Co-existence of bovine viral diarrhea and border disease viruses in a sheep flock suffering from abortus and diarrhea

Abstract

Pestivirus infections have a huge economic impact on livestock production. In 2014, an aborted fetus from a sheep flock suffering from abortus and diarrhea was submitted for virological diagnosis. Due to the positive result of the sample for pestivirus and continuing clinical symptoms in the flock, all of the animals were sampled individually. Blood samples for serum and peripheral blood mononuclear cells were collected from 93 animals (5 rams, 26 lambs, and 62 sheep). During sampling 1 ocular and 4 rectal swab samples were obtained from lambs that had a clinical eye problem and diarrhea, respectively. Additionally 5 aborted fetuses were submitted after the initial sampling. Thirteen of the 93 blood samples tested positive for pestivirus by antigen-detection ELISA. Propagation of noncytopathogenic virus was detected in blood samples from 6 lambs and in 1 aborted fetus sample by using the indirect immunoperoxidase monolayer assay. Pestivirus RNA was detected in 10 of 13 samples by RT-PCR employing pan-pestivirus primers. Border disease virus (BDV) RNA was identified with PBD1/PBD2 specific primers in all 10 samples that tested positive for pan-pestivirus primers. Differentiating RT-PCR further identified BVDV-1 sequences in 3 of the 10 samples. The Sequenced BDV strain (KY-57) was located in the cluster of BDV-7 (Aydin-like) while the BVDV strain was close close to BVDV-1c. The results of this study highlight the possibility of dual infection in sheep with BDV and BVDV-1.