Singapore has isolated and is testing two residents who were aboard a cruise ship linked to a deadly hantavirus outbreak, the Communicable Diseases Agency (CDA) said on Thursday.Countries around the world are tracing passengers from the virus-hit ship to prevent further spread of hantavirus. Three people — a Dutch couple and a German national — have died in the outbreak on the MV Hondius, while eight others are believed to have contracted the virus.Hantavirus is usually spread by rodents but, in rare cases, can be transmitted from person to person. The two Singapore residents, aged 67 and 65, have been isolated at the National Centre for Infectious Diseases. They were onboard the MV Hondius when it departed from the Argentine port of Ushuaia on April 1, the CDA said in a statement.“One has a runny nose but is otherwise well, while the other has no symptoms. The risk to the general public in Singapore remains low,” the CDA said.If they test negative for hantavirus, the men will be quarantined for 30 days from the date of last exposure. If they test positive, they will remain hospitalised for monitoring and treatment.Both men had disembarked from the ship and were also on the same flight as a confirmed hantavirus case travelling from St Helena to Johannesburg on April 25. The confirmed case did not travel to Singapore and has since died in South Africa, the agency added.