Bovine Viral Diarrhea Virus Antibodies Research Articles

Prevalence of bovine viral diarrhea virus antibodies and risk factors in dairy cattle in Gondar city, Northwest Ethiopia

Bovine viral diarrhea (BVD) is a disease that affects cattle and other ruminants worldwide and causes considerable economic losses. A cross-sectional study was carried out between December 2017 and July 2018 with the aim to estimate the prevalence of Bovine Viral Diarrhea virus (BVDV) antibodies and to identify potential risk factors associated with the occurrence of the disease in dairy cattle in peri-urban areas of Gondar city, Northwest Ethiopia. A total of 339 serum samples obtained from randomly selected dairy cattle aged 6 months and older were assayed using a BVDV antibody competitive-Enzyme Linked Immunosorbent Assay (c-ELISA) kit. Descriptive statistics were used to estimate antibody prevalence of BVDV at animal and herd-level and logistic regression was used to identify potential risk factors. The study findings showed that the animal-level antibody prevalence of BVDV in the study area was 26.84 % (95 % CI: 22.1 %–31.6 %) and the herd-level seroprevalence was 68.3 % (95 % CI: 56.2 %–80.4 %). Logistic regression model demonstrated that age >2 years (OR = 4.75, 95 % CI: 2.20−10.26), herd size >11 (OR = 7.28, 95 % CI: 2.50−21.22), and poor farm hygiene (OR = 3.69, 95 % CI: 1.94−7.02), are potential risk factors associated with BVDV infection (P < 0.05). However, sex, faecal consistency and housing system were not associated with BVDV serostatus. The animal- and herd-level seroprevalence reports in Northwest Ethiopia can serve as a baseline finding for future BVD epidemiological investigations and to inform future control programs in the study region.

Detection of Pestivirus A (bovine viral diarrhea virus 1) in free-living wild boars in Brazil.

Bovine viral diarrhea virus (BVDV) is a major pathogen in cattle herds. Considering the epidemiological importance of pestiviruses and the process of wild boar invasion in Brazil, this study aimed to investigate the presence of BVDV in free-living boars. Forty-nine free-living wild boars were collected by exotic wildlife controller agents in 2017 and 2018. The presence of BVDV antibodies was evaluated in 42 serum samples using the virus neutralization test, and the detection of BVDV RNA was performed from the 5'UTR genomic region by RT-PCR assay in 49 lung tissue samples followed by sequencing of amplicons. BVDV neutralizing antibodies in serum were not identified in any of the evaluated samples. However, 3/49 (6.12%) lung samples were positive for BVDV RNA and classified one as BVDV-1a and two as 1d subgenotype. This report identified BVDV RNA in free-living wild boars and these results should be considered in BVDV control programs, especially in extensive beef cattle rearing systems.

Infection with Bovine Viral Diarrhea Virus in Cattle in Southern Papua, Indonesia

The aim of this preliminary study was to determine the prevalence of Bovine Viral Diarrhea Virus (BVDV) and its association with reproductive problems in cattle in Timika, Southern Papua, Indonesia, an emerging area for beef production. Serum from 77 beef cattle was collected from four villages and tested, using both antibody and antigen ELISA kits for BVDV. Data of the villages of origin, age, breed, sex and the number of parities of the cattle were collected. The pregnancy status of the cattle was determined by rectal examination. Results showed that the prevalence of BVDV antibody in individual cattle in Timika was 11.7% (CI: 6.1 – 20.0%), while at the farm level the antibody prevalence was 18.4% (CI: 8.9 – 33.7%).). Seropositivity for BVDV increased with age (P=0.02), from 0% (CI: 0 – 37.2%) in less than two-years old to 28.6% (CI: 11.3 – 55.0%) in cattle older than eight years of age. BVDV antibody was 2.9 times more prevalent in non-pregnant cows than in antibody negative cows (CI: 1.02 - 8.14, P=0.04). BVD antigen was not detected in the present study. This study reported for the first time, evidence of infection with BVDV in cattle in Papua and indicated that BVDV infection may be associated with infertility.

