Bovine Virus Research Articles

Development of a One-Step Multiplex Real-Time PCR Assay for the Detection of Viral Pathogens Associated With the Bovine Respiratory Disease Complex.

Bovine respiratory disease complex (BRDC) occurs widely in cattle farms. The main viral pathogens include bovine viral diarrhea virus (BVDV), Bovine herpesvirus 1 (BoHV-1), bovine parainfluenza virus type 3 (BPIV3), and bovine respiratory syncytial virus (BRSV), and the newly emerged influenza D virus (IDV). In this study, we have developed a one-step multiplex real-time Polymerase Chain Reaction (PCR) capable of simultaneously detecting these five viral pathogens causing BRDC. The established assay could specifically detect targeted viruses without cross-reaction with others. The detection limit was ~10 copies/reaction for single real-time PCR and 100 copies/ reaction for multiplex real-time PCR assay. A total of 213 nasal samples from cattle with signs of respiratory tract disease were then collected for performance evaluation of the established platform, proving that the method has good specificity and sensitivity. The surveillance data suggested that BVDV and BoHV-1 infections are the dominant cause of BRDC in the herd, whereas the detection rate of IDV, BIPV3, and BRSV is relatively lower. In summary, the established assay provides technical support for rapid clinical detection of BRDC associated viral pathogens to guide the formulation of BRDC prevention and control measures.

Preparation of bovine viral diarrhea disease virus 1 virus-like particles and evaluation of its immunogenicity in a guinea pig model

In order to obtain virus-like particles (VLPs) for prevention of bovine viral diarrhea virus 1 (BVDV-1), the C-Erns-E1-E2 region was cloned into a pFastBacDaul vector for generating the recombinant Bacmid-BVDV-1 in DH10Bac Escherichia coli. The recombinant baculovirus Baculo-BVDV-1 was produced by transfecting the Sf9 cells with Bacmid-BVDV-1. The expressed protein and the assembled VLPs were determined by immunofluorescence, Western blotting and electron microscopy. Guinea pigs were immunized with inactivated VLPs coupled with the Montanide ISA-201 adjuvant. The immunogenicity of VLPs was evaluated by monitoring the humoral immune response with neutralizing antibody titer determination, as well as by analyzing the cell-mediated immune response with lymphocyte proliferation assay. The protective efficacy of VLPs was evaluated by challenging with 106 TCID50 virulent BVDV-1 strain AV69. The results showed that the recombinant Baculo-BVDV-1 efficiently expressed BVDV structural protein and form VLPs in infected Sf9 cells. The immunization of guinea pigs with VLPs resulted in a high titer (1:144) of neutralizing antibody, indicating an activated cellular immunity. Significantly lower viral RNA in the blood of the post-challenged immunized guinea pigs was observed. The successful preparation of BVDV VLPs with insect cell expression system and the observation of the associated immunogenicity may facilitate further development of a VLPs-based vaccine against BVD.

Detection of a New Variant in Outbreak of Bovine Ephemeral Fever in Turkey, 2020

Background: In this study, partial nucleotide sequence analysis of the G gene was performed for the molecular characterization of the virus that caused the bovine ephemeral fever virus (BEFV) epidemic in Turkey in 2020. Phylogenetic analysis of these nucleotide sequences was performed with the virus nucleotide sequences of the epidemics seen in 2008 and 2012. These sequences were announced in GenBank. Phylogenetic analysis of these nucleotide sequences was performed with the virus nucleotide sequences of the epidemics seen in 2008 and 2012. Methods: The study was conducted in dairy cattle holdings located in Diyarbakır Sur, Çınar and Dicle regions in South-eastern Turkey in August-November 2020. The number of animals in the holdings consisted of 750 (n=750), 150 (n=150) and 200 (n=200) cattle, respectively. Result: Severe respiratory symptoms and high mortality in the affected animals were notable symptoms. As a result of the phylogenetic analysis, it was determined that the virus that caused the epidemic in Turkey in 2020 was formed by a new variant in the Turkey-2 group, which was similar to the Indian isolates, unlike the Turkey-1 group, which was close to the Middle East variants in 2008 and 2012 isolates.

Bovine ephemeral fever virus

This datasheet on bovine ephemeral fever virus covers Identity, Overview, Distribution, Hosts/Species Affected, Vectors & Intermediate Hosts, Further Information.

