What is West Nile Virus?
The West Nile virus (WNV) is a type of virus known as a flavivirus, which can infect humans and other mammals. In Ontario the main mosquitoes that carry this virus are Culex pipiens and Culex restuans.
How is it spread?
WNV is spread to humans by the bite of an infected mosquito. A mosquito becomes infected when it feeds on the blood of a bird that is carrying West Nile virus. There is no direct person-to-person transmission of WNV. Indirect human transmission can occur through blood and organ donations.
What are the symptoms?
Incubation of illness is usually 2-15 days. WNV can affect people of any age and health. People with weakened immune systems and those over the age of 50 are at greater risk of developing serious illness from WNV.
About 80% of infected individuals will not experience symptoms. Roughly 20% of infected individuals will experience flu-like symptoms, such as headache, fever, nausea, body ache,and skin rash. Less than 1% of individuals infected will experience serious symptoms, such as confusion, disorientation, muscle weakness, vision loss, sensitivity to light, coma or death.
How can I protect myself?
- Use of insect repellent when outdoors. The concentration of DEET should be no greater than 30% for adults and no greater than 10% for children.
- Wear shoes, socks, long pants and long-sleeved shirts when outdoors for an extended period of time or when mosquitoes are active.
- Remove or change all standing water around your home to reduce potential mosquito breeding sites.
References
- Ministry of Health and Long-Term Care. September 2011. http://www.health.gov.on.ca/english/public/program/pubhealth/westnile/wnv_mn.html
- Infectious Diseases Protocol, 2009. Ministry of Health and Long-Term Care.
