August 09, 2002

West Nile Virus positive mosquito pool identified in York Region

NEWMARKET York Region Health Services advises that a West Nile Virus (WNV) positive mosquito pool has been identified in the Regional Municipality of York. Located in the Town of Markham near the intersection of Leslie Street and Steeles Avenue, this is the first WNV positive mosquito pool in the Region.

Health Canada officials from the Zoonotic Diseases and Special Pathogens section of the National Microbiology Laboratory in Winnipeg confirmed the positive pool of mosquitoes collected last month between July 10th and July 23rd.

"We are not alarmed with the identification of the positive mosquito pool and it is not unexpected," said Dr. Hanif Kassam, Director, Public Health Programs and Associate Medical Officer of Health. "There are no human cases of West Nile Virus in Canada, while five positive pools have already been identified in the Regional Municipality of Peel. York Region Health Services continues to monitor the West Nile Virus situation throughout the Region."

Two birds in York Region have tested positive for WNV this year. During the 2001 season, 25 birds tested positive for WNV in the Region, including 20 birds in Markham, three in Vaughan, one in Whitchurch-Stouffville and one in Georgina.

West Nile Virus is a viral disease that can be spread to the human population by mosquitoes, which contract the disease after biting an infected bird. The WNV can cause illness in humans, especially the elderly and immune compromised population.

Humans cannot get the virus from another person, animal or bird. Illnesses related to mosquito bites and WNV are, in fact, very rare. Health Canada states that in exposed areas, less than 1% of the mosquito population is likely to carry the virus.

In the majority of people, exposure will result in minimal or no symptoms. A very few may develop mild flu-like symptoms or a rash. In more serious cases (less than 1 per cent of all infected individuals), encephalitis (inflammation of the brain) can occur, causing severe muscle weakness, headache, stiff neck, vomiting, nausea and eventual deterioration of consciousness or mental state.

York Region Health Services reminds residents to continue to report sightings of dead crows to the Health Protection Division. These birds are known to be the most susceptible to the disease.

Residents are also reminded that, although the risk of coming into contact with the WNV is minimal, there are precautions that can be taken:

Personal Protection

Around the Home

For more information or to report a dead crow, please call York Region Health Services Health Connection at 1-800-361-5653.

For ongoing, up-to-date West Nile Virus reports, precautions and information, residents are invited to refer to the West Nile Virus Update on the York Region website at or call 1-800-361-5653.

For more information on the Regional Municipality of York, the services we offer and links to our nine area municipalities, please visit our Web site at

The Regional Municipality of York is committed to providing cost-effective, quality services that respond to the needs of our rapidly growing communities.  York Region is comprised of the following nine area municipalities:  Aurora, East Gwillimbury, Georgina, King, Markham, Newmarket, Richmond Hill, Vaughan and Whitchurch-Stouffville.  For more information, visit our Web site at:

Contact: Patrick Casey, Senior Media Relations Specialist, York Region

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