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Norovirus and Shigellosis – what causes these illnesses?

cruise ships have been linked with Norovirus

There have been more than six outbreaks of viruses, especially Norovirus, on cruise ships so far this year.  This might seem a large number, but in actual fact the likelihood of contracting Norovirus on a cruise ship is just one-eighteenth of a percent. You are far more likely to contract Norovirus on dry land.

Nevertheless, cruise liner operators are particularly scrupulous about hygiene.  Ascend or descend any of the stairways and you will find staff cleaning the handrails.  Walk into a restaurant or buffet area and there are hand sanitation stations.  On some ships, they even have a member of staff standing at the entrance with spray gun dispensing sanitiser directly into guests’ hands.  It’s a similar situation before you board the vessel.

To illustrate the point; I was having dinner on a cruise ship recently. The lady on the table adjacent was about to order, but just before she did, she sneezed.  The waiter immediately whisked the menu out of her hands, put it in a cupboard, sanitised his hands and handed her a new menu. The woman was astonished at his reaction, but he was, of course, quite correct to do so.

Norovirus spreads rapidly

Why are they so hot on hygiene? The answer lies in the fact that there are thousands of passengers and staff in close proximity.  An illness such as Norovirus, which causes sickness and diarrhoea, can therefore spread rapidly.

toilet rolls for diarrhoeaNorovirus can be transmitted directly or indirectly.  In other words, person-to-person, or through contaminated water or food.  So, for example, if you touch a door handle, surface or utensil (or menu for that matter) of someone who contracted the virus, you can become infected yourself.  It can also spread through eating contaminated food prepared by infected food handlers.  Norovirus can become airborne via toilet flushing or you can catch it by being nearby somebody vomiting. It takes fewer than 20 virus particles to cause an infection.  Scary stuff!

 

Which foods are best to avoid?

shellfish and saladFood-wise the most likely candidates to be implicated in a Norovirus outbreak are salad ingredients and shellfish.  If shellfish have not been heated above 75?C, they pose a serious risk.  If infected water is used to wash fruit and vegetables, or to make ice, that will also cause the virus to spread.  But it’s not only potable water that can become contaminated.  Waterborne outbreaks of Norovirus have also been sourced in swimming pools and recreational lakes.

Norovirus can survive for long periods outside the human body. Contaminated fabrics can hold the virus for up to 12 days.  It can live for weeks on hard surfaces and potentially for years in contaminated still water.  So, food safety and general hygiene are obviously of paramount importance.

How can we protect ourselves against contracting the virus?

One of the most effective things you can do is wash your hands properly with soap and water. This is actually more effective than using an alcohol rub. You can also ensure all surfaces are sanitised with a solution of bleach and water or other disinfectants. You might also want to side-step the salad and shellfish to be absolutely sure.

What is Shigellosis?

Shigellosis, a highly contagious diarrhoea caused by Shigella bacteria, is often confused with Norovirus. It also has a similar make-up to E.coli bacteria.

Shigella can spread in schoolsShigella bacteria is most commonly seen in schools and child care environments.  It can spread quickly and is generally spread through people not washing their hands after using the toilet or changing a nappy.  They then touch other surfaces or food. All someone has to do is touch the same surface/utensils and then touch their mouth and they can fall victim to Shigellosis.  It can even be spread via sex with an infected person.

The bacteria can affect any food which has been washed in contaminated water.  That’s why it is often referred to as ‘travellers’ diarrhoea’, since it is contracted through contaminated food and water in developing countries.

Did E-Coli kill holidaying couple?

Post-mortem tests carried out on the bodies of a couple from Burnley who died suddenly whilst  holidaying in Hurghada, Egypt, showed high levels of E.Coli  The E.Coli bacteria causes very similar symptoms and is transmitted in similar ways to the Shigellosis virus.

E. Coli is present in the guts of humans and animals and can be transferred through not washing hands after using the toilet, eating undercooked meat, drinking unpasteurised milk and fruit juices or drinking contaminated water etc. You are also more susceptible to illness from E. Coli and other bacteria if you have a weakened immune system; are elderly or very young; or are taking medication to decrease stomach acid levels.

Most strains of E. Coli are harmless and may cause a little discomfort. However severe strains can cause fever as well as stomach cramps, diarrhoea and nausea and can lead to a condition called Haemolytic Uremic Syndrome (HUS). In HUS the red blood cells are damaged and this can lead to kidney failure. This can occur in 5 -10% of people infected with E. Coli.

Learn about food poisoning bacteria and their control

You can find out all about cross contamination and the various bacteria which cause food poisoning on our Food safety courses.  We offer all levels from basic Level 2 Food Safety & Hygiene, Level 3 Food Safety & Hygiene for supervisors to advanced Level 4 Food Safety and Hygiene. All are available as open courses at our training facility.  Alternatively, if you have 5 or more people to train, a cost-effective option is the same course run in-house at your own premises.

 

Click here for more information.

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