Arapahoe County identifies mosquitoes carrying West Nile virus

BY NINA JOSS NJOSS@COLORADOCOMMUNITYMEDIA.COM

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

is spring and summer, which have brought record-high levels of rainfall to much of the metro area, have also created prime breeding grounds for mosquitoes.

e Arapahoe County Public Health Department discovered the mosquitoes carrying the virus through their mosquito surveillance program, which uses traps to capture the insects for testing at a state laboratory. ey use this method to identify pools, or groups of mosquitoes, that are carrying the virus.

e department has three collection sites in the county: at the fairgrounds, near Arapahoe and Parker Road and near Heritage High School.

“It’s not uncommon for positive pools (of mosquitoes) to occur every year,” said Vanessa Fiene, environmental health supervisor at the public health department. “Given that we have identi ed a positive pool in the county, it’s not unlikely that we would see other positive pools in the county as well.”

In 2022, Colorado led the nation in West Nile virus, with a con rmed 206 positive cases and 20 related deaths, according to the Colorado Department of Public Health and Environment. In 2021, Colorado ranked second, falling behind Arizona.

As of July 11, the state health department had zero identi ed human cases of West Nile virus so far this year.

What is West Nile virus?

In humans, the virus can range from being asymptomatic to deadly.

“It really is dependent on the person, you know, it depends on essentially their health,” Fiene said.

Most people are asymptomatic when they are infected with the virus.