With winter weather approaching, Utah health officials have stopped active surveillance of West Nile virus. The 2007 season proved to be less severe in both human and animal activity than the 2006 season, but West Nile virus still caused serious illness and one reported death. This year, 68 human cases were reported to the Utah Department of Health as opposed to 158 during 2006.

Human cases were reported throughout the state, but an increase was noted in the northern part of the Wasatch Front and the Bear River area. Twenty-six (39 percent) of the reported human cases were classified as neuroinvasive, the most serious form of the disease. Twenty-eight cases resulted in hospitalization and one person died. Although the majority of cases occurred in individuals over the age of 40, cases were reported in all age groups. Risk of disease exists for all age groups.

Animal activity followed the same pattern as the human activity, with an increase in the northern part of the Wasatch Front and the Bear River area. Statewide, 18 horses, 19 birds, 74 sentinel chickens and 225 mosquito pools tested positive for West Nile virus in 2007. This compares with 59 horses, 76 birds, 107 sentinel chickens and 446 mosquito pools during 2006.

Since West Nile virus was first detected in Utah in 2003, it has been found in every major area of the state and was detected in 18 counties this year. The West Nile virus active surveillance season usually starts mid-May and continues through October, however, horses and humans are tested year round. West Nile was first detected this season during the week of June 16th in a mosquito pool in Salt Lake County.

“Public health officials throughout the state have dedicated significant time and energy working to prevent the spread of West Nile virus,” said UDOH epidemiologist JoDee Summers. “This year's numbers suggest that those efforts, combined with the cooperation of the general public, are paying off.”

The Utah Department of Health would like to thank all of its partners for their help in the 2007 West Nile Virus season and for making public health an important issue.

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