West Nile virus cases increase nationwide during mosquito season

June 19, 2023 – State and local health authorities across the country are reporting the first human cases of West Nile virus of the season and are urging people to take steps to protect themselves from the mosquito-borne disease.

Over the past 2 weeks, new cases have been reported in Iowa And Nebraska, adding to previous 2023 reports from Arizona, Georgia, Illinois, Louisiana, Oregon, Pennsylvania and Wyoming. A mosquito at a surveillance site near Houston tested positive for the potentially deadly virus last week, prompting local health officials to begin evening spraying operations in the area where the mosquito was found, according to a announcement of Harris County Public Health.

According to CDCwhich compiles local reports, there were 13 human cases of West Nile virus in 2023. In 2022, there were 1,126 cases, including 90 deaths.

Of the 13 cases reported this year to the CDC so far, eight people add severe neuroinvasive disease, meaning the disease has spread to the nervous system. These serious symptoms usually occur in 1 in 150 West Nile virus cases and can include encephalitis, which is inflammation of the brain, or meningitis, which is inflammation of the membranes that surround the brain and spinal cord. Three of the neuroinvasive cases occurred earlier this year amid an outbreak in Maricopa County, AZ, where the disease is considered endemic, according to an April 28 report. report from the CDC.

The CDC says West Nile virus is the most common disease spread by mosquitoes in the continental United States. Local health officials sample mosquitoes to guide mosquito control strategies. So far this year, the CDC has received 28 reports of mosquitoes testing positive. These mosquito test reports came from Arizona, California, Florida, Indiana, Louisiana and Texas.

West Nile virus is transmitted to humans through the bite of an infected mosquito, but it can also be transmitted to humans if they handle an infected dead bird. The CDC says there are no drugs to treat the virus in humans. Most infected people do not feel sick and 1 in 5 infected people develop fever and other symptoms such as headache, body aches or a rash.

Prevention strategies include wearing insect repellent and wearing long-sleeved shirts and long pants to avoid mosquito bites.