STUDIES ON MAJOR BACTERIAL-VIRAL AGENTS ASSOCIATED WITH DIARRHOEA IN CALVES
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Date
2022
Authors
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KARNATAKA VETERINARY, ANIMAL ANDFISHERIES SCIENCES UNIVERSITY, BIDAR
Abstract
Calf diarrhoea is a commonly reported disease of calves caused by multietiological
agents leading to high morbidity and mortality. The present study was
carried out to isolate and characterize predominant bacteria such as E. coli and
Salmonella, and to detect bovine rotavirus and bovine coronavirus in the faecal
samples of diarrhoeic and non-diarrhoeic calves. For this a total of 162 faecal samples
were collected from diarrhoeic and non-diarrhoeic calves under six months of age. In
total, 155 and 8 faecal samples were positive for E. coli and Salmonella respectively.
Duplex PCR was performed to confirm E. coli by targeting the uidA and uspA genes
and uniplex PCR was performed to confirm Salmonella by targeting the invA gene.
The virulence genes of E. coli, namely, fimH, stx1 and stx2 were detected in 94.19%
(146/155), 25.16% (39/155) and 32.25% (50/155), respectively. All the Salmonella
isolates in our study were found to be S. Typhimurium 100% (8/8) and none were S.
Enteritidis. The stn gene was detected in 87.5% (7/8) of Salmonella isolates. All 162
faecal samples were also screened for the presence of bovine rotavirus and bovine
coronavirus by RT-PCR by targeting VP6 and N genes, respectively. Bovine rotavirus
was detected in 47.53% (77 out of 162) samples, whereas none of the faecal samples
were positive for bovine coronavirus.
The antibiogram study by disc diffusion method revealed that the bacterial
species were 100% resistant to metronidazole and polymyxin-B, but susceptible to
ciprofloxacin and co-trimoxazole. The study gave an insight into the major bacterial
and viral etiological profile, antibiogram and virulence potential of bacterial agents
associated with calf diarrhoea.
Key words: Calf diarrhoea, E. coli, Salmonella serovars, bovine rotavirus, bovine
coronavirus, antibiogram