Take measures to protect yourself from West Nile virus this summer

August 16, 2022
Dr. Leslie Tengelsen, Idaho State Public Health Veterinarian

West Nile virus (WNV) positive mosquitoes were detected in Ada, Payette, and Elmore counties this month, and public health officials are urging Idahoans to protect themselves from biting mosquitoes when they’re outdoors.

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Every year the risk for acquiring WNV goes up later in the summer as Culex mosquito populations increase. Culex tarsalis and Culex pipiens are the most likely mosquito species to carry and transmit WNV in Idaho, and we fully expect to find additional WNV-positive mosquitoes in additional counties this summer. That means the risk of acquiring the infection from mosquitoes will remain elevated until a killing frost eliminates the risk sometime this fall.

Last year, 14 Idaho counties reported WNV-positive people, mosquitoes, horses, and/or birds. WNV infections were reported in 16 people, 15 horses, and two birds. WNV contributed to 2 human deaths last year.

WNV is not spread from person-to-person through casual contact and is usually contracted from the bite of an infected mosquito. Symptoms of infection can include fever, headache, body aches, nausea, and sometimes swollen lymph glands or a skin rash. Infection can result in severe illness, especially in people 50 years and older. If you feel ill, talk to your healthcare provider about testing for WNV.

It is important for people to protect themselves from mosquitoes, particularly between dusk and dawn when mosquitoes are most active. In addition, everyone should:

  • Cover up exposed skin when outdoors and apply DEET or other EPA-approved insect repellent to exposed skin and clothing. Carefully follow instructions on the product label, especially for children.
  • Insect-proof your home by repairing or replacing screens. 
  • Reduce standing water around homes and properties. Check and drain toys, trays, and pots that are outdoors and can hold water.
  • Change bird baths, static decorative ponds, and animal water tanks weekly to reduce suitable mosquito habitat.

WNV does not usually affect domestic animals but can cause severe illness in horses and some species of birds. Although there is no vaccine for people, there are several vaccines for horses, which should be vaccinated annually.

For more information, please visit http://westnile.idaho.gov.