Hantavirus pulmonary syndrome

Hantavirus pulmonary syndrome is a rare infectious disease that begins with flu-like symptoms. It quickly becomes a more severe disease. The syndrome can lead to life-threatening lung and heart problems. The disease also is called hantavirus cardiopulmonary syndrome.

Several strains of the hantavirus can cause hantavirus pulmonary syndrome. These strains are carried by different types of rodents. In North America, the Sin Nombre virus is spread by the deer mouse. Infection is usually caused by inhaling airborne rodent urine, droppings or saliva that contain hantavirus particles. This strain doesn't pass from person to person.

In South America, the Andes virus is spread by the long-tailed pygmy rice rat. Infections by this strain most often start when a person inhales rodent, urine, droppings or saliva. But it can pass from a person with symptoms to other people. Close contacts, such as family members, are at the highest risk for person to person spread.

Because treatment options are limited, the best protection against hantavirus pulmonary syndrome is to avoid contact with rodents and safely clean up rodent habitats.

The time from infection with the hantavirus to the start of illness may be 1 to 8 weeks. Often symptoms start about 2 to 4 weeks after exposure. Hantavirus pulmonary syndrome advances through two distinct stages.

In the first stage, which can last for several days, the most common signs and symptoms are:

• Fever and chills.
• Muscle aches or pain.
• Headache.

Some people also experience:

• Nausea.
• Stomach pain.
• Vomiting.
• Diarrhea.

As the disease progresses, it can lead to damaged lung tissues, fluid buildup in the lungs, and serious problems with lung and heart function. Symptoms may include:

• Cough.
• Difficulty breathing.
• Low blood pressure.
• Irregular heart rate.

The symptoms of hantavirus pulmonary syndrome can worsen suddenly and may quickly become life-threatening. If you have flu-like symptoms that progressively worsen over a few days, see your healthcare professional. Get immediate medical care if you have trouble breathing.

Rodent carriers

Hantavirus pulmonary syndrome is a human disease found only in North and South America. Each strain of the hantavirus has a rodent carrier.

The deer mouse is the most common carrier of the Sin Nombre virus in North America and Central America. In the United States, most of the infections occur in the states west of the Mississippi River.

Other carriers in North America include the rice rat and cotton rat in the Southeast and the white-footed mouse in the Northeast. Rodent carriers in South America include the rice rat, which spreads Andes virus, and the vesper mouse, which spreads Laguna Negra virus.

Transmission

The virus is present in rodent urine, feces or saliva. You can come in contact with the virus in the following ways:

• Inhaling virus particles when they become airborne from disturbed rodent droppings or nesting materials. This is the most likely form of transmission.
• Eating food contaminated with mouse saliva, urine or droppings.
• Touching things contaminated with the virus, such as a nest, and then touching your mouth, eyes or nose.
• Being bitten or scratched by an infected rodent.

Person-to-person transmission of the virus has only been recorded with a strain of the virus found in South America called the Andes virus.

Effect of the virus

When hantaviruses reach the lungs, they invade tiny blood vessels called capillaries, eventually causing them to leak. Your lungs fill with fluid, called pulmonary edema, resulting in severe trouble with lung and heart function.

Related disease

Another disease caused by different strains of the hantavirus is called hemorrhagic fever with renal syndrome, which causes severe kidney disease. These strains of the virus have other animal carriers in Africa, Asia and Europe.

In the United States, hantavirus pulmonary syndrome is most common in rural areas of the West. However, any exposure to rodent habitats can increase the risk of disease.

Common sites for exposure to rodent nests, urine and droppings include:

• Farm buildings.
• Infrequently used buildings, such as storage sheds.
• Campers or seasonal cabins.
• Campsites or hiking shelters.
• Attics or basements.
• Construction sites.

Activities that can increase the risk of exposure to the hantavirus include:

• Opening and cleaning buildings not used for a long time.
• Cleaning up rodent nests or droppings without appropriate precautions.
• Working in a field that increases exposure to rodents, such as construction, utility work, pest control or farming.

Hantavirus pulmonary syndrome can quickly become life-threatening. Severe disease can result in failure of the heart to deliver oxygen to the body. Each strain of the virus differs in severity. The death rate for the most serious strain can range from 30% to 50%. Milder strains cause death in 10% to 30% of infections.

Keeping rodents out of your home and workplace can help reduce your risk of hantavirus infection. Try these tips:

• Block access. Mice can squeeze through holes as small as 1/4 inch (6 millimeters) wide. Seal holes with wire screening, steel wool, metal flashing or cement.
• Close the food buffet. Wash dishes promptly, clean counters and floors, and store your food — including pet food — in rodent-proof containers. Use tight-fitting lids on garbage cans.
• Reduce nesting material. Clear brush, grass and junk away from a building's foundation.
• Set traps. Spring-loaded traps should be set along baseboards. Exercise caution while using poison-bait traps, as the poison also can harm people and pets.
• Move rodent-friendly yard items. Move woodpiles or compost bins away from the house.
• Air out unused spaces. Open up and air out cabins, campers or rarely used buildings before cleaning.

Safe cleanup procedures

Do not sweep or vacuum rodent droppings or nest areas. Safe cleaning can help prevent the spread of viruses. Follow these steps: 

• Wear a type of mask called a respirator and rubber or plastic gloves.
• Spray the nest, droppings or dead rodent with a household disinfectant, alcohol or bleach and water solution. Let it sit for five minutes.
• Use paper towels to clean up and dispose of towels in garbage.
• Mop or sponge the area with a disinfectant.
• Wash gloved hands and dispose of gloves and mask.
• Wash your hands thoroughly with soap and water.