Arapahoe County identifies its first human case of West Nile virus

BY TAYLER SHAW TSHAW@COLORADOCOMMUNITYMEDIA.COM

Arapahoe County has identied its rst case of a person being infected with West Nile virus for the 2023 season, the county announced Aug. 3.

West Nile virus is the leading cause of mosquito-borne disease in the continental United States, according to the Centers for Disease Control and Prevention. e virus is commonly spread to people by the bite of an infected mosquito.

Most people infected with West Nile virus do not have symptoms, according to the Colorado Department of Public Health and Environment. However, some infected people can develop a serious and potentially deadly illness.

Given that there are no vaccines to prevent — or medications to treat — West Nile virus in people, health o cials are urging residents to take precautions at all outdoor locations to prevent mosquito bites.

Arapahoe County recommended the following steps to limit exposure to the virus:

Wear an insect repellent that is approved by the Environmental Protection Agency, such as one that includes the ingredient “DEET.” Arapahoe County said these repellents are proven safe and e ective for all people ages 2 months and up, including those who are pregnant and breastfeeding. Stay indoors at dawn and dusk, as this is when mosquitoes are the most active. Avoid recreating around standing water sources such as lakes and ponds. If you are camping, use mosquito netting. Wear clothes to protect against mosquitoes, such as long-sleeved shirts and pants. Drain standing water sources including puddles, gutters, owerpots, tires, pool covers, boats and tarps. Prevent mosquitoes from getting indoors by using an air conditioner or fans rather than open windows. If you do have any windows or doors with openings, put a screen on them. If you live on a property with a septic system, take steps to prevent mosquitoes by ensuring your tank is in good repair and any vents or openings are covered or sealed.

Symptoms of West Nile virus

Symptoms of West Nile virus generally appear about two to 14 days after exposure, the county said. One in ve people develop a fever, body aches, headache, and occasionally, skin rashes and swollen lymph nodes.

e county said mild symptoms of a West Nile virus infection usually pass on their own.

Less than 1% of people infected with West Nile virus will develop severe symptoms that a ect the nervous system, Arapahoe County said.

People who are older than 60 are at a higher risk, as well as people with medical conditions like cancer, diabetes and hypertension.

Severe symptoms of West Nile virus include tremors, high fever, coma, neck sti ness, paralysis, muscle weakness, confusion and disorientation.

e state health department said residents who develop severe headaches or confusion should contact their health care provider.

12 confirmed human cases in Colorado, 1 death e rst human case of West Nile virus in Colorado for 2023 was con rmed in late July in La Plata County, according to the state health department. e Weld County Department of Public Health and Environment con rmed on Aug. 4 the rst death of someone due to West Nile virus in Colorado in 2023. In a news release, Weld County said a 53-yearold resident died from neuroinvasive West Nile virus. e state health department said mosquito populations are at “historic levels” in some parts of Colorado due to the high rainfall this year.

As of Aug. 4, 12 people have been a ected by West Nile virus in Colorado in 2023, according to data from the state health department.

“ is unusually high mosquito activity along with known presence of the virus has caused an elevated risk of West Nile virus transmission to humans,” the department said in a news release.

7 Colorado counties have infected mosquitoes e county said e orts to treat the surrounding area with insecticide were e ective. Environmental health specialists conducted a follow-up test to the same pool where the infected mosquitoes were found, and the samples reportedly came back negative. ose interested in learning more about West Nile virus can visit cdc. gov/westnile.

Arapahoe County is among seven counties in Colorado that have con rmed West Nile virus-positive mosquitoes, the county said.

In July, environmental health experts detected West Nile virus in mosquitoes near the Arapahoe County Fairgrounds, marking the rst known presence of the virus in the county this year.

However, in early August, it was announced that mosquitoes near Heritage High School in Littleton had tested positive for the virus.

“ e season for high mosquito activity typically runs through September, so public health experts caution that our community has a while to go before West Nile (virus) risk peaks and declines,” the county said in its news release.