A locally acquired case of West Nile virus - identified in a horse in Bruce County - reinforces the message that residents and visitors need to take precautions against mosquito bites.
Tests on mosquitoes taken from a trap in the northeastern part of Stratford have come back positive for West Nile virus. This brings the number of positive mosquito pools to six in Perth County this season.
The Perth District Health Unit has been trapping and testing mosquitoes in Stratford, St. Marys, Listowel and Mitchell since June.
The Huron County Health Unit says two samples from mosquito traps around the county tested positive for the virus.
Surveillance traps in Owen Sound, Hanover and the Town of the Blue Mountains have detected mosquito species that can be carriers of the virus, but none of the mosquitoes trapped to date in Grey-Bruce were found to be carriers.
The risk of people getting sick with WNV is highest this time of year. There have been 14 reported human WNV cases in Ontario this year -- two were travel-related.
Mosquitoes are usually active until the first hard frost.
The risk of exposure to the virus around the home can be reduced by eliminating mosquito breeding sites, including standing water in places such as bird baths, eavestroughs, flower pots and discarded tires; by wearing protective clothing; always using mosquito repellent when outdoors at dawn and dusk; and by preventing mosquito entry into the home.
So far in 2017, 264 West Nile-positive mosquito pools have been found in Ontario.
The virus is transmitted through the bite of an infected mosquito. Symptoms usually develop two to 14 days after receiving a bite from an infected mosquito.
About 80% of those infected with West Nile do not show any symptoms. Of the 20% that do show symptoms, most experience mild illness with symptoms such as fever, headache, body aches, fatigue, skin rash and occasionally, vomiting and nausea. Less than 1% of those infected with the virus experience severe illness involving the central nervous system.
Mosquito trap (photo submitted by Grey-Bruce Health Unit)
