Are there national risk factors for epidemic cholera? The correlation between socioeconomic and demographic indices and cholera incidence in Latin America.

Abstract

From 1991 through 1995, all Latin American countries maintained cholera surveillance systems to track the epidemic that entered the region through Peru in January 1991. These data were used to assess correlations between socioeconomic and demographic indices that might serve as national risk predictors for epidemic cholera in Latin America. Correlations between country-specific cumulative cholera incidence rates from 1991 through 1995 and infant mortality, the Human Development Index [HDI] a numerical value based on life expectancy, education, and income), gross national product (GNP) per capita, and female literacy were tested using the Pearson correlation coefficient. A total of 1,339,834 cholera cases with a cumulative incidence rate of 183 per 100,000 population were reported from affected Western Hemisphere countries from 1991 through 1995. Infant mortality rates were the most strongly correlated with cumulative cholera incidence based on the Pearson correlation coefficient. The HDI had a less strong negative correlation with cumulative cholera incidence. The GNP per capita and female literacy rates were weakly and negatively correlated with cholera cumulative incidence rates. Infant mortality and possibly the HDI may be useful indirect indices of the risk of sustained transmission of cholera within a Latin American country. Cumulative cholera incidence is decreased particularly in countries with infant mortality below 40 per 1000 live births. The lack of reported cholera cases in Uruguay and the Caribbean may reflect a low risk for ongoing transmission, consistent with socioeconomic and demographic indices. Cholera surveillance remains an important instrument for determining cholera trends within individual countries and regions.