Shigella are a group of germs (bacteria) that can cause gastroenteritis with dysentery. Gastroenteritis is an infection of the bowels (intestines). Diarrhoea is one of the symptoms of gastroenteritis. If the diarrhoea contains blood and mucus, this is known as dysentery. If someone is infected with shigella, the bacteria can pass out in their stools (faeces). Infection with shigella may be caught by drinking water contaminated with infected faeces, eating food prepared using contaminated water or by close contact with someone who has the infection. Infection may occur in people who have travelled to countries with poor sanitation but infection can also be caught in the UK. Treatment is with antibiotic medicines and fluids to prevent or treat lack of fluid in the body (dehydration).
Gastroenteritis is an infection of the bowels (intestines). How bad it is (its severity) can range from a mild tummy (abdominal) upset for a day or two with some mild diarrhoea, to severe diarrhoea and being sick (vomiting) for several days or longer. Many germs (viruses, bacteria and other microbes) can cause gastroenteritis.
Diarrhoea is defined as 'loose or watery stools (faeces), usually at least three times in 24 hours'. Diarrhoea is one of the symptoms of gastroenteritis. If the diarrhoea contains blood and mucus, this is known as dysentery.
Most cases of gastroenteritis do not lead to bloody diarrhoea and so are not dysentery. However, there are a number of microbes that can cause dysentery. These include campylobacter, Entamoeba histolytica, Escherichia coli (E. coli), salmonella and shigella.
See separate leaflets called Campylobacter, Amoebiasis, E. coli and VTEC O157 and Salmonella for further details. The rest of this leaflet is just about dysentery caused by shigella infection.
Shigella are a group of germs (bacteria) that can cause gastroenteritis with dysentery. Gastroenteritis is an infection of the bowels (intestines). Dysentery caused by shigella is also known as bacillary dysentery. There are four different species of shigella: Shigella dysenteriae, Shigella flexneri, Shigella boydii and Shigella sonnei.
If someone is infected with shigella, the bacteria can pass out in their stools (faeces). Infection may be passed on to others if drinking water is contaminated with infected faeces or if food is washed in contaminated water and then eaten. Because shigella infection can be passed on by drinking contaminated water or eating contaminated food, shigella can be a cause of food poisoning.
If you have shigella, you may also spread the infection to your close contacts if you do not follow strict hygiene measures to prevent the spread of infection to others (see below).
Anyone can get shigella infection. However, infection is more common in young children. Commonly, people with shigella infection have travelled to a country where sanitation and hygiene is poor. However, infection can also be caught in the UK. Shigella sonnei is the most common species found in the UK. It tends to cause a mild illness. One group of people recently found to be at risk of shigella are men who have sex with men when contact with the back passage (anus) is involved.
Some people with shigella infection actually have no symptoms. However, the germs (bacteria) will still be present in their stools (faeces) and they can still pass on the infection to other people.
But most people with shigella develop symptoms. Symptoms tend to come on within one to seven days of contact with the bacteria (eg, drinking contaminated water, eating contaminated food). This time period before symptoms appear is known as the 'incubation period'. The usual symptoms are diarrhoea (which will often contain blood and mucus - dysentery), painful tummy (abdominal) cramps and high temperature (fever). The symptoms tend to last for around five to seven days.
Symptoms can be severe in some people, particularly the young and the elderly. The diarrhoea can be so bad that it can lead to lack of fluid in the body (dehydration). You should consult a doctor quickly if you suspect that you (or your child) are becoming dehydrated. Mild dehydration is common and is usually easily reversed by drinking lots of fluids. Severe dehydration can be fatal unless quickly treated because the organs of your body need a certain amount of fluid to function.
Dehydration is more likely to occur in:
Dehydration in adults is more likely to occur in:
Shigella is usually diagnosed after a sample of your stool is sent to the laboratory for testing. If you have gastroenteritis - an infection of the bowels (intestines) - with blood and mucus in your diarrhoea, you should see a doctor who can arrange for a sample of your stools (faeces) to be tested.
Antibiotics are used to treat shigella infection in children. This is one of the few times that antibiotics are used to treat infections of the bowels (intestines), called gastroenteritis. It may help to reduce the chance that your child passes on shigella infection to someone else and also may help to reduce the number of days that your child suffers from their symptoms.
The usual antibiotic used is ciprofloxacin. However, the antibiotic may vary depending on advice that your doctor has received from the laboratory specialist who has performed tests on your stool (faeces) sample.
You should also encourage your child to take plenty of fluids. The aim is to prevent lack of fluid in the body (dehydration). The fluid lost in their sick (vomit) and/or diarrhoea needs to be replaced. Your child should continue with their normal diet and usual drinks. In addition, they should also be encouraged to drink extra fluids. However, avoid fruit juices or fizzy drinks, as these can make diarrhoea worse.
Babies aged under 6 months are at increased risk of dehydration. Breast- or bottle-feeds should be encouraged as normal. You may find that your baby's demand for feeds increases. You may also be advised to give extra fluids (either water or rehydration drinks) in between feeds.