Determination of presence and prevalence of Bovine Viral Diarrhea Virus infection in cattle herds in Bingol province

Persistant bovine viral diarrhoea virus (BVDV) is an important cultivate disease in cattle breeding. Persistent infected (PI) animals are the main virus carrier within and between flocks at virus transmission. Consequently the presence of persistent ınfected (PI) animals should be determined and removed from the herd. In this study, a total of 105 blood samples collected from the cattle were brought to the Bingol University Faculty of Veterinary Medicine around Bingol for different purposes. The presence of BVDV antigen and antibodies in these blood samples was investigated by enzyme immunoassay (ELISA) test. The presence of BVDV antigens in12/105 ( 11.42% ) and antibodies in 40/105 (38.09%) were detected of the samples. On the other hand In the tree cattle BVDV antibody was not detected but only the antigen was detected. This states that 3/105 (2.85%) animals had persistent BVDV infection. These animals are constantly sick and they spread out the virus. In this article, the presence and the incidence of persistent BVDV in the region was demonstrated 3/105 (2.85%) by this study. It has emphasized the need to control of the disease in the region for rational cattle breeding in the province. Eradication offers the supplementary advantage of developed herd health; however, it also composes a favorable cattle population that needs to be screened by strict biosecurity.

Detección de herpesvirus bovino 4 (BoHV-4) en rodeos lecheros de Uruguay

Bovine herpesvirus type 4 (BoHV-4) is a gammaherpesvirus worldwide distributed. It has been isolated in healthy and unhealthy animals with respiratory infections, vulvovaginitis, mastitis, abortions and endometritis. The persistent infection of BoHV-4 happens in monocytic cells and tissues that are part of peripherical and/or central nervous system. The reduced reproductive efficiency and the low index of procreation are the main problems in the Uruguayan breeding cattle. Reproductive tract infections include two main viruses identified in the country, infectious bovine rhinotracheitis (IBR) virus (bovine herpesvirus type 1, BoHV-1) and bovine viral diarrhea virus (BVDV). In some countries of the region have been evidenced the presence of BoHV-4 and its possible relationship with reproductive problems. Thus, the main aim of this study is to detect the presence of BoHV-4 in Uruguayan dairy herds. Commercial ELISA were used to detected BoHV-4, BoHV-1 and BVDV antibodies. PCR was used to detect the presence of BoHV-4 DNA and the products were confirmed by Sanger sequencing. Were used 597 samples of Holstein cattle from Florida, Durazno and Tacuarembo provinces. A total of 195 (32.7%) were positive to BoHV-4, 285 (47.7%) to BoHV-1 and 564 (94.4%) to BVDV antibodies. To BoHV-4 DNA, 13 of 17 samples were positives. The alignment to phylogenetic analysis showed a high degree of similarity (97.2%) among Uruguayan and worldwide strains. This is the first diagnosis of the presence of BoHV-4 in Uruguay. Future studies must evaluate the dissemination of the virus in the bovine population and the likely impact it has in the dairy healthy and national milk production.

Immune response to bovine viral diarrhea virus (BVDV) vaccines detecting antibodies to BVDV subtypes 1a, 1b, 2a, and 2c

