National case definition: Cholera

Date of last revision/review: May 2008.

National notification

Only confirmed cases of disease should be notified.

Type of surveillance

Routine case-by-case notification to the federal level

Case classification

Confirmed case

Clinical evidence of illness with laboratory confirmation of infection through isolation of cholera toxin producing Vibrio cholerae serotype O1 or O139 from vomitus or stool.

Probable case

Clinical evidence of illness in a person who is epidemiologically linked to a confirmed case.

Laboratory comments

Further strain characterization, including antibiotic susceptibility testing, is indicated for epidemiologic, public health and control purposes.

Clinical evidence

Cholera is characterized by acute watery diarrhea and/or vomiting. The severity of illness may vary.

ICD code(s)

ICD-10 code(s)

ICD-9 code(s)

Type of international reporting

Under Article 6 of the International Health Regulations (IHR) (2005), each State Party shall notify the World Health Organization (WHO) by way of the IHR National Focal PointFootnote 1, and within 24 hours of assessment of public health information, of all events which may constitute a public health emergency of international concern within its territory in accordance with the decision instrument (Annex 2 of the IHRFootnote 2), as well as any health measure implemented in response to those events.

Note: If event does not meet the criteria for notification under Article 6 of the IHR, then other IHR-related reporting requirements may still apply with WHO and/or other States Parties, including those under Art. 7 (information-sharing during unexpected or unusual public health events), Art. 8 (consultation with WHO on public health events), Art. 9 (any public health risk that may cause international disease spread), Art. 10 (requests for verification from WHO), and Art 44 (collaboration and assistance).


In order to have a high reporting specificity, the WHO limits the case definition of cholera to those aged ≥ 5 years.

Illnesses caused by strains of V. cholerae other than toxigenic V. cholerae O1 or O139 should not be reported as cases of cholera.

Probable case definitions are provided as guidelines to assist with case finding and public health management, and are not for national notification purposes.


Case definitions for diseases under national surveillance. CCDR 2000;26S3. Retrieved May 2008, from

Centers for Disease Control and Prevention. MMWR 1997. Case definitions for infectious conditions under public health surveillance Vol 46 (No.RR-10):[p10]. Retrieved February 20, 2017 from

Communicable Diseases Network Australia. 2004. Australian national notifiable diseases case definitions - Cholera. Retrieved February 20, 2017

World Health Organization. Department of Communicable Disease Surveillance and Response (October 1999). WHO Recommended Surveillance Standards. 2nd ed. WHO/CDS/CSR/ISR/99.2. Retrieved on May 29, 2008, from

World Health Organization. International Health Regulations (2005). 3rd ed. Geneva, 2016, from


Footnote 1

In Canada, the IHR National Focal Point is located at the Public Health Agency of Canada.

Return to footnote 1 referrer

Footnote 2

IHR Annex 2 Decision Instrument is on pages 43-46 of the IHR Third Edition (2005):

Return to footnote 2 referrer

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