High and Persistent Carrier Rates ofNeisseria meningitidis, unaccompanied by Cases of Meningitis

Abstract

1. In Chatham naval hospital a carrier rate for agglutinable meningococci of 50 per cent, persisted for over a year, during which period there were no cases of cerebro-spinal meningitis among the naval and military population of the port.2. During the same period the carrier rate at Portsmouth among the contacts to six cases of meningitis was 5 per cent.3. During the year previous to the present Chatham investigation the carrier rate at Chatham was 13 per cent, among the contacts to five cases of C.S.M.4. There was no association of the meningococcus carrier rate with density of population or season of the year.5. The most senior ratings, with the most spacious accommodation, had as high a carrier rate (60 per cent.) as the recruits with the worst sleeping quarters. Ratings of intermediate seniority had an intermediate rate (38 per cent.).6. Agglutination tests indicated that the antigenic composition of the bacterial herd ofN. meningitidischanged rather suddenly, while the total meningococcal carrier rate remained constant.7. Many of the above recent observations are at variance to what was seen at Chatham, and elsewhere, during the Great War. An attempt is made therefore to reconcile the past with the present experiences.Our thanks are due to Surgeon-Commander J. A. O'Flynn, who kindly tested our culture medium and supplied the Portsmouth C.S.M. data, and also to Chief Petty Officer R. Kircher, R.N., Sick Berth Staff, who did all the nasopharyngeal swabbing (in order to keep the personal equation constant), as well as much of the technical laboratory work.