Cholera in metropolitan Manila: foodborne transmission via street vendors

Reported are the results of an unmatched case-control study to determine the risk factors associated with acquisition of cholera in Manila. Cases were patients admitted to the San Lazaro Hospital between July and September 1989 and whose stools yielded Vibrio cholerae O1 on culture. Controls were patients admitted to the same hospital and who had no history of diarrhoea or of having taken antibiotics during the 3 days prior to admission. Of the 158 cases and 158 controls who had bought food from street vendors, cases were more likely to have bought the following items: pansit (rice noodles with shrimp, meat, and vegetables), mussel soup, spaghetti, fish balls, pig blood coagulated with vinegar, and salty brine shrimp with vegetables. Cases were also more likely to lack piped water at home. An unconditional logistic regression analysis indicated that only pansit (OR = 2.15, 95% CI = 1.32-3.51), mussel soup (OR = 2.29, 95% CI = 1.06-4.95), and the absence of piped water at home (OR = 2.70, 95% CI = 1.63-4.46) remained as risk factors. As control measures we recommend stricter implementation of the food sanitation code and the licensing of street food vendors.