Control of mosquito larvae set to begin

Catch-basin larviciding, which helps control mosquito larvae, is beginning in Perth County as part of the Perth District Health Unit’s West Nile virus prevention plan.

Recent data shows that mosquito larvae populations are increasing in catch basins – also known as roadside storm sewers – in Stratford, Mitchell and Listowel, states a PDHU press release. The catch basins will be treated to help reduce the incidence of West Nile virus in Perth County.

“Municipal catch basins are a primary breeding area for the type of mosquito that carries the virus in Ontario”, says Virginia Kelly, public health inspector. “Larval-control measures help stop the immature mosquito from growing into an adult mosquito. It is the adult mosquitoes that can transmit the virus to humans.”

Larviciding is conducted in a community when 50% per cent of the catch basins show a population density of mosquito larvae that is moderate to high.

“We are now seeing this amount of activity inside some of our catch basins in Stratford, Mitchell and Listowel,” says Kelly. “We will continue to monitor the catch basins in other communities such as St. Marys and Milverton.”

The larvicide comes in small pellets of Altosid or pouches of Vectolex, which are dropped directly into the sewers. The Health Unit has contracted The Canadian Centre for Mosquito Management to treat the catch basins.

As the summer goes on, the risk of WNV increases. To stop WNV from spreading in Perth County, residents are advised to:

• Clean up standing water around the home once a week. Drain areas such as old tires, kids’ toys and wheelbarrows, and frequently change water in birdbaths.

• Apply insect repellent when outdoors. A repellent with DEET offers the most effective protection. Always follow the manufacturer’s instructions.

• Cover up with light-coloured clothing when outdoors, such as long sleeves, pants and socks.

• Take extra protection measures between dusk and dawn when mosquitoes are most active.

• Call Health Line at 519-271-7600 ext 267 to report a dead crow or blue jay.

The Health Unit is also trapping adult mosquitoes. Traps are hung at specific spots across the county. The mosquitoes that are caught are sent for testing. No adult mosquitoes have tested positive for WNV in Perth County yet this year.

In Ontario, dead crows and blue jays are starting to test positive for WNV. This year, three birds have tested positive for WNV in Ontario, although there have been no positive birds in Perth County. The first and only positive mosquito pool so far was found in Windsor-Essex.

For more information, call Health Line at 519-271-7600 ext 267 or visit www.pdhu.on.ca.