Tests on mosquitoes taken from a trap located in the northern part of Stratford have come back positive for West Nile virus (WNV).
This is the second positive mosquito finding of the season in Perth County.
“We are not surprised with this result because West Nile virus activity has been increasing in Ontario over the past few weeks,” says Stephanie Carlisle, public health inspector.
So far in 2013, 41 WNV-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 WNV is highest this time of year. Currently there are no human cases in Perth County. In Ontario, there are two probable/confirmed human cases of WNV.
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 rash on chest, stomach or back. About one in 150 people infected will become seriously ill, with symptoms like high fever, coma, muscle weakness and vision loss.
People over the age of 50 are most at risk for WNV infection, as are those with weakened immune systems. Symptoms usually develop between two and 15 days after being bitten by an infected mosquito.