Shigella infection fact sheet

What is shigellosis?

Shigellosis is an infection of the bowel caused by the bacteria Shigella. It is usually diagnosed by testing a faecal specimen that has been sent to a laboratory. Sometimes the bacteria may be grown from blood. Shigellosis is a notifiable disease.

What are the symptoms?

Symptoms can include diarrhoea (often with blood, or mucus), stomach cramps, fever, nausea and vomiting.

In most people symptoms usually last a few days to one week.  It may be several weeks before bowel habits completely return to normal.

Some infected people might only have a very mild illness or no symptoms at all.

Symptoms can develop between one to seven days after becoming infected, but more commonly between one to three days.

Usually the infection occurs in the bowel, but occasionally it may spread to blood or other parts of the body. This can be serious and require hospitalisation.

Anyone can get shigellosis, although very young children, the elderly, people with weak immune systems or are malnourished are at greater risk of infection. Men who have sex with men also have a greater risk of being infected.

How is it treated?

People usually recover from shigellosis within a few days and without antibiotic treatment.

Antibiotics are often prescribed by a doctor to treat shigellosis. This can reduce the severity and length of illness, and shorten the time the person is infectious to others.

Anyone with diarrhoea should drink extra fluid to avoid dehydration. Children with diarrhoea who refuse extra fluids should see a doctor. Anyone with prolonged or severe diarrhoea or who has symptoms causing them concern should see a doctor.

Medicines to prevent vomiting or diarrhoea should not be given (especially in children) except when specifically prescribed by a doctor.

How is it spread?

Shigella bacteria are only found in humans. Spread of shigellosis can occur by eating food or drinking water that has been contaminated by very small amounts of faeces from infected people. Flies can transfer Shigella from human waste to uncovered food.

People who have shigellosis can infect others while the Shigella bacteria remain in their faeces. They may carry the bacteria for several weeks and people can still spread the infection even though they appear well. The risk of infection decreases markedly after the diarrhoea has stopped.

Certain types of sexual activity, such as oral-anal sex, allow the transmission of Shigellafrom person to person.

Shigellosis can be caught by travelling to countries where the infection is common.

Very small numbers of the Shigella bacteria are sufficient to cause an infection.

How is it prevented?

Prevention measures for shigellosis include:

• washing hands in warm soapy water after going to the toilet, changing nappies, changing soiled linen and after smoking
• never changing nappies on tables or counters where food is prepared or eaten
• cleaning books, toys, equipment, furnishings, floors, nappy change areas and toilets regularly (including toilet door handles)
• washing raw fruit and vegetables carefully before eating

People with diarrhoea should not prepare or handle food that will be eaten by others.

People travelling to countries where shigellosis is common should also:

• avoid uncooked foods, including fruit and vegetables unless you are able to peel them yourself
• drink bottled or boiled water
• not drink untreated water, including  ice and drinks mixed with water
• avoid eating from street stalls
• ensure hot food is cooked thoroughly and eaten whilst hot.

How is it controlled?

Children in childcare or school should not attend until they have not had a loose bowel motion for at least 24 hours.

Anyone with diarrhoea should not swim, wade or paddle in public pools or other recreational water facilities.

People with diarrhoea who are involved in food preparation or care for others in hospitals, aged care facilities or childcare should not work while they are ill. 

After recovery from shigellosis, it is important to maintain good hygiene and hand washing practices. A person diagnosed with shigellosis that works in these areas may require exclusion from work until two negative stool cultures are obtained. 

This will be done in consultation with Population Health Services and the person's doctor.

Population Health Services can support the response to outbreaks of diarrhoea.

If there are two or more cases in a hospital, childcare centre, aged care facility, or other institution call the Population Health Services Hotline on 1800 671 738.

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