Yosemite National Park, California, USA Credit CDC
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Overnight we’ve news that two more cases of Hantavirus infection have been detected among recent visitors to Yosemite National Park in California, bringing the total now to six, with two fatalities.
The following press release, from the California Department of Public Health, mentions four new cases, but two of those were previously announced (see Hantaviruses Revisited for earlier reports and background on the virus).
Hantavirus Found in Four More Visitors to Yosemite National Park
Date: 8/30/2012
Number: 12-049
Contact: Anita Gore or Heather Bourbeau - (916) 440-7259
SACRAMENTO
The California Department of Public Health (CDPH) today reported four additional cases of Hantavirus Pulmonary Syndrome (HPS), bringing the total number of people infected with the hantavirus who visited Yosemite National Park to six.
“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 this virus,” said CDPH Director, Dr. Ron Chapman. “CDPH is continuing to monitor cases of Hantavirus Pulmonary Syndrome in persons who visited Yosemite National Park.”
To date, HPS has been confirmed in six persons who visited the park between early June and mid July 2012. Five are California residents and one is a resident of Pennsylvania. The PA patient and one CA patient have died, three have recovered and one is currently hospitalized but improving. Four, including both fatalities, lodged in the “signature cabins” of the Boystown area of Curry Village, one lodged in an unspecified area of Curry Village, and one is still under investigation.
The six individuals infected are residents from the Sacramento region, San Francisco Bay area, Southern California and one from Pennsylvania.
On August 28, per recommendations from CDPH, Yosemite National Park closed all tent cabins in the Boystown area indefinitely. The National Park Service has issued communications to guests who had stayed in the Boystown area between June 10 and August 24, alerting them to the HPS concerns and recommending that they seek medical attention if ill.
As the epidemiological investigation and search for additional cases continues, a number of local media outlets are reporting that warnings from the state urging that park officials educate campers about the risks from the Hantavirus were not acted upon.
State had warned Yosemite about hantavirus
Christina Jewett, California Watch
Updated 11:07 p.m., Thursday, August 30, 2012
State public health scientists have recommended twice in the past five years that Yosemite National Park authorities educate visitors about hantavirus, a rare disease linked to the deaths of two park visitors this summer - but park officials did not warn tourists until after the disease showed up in recent weeks.
An AP report by Joseph Dearen (see 2 more Yosemite visitors have mouse-borne virus) outlines steps taken by the park service last spring to reduce the threat from Hantavirus after 18% of mice trapped and tested around the park tested positive for the virus.
According to a number of sources, roughly 20% of deer mice routinely carry the virus, making the survey numbers at Yosemite about average.
The State of California maintains a FAQ on Hantaviruses, from which the following is excerpted:
How are hantaviruses maintained in nature?
Hantaviruses are maintained in nature in wild rodents. In California, only deer mice carry and shed SNV. Other rodents such as squirrels, chipmunks, and house mice are rarely, if ever, infected and do not pose a risk of HCPS to humans.
How do you get HCPS?
Infected rodents shed hantavirus in their urine, droppings, and saliva. Most HCPS patients become infected by breathing air contaminated with rodent urine or droppings, such as when cleaning out a rodent-infested space. This most commonly occurs in small, confined spaces where there is little air circulation. Rarely, individuals can also be infected by:
1) consuming food contaminated with rodent urine or droppings;
2) touching surfaces where rodents have been, and then putting their hand in their mouth;
3) being bitten by an infected rodent.
Meanwhile the CDC has updated their Hantavirus web pages in response to this outbreak:
Signs & Symptoms for Hantavirus Pulmonary Syndrome (HPS)
Due to the small number of HPS cases, the "incubation time" is not positively known. However, on the basis of limited information, it appears that symptoms may develop between 1 and 5 weeks after exposure to fresh urine, droppings, or saliva of infected rodents.
Early Symptoms
Early symptoms include fatigue, fever and muscle aches, especially in the large muscle groups—thighs, hips, back, and sometimes shoulders. These symptoms are universal.
There may also be headaches, dizziness, chills, and abdominal problems, such as nausea, vomiting, diarrhea, and abdominal pain. About half of all HPS patients experience these symptoms.
Late Symptoms
Four to 10 days after the initial phase of illness, the late symptoms of HPS appear. These include coughing and shortness of breath, with the sensation of, as one survivor put it, a "...tight band around my chest and a pillow over my face" as the lungs fill with fluid.
Is the Disease Fatal?
Yes. HPS can be fatal. It has a mortality rate of 38%.
And answers to two very common questions about this disease can be found on the CDC’s Hantavirus Transmission page (emphasis mine).
The types of hantavirus that cause HPS in the United States cannot be transmitted from one person to another. For example, you cannot get the virus from touching or kissing a person who has HPS or from a health care worker who has treated someone with the disease. You also cannot get the virus from a blood transfusion in which the blood came from a person who became ill with HPS and survived.
Can pets transmit HPS to humans?
The hantaviruses that cause HPS in the United States are not known to be transmitted by any types of animals other than certain species of rodents. Dogs and cats are not known to carry hantavirus; however, they may bring infected rodents into contact with people if they catch such animals and carry them home. Guinea pigs, hamsters, gerbils, and rodents from pet stores are not known to carry hantavirus.
You’ll find details on investigation into the Yosemite outbreak at:
August 2012 - Yosemite National Park Outbreak Notice
Updated: August 29, 2012
On August 27, 2012, The National Park Service (NPS) announced that there were 3 confirmed cases and 1 probable case of Hantavirus Pulmonary Syndrome (HPS) in visitors who stayed at Curry Village in Yosemite National Park since June of this year. Public health officials believe that these visitors may have been exposed to Hantavirus while staying at the Signature Tent Cabins in Curry Village. Two people have died. CDC and the California Department of Public Health (CDPH) are working with the National Park Service in responding to the situation.
The park is contacting visitors who stayed in the Signature Tent Cabins from mid-June through the end of August, advising them to seek immediate medical attention if they exhibit symptoms of HPS. Hantavirus is a rare but serious disease and confirmed cases should be reported to CDC via state health departments
And a final note, while hantavirus outbreaks garner a lot of headlines, human infection with this virus is exceedingly rare in the United States.
Fewer than 600 cases have been registered since the early 1990s.
With roughly 4 million visitors to Yosemite National Park each year, and only six cases so far, the absolute risk of contracting this virus while camping there is extremely low.
