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More West Nile Positive Mosquitoes Found in Perth County

Wednesday, August 23rd, 2017

Perth County – Tests on mosquitoes taken from traps located in Mitchell and Listowel have come back positive for West Nile virus. This brings the number of positive mosquito pools to five in Perth County this season.

“We are not surprised with this result as West Nile Virus activity has been increasing in Ontario over the past few weeks,” says Dale Lyttle, Senior Public Health Inspector. So far in 2017, 172 West Nile Virus – positive mosquito pools have been found in Ontario. A mosquito pool is a group of female mosquitoes belonging to the same species.

The Perth District Health Unit has been trapping and testing mosquitoes since June and has applied two rounds of larvicide in roadside catch basins in Stratford, St. Marys, Listowel and Mitchell to help reduce mosquito breeding.

The risk of humans getting sick with West Nile Virus is highest this time of year. Currently, there are no human cases in Perth County. In Ontario, there have been eight reported (confirmed or probable) human West Nile Virus cases; two were travel-related.

Not everyone who is bitten by an infected mosquito will show symptoms. Of those who show symptoms, most will experience mild illness, including fever, headache, body ache, nausea, vomiting and/or rash on the chest, stomach or back. About one in 150 people infected will become seriously ill, with symptoms like high fever, muscle weakness, vision loss and coma. People over the age of 50 are most at risk for West Nile Virus infection, as are those with weakened immune systems. Symptoms typically develop between two and 15 days after being bitten by an infected mosquito.

Mosquitoes are usually active until the first hard frost. The Health Unit is asking residents to protect themselves from mosquito bites by:

  • Removing standing water around the home at least once a week to reduce mosquito breeding grounds.
  • Using insect repellent when outdoors; a repellent with N,N-Diethyl-meta-Toluamide (DEET) or Icaridin offers the most effective protection.
  • Covering up with light-coloured clothes, long sleeves and pants when outdoors or while in areas where mosquito activity is high.
  • Taking extra protection measures at dusk and dawn when mosquitoes are most active.

For more information:

  • Call Health Line at 519-271-7600 or toll-free at 1-877-271-7348 extension 267
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