May 17, 2007 (DISTRICT OF THUNDER BAY) - The West Nile Virus surveillance season starts on Tuesday, May 22, 2007, with the activation of the Thunder Bay District Health Unit’s “Crow Line.”

The Crow Line will be accepting calls from district residents who wish to report any dead crows, ravens or blue jays in their area. These species are highly susceptible to West Nile Virus and are therefore used to signal the prevalence of the disease. New this year, residents are asked to report three or more dead birds of the same species found in close proximity.

If a bird or birds of these descriptions are found, the public is urged to call the Thunder Bay District Health Unit at 625-8328 (City) or toll-free 1-866-582-9003 (District of Thunder Bay).

If the bird did not die from injury or trauma, dead birds may be collected for West Nile Virus testing. Last year, 152 calls to the Crow Line resulted in 32 birds submitted for testing with twelve birds testing positive for the virus.

As part of the surveillance program, Dr. Ken Deacon, Bioconsultant for the Thunder Bay District Health Unit, also conducts mosquito trapping and species analysis. Deacon explains, “The presence of West Nile Virus in the bird community may lead to the disease being transmitted to mosquitoes and from mosquitoes to humans. By monitoring mosquito populations, we can assess the risk to the human population.”

According to Deacon’s Study, the overall risk to human health in the Thunder Bay District was considered minimal. “Only 0.8% of the mosquitoes were the species (Culex restuans) which are able to transmit the disease to birds. Also of interest is that the number of mosquitoes trapped was down by over half from two years ago, indicating a significant drop in population even though trapping efforts were increased,” said Deacon.

Last year, there were no human cases of West Nile Virus reported in the Thunder Bay District; however there was one within the Northwestern District.

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A complete study of the 2006 data will be posted on the Thunder Bay District Health Unit’s website www.tbdhu.com/EH/WestNile/.

For more information,
Laura J. Craig 
Coordinator, Marketing and Communications 
Phone: (807) 625-8800