Bovine viral diarrhea virus (BVDV) represents a major cattle disease with multiple forms including fetal infections resulting in persistently infected (PI) cattle. The objectives of this study were to investigate the immune response to six vaccines, five modified live viral (MLV) and one killed vaccine containing BVDV immunogens as measured by antibodies to BVDV1a, BVDV1b, BVDV2a, and BVDV2c. The predominant BVDV subgenotype in the U.S. is BVDV1b compared to BVDV1a and BVDV2a. There are MLV and killed BVDV vaccines containing BVDV1a and BVDV2a marketed in the U.S. A prior study evaluated immune response to vaccination with BVDV1a and BVDV2a inducing virus neutralizing antibody titers. BVDV1b titers 128 or higher at time of exposure to BVDV1b PI cattle protected heifers against fetal infection. Calves received two doses and postweaning serums were collected and assayed for BVDV antibodies. Antibody titers were expressed as geometric mean averages. Percentages were expressed as proportions of animals within three antibody levels, including targeted level 128 or greater. There were statistical differences among vaccines in each study, particularly to BVDV1a, BVDV1b, and BVDV2a. MLV vaccines containing Singer strain induced higher levels to BVDV1a and BVDV1b than NADL vaccine in all three studies. Two vaccines, both MLV, Vaccine 1 and Vaccine 6 containing Singer strain induced higher proportion of 128 or higher BVDV1b titers than vaccine with NADL. Antibody levels to BVDV2a and BVDV2c were dependent on BVDV2a vaccine strain. This study indicates strain in BVDV vaccines reflects differences in immune response to different BVDV subgenotypes, particularly BVDV1b and BVDV2c.

Attenuated porcine-derived type 2 bovine viral diarrhea virus as vector stably expressing viral gene

Infectious bovine viral diarrhea virus (BVDV) cDNA clones have been used for the expression of classical swine fever virus (CSFV) genes for immune prevention and control. However, can it be used for the expression of an allogenetic fragment? To answer this question, a BVDV chimeric virus expressing the spike (S) antigen fragment of porcine epidemic diarrhea virus (PEDV) was constructed. Antigen S499-602 was inserted into pig-derived BVDV-2 infectious cDNA clone pASH28 in tandem by overlapping PCR, located between the seventh and eighth amino acids at the N-terminus of the capsid (C) protein of BVDV. Indirect immunofluorescence assay confirmed that the chimeric virus vASH-dS312 containing double S499-602 sequences was successfully assembled, which could react with the monoclonal antibody (MAb) against BVDV E2 and PEDV S proteins. Further western blot analysis confirmed that the exogenous S499-602 double protein could be stably expressed. Next, the chimeric virus vASH-dS312 was administered to BALB/C mice either orally or by intramuscular injection. The immunized mice were healthy and showed no signs of toxicity. IgG against BVDV and PEDV antibodies could be detected in the mice administered vASH-dS312 by intramuscular injection, which had neutralization activity against BVDV and PEDV. Thus, this study reported a new insertion site in the BVDV infectious cDNA clone that could successfully express an allogenetic antigen.

Serological evidence for exposure to bovine viral diarrhoea virus in sheep co-grazed with beef cattle in New Zealand

ABSTRACTAims: To determine whether sheep that co-grazed with cattle that were suspected to be positive for bovine viral diarrhoea (BVD) virus had serological evidence of exposure to the virus.Methods: Eighteen commercial farms that routinely co-grazed cattle and sheep in the same paddocks were recruited through purposive sampling. The recruiting veterinarians identified nine farms with cattle herds that were known or highly suspected to be positive for BVD and nine farms that were considered to be free of BVD. Blood samples were taken from 15 ewes aged 1 year on each farm and samples were submitted to a commercial diagnostic laboratory to test for antibodies against pestiviruses using an ELISA. All samples that were positive were then tested using a virus neutralisation test (VNT)for antibodies against BVD virus.Results: Of the 270 blood samples, 17 were positive for pestivirus antibodies by ELISA and these originated from two farms that were known or suspected to have BVD virus-positive cattle. None of the samples from the nine flocks co-grazed with cattle herds that were known or suspected to be BVD virus-negative were positive for pestivirus antibodies. Within the two positive farms, 2/15 samples from the first farm and 15/15 samples from the second farm were antibody-positive. When the 17 positive blood samples were submitted for VNT, all 15 samples from the second farm tested positive for BVD virus antibodies with the highest titre being 1:512.Conclusions and clinical relevance: In this small sample of New Zealand sheep and beef farms with suspected BVD infection in cattle, there was evidence of pestivirus exposure in co-grazed sheep. Although we were unable to confirm the origin of the exposure in these sheep, these findings highlight that farmers who are trying to eradicate BVD from their cattle should be mindful that the infection may also be circulating in sheep, and both populations should be considered a possible risk to each other for generating transient and persistent infections. Further work is needed to estimate the true prevalence of New Zealand sheep flocks that are affected by BVD and the associated economic impacts.

