Two cases of hantavirus have been confirmed after three people died and a UK national was left seriously ill following a suspected outbreak on a cruise ship in the Atlantic Ocean.

The operator of the MV Hondius ship, Oceanwide Expeditions, said a Dutch husband and wife, as well as a German national, had died.

Hantavirus has been confirmed in the case of the 69-year-old UK national who is in intensive care in a hospital in South Africa, and was present in the Dutch woman who died. The causes of the deaths of the other passengers are being investigated.

Hantavirus is usually spread from rodents via their faeces, saliva or urine. It can cause severe respiratory illness.

It is rarely transmitted between people.

As well as the UK national who has been confirmed as having hantavirus, a British crew member is among a further five suspected cases linked to the ship being investigated by the World Health Organization (WHO).

The MV Hondius vessel is currently off the coast of Cape Verde and has 149 people onboard from 23 countries.

"The atmosphere on board MV Hondius remains calm, with passengers generally composed," Oceanwide Expeditions said.

It added there are two crew members - one British and one Dutch - are on board "with acute respiratory symptoms, one mild and one severe", but hantavirus had not been confirmed in the pair.

They both require urgent medical care, it said. No other people aboard have shown symptoms.

Dutch authorities are "actively preparing" for a medical evacuation of the two crew members, as well as a person "associated" with the German national who died, Oceanwide Expeditions said.

"This will involve two specialised aircraft equipped with the necessary medical equipment and staffed by trained medical crews," it said.

Negotiations are in progress with local authorities following what Oceanwide Expeditions described as "a serious medical situation".

Outlining a timeline, the company said a passenger had become unwell while aboard and died on 11 April.

His cause of death could not be determined, and his body was taken off the ship after it docked at St Helena on 24 April.

The passenger's wife also disembarked on St Helena and the firm said it was told she had become unwell during the return journey and later died.

On 27 April, the firm said, another passenger - the British national - became seriously ill and was "medically evacuated" to South Africa.

The 69-year-old remains in a critical but stable condition in Johannesburg after it was confirmed a variant of hantavirus had been identified.

The firm added that on Saturday, a third passenger onboard MV Hondius died.

The cause of death has not been established, Oceanwide Expeditions said. It confirmed the passenger was German.

Dr Aaron Motsoaledi, South Africa's minister of health, said of the British patient that he was critical and had been admitted to a private facililty.

"He's being taken care of. As you know, hantavirus, like all viruses, don't have any specific treatment, so they are giving symptomatic treatment and support as much as they could."

He said health workers and anyone who had contact with the patient would now be traced and tested.

A UK government spokesperson said the foreign office was in touch with the man's family and that consular teams were operating in the UK, South Africa, Spain and Portugal to support British nationals.

Oceanwide Expeditions said the option of sailing to Las Palmas or Tenerife was being considered "to be the gateway for disembarkation, where further medical screening and handling could take place".

The WHO said it was "acting with urgency" to support the MV Hondius, and thanked South African authorities for taking care of the British patient.

WHO's regional director for Europe, Dr Hans Henri P Kluge, said "hantavirus infections are uncommon".

"While severe in some cases, it is not easily transmitted between people. The risk to the wider public remains low. There is no need for panic or travel restrictions."

According to the South African government, MV Hondius departed from Ushuaia in southern Argentina about three weeks ago, before it completed its journey to Cape Verde, where it is anchored outside the capital, Praia.

It is described as a 107.6m (353ft) polar cruise ship, with space for 170 passengers in 80 cabins, along with 57 crew members, 13 guides and one doctor.

One passenger onboard the MV Hondius, who asked to remain anonymous, told the BBC: "The latest word is that a plane is on its way and once it gets here three people will be evacuated from the ship and flown straight to Europe.

"Then the rest of us will almost certainly sail to the Canary Islands.

"The Cape Verde authorities clearly want nothing to do with us. This is what we're hearing from the captain and staff. From what I can see the mood (on the ship) is pretty good.

"Only one person has been tested (the one now in South Africa) and he tested positive for hantavirus. So, we don't actually know yet if the other cases are that or something unrelated.

"If they are all hantavirus then the transmission is a bit mysterious. We've been informed that there are no rodents on board, and person-to-person transmission is difficult/rare.

"Hopefully the other patients on board will be tested soon and then we'll know better what's going on."

President of the Cape Verdean Public Health Institute, Maria Da Luz, said passengers would not be disembarking in Cape Verde in order to protect the local population, Cape Verde's media outlet A Nacao reports. (BBC)

Update news