West Nile Virus Present in 47 States

It’s shaping up to be a bad year for West Nile Virus in the United States, with 47 states reporting positive samples and 38, including Pennsylvania, reporting human cases.

Texas is the hardest hit with about half of the 11 hundred human cases.  Pennsylvania has 8 so far.  Dr. Lyle Petersen, director of the CDC’s Division of Vector Borne Infectious Disease, says the mild winter, early spring and hot summer may be factors. More than half of the human cases have been the more serious neuro-invasive disease, including five of Pennsylvania’s cases.

The human cases in Pennsylvania have occurred in Delaware (2), Bucks, Centre, Franklin, Lancaster, Lebanon and Lehigh Counties.  The state has three blood donor samples testing positive for the presence of the virus.  There have been 7 positive veterinary samples, mostly involving horses and nearly 24 hundred positive mosquito samples.

The CDC is reminding people to take precautions against mosquito bites and take steps around their homes to eliminate standing water that can serve as breeding grounds for mosquitoes.

Dr. Petersen says it takes 3 to 14 days for symptoms to appear, meaning the cases reported now reflect infections from a week or more ago.  He says they expect many more cases to be reported and the risk of infection will continue through the end of September.