Seroprevalence of canine neosporosis and bovine viral diarrhoea in dairy cattle in selected regions of Kenya.

Neospora caninum is the causative agent for canine neosporosis (CN), a disease of potential zoonotic importance causing reproductive losses in cattle while causing neuromuscular disease in dogs. Bovine viral diarrhoea on the other hand is caused by the bovine viral diarrhoea virus (BVDV) and is one of the most important reproductive diseases of cattle worldwide. In Kenya, these infections are of economic importance due to the losses they cause in farms in which they are diagnosed or are subclinical. Such losses include reduced milk production, reduced conception, early embryonic deaths and abortions which lead to reproductive wastage. This study was conducted between April 2017 and July 2018 and determined the seroprevalence of neoporosis and BVD in select dairy herds in Kenya. Kakamega, Nandi and Makueni Counties from where dairy farms were purposively sampled were used. Serum samples were collected from randomly selected dairy animals aged at least 2years in the selected farms and screened for BVDV and CN antibodies. Seroprevalence of N.caninum was 24.1% (n=552) and BVD, 52.3% (n=545) across all the counties. Co-infection where antibodies against the two infective agents were present was in 14.6% (n=541) animals. Chi-square tests of association between prevalence and county were significant for BVD (p=.000) but not for neosporosis (p=.626). Further chi-square tests of association between the two infections were not significant (p=.105) neither were the associations of BVD (p=.575) and neosporosis (p=.626) on pregnancy status. These two diseases are rarely investigated as causes of bovine infertility. Detection of antibodies in the studied dairy herds underpins the need for enhanced surveillance by laboratories and for further studies to understand associated risk factors to formulate effective control strategies in dairy cattle to forestall abortions and production and reproduction losses.

Diagnostic studies of abortion in Danish cattle 2015\u20132017

BackgroundAbortion is a major source of economic losses in cattle breeding. Abortion occurs due to a wide range of causes, but infections are the most frequently diagnosed. However, establishing an aetiological diagnosis remains challenging due to the large variety of bacteria, protozoa, viruses, and fungi that have been associated with abortion in cattle. Economic restraints limit the range of diagnostic methods available for routine diagnostics, and decomposition of the conceptus or lack of proper fetal and/or maternal samples further restrict the diagnostic success. In this study, we report recent diagnostic findings from bovine abortions in Denmark, a country that has a large dairy sector and is free from most infectious agents causing epizootic abortion in cattle. The aims of the study were: (i) to identify infectious causes of bovine abortion in Denmark, (ii) to categorise the diagnostic findings based on the level of diagnostic certainty, and (iii) to assess the diagnostic rate. Due to economic restraints, only a limited panel of routine diagnostic methods were available. Placentas and/or fetuses from mid- to late-term abortions and stillbirths (n = 162) were submitted to the Danish National Veterinary Institute between January 2015 and June 2017. The aborted materials were examined macroscopically, histologically, and by bacterial culture. Maternal blood samples were tested for bovine viral diarrhoea virus (BVDV) antibodies.ResultsThe likely aetiology of the abortion was diagnosed in 52 cases, resulting in a diagnostic rate of 33%. The most common cause was protozoal infection (19%) followed by infection with Trueperella pyogenes (3%), Staphylococcus aureus (2%), and non-haemolytic Escherichia coli (2%). Lesions in fetuses with a protozoal infection were consistent with neosporosis. In many cases (38%), inflammatory changes were found in the placenta and/or fetal organs but no specific aetiology was identified. Neither infection with Brucella spp. nor maternal BVDV antibodies were detected. The majority of submitting herds (92%) were each represented by fewer than three abortion cases over the study period.ConclusionsProtozoal infection, most likely neosporosis, was the most commonly diagnosed cause of abortion and the only one associated with potential epizootic abortion events. Despite using a reduced number of diagnostic methods in comparison to other abortion studies, the diagnostic rate of this study was within the range reported in an earlier Danish study, as well as in recent international studies. The low number of submitted cases per herd and the sparse anamnestic information provided at submission hampered conclusions on the potential epizootic character of the abortion events in question.

