The U.S. Centers for Disease Control and Prevention (CDC) confirmed that dozens of people on a Holland America cruise liner fell ill in a norovirus outbreak that started earlier this month.

In a statement on Dec. 12, the agency said that 74 passengers out of about 1,923 guests reported being sick on the cruise operator’s Zuiderdam ship starting Dec. 4. Four crew members out of 757 were also sickened, the agency said.

Their primary symptoms were vomiting and diarrhea, according to the CDC, which listed the “causative agent” as norovirus, an illness also known as the Norwalk virus that health officials say is highly contagious.

According to the CruiseMapper website, the Zuiderdam, is currently on a 17-day cruise through the Caribbean, having departed from Fort Lauderdale, Florida, and is scheduled to return on Dec. 21. It’s currently docked in the Dominican Republic.

Holland America told the CDC that it has taken corrective actions in response to the outbreak such as “increased cleaning and disinfection procedures according to their outbreak prevention and response plan.”

The operator has “collected stool specimens from gastrointestinal illness cases for testing” and has “isolated ill passengers and crew,” the agency said.

The CDC also is sending a field response team to investigate the incident.

The Epoch Times contacted Holland America for comment, and a company spokesperson told several news outlets that it “enhanced sanitation protocols in conjunction” alongside the CDC to mitigate transmission of the virus.

“As a further precaution, upon arrival in Fort Lauderdale Saturday, the ship will undergo additional and comprehensive sanitization before embarking on its next voyage,“ the spokesperson said. ”Guests have been notified of updated boarding times to allow for the additional disinfection.”

So far in 2024, the CDC has recorded 12 outbreaks of gastrointestinal illnesses on cruises, most of which were caused by norovirus. One outbreak was caused by salmonella, another by E. coli, and one was listed as “unknown,” according to the agency.

In 2023, the CDC reported 14 outbreaks on cruise ships, and norovirus was listed as the causative agent in all but one of the incidents.

“Norovirus is often a cause of GI outbreaks on cruise ships, but we don’t always know the cause of the outbreak when we begin an investigation,” the CDC says. “Finding the agent that caused an outbreak (causative agent) can take time. When an outbreak occurs, people whose symptoms met the case definition are asked to provide stool or vomitus samples.”

Cruise ships are required to report cases where individuals report diarrhea or vomiting, along with other symptoms, to the CDC, the agency said.

Norovirus Outbreaks

In a normal year, according to the CDC, norovirus causes between 19 million and 21 million cases of vomiting and diarrhea, 109,000 hospitalizations, and 900 deaths across the United States. The virus also is associated with about 495,000 emergency department visits, mostly in younger children, the CDC says. Most outbreaks occur between November and April.

If there is a new strain of the virus, there can be upward of 50 percent more norovirus illness. the agency said. Norovirus outbreaks often occur in health care facilities, long-term care facilities, restaurants, childcare centers, schools, and cruise ships.

Making note of the association between norovirus outbreaks and cruise ships, the CDC says that more than 90 percent of “outbreaks of diarrheal disease on cruise ships” are caused by the virus.

“These outbreaks often get media attention, which is why some people call norovirus the ‘cruise ship virus,'” a CDC website page states.

But norovirus outbreaks on cruise ships amount to “only a small percentage (1 percent) of all reported norovirus outbreaks,” the agency says. “Norovirus can be especially challenging to control on cruise ships because of the close living quarters, shared dining areas, and rapid turnover of passengers.”