Health Department warns St. Joseph County residents of increased West Nile Virus risk

The St. Joseph County Department of Health instructed residents to be mindful of the threat of the mosquito-borne West Nile Virus, despite cooling temperatures.

According to a news release from the department Friday afternoon, mosquitoes are still being trapped and are increasingly testing positive for the virus.

"Based on the results of the samples that are being submitted, the infection rates within those pools of mosquitoes that are coming back positive are getting high enough where there's an increased risk for humans to get West Nile," said Brett Davis, St. Joseph County assistant director of environmental health, who traps and tests mosquitoes for the virus.

The St. Joseph County Department of Health is urging residents to take precautions to protect themselves against the mosquito-borne West Nile Virus.
The St. Joseph County Department of Health is urging residents to take precautions to protect themselves against the mosquito-borne West Nile Virus.

So far this year, 24 pools of mosquitoes testing positive for West Nile Virus have been identified in the county. Additional positive pools are expected to be identified this year because mosquitoes are still being trapped and tested, Davis said.

In neighboring Elkhart County, a record 20 pools of virus-positive mosquitoes have been identified this year, according to the release.

Last year in St. Joseph County, Davis said, 22 pools of virus-positive mosquitoes were identified, a number that has already been surpassed this year.

"We still have results coming in, and I still have to test mosquitoes I've collected this week," he said. "The infection rate is elevated. It's not all that dissimilar to last year, but we still have data coming in."

Be vigilant: West Nile Virus detected in St. Joseph and Elkhart counties in August

Although no human cases of West Nile Virus have been reported in St. Joseph County this year, two cases have been reported in other Indiana counties. In October 2021, one St. Joseph County resident contracted the virus.

According to the Department of Health, the threat of West Nile Virus will persist until a "hard freeze." Davis defined a hard freeze as at least a few consecutive hours of sub-20-degree temperatures.

Symptoms of West Nile Virus usually appear 2-14 days after a bite from an infected mosquito. Possible symptoms include headaches, body aches, joint pain, vomiting, diarrhea and rashes.

Most people who contract West Nile Virus recover quickly, but some have persistent fatigue and weakness, the release said. The Department of Health recommends contacting your healthcare provider if you believe you've contracted West Nile Virus.

How can I protect myself against West Nile Virus?

In the release, the Department of Health recommended residents take the following steps to protect themselves and their families from mosquitoes and West Nile Virus infections:

  • Avoid being outdoors during prime mosquito biting times ― dusk to dawn ― when possible.

  • Apply an EPA-registered insect repellent containing DEET, picaridin, IR3535, lemon eucalyptus oil or para-methane-diol to clothes and exposed skin.

  • Cover exposed skin by wearing a hat, long sleeves and long pants in places where mosquitos are especially active, such as wooded areas.

  • Treat clothing and outdoor gear with 0.5% permethrin if camping or spending extended periods of time outdoors.

  • Make sure all windows and doors have screens and that all screens are in good repair.

  • Reduce mosquito breeding on and around your property.

"I would really hammer home, at this point, that residents need to wear insect repellent, especially insect repellent that has the CDC-approved active ingredients," Davis said. "Being that it is cooler, people are wearing more pants, long-sleeve shirts and hats, which is great, but you'll still have exposed skin around your ankles, your hands, neck, that sort of thing. Especially if you're going to high school football games or sitting around bonfires, you're still going to be out and exposed to those mosquitoes. Make sure you wear your insect repellent."

Email Tribune staff writer Claire Reid at

This article originally appeared on South Bend Tribune: St. Joseph County's West Nile Virus risk on the rise: officials