The World Health Organization on Thursday declared the hantavirus outbreak aboard the expedition cruise ship MV Hondius over, after the last identified contact completed a 42-day quarantine, tested negative and returned home. No new cases have been reported since 25 May, WHO Director-General Tedros Adhanom Ghebreyesus told a Geneva press conference, closing a two-month international health alert that traced more than 650 contacts across 33 countries and territories.

The cluster, which produced 12 confirmed and one probable case including three deaths, was caused by the Andes virus — the only known hantavirus strain capable of limited human-to-human transmission. The Dutch-flagged vessel had departed Ushuaia, Argentina, on 1 April with 175 people aboard, calling at remote South Atlantic islands before the outbreak forced an evacuation of passengers at Tenerife, Spain, on 10 May. The ship finally docked in Rotterdam on 18 May, where a reduced crew remained in quarantine for weeks. Argentine health authorities announced in June that an investigation in a second province had failed to identify virus-carrying rodents, leaving the initial source of infection unconfirmed.

Viewed from Geneva, the declaration marks a shift from emergency response to scientific investigation. The WHO is coordinating a study involving 21 countries to understand how the disease develops, which Tedros said would support the development of diagnostics, therapeutics and vaccines. Diana Rojas Alvarez, the agency’s high-impact epidemics chief, noted that while the Hondius outbreak no longer posed a public health risk, the Andes virus and other hantaviruses remain a threat in endemic areas of South America. Health authorities in Nigeria, which maintained surveillance throughout the alert, confirmed no cases were detected in the country.

The next institutional milestone is the completion of the Pandemic Agreement later this month, which the WHO hopes the episode will spur member states to finalise. Meanwhile, the multinational study into hantavirus pathogenesis is in its early stages, with no timeline yet announced for initial findings.