|Bolin, Steven - Steve|
Submitted to: Journal of Veterinary Diagnostic Investigation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/22/1999
Publication Date: N/A
Citation: N/A Interpretive Summary: Bovine viral diarrhea (BVD) virus is a common viral pathogen that infects cattle of all ages. Disease induced by BVD virus is multisystemic, which means infected cattle may show signs of respiratory disease, reproductive disease, or enteric disease. Economic losses attributable to BVD virus are considerable in the U.S. and many other parts of the world. Based on phenotypic and genetic characteristics, BVD viruses can be classified as noncytopathic or cytopathic in infected cell cultures and as genotype 1 or genotype 2. Hence, BVD viruses may be segregated into at least four groups. Classical laboratory methods for determination of the group to which a BVD virus belongs are time consuming and expensive. A rapid nucleic acid-based diagnostic test was developed that allows detection and classification of BVD viruses. The test uses polymerase chain reaction (PCR) amplification of viral RNA to first detect virus, then a second PCR test is done to type the virus. The PCR test was used on clinical specimens, laboratory isolated viruses, and vaccine viruses to correctly identify and type BVD viruses. The beneficiaries of this research are veterinary diagnostic laboratories, veterinarians, vaccine manufacturers, and cattle producers. Accurate, rapid diagnostic tests aid control of disease in cattle and helped to ensure a wholesome food supply for the public.
Technical Abstract: One hundred and three bovine samples submitted to the Oklahoma Animal Disease Diagnostic Laboratory (OADDL) were positive for bovine viral diarrhea virus (BVDV). The samples were typed by a nested reverse transcription-polymerase chain reaction (PCR) for BVDV genotypes. These BVDV samples included supernatants from virus isolation (79), serums (17), and buffy coats (7). The biotype, cytopathic (CP) or noncytopathic (NCP), was determined by cell culture virus isolation. Twenty-eight of 103 samples were submitted for herd screening for BVDV, 32 from OADDL necropsy cases, and 43 from live cattle with varied clinical conditions. There were two samples containing two bands indicating presence of both BVDV types 1 and 2. Of the 105 BVDV samples, there 26 type 1 CP strains (24.8%), 38 type 1 NCP strains (36.2%), 10 type 2 CP strains (9.5%), and 31 type 2 NCP strains (29.5%). From the 105 BVDV isolates, NCP biotypes were isolated more frequently, 69 (65.7%), than CP biotypes, 36 (34.3%), and type 1 genotypes were more frequently isolated, 64 (61.0%) than type 2 genotypes, 41 (39.0%). The NCP strains were more common than CP in herd screening samples. Cattle with respiratory disease history at time of sampling had more NCP than CP biotypes and more type 1 than type 2 genotypes. Of the necropsy cases, there were more type 1 than type 2 genotypes for the respiratory cases with fibrinous pneumonia, more type 1 than type 2 genotypes in cattle with enteritis/colitis without systemic lesions, and more CP than NCP biotypes in cattle with enteritis/colitis with systemic lesions. There were no CP biotypes isolated from serum samples.