West Nile risk comes sooner than usual
A hot start to June could lead to earlier, heightened risk of the West Nile Virus this year in Minnesota.
Mosquito pools recently tested positive for the virus in the Twin Cities metro area, weeks before the virus-carrying bugs are typically found in early July.
Similar surveillance isn't performed in Southern Minnesota, but officials suspect the mosquito population elsewhere in the state could already be carrying the virus as well.
"Most of the time what we find is we're somewhat indicative of what we can expect for the rest of the state," said Kirk Johnson, vector ecologist with the Twin Cities-based Metropolitan Mosquito Control District. "I would expect mosquitoes are carrying West Nile Virus in most of southern Minnesota right now."
Minnesota Department of Health Epidemiologist Elizabeth Schiffman agreed, saying hot weather provided ideal conditions for mosquito development in late spring and early summer.
"It's reasonable to assume they're probably infected in other parts of the state," she said. " ... It's been a warm summer so far. It's kind of been a perfect storm for the development of these cycles."
It's not unprecedented for virus-carrying mosquitoes to be detected this early. It's just earlier than expected, meaning people should be aware of the risk as they spend more time outdoors, Schiffman said.
Just as early warmth can pull peak mosquito season closer, a cold stretch could push it back, Johnson said.
"If (a cool down) lasts three weeks or longer, it could really knock the virus down for most of the summer," he said.
Mankato's near-term forecast does project cooler temperatures, but expecting any cooldown to linger into July may be a bit much. Johnson recommended people statewide should already be protecting themselves against mosquito bites.
"It's really time to start thinking about the possibility of West Nile exposure, so protecting yourself against mosquito bites," he said.
Sleeves and long pants, while effective at limiting bites, can be a tough sell for people enjoying the few months of warmth the state offers. So spraying yourself with DEET repellent might be your best bet. Schiffman said dawn and dusk are the prime times for mosquito exposure.
Symptoms of West Nile include fever and headaches. Despite West Nile already being detected in mosquitoes, no humans have been infected in the state yet.