Bovine viral diarrhoea: Pathogenesis and diagnosis (original) (raw)
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Veterinary Microbiology, 1999
To detect Bovine Virus Diarrhoea Virus (BVDV)-specific antibodies in cattle serum, plasma and bulk milk, a simple, reliable and rapid blocking ELISA ("Ceditest") has been developed using two monoclonal antibodies ("WB112" and "WB103") directed to different highly conserved epitopes on the non-structural peptide NS3 of pestiviruses. The test can be performed at high reproducibility using undiluted samples. In testing 1000 field serum samples, the ELISA showed a specificity and a sensitivity relative to the virus neutralization test of 99% and 98%, respectively. The blocking ELISA is able to detect specific antibodies in serum obtained 12 days after an acute infection and in serum of vaccinated and challenged animals. A frequency distribution diagram, obtained by testing almost 1800 random Dutch field serum samples, showed a clear separation between a negative population (maximum frequency of the % inhibition at À5%) and a positive population (maximum frequency of the % inhibition at 95%). Based on these data, the prevalence of seropositive animals was 65% (95% confidence interval: 63%±67%). By exchanging plasma-and bulk milk samples between two laboratories (The Netherlands and Denmark), a good overall agreement was found between results obtained with the Ceditest and those obtained with the Danish blocking ELISA as used in the Danish BVDV eradication programme. The results indicate that BVDV infections can reliably be diagnosed by the Ceditest ELISA and that the test is suitable for use in large scale screening and eradication programmes. # . 0378-1135/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 8 -1 1 3 5 ( 9 8 ) 0 0 2 6 5 -X
Virological and molecular studies of Bovine Viral Diarrhea virus
Bovine Viral Diarrhea Virus infection is widespread in cattle worldwide, causing important economic losses. Pathogenesis of the disease caused by BVDV is complex, as each BVDV strain has two biotypes, non-cytopathic (ncp) and cytopathic (cp). It can cause a persistent latent infection and immune suppression if animals are infected with an ncp biotype during early gestation, followed by a subsequent infection of the cp biotype. In this study, a total of 154 samples (28 issue samples , 63 buffy coats and 63 serum samples ), were collected from calves (2-12 months old ), suffering from respiratory manifestations, recumbency, anorexia and abdominal respiration , as well as from closely contact apparently healthy calves, from El-Sharkia and El-kalubia governorates. The results of BVDV detection using Immuofluroescent antibody technique (FAT) in the tissue samples and buffy coates revealed diffuse or granular intracytoplasmic fluorescence in infected cells with a number of positive samples were (6 and 20) & (10 and 16) respectively while detection of BVD antigen using Immunocapture ELISA kit (I-C ELISA), in buffy coates revealed a number of positive samples were (30 &19) respectively. Nested- Reverse transcptase polymerase chain reaction (nRT-PCR) confirmation of BVDV in the tissue samples {Lung, spleen, kidney and lymph nods}, idicate the presence of BVDV type 1 in Six samples {(3) lungs, (2) kidney and (1) lymph node} with specific band at 360 bp. The results of BVDV antibodies detection in the serum samples using virus neutralization test (VNT), revealed a number of positive samples (26 & 15) respectively with a total number of (41), while its detection using competitive ELISA, revealed a number of positive samples (33 &21) respectively with a total number of (54) , The relationship between the VNT positive samples in the serum samples and the reactivity in (ELISA) was recorded.
Considerations for bovine viral diarrhea (BVD) testing
The Bovine Practitioner
Available diagnostic tests for bovine viral diarrhea virus (BVDV) and the persistently infected (PI) BVDV carrier state are reviewed and presented in table format. The test of choice will depend on the age of animal being tested, whether the animal is alive or dead and whether the veterinarian is only interested in identifying PI animals or if transiently infected (TI) animals are also of interest. Economic considerations, including the likelihood of finding a PI animal in a given population (expected prevalence), cost of disease due to the presence of a PI animal and the economic risk of selling a PI animal to a customer, will impact the choice of BVD testing strategy. Potential advantages and disadvantages for the available laboratory tests and suggested tests for particular situations are presented in table format.
