NAIROBI, Kenya, May 8 — The World Health Organization (WHO) has issued updated information on hantaviruses, a group of viruses spread mainly by rodents that can cause severe illness in humans — including life-threatening lung and kidney complications.
What are hantaviruses?
Hantaviruses are zoonotic viruses, meaning they are naturally carried by animals and can sometimes spread to humans. The primary carriers are rodents such as rats and mice, which can carry the virus without appearing sick.
Humans typically become infected after exposure to infected rodents or their urine, droppings, or saliva.
The viruses belong to the Hantaviridae family and are found in different parts of the world, with disease patterns varying by region.
How do people get infected?
Transmission usually happens when people inhale tiny virus particles released into the air from dried rodent waste.
Common risk situations include:
Cleaning poorly ventilated rooms or cabins with rodent infestations
Farming or forestry activities
Sleeping in rodent-infested buildings
Handling contaminated materials
Exposure to rodent bites, although this is less common
WHO says the risk increases in enclosed spaces where rodent droppings accumulate.
Can hantavirus spread between people?
In most cases, no.
However, WHO notes that the Andes virus in South America is the only hantavirus known to cause limited human-to-human transmission. This has mainly been documented among close household contacts or intimate partners in countries such as Argentina and Chile.
Even then, transmission remains uncommon.
What diseases does hantavirus cause?
The illness caused by hantavirus depends on the region and virus type.
1. Hantavirus Cardiopulmonary Syndrome (HCPS)
Found mainly in the Americas, HCPS affects the lungs and heart and can rapidly become fatal.
Symptoms may begin like the flu but can worsen quickly.
Key signs include:
Fever
Headache
Muscle aches
Nausea or vomiting
Abdominal pain
Cough
Shortness of breath
Fluid buildup in the lungs
Shock in severe cases
WHO says HCPS can have a fatality rate of up to 50%.
2. Haemorrhagic Fever with Renal Syndrome (HFRS)
Common in Europe and Asia, HFRS mainly affects the kidneys and blood vessels.
Severe cases may cause:
Low blood pressure
Bleeding disorders
Kidney failure
How common is hantavirus?
Globally, hantavirus infections are considered relatively rare, but they remain a serious public health concern because of their high fatality rates.
WHO estimates between 10,000 and more than 100,000 infections occur each year worldwide.
Regional patterns
Asia and Europe: Thousands of HFRS cases are reported annually
China and South Korea: Continue to record large numbers of infections
Europe: Several thousand cases occur mainly in northern and central regions
The Americas: HCPS cases are much rarer, with only hundreds reported yearly
Countries in South America including Argentina, Brazil, Chile, and Paraguay report small numbers of infections annually, but severe disease remains a major concern.
Why is diagnosis difficult?
Early hantavirus symptoms resemble many other illnesses, including:
Influenza
COVID-19
Viral pneumonia
Dengue
Leptospirosis
Sepsis
Because of this, doctors rely heavily on patient history, especially possible rodent exposure, travel history, or occupational risks.
Laboratory testing may include:
Antibody tests
RT-PCR testing to detect viral genetic material
WHO warns that patient samples pose a biohazard risk and require strict laboratory containment measures.
Is there a cure or vaccine?
Currently, there is:
No licensed antiviral treatment
No approved vaccine for widespread use
Treatment focuses on supportive care, including:
Oxygen support
Intensive care monitoring
Management of heart, lung, and kidney complications
WHO stresses that early medical care greatly improves survival chances, especially in severe HCPS cases.
How can people protect themselves?
Prevention mainly centres on avoiding contact with rodents and contaminated environments.
WHO recommends:
Keeping homes and workplaces clean
Sealing holes where rodents can enter
Storing food securely
Practising proper hand hygiene
Wetting contaminated areas before cleaning
Avoiding dry sweeping or vacuuming rodent droppings, which can release virus particles into the air
What happens during outbreaks?
During suspected outbreaks, health authorities may:
Isolate suspected cases
Monitor close contacts
Strengthen infection prevention measures
Increase public awareness campaigns
Hospitals are advised to apply strict infection prevention and control procedures, especially during aerosol-generating medical procedures.
WHO’s role
WHO says it is working with countries and partners to improve:
Disease surveillance
Laboratory testing capacity
Early detection systems
Public communication
Patient care and outbreak response
The agency is also promoting a “One Health” approach, which recognises the connection between human health, animal health, and environmental conditions in preventing disease outbreaks.