Studies on cholera carriers.

Cholera carrier studies in the Philippines in 1964-66 showed a prevalence rate of 21.7% among household contacts of cholera patients, and 8.4% in occupants of houses next door to one where a cholera patient lived, as opposed to 0.34% in the general population. The duration of the carrier state among 19 household carriers isolated for examination varied from 5 to 19 days. The vibrio concentration in the stool of contact carriers was 10(2)-15(5) per gram, as compared with 10(6)-19(9) per ml of rice-water stool in cholera cases.The agglutinin titre increased with time for carriers, as it does for patients. It declined to a very low level 8-12 weeks after recovery, with the exception of one proved long-term carrier.The strains isolated from carriers were identical in all respects, including virulence in infant rabbits, with strains isolated from patients-except that 3 carrier strains were rough.