(RxWiki News) Nothing can ruin a vacation like a bout of food poisoning. But new evidence suggests the risk may be lower than ever — at least on US cruise ships.
Although outbreaks of foodborne illness on cruise ships tend to dominate the news, the actual number of outbreaks that occur is relatively small, reported the Centers for Disease Control and Prevention (CDC) this week.
In fact, cases of acute gastroenteritis — the illness responsible for diarrhea, nausea and vomiting, among other symptoms — have dropped significantly on cruise ships in recent years.
Of the more than 29,000 voyages that took place between 2008 and 2014, only 133 outbreaks of acute gastroenteritis were reported. That's less than 1 percent of the time. And only a small fraction (0.18 percent) of the nearly 74 million passengers who cruised during that time reported symptoms of acute gastroenteritis. About 0.15 percent of the 28 million crew members reported the same.
In spite of these findings, Walker Winn, PharmD, told RxWiki News that cruise ship passengers should be wary of foodborne illness.
"In environments where people are living in close quarters for long or short periods of time, including cruise ships, viruses can spread quickly and easily," Dr. Winn said. "Certain viruses can even remain infectious outside the body for limited periods of time."
Still, these numbers suggest that the cruise industry has been doing a better job in recent years of preventing and controlling outbreaks. In 2001, both the CDC's Vessel Sanitation Program and the cruise industry expanded their definitions of diarrheal illness to include acute gastroenteritis.
About 92 percent of outbreaks that did occur were caused by norovirus, the leading cause of illness from contaminated food in the US, according to the CDC. Others were caused by bacteria like E. coli or parasites.
Norovirus is the collective name for a group of viruses that cause inflammation of the stomach and large intestine lining (gastroenteritis). These viruses are found in the stool or vomit of infected people.
Food contamination can occur at the source, such as seafood harvested from contaminated waters, or by an infected food handler through poor hygiene. Norovirus can also spread quickly from person to person through shared food or utensils, by shaking hands or through other close contact.
The CDC estimates that each year norovirus causes as many as 21 million illnesses, 71,000 hospitalizations and 800 deaths.
To further reduce the rates of acute gastroenteritis on cruise ships, the CDC recommends passengers practice good hygiene, making sure to wash hands especially after using the restroom and before eating.
When washing hands, Dr. Winn said that soap and water is best.
"Hand sanitizer is not always effective and soap allows for a more thorough removal of certain infectious agents, which may be relatively unaffected by alcohol-based products," Dr. Winn said. "Alcohol-based hand sanitizers can be used in addition to soap or if soap is not available."
Dr. Winn also recommends passengers wash hands after coming in contact with commonly-touched surfaces like doorknobs and handrails, use their own cabin's restroom instead of common facilities when possible, and avoid touching food with their hands.
According to the CDC, passengers experiencing diarrhea or vomiting should promptly report their illnesses to the ship medical center for assessment, treatment and monitoring.
This report was published Jan. 15 on the CDC's website in the Morbidity and Mortality Weekly Report.
No funding sources or conflicts of interest were disclosed.