Rehydration drinks may be suggested by a healthcare professional for children at increased risk of dehydration (see above for whom this may be). They are made from sachets available from pharmacies and on prescription. You should be given instructions about how much to give. Rehydration drinks provide a perfect balance of water, salts, and sugar. The small amount of sugar and salt helps the water to be absorbed better from the gut into the body. Do not use home-made salt/sugar drinks, as the quantity of salt and sugar has to be exact.
If your child vomits, wait 5-10 minutes and then start giving drinks again, but more slowly (for example, a spoonful every 2-3 minutes). Use of a syringe can help in younger children who may not be able to take sips.
Note: if you suspect that your child is dehydrated, or is becoming dehydrated, you should seek medical advice.
If your child is mildly dehydrated, this may be treated by giving them rehydration drinks. Your doctor or nurse will advise about how to make up the drinks and about how much to give. This can depend on the age and the weight of your child. If you are breast-feeding, you should continue with this during this time. Otherwise, don't give your child any other drinks unless the doctor or nurse has said that this is OK. It is important that your child should be rehydrated before they have any solid food.
Sometimes a child may need to be admitted to hospital for treatment if they are dehydrated. Treatment in hospital usually involves giving rehydration solution via a special tube called a 'nasogastric tube'. This tube passes through your child's nose, down their throat and directly into their stomach. An alternative treatment is with fluids given directly into a vein (intravenous fluids).
Correcting any dehydration is the first priority. However, if your child is not dehydrated (most cases), or once any dehydration has been corrected, then encourage your child to have their normal diet. Do not 'starve' a child with shigella infection. This used to be advised but is now known to be wrong. So:
You should not give medicines to stop diarrhoea to any child under 12 years old. They sound attractive remedies, but are unsafe to give to children, due to possible serious complications. Also, children aged over 12 with shigella should not be given these medicines. This is because they may make symptoms worse. However, you can give paracetamol or ibuprofen to ease the discomfort of a high temperature or tummy (abdominal) pains. Ibuprofen should be used cautiously in children who are dehydrated and paracetamol is probably a better choice in these circumstances.
Probiotics are generally not recommended for children with gastroenteritis or food poisoning from any cause. This may change if further research shows that they are helpful.
Antibiotics are used to treat shigella infection in adults. The usual antibiotic that is used is ciprofloxacin. However, the antibiotic may vary depending on advice that your doctor has received from the laboratory specialist who has performed tests on your stool (faeces) sample.
The aim is to prevent lack of fluid in the body (dehydration), or to treat dehydration if it has developed. (Note: if you suspect that you are dehydrated, you should contact a doctor.)
For most adults, fluids drunk to keep hydrated should include water, fruit juice and soups. It is best not to have drinks that contain a lot of sugar, such as cola or pop, as they can sometimes make diarrhoea worse.
Rehydration drinks are recommended in people who are frail, or over the age of 60, or who have underlying health problems. They are made from sachets that you can buy from pharmacies. (The sachets are also available on prescription.) You add the contents of the sachet to water. Rehydration drinks provide a good balance of water, salts, and sugar. The small amount of sugar and salt helps the water to be absorbed better from the gut (intestines) into the body. They do not stop or reduce diarrhoea. Do not use home-made salt/sugar drinks, as the quantity of salt and sugar has to be exact.
It used to be advised to 'starve' for a while if you had infection of the bowels (intestines), called gastroenteritis. However, now it is advised to eat small, light meals if you can. Be guided by your appetite. You may not feel like food and most adults can do without food for a few days. Eat as soon as you are able but don't stop drinking. If you do feel like eating, avoid fatty, spicy or heavy food. Plain foods such as wholemeal bread and rice are good foods to try eating.
Antidiarrhoeal medicines should not be used if you have confirmed shigella infection or if you are passing blood and mucus in your stools. Paracetamol or ibuprofen are useful to ease a high temperature, headache or tummy (abdominal) cramps.
Note: if you are receiving treatment for shigella infection and your condition is not improving within 48 hours, or if your condition worsens, you should contact your doctor or arrange for urgent medical review as needed. You should also urgently see a doctor:
The same applies for your child.
If you (or your child) have shigella, the following are recommended to prevent the spread of infection to others:
If you have shigella infection and you work with vulnerable groups of people such as the elderly, the unwell or the young, you should inform your employer. Your doctor also has the duty of reporting shigella infection to your local public health authority.
In general, good hygiene is essential to prevent the spread of many infections to others and to reduce your chance of picking up infections from others. Hand washing is the most important thing that you and your child can do. In particular, always wash your hands and dry them thoroughly, and teach children to wash and dry theirs:
If you smoke, you should also wash your hands before smoking. The simple measure of washing and drying hands regularly and properly is known to make a big difference to the chance of developing many infections.
In addition to this, when travelling to areas with poor sanitation, you should avoid eating or drinking the following to help reduce your chance of getting shigella infection. This is because shigella is often passed on by drinking contaminated water or eating food prepared using contaminated water. Avoid:
Sealed bottled water, tea, coffee and alcohol are thought to be safe to drink.
Men who have sex with men should wash their hands after touching a partner's back passage (anus) or coming into contact with a condom used during anal sex. Mouth to anus contact (also known as 'rimming') is very high-risk and should be avoided.
Studies are underway throughout the world, looking at developing a vaccine that may be able to prevent shigella infection.