Hundreds of passengers and crew members have fallen ill aboard the Princess Cruises cruise ship, but the cause of their suffering remains a mystery, reports CBS News.

A total of 284 of the 2,881 passengers aboard the massive Ruby Princess cruise ship reported feeling ill during the trip between February 26 and March 5, researchers from the United States’ Centers for Disease Control and Prevention (CDC) said.

In addition, 34 of the 1,159 crew members reported illness. The indicated symptoms were vomiting and diarrhea.

Epidemiologists and environmental agents from the CDC’s Ship Sanitation Program arrived as soon as the ship docked in Galveston, Texas, on March 5. What caused the diseases has not yet been established.

The crew on the ship were cleaning and using disinfection procedures more often when the outbreak started on board, the CDC said. They also collected stool samples for CDC analysis.

Employees advised sick passengers to isolate themselves in their rooms, a Princess Cruises spokesman said.

Norovers, the prime suspect

The company believes the illness is likely caused by norovirus, a highly contagious virus that causes vomiting and diarrhea. Norovirus, sometimes called the “cruise ship virus,” causes more than 90 percent of diarrheal illness outbreaks on cruise ships, according to the CDC.

Meanwhile, Ruby Princess has embarked on a new journey, the company said. The latest group of passengers, currently on a seven-day Caribbean cruise, have been told of an increased number of illnesses on a previous flight.

The Ruby Princess has previously made headlines as the site of several COVID-19 outbreaks, including during a 2020 cruise at the start of the coronavirus pandemic when it docked in Australia with hundreds of positive cases on board.

In recent years, the CDC has tracked outbreaks of COVID-19 on cruise ships, but the case tracking program ended in July 2022. (news.ro)