17826 Shigellosis

Overview

Shigellosis is an infection of the bowel caused by bacteria called Shigella. It leads to diarrhoea (often with blood and mucus), stomach cramps, and fever. It spreads very easily from person to person, especially when hands, food, or water are contaminated with tiny amounts of infected poo.

Shigellosis is a common cause of diarrhoea worldwide, especially in areas with poor sanitation or crowded living conditions. In high-income countries like the UK, it is less common overall, but local outbreaks do happen in nurseries, care homes, and among travellers returning from affected regions.

Anyone can get shigellosis, but it is most common in young children, especially those in childcare. It also affects travellers to regions with unsafe water or poor food hygiene, people living in crowded settings, men who have sex with men (in certain outbreaks), and people with weakened immune systems.

Symptoms

Common symptoms

• Frequent loose, watery diarrhoea
• Blood or mucus in the stool
• Stomach cramps and tenderness
• High temperature (fever)
• Feeling sick or vomiting
• A constant urge to go to the toilet (tenesmus)
• Feeling generally tired and achy

Symptoms in children

• The same symptoms as adults, but children can become dehydrated faster
• High fever sometimes causing a seizure (febrile convulsion)
• Lethargy and being unusually floppy or irritable
• Fewer wet nappies or tears when crying (signs of dehydration)

Symptoms in older adults

• More severe watery diarrhoea leading to dehydration
• Confusion or dizziness, especially if fluids are not replaced
• A higher risk of needing hospital care for fluids
• Kidney problems in rare cases

Causes

Main causes

• Shigella bacteria – usually Shigella sonnei, flexneri, boydii, or dysenteriae
• Touching surfaces or objects contaminated with infected faeces, then touching your mouth
• Eating food that was prepared by someone with unclean hands
• Drinking water or ice contaminated with sewage
• Swallowing contaminated water while swimming in pools, lakes, or the sea
• Sexual contact that involves faecal–oral contact

Risk factors

• Young age – especially children under 5
• Travelling to countries with poor sanitation and unsafe water
• Living or working in crowded settings like nurseries, care homes, or refugee camps
• Having a weakened immune system from HIV, chemotherapy, or other conditions
• Taking medicines that reduce stomach acid, which can increase susceptibility
• Having close contact with someone already infected

When to see a doctor

See a doctor urgently if:

• You have bloody diarrhoea or diarrhoea with mucus
• You show signs of dehydration (dizziness, dry mouth, very dark urine, little urine)
• You have a high fever that does not improve with simple measures
• You are pregnant, elderly, or have a weakened immune system
• Symptoms are not improving after a few days or are getting worse

Book a routine appointment if:

• Mild diarrhoea that lasts more than a few days but you can still drink fluids
• You need a fit note for work or school, or you need advice about when it is safe to return
• You have recently travelled abroad and have persistent symptoms

Diagnosis

A doctor can often suspect shigellosis from your symptoms and recent travel or contact history. To confirm the diagnosis, they will usually ask for a stool (poo) sample to be sent to a laboratory. Sometimes a doctor makes a clinical diagnosis without a stool test, especially during a known outbreak.

Tests that may be done

• Stool culture – checking a poo sample for Shigella bacteria
• PCR (polymerase chain reaction) – a molecular test that finds the bacteria's genetic material quickly
• Antibiotic sensitivity testing – if bacteria are grown, to see which antibiotics would work if treatment is needed

What to expect at your appointment

Your doctor will ask about your symptoms, travel history, and any contact with people who have diarrhoea. They may examine your abdomen and check your hydration status. You will be given a stool sample kit with instructions. Results usually come back within 2 to 3 days, but sometimes longer. You do not usually need blood tests unless you are very unwell or have complications.

Treatment

Shigellosis usually clears up on its own within a week. The main treatment is preventing dehydration by drinking plenty of fluids. Antibiotics are sometimes prescribed for people at higher risk of complications, for those with severe symptoms, or to reduce the spread of infection in certain settings. You should not take anti-diarrhoeal medicines without medical advice, as they can make the infection worse.

