The first case of West Nile virus in La Plata County in 2025 was reported to La Plata County Public Health Department in July.
LPCPHD Director Theresa Anselmo said the patient’s case was reported to the health department in early July and the patient had recovered at home.
When a case of a disease such as West Nile virus is reported to LPCPHD, the health department launches an investigation into where and how the patient might have been exposed to and contracted the illness, she said. The investigation can take time to conclude.
Anselmo said cases of West Nile virus in La Plata County are fairly rare, with an exception in 2023 when 11 cases were reported. There was one reported case last year and the patient was hospitalized, although they recovered.
The Colorado Department of Public Health and Environment reported the first death this year of a West Nile patient in Colorado, a resident of Lafayette, Boulder County, one week ago on July 25.
Eleven Coloradans have been affected by the virus this year as of Friday. Cases have been reported in La Plata, Adams, Boulder, Pueblo, Broomfield, Douglas, Larimer and Weld counties, state public data showed. Three patients were hospitalized and five patients have exhibited neurological symptoms.
Importantly, Anselmo said, eight out of 10 people who contract West Nile virus never develop any symptoms.
“Severe illnesses are more likely to occur in older people who are at greater risk for that severe illness, similar to the reasons that they are more susceptible to severe illnesses of all sorts of types,” she said.
She added immunocompromised individuals, people with serious illnesses such as cancer, diabetes, hypertension and people who have recently received organ transplants are also at higher risk of developing a more severe form of the disease.
West Nile virus symptoms often include fever, headache, body aches, joint paints, vomiting, diarrhea or rash, according to LPCPHD. Although rare, severe symptoms include high fever, headache, neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.
A vaccine for West Nile virus has not been developed and the only treatment is supportive care. When symptoms occur, they typically do so two to 14 days after infection, the health department cautioned in a news release.
It’s time to call a doctor if one experiences a fever, severe headaches or confusion after receiving a mosquito bite, Anselmo said.
Mosquitoes are the common culprit behind transmission of West Nile virus in Colorado, and public health agencies offer simple precautionary measures to reduce the likelihood of coming into contact with an infected insect.
Anselmo recommended using EPA-registered insect repellents – and following their instructions to allow the repellents enough time to activate; wearing long-sleeve shirts and pants, particularly at dawn and dusk when mosquitoes are most active; installing and repairing screens on windows and doors; and using air conditioning to deter mosquitoes.
Eliminating standing water where mosquito larvae thrive is also advised. Water dishes for pets, plant pots, pool covers, discarded tires and other items or areas where water can pool should be drained, she said.
CDPHE recommends treating standing water that cannot be drained with a Bti larvicide.
While mosquitoes can transmit West Nile virus to a human via a bite, humans are “dead-end hosts,” Anselmo said. That means one infected person cannot spread the disease to another person, or even to another mosquito through a post-infection bite.
West Nile virus made its debut in the United States and North America in New York City in 1999. An unprecedented number of cases in North America in 2002 marked the largest recorded West Nile outbreak anywhere, according to the National Institutes of Health.
The 2002 outbreak caused 4,156 human cases and 284 deaths in the United States. However, that record was short-lived, as cases more than doubled the next year with 9,862 cases and 264 deaths, U.S. Centers for Disease Control and Prevention data showed.
For comparison, there were 1,791 cases and 164 deaths nationwide last year.
“It is very preventable” as long as people take proper precautions, Anselmo said.
cburney@durangoherald.com
