was performed to infer association between meteorological variables and oviposition rate without time lag and with a time lag of 1 to 4 weeks, considering the biology of this mosquito species. Comparisons between the coefficient of variation of egg number versus the proportion of positive ovitraps showed significant differences, being the former more variable than the latter. The most significant time lag was 2 weeks for the minimum temperature. The number of Ae. aegypti eggs increased 4.05 times when the minimum temperature increased 1°C two weeks before, and decreased 0.69 times with an increase of 1 unit in relative humidity. No eggs were collected when the temperature was below 8°C. The oviposition rate was associated with the increase in the critical minimum temperature (over 8°C) and the weekly frequency of precipitation and dissociated with relative humidity. The maximum oviposition rate was recorded between November and January of both years. The GLM could not explain the relation between meteorological variables and the proportion of positive ovitraps. The peaks of Ae. aegypti egg abundance occurred simultaneously with dengue autochthonous cases recorded in Chaco province, resulting in a good indicative of the period of greatest epidemiological risk.
埃及伊蚊是南美的主要登革热病毒媒介。在过去的十五年中，阿根廷遭受了三次大规模的登革热疫情：一次是在 2009 年，另一次是在 2016 年，目前是 2020 年爆发，分别有 26000、66000 和超过 43000 例确诊病例。这些疫情与邻国的病毒传播有关，因为人们不断跨越边境。2009 年，受影响的主要省份是查科省，有 11037 例确诊病例（占总病例数的 50%）。因此，本研究的目的是描述该省首府雷西斯滕西亚市埃及伊蚊的定时产卵率与气象变量之间的关系。从 2015 年 4 月至 2017 年 3 月，每周使用位于城市地区随机选择的房屋内的诱卵器采集蚊子。通过每周收集的卵总数和每周阳性诱卵器的比例来评估产卵率。对整个研究期间的这两个指标的变异系数进行了估计，然后使用 Wilcoxon 配对检验进行比较。在没有时间滞后和 1 至 4 周时间滞后的情况下，使用广义线性模型（GLM）推断气象变量与产卵率之间的关联，同时考虑到这种蚊子物种的生物学特性。卵数的变异系数与阳性诱卵器比例的比较显示出显著差异，前者比后者更具变异性。最低温度的最显著时间滞后为 2 周。当最低温度在两周前升高 1°C 时，埃及伊蚊卵的数量增加了 4.05 倍，当相对湿度增加 1 个单位时，卵的数量减少了 0.69 倍。当温度低于 8°C 时，没有采集到卵。产卵率与临界最低温度（高于 8°C）的增加以及每周降水频率有关，与相对湿度无关。最大产卵率出现在 2015 年和 2016 年的 11 月至 1 月之间。GLM 无法解释气象变量与阳性诱卵器比例之间的关系。埃及伊蚊卵丰度的峰值与查科省记录的本地登革热病例同时发生，这很好地表明了最具流行病学风险的时期。
