June 24, 2025
With mosquito season ramping up, the Wyoming Department of Health (WDH) urges people to protect themselves from mosquito bites this summer to help prevent West Nile virus (WNV) infection.
“We have already had mosquitoes with positive tests for WNV this season,” said Courtney Tillman, epidemiologist with WDH. “As the weather warms up and we spend more time outdoors, we need to remember to take steps to prevent mosquito bites and potential WNV infection.”
WNV is spread by the bite of an infected mosquito. Most people with WNV don’t have any symptoms, but people who develop symptoms report fever, headache, body aches, skin rash, and swollen lymph nodes. Symptoms may begin two to fourteen (14) days after a mosquito bite. A
very small number of individuals develop West Nile neuroinvasive disease with symptoms such as severe headache, fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, or paralysis. People over the age of 50 with chronic diseases are more likely to develop serious
illness.
“We can take simple steps to prevent mosquitoes around our homes and to protect ourselves against mosquito bites,” Tillman said.
To prevent mosquitoes around the home:
● Drain standing water – Mosquitoes lay eggs in shallow, standing water. Prevent
mosquitoes from laying eggs around your home by draining standing water or getting rid
of objects that hold water. This includes keeping gutters cleaned and free of debris.
● Kill mosquito larvae – Use larvicides, such as Bacillus thuringiensis israelensis, for
water that does not drain, such as ornamental ponds and water features. Always follow
product instructions.
● Use window screens – Mosquitoes may try to come indoors. Use tightly-fitted screens in
windows to prevent them from entering.
● Keep lawns trimmed and weed-free – Mosquitoes use tall grass and weeds as resting
spots. Keep grass trimmed and weeds removed to keep mosquitoes away.
To prevent mosquito bites:
● Use insect repellent – When spending time outdoors, use an Environmental Protection
Agency (EPA) approved repellent containing DEET, picardin, Oil of Lemon Eucalyptus,
or IR3535. Always follow label instructions when applying insect repellents. Many
repellents are safe for children and babies and wash off at bathtime.
● Wear long-sleeved shirts and pants – Wear loose-fitting long-sleeved shirts and pants
while outdoors. Treating outdoor clothing with permethrin can add an extra layer of
protection.
● Avoid dawn and dusk – Mosquitoes that spread WNV are most active during dawn and
dusk. Avoid being outdoors during these times.
Information from WDH about West Nile virus can be found at www.badskeeter.org.
