While the monsoon rain Arizona has seen of late is welcome in so many ways, the standing water that follows — often in places you don’t think about around the yard — can become a breeding ground for mosquitoes and the diseases they carry.

The most-common mosquito-borne disease is West Nile virus. Most of those infected will experience no symptoms or mild illness in the form of fever, headache, stiff neck, and body aches. 

In some people, particularly those who are older or immunocompromised or who have comorbidities, West Nile can cause brain inflammation known as encephalitis as well as meningitis, an inflammation of the brain and spinal cord, resulting in confusion, seizures, and even death. 

What can you do? Fight the bite!

Protect your home: You should look for and address standing water that can accumulate in buckets, cans, toys, untended rain gutters, refuse containers, and debris piles. If you open windows, make sure your screens are in good shape so they’ll keep mosquitoes out.

Protect yourself and your family: Use an insect repellent that’s approved by the Environmental Protection Agency. Long-sleeve shirts and long pants will help keep mosquitoes at bay.

Arizona had 1,693 West Nile cases in 2021, with only Graham, Greenlee, and La Paz counties not reporting cases. West Nile was most common in the central deserts, with 1,463 cases in Maricopa County, 115 in Pinal County, and 99 in Pima County.

So far, 2022 has seen a lower number of human cases of West Nile virus than usual, but Maricopa and Pinal counties have reported viral activity in their mosquitoes. In addition Maricopa and Yuma counties have detected St. Louis encephalitis virus in their mosquitoes.

This is a virus related to West Nile, resulting in a very similar illness but less commonly identified in people. 

The season for mosquito-borne illness runs through October, so be sure to visit azhealth.gov/mosquito to learn more about how to protect yourself, your family, and your home.

About the author

Carla Berg is deputy director for public health services at the Arizona Department of Health Services. Visit azdhs.gov.