The battle against stomach bugs
It's been an annus horribilus for the cruise industry.
Highly publicised mechanical problems, an onboard fire, cancellations, deaths at sea and outbreaks of sickness have followed the Costa Concordia disaster to seriously mar the reputation of the otherwise booming industry.
Images of passengers living in filthy conditions and begging to be taken off a ship drifting at sea are not exactly the makings of travel wish-lists.
Nor are reports of passengers lying in corridors or being carried off ships because they're too sick to do anything else; it's a public relations nightmare.
Now we have claims of ship spas infected with flesh-eating bacteria. A class action lawsuit is being fought vigorously but that is a hard thing to forget once you've heard it.
Many of the events of the past year have been one-offs but gastro outbreaks are a significant threat to the image of cruising.
When you're handed a fact sheet on diarrhoea as you board, that makes you think twice. Even if you avoid getting sick, you might not be lining up to book another cruise in a hurry.
It's becoming an expensive issue for cruise lines, which are being hit by claims for refunds or compensation from passengers who have spent their holiday with their head in the toilet.
And with no real means of prevention, other than good hygiene, it is a problem that's not going away.
The national medical adviser for The Travel Doctor-TMVC, Tony Gherardin, says outbreaks of vomiting and diarrhoea on ships are almost always caused by noroviruses, which are highly infectious.
"Noroviruses have probably been around forever for they seem to have emerged in recent years as a cause of major outbreaks," says Gherardin.
"Unfortunately, cruise ships have been victims because you only need one passenger or one crew member to have been infected onshore and it very rapidly spreads around the ship.
"The ship itself gets infected, if you like, because the kitchens and the water supply and other facilities get contaminated and it's very difficult to get rid of.
"They can be like wildfire, these noroviruses, and it trashes the reputation of the cruise line."
Gherardin says the only way to put a stop to a norovirus outbreak is to dock the ship and sterilise it from top to bottom.
"It's a big issue and it's very expensive for them," he says. "They take it very seriously and try to minimise the exposure."
The important thing to know about noroviruses - and apologies if you're eating - is that they are spread by oral faecal contamination; in other words, when traces of poo find their way into mouths via hands or food.
The only means of prevention, according to Gherardin, is regular, quality hand washing or regular use of hand-sanitising gels, particularly before eating or drinking.
There is no advantage to either method, he believes, as long as it is done properly - "not just a cursory dampening of the hands".
Ships often make hand gel available at the entrance to restaurants and other facilities and may even have staff on hand to enforce its use.
If you do get infected with a norovirus, the symptoms are "fairly obvious" and come on rapidly, with diarrhoea accompanied by vomiting.
"Often people are confined to their bunk for two to three days and it can be devastating for their trip," Gherardin says.
"For the very old and very young it can be quite [medically] serious."
Passengers who suffer from a gastro outbreak are usually asked to remain in their cabin, or in a nominated area of the ship, with medical attention and room service brought to the cabin.
Refunds or partial refunds may be offered by the cruise line or demanded by the passenger, depending on the circumstances.
Gherardin says there is no specific treatment for norovirus, only fluid replacement and anti-nausea drugs to help manage the symptoms and avoid dehydration.
Travellers can buy gastro kits containing prescription medications such as anti-nausea drugs at travel medicine centres, or anti-diarrhoea tablets are available without prescription through chemists.
Gherardin says being in good general health may help but noroviruses don't generally discriminate.
"If you get a dose of norovirus, it's probably not going to make a lot of difference," he says.
You could look on the positive side: it might be one holiday where you lose weight.
Sydney Morning Herald