Recent increase in Shigella cases

31 July 2017

The Communicable Disease Control Branch (CDCB) has identified a recent marked increase in cases of Shigella infection in the following regions:

  • Port Augusta
  • Ceduna
  • Far North
  • West Coast.

There is also a current outbreak of shigellosis in the Northern Territory.

About Shigella infection

Shigellosis is highly infectious and spread by direct faecal-oral transmission or indirectly via fomites and flies. The infectious dose can be as low as 10-100 organisms. The incubation period is 1-3 days. Cases of shigellosis present with diarrhoea (which may contain blood and mucus), stomach cramps, fever and vomiting. Duration of illness is usually 3-4 days but people can shed bacteria for up to four weeks after resolution of symptoms. This presents a high risk of ongoing transmission, particularly where overcrowding and poor sanitation occur.

If you suspect your patient has Shigella infection

Doctors are asked to:

  • Take faecal samples for culture and PCR for bacteria, parasites, viruses from all patients who present with symptoms consistent with infective gastroenteritis.
  • Ensure that treatment with appropriate antibiotics as per current Therapeutic Guidelines: Antibiotic is prescribed. Shigellosis is one of the few situations when antibiotics are recommended for gastroenteritis. Given the very low infectious dose, use of antibiotics in cases of Shigella infection is important to reduce the duration of infectivity and thus reduce the risk of transmission. Antibiotics also reduce the duration of symptoms.
  • Encourage people to use good personal hygiene and hand washing to reduce the risk of transmission.
  • Ask about other household contacts who may be unwell, and consider possible common sources of infection.
  • Exclude people with diarrhoea from school, childcare and workplace until diarrhoea-free for 24 hours.
  • Exclude commercial food handlers from work until diarrhoea-free for 48 hours.
  • Advise other people with diarrhoea not to prepare food for others until diarrhoea-free for 48 hours.
  • Notify cases to CDCB.


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