Osalla Josephine, Gouagna Louis-Clement, Rotich Gilbert, Nzilani Maureen, Safari Penina, Senagi Kennedy, Mutuku Francis, Torto Baldwyn, Tchouassi David P
International Centre of Insect Physiology and Ecology, P.O Box 30772-00100, Nairobi, Kenya.
MIVEGEC, Université de Montpellier, IRD, CNRS, Montpellier, France.
Sci Rep. 2025 Jul 1;15(1):21787. doi: 10.1038/s41598-025-05408-z.
The coastal region of Kenya has emerged as a focal point for urban dengue virus transmission driven by Aedes aegypti as the primary vector. To gain a deeper understanding of the epidemiological situation, we carried out a year-long longitudinal study (December 2021- November 2022) of the population dynamics of A. aegypti through weekly mosquito surveys using ovitrap and CO-baited Biogents (BG) mosquito traps in Ukunda, an urban township in the coastal region. Aedes eggs laid in ovitraps were exclusively A. aegypti with 80.8% mean hatch rate. A total of 35,109 adult A. aegypti were captured, with twice as many females than males. The density of adult A. aegypti trap captures varied monthly, but there was no discernible delineation by season. Aedes aegypti fed more on humans (human blood index = 0.72). Two dengue-2 virus RNA was detected in two blood-fed specimens that had fed on humans. Multiple linear regression model indicated 59% variation in adult female abundance explained by weather variables including daily range in wind speed (82.9%) and temperature (17.1%). In contrast, random forest model revealed 83% variation in egg abundance attributed to weather variables, being positively influenced by mean daily temperature, wind speed, relative humidity and negatively by total precipitation. Our results confirm year-round vector presence and active circulation of dengue virus indicative of endemicity in urban Kenya. The findings highlight the importance of short-term climatic factors as predictors of A. aegypti dynamics of value in surveillance and control of arboviral diseases such as dengue.
肯尼亚沿海地区已成为由埃及伊蚊作为主要传播媒介驱动的城市登革热病毒传播的焦点。为了更深入了解流行病学情况，我们在沿海地区的一个城市小镇乌昆达开展了为期一年（2021年12月至2022年11月）的纵向研究，通过使用诱蚊产卵器和二氧化碳诱捕的Biogents（BG）诱蚊器每周进行蚊虫调查，研究埃及伊蚊的种群动态。诱蚊产卵器中产下的埃及伊蚊卵均为埃及伊蚊，平均孵化率为80.8%。共捕获35109只成年埃及伊蚊，雌性数量是雄性的两倍。成年埃及伊蚊诱捕器捕获量的密度每月有所变化，但没有明显的季节划分。埃及伊蚊吸食人类血液的比例更高（人类血液指数=0.72）。在两只吸食人类血液的标本中检测到两种登革热2型病毒RNA。多元线性回归模型表明，成年雌性伊蚊数量的59%变化可由天气变量解释，包括风速（82.9%）和温度（17.1%）的日变化范围。相比之下，随机森林模型显示，卵数量的83%变化归因于天气变量，平均每日温度、风速、相对湿度对其有正向影响，总降水量对其有负向影响。我们的结果证实了全年存在传播媒介以及登革热病毒的活跃传播，这表明肯尼亚城市存在地方流行性。研究结果突出了短期气候因素作为埃及伊蚊动态预测指标的重要性，这对于登革热等虫媒病毒疾病的监测和控制具有重要价值。
