JAMA Network, Sept. 13, 2023The number of West Nile virus cases will vary greatly from year to year. “The effect of climate on vector-borne diseases is very complicated,” said Scott Weaver, PhD, director of the Institute for Human Infections and Immunity at the University of Texas Medical Branch. Warmer temperatures are extending the geographic distribution of mosquitoes and ticks in the US. But rates of human disease also depend on the habitats and migratory patterns of animal hosts that harbor the pathogens that infect mosquitoes and ticks. "These are all being affected by climate change," Weaver said.

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