Screening of persistently infected cattle with bovine viral diarrhea virus on dairy farms by using milk tanker and bulk tank milk samples for viral RNA and viral-specific antibody detection.

The objective of this study was to provide a screening scheme of persistently infected (PI) cattle on dairy herds by combining reverse-transcription polymerase chain reaction (RT-PCR) to detect bovine viral diarrhea virus (BVDV) in milk tanker samples and commercial enzyme-linked immunosorbent assay to detect BVDV antibodies in bulk tank milk. We conducted a pilot survey and regional survey targeting all dairy farms in Ibaraki Prefecture by using milk tanker and bulk tank milk samples to screen PI cattle. Farms with positive samples underwent a follow-up test to identify PI cattle. In the pilot study, all virus-positive samples in bulk tank milk were included in the positive milk tanker samples. The RT-PCR assay successfully detected BVDV at dilutions of 1:1,600 by using two PI cows’ milk. In the regional survey, 5 of 79 milk tanker samples were virus-positive. The virus was detected in three PI lactating cows and one PI calf on three farms. Antibody screening using bulk tank milk samples revealed 15 of 363 samples were positive, and 12 of 348 farms were BVDV antibody-positive. Follow-up tests on one farm identified three PI calves. Thus, eight PI cattle on five farms were identified in this study. In conclusion, combining BVDV detection using milk tanker samples and antibody detection using bulk tank milk is a feasible and economical method to efficiently screen PI cattle and confirm the PI-free status among dairy herds.

20 Antibody response, lesions, and performance do not differ between injection site (ischiorectal fossa or neck) after multivalent modified-live virus vaccination in Jersey steers

Abstract The study objective was to explore the feasibility of an alternative injection site, ischiorectal fossa (IRF), for modified-live virus (MLV) vaccination in Jersey steers. We hypothesized administration of MLV in the IRF would not cause injection site lesions and result in similar antibody response against bovine viral diarrhea virus (BVDV) compared to the neck. Jersey steers (n = 28; BW=517 ± 116 kg) were stratified by a previously assigned growth implant treatment and day-35 BVDV antibody titer and randomly assigned to 1 of 2 treatments with injection treatment equivalently represented in each of 2 pens. Treatments consisted of: 1) 2 mL MLV vaccine administered s.c. in the neck (NECK); or 2) 2 mL MLV vaccine administered s.c. in the IRF. Blood was collected on days -35, 0, 35, 70, and 105 to determine BVDV-specific antibody titers using the virus neutralization assay and BW was recorded on the same days to determine gain performance. Steers were harvested on day 106 and examined for lesions respective to injection site. Antibody titers and performance variables were statistically analyzed via a mixed model with animal as the experimental unit. Concentration of BVDV antibody increased (P = 0.05) with time, but there was no treatment difference (P = 0.94) or treatment × day interaction (P = 0.70). There was no treatment difference for BW on any day (P ≥ 0.78). There was also no treatment difference in ADG (P ≥ 0.45). However, there was a period effect, where ADG was reduced markedly (P &amp;lt; 0.0001) for the day 0 to 35 interim period immediately following MLV vaccination compared to day -35 to 0 (0.79 vs. 0.18 kg/d). No injection site lesions were observed during harvest and results from BVDV antibody titers and performance indicate IRF as a potential alternative route of administration for MLV vaccines.

