Cruise ships are floating petri dishes for gastro bugs
Cruises in particular are notorious for gastro outbreaks. In one study that looked at nearly 2,000 cruise ships docking Sydney, 5% reported a gastro-related outbreak.
There’s no reason to panic if you’re going on a cruise. You can take some precautions to ensure a healthy, happy holiday.
What is gastro?
In Australia, viruses are the main cause of acute gastroenteritis. The main cause of gastroenteritis in Australia is Norovirus, which causes an estimated 2,2 million cases each year.
The most common way that Norovirus spreads from one person to another is via the oral-faecal route. This means that virus particles in the stool of a person are swallowed and transmitted by the next person.
In feces and vomiting, a large number of virus particles are shed. However, a person needs only to ingest very few virus particles to become infected.
Read more: Health Check: how long are you contagious with gastro?
Norovirus is hardy and can resist acid conditions (like those in the gut) and moderate temperatures (at which we wash clothes or reheat food, for example). Further, many chemicals used in cleaning products and hand sanitisers don’t effectively remove norovirus.
Diarrhoea, and sometimes vomiting are the main symptoms of gastro due to norovirus. The symptoms usually last only a few days ( 2 to 3 days) and stop by themselves. Dehydration is the main concern, especially for children and elderly people.
The most common cause of gastroenteritis in Australia is norovirus. Shutterstock.com
Norovirus in cruise ships
In general, a ship will declare “gastro symptoms” when 2-3% of the passengers or crew members are sick. On a cruise ship with 2,000 passengers, it would take 40-60 sick people to declare an outbreak.
A Australian study revealed that 5% of the cruise ships arriving in Sydney from 2007 to 2016 reported gastro-intestinal outbreaks (98 of 1967). Ninety-three percent of the outbreaks that had a cause were caused by norovirus.
There are reports in the media from time to time about significant outbreaks, such as when the Sea Princess reported 200 cases in 2018 of gastro due to norovirus.
Read more: Viruses aren’t all nasty – some can actually protect our health
How does it spread?
Norovirus can infect you before the symptoms even appear, and after they have resolved. A person could unknowingly carry norovirus on a cruise.
Norovirus on cruise ships is spread mainly from to. It is not surprising that many cruise activities involve passengers mixing in a relatively closed environment.
A handshake may be a common greeting, but it is not a sanitary one. A study found that a “fist bump” could be used on cruise ships, and a modified version called the “cruise tap” (where two knuckles were touched) would be even more effective.
You’ll be asked to remain in your cabin if you catch gastro while on a cruise. This is to prevent it from spreading to other passengers. Shutterstock.com
Norovirus can also spread by touching contaminated surface. Norovirus can cause a person to not wash their hands after using the toilet. This leaves many norovirus particles visible on their hands.
This person leaves norovirus particles behind when they touch surfaces (for instance, handrails, buttons on the lift or utensils in the buffet). The particles can be transferred to other people’s hands by touching these surfaces. If they then put their hands on their mouths, they could get the virus.
Read more: Health Check: should I use antibacterial hand sanitisers?
It’s rare to inhale norovirus particles from the air, but it can occur, usually if someone with the virus vomits nearby.
Cruise ships adhere to strict food handling procedures in order to prevent illnesses like norovirus. Although this does not mean that it is unheard of.
