A PHYLOGENETIC ANALYSIS OF BOVINE VIRAL DIARRHEA VIRUS SUBTYPES IN DIAGNOSTIC SAMPLES FROM CATTLE IN PENNSYLVANIA
Open Access
- Author:
- Peterson, Ryan
- Graduate Program:
- Pathobiology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- April 02, 2010
- Committee Members:
- Bhushan M Jayarao, Thesis Advisor/Co-Advisor
Bhushan M Jayarao, Thesis Advisor/Co-Advisor - Keywords:
- genome
virus
bovine
pestivirus
Phylogenetic analysis
vaccine
subtype
clinical signs
diagnostic
veterinary
1a
1b
BVDV
2a
2b
mutation
disease - Abstract:
- Bovine Viral Diarrhea (BVD) is an economically important disease in cattle with estimated losses between 10 and 40 million dollars per million calvings per year in the US. BVD is a complex viral disease producing multifocal clinical symptoms. Evidence from previous studies of Bovine Viral Diarrhea Virus (BVDV) in the United States has shown that 1 in 133 BVDV isolates were similar to strains of BVDV routinely used in vaccinations. The purpose of this study was to: 1. Analyze clinical BVDV isolates obtained from samples submitted to the Pennsylvania State University Animal Diagnostic Laboratory for genetic similarity to BVDV vaccine strain subtype. 2. To determine if novel strains and subtypes of BVDV are circulating in vaccinated and unvaccinated cattle and to make inferences about the efficacy of the current vaccines. The 5 prime untranslated region (5’ UTR) of the BVDV genome from BVDV was isolated from clinical samples by reverse transcription polymerase chain reaction (RT-PCR). PCR products were purified and sequenced in both directions using forward and reverse primers. The resulting sequences were compared to known BVDV reference strains representing 10 subtypes of BVDV currently described worldwide. Phylogenetic analysis was used to group isolates based on similarity to known BVDV subtypes. The conclusions of this study describe 5 subtypes of BVDV identified in the study population. The majority of isolates were found to be dissimilar to BVDV strains found in common vaccines for BVDV. An unexpectedly high rate of diversity of BVDV 2b was found in the study population and a diverging phylogenetic grouping from the BVDV 2b was identified as a possible new subtype of BVDV in cattle.