Hantavirus Pulmonary Syndrome (HPS)

Chest X-ray of a patient with hantavirus pulmonary syndrome (HPS); SOURCE: CDC/Brian W.J. Mahy, PhD; Luanne H. Elliott, MS

• Hantaviruses are viruses passed to humans from the urine and droppings of rodents. Hantaviruses can cause a pulmonary infection syndrome.
• Hantavirus pulmonary syndrome (HPS) is a respiratory disease that is a severe form of the infection and can be fatal.
• Early signs and symptoms of HPS for about half of people with HPS include
  • fatigue,
  • fever, 
  • muscle aches, especially in the
    • hips,
    • thighs,
    • back,
    • occasionally, the shoulders.
  • headaches,
  • chills,
  • abdominal issues like nausea, vomiting, diarrhea, and
  • abdominal pain.
• Later signs and symptoms of HPS include coughing and the sensation of tightness around the chest and being smothered.
• The cause of hantavirus pulmonary syndrome (HPS) is inhaling airborne particles of infected rodent urine, droppings, and nesting materials that contain the virus.
• The form of hantavirus in the U.S. is not transmitted from person to person.
• The incubation period for the hantavirus is two to three weeks before symptoms and signs appear.
• The main risk factor for developing hantavirus pulmonary syndrome is exposure to rodents that carry the virus. If you live, work, or travel in an area where carrier rodents are known to live, infection is possible.
• People can easily mistake the signs and symptoms of hantavirus for the flu. Early symptoms include fatigue, fever, muscle aches, headaches, dizziness, chills, nausea, vomiting, diarrhea, and abdominal pain.
• Late stage symptoms of HPS include cough and shortness of breath. Heart and lung failure may occur.
• Blood tests are used to help diagnose hantavirus pulmonary syndrome.
• There is no specific treatment for hantavirus pulmonary syndrome. Supportive care can include oxygen therapy, fluid replacement, and blood pressure medications.
• Hantavirus pulmonary syndrome is fatal in 38% of cases, so early intervention is important.
• Prevention of hantavirus includes limiting contact with potentially infectious rodents in affected areas.

Hantavirus pulmonary syndrome (HPS, also called hantavirus cardiopulmonary syndrome or HCPS) is a respiratory disease that is a severe form of an infection caused by hantaviruses and can be fatal. Hantaviruses are viruses passed to humans from the urine and droppings of rodents.

Signs and symptoms of hantavirus can easily be mistaken for the flu, so it is important to tell your doctor if you live, work, or have recently traveled to places where there are large rodent populations.

The early stage of hantavirus pulmonary syndrome lasts two to eight days, and signs and symptoms may include the following:

• Fatigue
• Fever
• Muscle aches (especially in large muscle groups: thighs, hips, back, and shoulders)
• Headaches
• Dizziness
• Chills
• Gastrointestinal disturbances (nausea, vomiting, diarrhea, and abdominal pain)

After the early stage, the late symptoms of hantavirus pulmonary syndrome are due to fluid in the lungs and include

• cough,
• shortness of breath, and
• heart and lung failure may occur.

These symptoms can lead to organ failure and death in some patients.

What Causes HPS?

The cause of hantavirus pulmonary syndrome (HPS) is inhaling airborne particles of infected rodent urine, droppings, and nesting materials that contain the virus.

The Sin Nombre virus (SNV) and the southern (prototypical) form of the Andes virus cause the most severe forms of hantavirus pulmonary syndrome. The northern form of the Andes virus (Andes-Nort), Laguna Negra virus (LNV), and the Choclo virus cause milder forms of HPS.

What Are the Risk Factors for HPS?

The main risk factor for developing hantavirus pulmonary syndrome is exposure to rodents that carry the virus. Even if you do not see rodents, if you live or work in an area where carrier rodents are known to live, infection is possible. Any activity that can put someone in contact with rodent droppings, urine, saliva, or nesting materials can put a person at risk for hantavirus infection.

• Housecleaning: Sweeping or vacuuming or other actions that stir up dust can release infected particles into the air.
• Work exposure: People in certain occupations, such as pest control, construction, or utility workers, may encounter rodents.
• Camping/hiking: Using shelters or camps that are rodent infested
• Opening/cleaning unused buildings: Structures that have been closed, such as sheds, cabins, barns, garages, and other storage facilities, may house rodents and old droppings.

In the U.S., deer mice (Peromyscus maniculatus), cotton rats, and rice rats in the Southeast, and the white-footed mouse in the Northeast can carry the virus. Rodents shed the hantavirus in their urine, feces, and saliva. When fresh droppings or urine are stirred up, small particles containing the hantavirus become airborne. Transmission of the virus to humans occurs when people inhale air contaminated with the virus.

Other possible ways the virus may spread to people include

• bites from an infected rodent (rare);
• touching something contaminated with infected rodent urine, droppings, or saliva then touching the nose or mouth; and
• eating food contaminated by infected rodent urine, droppings, or saliva.

From the time the virus is first inhaled into the lungs, the incubation period for the hantavirus is usually two to three weeks before symptoms appear (range is one to eight weeks).

Hantavirus is mostly not contagious. The forms of hantavirus in the U.S. cannot be transmitted from person to person, but in rare cases in Chile and Argentina, person-to-person transmission has occurred.

Hantavirus pulmonary syndrome is difficult to diagnose because the are flu-like in nature. A test considered to diagnose HPS, is a positive serological test result is what healthcare professionals use to diagnosis for HPS. 

A doctor or other healthcare professional may order other blood tests to check for abnormalities that could indicate HPS, such as platelet count, and increases in blood levels of lactate dehydrogenase.

The CDC has immunologic tests it may use to detect the viruses.

There is no specific treatment for hantavirus pulmonary syndrome. It is important the infection is diagnosed early so patients can receive supportive care including oxygen therapy, fluid replacement, and blood pressure medications. Kidney dialysis may be needed. Patients are usually admitted to the intensive care unit (ICU) for treatment. An antiviral drug called ribavirin is used to treat different strains of hantavirus including hemorrhagic fever with renal syndrome (HFRS) due to Hantaan virus (HTNV). This drug has not been shown to work against the strain that is common in the U.S. However, in some cases, doctors may try it.

The mortality rate for hantavirus pulmonary syndrome is relatively high. HPS is fatal in 38% of cases, so early recognition of infection is important. The earlier the intervention, the better the prognosis, and those who survive usually recover quickly.

There is no current vaccine that can prevent HPS. The Centers for Disease Control and Prevention (CDC) suggests limiting contact with potentially infectious rodents in affected areas to help prevent hantavirus pulmonary syndrome.

• Minimize or eliminate contact with rodents in the home, workplace, or other areas.
• Cover and seal all holes that might allow rodents to enter buildings.
• Open and air out seldom-used buildings before entering.
• Eliminate potential rodent nesting sites by clearing brush and debris.
• If rodent nesting sites are found, soak nests with 10% bleach prior to removal and wear latex gloves during clean-up.
• If there is a heavy infestation in an area where hantavirus has already been reported, contact the appropriate local, state, or federal health officials before starting clean-up.

The most recent outbreak of the Seoul virus form of hantavirus occurred in 2017. Seventeen people developed infections in 11 states, including Colorado, Georgia, Illinois, Iowa, Minnesota, Missouri, Pennsylvania, South Carolina, Tennessee, Utah, and Wisconsin.

A previous outbreak occurred in 2012 when 10 cases of hantavirus infection were confirmed in people who recently visited Yosemite National Park. There were three deaths. The visitors were from California, Pennsylvania, and West Virginia.