Drought identified as key to severity of West Nile virus epidemics stat : stanford

Data from Colorado indicate that drought increases the fraction mosquitoes infected with West Nile virus, but not the abundance of mosquitoes. Yearly epidemicsWest Nile virus was introduced into North America in 1999 and has caused yearly epidemics each summer since. A study led by UC Santa Cruz researchers has found that drought dramatically increases the severity of West Nile virus epidemics in the United States, although populations affected by large outbreaks acquire immunity that limits the size of subsequent epidemics. They analyzed 15 years of data on human West Nile virus infections from across the United States and found that epidemics were much larger in drought years and in regions that had not suffered large epidemics in the past. "We found strong evidence that in some regions the spread of West Nile virus was indeed wave-like, with large outbreaks followed by fewer cases," Paull said.




While some people do get very sick from West Nile, many others who catch the virus show no symptoms, and any human that catches the virus is immune to future West Nile virus epidemics. Droughts bring a whole host of problems to humanity; limited water supplies, more wildfires, and the perfect conditions for a West Nile virus epidemic. Paull and colleagues also discovered that another key aspect of large West Nile virus outbreaks was human immunity. But if you do live somewhere where West Nile virus is prevalent, consider taking steps to protect yourself. So in areas that have already had large, drought-induced West Nile virus outbreaks, the number of people available to infect decreases dramatically, regardless of climate conditions.


Meanwhile, the Zika virus has joined West Nile virus as mosquito-borne diseases to defend against in San Diego County. Statewide, 436 Californians tested positive for West Nile virus in 2016 and 19 people died. In 2016, 22 county residents tested positive for West Nile virus and two died. A dead red-tailed hawk found in Valley Center has tested positive for West Nile virus, the first detection of the potentially deadly mosquito-borne disease in 2017 in San Diego County. Zika generated more headlines last year, but West Nile virus remains a threat.



collected by :Sandra Alex
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