Cholera

Prevention and control of cholera outbreaks: WHO policy and recommendations

Diagnosis

The presence of V. cholerae in stools is confirmed through laboratory procedures. However, a new rapid diagnostic test (RDT), now available, allows quick testing at the patient's bedside. WHO is currently in the process of validating this RDT, to be able to include it on the list of its pre-qualified products.

In the meantime, WHO suggests that all samples tested positive with the RDT are re-tested using classic laboratory procedures for confirmation. Not all cases fitting the WHO clinical case definition need to be tested. Once an outbreak is confirmed, a clinical diagnosis using WHO standard case definition is sufficient1, accompanied by sporadic testing at regular intervals.

Key messages

  • Once Vibrio cholerae has been confirmed, the WHO clinical case definition is sufficient to diagnose cases. After that laboratory testing is required for antimicrobial sensitivity testing and for confirming the end of an outbreak.
  • Rapid diagnostic tests can facilitated early warning and detection of first cases.

1 WHO Standard case definition: A case of cholera should be suspected when:

  • in an area where the disease is not known to be present, a patient aged 5 years or more develops severe dehydration or dies from acute watery diarrhoea;
  • in an area where there is a cholera epidemic, a patient aged 5 years or more develops acute watery diarrhoea, with or without vomiting.

A case of cholera is confirmed when Vibrio cholerae O1 or O139 is isolated from any patient with diarrhoea.

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