Three cases of alloimmune mediated pancytopenia in calves resembling bovine neonatal pancytopenia

Background Between 2007 and 2011 several thousands of calves died from bovine neonatal pancytopenia (BNP), a bleeding syndrome triggered by vaccine induced alloantibodies from the dams. Following withdrawal of the involved bovine viral diarrhoea virus (BVDv) vaccine, the incidence of this condition rapidly decreased, with no reported cases in the last 5 years. Here, we report a recent immune-mediated pancytopenia in three calves from two different suckler herds, clinically indistinguishable from BNP. Case presentation Three Belgian Blue suckler calves from two different farms, aged around two weeks, showed multiple bleedings disseminated on the skin and petechiae and ecchymoses on the mucosae. Blood examination confirmed anaemia, leukopenia and thrombocytopenia. BVDv infection was excluded. Despite blood transfusion and cortisone therapy, all three animals died. Necropsy and histology confirmed bone marrow depletion. Binding of IgG from the dams on leukocytes of the calves was demonstrated by flow cytometry. Two calves, originating from the same farm, received colostrum from the same dam. None of the calves were given colostrum replacers or colostrum supplements. No link with the BNP causing BVDv vaccine could be evidenced. However, dams had been vaccinated against bovine herpesvirus 1, parainfluenza-3 virus, bovine respiratory syncytial virus and bluetongue virus serotype 8. Conclusions Alloimmune mediated pancytopenia was evidenced in three animals, clinically and pathologically indistinguishable from BNP. Whether this disease is again vaccine mediated remains to be determined.

Seroprevalence and risk factors of Neospora caninum and Bovine Viral Diarrhoea Virus in smallholder dairy cattle in Kenya

Little is known of the risk factors associated with occurrence of Neospora caninum and Bovine Viral Diarrhoea Virus (BVDV) infection in Kenya. This cross-sectional study hypothesized that there are significant biosecurity measures associated with N. caninum and BVDV infections on smallholder dairy farms in Kenya that could be adopted to reduce seroprevalence and impacts. From 158 randomly selected farms in Meru County, Kenya, 470 serum samples were collected from dairy cattle (over six months of age and unvaccinated for these two pathogens). Sera were analyzed for antibodies to N. caninum and antibodies and antigens to BVDV. Data on risk factors were obtained through face-to-face interviews with the farmers. Multivariable logistic regression models were used to identify significant risk factors associated with seropositivity for the pathogens. The apparent seroprevalence of N. caninum, BVDV antibody, BVDV antigen, and co-infection with N. caninum and BVDV antibody and/or antigen were 35.1%, 47.1%, 36.2% and 18.5%, respectively. Risk factors associated with N. caninum antibody included: introducing milking cows into the farm, lending of cattle between farms, farm dogs having access to bovine aborted fetuses, and dogs whelping in the farm compound, with an interaction between the last two variables. BVDV antigen was associated with cattle having contact with pigs, and an interaction between cattle age and whether farms introduced new calves onto farms, and cattle age and whether visiting dairy farmers have access to the cow shed. Cows had higher odds of having BVDV antibodies compared to heifers. Factors associated with co-infection included cow parity, direct contact between dairy cattle, dogs and goats, and introducing new milking cows into the farms. Antibody and antigen results may be partly a function of classical swine fever virus or border disease virus interactions. Farmer education on these biosecurity measures is recommended, along with introduction of BVDV vaccination.

BVDFree England data analysis: descriptive analysis of national bovine viral diarrhoea test data in England.

Background: Bovine viral diarrhoea virus (BVDV) causes substantial economic losses to cattle herds; however, control and eradication can be achieved by identifying and removing persistently infected cattle. Each UK nation has separate control programmes. The English scheme, BVDFree, started in 2016 and is voluntary. Methods: We analysed the test results submitted to BVDFree from 5,847 herds from 2016 to 2020. Results: In 2020, 13.5% of beef breeder herds and 20.0% of dairy herds had at least one positive test result. Though lower than in previous years, there was no clear trend in the proportion of positive tests over time. In antigen testing herds, 1.5% of tests from antigen positive herds were positive, which was 0.4% of tests from all antigen testing herds. Dairy herds and larger herds were more likely to join BVDFree and dairy herds were also more likely to antigen test than beef breeder herds. Larger herds, herds that used individual antigen testing and herds that had BVD positive test results were more likely to continue submitting tests to BVDFree. Conclusions: The findings provide a benchmark for the status of BVD control in England; continued analysis of test results will be important to assess progress towards eradication.

