Estudo longitudinal prospectivo da incidência de enteropatógenos em bezerras em uma propriedade leiteira

Abstract

This study investigated the frequency of group A rotavirus (RV-A), bovine coronavirus (BCoV), Salmonella spp. and diarrheagenic Escherichia coli. Eight hundred and fifty fecal samples were collected from 67 calves at a farm in the city of Martinho Campos/MG. The animals were followed from birth to at least 60 days old. BCoV was detected by semi-nested RT-PCR and RV-A by polyacrylamide gel electrophoresis (PAGE). Virulence factors of Escherichia coli were identified by multiplex PCR. Salmonella spp. was identified by biochemical tests and serotyping of the strains. The first and second weeks of life concentrated the greatest number cases of diarrhea and then decreased progressively. There was a significant difference between the frequency of diarrhea and the presence of rotavirus (p < 0.0001). The bovine group A rotavirus was identified in 49 fecal samples collected from 23 and 15 animals with diarrhea and without, respectively. The first three weeks concentrated the highest number of cases. Bovine coronavirus was found in 93 stool samples from 46 animals. Cases concentrated in animals with two and three weeks old and then decreased. Seventeen colonies of Salmonella spp. were serotyped by FIOCRUZ, two were Salmonella Enteritidis, 14 Salmonella Agona and one Salmonella enterica subsp. Enterica (0:4,5, flagellar structure not detectable). Only one positive animal had diarrhea with seven days of age and serotype Agona was isolated. Of the 850 fecal samples, seven were positive for intimin (eae), seven for K99/STa, seven for Stx1, 36 for Stx1/Intimin, two for Stx1/Stx2/Intimin, 43 for Stx2 and one for Stx2/Intimin.