Climate change and extreme weather events to intensify West Nile virus activity
Abstract
Vector-borne zoonotic diseases pose a substantive risk to public health worldwide, yet predicting outbreaks at scales useful for public health response remains a critical challenge. Transmitted by Culex mosquitoes, West Nile virus is the leading cause of arboviral disease in the United States, progressing to neuroinvasive disease in approximately 1% of infections. Arizona's record-breaking 2021 outbreak, with 1,715 reported human cases and 127 deaths exemplifies this growing burden. Using a decade of mosquito surveillance data coupled with time-lagged weather patterns in a random forest framework, we developed spatial models predicting Culex abundance and West Nile virus occurrence across Arizona at weekly temporal and fine spatial resolution. Our weighted models classified viral occurrence with 98.9% accuracy and explained 65.3% of weekly variation in county-level human cases, with human cases lagging modeled activity by one week. Neither mosquito abundance nor viral occurrence declined at the extreme temperatures characteristic of Arizona summers, suggesting that thermal refugia sustain transmission. Drought-monsoon cycling, rather than temperature alone, emerged as the primary driver of West Nile activity, and projections through 2100 indicate intensifying activity under all climate change scenarios.
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BibTeX
@misc{bliss2026climate,
title = {{Climate change and extreme weather events to intensify West Nile virus activity}},
author = {Desiree Andersen Bliss and Gracie Fischer and Kacey Ernst and Nathan Schumaker and Michael A. Riehle and Elizabeth Hilborn and Stephanie DeFlorio-Barker and Leigh Combrink},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.28.762036},
url = {https://www.biorxiv.org/content/10.64898/2026.10.28.762036v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Climate change and extreme weather events to intensify West Nile virus activity
AU - Desiree Andersen Bliss
AU - Gracie Fischer
AU - Kacey Ernst
AU - Nathan Schumaker
AU - Michael A. Riehle
AU - Elizabeth Hilborn
AU - Stephanie DeFlorio-Barker
AU - Leigh Combrink
PY - 2026
DA - 2026/10/28
PB - bioRxiv
DO - 10.64898/2026.10.28.762036
UR - https://www.biorxiv.org/content/10.64898/2026.10.28.762036v1
AB - Vector-borne zoonotic diseases pose a substantive risk to public health worldwide, yet predicting outbreaks at scales useful for public health response remains a critical challenge. Transmitted by Culex mosquitoes, West Nile virus is the leading cause of arboviral disease in the United States, progressing to neuroinvasive disease in approximately 1% of infections. Arizona's record-breaking 2021 outbreak, with 1,715 reported human cases and 127 deaths exemplifies this growing burden. Using a decade of mosquito surveillance data coupled with time-lagged weather patterns in a random forest framework, we developed spatial models predicting Culex abundance and West Nile virus occurrence across Arizona at weekly temporal and fine spatial resolution. Our weighted models classified viral occurrence with 98.9% accuracy and explained 65.3% of weekly variation in county-level human cases, with human cases lagging modeled activity by one week. Neither mosquito abundance nor viral occurrence declined at the extreme temperatures characteristic of Arizona summers, suggesting that thermal refugia sustain transmission. Drought-monsoon cycling, rather than temperature alone, emerged as the primary driver of West Nile activity, and projections through 2100 indicate intensifying activity under all climate change scenarios.
SN - 2692-8205
ER -