What is West Nile virus?
West Nile virus (WNv) is an arbovirus (a virus that is transmitted by arthropods – a group which includes insects). WNv is transmitted to people by infected mosquitoes. About one in five people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with febrile illness recover completely, but fatigue and weakness can last for weeks or months. However, the elderly and those with certain chronic medical problems, including problems with their immune systems, can experience more intense illness.
Early symptoms of WNv can include fever, muscle weakness, stiff neck, confusion, severe headache, sudden sensitivity to light, tremors, numbness, or vision loss. About one in 150 people who are infected develop a severe illness affecting the central nervous system, such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord). If individuals believe they are experiencing early symptoms of WNv, they are encouraged to contact their health care provider.
Mosquitoes acquire WNv by feeding on infected birds. You cannot get the disease from person-to-person contact. No specific treatment or vaccination is available for WNv. For severe illness, supportive therapy is provided.
Incubation period
Typically two to six days, but can be up to 14 days.
Protect yourself from WNv:
- Wear light-coloured clothing and minimize exposed skin if you are out at dawn and dusk.
- Use an insect repellant containing DEET or Icaridin and follow manufacturer’s directions.
- Consider wearing permethrin-treated clothing.
- Remove any sources of standing water where mosquitoes can lay their eggs, including jars, discarded tires, clogged gutters, yard decorations, and stock tanks.
- Empty bird baths every other day and cover rain barrels with a tight-fitting fly screening.
- If you encounter a dead bird do not handle it with bare hands.
Related Links:
- West Nile Virus – Government of Ontario
- West Nile Virus – Health Canada
- West Nile Virus: Symptoms & Treatment – CDC
- Permethrin-treated Clothing – PHAC
