York Region reports first presumed positive West Nile Virus bird

Newmarket: York Region Acting Medical Officer of Health, Dr. Hanif Kassam, advises that a dead crow has been tested and is presumed positive for West Nile virus (WNv ). The dead crow was found in the Town of Newmarket, close to the intersection of Leslie Street and Mulock Drive. The bird is the first presumed positive bird reported in York Region and in Canada.

"We anticipated West Nile virus activity this year," said Dr. Hanif Kassam, Acting Commissioner of York Region Health Services and Medical Officer of Health. "Knowing where that activity might be allows us to take appropriate action to monitor and prevent the spread of West Nile Virus in our community. This information puts our plan in action."

"I remind residents to report dead crows to our Health Connection information line," he added. "Crows are known to be most susceptible to the disease and act as an early warning system for the presence of the virus in a particular area. The more information we have the faster and more effectively we can respond."

The York Region WNv control plan for 2003 includes:

• Extensive public education regarding effective measures to prevent exposure to WNv, including brochures, posters, transit advertising, public information sessions and community outreach activities

• Mosquito, bird and human surveillance
• WNv control activities, including a larviciding strategy in three phases

• May - The first application will target the catch basins in the identified WNv "hot spot" areas where positive human, bird and mosquito cases were found in 2002
• June and July - The second and third applications will target all catch basins in Richmond Hill, Vaughan, Markham, Newmarket, Aurora, Keswick, Holland Landing and other urban areas with catch basins, including the "hot spots"

• In addition, newly identified positive bird, mosquito and human cases in 2003 will be mapped and larvicide applied in the catch basins around those newly detected positives
• Larviciding is a safe and effective measure for the control of WNv. Methoprene is the larvicide that will be used. It comes in slow-release pellet-like formulations and is administered when the mosquito is in the larval stage of development. It has been approved by both the provincial and federal governments and is considered safe for humans and the environment
• Storm water retention ponds and large bodies of water on municipal and Regional property will be included in the mosquito surveillance program. If WNv is detected, larviciding will be considered.
• Residents in the targeted areas will be notified 48 hours prior to larviciding activities.

West Nile virus is a mosquito-borne virus that can cause encephalitis (inflammation of the brain) or meningitis (inflammation of the lining of the brain and spinal cord). The virus is named after the West Nile region of Uganda where it was first isolated in 1937.

WNv was isolated in the human, bird, equine (horse) and mosquito populations in York Region during the 2002 season. York Region reported 6 confirmed and 4 probable human cases of WNv in 2002. The Ministry of Health and Long-Term Care attributed 17 deaths in the province last year to WNv illness.

WNv is transmitted by infected mosquitoes. In humans, it takes about 3 to 15 days after a bite from an infected mosquito for flu-like symptoms to begin. Most people infected will have no symptoms or very mild illness. Symptoms range from mild fever and headache to loss of consciousness, seizures, weakness on one side of the body and swelling of the brain resulting in brain damage.

WNv is transmitted to the bird population in the same manner. Symptoms in birds manifest as neurological signs such as convulsions, tremors, head tilt, wing droop and paralysis.

York Region Health Services asks residents to report dead crows, with suitable specimens collected and submitted to the Canadian Co-operative Wildlife Health Centre in Guelph for screening. All crows that are reported will help to map out possible West Nile virus activity in York Region.

Dead crows are to be reported to York Region Health Services through the Health Connection information line. Location details will be recorded, for mapping purposes, with the following direction:

• Suitable specimens will be collected by York Region Health Services and sent for testing. A suitable specimen must be a crow and must have been dead less than 12 hours
• Unsuitable specimens should be disposed of by the resident. Do not dispose of dead birds through municipal garbage systems. Unsuitable bird specimens must be double bagged and disposed of or buried under at least 2 feet of soil. Use rubber gloves and a shovel to handle the carcass. Do not handle birds with bare hands.

Prevention and protection are the best ways to protect yourself from WNv. There are simple and common sense precautions that should be taken:

• Wear protective clothing such as long sleeved shirts, full-length trousers, socks, light coloured clothing and high boots

• Use a repellent containing DEET, as directed
• Minimize outdoor activities where and when mosquitoes are most active such as dusk, night and dawn
• Make sure screens on your home are tight-fitting and in good repair
• Mosquitoes breed in still water. Eliminate standing water around your property which may gather in pool covers, flower pots, children’s pools, old tires and birdbaths

Media Briefing:

Dr. Hanif Kassam will speak to the media about this issue on

Monday, April 28 at 11:40 a.m.

The Great Hall, York Region Administrative Centre

17250 Yonge Street, Newmarket

Contact: Kim Clark, York Region Health Services

905-830-4444 ext. 4101