Middlesex-London Health Unit

What is West Nile Virus?
West Nile Virus (WNV) is a mosquito-borne virus initially recognized in West Nile, Uganda in 1937. WNV was first identified in the United States in 1999 and in Canada in 2001. Since then, NWV has spread across North America. Experts believe the virus is established as a seasonal epidemic, capable of affecting numerous individuals throughout the summer and early fall. This pamphlet contains important information that can help you identify the symptoms as well as reduce the risk of WNV.

How does WNV infect people?
WNV is spread to humans via the bite of an infected mosquito. Mosquitoes get the virus from feeding on infected birds. WNV can also be transmitted through a blood transfusion. To safeguard the blood system from WNV, Canadian Blood Services (CBS) implemented a new screening test for WNV. Since July 1, 2003 every unit of blood donated to CBS has been tested for WNV. Any unit of donated blood that tests positive for WNV is discarded, and the individual who makes the donation is deferred from donating again for 56 days, when the virus will no longer be present in their blood. There is also evidence that a woman infected during pregnancy may pass the virus onto her baby. Transmission is also possible through breastmilk. Although animals such as dogs, cats and horses can become infected with WNV, there is no evidence of transmission from animal to human.

What are the symptoms of West Nile Virus infection?
Most people infected with WNV will have no symptoms at all. Some people will experience mild illness such as fever, headache, muscle weakness, and body aches. These symptoms usually appear within 3-15 days after a person has been bitten by an infected mosquito. A few people will experience a more severe form of WNV infection called encephalitis (swelling of the brain). Symptoms of encephalitis include a rapid onset of severe headache, high fever, stiff neck, and disorientation. The elderly are at greater risk for developing the severe form of WNV. Many WNV patients experience long-term effects including fatigue, memory problems, muscle weakness and depression.

What is the treatment for West Nile Virus infection?
Currently there is no specific treatment for WNV infection. There are no vaccines available for use in humans. It is therefore, very important to protect yourself against mosquito bites in order to avoid WNV infection.

Although some mosquitoes are active during the day, take extra care when spending time outdoors between dusk and dawn when mosquitoes are most active. Avoid shaded areas where mosquitoes may be resting. You can protect yourself and your family from mosquito bites by:

• Choosing light coloured clothing and wearing pants, long sleeved shirts and socks.
• Using insect repellent containing DEET.
• 30% DEET will provide 6.5 hours of protection
• 15% DEET will provide 5 hours of protection
• 10% DEET will provide 3 hours of protection
• 5% DEET will provide 2 hours of protection
• Only apply DEET to exposed skin and avoid eyes and mouth. When applying DEET to the face, put DEET onto your hands first, and then apply to face. Never apply DEET to the hands or face of a child. If DEET gets into your eyes, immediately rinse with water.
• Wash off insect repellent when it is no longer required.
• Do not apply DEET to wounds or scratches.
• Do not spray DEET in enclosed areas such as cars or tents.
• Do not apply DEET under clothing (DEET may be applied to thin clothing to prevent mosquitoes biting through).
• Products containing plant-based oils such as citronella, lavender or lemon-grass provide less than one hour of protection against mosquito bites and are not recommended for children under 2 years of age.
• Do not use products that combine sunscreen and DEET. When applying sunscreen after insect repellent, additional sunscreen may be required.

How do I get rid of mosquito breeding areas near my home?
Mosquitoes require still water to lay their eggs. Reducing standing water significantly decreases the ability of mosquitoes to breed near your home!

To get rid of standing water:

• Regularly empty containers, unused flowerpots, garbage cans, etc.
• Inspect flat roofs for pooled water and unclog eaves troughs with regular cleaning.
• Ensure pool covers are drained of water and the pool's pump is circulating.
• Wading pools and wheelbarrows should be turned upside down when not in use.
• Ornamental pools and small ponds should be aerated or stocked with fish.
• Bird baths should be cleaned and emptied every other day.
• Ensure that openings in rain barrels are covered with mosquito screening or tightly sealed around the downspout.
• Remove all unused tires or debris that could collect water on your property. Drill holes in the bottom of tire swings.
• After a rainfall inspect your property for any areas of standing water.
• Fill in low depressions in lawn areas.

Do not allow grass clippings to enter roadside gutters or catch basins as they are a food source for mosquito larvae. Reduce areas where mosquitoes can rest by keeping lawns short and bushes trimmed. Keep screen doors and windows in good repair to avoid mosquitoes entering your home.

What can I do to help detect West Nile Virus?
Dead birds are often the first sign of West Nile Virus in a community. Crows and blue jays are more likely than other birds to die after being infected with WNV. If you locate a dead crow or blue jay, please call your local health unit (see below). Selected birds may be picked-up and tested for WNV. All dead crow and blue jay sightings will be recorded as part of a comprehensive WNV surveillance plan. Health units will also take reports of other dead birds, especially a large die-off.

REDUCE Mosquitoes
Mosquitoes breed in standing water. Be aware of problem areas around your home:

• Bird baths & ponds
• Wading pools, swimming pools & hot tubs
• Clogged eaves troughs & open rain barrels
• Containers that hold water like tires, toys & flower pot saucers
• Dripping faucets & garden hoses
• Areas that don't drain properly
• Holes in screens, windows and doors

• Avoid areas where mosquitoes are active
• Use insect repellent with DEET
• Cover up
• Wear light-coloured clothing

IMPORTANT INFORMATION FOR CHILDREN 12 YEARS OF AGE AND UNDER
DEET can be used in children 6 months of age and older according to the following instructions. In children 6 months of age to 12 years of age, DEET concentrations should not be greater than 10%. DEET should be applied sparingly. When applying repellent to children, rub the repellent on your own hands first, then apply it to the child. Do not apply DEET to the child's hands or face.

• For children 2-12 years of age, do not apply repellent more than 3 times per day.
• For children from 6 months to less than 2 years, the decision to use DEET should be considered in situations where a high risk of complications from mosquito bites exists. DEET should only be applied once daily.
• Do not apply DEET to children under the age of 6 months. When outside with a baby, cover the playpen or stroller with mosquito netting.
• Keep DEET products out of the reach of children.

Middlesex-London Health Unit
Dead Bird Reporting
by phone 663-5317, ext. 2300, press 2
online at www.healthunit.com and click on West Nile Virus
General Information
663-5317, ext. 2330
www.healthunit.com

Elgin-St. Thomas Health Unit
631-9900
www.elginhealth.on.ca

Oxford County Public Health & Emergency Services
539-9800, ext. 3483
new.county.oxford.on.ca