It comes as medics around the world work to stop the spread of the outbreak linked to the luxury cruise ship MV Hondius, which travelled through the South Atlantic and stopped at several places.
Hantavirus is primarily spread by rodents but can be transmitted between people in rare cases, according to the World Health Organisation. It usually begins with flu-like symptoms, such as fatigue and fever, one to eight weeks after exposure.
The WHO has increased its tally of confirmed cases in the outbreak to nine. It said further cases could materialise because of the long incubation period, but that this was not a pandemic, and nothing like Covid-19.
The 12 will be quarantined for six weeks, the Radboudumc hospital in the city of Nijmegen said, adding that the infection risk was very low and patient care continued uninterrupted.
The quarantining of the medics illustrates the challenge of quickly introducing and implementing stricter protocols needed in hospitals and elsewhere for dealing with the hantavirus strain.
Meanwhile, the Hondius is making its way back to the Netherlands following the evacuation of all passengers, where it will be disinfected. Twenty-five crew as well as a doctor and a nurse are on board.
'POSSIBLE WE MIGHT SEE MORE CASES'
In addition to the nine confirmed cases, the WHO recognises two suspected cases - one person who died before being tested, and one on Tristan da Cunha, a remote South Atlantic island where there were no tests available. So far, all are considered to have been contaminated on the cruise trip, or before boarding the ship.
All suspected cases have been isolated and placed under strict medical supervision, minimising any risk of further transmission, WHO chief Tedros Adhanom Ghebreyesus said.
He warned more cases were to be expected as there had been "a lot of interaction" between passengers before hantavirus was detected.
"At the moment, there is no sign that we are seeing the start of a larger outbreak, but of course the situation could change and given the long incubation period of the virus, it's possible we might see more cases in the coming weeks."
All passengers who had disembarked the ship at earlier stages in the cruise had been located, Tedros said, adding it was up to their respective countries to implement protocols to prevent the virus from spreading.
TEST OF INTERNATIONAL COORDINATION
Italy's top infectious diseases hospital said it would examine biological samples from a man who had been in contact with a Dutch woman who died of hantavirus.
Arnaud Fontanet, head of Epidemiology of Emerging Diseases at France's Pasteur Institute, said the hunt for new cases could drag on for months, since the incubation time was up to six weeks. Still, because it does not transmit easily, his guess was that there would be no more than a few dozen more cases in total.
The crisis, though, "is a good way for us to try to test all that has been done since Covid-19," to check how international coordination works, he told Reuters.
Spain announced late on Monday that a Spaniard had tested positive, one of 14 quarantining at a military hospital in Madrid. It said on Tuesday that definitive tests had confirmed negative results for the 13 others in quarantine.
The confirmed cases also include a French passenger who tested positive after the ship docked in the Canary Islands on Sunday and was in intensive care but in a stable condition.
Britain says 10 people from remote island territories, including cruise ship passengers and medical staff who had contact with confirmed cases of hantavirus, will be brought to the United Kingdom for precautionary isolation.
The UK Health Security Agency said the individuals were already isolating and not showing symptoms. The people being transferred are British nationals from the overseas territories of Saint Helena island and Ascension Island.
According to the cruise company's website, 32 guests and one crew member disembarked from the vessel at Saint Helena and two guests had a medical evacuation via Ascension Island.
The governor of Saint Helena, Ascension and Tristan da Cunha said in a statement on Monday that resident medical staff on Ascension Island who had treated a confirmed case were being relocated to Britain as a precaution, with replacement clinicians flown in to maintain healthcare on the island.
In the United States, Department of Health and Human Services officials said on Monday that 18 passengers from the Hondius were flown back to the US and quarantined, with the one passenger who tested weakly positive now in a Nebraska biocontainment unit.
