What is it?

Dysentery is an infection of the digestive system caused, usually, by a bacterium called Shigella. It is highly infectious because the infective dose (the number of bacteria that are required to produce illness) is very low. Anyone can become infected although it is most common in children aged under 10 years. The incubation period can be anywhere between 10 hours to 7 days, usually 2 to 3 days. The majority of cases clear up after 2 to 3 days but some patients may be ill for 2 to 3 weeks. The onset is usually abrupt with fever followed by vomiting, abdominal pain and profuse diarrhoea.

How do you catch it?

The source of dysentery bacteria is the faeces (stools) of infected persons, particularly those persons who still have diarrhoea.

The infection is mainly spread by the 'faecal-oral' route from person to person, in fact this disease is only a disease of man, involving hand to mouth transfer via materials and surfaces contaminated by an infected person, e.g. the person who used the toilet before you may have left bacteria on the seat, handle or door.

Some more severe forms may be caught abroad, especially in tropical countries.

How can you avoid it?

By scrupulous attention to hygiene. Always wash and dry your hands thoroughly after using the toilet and teach your children the importance of doing the same.

What is the treatment?

If you have diarrhoea then drink plenty of fluids. Antibiotics are not usually helpful in dysentery, although if you are extremely poorly your doctor may give them.

What can you do to prevent further spread?

Pay particular attention to personal hygiene - hands should be thoroughly washed (using hot water, soap and a nail brush) after using the toilet and immediately before any handling, preparing or serving of food. Towels should not be shared. Children should be supervised in their hand washing after using the toilet and before eating food. Particular care should also be taken if you have to attend to elderly relatives suffering from diarrhoea associated with a Shigella infection.

Soiled clothing and bed linen should be washed in a domestic washing machine with a 'hot cycle'. As much faecal matter as possible should be flushed down the toilet. Soaking in a household disinfectant may also be used, before washing, to reduce contamination.

Disposable plastic or rubber gloves should be worn and hands thoroughly washed afterwards.

Clean toilet seats, flush handles, door handles and taps frequently with hot soapy water. You do not need to use disinfectants, but if you want to then follow the manufacturer's instructions carefully, and keep them away from children. Shigella bacteria are quite hardy and can remain on such objects for some time, capable of being picked up on the hands of any person and then transferred to their mouth.

When can you return to work/school?

You should stay away from work or school until you have been free from diarrhoea and vomiting for at least 48 hours. The Environmental Health Department may tell you to stay off longer or may ask for further faeces specimens, especially if you work in food preparation, child care etc. You must follow their advice.