Third batch of West Nile positive mosquitoes trapped in Ajax, Clarington and Oshawa


Published August 25, 2022 at 3:21 pm

The Durham Region Health Department has reported the third discovery of West Nile positive mosquitoes in Ajax, Clarington and Oshawa today.

Positive mosquitoes were first tested in Clarington and Oshawa on July 21, signaling the return of the virus to Durham Region this season. A month later on August 22, the Region announced they trapped yet more positive mosquitoes in Ajax.

Now all three of those municipalities are reporting newly discovered positive mosquitoes. In Clarington and Ajax the mosquitoes were discovered at the same sites they were found on July 21 and August 22.

In Oshawa however the mosquitoes were found in a new location. Durham Region did not specify where in the city they trapped the mosquitoes, only that is was in the north end.

The latest discovery brings the total up to six positive batches so far this year. “The Health Department cautions that with positive test results, it’s important for all Durham residents to take precautions against WNV by avoiding mosquito bites and removing standing water from their properties.”

West Nile virus is mosquito-borne and only spread via bites. A mosquito can bite a bird, pick up the virus and transfer it to people. It does not spread from person to person, nor can it jump from birds to people.

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.

While the risk of infection, and therefore extreme reactions, remains low, the Region offered some advice to avoid it;

  • “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.”



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