At least 340 sickened on cruise ship in Brazil

Hundreds of passengers on a Swiss-owned cruise ship were stricken with severe vomiting and diarrhea caused by a mysterious ailment, Brazilian health officials said Thursday.

At least 340 victims have been sickened on the MSC Sinfonia, now docked in Salvador, Bahia, according to a spokeswoman for the National Agency for Sanitary Vigilance. She spoke on condition of anonymity, in line with department policy.

The illness didn't appear to be life-threatening and most passengers were recovering Thursday.

The agency said later in a statement that an inspection found problems with the amount of chlorine in the ship's drinking water and with the storage of some perishable food items, notably mayonnaise.

But officials said they would not know what caused the illness until they wrap up their investigation.

The health agency said the outbreak was under control, and the victims were being interviewed and treated on board the ship. Most fell ill on Monday and Tuesday.

The vessel is owned by MSC Cruises, a division of the Geneva-based Mediterranean Shipping Co. An MSC Cruises spokeswoman in Sao Paulo declined to comment.

The Sinfonia left Rio de Janeiro on Friday with 2,000 passengers, mostly Brazilians.

Health officials gave approval for the ship to return to Rio, but ordered cruise officials to notify authorities immediately should new cases of illness break out.