An epidemic of disease due to serogroup B Neisseria meningitidis in Alabama: report of an investigation and community-wide prophylaxis with a sulfonamide.

An epidemic of disease due to sulfonamide-sensitive serogroup B Neisseria meningitidis occurred in 1975-1976 in southwestern Alabama. Ten cases occurred in a circumscribed area and resulted in an annual attack rate of 20 cases per 100,000 population. None of the cases were in siblings, and none of the patients had had direct contact with each other. A case-control household study suggested that crowding and person-to-person transmission via carriers may have been contributing risk factors. Seven of the patients were from a triracial ethnic group concentrated in a small isolated rural community within the epidemic area. When three additional cases occurred in this community, a program of community-wide prophylaxis was undertaken as an epidemic control measure, and a large portion of the population participated. No serious side effects were reported. Carrier surveys before and after treatment indicated that compliance with the drug regimen was good and that the drug regimen was associated with a sharp reduction in carriage of N. meningitidis. No cases occurred in the treated population in the five months after treatment.