Mosquitoes bring the West Nile virus back to Minnesota

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The humid weather is back, the mosquitoes are back, and now in Minnesota – the West Nile virus is back.

The Metropolitan Mosquito Control District (MMCD)says a sample of mosquitoes in Ramsey County tested positive for the virus this past week, becoming the first positive test result of the year.

No human cases of the potentially life-threatening virus have been reported in the state so far, but the MMCD said in a news release that the recent heavy rain coupled with the warming summer temperatures means it expects to see mosquitoes spread the virus within the state's bird population.

"West Nile virus is usually detected in mosquito samples around this time of year, and it will continue to circulate among mosquitoes and birds," MMCD ecologist Kirk Johnson said in the release. "Even though the health risk is still low, we should all use common sense measures to avoid mosquito bites."

The return of the virus – which causes flu-like symptoms and can in very rare cases be fatal – happened at a similar time as last year.

However, the first confirmed human case of the virus didn't come in Minnesota until early August, later than usual.

In 2013, Minnesota Department of Health (MDH) figures show that there were 79 human cases of the virus across 39 counties, which resulted in three deaths.

How does it affect humans?

The MDH says most people infected with the virus won't notice any symptoms at all, but about one in five people will develop symptoms of West Nile fever, which can include a high fever, severe headache, nausea, vomiting, sore throat, a rash, swollen lymph nodes, backache and joint pain.

Around one in 150 people will develop West Nile encephalitis, a more severe neurological disorder that causes inflammation of the brain. The Centers for Disease Control and Prevention (CDC) says 10 percent of people who get West Nile encephalitis die.

The MMCD is asking people to report any dead birds that they see (the West Nile virus can be fatal to certain species of birds) to help them track the virus' spread across the state.

They also suggest people reduce their exposure to mosquitoes by:

  • Clearing water-holding containers in yards or neighborhoods (where mosquitoes can develop).
  • Ensuring window screens are in good repair.
  • Wearing long-sleeved, loose-fitting, light-colored clothing.
  • Using bug spray.
  • Avoiding prolonged outdoor activity at dawn and dusk – when mosquitoes are at their most active.

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