INTERVENTION STRATEGIES TO CONTROL VIRAL DISEASES OF CATTLE
Location: Ruminant Diseases and Immunology Research Unit
Title: Genetic diversity and frequency of bovine viral diarrhea virus (BVDV) detected in cattle in Turkey
Submitted to: Comparative Immunology Microbiology and Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 28, 2012
Publication Date: N/A
Interpretive Summary: Bovine viral diarrhea viruses (BVDV) are a group of pathogens that cause infection in cattle. Infection with BVDV results in significant economic loss for dairy and beef producers. BVDV strains can be divided into different groups based on comparison of the hereditary information of each strain. Different BVDV groups are present in different geographic regions of the world. This manuscript reports a study of the BVDV groups present in Turkey. This information is important, as methods to detect and prevent BVDV infection will differ according to which BVDV group is present in the region. The information reported can be used to develop tools for the detection and prevention of BVDV infections that are tailor made for use in Turkey.
Rapid detection and culling of persistently infected animals and efficacious vaccination are key factors to control bovine viral diarrhea virus (BVDV) infections in cattle. The aim of this study was to investigate frequency of detection of persistently infected cattle and examine the diversity of bovine viral diarrhea virus in cattle in Turkey. To this end, 1124 blood samples were collected from animals from 4 different regions in Turkey and analyzed by antigen-capture ELISA. BVDV was detected in samples collected from 13 out of 19 farms surveyed. Of the 26 animals testing positive, 20 were available for testing one month after the original samples were collected. Samples were collected from these animals and tested by ELISA and real-time RT-PCR. Upon retesting, 6 out of 20 samples were found to be positive by both assays. Genomic regions, coding from the viral glycoprotein E2 and the 5' UTR of BVDV, from 19 BVDV isolated from the first set of samples were amplified and sequenced. Phylogenetic analysis indicated that 17 Turkish BVDVs belonged to the BVDV-1 genotype and two belonged to the BVDV-2 genotype. Based on comparison of 5' UTR sequences, 8 strains (strains 5, 6, 10, 11, 12, 13, 17 and 19) belonged to the BVDV1f sub-genotype, 1 strain (strain 8) belonged to the BVDV1i sub-genotype, and one strain (strain 14) belonged to the BVDV1d sub-genotype. One strain (strain 4) was closer to the BVDV1f sub-genotype than to other sub-genotypes, but relatively distant from other BVDV1f sub-genotype strains. The remaining 6 BVDV-1 genotype strains (strains 1, 2, 3, 7, 9, 18) belonged to a novel sub-genotype. Similar results were obtained on the basis of comparison of E2 sequences with one exception. Strain 5 grouped with BVDV1f strains based on 5' UTR comparison but was grouped with the novel sub-genotype based on E2 sequence comparison. In conclusion, the results of phylogenetic analyses indicate that diverse strains were found in this study and this point should be considered in the design of diagnostic and preventive measures to be used in Turkey.