Mosquito-borne West Nile virus on the rise in Minnesota

The Minnesota Department of Health has confirmed 20 cases of West Nile Virus so far this year. Of those 20 cases, two people have died.

Citing the recent increase, health officials urge Minnesotans to take precautions.

West Nile virus is transmitted to people through the bite of an infected mosquito. Annual cases can vary widely depending on heat and rainfall. Less than 1% of people bitten by an infected mosquito develop encephalitis or meningitis — inflammation of the brain or surrounding tissues — and symptoms usually show up within one to two weeks. West Nile virus disease has no treatment other than supportive care.

Elderly patients and those with weakened immune systems are at greatest risk for severe disease, followed by people who work outside or participate in outdoor activities.

The highest risk areas for West Nile include the agricultural regions of western and central Minnesota, but cases of West Nile virus disease have been found throughout the state.

“This is a high-risk time of year for West Nile virus transmission,” stated Elizabeth Schiffman, supervisor of MDH’s Vectorborne Diseases Unit, in a news release.

“It’s important to prevent mosquito bites when people are enjoying time outside while the weather is still nice. That’s the best way to avoid getting West Nile virus.”

MDH issued the following precautions against mosquito bites:

• Use insect repellents that are registered by the Environmental Protection Agency and contain up to 30% DEET  
• Pretreat clothing and gear with permethrin-based products
• Wear loose-fitting, long-sleeved shirts and pants 
• Be extra cautious or avoid outdoor activities at dusk and dawn, the peak feeding time for many mosquitoes, particularly from July through September
• Keep mosquitoes out of your home by maintaining screens on windows and doors