West Nile virus is responsible for hundreds of deaths in the United States each year, and now scientists are worried that mosquitoes carrying the virus — and others — are becoming harder to kill.
Scientists with the Centers for Disease Control and Prevention say mosquitoes in lab studies are becoming increasingly resistant to common insecticides and staying alive longer, according to a report from NBC News. And as the bugs grow stronger, they're also becoming more prevalent in certain communities across the nation.
There have been at least 90 cases of West Nile virus in humans in the U.S. so far this year, according to CDC data. While that's nowhere near the 9,862 cases reported in 2003, the highest ever recorded in a year, the virus is still rampant two decades later.
In Arizona's Maricopa County, nearly 150 mosquito traps have tested positive for West Nile virus so far this year, compared to just eight in 2022. Now scientists worry that outbreaks of the virus may increase as heavy rains and extreme heat continues to sweep across much of the U.S.
"If we keep experiencing more storms, more water, more accumulation of water and that water remains stagnant for around three to five days, that would be conducive to mosquito breeding, especially as we get warm temperatures," said Johnny Dilone, Maricopa County Environmental Services community relations manager.
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While the chances of a person actually contracting West Nile virus are low, it's not a chance one should take.
Humans can contract it when bitten by infected mosquitoes, which get it from feeding on infected birds. Most people infected with West Nile virus experience no symptoms — or mild flu-like symptoms — but the virus can cause severe illness and, in some cases, death.
The blood sucking bugs can also carry other diseases like Malaria, Zika virus, and Jamestown Canyon virus. Though the first two are most commonly found in tropical and subtropical areas like Africa and South America, Jamestown Canyon virus is most prevalent in the upper Midwest of the United States.
While not typically fatal, the U.S. has reported more than 281 cases of Jamestown Canyon virus since 2011, including at least seven deaths.
To date, there are no vaccines to prevent or medicines to treat those infected with West Nile virus or Jamestown Canyon virus, meaning people can only reduce their risk of infection by preventing mosquito bites.
Across the U.S., preventing the bugs from breeding is also top of mind for health officials. That in part relies on keeping the bugs away by spraying insecticides. But if mosquitoes are continually growing more resistant to these chemicals, the U.S. faces the potential for another massive outbreak of viral infections like the one seen in 2003.
