As people head out to deer camps or cabins this fall, they may want to take some precautions to safeguard themselves against a potentially fatal virus that sickened nine and killed three in California's Yosemite National Park this past summer, warned an expert in Penn State's College of Agricultural Sciences.

Hantavirus has killed several Pennsylvania residents over the years, said David Wolfgang, extension veterinarian and field studies director in Veterinary and Biomedical Sciences. And he emphasized that caution -- but not panic -- is warranted.

Hantavirus first was diagnosed in the United States in the Four Corners area shared by New Mexico, Arizona, Colorado and Utah in 1993, when several young adults complained of acute respiratory distress and about half soon died.

Before this year, according to the U.S. Centers for Disease Control and Prevention, a total of 587 cases of hantavirus pulmonary ayndrome (HPS) were reported in the United States. Of these, 556 cases occurred following the initial identification of HPS in 1993, and 31 cases were identified retrospectively. About 36 percent of all reported cases have resulted in death.

HPS is a serious, acute lung disease that causes the lungs to fill with fluid, Wolfgang explained. While there have been only a few cases reported in Pennsylvania more than a decade ago, it is wise to be careful when cleaning out hunting camps and cabins.

"Several species of wild rodents, such as the deer mouse and the white-footed mouse, have been linked to the virus," he said. "You could be at risk when opening or cleaning a hunting camp or cabin -- that may put you in contact with rodent droppings, urine or nesting materials.

"Because the virus enters the lungs through contaminated dust, you should avoid touching rodent droppings and actions that would raise dust."

The Centers for Disease Control website lists recommendations for hantavirus prevention and control at http://www.cdc.gov/ncidod/diseases/hanta/hps/noframes/prevent.htm.

"They are simple precautions that most of us already follow in cleaning our homes," Wolfgang said.