Hantavirus pulmonary syndrome (HPS) is a rare but often fatal respiratory disease that people contract from exposure to HPS-infected rodents such as certain types of mice and rats. HPS was first identified in the southwestern United States in the spring of 1993. While HPS is very rare in the United States, it does have a particularly high fatality rate.

People contract HPS when urine, fecal droppings or saliva of infected animals is stirred up and tiny droplets of the HPS virus (hantavirus) become airborne. Materials in a rodent’s nest may contain the virus, which can then be transferred to people who touch the nest before touching their eyes, nose or mouth. A bite from an infected rodent also can transmit a hantavirus.

Symptoms of HPS typically appear one to five weeks after exposure to a hantavirus. Initial symptoms often include fever (which is usually higher in younger people), fatigue and severe muscle aches. HPS quickly progresses to a condition known as adult respiratory distress syndrome (ARDS), in which the lungs fail to adequately transfer oxygen to the blood. This compromises the function of all the body’s organs and often results in death.

In diagnosing HPS, a physician will look for signs of ARDS and will note any decrease in blood pressure (hypotension) or decrease of oxygen levels in the blood (hypoxia). Blood tests also may be performed to look for elevated levels of white blood cells, decreasing platelet counts and other indicators of HPS.

There is no specific treatment for HPS, and a vaccine is not available, although research is ongoing to develop a vaccine. Patients are often admitted to an intensive care unit, where they are given oxygen therapy to help ease them through the period of severe respiratory distress associated with the illness.

To prevent HPS, people are urged to avoid contact with all wild rodents, including squirrels and chipmunks. In addition, it is important to clean up all rodent urine and fecal matter. When cleaning, sweeping or vacuuming should be avoided. These activities may can raise dust and send hantavirus particles into the air – increasing the risk of infection if the virus is inhaled.

All rodent nests should be cleared from the home. Gloves should be worn during the cleaning process, and hands should be thoroughly washed immediately afterwards. Several steps can be taken to keep mice and rats out of the home, including sealing food items and cleaning up after meals, sealing holes on the exterior and interior of the house and removing trash, brush and weeds from outside the home.