Basics about hantavirus outbreak in Yosemite

Basics about hantavirus outbreak in Yosemite »Play Video
In this photo from Sunday Oct. 23, 2011, tents are seen in Curry Village in Yosemite National Park, Calif. Two people died after contracting a rare rodent-borne disease that might have been linked to their stay at this popular lodging area in Yosemite National Park. (AP Photo/Ben Margot)

Holiday weekend campers, planning to head to Yosemite National Park, have flooded rangers with questions about safety after six recent cases of hantavirus. The illness is fairly rare, but Kern County has also seen four cases of Hantavirus in past years.

As of Friday, in the cases linked to Yosemite, the California Department of Public Health reports two victims have died, three are recovering, and one was still listed as hospitalized and improving.

"CDPH is working closely with the National park Service and the Centers for Disease Control and prevention to further investigate the cluster of Hantavirus Pulmonary Syndrome cases in Yosemite and reduce the risk of other visitors becoming ill from the virus," their statement read.

Four people who got sick, including both who died, stayed in cabins in Curry Village in the park. One stayed in an unspecified area of Curry Village, and the other case is still being investigated, according to the CDPH.

Hantavirus is usually contracted by contact with mouse droppings or urine.

In Kern County, that's exactly what happened. The county public health department shows two cases in 1998, and two more in 1999.

"All involved men," Bill O'Rullian told Eyewitness News. "They were not random situations where they didn't know how they had been infected." He investigated the cases as part of his job with the Kern County Environmental Health Department.

"At least once we realized what they had been doing before the infection, all of them were involved in cleaning heavy infestations from mice." O'Rullian said. Adding, in two cases the victims were using a vacuum in a confined space.

He recalls that three victims died. One man worked in Sand Canyon near Tehachapi, where he was exposed to mouse droppings, according to O'Rullian.

One victim was living in Inyokern. Another was a young man in Shafter, who was exposed to mouse droppings as he cleaned out a garage, according to O'Rullian. He says a fourth victim who worked in an oilfield near Taft, got sick, but survived.

O'Rullian says it's important to take precautions when cleaning up any place where mice have been.

"You shouldn't use a vacuum cleaner -- or a broom -- where you're going to be raising a lot of dust," O'Rullian advises. "Use a wetting solution, a little spray bottle, you can spray with Lysol or you can spray with water." He also says it's important to wear a mask, gloves, and even eye protection.

O'Rullian said the victims in Kern County were all cleaning out sheds, garages or other small areas when they were infected with the virus.

"Breathing small particles of mouse urine or dropping that have been stirred up into the air is the most common means of acquiring infection," reads the statement from state health officials.

On Friday afternoon a state health department spokeswoman emailed Eyewitness News their latest advisory.

"All Californians should continue with their plans this holiday weekend even if they include camping, but should avoid contact with wild rodents," the statement reads. "Contact with rodent droppings, or urine is especially problematic. Campers should also avoid entering structures where wild rodents might be present."

That's a concern in places like camping areas; or areas like a garage, shed or cabin.

"No matter if it's here on the valley floor, or up in an area where recreation takes place in the mountains, you need to take some basic precautions," O'Rullian said.

He added a very good precaution is working to prevent mice and rats in the first place. O'Rullian suggests making sure there aren't gaps under doors or other openings where rodents can get in. He said "snap traps" are also a good idea.


The Associated Press offers answers to common questions about mice and the hantavirus linked to death of two people who visited Yosemite National Park:

How common is hantavirus pulmonary syndrome?

Up to 20 percent of all deer mice carry the virus, though levels can be higher. The illness is rare. Through 2011, there have been 587 documented cases since the illness was first identified in 1993.

How is it spread?

The most prolific carrier is the deer mouse, which prefers woodlands and high elevations, and can be found in desert areas. The virus in the saliva, feces and urine of infected mice is spread to humans who inhale airborne dust and aerosol particles. Symptoms develop in one to six weeks.

How do you tell a deer mouse from other mice?

House mice have solid colors, but deer mice range from gray to reddish brown, with white on their underbellies and sides of their tails.

Who is most susceptible?

Unlike the West Nile Virus, which is particularly hard on the elderly and people with compromised immune systems, there is no standard risk factor for humans when it comes to the hantavirus. Among the known cases, 63 percent have been men and 37 percent women. The range of ages was 6 to 83.

Can I catch it from someone who is sick?

Probably not. There have been no documented cases of hantavirus being spread by human to human contact.

What is the mortality rate?

More than 36 percent of people stricken with hantavirus have died from it. In 2011, half of the 24 people who got it died.

What are the signs?

It begins with chills, fever and muscle aches then progresses into a dry cough, headache, nausea and vomiting, then shortness of breath. People with hantavirus are put in intensive care, placed on oxygen and given medicine to prevent kidney failure.

How can I avoid exposure?

Open buildings that have been closed for a period of time and let them air out for 30 minutes. Spray mouse droppings with a water and bleach mixture, wait 15 minutes and mop up or wipe with paper towels.

Will I get it if I go to Yosemite National Park?

The chances are slim. More than 4 million people visit the park each year. Since 2000 there have been six suspected and confirmed cases.

Sources: Centers for Disease Control and Prevention, California Department of Public Health, the U.S. National Library of Medicine, National Park Service.