Paradigm of coinfection with viral and bacterial agents causing bovine respiratory disease complex (BRDC) in Central Serbia

Abstract

Viral and bacterial agents causing bovine respiratory disease complex (BRDC) were examined over a five-year period (2015-2019). Thirty-eight farms of beef and dairy cattle from Central Serbia which showed symptoms of BRDC were observed. A total of 118 nasal swab specimens collected from diseased bullocks (n=55), cows (n=18) and calves (n=45) were chosen for the isolation of bacteria and identification by aerobic cultivation. The most commonly isolated bacterial pathogen was Pasteurella multocida (72.88% positive samples). Disk-diffusion method (antibiogram) showed that Amoxiclav and Enrofloxacin were the most efficient antibiotics against Pasteurella multocida isolates (66.67% and 54.17%, respectively). From all examined samples, using the Real Time RT-PCR and PCR methods, we determined the genome sequences of bovine respiratory syncytial virus (BRSV-34.78% of tested samples (8/23), bovine viral diarrhea virus (BVDV, in 34.37% (11/32) and Mycoplasma spp. in 33.33% (8/24). The genome of BoHV-1 virus was not detected in any of the 19 samples tested by Real Time PCR method.

Keywords

• bovine respiratory disease complex (brdc)
• viruses
• bacteria
• mycoplasma spp.
• molecular methods
• isolation
• resistance