Molecular characterization and phylogenetic analysis of bovine ephemeral fever viruses in Khuzestan province of Iran in 2018 and 2020

BackgroundBovine ephemeral fever (BEF) is an arthropod-borne viral disease caused by the BEF virus (BEFV). This single-stranded RNA virus that affects cattle and water buffalo is endemic in tropical and subtropical regions including Iran. While BEF is a major disease of cattle in Iran, information regarding its agent, molecular characterization, and circulating viruses are highly limited. The current study aimed to, firstly, determine the genetic and antigenic characteristics of BEFV strains in Khuzestan province in Southwest of Iran in 2018 and 2020 and, secondly, to compare them with strains obtained from other areas.ResultsBy phylogenetic analysis based on the Glycoprotein gene, BEFV strains were divided into four clusters of Middle East, East Asia, South Africa, and Australia; in which the 2018 and 2020 Iranian BEFV strains were grouped in the Middle East cluster with the Turkish, Indian, and Israeli strains. Depending on the chronology and geographical area, the outbreaks of Turkey (2020), Iran (2018 and 2020), and India (2018 and 2019) are proposed to be related. These BEFVs had the highest identity matrix and the lowest evolutionary distance among the studied strains. Multiple sequence alignment of G1, G2, and G3 antigenic sites showed that these neutralizing epitopes are highly conserved among the strains of the Middle East cluster; however, the strains previously identified in Iran differed in three amino acids placed in G1 and G2 epitopes.ConclusionThe findings revealed that BEFVs circulating in the Middle East are closely related phylogenetically and geographically. They also have similar antigenic structures; therefore, developing a vaccine based on these strains can be effective for controlling BEF in the Middle East.

Dairy producer satisfaction and knowledge transfer with the veterinary-administered risk assessment and management plan in a voluntary Johne's disease control program

The Atlantic Johne's Disease Initiative (AJDI) aims to control Mycobacterium avium ssp. paratuberculosis infection by using veterinary-administered risk assessments to identify high-risk management practices and prompt changes in management behavior. Objectives for this study were to measure producer satisfaction with the veterinary-administered risk assessment and management plan (RAMP) process in a voluntary Johne's disease (JD) control program, compare RAMP-specific satisfaction results based on herd JD status, and measure knowledge transfer from certified veterinarians to producers during the RAMP. A satisfaction questionnaire was adapted to the RAMP process in the AJDI to measure producer satisfaction. The questionnaire included 9 RAMP-specific producer satisfaction items, 1 global RAMP satisfaction item, and 16 questions to assess producer knowledge and knowledge translation about JD, bovine viral diarrhea (BVD), and bovine leukosis virus (BLV) during the RAMP (BVD and BLV used for comparison purposes). A total of 133 dairy producers in the AJDI (79.6% response rate) completed the questionnaire by telephone. The RAMP-specific satisfaction was high among the AJDI producers surveyed, and these results were not found to differ based on herd JD status. The lowest satisfaction scores and the highest number of "unable to assess" responses were for the item relating to cost. Factors that contributed to RAMP-specific producer satisfaction were not identified from the demographic and herd information available in this study. The knowledge scores indicated moderate knowledge about JD and fair knowledge about BVD and BLV. Evidence of knowledge translation from the RAMP was mixed in this study. Bovine viral diarrhea knowledge scores were not found to differ based on whether or not the certified veterinarian discussed BVD during the preceding RAMP, but BLV knowledge scores were higher among dairy producers that discussed BLV during the preceding RAMP. Strengths and gaps in producer knowledge about these 3 infectious diseases were identified. By using this producer questionnaire, interventions aimed at improving the content, delivery, and satisfaction of RAMP in JD control programs, such as the AJDI, can be developed.

Efficacy of oleandrin and PBI-05204 against bovine viruses of importance to commercial cattle health.

BackgroundBovine viral diarrhea virus (BVDV), bovine respiratory syncytial virus (BRSV). and bovine coronavirus (BCV) threaten the productivity of cattle worldwide. Development of therapeutics that can control the spread of these viruses is an unmet need. The present research was designed to explore the in vitro antiviral activity of the Nerium oleander derived cardiac glycoside oleandrin and a defined N. oleander plant extract (PBI-05204) containing oleandrin.MethodsMadin Darby Bovine Kidney (MDBK) cells, Bovine Turbinate (BT) cells, and Human Rectal Tumor-18 (HRT-18) cells were used as in vitro culture systems for BVDV, BRSV and BCV, respectively. Cytotoxicity was established using serial dilutions of oleandrin or PBI-05204. Noncytotoxic concentrations of each drug were used either prior to or at 12 h and 24 h following virus exposure to corresponding viruses. Infectious virus titers were determined following each treatment.ResultsBoth oleandrin as well as PBI-05204 demonstrated strong antiviral activity against BVDV, BRSV, and BCV, in a dose-dependent manner, when added prior to or following infection of host cells. Determination of viral loads by PCR demonstrated a concentration dependent decline in virus replication. Importantly, the relative ability of virus produced from treated cultures to infect new host cells was reduced by as much as 10,000-fold at noncytotoxic concentrations of oleandrin or PBI-05204.ConclusionsThe research demonstrates the potency of oleandrin and PBI-05204 to inhibit infectivity of three important enveloped bovine viruses in vitro. These data showing non-toxic concentrations of oleandrin inhibiting infectivity of three bovine viruses support further investigation of in vivo antiviral efficacy.

