Four cases of hantavirus pulmonary syndrome have been identified so far at Yosemite National Park, two of the infected people have died, according to an announcement by the National Park Service Office of Public Health. All the current infections occurred in people who visited that park in June of this year and stayed at Curry Village in "Signature Tent Cabins".
Park officials say they are getting in touch with everyone who stayed in that part of the park from mid-June to the end of August - over 1,700 people. They are being told of the four cases and two fatalities and have been advised to see a doctor immediately if they have any hantavirus infection symptoms.
It can be weeks before symptoms appear. This could mean that more than four people became infected.
Don Neubacher, Yosemite National Park Superintendent, said:
"The health of our visitors is our paramount concern and we are making every effort to notify and inform our visitors of any potential illness. Because people often don't get sick from hantavirus until one to six weeks after exposure, we are encouraging anyone who stayed in Curry Village since June to be aware of the symptoms of hantavirus and seek medical attention at the first sign of illness".
Park officials are still not 100% sure where exactly the latest cases became infected, but they believe it occurred at Curry Village.
A general, non-emergency phone line has been set up which is aimed at dealing with questions and concerns regarding hantavirus in Yosemite National Park. Tel: (209) 372-0822. Officials say calls can be made each day from 9am to 5pm.
What is hantavirus pulmonary syndrome?
Hantavirus pulmonary syndrome is a very infectious disease which starts off with flu-like symptoms but can progress rapidly and become life-threatening. There are several types of hantavirus which can infect humans and cause hantavirus pulmonary syndrome. The virus is carried by rodents, such as the deer mouse. In most cases, infection occurs by inhaling the viruses that rodents expel in their urine and feces.
What are the signs and symptoms of hantavirus pulmonary syndrome? - infection can progress through two stages. Initially the patient may experience:
- Muscle aches and pains
At this stage most people think they have the flu, even doctors may think so, or misdiagnose pneumonia or another viral infection. A few days later the signs and symptoms start to become more severe and may include:
- Cough with mucus
- Panting, shortness of breath
- Lung fluid accumulation
- The heart starts working less efficiently
Anybody who has been in contact with rodents or environments where rodents were seen and experience any of these symptoms should see a doctor straight away. The doctor must be told about the rodents.
What are the causes of hantavirus infection? - rodents are carriers of the hantavirus. Different types of hantavirus exist in certain rodents. The hantavirus that is most common in the USA is carried by the deer mouse.
Typically, the virus comes out of the mouse in its urine or droppings and is later kicked up into the air; this can happen as somebody is sweeping. Humans become infected by breathing it in. They enter the lungs and start to invade the capillaries, causing them to leak. The lungs gradually fill up with fluid, making it harder and harder to breathe.
With the hantavirus that exists in the USA, a human cannot infect another human. The South American variety of hantavirus is human-to-human transmissible.
Risk of infection is greater when you go camping, hunting, hiking, have a home which is infested with rodents, are cleaning out the house, especially areas few people go into (the attic), are cleaning out sheds or buildings that have not been used for a long time, or work in an environment known to have rodents.
Infection is more common in rural parts of the western USA from mid-spring to late summer.
Diagnosis of hantavirus pulmonary syndrome - this is done with blood tests.
How is hantavirus pulmonary syndrome treated? - experts say that the earlier it is diagnosed the easier it is to treat. However, there is no specific treatment.
Patients are hospitalized and breathing support is provided. For those in the second phase, where symptoms are much more severe, patients are placed in the ICU (intensive care unit) where they will receive assisted respiration. In very severe cases, when there is pulmonary distress, the patient's blood is pumped through a machine to be oxygenated, and then returned to the body (extracorporeal membrane oxygenation).
What are the possible complications associated with hantavirus pulmonary syndrome? - as the fluid accumulates in the lungs, breathing gets harder; this can result in a serious drop in blood pressure, and eventual organ failure. When the brain and/or heart fail, the patient dies. In the USA at least 1 in every 3 hospitalized cases is fatal.
The National Park Service Office of Public Health says it is working closely with state and local health departments as well as the CDC (Centers for Disease Control and Prevention). A campaign is underway to raise public awareness.
There have been about 60 cases of hantavirus pulmonary syndrome in California and 587 across the USA since it was first identified in 1993. The following states have confirmed cases since that date: New Mexico, Colorado, Arizona, California, Washington, Texas, Utah, Montana, Idaho, Kansas, South Dakota, North Dakota, and Oregon.
This video footage below was made before the second person died. It shows the interior of the cabins and how they are maintained and kept clean
Written by Christian Nordqvist
Source: CDC, National Park Service