USEFULNESS OF VIBRIOCIDAL ANTIBODY TITRAT ION IN VIBRIO-CHOLERAE O1 ENDEMIC AREAS

We made vibriocidal antibody titration in the serum of some population s in Algeria and in Mali either during or between cholera epidemics. T he seropositivity rate was 43.3 % in healthy contacts in Alger in 1990 during an epidemic of cholera. For 12/16 healthy contacts examined tw o times in a 25-day interval, the seropositivity rate increased during the epidemic and the mean of antibody titres rose 8.88 folds. In Cons tantine, 53 % of 195 blood donors had significant titres of vibriocida l antibodies in 1992, 6 years after an epidemic of cholera. The seropo sitivity rate in population seemed decreasing during this year. In Bam ako, 46 % of selected patients had significant vibriocidal antibody ti tres 8 years after the last epidemic of cholera in Mali. Seven of 10 c hildren born after the epidemic had vibriocidal antibodies. These data confirm the persistence of vibriocidal antibodies in population durin g many years. The importance of the seropositivity rate in healthy con tacts and in children born during a non epidemic periode shows that as ymptomatic infection is frequent and that Vibrio cholerae 0:1 may be c irculating in population between epidemics. As part of surveillance of cholera outbreaks in endemic areas, it might be of interest to study on a regular basis the vibriocidal antibody seropositivity rate in pop ulations.