An Australian who was onboard a luxury cruise ship during an outbreak of the deadly rat-borne hantavirus has since returned home. 

At least three Australians are among 149 passengers who remain stranded onboard the MV Hondius, which remains moored off the coast of Cape Verde, West Africa.

The ship, which had been on a voyage from Argentina to Antarctica, requested help from authorities on Sunday following the death of a third passenger – a German national.

An elderly Dutch couple died last month.

The incubation period for symptoms of the virus is up to eight weeks, sparking fears the virus may have spread to Australia. 

It has now been revealed that an Australian passenger was among 23 who disembarked the ship at St Helena -a remote island in the South Atlantic Ocean on April 21 – 10 days after the first death onboard was recorded.

One of those who disembarked has since tested positive to the virus and is recovering in hospital in Switzerland, according to a Spanish passenger still stranded onboard. 

‘Until three days ago, no one had contacted them,’ the passenger told Spanish newspaper El Pais.

‘The Australian went back to Australia, the one from Taiwan to Taiwan, the Americans to all corners of North America. The Englishman to England, the Dutch to their homes.’ 

The passenger also claimed that the World Health Organisation did not start contacting disembarked passengers until earlier this week – a month after the first infected passenger fell ill.

It has since emerged that the virus may have been brought onto the ship by a birdwatching couple, according to Argentinian officials.

Investigators said a Dutch couple, who later boarded the MV Hondius, visited a landfill site to snap birds in the city of Ushuaia, and may have been exposed to rodents carrying the lethal infection.

It has not yet been confirmed whether it was the same Dutch couple who later died from the virus. 

All passengers who remain onboard have been instructed to remain inside their cabins to prevent any potential spread of the virus. The number of cases currently stands at eight.

It is not known when the cruise ship will be able to dock.

‘Oceanwide Expeditions remains in close and continual discussion with relevant authorities regarding our exact point of arrival, quarantine and screening procedures for all guests, and a precise timeline,’ the operator said in a statement.

‘We are unable to confirm the details of onward travel for guests at this stage.’

Hantavirus is transmitted to humans through infected wild rodents, such as mice or rats, which shed the virus in their saliva, urine and droppings.

Infection can occur through a rodent bite, direct contact with rodents or their droppings, or by inhaling contaminated dust.

Initial symptoms, which can appear up to eight weeks after exposure include fever, fatigue, and muscle ache.

It can cause severe respiratory illness and there is no cure.

The virus has a mortality rate of up to 40 per cent.

The first passenger who passed away onboard was a 70-year-old Dutch man on April 11.

The cause of death could not be determined on board, with his body disembarked from the ship at St Helena 13 days later. 

His 69-year-old wife accompanied the repatriation but become unwell during the return journey and had later died. A variant of hantavirus was identified in the woman.

A German passenger died onboard the ship on May 2. Their cause of death has not yet been formally established.