A deadly outbreak of the rare hantavirus unfolded over the course of weeks on a cruise ship that sailed from Argentina toward Antarctica and then across the Atlantic Ocean, stopping at or near remote islands on the way as passengers and crew members fell sick.
The outbreak can be traced from information released by the cruise operator, the World Health Organisation and ship tracking data.
The available information shows nearly a month passed between when an elderly Dutch man fell sick and died in the South Atlantic, and laboratory tests in South Africa — more than 3500km away — confirmed hantavirus infections.
Three passengers in total have died, one is in intensive care in a South African hospital, and three other people still on the cruise ship have shown symptoms and are waiting for evacuations.
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Nearly 150 passengers and crew members from 23 countries were on the ship, which is waiting off the coast of West Africa. One New Zealander is on board, according to MFAT.
Hantavirus is spread by rodents. People can get it through contact with infected rodents' saliva, urine or droppings. It doesn’t usually spread from person to person, but some health authorities say such transmission could be possible.
While only two hantavirus cases related to the ship have been confirmed through tests, the World Health Organisation (WHO) suspects the others are also hantavirus and is treating it as an outbreak. It is still investigating the source.
What happened on the ship
The Dutch company that operates the ship, the MV Hondius, offers “expedition cruises” that involve trips to the Antarctic and several islands in the South Atlantic to see some of the remotest places on earth.
The cruises can last a month or more and cost between US$6000 and US$25,000 (NZ$10,000 and NZ$42,000), depending on the cabin.
The MV Hondius set off from southern Argentina on April 1.
On April 6, the 70-year-old Dutch man fell ill with fever, headache and mild diarrhoea, WHO said. He died on board on April 11, after developing respiratory distress.
The ship was between the British island territories of South Georgia and St Helena in the middle of the South Atlantic, according to data from the ship tracking website MarineTraffic.
The cause of death could not be determined, according to the cruise company, Oceanwide Expeditions.
The ship sailed on for nearly two weeks, stopping near the island of Tristan da Cunha before it reached St Helena, where the Dutch man's body was taken off the ship on April 24.
His 69-year-old wife disembarked with his body and flew to South Africa, while the man's body remained behind.
The woman, who already had symptoms, became sicker during the April 25 flight and collapsed at an airport in South Africa. She died at a hospital on April 26, WHO said.
Another passenger, a British man, became sick on the ship after it left St Helena and sailed to tiny Ascension Island, some 1300km north.
He had a high fever, shortness of breath and signs of pneumonia, according to WHO, and was evacuated from Ascension Island to South Africa on April 27. He is in an intensive care unit in a South African hospital.
The third fatality, a German woman, died on the ship on Saturday, again after it had set sail for a new destination — this time Cape Verde.
She died four days after falling ill and also had signs of pneumonia, WHO said, which can be caused by hantavirus. Her body is still on the ship.
When authorities first knew hantavirus was on the ship
Health officials in South Africa ultimately tested the British man in intensive care for hantavirus after other extensive tests on him were negative. They received a positive result for hantavirus on Saturday (local time) some 21 days after the first passenger died.
On Sunday, WHO announced it was investigating a suspected hantavirus outbreak on the ship, which had by that time reached Cape Verde waters.
The British man's positive test prompted South African health authorities to also test the Dutch woman's body posthumously for hantavirus.
That test came back positive on Monday.
WHO said the outbreak on the ship was being managed and the global risk was low as hantavirus is not easily spread between people, although it added it was tracing people who were on a passenger plane between St Helena and Johannesburg, South Africa, with the Dutch woman.
What the plan is for the people still on board
Oceanwide Expeditions said aircraft were flying to Cape Verde to evacuate two people needing urgent medical care and one passenger who was travelling with the German woman who died Saturday.
They were to be taken to the Netherlands, but a timeline for arrival wasn’t clear.
The ship then would sail to Spain’s Canary Islands, a voyage of about three days, the company said.
Spanish officials had said they were monitoring the situation and hadn’t confirmed any plans as of Tuesday evening (local time).
Passengers and crew have been isolated in cabins with "maximal physical distancing", WHO said, in a lockdown reminiscent of the Covid-19 pandemic.
WHO says it is still investigating how a virus that is relatively rare in people got on board the ship. It said the Dutch man and his wife — whom it called cases one and two — had travelled in Argentina and elsewhere in South America before they boarded.
WHO says the Andes virus, a specific species of hantavirus, is found in South America, primarily in Argentina and Chile.
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