The World Health Organization (WHO) on Monday said the Andes hantavirus linked to the deadly outbreak aboard the Dutch-flagged cruise ship MV Hondius is most infectious during the initial stage of illness, underlining the need for strict quarantine measures for passengers and crew.The rare virus outbreak on the ship has so far claimed three lives and triggered international concern as passengers evacuated from the vessel return to multiple countries.“The first few moments of illness is when the infectiousness is highest,” Olivier Le Polain, head of WHO’s epidemiology and analytics for response division, said during a social media briefing, according to AFP.The WHO has advised that all nearly 150 people who were onboard the ship when it arrived near Tenerife on Sunday should undergo quarantine for six weeks.The recommendation is based on the incubation period of the Andes virus — the only known hantavirus strain capable of limited human-to-human transmission — which can extend up to 42 days.According to the WHO, infected individuals typically begin developing symptoms after around three weeks on average, though the virus can remain dormant for longer periods.Le Polain stressed that authorities should not wait for symptoms to emerge before isolating potential contacts.“If WHO recommends quarantine, it is because people are infectious at the very start of illness,” he said, noting that early symptoms are often mild and difficult to identify.Initial signs of infection can include fatigue, mild fever and body aches before rapidly progressing in some cases into severe respiratory illness.The WHO official warned that more infections linked to the cruise ship outbreak could still emerge over the coming days or even weeks due to the virus’s long incubation period.“That’s why we need to remain vigilant and make sure that the first signs and symptoms are recognised, isolated and treated,” he said.While the WHO issues broad public health recommendations, individual countries are deciding their own containment measures for returning passengers.Several countries, including Germany, Britain, Switzerland and Greece, have opted for 45-day quarantines for passengers linked to the ship. Australia and France have announced shorter observation periods of three weeks and two weeks respectively, with provisions for extension if required.The United States, however, has indicated that the 17 American passengers returning from the cruise may not necessarily be quarantined — a move WHO chief Tedros Adhanom Ghebreyesus cautioned “may have risks”.Le Polain said the cruise ship environment likely contributed to the spread of infection.“It’s an environment where people live together in a fairly enclosed space,” he said, adding that such conditions were conducive to transmission.The Andes hantavirus is a rare but potentially deadly viral disease that can cause hantavirus cardiopulmonary syndrome, a severe respiratory infection with high fatality rates in serious cases.
