Epidemic cholera in Latin America, 1991-1993: implications of case definitions used for public health surveillance.

This report presents the various cholera case definitions used by the affected countries of Latin America, shows the numbers of cholera cases and deaths attributable to cholera (as reported by Latin American countries to PAHO through 1993), and describes some regional trends in cholera incidence. The information about how cholera cases were defined was obtained from an October 1993 PAHO questionnaire. In all, 948429 cholera cases were reported to PAHO by affected Latin American countries from January 1991 through December 1993, the highest annual incidences being registered in Peru (1991 and 1992) and Guatemala (1993). The case-fatality rate over the three-year period, and also in 1993, was 0.8%. A general downward trend in the incidence of cholera was observed in most South American countries, while the incidence increased in most Central American countries. A good deal of variation was noted in the definitions used for reporting cholera cases, hospitalized cholera cases, and cholera-attributable deaths. Because of these variations, broad intercountry comparisons (including disease burden calculations and care quality assessments based on case-fatality rates) are difficult to make, and even reported trends within a single country need to be evaluated with care. The situation is likely to be complicated in the future by the arrival of V. cholerae O139 in Latin America, creating a need to distinguish between it and the prevailing O1 strain. For purposes of simplicity, wide acceptance, and broad dissemination of case data, the following definitions are recommended: Confirmed case of O1 cholera: laboratory-confirmed infection with toxigenic V. cholerae O1 in any person who has diarrhea. Confirmed case of O139 cholera: laboratory-confirmed infection with toxigenic V. cholerae O139 in any person who has diarrhea. Clinical case of cholera: acute watery diarrhea in a person over 5 years old who is seeking treatment. Death attributable to cholera: death within one week of the onset of diarrhea in a person with confirmed or clinically defined cholera. Hospitalized patient with cholera:a person who has confirmed or clinically defined cholera and who remains at least 12 hours in a health care facility for treatment of the disease.