Bovine Viral Disease Virus Research Articles

Investigation of border disease and bovine virus diarrhoea in sheep from 76 mixed cattle and sheep farms in eastern Switzerland

The purpose of this study was to examine the occurrence of sheep persistently infected with Border disease virus (BDV) on 76 mixed cattle and sheep farms and whether seroconversion to BDV infection occurred in cattle of these farms. Seroprevalence of BDV and bovine viral disease virus (BVDV) infection in sheep was also investigated. Quantitative RT-PCR for pestivirus detection and an ELISA to detect pestivirus antibodies were used in 2'384 and 2'291 ovine blood samples, respectively. Another 27 seropositive sheep from ten flocks underwent serum neutralization testing to differentiate between BDV and BVDV antibodies. A BDV titre that was at least four times higher than the BVDV titre was interpreted as the result of BDV infection. Titres against BVDV were interpreted in an analogous fashion. All examined sheep were pestivirus-negative, 310 sheep were seropositive, 119 had an indeterminate titre and 1'862 were seronegative. The flock seroprevalence ranged from 0.0 to 73.9 %. Three of the 27 flocks that underwent serum neutralization testing were interpreted as BDV-infected because of 6 sheep with higher BDV titres, and 6 flocks were interpreted as BVDV-infected because of 14 sheep with higher BVDV titres.

Phylogenetic analysis and characterization of Korean bovine viral diarrhea viruses

Thirty-six bovine viral disease viruses (BVDVs) were identified in bovine feces (n=16), brains (n=2), and aborted fetuses (n=18) in Korea. To reveal the genetic diversity and characteristics of these Korean strains, the sequences of their 5′-untranslated regions (5′-UTRs) were determined and then compared with published reference sequences. Neighbor-joining phylogenetic analysis revealed that most of the Korean viruses were of the BVDV subtypes 1a (n=17) or 2a (n=17). The remaining strains were of subtypes 1b (n=1) and 1n (n=1). This analysis indicates that the 1a and 2a BVDV subtypes are predominant and widespread in Korea. In addition, the prevalence of BVDV-2 was markedly higher in aborted fetuses than in other samples and was more often associated with reproductive problems and significant mortality in cattle.

Giraffe strain of pestivirus: its taxonomic status based on the 5'-untranslated region.

The 5'-untranslated region (5'-UTR) of the 'Giraffe' strain of pestivirus was sequenced for comparison with those of other pestiviruses from cattle, sheep, goats, and swine. A phylogenetic tree constructed with these strains suggested that the 'Giraffe' strain was allocated to a new taxon. This observation was also confirmed by a newly proposed method based on palindromic nucleotide substitutions (PNS) at the three variable regions in the 5'-UTR. Other reported pestivirus strains isolated from deer were assigned as bovine viral disease virus (BVDV)-1 according to the PNS as well as phylogenetic analysis, suggesting that BVDV-1 strains can cross-infect deer as well as cattle, sheep, goats, and swine, and that wild deer may serve as a reservoir of BVDV-1. We also identified the genovar of a deer isolate, SH9/11, as BVDV-1c by the PNS method.

Alimentary and Respiratory Tract Lesions in Eight Medically Fragile Holstein Cattle with Bovine Leukocyte Adhesion Deficiency (BLAD)

Lesions in the alimentary tract were studied in eight medically fragile Holstein cattle homozygous for the bovine leukocyte adhesion deficiency (BLAD) allele as determined by polymerase chain reaction and restriction endonuclease analysis. These cattle received institutional medical care but died or were euthanatized because of chronic debilitation associated with diarrhea (6/8) and pneumonia (4/8). The six cattle with diarrhea had acute (n = 3) or chronic (n = 3) intestinal ulcers, but the other two remained relatively healthy for 3 years and did not develop intestinal tract ulcers. Ulcerated areas were present in the small intestine in six animals, and two of these also had ulcers in the large intestine. Ulcers were covered by thick exudates that, in chronic lesions, partially occluded the intestinal lumen. Intramural and serosal fibrosis also contributed to lumen constriction. Pseudomonas aeruginosa was isolated from the intestine of four cattle. Bovine viral disease virus and Salmonella were not isolated from the five cattle that were tested. Respiratory tract lesions consisted of dense infiltrates of neutrophils in bronchi, bronchioles, and alveoli. This study suggests that intestinal lesions are integral to the demise of BLAD cattle that receive intensive medical care and that neutrophils do infiltrate the lung and enter airway lumina, despite the adhesion deficiency.