WNV and EEEV Surveillance
Due to the arrival of cooler temperatures, surveillance has completed for the 2012 season. The prevention and control program will resume again in the Spring of 2013.
Confirmed cases of WNV in the human population of Ottawa: 8
Confirmed cases of EEEV in the human population of Ottawa: 0
To resume in the Spring of 2013
Application of larvicide
To resume in the Spring of 2013
West Nile Virus
West Nile Virus (WNV) is an infection spread my mosquitoes that - in a small number of cases - can cause serious illness.
- Mosquitoes, especially those from the Culex genus, become infected after biting a bird with the virus. WNV is originally a bird virus and the most infected species are corvids: ravens, crows and blue jays.
- The virus is spread when an infected mosquito bites a reptile, amphibian or mammal, including humans.
- Most people will show no symptoms if infected with WNV, but in some individuals - particularly the elderly or those with weakened immune systems - they may experience:
- Flu-like symptoms, including, but not limited to, fever, frontal headache, muscle aches and occasionally a skin rash;
- Additional symptoms may include neck stiffness, muscle weakness, stupor, disorientation and coma.
- It can take between three and 15 days before symptoms occur.
Eastern Equine Encephalitis Virus
- Eastern Equine Encephalitis (EEEV) is a very rare, but serious, virus that has rendered one third of all those infected in coma and/or death. A greater number of cases have resulted in permanent mental and physical disabilities.
- Similar to WNV, EEEV is spread by mosquitoes after feeding on birds infected with the virus.
- The virus is most often identified in mosquitoes which inhabit hardwood swamps and bogs in rural and suburban areas.
- Humans and several other types of mammals, particularly horses and lamas, can become infected, however they do not spread the disease.
- There has never been a reported human case of EEEV in Ontario, however detection in mosquitoes and horses in 2009 signified the need for enhanced provincial surveillance.
- The first symptoms of EEEV are high fever, stiff neck, headache, and lack of energy. These symptoms appear three to ten days after a bite from an infected mosquito. Encephalitis – the inflammation and swelling of the brain - is the most dangerous and frequent complication associated with the virus. The disease gets worse quickly and some patients may go into a coma within a week.
How to protect yourself from mosquito bites
Reduce your chance of infection from vector borne illness by doing the following:
- Apply an approved mosquito repellent to exposed skin and clothing.
- Wear long pants, a long-sleeved shirt, shoes and socks to protect exposed skin.
- Wear light coloured, tightly woven clothing - mosquitoes are attracted to darker colours and can still bite through thin clothing.
- Avoid wearing scented perfumes, deodorants and personal products.
- Avoid the hours between dusk and dawn - periods when mosquitoes are most active.
- Make sure all windows and doors in your home have screens that are in good condition.
Eliminate standing water sites around your home
Mosquitoes are attracted to, and breed, in water. Help eliminate nuisance mosquitoes around your property by reducing or eliminating areas or objects which can accumulate or retain water.
Here are some suggestions:
- Look around/outside your house for containers, receptacles and any other items that might collect water. Be sure to empty them regularly, turn them over when appropriate, or dispose of them accordingly.
- Drill holes in the bottom of recycling containers that are left outdoors so that water can drain out.
- Clean clogged roof gutters; remove leaves and debris that may prevent drainage of rainwater.
- Turn over plastic wading pools and wheelbarrows when not in use.
- Change the water in birdbaths every few days; aerate ornamental ponds or stock them with fish.
- Keep swimming pools clean and properly chlorinated; remove standing water from pool covers.
- Use landscaping to eliminate standing water that collects on your property.
What the City is doing to control mosquitoes
Ottawa Public Health has a control plan to reduce the risk of the West Nile Virus and Eastern Equine Encephalitis, it includes:
- Surveillance in the mosquito and human population;
- Mosquito traps are placed around the City to determine species and densities of mosquitoes. Subsequent tests are carried out on a weekly basis for WNV and EEE;
- Mosquito larvae surveillance of natural and manmade standing water sites located on City property is ongoing throughout the season;
- A biological larvicide (Bti) is used on surface waters (i.e. ditches, storm water management ponds) throughout the season and applied as needed;
- A chemical larvicide (methoprene) in used to treat non-surface waters. Every City owned roadside storm sewer (catch basin) is treated a minimum of three times per season;
- Source reduction of mosquito breeding sites on City-owned property;
- Mosquito control using adulticide (Malathion) would only be used only in circumstances deemed absolutely necessary. Evidence of intense transmission in birds, and/or mosquitoes as well as human disease would be used to take this decision. While Malathion has never been used in Ottawa, the decision to adulticide rests with the Medical Officer of Health and would depend on updated risk assessments examining the level of risk to the public health from the virus, and the risk to human health from exposure to the adulticide.
Environmental Sensitivities Voluntary Registration
If a vector borne illness does spread to people, the City may be required, by provincial regulation, to adulticide. The City has set up a registry to notify people with environmental sensitivities of adulticiding near their homes. Fill in the registration form [PDF 486 KB] if you would like your name to be added to the list. Please note you may be asked to provide a doctor's certificate at a later date.
Dead bird surveillance and disposal
Effective 2009, Ontario will no longer be conducting a West Nile Virus dead bird surveillance program. Surveillance of the virus is monitored in the mosquito and human population only. If residents have noticed three or more dead crows, ravens, blue jays - or any birds of prey - in one particular area, please notify Ottawa Public Health.
Disposal of dead birds
Dead birds are NOT to be thrown in the garbage (By-law No. 2006-300).
- Bury the bird but not in a plastic bag
- Do not touch the bird with bare hands
- Use a shovel, a pair of heavy duty gloves, or a thick plastic bag to move the bird
- Wash hands thoroughly with soap and water after burying dead bird
Note: If a dead bird is found on City property, please call 3-1-1 for its pickup and disposal
Call the Ottawa Public Health Information Line at 613-580-6744 (TTY: 613-580-9656) or email us at firstname.lastname@example.org for more information. You can also connect with OPH on our Blog, Facebook and Twitter (@ottawahealth) for the latest public health information.