Hanta virus

Alternative names:

hantavirus pulmonary syndrome

Definition:

A disease characterized by flu-like symptoms followed by respiratory failure.

Causes, incidence, and risk factors:

Hanta virus, a distant cousin of the ebola virus, has been recognized as a cause of disease in countries such as China for many years. Some Hanta viruses cause kidney disease. In the United States, disease caused by Hanta virus has probably always existed but in such low numbers that it was not recognized. A 1993 outbreak of fatal respiratory illness on an Indian Reservation in the Four Corners area (the border of Utah, Colorado, New Mexico, and Arizona) led epidemiologists to the discovery of Hanta virus as the causative agent. Since that discovery, Hanta virus disease has been reported in every western state except Washington, and in many eastern states.

Hanta virus is carried by rodents, particularly deer mice, and is present in their urine and feces. The Hanta virus does not cause disease in the carrier animal but it does in man. Humans are thought to become infected when they are exposed to contaminated dust from the nests or droppings of mice. The disease is not, however, passed between humans. Contaminated dust is often encountered when cleaning long-vacated dwellings, sheds, or other enclosed areas.

The federal Centers for Disease Control and Prevention (CDC) reported that hantaviurs-carrying rodents have been found in at least 20 national parks and that it's possible that the virus is in all of the parks. Epidemiologists at the CDC suspect that campers and hikers may have a higher chance of contracting the disease than most people. This is due to the fact that they pitch tents on the forest floor and lay their sleeping bags down in musty cabins. So far, however, out of the 110 plus cases that have been reported in the United States, only 2 of them were directly linked to camping or hiking.

The initial symptoms of Hanta virus disease closely resemble influenza. The disease begins abruptly with fever, chills, muscle aches (myalgia), headache, nausea and vomiting, and malaise. A dry cough may be present. The fever may be higher in younger people than in older people. For a very short period, the infected person feels somewhat better but this is followed within a day or two by an increased respiratory rate caused by a seepage of fluid into the lungs. The initial shortness of breath is subtle and the patient may be unaware of it, but progression is rapid. The patient bleeds internally, and ultimately develops respiratory failure.

An effective treatment for Hanta virus is not yet available. Even with intensive therapy, over 50% of the diagnosed cases have been fatal.