BORDEAUX, France (AFP) — French authorities on Wednesday allowed asymptomatic passengers to leave a British cruise ship, saying a gastrointestinal virus was behind an outbreak of sickness that came after an elderly man died of a heart attack.

Earlier, authorities had ordered a lockdown for the more than 1,700 passengers and crew on the vessel, but insisted there was no connection with the hantavirus outbreak suspected of killing three people on the Dutch-flagged MV Hondius cruise ship, which has sparked international alarm.

Testing confirmed the outbreak on the Ambition, a cruise ship anchored in the port of Bordeaux in western France, was “a gastro-intestinal infection of viral origin,” the local government and regional health agency said in a statement.

They said there were no severe cases, and that asymptomatic individuals were now free to disembark, but that those infected were required to remain in isolation on board.

News that a 92-year-old British passenger had died on the ship as dozens of others suffered upset stomachs initially caused concern.

But health authorities said the man had suffered a heart attack and that his death appeared unrelated to the illnesses.

“At this stage, no link has been established with the gastroenteritis episode,” they said.

Port authorities said his body remained on board, “in accordance with international conventions.”

Authorities said that since Monday, 80 people on the ship had suffered from “symptoms consistent with an acute digestive infection.”

They said the lockdown order had been issued as an “abundance of caution” and to “avoid psychosis,” given international worry over the hantavirus outbreak on the Hondius, which set sail from Argentina and is now heading back to the Netherlands after being evacuated.