August 12, 2024
3 Minimum read time
Cases of West Nile disease are on the rise. Here’s how to protect yourself.
Western Nile fever is the most common mosquito-borne disease in the United States. Here’s what you need to know about this infection.
Western Nile fever begins with a mosquito bite, but if you’re unlucky enough, the infection can lead to severe illness or even death.
West Nile virus is present throughout the United States. Almost all cases occur between July and October. First human infection and dead Cases have already been reported this year. It is not a reason to panic, but it is a reason to take precautions against the virus.
“The West Nile is here,” says Gonzalo Vázquez-Prokopek, a disease ecologist at Emory University. “We have to live with it.”
About supporting science journalism
If you enjoyed this article, please support our award-winning journalism. Subscriptions. By purchasing a subscription, you help ensure a future of influential stories about the discoveries and ideas that shape our world today.
The virus was first reported in the United States in 1999. The worst year so far was 2003, when about 10,000 cases were reported. Since then, infection levels have risen and fallen, likely due to a number of factors, including climate factors and bird species that act as reservoirs for the virus.
“The first two were really big years, 2002 and 2003,” says Christy O. Murray, an infectious disease specialist at Emory University. “We had another big outbreak in 2012, and now it looks like we’re going to have another one.”
It’s not yet clear whether 2024 will be a bad year for West Nile virus. As of August 6, 103 human cases of West Nile virus infection have been diagnosed in 26 states this year. That’s fewer than the 421 cases reported from January to July 2023, but this year’s numbers are preliminary and subject to reporting delays, making it difficult to draw any conclusions. “We don’t know specifically how this year will compare to other years because West Nile virus is unpredictable and changes from year to year,” says Erin Staples, a medical epidemiologist with the CDC.
In the United States, just under 3,000 people have died from West Nile fever since 1999. But experts warn of the dangers of underestimating the virus. Most infections are asymptomatic, but the virus causes fever in about 20% of people, and a small number of cases (about 1 in 150) are what doctors call “neuroinvasive,” reaching the brain, causing encephalitis, or the spinal cord, causing meningitis.
In either scenario, neuroinvasive encephalitis can have serious consequences. People can develop a stiff neck and massive headaches. “They’ll say it’s the worst headache they’ve ever had in their life,” Murray says. And because there is no specific treatment for the condition, doctors can only treat the symptoms and hope for the best. Many people with neuroinvasive infections never fully recover. “About 40 percent of our meningitis cases never return to baseline, and for encephalitis cases, [that figure] “It was 80 percent,” Murray said.
Scientists don’t know what determines how severe a West Nile infection is. “Most people don’t get neuroinvasive disease,” says Robin S. Klein, a neuroimmunologist and physician at Western University in Ontario. Older people and people with weakened immune systems appear to be more likely to develop more severe cases of West Nile, but young, healthy people can still get sick. “It’s not clear exactly why some people get invasive disease,” she adds.
There is currently no approved vaccine for West Nile virus. Several candidates have shown promising results in early testing, but efforts have been slowed by lack of profit incentives. And the virus will never go away, as it is transmitted by several different mosquito species and primarily infects birds, which, unlike humans, cannot follow public health guidelines.
The only sure way to avoid this disease is to avoid being bitten by mosquitoes that carry the virus. The West Nile is the most common mosquito in the genus Mosquitoes. Coolex, Other types can carry it too. And Coolex Mosquitoes love to spend time around people and bacteria-rich environments, says Vazquez-Prokopec. “They’re the cockroach of mosquitoes,” he adds. “They’ve actually evolved and adapted to bite people and live in urban areas.”
Local governments often try to kill mosquitoes with pesticides or habitat removal, but Murray warns people not to rely solely on these efforts to stay safe from the West Nile. “We’re doing our best to reduce the population, but it’s not a perfect science,” Murray says. “It’s always a challenge.”
These insects bite most at night, so people living there Coolex Because mosquitoes are so common, extra precautions should be taken against them during that time. In particular, Vazquez-Prokopec recommends wearing long sleeves and pants, using CDC-approved repellents to reduce bites, and getting used to taking mosquito hazards seriously. “The future of urban living in America is, in some ways, a future with more bugs,” he says.
