August 23, 2007 (THUNDER BAY & DISTRICT) - The Thunder Bay District Health Unit has confirmed an asymptomatic human case of West Nile virus. The Canadian Blood Services identified the virus through routine screening carried out on a blood donation. The individual is not ill. It appears that the virus was acquired in this area.

“Typically, those infected with the virus show no symptoms,” states Dr. Nancy Cameron, Medical Officer of Health. “However, the infection can present mild, flu-like symptoms known as West Nile fever.” Only on rare occasions does a West Nile virus infection result in serious neurological illness, such as encephalitis (inflammation of the brain).

West Nile virus is transmitted to people through the bite of an infected mosquito. Mosquitoes acquire the virus after feeding from the blood of infected birds.

“The risk of infection among the general public is very low because less than three per cent of the mosquitoes in the district are the species that are able to carry the virus to birds,” said Dr. Ken Deacon, entomologist.

Mosquito surveillance undertaken by the Health Unit has not provided evidence of increased risk. In addition, from now to freeze-up, mosquitoes have stopped feeding on birds. When birds are no longer being infected, the risk of infection to humans decreases dramatically.

Although the risk of West Nile infection in the District is low, to avoid mosquito bites and the risk of West Nile virus infection, the Thunder Bay District Health Unit recommends the following:

1. Use insect repellant with DEET or other approved ingredients.
2. Wear long-sleeved shirts, long pants and hat.
3. Wear light coloured clothing.
4. Ensure that door and window screens fit tightly.
5. Eliminate standing water, especially in containers like rain barrels, buckets, or tires around homes and vacation property.

For information on West Nile virus and surveillance by the Thunder Bay District Health Unit visit: www.tbdhu.com/EH/WestNile

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For more information
Laura J. Craig
Coordinator of Marketing and Communications
Thunder Bay District Health Unit
(807) 625-8800