Learn About Hantavirus Pulmonary Syndrome | American Lung Association

Learn About Hantavirus Pulmonary Syndrome

Hantavirus pulmonary syndrome (HPS) is a rare but potentially life-threatening viral illness. The virus is transmitted to humans by inhaling infected rodent urine, droppings or saliva. The presence of infected rodents in and around the home environment is the primary risk factor for infection. Even healthy adults can develop this illness.

Key Facts:

  • People exposed to rodent secretions (such as urine or saliva) or with a history of recent travel to rural areas (potential rodent exposure) are at risk for developing HPS.
  • Symptoms include abrupt onset of fever, chills, weakness, nausea, vomiting and abdominal pain followed by difficulty breathing.
  • HPS can be rapidly fatal if not identified and treated promptly.
  • There isn't a vaccine for HPS, and treatment is mainly to support breathing, reducing symptoms and avoiding side effects.

What Is Hantavirus?

The 'Hantavirus' is a group of rodent-borne viruses that causes hantavirus pulmonary syndrome (HPS). It was first identified in the Southwestern United States in 1993 when a group of healthy adults suffered rapid breathing difficulty followed by respiratory failure from an unknown cause. Blood samples from these patients tested positive for exposure to the hantavirus. At the time, prior case reports had linked hantavirus infection to rodents in a single area. An extensive rodent-catching campaign led to the discovery of an unusually large population of infected deer mice near these patients. This was the first large group of patients with HPS attributed to rodent exposure. Several more cases were found when looking back. We now know that hantavirus caused illness in both North and South America, with more than 600 cases identified from 1993 to 2013 (see below).

How Hantavirus Affects Your Body

Hantavirus can infect both rodents and humans, although rodents seem not to get sick. On the other hand, humans can develop severe symptoms and may die.

The hantavirus enters the body by inhaling of virus particles from infected rodent bodily fluids. The virus has a tendency to affect the heart, lungs and kidneys and reduces the function of these organs. The virus also enters the bloodstream where it continues to spread, replicate and cause further organ damage.

The body attempts to fight the virus by creating inflammation. The combination of the virus infecting various organs and the inflammation created by the body leads to intense bodily damage. The virus causes blood vessels throughout the body to become "leaky." In the lungs, leaky blood vessels cause flooding in the air sacs, causing breathing difficulty. When the virus infects the heart, the damage reduces its ability to pump blood around the body. Failure of the heart to pump and leaky vessels with reduction in blood flow causes very low blood pressure ("shock") and oxygen is not available to all the cells of the body. This can rapidly lead to failure of most or all of the organs, and can rapidly lead to death.

Put together, damage to the blood vessels of several organs (specifically heart and lungs) – leading to respiratory failure, "shock," and death lead to what is now known as  "hantavirus pulmonary syndrome" (HPS) or "cardiopulmonary syndrome" (HCPS).

How Serious Is HPS?

HPS is an extremely serious and life-threatening disease. According to the Centers for Disease Control and Prevention (CDC), 606 cases of HPS were identified in the United States between 1993 and 2013. Around a third of these patients died. Cases have been identified in 34 states, with more than 90 percent identified in states west of the Mississippi River.

Several strains of the virus have been identified, with the Sin Nombre Virus (SNV) and Andes virus associated with the most severe form of the illness. Mild infections can cause death in about 10 to 30 percent of cases, whereas in severe illness, case fatality rates are as high as 50 percent.


    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


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