Dysentery is an infection of the intestines that causes diarrhoea containing blood or mucus.
Other symptoms of dysentery can include:
painful stomach cramps
nausea or vomiting
a high temperature (fever) of 38C (100.4F) or above, or 37.5C (99.5F) or above in children under five
In the UK, most people with dysentery only experience mild symptoms. It's not always necessary to see a GP, as it tends to clear up within a week or so.
See your GP if your symptoms are severe or don't start to improve after a few days. Tell them if you have recently been abroad.
Treatment isn't normally needed, as it usually clears up on its own. However, it's important to make sure you drink plenty of fluids and use oral rehydration solutions (ORS) if necessary, to avoid dehydration. See treating diarrhoea for more information on this.
Over-the-counter painkillers such as paracetamol can help to relieve pain and a fever. It's best to avoid antidiarrhoeal medications such as loperamide, as they can make things worse.
You should stay at home until at least 48 hours after the last episode of diarrhoea, to reduce the risk of passing the infection on to others.
If your symptoms are severe or persistent, your GP may prescribe a short course of antibiotics. In severe cases, you may need to be treated in hospital for a few days.
What causes dysentery?
There are two main types of dysentery:
bacillary dysentery or shigellosis – caused by shigella bacteria; this is the most common type of dysentery in the UK
amoebic dysentery or amoebiasis – caused by an amoeba (single-celled parasite) called Entamoeba histolytica, that's found mainly in tropical areas; this type of dysentery is usually picked up abroad
Both types of dysentery are highly infectious and can be passed on if the poo of an infected person gets into another person's mouth. This can happen if someone with the infection doesn't wash their hands after going to the toilet and then touches food, surfaces, or another person.
In the UK, the infection usually affects groups of people in close contact, such as families, schools and nurseries.
There is also a chance of picking up the infection through anal or anal-oral sex ("rimming"), particularly in men who have sex with other men.
In developing countries with poor sanitation, infected poo may contaminate the water supply or food (particularly cold, uncooked food).
You can reduce your risk of getting dysentery with good hygiene. You should:
wash your hands with soap and warm water after using the toilet, and regularly throughout the day
wash your hands before handling, eating or cooking food
avoid sharing towels
wash the laundry of an infected person on the hottest setting possible
If you're travelling to a country where there is a high risk of getting dysentery, the advice below can help to prevent infection.
Don't drink the local water unless you're sure that it's sterile (clean) – safe alternatives are bottled water or drinks in sealed cans or bottles.
If the water is not sterile, boil it for several minutes or use chemical disinfectant or a reliable filter.
Don't clean your teeth with tap water.
Don't have ice in your drinks, because it may be made from unclean water.
Avoid fresh fruit or vegetables that can't be peeled before eating.
Avoid food and drink sold by street vendors (except drinks from properly sealed cans or bottles).