Virus World

“Incidence of mild gastrointestinal illness among guests onboard Nieuw Amsterdam are suspected to be the common but highly contagious Norovirus, which is typically transmitted through close contact with unwell people and includes touching shared items,” Holland America Line said in an emailed statement. “The cases have been mostly mild and quickly resolving.” The CDC says crew on the ship, which can carry more than 2,100 passengers, are increasing cleaning and disinfection procedures and collecting stool specimens to send to a lab to confirm the cause. Once it arrives in Vancouver, the vessel will go through extra disinfection, leading to a slightly delayed departure time. According to a CDC norovirus tracking network that uses information from 14 states, there were 735 outbreaks reported from August through April 23. There were 907 during the same period of the 2021-2022 norovirus season. Norovirus causes 19 to 21 million illnesses on average every year in the U.S., the agency says. Outbreaks of gastrointestinal illness plummeted during the pandemic, which shut down the cruise industry for more than a year and forced a slow return with multiple health precautions in place. There were no reported cases in 2020, followed by one in 2021 and four last year.

William Schaffner, a professor of infectious diseases at the Vanderbilt University School of Medicine in Nashville, told The Washington Post last year that the lower number of cruises, reduced concentration of passengers and coronavirus precautions were all factors in the drop in cases. “The more rigorous we are with all of these hygienic measures, there’s spillover to other infectious agents,” he said. Health authorities say cruise passengers should wash their hands often and leave the area if they see someone get sick. If people are sick before a cruise, they should ask about alternative options and ask a doctor if it’s safe to sail. The Cruise Lines International Association says incidents of gastrointestinal illness are “quite rare” on ships, pointing to the millions who get sick every year on land. The group said in a statement that crew members clean and sanitize using practices developed with public health authorities, including the CDC. “All of the efforts made by cruise ship crews cannot replace the responsibility that rests with each and every individual,” the association said. “Passengers and crew alike must also be committed to keeping themselves, their family and their fellow travelers healthy.” Through its Vessel Sanitation Program, the CDC inspects cruise ships, monitors illness, trains crew and provides public health information. The agency releases information on outbreaks when 3 percent or more of passengers or crew report symptoms to medical staff on board. “Norovirus can be especially challenging to control on cruise ships because of the close living quarters, shared dining areas, and rapid turnover of passengers,” the CDC says. “When the ship docks, norovirus can be brought on board in contaminated food or water or by passengers who were infected while ashore.” Because norovirus can linger on surfaces and resists many common disinfectants, it can result in outbreaks on back-to-back cruises. Still, the agency says norovirus on cruise ships only account for 1 percent of all reported outbreaks of the illness and notes that “acute gastrointestinal illness is relatively infrequent” on ships. “Health officials track illness on cruise ships,” the CDC says. “So outbreaks are found and reported more quickly on a cruise ship than on land.”