West Nile positive mosquitoes found in Clarington and Oshawa


Published July 21, 2022 at 4:47 pm

The West Nile virus has returned to Durham Region, as confirmed by tests run on mosquitoes captured in Clarington and Oshawa.

The tests came in on July 21 as the first confirmation of West Nile this season. As a result the Durham Region Health Department has issued a warning to residents to avoid mosquito bites. This can be accomplished, at least in part, by removing an standing water from their property.

West Nile is the leading cause of mosquito-borne disease in North America, spread via bites from infected insects. According to CDC data, most infected with West Nile will feel no symptoms.

However, around one fifth of infected people will experience a fever and other symptoms such as; headache, body aches, joint pains, vomiting, diarrhea, or a rash. Most recovery quickly, but in some cases fatigue and weakness can last for weeks or months.

In about 1 in every 150 infected people (.6 percent) symptoms can become serious and potentially deadly. Infections in these cases develop severe illness including encephalitis, swelling of the brain, or meningitis, swelling of the membranes around the brain and spinal cord.

Severe West Nile often presents as high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Recovery can take many months, and some nervous system effects can be permanent.

People over 60 or who are immunocompromised, are at an elevated risk of severe illness. Approximately one in ten people who develop severe West Nile die.

However, the risk of infection remains low, as of course does severe reaction, according to Durham Region. They have offered some advice to further decrease the risk of infection.

  • “wear shoes, socks, and light-coloured clothing, including long sleeve tops and full-length pants when outside, especially at dusk or dawn when mosquitoes are most active.
  • Use insect repellent containing DEET or Picaridin on exposed skin, following Health Canada’s safety tips on using personal insect repellents.
  • Remove standing water from your property where mosquitoes can breed.
  • Ensure that window and door screens are in good repair to prevent mosquitoes from entering your home.”

Between June and September Durham sets monitor traps throughout the Region. They send the captured mosquitoes out for testing every week to monitor the population. To reduce breeding they treat water basins and stagnant ponds with a larvicide.

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