Prospective serological study of leptospirosis in southern Spain.

This article reports data concerning a serosurvey carried out in Southern Spain to assess the current epidemiological status of a population exposed to risk of leptospirosis. Microagglutination and IgM-EIA tests were carried out on sera from a sample of workers in agriculture-related occupations, exposed to marsh waters. A cohort of 197 workers were followed for a year in an active surveillance program to evaluate seroconversion (laboratory confirmed leptospirosis). The results have shown for the cohort a density of incidence: 6.4 x 100 persons per year, and for the reference population an accumulated incidence of 41.25/100,000. Prevalence rates (P) were 21.3 x 100 and 144 x 10(5) for the cohort and population respectively. Rates were higher in cray-fishers (P: 62.7%), rice-workers, and butchers. This is the first report identifying cray-fishers as a high risk group for leptospirosis, and the reporting of human contamination by Australis serogroup in Spain.