More cases of a deadly, rodent-borne illness could emerge in the coming weeks but the risk to public health is "low", according to the World Health Organisation.
Cases of hantavirus, the term for a group of viruses carried by infected rodents that can pose a severe disease risk in humans, emerged on luxury cruise ship MV Hondius last month.
The vessel had been marooned in quarantine off the coast of Cape Verde in West Africa since Sunday.
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WHO director general Dr Tedros Adhanom Ghebreyesus said eight cases of the Andes strain of the virus have been reported so far, including three deaths.
Five of the eight cases have been confirmed as Hantavirus, while the other three are suspected.
"Given the incubation period of the Andes virus, which can be up to six weeks, it's possible that more cases may be reported," Ghebreyesus said in the latest briefing.
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"While this is a serious incident, WHO assesses the public health risk as low.
"It's possible that more cases may be reported."
Ghebreyesus said the first two people with the confirmed virus had travelled through Argentina, Chile and Uruguay on a bird-watching trip.
He said the excursion included visits to sites where "the species of rat known to carry the virus was present".
The first case was in a man who developed symptoms on April 6 and died on the ship on April 11.
No samples were taken, and because his symptoms were similar to those of other respiratory diseases, Hantavirus was not suspected.
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The man's wife, who was also symptomatic, went ashore when the ship docked at the island of Saint Helena.
She deteriorated on the flight to Johannesburg on April 25 and died the next day.
Samples were taken, which was taken to South Africa's National Institute for Communicable Diseases.
Ghebreyesus said the third death was a woman on the ship who developed symptoms on April 28 and died on May 2.
Another man, who remains in intensive care, presented to the ship's doctor on April 24.
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Doctors boarded the ship to provide care for the three other passengers.
Two are in a stable condition and one is asymptomatic in Germany .
The eighth man disembarked at Saint Helena and reported himself with symptoms in Zurich, Switzerland.
No remaining passengers or crew on the ship are currently symptomatic, according to Ghebreyesus.
"WHO is aware of reports of other people with symptoms who may have had contact with one of the passengers," he said.
"In each case we're in close contact with the relevant authorities.
The cruise ship is now sailing to the Canary Islands following a request by the WHO to Spain.
"We're confident in the capacity of Spain to monitor the risk and we're supporting them to do so," Ghebreyesus said.
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