WNV Spreading Throughout the West

ATLANTA -- Confirming what infection control practitioners and public health officials have suspected, West Nile Virus is gaining momentum in the United States and is expected to spread through August and September.

Dr. Stephen Ostroff, deputy director of the CDC's National Center for Infectious Diseases, reported that currently, a total of 393 human cases of West Nile Virus infection are known within the United States.

"This represents a tripling of the number of cases that we had reported only a week ago, and so of that 393 human cases, 240 of them have been identified and reported to us in the Arbonet system over the past week," Ostroff said.

"About 50 percent of these cases are being reported from Colorado, and the next-highest number is from South Dakota, followed by Texas. As opposed to what was seen last season, where a lot of the earliest activity was in the Mississippi, lower Mississippi River drainage area, a great deal of the West Nile activity that we are currently seeing is in the high plains and in the Rocky Mountain region."

According to the CDC's Morbidity and Mortality Weekly Report (MMWR), there have been 42 states that have reported West Nile activity. Arizona is a new state most recently showing West Nile activity, when a single mosquito pool was proved to be West Nile positive.

"This represents expected continued expansion of West Nile into the far areas of the Western United States, and certainly would be a trend that we would continue to see over the next month or two," Ostroff said.

Ostroff continued, "In terms of recommendations for the public, now is really the time to step up one's prevention activities, whether it's taking measures to reduce sources of mosquitoes around the home or, in particular, taking personal protective measures to reduce your risk of being bitten by mosquitoes when engaged in outdoor activities. This involves personal protective measures, such as use of insect repellents, as well as wearing light, long sleeves and long pants, and also doing what can be done around the home to reduce sources of standing water in order to reduce the likelihood of mosquito breeding."

Source: CDC