Detection of bovine viral diarrhea virus (BVDV) in seropositive cattle
Preventive veterinary …, 2005
Detection of bovine virus diarrhoea virus (BVDV) in one vaccinated beef cattle and three nonvaccinated dairy herds was investigated on peripheral blood leukocytes (PBL) with or without previous treatment followed by a capture ELISA (cELISA). Using the combination of PHA and polycation treatment, PBL from 229 seropositive cattle were studied and could be classified in four different states of BVDV infection. Lysed PBL from four animals were directly positive in cELISA (Category I), PBL of 17 animals were positive after PHA stimulation (Category II), 15 animals were positive only after PHA stimulation plus polycation treatment (Category III), while virus could not be detected in 193 seropositive cattle. Wild-type BVDV strains were isolated by co-culture on polycation-treated MDBK cells from 11 of these seropositive animals. BVDV antibodies of these same animals were able to neutralize their own virus, indicating that virus persists in PBL in spite of strain-specific antibodies. No apparent change of leukocyte subpopulations could be detected in any category of virus-positive animals. Thus, BVDV may be present in the PBL of some cattle, even in the presence of a specific active immune response. #
Veterinary Microbiology, 2002
Retrospective analyses of cases from which bovine viral diarrhea virus (BVDV) was isolated from 1980 to 2000 were conducted. These cases originated from the northwestern US and included both beef and dairy cattle. The results indicated that there was a shift in diseases associated with BVDV infection and in the animal age at onset of disease. Comparative results from the 1980 data indicated a low fetal infection rate (<5%), followed by steady increases of clinical cases and peaking at 6 months (30%). By 2000, the shift of BVDV cases was noticeable and indicated a biphasic occurrence of disease. The ®rst phase was fetal infections, which increased to >25%, followed by a second phase at 6 months (>35%). Phylogenetic analysis was conducted on selected isolates from the time period 1998±2000 (n 54). There were representative viral isolates from the two genotypes (BVDV1 and BVDV2), as well as subgenotypes, BVDV1a and BVDV1b. The types were further correlated with the clinical manifestation, which were reported as mucosal disease, persistently infected (PI)-poor doer, and abortion-open cows. The results indicated that BVDV were distributed throughout the clinical spectrum of disease, with BVDV2 representing the greatest frequency of isolation, and the greatest association with abortion-open cows. When the BVDV genotypes and subgenotypes were categorized into early (<100 days gestation) versus late (>100 days gestation) fetal infections, there was an inverse relationship noted. It was observed that BVDV1a was associated least with early infection (14%) and most with late infections (86%). BVDV1b was intermediate, followed by BVDV2, which was associated more with early infections (45%) and less with late infections (55%) when compared with BVDV1a and BVDV1b.
Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc, 2016
Bovine viral diarrhea virus 1 (BVDV-1) is associated with mild or subclinical infections, whereas BVDV-2 is frequently implicated in outbreaks of severe thrombocytopenia and acute fatal disease. In the present study, the carcass of a beef breed cow and tissue samples of a beef calf were received for laboratory diagnosis. Both animals exhibited severe clinical signs compatible with thrombocytopenia or hemorrhagic syndrome. Direct fluorescent antibody test (DFAT) failed to detect BVDV antigen in the tissue specimens of both cases. However, immunohistochemistry (IHC) revealed the presence of BVDV antigen in oral and esophageal mucosa and Peyer patches of the beef breed cow. Real-time reverse transcription polymerase chain reaction (real-time RT-PCR) detected BVDV-2 in selected tissues of both animals. Subsequently, BVDV was isolated from both cases and subjected to genetic and serologic characterizations. Mutations in the 5'-untranslated genomic region (5'-UTR) primer and probe...
Veterinary Sciences, 2015
Colostrum contains substantially higher concentrations of immunoglobulins compared to serum, which may help to improve the utility of diagnostic tests. The aim of this study was to determine the diagnostic value of colostrum antibody concentrations in identifying Bovine Viral Diarrhoea Virus (BVDV) PI (persistently infected) calf carrying beef heifers following an experimental infection. Colostrum was collected within 12 hours of parturition and tested in undiluted, 1:5, 1:10, 1:100, 1:200, and 1:500 dilutions using an enzyme-linked immunosorbent assay (ELISA) for BVDV antibody. Cows were determined to be carrying a PI calf based on positive quantitative Real Time-Polymerase Chain Reaction and antigen ELISA result on pre-colostral serum and ear notch samples collected from their calf. The median ELISA sample-to-positive (S/P) ratio for colostrum collected from heifers that carried a PI calf were significantly higher than the median ELISA S/P ratio for colostrum collected from heifers that did not carry a PI calf at dilutions of 1:100, 1:200, and 1:500. This study provides further evidence for increased antigenic stimulation in utero by the BVDV viraemic PI calf, which can also be identified with 100% diagnostic sensitivity when using 1:500 dilution colostrum.