Self-care at home

• Drink plenty of water and oral rehydration salts (available from your pharmacist) to replace lost fluids and salt
• Rest as much as you can – your body needs energy to fight the infection
• Wash your hands with soap and water after every toilet visit and before preparing or eating food
• Avoid preparing food for others until you have been symptom-free for at least 48 hours
• Do not use public swimming pools or share towels until the diarrhoea has completely stopped
• Stay at home, away from school or work, until you have had no diarrhoea for at least 2 days

Medical treatments

In some cases, especially for young children, older adults, people with weak immune systems, or those with severe symptoms, a doctor may prescribe antibiotics. Antibiotics can shorten the illness and stop the spread of bacteria. However, many people do not need them. The healthcare professional will decide based on the severity of your illness and your personal risk factors. Always finish any prescribed course exactly as given.

Living with this condition

While you recover, your main focus is hydration and rest. You may need to spend a couple of days at home in bed or close to the bathroom. Carry hand sanitiser with you if you cannot wash your hands easily. Keep your bathroom clean, and ideally use a separate toilet if others live with you. Wash soiled clothing and bedding on a hot cycle.

Lifestyle tips

• Take time off work or school until the diarrhoea has stopped for 48 hours
• Avoid swimming or hot tubs for at least 2 weeks after symptoms settle, as you can still carry the bacteria
• Do not visit vulnerable people, such as hospital patients or older relatives, until you are fully clear
• Use your own towels and flannel to reduce the risk of spreading the infection
• If symptoms return after you feel better, contact your doctor – you may need another test

Diet and exercise

Eat a light, bland diet once you feel hungry – boiled rice, toast, bananas, and plain soups are gentle on your stomach. Avoid dairy, fatty or spicy foods, and high-sugar drinks until your bowel settles. Avoid caffeine and alcohol, as these can dehydrate you. When you feel better, return to exercise gradually with short walks before intense workouts.

Mental health and emotional wellbeing

Having a bowel infection can feel embarrassing, unpleasant, and isolating, especially if you need to stay home for a week. It is normal to feel worried about dehydration or spreading the illness. Remember that most people recover completely. If you feel low, anxious, or upset, talk to a friend, family member, or your GP. Getting enough sleep and resting will also help your mood.

Prevention

Yes. The most effective way to prevent shigellosis is thorough and frequent hand-washing with soap and water – especially after using the toilet, before eating, and before preparing food. When travelling, drink bottled or boiled water, eat well-cooked food, and avoid raw vegetables or peeled fruit. Do not swim in water that may be contaminated.

Vaccines

There is no routine vaccine for shigellosis available to the public. Researchers are studying vaccines, but they are not yet approved for general use.

Screening programmes

Screening does not apply to shigellosis. If you have been in contact with someone diagnosed with the infection, a doctor or public health team may recommend a stool test if you develop symptoms, but there is no population screening program.

Complications

If left untreated

• Dehydration and electrolyte imbalance – the most common complication, which can be serious in young children and older adults
• Kidney problems, such as haemolytic uraemic syndrome (HUS), especially with a certain strain of Shigella dysenteriae
• Infection spreading into the bloodstream (bacteraemia), which can be life-threatening for people with weak immune systems
• Seizures in children, caused by high fever
• Reactive arthritis – occasional joint pain and inflammation that can occur a few weeks later
• Ongoing bowel symptoms, such as bloating or changes in bowel habit, lasting weeks after the infection

Long-term outlook

The outlook for shigellosis is very good for most people. With proper hydration and rest, the infection usually clears within a week and leaves no lasting health problems. In more severe cases, especially in vulnerable people, antibiotics and hospital care can help you recover fully. Serious complications are rare, and most people get back to their normal life quickly.

Find support

International organisations

• World Health Organization (WHO) ↗

Local organisations

• NHS – Diarrhoea and vomiting ↗ · United Kingdom

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