WHO declares cruise-linked hantavirus outbreak over

The World Health Organization has declared the hantavirus outbreak linked to a cruise ship over after 13 infections, three deaths and contact tracing that reached more than 650 people across 33 countries and territories.

WHO Director-General Dr Tedros Adhanom Ghebreyesus said Thursday that the last identified contact of a person exposed to hantavirus on the MV Hondius had completed quarantine, tested negative and returned home.

“Today, the final contact of a person exposed to hantavirus on the cruise ship MV Hondius completed their quarantine period, tested negative and returned home,” Tedros said. “No further cases have been reported since the 25th of May. Therefore, WHO considers the hantavirus outbreak over.”

The outbreak involved the Andes virus, a rare hantavirus strain that typically circulates in Argentina and Chile. The MV Hondius, a Dutch-flagged polar exploration ship, set off from Ushuaia, Argentina, on April 1. Al Jazeera reported that the ship traveled to remote islands in the South Atlantic Ocean, including Tristan da Cunha, before heading north to Tenerife in Spain’s Canary Islands, where remaining passengers were flown home. The ship later docked in Rotterdam, Netherlands, on May 18 and, after cleaning and disinfection, was cleared to sail again on May 30, Al Jazeera reported.

The WHO had previously said the first two cases had traveled through Argentina, Chile and Uruguay on a bird-watching trip that included sites where the rat species known to carry the virus was present. Hantaviruses usually spread from rodents to people, often when someone breathes air contaminated with virus particles from rodent urine, droppings or saliva. Infection can also occur through contact with rats, mice or their waste, and the virus can become airborne during cleaning of infested areas.

Health experts believe the virus may also have passed between people who were in close contact during this outbreak. The Andes virus is the only known hantavirus that can spread through close, prolonged human-to-human contact.

Symptoms can include fever, extreme fatigue, headache, muscle aches, stomach pain, nausea, vomiting, diarrhea and shortness of breath. They typically appear two to four weeks after exposure, though Al Jazeera reported they can occur between one and eight weeks after exposure, and the BBC reported symptoms can appear more than a month later. That long incubation period was why authorities recommended an extended isolation period for passengers.

In severe cases, the illness can progress quickly to coughing, shortness of breath and fluid buildup in the lungs. Al Jazeera reported that there are no approved vaccines or targeted antiviral treatments for the disease, and care remains largely supportive.

Tedros said the WHO would continue working with governments and partners to understand the outbreak and the virus. “We are also coordinating a study involving 21 countries to understand how the disease develops, which will support the development of diagnostics, therapeutics and vaccines for future outbreaks,” he said.

WHO medical officer Dr Diana Rojas Alverez said continued vigilance remains necessary. “Andes virus and other hantaviruses are still a public health risk for South America, and some other endemic areas,” she said at a briefing. “What we need to continue doing is to keep monitoring this virus, keep preparing for further spread.”