Practices and opinions of New Zealand beef cattle farmers towards bovine viral diarrhoea control in relation to real and perceived herd serological status

ABSTRACTAims: To investigate the seroprevalence of infection with bovine viral diarrhoea (BVD) virus among 75 beef herds and seroconversion in cattle during early pregnancy, and to determine the practices and opinions of farmers towards BVD control and their association with real and perceived herd serological status.Methods: Blood samples were collected before mating in 75 beef herds across New Zealand from 15 unvaccinated heifers that had delivered their first calf that season. Serum samples were tested for BVD antibodies using ELISA individually, and after pooling samples for each farm. Animals that were antibody-negative were retested at either pregnancy diagnosis or weaning. Farmers were asked to complete a detailed survey about herd demographics, BVD testing and vaccination practices, and opinions towards national BVD control.Results: Based on the pooled serum antibody ELISA results, there were 28/75 (37%) negative herds, 15/75 (20%) suspect herds, and 32/75 (43%) positive herds. Of 1,117 animals sampled 729 (65.3%) tested negative for BVD virus antibodies; when retested, 47/589 (8.0%) animals from 13/55 (24%) herds had seroconverted. Among 71 famers providing survey responses 11 (15%) believed their herd was infected with BVD, 24 (34%) were unsure and 36 (51%) did not think their herd was infected. Only 19/71 (18%) farmers had performed any BVD testing within the past 5 years and 50/70 (71%) had not vaccinated any cattle for BVD. Support for national BVD eradication programme was strong in 51/71 (56%) respondents, but the biggest challenge to BVD control was considered to be famer compliance. Compared to farmers who did not think their herd was infected, more farmers who thought BVD was present in their herds had previously tested for BVD, would consider testing all replacement calves, and would support establishing a national BVD database; fewer would consider purchasing BVD tested or vaccinated cattle only.Conclusions and clinical relevance: Only 15% of the beef farmers in this study believed their herds were infected with BVD virus and few of them had undertaken BVD screening. Nevertheless many were supportive of implementing a national BVD control programme. It is likely that the lack of farmer awareness around BVD and the failure of farmers to recognise the potential impacts in their herds are hindering progress in controlling the disease in New Zealand. There are opportunities for New Zealand veterinarians to be more proactive in helping beef farmers explore BVD management options.

Exploring the longitudinal dynamics of herd BVD antibody test results using model-based clustering

Determining the Bovine Viral Diarrhoea (BVD) infection status of cattle herds is a challenge for control and eradication schemes. Given the changing dynamics of BVD virus (BVDV) antibody responses in cattle, classifying herds based on longitudinal changes in the results of BVDV antibody tests could offer a novel, complementary approach to categorising herds that is less likely than the present system to result in a herd’s status changing from year to year, as it is more likely to capture the true exposure dynamics of the farms. This paper describes the dynamics of BVDV antibody test values (measured as percentage positivity (PP)) obtained from 15,500 bovines between 2007 and 2010 from thirty nine cattle herds located in Scotland and Northern England. It explores approaches of classifying herds based on trend, magnitude and shape of their antibody PP trajectories and investigates the epidemiological similarities between farms within the same cluster. Gaussian mixture models were used for the magnitude and shape clustering. Epidemiologically meaningful clusters were obtained. Farm cluster membership depends on clustering approach used. Moderate concordance was found between the shape and magnitude clusters. These methods hold potential for application to enhance control efforts for BVD and other infectious livestock diseases.

Evaluation of currently available bovine viral diarrhoea virus (BVDV) and HoBi-like pestivirus (HoBiPeV) specific diagnostic tests in detection of highly divergent HoBiPeVs in cattle

