EIDs: West Nile virus in the Central Flyway

Introduction/Objectives: Climate change is slowly altering environmental conditions. It is also enabling spread of vector-borne diseases to new geographic areas. In the Central Flyway region, which includes the region of Texas, Oklahoma, and Kansas to the Dakotas, rising temperatures and changing precipitation patterns are expanding the range of diseases like West Nile virus (WNV). Warmer winters in northern parts of the Central Flyway like North Dakota and South Dakota, and warmer winters at the southern end in Texas, have been linked to increased WNV cases. Texas led the United States in cases reported by residents in 2024. We examine how warmer winters in the Dakotas and Texas contribute to the proliferation of mosquito species-Culex tarsalis in the Dakotas and Culex quinquefasciatus in Texas-both of which are primary vectors for WNV. The objective is to explore the relationship between climate change, these mosquito species, and the spread of West Nile Virus, and to highlight the urgency of adaptive public health strategies.

Methods: Mixed methods were used, researching both qualitative evidence from climate data, disease surveillance reports, and health studies specific to the Central Flyway region, along with quantitative data from recent disease surveillance. The analysis includes empirical studies on how climate change affects the distribution of mosquito species, including C. tarsalis and C. quinquefasciatus. Case studies of local health system responses to these emerging diseases are also reviewed.

Results: Research analysis revealed patterns showing how increasing temperatures and changes in precipitation in the Central Flyway are expanding the range of C. tarsalis and C. quinquefasciatus. Warmer winters in the Dakotas are resulting in higher populations of C. tarsalis, leading to higher incidences of WNV in the northern parts of the Central Flyway. Warmer winters in Texas have caused a similar rise in C. quinquefasciatus. This is further contributing to the spread of WNV. The study shows a need for health systems that are integrated in ways that consider both environmental changes and health system capacity to handle emerging infectious diseases due to climate change.

Conclusions: A public health approach with multiple facets is needed to address the growing threat of West Nile Virus in the Central Flyway. Some of the key recommendations to address this threat include strengthening of local, regional and national disease surveillance systems and improving antimicrobial stewardship. In addition, regional cooperation is needed to prevent the further spread of West Nile Virus. Policy development and increased healthcare capacity are both needed to address the impact of climate-driven disease spread.