Three passengers have died and several others are seriously ill on the cruise ship Hondius, which sailed from Argentina toward Cape Verde, in an episode linked to a suspected hantavirus infection. One traveler has tested positive and, according to media reports, a 69-year-old patient is receiving intensive care in South Africa. Two crew members are reported as seriously ill. How and where they contracted the infection has not been established. The WHO Regional Office for Europe said the risk to the general public is low and that there is no reason for panic or travel restrictions. The vessel, operated by Oceanwide Expeditions, currently has 149 people on board including passengers and crew.
What hantavirus is
Hantaviruses are a group of zoonotic viruses carried mainly by rodents, though related viruses have been found in shrews, moles and bats. Infected animals release virus in saliva, urine and feces. Humans most commonly become infected when contaminated material is disturbed and virus-containing dust is inhaled, but infection can also occur by ingesting contaminated particles or by touching the face after contact with contaminated surfaces. The virus can remain infectious in the environment for several weeks. Direct contact with an infected animal is not required, although a rodent bite can transmit infection.
Person-to-person spread
Person-to-person transmission is uncommon. In Europe and Asia it is not generally seen. Limited human-to-human transmission has been reported for the Andes virus in Argentina and Chile, but sustained person-to-person spread has not been definitively demonstrated in studies.
Symptoms and severe disease
Clinical presentation varies by hantavirus species. Infections from strains common in Europe and Asia often begin with non-specific, flu-like symptoms such as high fever, headache, abdominal and back pain; some infected people have no symptoms. A proportion of cases progress to hemorrhagic fever with renal syndrome (HFRS), which can cause low blood pressure, impaired kidney function and acute kidney failure. Reported fatality rates for HFRS depend on the specific virus and range from under 1% to about 15%.
In the Americas some hantaviruses cause hantavirus pulmonary syndrome (HPS), a distinct and often severe illness marked by rapid fluid accumulation in the lungs, a sudden drop in blood pressure and severe respiratory distress. HPS has been associated with higher mortality in reported series, typically around 30–40%.
Where hantaviruses occur
Hantaviruses are found worldwide in many countries. For example, Germany reports roughly 200 to 3,000 cases per year, with the Puumala virus (carried by the bank vole) the most common strain there; Puumala infections have a mortality near 1%. The Dobrava-Belgrade virus, associated with the striped field mouse, is seen mainly in eastern regions and can cause more severe disease. The Seoul virus also causes occasional infections and has a global distribution linked to rats.
Long-term effects
Recent studies suggest that survivors of hantavirus infection may face an elevated risk in later years of certain blood cancers and cardiovascular disease, though the biological mechanisms behind those associations remain unclear.
Treatment and prevention
There is no specific, widely available antiviral treatment for hantavirus infections; clinical care is supportive. Patients with severe kidney involvement may need dialysis, and those with respiratory failure can require mechanical ventilation. No vaccines are licensed for general use in Europe, North America or South America. Vaccines have been used in China and South Korea, but their effectiveness has not been clearly established in international studies.
Research directions
Research continues on treatments and vaccines. Experimental therapies using antibodies from recovered patients have shown the ability to neutralize several hantavirus strains in early trials. DNA vaccine candidates aimed at Puumala virus produced promising results in initial human trials, with findings published in late 2024.
Summary
The incident aboard the Hondius has raised concern and is under investigation, but health authorities say the public risk is low. Hantavirus infections arise from contact with infected small mammals or their excreta, cause a range of illness from mild flu-like symptoms to severe renal or pulmonary disease depending on the virus, and are managed primarily with supportive care. Ongoing research aims to improve prevention and treatment options.
This article was originally published in German.