The emergence of novel and divergent HoBi-like pestivirus (HoBiPeV) strains in cattle in Asia recently has raised concerns with regard to their reliable and accurate diagnosis. Hence, the aim of this study was to evaluate currently available BVDV diagnostic tests and HoBiPeV-specific diagnostic tests in detection of genetically divergent strains of HoBiPeV. One strain each of HoBiPeV-c and d were subjected to two BVDV diagnostic RT-PCR tests, one HoBiPeV specific RT-PCR test, three BVDV diagnostic qRT-PCR tests, one HoBiPeV specific qRT-PCR test and two BVDV antigen capture ELISAs. Archived cattle sera (n = 41) from farms with reports of HoBiPeV natural infection were assessed for detection of HoBiPeV antibodies by VNT and two commercial BVD antibody ELISA kits. BVDV diagnostic qRT-PCR tests had better sensitivity than BVDV diagnostic RT-PCR tests, while majority of them except a commercial kit showed a lower sensitivity for HoBiPeV-d strain. The HoBiPeV specific qRT-PCR test was found more sensitive than HoBiPeV specific RT-PCR but both had lower sensitivity for HoBiPeV-d strain, as displayed by primer/probe sequence mismatches. The BVDV Erns antigen ELISA detected both the strains of HoBiPeV, but with a lower sensitivity for HoBiPeV-d strain, whereas BVDV NS3 antigen ELISA failed to detect them even at a high HoBiPeV titre. Compared to VNT, commercial BVDV antibody ELISA showed low to moderate sensitivity in detection of HoBiPeV antibodies, with a failure rate of 31.25% for the whole virus antigen based ELISA and a failure rate of 56.25% for NS3 antibody ELISA. The present study demonstrated new challenges in HoBiPeV diagnosis indicating a need in improvement of both HoBiPeV specific diagnostic RT-PCR and qRT-PCR for better utility in HoBiPeV epidemiology and biological product safety. Although more studies are required, this study reinforces that combined use of BVDV Erns and NS3 antigen ELISA may have some utility in preliminary differentiation between HoBiPeV and BVDV infection in PI cattle. Additionally, we show that the comparative VNT has a better sensitivity in detection of HoBiPeV exposure and there is a need of robust antibody ELISA for reliable detection of antibodies against this emerging bovine pestivirus.

Hydrocephalus Internus and other Neural Malformations, Brachyury in German Holstein Twin Calves

A two-days-old female German Holstein twin calf borned a deformed cranium. The calf was not able to endure and died shortly after the clinical examination and this calf was submitted to necropsy. Pathological-anatomical examination showed multiple malformations including hydrocephalus internus and atrophy of cerebellar hemispheres, hypoplasia of the cerebellum, syringomyelia in the cervical spinal cord and the cranial part of the thoracic spinal cord, hydromyelia in the caudal part of the thoracic spinal cord, scoliosis between the fifth and seventh thoracic vertebra and bilateral keratitis could be associated with a positive result for bovine viral diarrhoea (BVD) virus antibodies. Its male co-twin with brachyury and also dam of the twins were positive for BVD virus antibodies by ELİSA Test. Infection by BVD virus in an early stage of the pregnancy may be assumed to be responsible for the multiple malformations in the female twin and the brachyury of the male co-twin.

Investigation of persistent infection of bovine viral diarrhea virus (BVDV) in Holstein dairy cows.

The aim of this study was to investigate the persistent infection (PI) of bovine viral diarrhea virus (BVDV) along with its coexistence between BVDV antibody titer and BVD virus in blood of Holstein dairy cows. Only large commercial farms (each contained < 1000-3000 unvaccinated cows) were included. There were 11 dairy cattle herds. They included nearly 20,000 dairy cows. Totally, 140 cows, > 3months to almost 10years old, were randomly sampled. Indirect enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect BVDV antibody and virus, respectively. The percent positivity (PP) < 14 and ≥ 14 values are interpreted negative and positive, respectively. Simultaneously, whole blood samples pooled in groups of 10 animals were used for molecular detection of BVDV. The results revealed that 138 (98.56%) out of 140 cows were positive for BVDV antibody, while the BVDV antigen was detected only in 2 (1.42%) cows, which were negative for BVDV antibody and so were considered as persistent infection (PI) cows. They were also retested 3weeks apart. Since the results showed the strong coexistence between seropositivity and BVD virus, in the infected dairy cattle herds, the combination of simple ELISA and pooled whole blood RT-PCR strategy could be an achievable approach to detect PI animals.

Bayesian assessment of two competitive enzyme-linked immunosorbent assays for the detection of bovine viral diarrhoea virus antibodies in bovine sera.

