INTERNATIONAL NOTE

Cholera, 2003

Cholera cases due to Vibrio cholerae were reported from all continents except Oceania (Map 1). During 2003, 45 countries officially reported to WHO a total of 111 575 cases and 1894 deaths. The overall number of cases and deaths declined compared with previous years (Figure 1). The overall case-fatality rate (CFR) decreased to 1.74% but remained high among vulnerable groups in high-risk areas, with rates of up to 41%. Africa reported a total of 108 067 cases, accounting for 96% of the global total of officially notified cholera cases. The number of cases reported from the Americas and Asia continued to decline, and Europe notified only imported cases. Globally, however, the actual figures are estimated to be higher owing to underreporting and other limitations of surveillance systems and to the increased size of vulnerable populations.

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Map 1. Countries/areas reporting cholera cases in 2003

The designations employed and the presentation of material on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

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Figure 1. Countries/areas reporting cholera and cases reported, by year, 1993–2003

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Fewer cases occurred in Africa compared with 2002. During 2003, major outbreaks of cholera occurred in the Democratic Republic of the Congo, Liberia, Mozambique and Somalia. WHO  participated in the verification of 57 outbreaks of acute watery diarrhea in 28 countries, of which 73% were confirmed as cholera. Out of 31 events, 20 occurred in the subregions of middle and central Asia, southern Africa and west Africa. AFRO and EMRO countries reported 83% of verified events.

In summary, 2003 saw a decrease in the total number of cases notified worldwide to WHO compared with 2002 (Figure 1). The number of cases notified by Africa still greatly exceeded the number reported from other continents. The overall CFR dropped by 50% compared with 2002. However, inconsistency in the case definition being used should be taken into account.

Compared with 2002, official reports of cases from the Americas and Asia continued to decrease. Great efforts have been made by many countries to contain the spread of cholera, which has contributed to the important decline in numbers overall. However, there are growing concerns about the ever-increasing proportion of vulnerable populations at risk for cholera and outbreaks of other epidemic-prone diarrheal diseases.

Officially notified cases do not reflect the overall burden of the disease, as a result of both underreporting for fear of unjustified travel and trade-related sanctions and other limitations in the surveillance and reporting system. It is paramount that effective public health tools be identified and applied to contribute to the containment of cholera outbreaks in high-risk areas and among vulnerable populations.

Source: WHO Weekly Epidemiological Record, Vol 79, No 31, 2004.

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