How Worried Should We Be About Hantavirus? Experts Weigh the Risk

When the cruise ship outbreak was confirmed, some passengers had already flown on to several countries. The UK Health Security Agency said anyone returning from the trip with suspicious symptoms is being directed to specialist testing. The Dutch public-health institute RIVM said three people evacuated from the ship are being monitored in intensive care.

Professor Olivia Veit, an epidemiologist at the London School of Hygiene and Tropical Medicine, said hantavirus has historically caused localised, rodent-driven outbreaks. "Rare person-to-person transmission of the Andes strain has been documented in clusters of relatives and health-care workers in Chile, but the potential for wide international spread is low," she said. The U.S. CDC says hantavirus pulmonary syndrome has an overall fatality rate of about 38 percent, although early diagnosis can substantially improve outcomes.

The World Health Organization has asked travellers linked to the ship to monitor themselves for symptoms during the 42-day incubation period. The European Centre for Disease Prevention and Control said the risk to the general public remains low. Experts urge calm but say anyone who disembarked should seek medical advice promptly if they develop fever, muscle pain or breathlessness.