Florida Keys Mosquito Control District, Marathon, Florida, United States of America.
University of Florida, Institute of Food and Agricultural Sciences, Department of Entomology and Nematology, Florida Medical Entomology Laboratory, Vero Beach, Florida, United States of America.
PLoS Negl Trop Dis. 2024 Aug 13;18(8):e0012350. doi: 10.1371/journal.pntd.0012350. eCollection 2024 Aug.
Aedes aegypti is an important vector of dengue virus and other arboviruses that affect human health. After being ingested in an infectious bloodmeal, but before being transmitted from mosquito to human, dengue virus must disseminate from the vector midgut into the hemocoel and then the salivary glands. This process, the extrinsic incubation period, typically takes 6-14 days. Since older mosquitoes are responsible for transmission, understanding the age structure of vector populations is important. Transcriptional profiling can facilitate predictions of the age structures of mosquito populations, critical for estimating their potential for pathogen transmission. In this study, we utilized a two-gene transcript model to assess the age structure and daily survival rates of three populations (Key West, Marathon, and Key Largo) of Ae. aegypti from the Florida Keys, United States, where repeated outbreaks of autochthonous dengue transmission have recently occurred. We found that Key Largo had the youngest Ae. aegypti population with the lowest daily survival rate, while Key West had the oldest population and highest survival rate. Across sites, 22.67% of Ae. aegypti females were likely old enough to transmit dengue virus (at least 15 days post emergence). Computed estimates of the daily survival rate (0.8364 using loglinear and 0.8660 using non-linear regression), indicate that dengue vectors in the region experienced relatively low daily mortality. Collectively, our data suggest that Ae. aegypti populations across the Florida Keys harbor large numbers of older individuals, which likely contributes to the high risk of dengue transmission in the area.
埃及伊蚊是登革病毒和其他影响人类健康的虫媒病毒的重要传播媒介。在摄入具有感染性的血餐后，但在蚊子将病毒传播给人类之前，登革热病毒必须从媒介的中肠传播到血腔，然后再传播到唾液腺。这个过程，即外潜伏期，通常需要 6-14 天。由于较老的蚊子负责传播，因此了解媒介种群的年龄结构很重要。转录谱分析可以方便地预测蚊子种群的年龄结构，这对于估计它们传播病原体的潜力至关重要。在这项研究中，我们利用双基因转录模型评估了来自美国佛罗里达群岛的三个埃及伊蚊种群（基韦斯特、马拉松和基拉戈）的年龄结构和日存活率，这些地区最近发生了反复的本地登革热传播疫情。我们发现，基拉戈的埃及伊蚊种群最年轻，日存活率最低，而基韦斯特的种群最老，存活率最高。在各个地点，有 22.67%的埃及伊蚊雌蚊可能已经到了足以传播登革热病毒的年龄（至少在出现后 15 天）。使用对数线性和非线性回归计算得出的日存活率估计值（分别为 0.8364 和 0.8660）表明，该地区的登革热媒介的日死亡率相对较低。总的来说，我们的数据表明，佛罗里达群岛的埃及伊蚊种群中存在大量的老年个体，这可能是该地区登革热传播风险高的原因之一。
