An outbreak of hantavirus on a cruise ship has put the virus in the spotlight, six years after the start of the COVID-19 pandemic, raising fears of the resurgence of a serious global epidemic.
The rodent-borne disease can cause acute respiratory syndrome, but is far less contagious than other viruses, such as COVID-19 or measles.
There isn’t just one type of hantavirus, but several
Different types of hantavirus are transmitted to humans through infected wild rodents, such as mice or rats, which shed the virus in their saliva, urine, and faeces. A bite, contact with these rodents or their droppings, or inhalation of contaminated dust can cause infection.
Although thousands of hantavirus cases are observed each year, hantavirus infections are relatively rare worldwide.
The World Health Organization (WHO) states in its fact sheet on hantaviruses that in the Americas, hantaviruses can cause hantavirus cardiopulmonary syndrome (HCPS), a severe respiratory illness with a case fatality rate of up to 50% (…). In Europe and Asia, hantaviruses cause hemorrhagic fever with renal syndrome (HFRS).”
In 2025, in the WHO Region of the Americas, eight countries reported 229 cases and 59 deaths, with a case fatality rate of 25.7%. In the WHO European Region, which is much larger than the European Union, 1,885 hantavirus infections were reported in 2023 (0.4 infections per 100,000 people), the lowest rate observed between 2019 and 2023.
In East Asia, particularly in China and the Republic of Korea, hantavirus hemorrhagic fever with renal syndrome (HHFRS) continues to account for several thousand cases each year, although such incidents have declined over the past few decades.
The Andean strain
Unlike other hantaviruses, this strain is the only one capable of documented human-to-human transmission, causing severe pulmonary syndromes with a case fatality rate of up to 50%.
The cases detected among people aboard the MV Hondius were Andean strain hantaviruses.
According to the WHO, this strain is primarily found in Argentina and Chile. An outbreak was identified in Argentina in 2018 in the town of Epuyén (Chubut province in Patagonia) following a birthday party. It infected 34 people and caused 11 deaths.
Symptoms and treatment
The first clinical symptoms are usually those of the flu: fever, headache, muscle aches, and gastrointestinal symptoms such as abdominal pain, nausea, or vomiting.
In hantavirus pulmonary syndrome (HPS), the illness can rapidly progress to cough, shortness of breath, pulmonary oedema, and shock.
In hemorrhagic fever syndrome with renal fever (HFRF), more advanced stages may include hypotension, clotting disorders, and kidney failure.
There is no vaccine or specific antiviral treatment for hantavirus, making prevention the most effective measure.
Limited contagion
The WHO has called for calm and ruled out the risk of a global epidemic similar to that of COVID-19. The risk of contagion depends on close proximity, “practically nose-to-nose,” a WHO spokesperson in Geneva stated.
The WHO specified that “the wife whose infected husband is being treated in a Swiss hospital “has not presented any symptoms and is self-isolating…So that shows you, again, luckily, apparently the virus is not that contagious.”
Similarly, the Dutch flight attendant who had been in contact with a passenger on the ship, who subsequently died, tested negative for hantavirus.
The strict application of public health measures – contact tracing, isolation of exposed individuals and cooperation between States – can break the chain of transmission, the WHO has explained repeatedly.