The Use of Oncolytic Viruses in the Treatment of Multiple Myeloma

Multiple myeloma accounts for 1% of all new cancers worldwide. It is the second most common haematological malignancy and has a low five-year survival rate (53.2%). Myeloma remains an incurable disease and is caused by the growth of malignant plasma cells in the bone marrow. Current anti-myeloma therapies (conventional chemotherapies, immunomodulatory drugs i.e., thalidomide and its’ analogues, proteasome inhibitors, monoclonal antibodies, and radiotherapy) initially substantially debulk tumour burden, but after a period of remission ‘plateau phase’ disease invariably relapses due to tumour recrudescence from foci of minimal residual disease (MRD) and accumulating drug resistance. Therefore, there is a compelling clinical need for the development of novel treatment regimens to target MRD and effectively eliminate all remaining tumour cells. This review will discuss the potential use of oncolytic virus (OV) therapies in the treatment of myeloma. Specifically, it will focus on preclinical studies using DNA viruses (adenovirus (Ad), vaccinia virus (VV), myxoma virus (MYXV), and herpes simplex virus (HSV)), RNA viruses (reovirus (reo), coxsackie virus, measles virus (MV) and bovine viral diarrhoea virus (BVDV), and vesicular stomatitis virus (VSV)), and on four types of viruses (VV, reo, MV-NIS and VSV-IFNβ-NIS) that have been assessed clinically in a small number of myeloma patients.

A novel NS3/4A protease dependent cleavage site within pestiviral NS2

Pestiviruses like bovine viral diarrhoea virus (BVDV) and classical swine fever virus (CSFV) belong to the family Flaviviridae. A special feature of the Flaviviridae is the importance of nonstructural (NS) proteins for both genome replication and virion morphogenesis. The NS2-3-4A region and its regulated processing by the NS2 autoprotease and the NS3/4A protease plays a central role in the pestiviral life cycle. We report the identification and characterization of a novel internal cleavage in BVDV NS2, which is mediated by the NS3/4A protease. Further mapping using the NS2 of BVDV-1 strain NCP7 showed that cleavage occurs between L188 and G189. This cleavage site represents a novel sequence motif recognized by the NS3/4A protease and is conserved between the pestivirus species A, B and D. Inhibition of this internal NS2 cleavage by mutating the cleavage site did not cause obvious effects on RNA replication or virion morphogenesis in cultured cell lines. Accordingly, this novel internal NS2 cleavage adds an additional layer to the already complex polyprotein processing of Pestiviruses and might further extend the repertoires of the multifunctional NS2. However, unravelling of the functional relevance of this novel processing event in NS2, therefore, awaits future in vivo studies.

Benefit of Bovine Viral Diarrhoea (BVD) Eradication in Cattle on Pestivirus Seroprevalence in Sheep

Bovine viral diarrhoea virus (BVDV) and Border disease virus (BDV) are closely related pestiviruses of cattle and sheep, respectively. Both viruses may be transmitted between either species, but control programs are restricted to BVDV in cattle. In 2008, a program to eradicate bovine viral diarrhoea (BVD) in cattle was started in Switzerland. As vaccination is prohibited, the cattle population is now widely naïve to pestivirus infections. In a recent study, we determined that nearly 10% of cattle are positive for antibodies to BDV. Here, we show that despite this regular transmission of BDV from small ruminants to cattle, we could only identify 25 cattle that were persistently infected with BDV during the last 12 years of the eradication program. In addition, by determining the BVDV and BDV seroprevalence in sheep in Central Switzerland before and after the start of the eradication, we provide evidence that BVDV is transmitted from cattle to sheep, and that the BVDV seroprevalence in sheep significantly decreased after its eradication in cattle. While BDV remains endemic in sheep, the population thus profited at least partially from BVD eradication in cattle. Importantly, on a national level, BVD eradication does not appear to be generally derailed by the presence of pestiviruses in sheep. However, with every single virus-positive cow, it is necessary to consider small ruminants as a potential source of infection, resulting in costly but essential investigations in the final stages of the eradication program.

Eradication of Bovine Viral Diarrhoea (BVD) in Cattle in Switzerland: Lessons Taught by the Complex Biology of the Virus

Bovine viral diarrhoea virus (BVDV) and related ruminant pestiviruses occur worldwide and cause considerable economic losses in livestock and severely impair animal welfare. Switzerland started a national mandatory control programme in 2008 aiming to eradicate BVD from the Swiss cattle population. The peculiar biology of pestiviruses with the birth of persistently infected (PI) animals upon in utero infection in addition to transient infection of naïve animals requires vertical and horizontal transmission to be taken into account. Initially, every animal was tested for PI within the first year, followed by testing for the presence of virus in all newborn calves for the next four years. Prevalence of calves being born PI thus diminished substantially from around 1.4% to <0.02%, which enabled broad testing for the virus to be abandoned and switching to economically more favourable serological surveillance with vaccination being prohibited. By the end of 2020, more than 99.5% of all cattle farms in Switzerland were free of BVDV but eliminating the last remaining PI animals turned out to be a tougher nut to crack. In this review, we describe the Swiss BVD eradication scheme and the hurdles that were encountered and still remain during the implementation of the programme. The main challenge is to rapidly identify the source of infection in case of a positive result during antibody surveillance, and to efficiently protect the cattle population from re-infection, particularly in light of the endemic presence of the related pestivirus border disease virus (BDV) in sheep. As a consequence of these measures, complete eradication will (hopefully) soon be achieved, and the final step will then be the continuous documentation of freedom of disease.