Infections due to bovine viral diarrhoea virus (BVDV) are endemic in most cattleproducing countries throughout the world and bovine viral diarrhoea is considered a transboundary disease. The key elements of a BVDV control programme are vaccination, biosecurity, elimination of persistently infected (PI) animals and surveillance. The aim of this study was to assess the sensitivity (Se) and the specificity (Sp) of two commercial competitive enzyme-linked immunosorbent assays (ELISAs) based on selected immune-dominant BVDV proteins: the non-structural protein NS3 (p80) and the recombinant envelope glycoprotein E0(Erns). Both tests were used on individual serum samples from randomly sampled young bovines in southern Belgium in order to detect specific BVDV antibodies. The Se and Sp were assessed using a Bayesian approach and were estimated, respectively, at 97.2% (with 95% credibility interval [Cr I]: 95.1-99.8) and 98.7%(95% Cr I: 96.6-99.9) for the first test and 95.8% (95% Cr I: 91.1-99.7) and 96.1%(95% Cr I: 95.1-97.7) for the second test. The results obtained with the two tests were not significantly different. In addition, using both ELISAs, the current BVDV exposure among young bovines in southern Belgium was estimated at 23.3% (95%Cr I: 20.6-26.2). Combining virological testing of all newborns to detect PI animals with regular serological testing of young stock using ELISAs is recommended in the surveillance of BVDV.

Bayesian assessment of two competitive enzyme-linked immunosorbent assays for the detection of bovine viral diarrhoea virus antibodies in bovine sera

Infections due to bovine viral diarrhoea virus (BVDV) are endemic in most cattleproducing countries throughout the world and bovine viral diarrhoea is considered a transboundary disease. The key elements of a BVDV control programme are vaccination, biosecurity, elimination of persistently infected (PI) animals and surveillance. The aim of this study was to assess the sensitivity (Se) and the specificity (Sp) of two commercial competitive enzyme-linked immunosorbent assays (ELISAs) based on selected immune-dominant BVDV proteins: the non-structural protein NS3 (p80) and the recombinant envelope glycoprotein E0(Erns). Both tests were used on individual serum samples from randomly sampled young bovines in southern Belgium in order to detect specific BVDV antibodies. The Se and Sp were assessed using a Bayesian approach and were estimated, respectively, at 97.2% (with 95% credibility interval [Cr I]: 95.1–99.8) and 98.7%(95% Cr I: 96.6–99.9) for the first test and 95.8% (95% Cr I: 91.1–99.7) and 96.1%(95% Cr I: 95.1–97.7) for the second test. The results obtained with the two tests were not significantly different. In addition, using both ELISAs, the current BVDV exposure among young bovines in southern Belgium was estimated at 23.3% (95%Cr I: 20.6–26.2). Combining virological testing of all newborns to detect PI animals with regular serological testing of young stock using ELISAs is recommended in the surveillance of BVDV.

Prevalence of bovine viral diarrhea virus in dairy cattle herds in eastern China

Bovine viral diarrhea virus (BVDV) is a worldwide spreading pestivirus affecting cattle and other ruminants; however, there have been few reports on epidemiologic investigation of BVDV in eastern China. In this study, bulk tank milk from 36 herds of dairy cattle in eastern China was submitted to serological investigations, 77.8% of herds was BVDV antibody positive. Individual animal status in two herds was further investigated collecting blood samples, the positive ratio was 49.74% and 24.64%, and the average positive ratio of calves, heifers, and lactating cows was 15.94%, 40.16%, and 41.7%, respectively. Moreover, clinical survey was carried out among 8170 dairy cattle from 36 herds, for diarrhea syndrome, respiratory problems and reproductive failure, and pathogens of all clinical cattle were further investigated. The results showed that BVDV was one of the main pathogen, which infected animals combining with various other viruses. Then, nine BVDV strains were isolated; phylogenetic analysis showed that BVDV subtypes currently circulating in eastern China were BVDV 1a and BVDV 1c. In addition, out of 377 cows tested, the 1.86% detected positive to the BVDV antigen. This study provided the foundation of further study on vaccination and control strategies of BVDV in eastern China.