Situação da leptospirose em bovinos destinados ao abate no Triângulo Mineiro: sorologia, isolamento e epidemiologia

Abstract

The first chapter was called "General Considerations", in which have a brief review of the literature about what was covered in the thesis. In the second chapter, the objective was to identify the frequency of anti-Leptospira antibodies and to evaluate the epidemiological aspects of bovine leptospirosis in the herds of the Triângulo Mineiro and Alto Paranaíba areas. A total of 372 blood serum samples were collected from male and female cattle from 15 farms located in 12 different municipalities in the Triângulo Mineiro and Alto Paranaíba. Samples were submitted to the microscopic Soroagglutination (MAT) test, using 16 serogroups with 23 serovars of Leptospira spp .. Among the samples evaluated, 267/372 (71.8%) were reagents at titre ≥ 100, mainly for are the serogroups Sejroe, Tarassovi and Hebdomadis. In the titration MAT, 178/267 (66.7%) reactant samples had a higher frequency of titers ≥ 200 for the serogroups Tarassovi (99/267 - 37.1%), Sejroe (43/267-16, 1%), Hebdomadis (15/267 - 5.6%). Among the serovars present in high titres by the most frequent serogroup, Guaricura and Hebdomadis, are not found in vaccines marketed in Brazil, while Tarassovi is found in only two commercial brands. It is believed that these serovars may be transmitted between cattle or other domestic and wild species by environment contamination with urine from infected animals. Thus, it is concluded that leptospirosis in the Triângulo Mineiro and Alto Paranaíba, is present in high frequency in cattle, being caused by non-specific serogroups or that are not present in the national vaccines, necessitating more effective control measures. In the third chapter, the isolation and serological and molecular characterization were performed of a strain of Leptospira from the urine of a male bovine destined to slaughter without changes in ante-mortem examination was carried out. The isolated strain was designated UFU02, being the first report of isolation of Leptospira kirschneri serogrupo Grippotyphosa in cattle in the state of Minas Gerais, Brazil. The identified serogroup is most frequently found in wild species, highlighting the importance of isolates to know the epidemiological aspects of the disease and to establish more efficient prophylactic methods, preventing the transmission of the disease to domestic animals and humans. In the fourth chapter, the objective was to evaluate the reactivity to the MAT of 372 blood serum samples from the Triângulo Mineiro and Alto Paranaíba, with and without the addition of strain UFU02 in the panel of antigens of reference strains. In the test using only reference strains (MATREF), 187/372 (50.26%) were reagents for at least one of the strains tested, whereas in the test with the isolated strain (MAT REF + ISO), 196 / 372 (52.68%) were reactants for at least one of the reference strains and local isolates tested, there being no coagglutination for the same serogroup between local and reference strain. It was concluded that the inclusion of the local strain of the Grippotyphosa serogroup in the MAT revealed a non-significant increase of 2.4% (p> 0.05) in the number of cattle identified as seroreactive, requiring the inclusion of additional strains of local isolates in the panel of MAT antigens. In the fifth chapter are the "final considerations" on thesis, including the conclusions for all chapters.