On May 2, 2026, a cruise ship carrying 147 passengers and crew reported cases of severe respiratory illness aboard the ship.
As of May 4, 2026, the World Health Organisation (WHO) said seven cases (two laboratory-confirmed hantavirus cases and three suspected cases) had been identified.
These cases include three deaths, one critically ill patient, and three individuals reporting mild symptoms.
While the WHO has assessed the global risk from the current situation as low, understanding how the virus works, how it spreads, and why it can be severe is important.
What is Hantavirus?
The WHO describes Hantaviruses as zoonotic viruses that naturally infect rodents and are occasionally transmitted to humans. Infection in people can result in severe illness and often death. The disease varies by virus type and geographical location.
Hantaviruses belong to the family Hantaviridae, within the order Bunyavirales. Each hantavirus is typically associated with a specific rodent reservoir species, in which the virus causes long‑term infection without apparent illness.
Although many hantavirus species have been identified worldwide, only a limited number are known to cause human disease.
Transmission
Transmission of hantaviruses to humans occurs from contact with contaminated urine, droppings or saliva of infected rodents. Infection may also occur, although less commonly, through rodent bites. Activities that involve contact with rodents, such as cleaning enclosed or poorly ventilated spaces, farming, forestry work and sleeping in rodent-infested dwellings, increase exposure risk.
To date, human-to-human transmission has been documented only for the Andes virus in the Americas and remains uncommon. When it occurs, transmission between people has been associated with close and prolonged contact, particularly among household members or intimate partners. It appears most likely during the early phase of illness, when the virus is more transmissible.
Symptoms
In humans, symptoms usually begin between one and eight weeks after exposure, depending on the virus type, and typically include fever, headache, muscle aches, and gastrointestinal symptoms such as abdominal pain, nausea, or vomiting.
Diagnosis
Early diagnosis of hantavirus infection can be challenging because early symptoms overlap with those of other febrile or respiratory illnesses, such as influenza, COVID-19, viral pneumonia, leptospirosis, dengue, or sepsis. So a careful patient history is therefore essential, with particular attention to possible rodent exposure, occupational and environmental risks, travel history, and contact with known cases in areas where hantaviruses are present.
Laboratory confirmation relies on serological testing to detect hantavirus-specific IgM antibodies or rising IgG titres, as well as molecular methods such as reverse transcription polymerase chain reaction (RT-PCR) during the acute phase of illness, when viral RNA may be detectable in blood.
Samples collected from patients are a biohazard risk; laboratory testing on non-inactivated samples should be conducted under maximum biological containment conditions. All non-inactivated biological specimens should be packaged using the triple packaging system when transported nationally and internationally.
Treatment
There is no licenced specific antiviral treatment or vaccine for hantavirus infection. Care is supportive and focuses on close clinical monitoring and management of respiratory, cardiac and kidney complications. Early access to intensive care, when clinically indicated, improves outcomes, particularly for patients with hantavirus cardiopulmonary syndrome.
Prevention and control
Preventing hantavirus infection largely depends on reducing contact with rodents and contaminated environments. Health experts recommend keeping homes and workplaces clean, sealing openings that may allow rodents to enter buildings, and storing food securely to avoid attracting pests.
When cleaning areas that may be contaminated with rodent urine or droppings, people are advised to avoid dry sweeping or vacuuming, as this can release infectious particles into the air. Instead, contaminated surfaces should be dampened before cleaning to reduce the risk of inhaling harmful particles.
People are also advised to practice proper hand hygiene as an important preventive measure.
During outbreaks or when hantavirus infection is suspected, public health authorities emphasise the importance of early detection and prompt isolation of infected individuals. Monitoring people who have had close contact with suspected or confirmed cases can help health officials respond quickly to any new infections.
In healthcare and community settings, applying standard infection prevention and control measures is essential to reducing the risk of further spread and protecting vulnerable populations.
Infection prevention and control
Available evidence indicates that the risk of healthcare-associated transmission of hantavirus, including Andes virus, is very low when appropriate infection prevention and control measures are applied. In health-care environments, standard precautions should be applied for all patients, including hand hygiene, environmental cleaning and safe handling of blood and body fluids.
For suspected or confirmed hantavirus infection, use standard precautions, combined with transmission-based precautions, during care. For aerosol-generating procedures, airborne precautions should be used. Early recognition of suspected cases, prompt isolation, and consistent adherence to recommended infection prevention and control measures remain essential to protect health-care personnel.
Difference between Hantavirus and Lassa fever
Although Hantavirus Pulmonary Syndrome and Lassa fever are both rodent-borne viral diseases that can cause severe illness in humans, they differ in the viruses that cause them, their symptoms, transmission patterns, and the organs they mainly affect.
Hantavirus mainly attacks the lungs, causing severe breathing problems and pneumonia, while Lassa fever can affect multiple organs and may cause bleeding in severe cases.
Hantavirus is rarely transmitted from person to person, whereas Lassa fever can spread through contact with bodily fluids, especially in hospitals or caregiving settings.
Another key difference is location. Lassa fever is common in West African countries like Nigeria and causes seasonal outbreaks, while hantavirus cases are rarer and occur in different regions worldwide depending on the rodent species involved.
Both diseases are primarily spread through contact with rodent urine, saliva, or droppings, making good hygiene and rodent control important for prevention.
Conclusion
Although the current global risk remains low, the incident highlights the importance of early detection, proper infection prevention measures, and public awareness about diseases that can spread through contact with infected rodents.