Hantavirus Alerts Increased To Nearly A Quarter Million People After 9th Case Confirmed
September 14, 2012

Hantavirus Alerts Increased To Nearly A Quarter Million People After 9th Case Confirmed

Lawrence LeBlond for redOrbit.com - Your Universe Online

Yosemite National Park officials expanded its public health warning of a hantavirus risk to include more than 230,000 people who visited the California nature reserve since June. The increased alert came after a 9th person was confirmed to have the deadly virus on Thursday.

John Quinley, a spokesman for the National Park Service (NPS), said the ninth victim was from California and stayed in the park in July. Quinley noted that the man had also already recovered from the infection.

While the park and health officials remain on high alert, they insist that their warnings are purely precautionary.

“Because we have heard from concerned guests who stayed throughout the park, today we are reaching out to additional overnight visitors to raise awareness about this rare disease and to ensure they know where to find information regarding hantavirus,” Quinley told Reuters in a statement.

The warnings are for individuals who stayed in Curry Village, Tuolumne Meadows and the High Sierra Camps. “Public health officials have no evidence at this time to indicate that persons who stayed elsewhere in the park this summer were at increased risk of exposure to hantavirus.”

An initial warning was sent out to 1,700 campers last month after the second Yosemite-hantavirus death was confirmed. But alerts gradually expanded following subsequent reports of infections and a third confirmed death. Most of the cases involved campers who stayed at the park´s popular Curry Village, but one case involved a camper who stayed at multiple sites in the High Sierra woodlands of the park.

The US Centers for Disease Control and Prevention (CDC) resounded the park´s warning with their own alert, saying any visitor who stayed in tent cabins at the park between June and August may be at risk for infection.

Hantavirus infection comes from contact with rodent feces, urine, and saliva, or by coming into contact with contaminated food or other items. People can also be infected by a bite from an infected rodent. In Yosemite, the infection is borne of deer mice. They carry the disease with them as they find their way into warm places to nestle and feed, such as the tent cabins at Curry Village in Yosemite.

Most people who contract hantavirus suffer flu-like symptoms at first, followed by severe headaches and muscle pains, and then after two to seven days, some people may begin having trouble breathing. The infection is fatal in about a third of the people who become infected. Patients can go up to six weeks after exposure before developing symptoms of hantavirus. There is no cure or virus-specific treatment for this virus.

The park has reported that an increase in rodent population may be the key driver in the higher number of hantavirus cases this year. Park officials have been laying out traps, catching and analyzing deer mice. Their efforts have about a 50 percent success rate and have identified hantavirus in about 17 percent of mice trapped.

Officials trapped three times as many deer mice last week than were caught in a similar trapping study in 2008, indicating the population has grown, Dr. Vicki Kramer, chief of vector-borne diseases at the state Public Health Department, told BBC News.