The World Health Organization said Thursday that more hantavirus cases may emerge from a cruise ship outbreak that has killed three passengers, but officials expect it to remain limited if proper health measures are taken.

Another infected passenger from the MV Hondius arrived in Europe as the ship continued toward Spain’s Canary Islands, while authorities traced contacts linked to the outbreak of the rare Andes strain of the virus.

The outbreak has caused international concern after three deaths, though officials stressed the virus is less contagious than COVID-19 and not expected to spread widely.

A Dutch couple who boarded the ship in Ushuaia, Argentina, on April 1 were the first fatalities.

Argentine health authorities said the source of the outbreak remains unknown.

WHO Director-General Tedros Adhanom Ghebreyesus said five confirmed and three suspected cases, including the deaths, had been reported.

He warned that additional cases were possible due to the virus’s incubation period of up to six weeks.

The Leiden University Medical Centre later confirmed another positive case.

WHO emergency response director Abdi Rahman Mahamud said the outbreak was likely to remain “limited” with coordinated public health action.

Cases have been reported or are being monitored in Britain, Germany, the Netherlands, Switzerland and South Africa.

Hantavirus, spread mainly by rodents, can cause severe respiratory and cardiac illness and has no vaccine or cure.

Authorities believe one passenger was infected before boarding in Argentina and transmitted the virus onboard.

Rodent testing is planned in Ushuaia, where the voyage began.

Several passengers have been evacuated or tested positive across Europe and Africa, while contact tracing continues for a flight from Saint Helena to Johannesburg.

A German passenger died May 2, and her body remains aboard the ship.