Factsheet about shigellosis
Shigellosis is a gastrointestinal infection caused by one of four species of Shigella bacteria: Shigella sonnei, S. flexneri, S. boydii and S. dysenteriae.
S. sonnei: Most common symptoms are diarrhoea (which is sometimes bloody), abdominal pain and cramps, and fever. Nausea and/or vomiting, loss of appetite, headache or malaise can also occur.
S. flexneri: Also causes diarrhoea, abdominal pain and cramps, and fever but is often more severe than S. sonnei infection. Inflammation and ulceration of the lower part of the bowel is also common and illness can be prolonged and more severe.
S. boydii: Can cause diarrhoeal diseases of varying severity, but mostly are similar to those caused by S. sonnei.
S. dysenteriae: This species causes more severe disease than other forms of shigellae with higher death rates. Inflammation and ulceration of the lower part of the bowel occurs in most cases, displaying itself as bloody stools.
Complications of S. flexneri can include reactive arthritis and Reiter’s syndrome (inflammation of the urethra, conjunctivitis and inflamed joints). Complications of S. dysenteriae can include an enlarged colon due to toxins, haemolytic uraemic syndrome (HUS)—which is a type of kidney failure, blood clots and sepsis (invasion of the body by toxins).
Ways to catch shigellosis
Shigellosis is caught by swallowing material contaminated by faeces, either via the hands or on objects which have been in contact with faeces. Infection can also be caught from contaminated food and water. Food-related outbreaks are often caused by infected food handlers and salad items; both are common ways of spreading the infection. Waterborne infection can occur by ingesting drinking or recreational water. Outbreaks most often occur in daycare centres and schools, residential institutions, restaurants, camps, microbiology laboratories and hospitals.
People most at risk
Shigellosis is largely a disease of children, with the highest number of cases reported in children younger than five. Infection occurs most frequently in the summer. People at highest risk include those attending daycare, travellers abroad and men who have sex with men.
Laboratory testing on samples of faeces from infected patients is used to diagnose shigellosis.
Rehydration therapy is given to people who are ill with shigellosis to stop them from becoming dehydrated. Severe illness is treated with antibiotics.
How to avoid getting shigellosis
Safe disposal of faeces and the protection and treatment of drinking and swimming water are important to prevent people from getting shigellosis. Hand-washing, especially after using the toilet or changing babies’ nappies and before preparing or eating food, reduces the risk. Care with food and water while travelling abroad is also important. There is no vaccine currently available to prevent Shigella infection.
What to do if you have shigellosis
People with shigellosis should not attend school or work whilst ill. Children younger than five, food handlers and healthcare staff should stay at home until 48 hours after their symptoms have stopped. If people in these groups have S. dysenteriae infection, because of the severity of the infection, they should stay home until laboratory tests on repeated faecal samples have come back clear.
The information contained in this factsheet is intended for the purpose of general information and should not be used as a substitute for the individual expertise and judgement of healthcare professionals.