West Nile cases expected in Salt Lake area

Salt Lake Valley health officials and area mosquito-control experts are warning that human infection with West Nile virus is probably imminent, since the number of infected mosquito pools found in the past week alone exceeds that found in the county in the last three years combined.

The infection level in the county is the highest it's been since the virus was found in Utah in 2004.

The long holiday weekend — complete with barbecues and parades and people sitting outside to watch fireworks — makes human infection likely unless people take precautions to avoid mosquito bites from dusk to dawn, when infected mosquitoes are active, said Sam Dickson, Salt Lake City Mosquito Abatement District manager.

The infected mosquito "numbers are high. It's almost impossible we won't have human cases soon," he said.

The Utah Department of Health reported Friday that people run the highest risk of becoming infected in July, when mosquito populations tend to peak. This year's risk is believed to be much greater than normal.

Experts say the best way to avoid infection is to wear mosquito repellents containing DEET, pacaridin or oil of lemon eucalyptus. They also recommend long sleeves and pants for those outdoors dusk to dawn, and getting rid of standing water around the yard.

Utah County earlier this week reported the season's first human infection in the state. A woman had mild flu-like symptoms, but didn't know she was infected with West Nile until it was detected during screening of blood she had donated. She has recovered.

Infected birds, mosquitoes, a horse and sentinel chickens have been found in several parts of the state, meaning people anywhere in Utah may be at risk and should take preventive steps.

Ten counties so far have detected the presence of West Nile, five in the last week. Davis, Weber, Juab, Millard and Uintah have been added to the list with Duchesne, Emery, Salt Lake, Utah and Washington counties.

Symptoms of the virus can range from hardly noticeable to severe neurological effects and even death. Those most likely to suffer severe effects are the elderly.

Dickson said mosquito-control crews statewide have done an extraordinary amount of work this year to keep mosquito populations down, or it would be even worse. In the Salt Lake area, the amount of runoff in spring and the fact that water was released from a swelling Deer Creek into the marshes northwest of Salt Lake were just two factors that favored high mosquito populations.

---

Contributing: Wendy Leonard

E-mail: lois@desnews.com