Soroprevalencia de leptospirose em bovinos nas mesorregiões sudeste e sudoeste do estado Rio Grande do Sul, Brasil

The presence of anti-leptospira spp. aglutinins in 1360 bovine serum samples was determined in clinically healthy animals from different breeds, at more than three years old. Cattle were raised in intensive systems on 136 farms of 18 counties, 10 located in the southeast Mesoregion and 8 in the southwest Mesoregion of Rio Grande do Sul state, Brazil, from January to March 1999. The sera were tested by the Microscopic Agglutination Technique, and the titles of anti-Leptospira spp. Agglutinins varied from 100 to 3200. In 1360 samples tested 527 (38.75%) were positive. The prevalence of seroreactors to the different serovars was: Hardjo norma 396 (29.12%), Hebdomadis 30 (2.21%), Wolffi 21 (1.54%), Grippotyphosa 16 (1.18%), Pomona 15 (1.10%), Bratislava 12 (0.88%), Tarassovi 9 (0.44%), Sejroe 8 (0.59%), Pyrogenes 7 (0.51%), Autumnalis 6 (0.44%), Fortbragg 4 (0.29%), Australis 2 (0.15%) Icterohaemorrhagiae 1 (0.07%), Sentot 0, Castellonis 0, Canicola 0, Mini Szwajizak 0. The serovar Hardjoprajitino strain norma was the most disseminated in bovine breeds in Southeast and Southwest Mesoregions of Rio Grande do Sul State, Brazil.