Hantavirus Pulmonary Syndrome (HPS)

Hantavirus Pulmonary Syndrome (HPS) is a zoonotic disease transmitted through the inhalation of aerosols or contact with saliva, faeces or urine of infected rodents. It is a severe, sometimes fatal disease in humans caused by infection with a hantavirus (in the Bunyavirales order). The case fatality ratio for HPS is estimated at 35—50 per cent.

Numerous individual cases and small clusters of hantavirus cases have been reported in Argentina, Bolivia, Brazil, Chile, Ecuador, Paraguay, Panama, USA, Uruguay and Venezuela. Large outbreaks have been rare and have usually been associated with human disturbance and land-use changes or with unusual environmental events such as increased rainfall or periodic bamboo flowering (i.e. environmental conditions that influence a growth in the reservoir rodent’s population).

Other diseases related to hantaviruses include Haemorrhagic Fever with Renal Syndrome (HFRS) which is found in Europe, Asia and parts of Africa and is generally less severe.

The following are standard case definitions to allow national health authorities to interpret data in an international context. However, during an outbreak case definitions may be adapted to the local context and the Red Cross Red Crescent should use those agreed/established by national health authorities. NB: Consider that during community surveillance, volunteers should use broad (simplified) case definitions to recognize most or all possible cases and encourage them to seek care. Other actors such as healthcare workers or investigators studying the cause of a disease, on the other hand, can use more specific case definitions that may require laboratory confirmation.

Clinical case definition: An illness characterized by one or more of the following clinical features: respiratory illness with respiratory compromise requiring supplemental oxygen and fever developing within 72 hours occurring in a previously healthy person. The clinical and radiographic examination resembles the acute respiratory illness distress syndrome (ARDS) with excess of fluids in the lungs (pulmonary oedema); OR an unexplained respiratory illness resulting in death, with an autopsy examination demonstrating noncardiogenic pulmonary oedema without an identifiable cause.

Confirmed case definition: A clinically compatible case that is laboratory confirmed.

Case definition source of information: https://www.who.int

Single case.

• Anyone who comes in contact with rodents that carry hantavirus is at risk of HPS.
• People living in rural areas where rodents hosting the virus might be found.
• For Andes virus only: close contact with individuals with HPS, like caregivers and health workers or crowded settlements where an outbreak occurs.

Attack rates will vary from one outbreak to another. In case of an outbreak, consult the latest information provided by health authorities.

• People with weakened immune systems.
• Immunosuppressed persons such as those receiving chemotherapy, transplant recipients or HIV carriers.
• People with chronic diseases such as renal disease, cancer, chronic lung or liver disease and diabetes.

New World hantaviruses (i.e. Sin nombre, New York, Back Creek and Bayou hantaviruses in Northern America, Andes viruses and other hantaviruses in Central and South America) cause HPS.

Hantaviruses from the Bunyaviridae family cause a group of clinically similar diseases called Haemorrhagic Fever with Renal Syndrome (HFRS), widely distributed in Asia and some parts of Europe. The focus of this Disease Tool however, is HPS.

Zoonotic disease: rodents, specific for each hantavirus (deer mouse for Sin nombre, white-footed mouse for New York, cotton rat for Black Creek, rice rat for Bayou and Andes Hantaviruses) carrying hantaviruses can shed the virus in their urine and faeces and can transmit it by biting.

Airborne spread: Breathing in the virus. This may happen when rodent urine and droppings containing hantavirus are stirred up into the air.

Vehicle-borne transmission:

• Hantavirus is transmitted to humans via contact with food or household items contaminated with rodent urine or faeces.
• Touching eyes, nose or mouth after touching rodent droppings, urine or nesting materials that contain the virus.
• A bite from an infected rodent can transmit the virus to humans.

Contact transmission: Close contact with individuals with HPS (for Andes virus in South America only).

7—42 days.

Andes virus is the only hantavirus for which person-to-person transmission has been proven. Person-to-person transmission of Andes virus occurs mainly in family clusters or, less commonly, after activities in which close contact with an infected patient has occurred.

• Early symptoms include fatigue, fever and muscle aches, especially in the large muscle groups (thighs, hips, back and sometimes shoulders). Further early symptoms include headache, chills, dizziness and gastrointestinal symptoms.
• Four to ten days after the initial phase appear coughing and shortness of breath, with the sensation of, as one survivor put it, a “tight band around my chest and a pillow over my face” as the lungs fill with fluid. The disease progresses rapidly, necessitating hospitalization and often ventilation within 24 hours. HPS can be fatal.

Acute respiratory distress syndrome (ARDS), pneumonia, plague, Q fever, anthrax, COVID-19 disease and other diseases.

• A positive serological test result.
• Evidence of viral antigen in tissue by immunohistochemistry, or the presence of amplifiable viral RNA sequences in blood or tissue, with compatible history of HPS.

Please refer to the appropriate local or international guidelines for clinical management. All clinical management including the administration of any treatment should be conducted by health professionals.

• There is no specific treatment, cure or vaccine for hantavirus infection. However, if infected individuals are recognized early and receive medical care in an intensive care unit, they may do better.
• In intensive care, patients are often intubated and given oxygen therapy to help them through the period of severe respiratory distress.
• Early symptoms regularly include gastrointestinal symptoms and therefore might require rehydration and monitoring the fluid balance.

Immune response towards hantaviruses is long-lasting.