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Bacillary Dysentery

Bacillary Dysentery

22 July 2019

Causative agent

Bacillary dysentery is an intestinal infection caused by a group of Shigella bacteria which can be found in the human gut.

Clinical features

Infection by Shigella may be asymptomatic or only cause mild illness. For patients who develop bacillary dysentery, they commonly present with acute onset of fever, diarrhoea with abdominal cramps and nausea or vomiting. The stool may contain blood and mucus. Complications include toxic dilatation of the large intestine and acute kidney disease.

Young children, travellers to developing countries and men who have sex with men are more likely to acquire bacillary dysentery. People who have weakened immune systems may develop a more serious illness.

Mode of transmission

Bacillary dysentery is transmitted directly by physical contact with the faecal material of a patient or carrier (including during sexual contact), or indirectly through consumption of contaminated food and water. Infection may occur after consuming a small number of the bacteria. Therefore, the disease is highly contagious and many outbreaks are related to childcare settings and schools.

Incubation period

The incubation period is usually 1 - 3 days, but can be up to 7 days.


Infected persons in schools or institutions should be isolated. They should observe personal hygiene to avoid infecting other persons. Treatment includes fluid replacement and antibiotics.


1. Maintain good personal hygiene
  • Perform hand hygiene frequently, especially before handling food or eating, and after using the toilet or handling faecal matter.
  • Wash hands with liquid soap and water, and rub for at least 20 seconds. Then rinse with water and dry with a disposable paper towel or hand dryer. If hand washing facilities are not available, or when hands are not visibly soiled, hand hygiene with 70 to 80% alcohol-based handrub is an effective alternative.
  • Refrain from work or school, and seek medical advice when suffering from gastrointestinal symptoms such as diarrhoea.
2. Maintain good food hygiene
  • Adopt the 5 Keys to Food Safety in handling food, i.e. Choose (Choose safe raw materials); Clean (Keep hands and utensils clean); Separate (Separate raw and cooked food); Cook (Cook thoroughly); and Safe Temperature (Keep food at safe temperature) to prevent foodborne diseases.
  • Drink only boiled water from the mains or bottled drinks from reliable sources.
  • Avoid drinks with ice of unknown origin.
  • Purchase fresh food from hygienic and reliable sources. Do not patronise illegal hawkers.
  • Eat only thoroughly cooked food.
  • Wash and peel fruit by yourself and avoid eating raw vegetables.
  • Exclude infected persons and asymptomatic carriers from handling food and from providing care to children, elderly and immunocompromised people.

* Please visit the website of Centre for Food Safety for more information on food safety.