West Nile Cases Are Rising. Here’s How to Protect Yourself

West Nile Cases Are Rising. Here’s How to Protect Yourself

By Meghan Bartels

West Nile disease starts with a mosquito bite—but when bad luck strikes, the infection can end with dire illness and even death.

West Nile virus is present throughout the U.S. Nearly all cases occur between July and October, and the first human infections and deaths of the year have already been reported. That isn’t cause to panic—but it is reason to take precautions against the virus.

“West Nile has become established in the U.S.,” says Gonzalo Vazquez-Prokopec, a disease ecologist at Emory University. “We have to live with West Nile.”

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The virus was first documented in the U.S. in 1999; its worst year to date came in 2003, when nearly 10,000 cases were reported. Since then infection levels have waxed and waned, likely as a result of climate factors and the species of birds that act as a reservoir for the virus, among other factors.

“In the beginning, 2002 and 2003 were really big years,” says Kristy O. Murray, an infectious disease specialist at Emory University. “We had another big outbreak year in 2012, and then I figure we’re kind of due for another one at this point.”

Whether 2024 will be a bad West Nile year is not yet clear. As of August 6, 103 human cases of the disease have been diagnosed in 26 different states this year. That’s lower than the 421 cases reported from January through July in 2023, but this year’s numbers are preliminary and may be influenced by reporting delays, making it difficult to draw conclusions. “West Nile virus tends to be unpredictable and varies from year to year, so we don’t know specifically how this year will be, compared to others,” says Erin Staples, a medical epidemiologist at the Centers for Disease Control and Prevention.

All told, just shy of 3,000 people in the U.S. have died of West Nile since 1999. But experts warn of the risks of underestimating the virus. Although most infections are asymptomatic, the virus triggers a fever in about 20 percent of people, and a small proportion of cases—about one in…