Epidemiological characterization of meningococcal disease in a metropolitan area in Southeastern Brazil, 1976-1994

Abstract

INTRODUCTION: Meningococcal disease continues to warrant assessment as to its endemic and epidemic multicausality and temporal trends in various locations. MATERIAL AND METHOD: Based on a standardization of epidemiological investigation of meningococcal disease in the municipality of Rio de Janeiro county, Southeastern Brazil, as from epidemic of the 1970s a study to characterized the epidemiological characteristics of the disease, was realized. The total of 4,155 cases reported between 1976 and 1994 were analyzed in a retrospective, descriptive, and analytical study, using the epidemiological investigation forms issued by the Municipal Health Secretariat. Statistical analysis was performed using the chi², Wilcoxon-Mann-Whitney, and Kruskal-Wallis tests. RESULTS: The study resulted in the definition of three periods, classified as post-epidemic (1976-79), endemic (1980-86), and epidemic (1987-94), differentiated by the incidence rates and the predominant meningococcal serogroup. The mean incidence rates per period in the municipality were 3.51, 1.67, and 6.53 cases/100,000 inhabitants, respectively. Serogroups A and C predominated during the post-epidemic period, B and A in the endemic, and B in the epidemic. CONCLUSION: The mean case fatality rate remained virtually unchanged over time, but it varied by hospital, and during all three periods was lower in the State government reference hospital than in the other hospitals, whetter public or private. The highest incidence and case fatality rates were associated with patients under one year of age, and the risk of acquiring the disease was greater among males. The highest incidence coefficients tended to occur in the same areas of the conunty during the three epidemiological periods, and the shanty-town population was at twice the risk of acquiring the disease.