Seroprevalence and associated factors of viral agents of the bovine respiratory disease complex in buffaloes of Colombia

ABSTRACT: The bovine respiratory disease complex causes sizable losses for livestock producers. Its presentation involves the interaction among multiple viral and bacterial pathogens. Viral agents include: bovine viral diarrhea virus (BVDV), bovine alphaherpesvírus 1 (BoHV-1), bovine parainfluenza virus (bPI3v) and bovine respiratory syncytial virus (BRSV); so far, these viruses have been little studied in the buffalo population. This study is aimed to assess the presence of these viruses in buffalo populations of the department of Córdoba, Colombia. A transversal study was conducted upon assessment of 37 farms and 861 buffaloes. Seroprevalence in animals were as follows: 21.7% (BVDV), 51.5% (BoHV-1), 73.6% (bPI3v) and 58.9% (BSRV), while seroprevalence in farms stood at: 94.6% (BVDV), 100% (BoHV-1), 100% (bPI3v) and 100% (BSRV). Conversely, the multiple seropositivity in buffaloes or past coinfection of viral agents amounted to 23.3% for a single virus, 31.8% for two viruses, 29.4% for three viruses and 7.1% for four viruses; only 8.4% of buffaloes were seronegative for four viruses. This is the first regional epidemiological study in the buffalo populations of Colombia and the results showed viral circulation and multiple seropositivity in animals; in addition, the high prevalence found pose a concerning epidemiological threat.

Identification of Cytotoxic T lymphocyte (CTL) Epitope and design of an immunogenic multi-epitope of Bovine Ephemeral Fever Virus (BEFV) Glycoprotein G for Vaccine Development

Bovine ephemeral fever (BEF), a vector-borne disease of cattle and water buffalo, is enzootic in tropical and subtropical zones of Asia, Australia, and Africa. Since cytotoxic T lymphocytes (CTL) responses may play a key role in the control of bovine ephemeral fever virus (BEFV) infection, it is important to identify and characterize the CTL target epitopes of BEFV antigens. The current study has been designed to identify and characterize the potential CTL epitopes using the Immuno-informatics tools, and it helped find the potent vaccine candidates against BEF. Antigenicity, toxicity, allergenicity, and immunogenicity testing of predicted CTL epitopes was done. Total four CTL epitopes for BEFV G protein, have been identified as potential epitopes. Prediction of the 3D structure of multi-epitope (final structure) was performed using I-TASSER server. Model 1 was selected as the best model with C-Score: −3.71. The modeled G protein structure and multi-epitope structure were validated by the Ramachandran plots Prosa and Verify 3D server. Epitopic regions of 3D protein structure were identified by Chimera UCSF software. Physicochemical properties of the Multi epitope were evaluated using ProtParam server. This is the first report of CTL epitope in the G protein of BEFV. In this manner, they would play an important role in evoking the immune response as well as vaccine development. However, in vitro and in vivo experimental studies are required for suggested epitopes verification. The multi-epitope was designed from regions of the G protein sequence that lacked mutation and genomic diversity. Therefore, it can be introduced as a protein vaccine from all strains of BEFV as a vaccine candidate for design.

Retrospective study of poxviruses diagnosed in cattle from Goiás State, Brazil (2010-2018)

ABSTRACT: A retrospective study of poxvirus infections diagnosed in cattle from Goiás state (GO), Brazil, from 2010 to 2018, was performed. All cases have been investigated by the GO Official Veterinary Service (Agrodefesa), from which technical forms and protocols of veterinary diagnosis laboratories were reviewed. In most cases, samples of oral or cutaneous tissues and/or swabs were submitted for virological diagnosis by polymerase chain reaction (PCR) and/or virus isolation. Thirty seven outbreaks/cases of vesicular disease were notified in cattle of 25 counties; in 33 cases the animals presented lesions clinically compatible with poxviruses. The etiology of 25 out of 33 outbreaks/cases was confirmed as poxviruses by PCR and/or viral isolation: 13 as bovine vaccinia virus (VACV), six as pseudocowpox virus (PCPV), five as bovine papular stomatitis virus (BPSV) and one coinfection (VACV and an Orf virus-like parapoxvirus). The laboratory confirmed that cases occurred mainly in dairy cattle (19/25) and during the dry season (22/25). In adult cattle, gross changes were observed mainly in the teats and udder and included vesicles, ulcers, crusts, papules and scars and varied of type, severity and affected region, depending on the poxvirus species. In calves, the main lesions were ulcers in the mouth and muzzle. Zoonotic lesions compatible with poxvirus infections were observed for all diagnosed poxviruses, affecting especially the hands of milkers and other farm workers. Our data demonstrate the sanitary and economic relevance of these diseases and the wide circulation of different poxviruses in cattle from GO.

