West Nile virus has reached Utah

West Nile virus has reached Utah. And though it's believed no human has been infected here, health officials are emphasizing the need to protect against mosquito bites.

Friday afternoon, the state Department of Health said the mosquito-borne virus, which is potentially though rarely deadly, has been found in the blood of two chickens near Price, Carbon County, and in mosquito pools in Utah and Uintah counties. It also has been found in a horse in Uintah County and another in Emery County, according to state veterinarian Mike Marshall.

One of the horses, from Lapoint, near Vernal, became ill nine days ago and was so sick it was euthanized last Friday.

There is no vaccine for humans or birds, the other two populations affected by West Nile virus, but a very effective vaccine exists for horses, Marshall said, and it's important to continue vaccinating them. Ideally, the vaccine is given in spring, then a few weeks later, with a final dose given in late July or early August. West Nile virus seems to peak in August and September.

While pointing out the danger of the disease — which killed 284 people last year in the United States and has already killed 11 this year — epidemiologist Gerrie Dowdle emphasized there's no need to panic. "It's not in every mosquito and will not affect every individual who gets bitten," she said. Only 20 percent of those who are infected with the virus show any symptoms, while 1 in 150 infected people would have more severe symptoms.

Mild symptoms in humans include fever, headache, body ache, nausea, vomiting and sometimes rash or swollen lymph glands, according to the federal Centers for Disease Control and Prevention. Severe illness may include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, paralysis and more. While mild symptoms typically last a few days, more serious symptoms can drag on for weeks, the CDC says, and neurological effects may never go away. A small percentage of people who get West Nile virus die. Elderly people are especially vulnerable to the severe, even deadly symptoms.

Birds are most vulnerable to the disease, then horses, followed by humans. Fully one-third of horses exposed to West Nile virus die of an encephalitis-like assault on the central nervous system.

The best defense

The best protection for people, Dowdle said, is not getting a mosquito bite at all.