Three travelers have died aboard the cruise ship Hondius, sailing from Argentina to Cape Verde, in an incident linked to a suspected hantavirus infection. Another traveler has tested positive; media report the 69-year-old is receiving intensive care in South Africa. Two crew members are also seriously ill. How and where they became infected is unclear. The WHO Regional Office for Europe said the risk to the general public remains low and that there is no reason for panic or travel restrictions. The ship is operated by Oceanwide Expeditions and currently has 149 passengers and crew aboard.
Hantavirus is a zoonotic disease transmitted from animals—primarily rodents—to humans. The viruses have also been found in shrews, moles and bats. Infected animals shed virus in saliva, urine and feces. Humans typically become infected by inhaling dust contaminated with these excretions (for example when dried droppings or nesting material are disturbed), by ingesting contaminated particles, or by touching the face after contact with contaminated material. The virus can survive in the environment for several weeks. Direct contact is not necessary, though an infected rodent bite can transmit the virus.
Person-to-person transmission is not generally observed in Europe. In South America, limited human-to-human transmission has been reported for the Andes virus (found in Argentina and Chile); however, studies have not definitively established sustained person-to-person spread.
Symptoms vary by virus strain. Strains in Europe and Asia often cause a flu-like illness with high fever, headache, abdominal and back pain; some infected people remain asymptomatic. In some cases the illness progresses to hemorrhagic fever with renal syndrome (HFRS), which can lead to low blood pressure, kidney dysfunction and acute kidney failure. Reported fatality rates for HFRS range from under 1% up to about 15%, depending on the strain.
In North and South America, certain hantaviruses can cause hantavirus pulmonary syndrome (HPS), characterized by fluid accumulation in the lungs, sudden drop in blood pressure and severe respiratory distress. HPS has a higher fatality rate—roughly 30% to 40% in reported series.
Hantaviruses are present in many countries. In Germany, between about 200 and 3,000 cases are reported annually. The most common strain there is Puumala virus, whose reservoir is the bank vole; mortality for Puumala infections is around 1%. Dobrava-Belgrade virus, carried by the striped field mouse, occurs mainly in eastern Germany and can cause more severe disease. The Seoul virus also causes occasional infections.
Long-term health consequences after hantavirus infection have been reported in recent studies: survivors face an elevated risk of certain blood cancers and cardiovascular disease in subsequent years, though mechanisms remain unclear.
There is no specific, widely available antiviral therapy for hantavirus; treatment is largely supportive. Severe cases may require dialysis for renal failure or mechanical ventilation for respiratory failure. No vaccines are currently licensed for use in Europe, North America or South America. Vaccines have been used in China and South Korea, but their protective efficacy is not clearly established in international studies. Research is ongoing: experimental therapies using antibodies from survivors have neutralized several hantavirus strains in initial trials, and DNA vaccine candidates targeting Puumala virus showed promising early human-trial results with findings published in late 2024.
This article was originally published in German.