The MV Hondius is currently unable to dock to let passengers disembark until the exact strain of the hantavirus is identified and an evacuation plan is drawn up.Getty

The MV Hondius was travelling from Argentina to the Cape Verde islands near west Africa when three passengers passed away and two crew members became seriously ill.

The ship is currently unable to dock to let passengers disembark until the exact strain of the virus is identified and an evacuation plan is drawn up.

A spokesman for Ireland's Department of Foreign Affairs stated on Monday that it "is providing consular assistance" after the ship's operator confirmed that two Irish people were among the 23 nationalities on board.

In a statement, cruise operator Oceanwide Expeditions said that two crew members require urgent medical care and are displaying acute respiratory symptoms, one mild and one severe.

Hantavirus is usually transmitted to humans from rodents and can cause respiratory and cardiac distress.

Fatality rates from the pathogen vary around the world but some strains are deadly in up to 40% of cases.

A Dutch passenger died aboard the ship over three weeks ago, on April 11, and was removed from the Hondius on April 24 when it docked at the island of St Helena in the South Atlantic Ocean, Oceanwide Expeditions said.

The passenger's wife disembarked with his body, and three days later, the ship was informed that the woman had also passed away.

Irish woman Ann Lane is currently aboard the ship and stated on Monday that the passengers are staying calm because "we can't really do anything at the moment".

Speaking to The Irish Times, Ms Lane said: "Now the ship's doctor and a member of the expedition staff are sick on board. The doctor had been treating everybody day and night, really dedicated to what he was doing.

"He has been sick quite a few days, maybe since last Thursday. The real shock was when the first people died because we just didn't know what this was."

Ms Lane said the news of the death of the Dutch couple, aged 70 and 69, was an "awful shock".

She continued: "Then another person died, a woman, and her body is still on the ship. It's terribly sad, really awfully sad."

US travel blogger Jake Rosmarin, who is on the boat, released a tearful plea for support, telling his 44,000 followers on Instagram: "We're not just a story, we're not just headlines, we're people."

The content creator from Boston added: "There's a lot of uncertainty, and that's the hardest part."

Oceanwide Expeditions said in a statement that it's unconfirmed whether the two deaths are connected to hantavirus until testing can be carried out. "On April 27, another passenger became seriously ill and was medically evacuated to South Africa," the statement said.

 "This person is currently being treated in the intensive care unit in Johannesburg and is in a critical but stable condition. This passenger is of British nationality. A variant of hantavirus has been identified in this patient.

"On Saturday, May 2, another passenger on board died. The cause has not yet been established. This passenger was of German nationality."

Medical evacuation requires permission from local health authorities at Cape Verde, which is 650km west of the African coast.

The tour operator stated that it is working closely with international authorities, including the World Health Organization and relevant embassies, and is considering sailing to the Canary Islands, over 1,600km away.

Oceanwide Expeditions added that it was in close contact with the families of the 61 crew members and 88 passengers aboard.

There are currently no vaccines or specific medications to combat the various hantaviruses, meaning that treatment consists solely of attempting to relieve the symptoms after they appear.

The World Health Organization's Europe director, Hans Kluge, has stated that the virus "is not easily transmitted between people".

"The risk to the wider public remains low. There is no need for panic or travel restrictions," he said.

* This article was originally published on Evoke.ie.