Hantavirus Pulmonary Syndrome

Hantavirus pulmonary syndrome (HAN-tuh-vy-rus PUL-mo-nar-ee SIN-drome) is a lung disease that causes respiratory distress (breathing difficulty) and, in some cases, death. Hantavirus, the virus that causes the disease, is carried by rodents.

What is Hantavirus Pulmonary Syndrome?

Hantavirus pulmonary syndrome, or HPS, is a potentially deadly disease that attacks the lungs. A family of viruses called hantavirus causes HPS. These viruses live in rodents but do not make them sick. The Sin Nombre virus (SNV) hantavirus causes most HPS in the United States, but some cases have come from the Bayou, the New York, and the Black Creek Canal viruses.

Rodents, usually mice and rats, shed hantavirus in their saliva, urine, and droppings. Humans catch the virus when they disturb dried droppings (by sweeping, for example) and inhale the particles that are sent into the air. People can also contract hantavirus by touching an infected animal or its droppings and then touching their nose or mouth. Eating food or drinking water contaminated by rodent droppings is another source of infection. Rodent bites, although rare, can also spread the disease.

The most common carriers of hantavirus are deer mice (found almost everywhere in North America), cotton rats and rice rats (found in the southeastern United States and Central and South America), and white-footed mice (found in most parts of the United States and Mexico). Cats and dogs do not carry hantavirus and they cannot catch it from rodents. However, cats and dogs can spread hantavirus to humans if they bring an infected rodent into a home or other buildings where people live or work.

Is HPS Common?

HPS is rare. Health authorities first recognized the disease in the United States in 1993, and the U.S. Centers for Disease Control and Prevention (CDC) recorded only 333 reported cases through early 2003. Although HPS occurs in people throughout North and South America, most cases in the United States appear in the Southwest and in places that are infested with rodents.

People of every age, sex, and race can contract HPS, but it is not contagious and cannot be spread by sneezing, coughing, kissing, or having other bodily contact.

Mice and rats shed hantavirus in their saliva, urine, and droppings. The rice rat (seen here) primarily inhabits the southeastern United States and carries the Bayou virus, a form of the disease that has been found in Louisiana.

What Are the Symptoms of HPS?

The first symptoms of HPS usually appear 1 to 5 weeks after a person has been exposed to the virus. HPS can be difficult to diagnose because the early signs, such as fever, tiredness, and body aches, are similar to those of the flu. About half of the people who catch HPS also may experience dizziness, chills, nausea, vomiting, abdominal ^* pain, or headaches.

From 2 to 5 days after the first symptoms, a person infected with hantavirus starts coughing and experiences shortness of breath. The disease quickly becomes more severe, and people who do not receive immediate treatment may become extremely ill and go into shock ^* , needing intensive care in a hospital.

How Do Doctors Diagnose HPS?

A doctor may suspect HPS if a person with flulike symptoms complains about difficulty breathing, especially if the person has been exposed to rodents or rodent droppings. To confirm the diagnosis, the doctor uses blood tests to see if the person has developed antibodies ^* to a strain ^* of hantavirus. Chest X rays or ultrasound ^* images can help the doctor check the condition of a person's heart and lungs.

How Is HPS Treated?

HPS is a serious disease, and someone who has it needs treatment in a hospital's intensive care unit. There he might be given fluids, have his blood pressure monitored, and have a tube inserted in his throat to help him breathe. Because a virus causes HPS, antibiotics do not work against it, although an antiviral drug may help some patients. According to the CDC, 38 percent of reported cases of HPS have been fatal.

Doctors today know more about the disease and are quicker to get patients into treatment. The earlier people with HPS receive help, the better their chances of survival. Recovery from HPS is fairly fast, although patients may feel worn out for several months.

Can HPS Be Prevented?

There is no vaccination available for HPS. The best way to avoid contracting the virus is to get rid of possible sources of infection, which means avoiding woodpiles and other places where rodents live outdoors and keeping homes and workplaces free of mice and rats. Experts also recommend sealing holes where rodents can enter (they can squeeze through spaces as small as .25 inch in diameter) and wearing a mask and gloves when cleaning out areas with rodent droppings.