Page content: Victorian statutory requirement | Infectious agent | Identification | Incubation period | Public health significance & occurrence | Reservoir | Mode of transmission | Period of communicability | Susceptibility & resistance | Control measures | Outbreak measures | Additional sources of information

Victorian statutory requirement

Haemolytic uraemic syndrome (Group A disease) must be notified immediately by telephone followed by written notification within five days.

VTEC and STEC (Group B disease) must be notified in writing within five days of diagnosis.
School exclusion: exclude if required by the Secretary and only for the period specified by the Secretary. Contacts are not excluded.

Infectious agent

Escherichia coli serotypes capable of producing toxins (Shiga-like or Vero-toxins) similar to those of Shigella dysenteriae type 1 are the causative agents. The most important are E. coli O157:H7, E. coli O111:H8 and E. coli O26:H11.

Identification

Clinical features
Illness is characterised by severe abdominal pain and cramping and watery diarrhoea which becomes grossly bloody and lasts five to ten days. Fever is usually mild or absent. Asymptomatic infection can occur.

In children aged less than five years and the elderly, infection may lead to haemolytic uraemic syndrome (HUS). This is a disease characterised by renal failure, a high mortality rate and thrombotic thrombocytopaenic purpura (TTP). HUS and TTP are complications of infection with serotype O157:H7.

Method of diagnosis
Diagnosis is confirmed by isolation of the organism from faeces. Other diagnostic methods may be required including:

• demonstrating the presence of Shiga-like toxins
• serotyping
• DNA probes that identify the toxin producing genes or the presence of the VTEC virulence plasmid.

As screening for VTEC is not routine in Victorian laboratories the test should be specifically requested for persons with bloody diarrhoea.

As a negative stool culture is not exclusionary, HUS should be considered in the presence of the following:

• acute microangiopathic anaemia on peripheral blood smear
• acute renal impairment (haematuria, proteinuria or elevated creatinine level)
• thrombocytopaenia, particularly during the first seven days of illness.

Incubation period

The incubation period is two to eight days, with an average of three to four days.

top of page