Persistence of leptospiral agglutinins in Trinidadian survey subjects.
Participants in a survey for leptospiral agglutinating antibodies undertaken in Trinidad, West Indies, in 1977-78, were further monitored for up to 5-and-a-half years. 52 individuals with a titre greater than or equal to 1:400 were matched for age, sex and occupation with seronegative subjects. They were re-bled twice (on average 2.38 and 4.84 years later), and changes of titre were noted. At the first follow-up, 78% of negative controls remained negative, and 22%, showed titre changes. Among the seropositive subjects, 47% showed a fall in titre, 38% showed no change, and in 15% the titre rose. New exposure rates between the original and first follow-up samples were 96/1,000 survey population per year in the controls, and 68/1,000 for the subjects with titres greater than or equal to 1:400. Between the first and second follow-up, 47% of the seropositive subjects lost titre, 40% showed no change, and 13% showed a rise in titre. These data demonstrate that although antibody titres may be maintained for a few years at the same level, or show a loss as is usually expected, about 8.3% of individuals in Trinidad may be infected/reinfected per year. The infection/reinfection rate is an important factor in the epidemiology of leptospirosis.
Everard
C O
CO
Leptospira Laboratory, Lower Collymore Rock, St. Michael, Barbados.
Bennett
S
S
D000293:Adolescent; D000328:Adult; D000373:Agglutinins / Q000276:immunology* / Q000302:isolation & purification; D002648:Child; D003710:Demography; D004812:Epidemiologic Methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007919:Leptospira / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity; D007922:Leptospirosis / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D008297:Male; D014300:Trinidad and Tobago
D000373:Agglutinins