Health officials report three West Nile virus deaths; warn of mosquito-spread illnesses

(MADISON, Wis.) — Health officials are warning of the dangers of mosquitoes infected with West Nile virus after three recent deaths were recorded across Wisconsin and Illinois.

The Wisconsin Department of Health Services (DHS) confirmed on Thursday that two people have died and another was hospitalized due to the effects of the virus.

The cases were reported in Outagamie, Fond du Lac and Brown counties, according to the state’s DHS. Wisconsin officials did not release the identity of the individuals.

An average of 18 cases of illness from West Nile virus are reported in Wisconsin every year, according to DHS officials.

Earlier this week, health officials in Illinois announced the first death in the state from West Nile virus after a Lake County resident in their 80s had an onset of symptoms in mid-August and died soon after.

There were six West Nile virus deaths recorded in Illinois in 2023.

“Sadly, Illinois is reporting our first death of the year attributed to West Nile virus,” Illinois Department of Public Health director Dr. Sameer Vohra said in a statement Tuesday.

“This death — and the six that occurred last year in Illinois — are a stark reminder that West Nile virus poses a serious risk, especially to older people and those with weakened immune systems,” Vohra added.

What is West Nile virus?

West Nile virus is the leading cause of mosquito-borne disease in the continental United States, according to the Centers for Disease Control and Prevention.

There have been 289 human West Nile virus disease cases in 2024, according to the CDC.

Cases of the virus occur during mosquito season, which starts in the summer and continues through fall, according to the CDC. It was first introduced in the Western Hemisphere during the summer of 1999 after people were diagnosed in New York City.

Mosquitoes typically become infected with the virus after feeding on infected birds and then spread it to humans and other animals, the federal health agency said.

The majority of people with the virus do not have symptoms, but about one in five will experience fever along with headaches, body aches, joint pain, diarrhea, vomiting or a rash. Most symptoms disappear, but weakness and fatigue may last for weeks or months.

About one in 150 will develop severe disease leading to encephalitis, which is inflammation of the brain, or meningitis, which is inflammation of the membranes that surround the brain and spinal cord — both of which can lead to death.

To best protect yourself, the CDC suggests using insect repellant, wearing long-sleeved shirts and pants, treating clothing and gear and taking steps to control mosquitoes. This last step includes putting screens on windows and doors, using air conditioning and emptying out containers with still water.

Warnings of safety and awareness surrounding mosquito-spread illnesses are being heeded by health officials across the country.

On Tuesday, health officials in New Hampshire said a resident died from a rare but serious case of Eastern Equine Encephalitis virus, also called Triple E.

The patient was hospitalized due to severe central nervous system disease and died of their illness, according to the state’s Department of Health & Human Services (DHHS).

There have been cases reported in at least five states: Massachusetts, New Jersey, New Hampshire, Vermont and Wisconsin.

The U.S. averages 11 human cases of eastern equine encephalitis each year, according to the CDC.

Between 2003 and 2023, there have been at least 196 cases, including 176 hospitalizations and 79 deaths from EEE.

In Massachusetts, 10 communities were designated as being under high or critical risk of Triple E, according to the state’s Department of Public Health. Many of the areas began implementing targeted mosquito spraying to protect residents.

Similar to West Nile virus, Triple E can pose a significant health risk.

Symptoms can range from a febrile illness to more severe neurological problems, according to the CDC.

The disease is particularly dangerous if it leads to encephalitis, or inflammation in the brain, with approximately 30% of people with encephalitis dying.

Many survivors experience long-term neurological issues, according to the CDC, which notes there are no human vaccines or specific treatments available, making prevention crucial.