Gastroenteritis Shigella

Overview

Shigella is a type of bacteria that infects the gut and causes an illness often called shigellosis, or Shigella gastroenteritis. Gastroenteritis simply means inflammation of the stomach and bowel. When you catch Shigella, it gets into your bowel and makes it inflamed, which leads to diarrhoea, tummy cramps and fever. It spreads easily from person to person, usually when tiny amounts of bacteria from an infected person's poo get onto hands, food or water and are then swallowed. Most people feel very unwell for a few days but recover fully within about a week with rest and plenty of fluids.

Shigellosis happens worldwide. It is one of the more common causes of bloody diarrhoea, especially in young children, in settings where people live closely together, and in travellers returning from places with poor water and sanitation. In countries with good sanitation it is less common but still occurs in outbreaks.

Anyone can catch it, but it is seen most often in young children (especially those in childcare or school), people travelling to areas with limited clean water and sanitation, people living in crowded settings such as care homes or shelters, men who have sex with men, and anyone with a weakened immune system. Older adults and people with long-term health conditions can become more unwell because they dehydrate faster.

Symptoms

Common symptoms

• Diarrhoea that may be watery at first and later contain blood or mucus
• Tummy cramps and pain, often coming in waves before a bowel movement
• Fever, often with chills and feeling shivery
• Feeling sick or being sick
• Needing to go to the toilet very urgently and often
• A feeling of still needing to go even after you have just been (doctors call this tenesmus)
• Headache, aching muscles and general tiredness
• Loss of appetite

Symptoms in children

• More likely to become dehydrated quickly — watch for fewer wet nappies or trips to the toilet
• Sleepy, floppy or unusually irritable
• Dry mouth, no tears when crying, sunken eyes
• High fever, and occasionally a brief fit (febrile seizure) caused by the fever — this needs urgent medical check
• Refusing drinks or feeds
• Tummy pain that is severe or constant

Symptoms in older adults

• Dehydration can build up fast and cause confusion or dizziness
• Weakness, falls or difficulty getting to the toilet in time
• Existing heart, kidney or diabetes problems can become harder to manage
• Dry mouth, dark urine and passing little urine
• Feeling unusually drowsy or not themselves

Causes

Main causes

• Swallowing Shigella bacteria that have come from the poo of an infected person
• Touching hands, surfaces, toys, door handles or nappies that carry the bacteria and then touching your mouth or food
• Drinking or eating contaminated water, ice, salads, fruit or other food that was handled by someone who is infected
• Sexual contact that involves the mouth and bottom area (oral-anal contact)
• Flies can carry the bacteria from waste to food in some settings

Risk factors

• Being a young child, especially in childcare or school settings
• Living in crowded places such as care homes, shelters or dormitories
• Travelling to countries with limited clean water and sanitation
• Men who have sex with men
• Having a weakened immune system, or taking medicines that lower immunity
• Taking medicines that reduce stomach acid
• Poor access to clean water, soap and toilets

When to see a doctor

See a doctor urgently if:

• Blood or mucus in your poo
• You cannot keep fluids down or are showing signs of dehydration
• A fever that is high or lasting more than a couple of days
• Severe or constant tummy pain
• You are pregnant, have a weakened immune system, or have a long-term condition such as kidney or heart disease
• A baby, young child or older adult who seems to be getting worse

Book a routine appointment if:

• Diarrhoea that is not settling after about a week
• Symptoms that keep coming back
• You need advice about staying off work, school or childcare
• You are worried, or you want to know whether you need a stool test
• You work with food, in healthcare, or in childcare

Diagnosis

A doctor will usually start by asking about your symptoms, how long you have had them, what you have eaten and drunk, and whether you have travelled recently or been in contact with someone who is unwell. They will check how hydrated you are by looking at your mouth, eyes and skin, and may press gently on your tummy. Because Shigella looks similar to other gut infections, the only way to confirm it is with a stool sample (a poo test) sent to a laboratory.

Tests that may be done

• Stool (poo) sample — the main test, which looks for Shigella and other gut germs
• Blood tests, if you are very unwell or the doctor is worried about dehydration or a more serious infection
• Urine tests, to check for dehydration or other problems
• In some cases, a rectal swab (a soft swab taken gently from the back passage)

What to expect at your appointment

You will be given a small pot and asked to bring back a sample of your poo, usually within a day or two. Results often take a few days. In the meantime, the advice is the same: drink plenty of fluids, rest, wash your hands often, and stay away from work, school or childcare until you have been free of diarrhoea for at least 48 hours. Your doctor will contact you if the result shows something that needs treatment.

Treatment

For most healthy people, Shigella gastroenteritis is treated at home. The most important treatment is replacing the fluid and salts you are losing through diarrhoea and vomiting. Antibiotics are not needed for everyone — a doctor may suggest them if you are very unwell, have a weakened immune system, or are at risk of passing the infection to others. There is no need to take anything to stop the diarrhoea unless a doctor or pharmacist advises it, because diarrhoea is one way the body clears the infection.

