Shigella

Shigellosis is an infection caused by a bacterium called Shigella.

Symptoms

The symptoms usually include:

• diarrhoea
• abdominal pain
• fever
• nausea
• vomiting
• headaches.

Sometimes the diarrhoea can contain blood and mucus.

Symptoms usually start from 24-72 hours after a person becomes infected, but this can be longer in some cases. Most people are sick from 4 to 7 days. Sometimes this can be longer. Some people do not show any symptoms at all. Dehydration can be a complication in young children and the elderly.

How shigellosis is spread

Shigella is easily spread from person-to-person by the faecal-oral route, by direct or indirect contact with faecal matter. This commonly occurs if hands are not washed properly, particularly after going to the toilet or changing nappies.

Certain types of sexual activity, such as oral-anal sex, allow the transmission of Shigella from person-to-person. Shigella infections may also be acquired from eating food or drinking water contaminated with the bacteria either through poor hand hygiene or water contaminated with sewerage.

A person can have Shigella present in their faeces for some weeks with no symptoms and still pass infection on to others.

Who is at risk of infection

Shigella can infect anyone. Overseas travellers, people living in conditions of poor hygiene, children, and men who have sex with men are at greatest risk. Infants, the elderly, and people with weak immune systems are more likely to have severe illness. People living in the same household as a person with Shigella are also at risk.

Diagnosis

Diagnosis of shigellosis requires the isolation of Shigella bacteria from a faecal specimen. Your doctor may order this test if you have symptoms.

Treatment

Antibiotics are usually prescribed to reduce the severity and length of illness, and to reduce the amount of time a person is infectious. Most people usually recover with rest and extra fluids.

Prevention

Hand washing

Hand washing is a very effective way of preventing cross-contamination and person-to-person spread of Shigella.

Hands should be washed with soap and running water for 30 seconds:

• before preparing food
• between handling raw and ready to eat food
• before eating
• after going to the toilet or changing nappies.

Safe food handling

Adopting safe food handling techniques can effectively prevent the spread of Shigella.

Remember to follow these food safety rules:

• wash raw fruit and vegetables before eating them
• keep food preparation areas and utensils clean
• use separate cutting boards and utensils when preparing raw foods and ready-to-eat foods
• thoroughly cook all raw food, particularly poultry and eggs
• avoid using cracked or dirty eggs
• in the fridge, keep raw foods on a lower shelf than ready-to-eat foods to avoid cross contamination
• keep food below 5°C or above 60°C to prevent bacteria growing
• reheat food until the internal temperature is at least 75°C.

Safe sexual practices

People who have shigellosis should not have sex where there is any contact with the anus, to avoid transmitting Shigella to the mouth.

Advice for travellers

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 thoroughly cooked and eaten while hot.

Staying home from work or school

People with Shigella infections should not attend school or work until their diarrhoea has completely stopped.

Children should not attend childcare until they have been free of symptoms for at least 24 hours. People who work at healthcare facilities, childcare centres, schools and food handlers should not work until they have been free of symptoms for at least 48 hours.

More information

Shigellosis a notifiable condition. For more information on Shigella infections contact your doctor or call the Health Protection Service, Communicable Disease Control Information Line during business hours on 02 5124 9213.

Acknowledgement

• Heymann DL, 2015, Control of Communicable Diseases Manual, 20th edition.