[Epidemiologic study of a whooping cough outbreak in Rincón Grande, Veracruz]

An outbreak of whooping cough occurred in February 1988 in the town of Rincon Grande, borough of Santa Ana Atzacan, Veracruz. The objectives of this study were: to corroborate the presence of infection by Bordetella pertussis, to survey the immunizational status against this organism in this population, to identify the etiologic agent involved and the main epidemiologic characteristics of the outbreak. A descriptive study of the cases with the known population as well as a study of the cases and controls to identify the risk factors associated with illness were performed. Among the 461 inhabitants of the town of Rincon Grande, Veracruz, 85 cases were detected giving an attack rate of 18.4 per 100 inhabitants. The outbreak lasted 13 weeks with the highest incidence occurring from the 7th to the 13th of January 1988. The 7 to 11 month old group was the age group most affected having a rate of attack of 85%. The rate of secondary attacks was greater at the intrafamiliar level than at the scholastic level. The main symptoms included: the paroxysmal cough, fever, stridor, epistaxis and conjunctival hemorrhage. Among the complications found were: pneumonia, hemotympanus and dehydration; 84% of the affected children showed leukocytosis and lymphocytosis. The determination of serum B. pertussis antibody levels, demonstrated high levels in 60% of the paired samples. In 14% of the patients there was serologic evidence of an association with an adenovirus infection. The study of the cases and the controls revealed that living with 10 or more persons in the same room, and that having an intrafamiliar contact represented a greater risk for acquiring the disease (odds ratio = 21, P less than 0.05). The immunization survey revealed low coverage (6%) in this locale.