US Health Officials Warn International Community Over Hantavirus Outbreak
September 5, 2012

US Health Officials Warn International Community Over Hantavirus Outbreak

Lawrence LeBlond for - Your Universe Online

A week after Yosemite National Park officials reported two cases of deaths caused from contact with feces and urine from Hantavirus-infected rodents, US health officials jumped onboard to alert the international community.

The US Department of Health and Human Services is notifying 39 countries that any of their citizens that may have stayed in Yosemite´s Curry Village tent cabins, or anywhere else within the park this summer, may have been exposed to the deadly deer mouse-borne virus, according to a park official on Tuesday.

Of the 10,000 people who are thought to be at risk of contracting the disease from Yosemite between June and August, about 25 percent have visited from outside the US, Dr. David Wong of DHHS told Reuters. Most of those visitors hailed from Europe, he added.

The lung disease, hantavirus pulmonary syndrome (HPS) has so far killed two men and sickened four others, all US citizens, which prompted the US Centers for Disease Control and Prevention (CDC) to issue an alert. The growing concern is that Yosemite visitors could develop HPS in the next month or so, since incubation periods typically last up to six weeks.

“I want people to know about this so they take it seriously,” Wong said. “We're doing our due diligence to share the information.”

Park officials have since shut down the 91 “signature tent cabins” at Yosemite´s popular Curry Village where they believe most, if not all, of the infections stemmed. Crew at the park are now working to ensure the tent cabins are up-to-date and health officials are continuing to investigate additional cases.

Wong said Hantavirus has killed 64 Californians and nearly 600 Americans since the first two cases were reported in 1993. Early symptoms of HPS include headache, fever, muscle aches, shortness of breath and coughing. The disease can quickly infect the lungs and can cause severe breathing problems and death. The disease has a mortality rate of about 36 percent.

Hantavirus was first identified in the US in 1993, but researchers have since discovered Americans have been dying from the disease since at least 1959. There is no cure for the disease, but early detection through blood tests greatly increases survival rates.

Two unexplained respiratory illnesses in the Four Corners region of Arizona, New Mexico, Colorado and Utah led up to the 1993 discovery.

“If it hadn't been for that initial pair of people that became sick within a week of each other,” the discovery may have gone unnoticed and unchecked, said Dr. James Cheek, of the Indian Health Service.

Within just a few hours of discovering the disease, officials found five further cases of healthy people who died after acute respiratory failure. Lab tests ruled out a new strain of flu and possible bubonic plague, and so the hunt continued. As more and more cases turned up in the Four Corners region, physicians and other science experts worked to narrow down the culprit.

Tissue samples from infected victims had been sent to the Special Pathogens Branch at the CDC for exhaustive analysis, that concluded with experts labeling the samples as hantavirus. Specifically, the virus came from a particular host: the deer mouse.

Once scientists knew what the virus was, they examined stored samples of lung tissue from people who had died of unexplained lung disease in the past. Their analysis revealed that hantavirus had been causing human death since at least 1959--something Navajo native Americans claimed they already knew.

Fast forward nearly 20 years, and similar cases are breaking out in Yosemite, due to infections from the deer mouse-borne hantavirus. Officials said the rodents--which are so small they can slip through tiny cracks and burrow in the insulation of the tent cabins where most of the latest infections derived--leave urine, feces, and saliva behind, and as it dries, it gets swept up with the dust and anyone entering the cabins could inhale the dust particles and contract the infection quite easily.

While American cases of hantavirus cause HPS, those in Europe and Asia cause a different condition, hemorrhagic fever with renal syndrome (HFRS), characterized by fever, headache, stomach symptoms and kidney problems as well as bleeding. About 150,000 cases of HFRS are thought to occur annually worldwide, reports Michelle Roberts of the BBC.

Very few cases of hantavirus infection have been confirmed in the UK.