By Sue Tiffin

Published July 18 2017

No human or equine cases of West Nile virus have been reported in Ontario this year but the virus has been discovered in a batch of mosquitoes from Haliburton County.

According to the Haliburton Kawartha Pine Ridge District Health Unit mosquitoes collected in the county on July 6 tested positive for West Nile.

Residents are urged to take precautions such as wearing light-coloured long-sleeved clothing applying insect repellent and keeping areas near homes clear of standing water such as that in old tires or unused barrels.

Public Health Ontario conducts weekly surveillance using mosquito and human data from public health units and weather data from Environment Canada. In the 27th week of surveillance this year which took place from July 2 to 8 eight mosquito pools tested positive for West Nile virus. One pool each was also found in Halton Simcoe Muskoka and Windsor-Essex regions. Two positive pools were each found in Peel and Toronto regions. The positive pool found in the Haliburton County area is the first to be found locally this year but not the first to be found since 2002 when the province began monitoring for West Nile virus. West Nile virus has similarly been found in batches of mosquitoes previously and two crows tested positive for the virus in 2008.

Last year 211 mosquito pools in Ontario tested positive for West Nile virus. Fifty human cases were recorded in the province.

The virus confirmation is earlier than usual this year. The health unit advises taking precautions to protect against mosquitoes from spring until the first heavy frost.

“Typically West Nile virus confirmations occur later in the summer so this early finding confirms that we always need to be vigilant when protecting ourselves from illness caused by mosquitoes right from spring until the first heavy frost in the fall” said Richard Ovcharovich manager of environmental health with the HKPR District Health Unit in a press release. “We have seen evidence of other mosquito-borne illnesses in our area as well in recent years so it’s more important than ever to protect ourselves from the bite of mosquitoes.”

According to the health unit most people who contract West Nile virus do not exhibit any symptoms but some may experience headaches stiff necks and muscle weakness. In severe cases confusion and tremors can occur.

With files from Chad Ingram