Self-care at home

• Drink small amounts often — water is fine, and oral rehydration salts (sachets from a pharmacy) are the best way to replace lost salts and sugar
• Keep feeding babies and children as normal; offer extra breastfeeds or drinks
• Rest and stay home until you have had no diarrhoea for at least 48 hours
• Wash your hands with soap and water after every trip to the toilet, and before preparing or eating food
• Do not prepare food for other people while you are unwell
• Clean the toilet, taps, door handles and nappy-changing areas with disinfectant
• Wash soiled clothing and bedding separately at a hot temperature
• Avoid swimming pools for two weeks after your last episode of diarrhoea
• Eat small, plain meals as you feel able — bland foods are gentler, but you do not need to avoid eating

Medical treatments

A doctor will focus first on rehydration. If you are very dehydrated, you may be given fluids through a drip in hospital. Antibiotics may be offered in some situations, such as severe illness, a weakened immune system, or a high risk of spreading the infection to others. Your doctor will decide whether this is right for you, taking into account your health, allergies and local guidance. Medicines that slow down the bowel are generally not recommended without medical advice, as they can make things worse. Always check with a doctor or pharmacist before taking any medicine, including ones you can buy without a prescription.

When is surgery considered?

Surgery is not used to treat Shigella gastroenteritis. Very rarely, a serious complication affecting the bowel could need hospital care, but this is uncommon.

Living with this condition

The first few days are usually the hardest, with frequent trips to the toilet and feeling wiped out. Plan for rest, keep a drink within reach, and don't push yourself back to normal too quickly. Set up a simple routine: drink a little every 15 to 20 minutes, wash your hands every time you use the toilet, and keep a separate towel and flannel for anyone who is unwell. Children may need cuddles, calm reassurance and frequent small drinks. Keep an eye on how much they are weeing and how alert they are.

Lifestyle tips

• Make handwashing a family habit — soap and water for at least 20 seconds
• Keep a bottle of water with you and sip through the day
• Stay off work, school or nursery until 48 hours after the last episode of diarrhoea, and follow local health advice for food handlers, healthcare workers and childcare staff
• Wash fruit and vegetables and be careful with food hygiene when travelling
• Avoid sharing towels, cups and cutlery while unwell
• Rest more than usual for a few days, then build activity back up gently

Diet and exercise

There is no special diet that cures Shigella. The priority is fluids. Eat when you feel hungry, choosing simple foods that sit comfortably — for example rice, bread, pasta, potatoes, soup, bananas or yoghurt. You do not need to avoid dairy unless it upsets you. Avoid very fatty, spicy or sugary foods and alcohol until you feel better. Gentle movement such as walking around the house is fine, but wait until you have been well for a few days before going back to intense exercise, and drink extra fluids if you do.

Mental health and emotional wellbeing

Being unwell with diarrhoea can feel embarrassing, exhausting and isolating, especially if you are worried about accidents or about passing the infection on. Children may be frightened by sudden urges to go to the toilet. It is completely normal to feel low or anxious for a few days. Tell someone you trust how you are feeling, and speak to a doctor if the worry or low mood is not lifting. If you ever feel you cannot cope or have thoughts of harming yourself, contact your local crisis line or emergency services straight away — support is available and you deserve it.

Prevention

Yes — shigellosis is largely preventable, because the bacteria spread through hands, food, water and surfaces. Washing hands well with soap and water after using the toilet, after changing nappies and before preparing or eating food makes the biggest difference. Clean toilet seats and handles regularly, wash soiled clothes separately, and take extra care with food and water when travelling. If you are unwell, staying away from others until 48 hours after your last episode of diarrhoea helps protect them.

Vaccines

There is currently no routine vaccine available against Shigella. Researchers are working on vaccines, but for now prevention relies on hygiene, safe food and clean water.

Screening programmes

There is no screening programme for Shigella. Stool testing is only done when someone has symptoms and a doctor thinks it is needed.

Complications

If left untreated

• Dehydration — the most common and most serious risk, especially in babies and older adults
• Tiredness and weakness lasting longer than the infection itself
• In some people, joint pain, eye irritation or painful urination a few weeks later (doctors call this reactive arthritis) — this usually settles with treatment
• Rarely, a fit (seizure) in a child caused by high fever
• Rarely, the infection can spread beyond the gut, which is more likely in people with weakened immune systems
• Ongoing bowel changes such as looser stools or tummy discomfort for a few weeks after recovery

Long-term outlook

The outlook is good. Most people recover fully within about a week, and the great majority need nothing more than fluids, rest and hygiene. Some people feel tired for a little longer, and a few notice bowel changes for a few weeks, but these usually settle. If you have a weakened immune system or you are caring for a baby or older adult, keep in touch with your doctor — they can help you spot problems early and make sure you are recovering well.

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