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Cholera (Vibrio cholerae O1/O139)
1995 Case Definition

Clinical Description

An illness characterized by diarrhea and/or vomiting; severity is variable.

Laboratory Criteria for Diagnosis

  • Isolation of toxigenic (i.e., cholera toxin-producing) Vibrio cholerae O1 or O139 from stool or vomitus, OR
  • Significant increase in vibriocidal or antitoxic antibodies between acute- and early convalescent-phase sera, OR
  • Significant decrease in vibriocidal antibodies between early and late convalescent-phase sera among persons not recently vaccinated

Case Classification


A clinically compatible illness that is laboratory confirmed


When other cases are known to be occurring, a less than fourfold increase in titer between acute- and convalescent-phase serum may be considered significant. Likewise, a less than fourfold decrease in titer between early and late convalescent-phase sera may be important in these circumstances. Illnesses caused by strains of V. cholerae other than toxigenic V. cholerae O1 or O139 should not be reported as cases of cholera. The etiologic agent of a case of cholera should be reported as either V. cholerae O1 or V. cholerae O139.

Note: Only confirmed cases should be reported by state health departments to the National Notifiable Diseases Surveillance System (NNDSS).