Boulder residents warned about West Nile virus; 4 county residents infected

BOULDER, Colo. - Residents in Boulder County are being warned about West Nile virus after four county residents became ill.

Two of the residents live in Lafayette, one in Boulder and one in Longmont, according to Boulder County Public Health.  All four residents are adults.

Three reported symptoms of fever, headache, chills, body aches, bone or joint pain, muscle weakness, tremors, sever fatigue, and lost appetite but are recovering at home. The fourth person was hospitalized after the symptoms worsened.

Each of the four residents began experiencing symptoms in late July.

West Nile virus is spread to humans from the bite of an infected mosquito.

"This is a reminder to all of us that West Nile virus is still a risk," said Carol Helwig, Boulder County Public Health Communicable Disease Control program coordinator.  "We all still need to take steps to protect ourselves and our families."

Generally, symptoms appear three to 14 days after being bitten by an infected mosquito.

There is no treatment, cure or human vaccination for the virus; health care providers can only treat the symptoms to help patients feel better and possibly recover more quickly.

While most infections are mild, the 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.

"It’s easy to forget that WNV is still a concern since we haven’t seen as many cases in recent years," said Helwig. "But every one of us is at risk for the disease, regardless of where we live in the state, and we should continue to protect ourselves from mosquitoes."

As of Aug. 13, 174 cases of West Nile virus have been reported in 25 states, including 24 cases in Colorado.  Seven people have died from the illness in other states this season. Of all WNV disease cases reported, 47  percent were classified as neuroinvasive disease (e.g., meningitis, encephalitis, acute flaccid paralysis). Generally, the mosquito season extends from late April until mid-October, with the end usually signaled by the first freeze in the fall.

For more information about West Nile virus, mosquito activity in Boulder County, or steps you can take to protect yourself and your loved ones, visit the Boulder County Public Health website at or call the Colorado Health Information Line at 1-877-462-2911.

Boulder County Public Health officials urge residents to take necessary precautions to protect themselves. 

1. Use DEET-enhanced insect repellent or alternative.

2. Wear long sleeves and pants.

3. Avoid the outdoors from dusk until dawn.

4. Drain standing water outside your home. 

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