By Hannah Sampson
As cruise passengers return to the seas in force following a pandemic lull, an unwelcome side effect is also back: outbreaks of gastrointestinal illness.
According to the Centers for Disease Control and Prevention, so far this year, there have been 11 outbreaks of vomiting and diarrhoea that reach the threshold for public notification on cruise ships visiting US ports.
The mid-May tally has already exceeded the total number of outbreaks reported in 2019 and tied the yearly number for both 2017 and 2018.
Norovirus has been identified as the culprit in four of the 2023 cases; the others are all classified as unknown.
The Cruise Lines International Association, a trade group, and the CDC did not immediately provide responses to questions about the increase in cases this year.
In the latest outbreak aboard Holland America Line's Nieuw Amsterdam, 160 passengers and 26 crew have reported being ill.
That represents a little more than eight percent of guests and three percent of workers. The ship is on a 14-day Alaska cruise that returns to Vancouver on Sunday.
‘’Incidence of mild gastrointestinal illness among guests on-board 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 the 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.
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.
‘’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 accounts for 1% 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.’’
Read the latest issue of IOL Travel digital magazine here.