Epidemic Disease due to Serogroup C Neisseria meningitidis in Sao Paulo, Brazil

A large urban epidemic of meningococcal disease is occurring in Saõ Paulo, Brazil. Cases were first reported to the Saõ Paulo Health Department at an epidemic rate in June 1971, and the reported incidence of meningococcal disease has remained above the endemic level ever since, with peaks in late 1971 and from July 1972 through the time of our investigation (December 1972). Infants are at greatest risk, although the greatest relative increases in attack rates have occurred in groups older than 15 years. Age-specific attack rates for males and females are the same, except that 20–25-year-old males have had a significantly higher rate. The entire metropolitan area was involved by the second year of the epidemic. The epidemic strain was identified as a sulfonamide-resistant serogroup C Neisseria meningitidis.