From February 1993 until October 1996, 547 blood samples were collected from mares with reproductive problems in six farms of the state of Rio de Janeiro, Brazil, and tested by the microscopic agglutination test (MAT) with live antigens for antibodies to seven leptospira serovars. A total of 235 positive reactions (42.96%) at a minimum serum dilution of 1:100 were observed against one or more serovars, which in comparison to other studies developed in Brazil, may be considered as a high prevalence. On mares with anti-leptospiral antibodies, the predominant serovar was icterohaemorrhagiae, reactive on 102 (43.40%) samples, followed by 64 (27.23%) reactions against bratislava, and 34 (14.47%) against pomona. The high prevalence of antibodies to serovar icterohaemorrhagiae observed in this study could have been expected, because in Brazil about 36% of the population of the maintenance host of such strain, Rattus norvegicus, are leptospiral carriers, mainly to strains of the Icterohaemorrhagiae serogroup.
Leptospirosis; Abortion; Reproduction; Horses
