There are now five confirmed hantavirus cases from the Atlantic cruise ship outbreak, with three more suspected, the World Health Organization (WHO) said on Thursday, warning more cases are possible.
The WHO said it expected the outbreak on the MV Hondius, currently sailing from Cape Verde to the Spanish island of Tenerife, to be limited, so long as public health measures were properly implemented.
"So far, eight cases have been reported, including three deaths. Five of the eight cases have been confirmed as hantavirus and the other three are suspected," WHO Director-General Tedros Adhanom Ghebreyesus said.
"The species of hantavirus involved in this case is the Andes virus, which is found in Latin America," he told journalists in Geneva.
"Given the incubation period of the Andes virus, which can be up to six weeks, it's possible that more cases may be reported," he added.
The Dutch-flagged ship left Ushuaia in Argentina on April 1 on its cruise north through the Atlantic Ocean to Cape Verde. It set sail north toward Tenerife on Wednesday.
Tedros said he had been in regular contact with the ship's captain.
"He told me morale has improved significantly since the ship started moving again. I thank him for everything he has done to protect those under his duty of care," he said.
The WHO's emergency alert and response director, Abdi Rahman Mahamud, added: "We believe this will be a limited outbreak if the public health measures are implemented and solidarity shown across all countries."
The rare disease is usually spread from infected rodents, typically through urine, droppings and saliva.
The Andes virus is found in South America. It is the only strain of hantavirus with documented human-to-human transmission.
Tedros said Argentina would send 2,500 diagnostic kits to laboratories in five countries.
After leaving Ushuaia on its Atlantic voyage, the exploration vessel stopped at several remote islands along the way.
The WHO said it had informed 12 countries that its nationals had disembarked the MV Hondius on Saint Helena.
The ship called at the British territory from April 22 to 24. Its operator said that 30 guests had disembarked at that point, including the first fatality, a Dutchman who died on April 11.
The 12 countries were Britain, Canada, Denmark, Germany, the Netherlands, New Zealand, Saint Kitts and Nevis, Singapore, Sweden, Switzerland, Türkiye and the United States, Tedros said.