Sambado Samantha, Sipin Terrell J, Rennie Zoe, Larsen Ashley, Cunningham James, Quandt Amy, Sousa Dan, MacDonald Andrew J
University of California Santa Barbara, Santa Barbara, CA, USA.
Stanford University, Stanford, CA, USA.
Proc Biol Sci. 2025 Sep;292(2054):20251365. doi: 10.1098/rspb.2025.1365. Epub 2025 Sep 3.
Mosquito-borne diseases are deeply embedded within ecological communities, with environmental changes-particularly climate change-shaping their dynamics. Increasingly intense droughts across the globe have profound implications for the transmission of these diseases, as drought conditions can alter mosquito breeding habitats, host-seeking behaviours and mosquito-host contact rates. To quantify the effect of drought on disease transmission, we use West Nile virus as a model system and leverage a robust mosquito and virus dataset consisting of over 500 000 trap nights collected from 2010 to 2023, spanning a historic drought period followed by atmospheric rivers. We pair this surveillance dataset with a novel modelling approach that incorporates monthly changes in bird host community competence, along with drought conditions, to estimate the effect of drought severity on West Nile virus risk using panel regression models. Our results show that while drought decreases mosquito abundances, it paradoxically increases West Nile virus infection rates. This counterintuitive pattern probably stems from reduced water availability, which concentrates mosquitoes and pathogen-amplifying bird hosts around limited water sources, thereby increasing disease transmission risk. However, the magnitude of the effect depends critically on mosquito species, suggesting species-specific behavioural traits are key to understanding the effect of drought on mosquito-borne disease risk across real landscapes.
蚊媒疾病深深嵌入生态群落之中，环境变化——尤其是气候变化——塑造着它们的动态。全球范围内日益严重的干旱对这些疾病的传播具有深远影响，因为干旱条件会改变蚊子的繁殖栖息地、寻找宿主行为以及蚊子与宿主的接触率。为了量化干旱对疾病传播的影响，我们以西尼罗河病毒为模型系统，并利用一个强大的蚊子和病毒数据集，该数据集包含2010年至2023年期间收集的超过50万个诱捕夜的数据，涵盖了一个历史性干旱期以及随后的大气河流期。我们将这个监测数据集与一种新颖的建模方法相结合，该方法纳入了鸟类宿主群落易感性的月度变化以及干旱条件，使用面板回归模型来估计干旱严重程度对西尼罗河病毒风险的影响。我们的结果表明，虽然干旱会降低蚊子的数量，但自相矛盾的是，它会增加西尼罗河病毒的感染率。这种违反直觉的模式可能源于可用水量的减少，这使得蚊子和病原体扩增鸟类宿主集中在有限的水源周围，从而增加了疾病传播风险。然而，这种影响的程度关键取决于蚊子的种类，这表明特定物种的行为特征是理解干旱对真实景观中蚊媒疾病风险影响的关键。