Is the end in sight for bovine viral diarrhoea virus, or is it just a mirage?

Bovine viral diarrhoea (BVD) is an infectious disease that significantly affects the health, welfare and productivity of cattle. Elimination of bovine viral diarrhoea virus (BVDV) is technically feasible. There are mandatory BVDV elimination programmes in Ireland, Northern Ireland, Isle of Man and Scotland. There are voluntary BVD programmes in England and Wales. The main focus of BVDV elimination programmes is the identification and slaughter of cattle persistently infected with BVDV (PIs). PI animals shed large amounts of virus in all excretions and secretions and are the main source of infection for other cattle. BVDV elimination can only succeed within a realistic timescale if PIs are removed quickly enough to minimise the risk of infection resulting in the generation of further PI animals. Maintaining stakeholder cohesion, commitment and engagement is also key in a BVD programme. All cattle farms need to be free of BVDV to eliminate the risk of infection and voluntary programmes are unlikely to reach all farms. The mandatory programme in Ireland started in 2013 and it is aiming to seek a declaration of freedom under the EU Animal Health Law in 2023. The other programmes are at various stages along the pathway to BVDV elimination. The stated intention of the cattle industry in the UK is elimination of BVDV by 2031. This will be a stretch target, particularly in England, but should be possible if the approach is science-based and the delivery programmes have the committed support of farmers and veterinary surgeons.

Infertility in dairy cows – Possible bacterial and viral causes

In this research uterine swab and biopsy samples were collected from 40 infertile dairy cows kept at five dairy cattle farms in Hungary. Samples were tested for bacteria including Coxiella burnetii chlamydiae, Mycoplasma and Ureaplasma, and for the viruses Bovine herpesvirus 1 (BoHV-1) and Bovine viral diarrhoea virus (BVDV). Chlamydiaceae DNA was detected by real-time PCR in 22/40 (55%) samples. Coxiella burnetii DNA was detected in 3/40 (7.5%) cases by real-time PCR. Mycoplasma and Ureaplasma DNA was found in 2/40 (5%) and 4/40 (10%) cows, respectively. BVD and BoHV-1 DNA was not detected in any samples. Escherichia coli as a recognised uterine pathogen was found in two cases. The following potential uterine pathogens were found: Bacillus licheniformis (one case), non- haemolytic streptococci (five cases), Histophilus somni (two cases) and Candida krusei (two cases). Blood samples were collected at same time as swab samples from all 40 cows, and their examination for C. burnetii antibodies by ELISA revealed seropositivity in 26/40 cows (65%). Histological examination of the uterine biopsy samples showed the presence of mild lympho-histiocytic infiltration in the mucosain 22 cases (59%). Moderatelympho-histiocytic infiltration of the endometrium was evident in 13 cases (35%), while in two cases (6%) severe inflammatory cell infiltration of the endometrium with lympho-histiocytes and neutrophil granulocytes was found. Although no statistical correlation could be demonstrated between the severity of histological lesions of the endometrium and the uterine pathogenicity of the bacteria (P = 0.8555), endometritis of a certain severity grade and/or a recognised or potential uterine pathogen were found in all samples. The latter may play a role in the development of infertility either collectively or independently.

The Principles of the Voluntary Programme for the Control and Elimination of Bovine Viral Diarrhoea Virus (BVDV) From Infected Herds in Slovenia

In Slovenia, the control of bovine viral diarrhoea virus (BVDV) infections started in 1994. Since 2014, a voluntary programme has been running according to the national rules that prescribe the conditions for recognising, acquiring, and maintaining a BVDV-free status for an individual herd. The principle is based on periodical laboratory testing and preventive measures that need to be strictly implemented in a herd. Between 2014 and 2020, a total of 348 herds were included in BVDV antibody testing, and 25.0% of tested herds were detected to be BVDV antibody positive. To recognise the BVDV-free status of the herd, the breeder should provide two consecutive tests with intervals of at least 6 months in all animals in the age from 7 to 13 months, with negative results for BVDV antibodies in ELISA. The BVDV-free status of the herd can be maintained by implementing preventive measures and can be renewed each year with one laboratory test in the age group of animals from 7 to 13 months for antibodies in ELISA. During the 7 years of the voluntary programme, 236 herds were included in the detection of BVDV in individual herds by real-time RT-PCR method and the elimination of positive animals from herds. In 71 (31.3%) herds, at least one BVDV-positive animal was detected, with the identification of a total of 267 persistently infected (PI) animals, representing an average of 2.9% of tested animals. The cost of testing for an average herd, recognised as BVDV-negative, and maintaining its BVDV-free status within the implemented voluntary programme, was €97.64/year, while for the average positive herd, the laboratory costs for elimination of BVDV were €189.59/year. Only limited progress towards eradication at the national level has been achieved in Slovenia since 2014.