Fifty people died in Colorado in 2023 from West Nile virus, the worst West Nile virus outbreak in the U.S. in 2023. Photo: Getty Images.

Boulder County Public Health reported its first human case of West Nile virus for this year.

In a press release, the county said it received the first report on Aug. 16 and said the person, who lives in Longmont, is currently in the hospital and was likely bit by a mosquito at home.

The virus was confirmed to be in Boulder County mosquitoes near Longmont in mid-July.

So far, the Colorado Department of Public Health and Environment reports that 13 people have been affected by the virus so far this year. Seven people have been hospitalized, and five were affected with neurologic symptoms.

Boulder is historically one of the counties with the most people affected by West Nile virus since it first became reportable in 2003, according to CDPHE.

Since 2003, there have been 1,064 cases in Larimer County, 913 in Weld County and 886 in Boulder County. Those counties historically have significantly more cases than others in the state, with the next highest being 476 in Adams County, according to CDPHE data.

West Nile virus symptoms typically include fever, extreme fatigue, headache, and body aches, but can occasionally also include skin rashes and swollen lymph nodes. Symptoms generally appear three to 14 days after being bitten by an infected mosquito.

West Nile virus is transmitted to humans through the bite of an infected mosquito. While most infections are mild, more serious infections can cause encephalitis (inflammation of the brain) and/or meningitis (inflammation of the brain’s lining), loss of vision, paralysis, coma, tremors, convulsions and death.

While everyone is at risk of being infected with WNV, people over 50 or with weakened immune systems are at greater risk of developing serious illness. Anyone experiencing these symptoms should consult their health care provider. There is no treatment, cure, or human vaccination for the virus, but health care providers can treat symptoms to help patients feel better and possibly recover more quickly.

Boulder County recommends regularly removing standing water around your home or property. This might include disposing of containers that hold water, draining and clearing out gutters, draining water from pool covers, keeping pools clean, changing the water in bird baths and turning over wading pools and wheelbarrows.