First Mosquito Pool Tests Positive for West Nile Virus
August 15th, 2011
August 15, 2011
- Tests on mosquitoes taken from a trap located in the southwest part of Stratford have come back positive for West Nile virus (WNV). This is the first positive mosquito finding of the season in Perth County, and the first positive mosquito pool in Perth County since 2006.
"We are not surprised with this result because West Nile virus activity has been increasing in Ontario over the past few weeks,” says Dale Lyttle, Senior Public Health Inspector. So far in 2011, 43 WNV-positive mosquito pools have been found in Ontario. A mosquito pool is a group of female mosquitoes belonging to the same species.
As part of the Perth District Health Unit’s Vector-borne Disease Program, mosquito control activities are taking place across Perth County. A second round of larviciding has been completed in Stratford, St. Marys, Mitchell and Listowel. “Larviciding helps reduce the number of adult mosquitoes,” Lyttle explains.
Currently there are no human cases in Perth County or Ontario. The risk of humans getting sick with WNV is highest this time of year. Mosquitoes are usually active until the first hard frost. The Health Unit will continue to trap adult mosquitoes throughout Perth County until the middle of September.
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 get seriously ill, with symptoms like high fever, coma, muscle weakness and vision loss. People older than 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.
The Health Unit is asking residents to protect themselves from mosquito bites by:
- Using insect repellent when outdoors; a repellent with DEET offers the most effective protection.
- Covering up with light-colored 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.
- Removing standing water around the home at least once a week to reduce mosquito breeding grounds.
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