Possibility of mechanical transmission of parapoxvirus by houseflies (Musca domestica) on cattle and sheep farms.

Parapoxvirus (PPV) causes papular stomatitis and contagious pustular dermatitis in ruminants worldwide. The virus is generally transmitted through close contact with skin lesions containing PPV in infected animals and indirectly through PPV-contaminated materials. PPV-infected animals frequently do not show clinical signs and the route of PPV transmission is sometimes unclear. In this study, the possibility of mechanical transmission of PPV by houseflies (Musca domestica) was investigated using polymerase chain reaction (PCR) gene surveillance. Samples were collected from cattle, sheep, barn environments, direct wash solution of the body surface of houseflies, and indirect wash solution of the body surface and feces of the flies. Bovine papular stomatitis virus, pseudocowpox virus, and orf virus were detected in the oral cavity and body surface of cattle and sheep without clinical signs of PPV infection or barn environments; PPV was considered to have been retained on the farm. PPVs were also detected in the direct wash solution of the body surface of houseflies, and the indirect wash solution of the body surface and feces of the flies. The viral sequence determined from the indirect wash solution of the body surface and feces of the flies was identical to that determined from the body surface of cattle and barns. These results suggested that houseflies may mechanically transmit PPV to both cattle and sheep.

Pathological and Molecular Studies on Diagnosis of Infectious Bovine Abortions

Bovine abortions have a multifactorial aetiology involving bacterial, viral, fungal and protozoan agents. In the present study, gross pathological, histopathological and polymerase chain reaction (PCR) technique(s) have been applied for diagnosis of infectious abortion in bovine. Histopathology was used as a reference technique to support the confirmation by PCR. Aborted bovine fetuses (n=31) of various gestational age and placenta (n=11) of aborted dam were or infectious diseases screened, which includes Neospora caninum, Brucella abortus, To/oplasma gondii and Infectious bovine rhinotracheitis virus. Gross lesions observed in aborted foetuses were serosanguineous fluid in the thoracic cavity, congestion of cerebrum, heart, liver and lungs. Lesions such as cerebral congestion with non-suppurative encephalitis, perivascular cuffing and Purkinje cell layer degeneration of brain, exfoliation of placental chorionic epithelium along with severe lymphomonocytic cell infiltrations were observed histopathologically. Eosinophilic intranuclear inclusions were observed in two placental tissues using routine H&E staining and special staining for inclusion bodies. PCR showed amplification of gene for the existence of N. caninum (1/31), Brucella (7/31) and BHV-1 (2/31) in the stomach content of aborted foetuses.

Detection of Bovine Ephemeral Fever Virus (BEFV) in Three Egyptian Governorates During Summer of 2019.

Detection of Bovine Ephemeral Fever Virus (BEFV) in Three Egyptian Governorates During Summer of 2019.

Pseudocowpox virus, a novel vector to enhance the therapeutic efficacy of antitumor vaccination.

ObjectiveAntitumor viral vaccines, and more particularly poxviral vaccines, represent an active field for clinical development and translational research. To improve the efficacy and treatment outcome, new viral vectors are sought, with emphasis on their abilities to stimulate innate immunity, to display tumor antigens and to induce a specific T‐cell response.MethodsWe screened for a new poxviral backbone with improved innate and adaptive immune stimulation using IFN‐α secretion levels in infected PBMC cultures as selection criteria. Assessment of virus effectiveness was made in vitro and in vivo.ResultsThe bovine pseudocowpox virus (PCPV) stood out among several poxviruses for its ability to induce significant secretion of IFN‐α. PCPV produced efficient activation of human monocytes and dendritic cells, degranulation of NK cells and reversed MDSC‐induced T‐cell suppression, without being offensive to activated T cells. A PCPV‐based vaccine, encoding the HPV16 E7 protein (PCPV‐E7), stimulated strong antigen‐specific T‐cell responses in TC1 tumor‐bearing mice. Complete regression of tumors was obtained in a CD8+ T‐cell‐dependent manner after intratumoral injection of PCPV‐E7, followed by intravenous injection of the cancer vaccine MVA‐E7. PCPV also proved active when injected repeatedly intratumorally in MC38 tumor‐bearing mice, generating tumor‐specific T‐cell responses without encoding a specific MC38 antigen. From a translational perspective, we demonstrated that PCPV‐E7 effectively stimulated IFN‐γ production by T cells from tumor‐draining lymph nodes of HPV+‐infected cancer patients.ConclusionWe propose PCPV as a viral vector suitable for vaccination in the field of personalised cancer vaccines, in particular for heterologous prime‐boost regimens.

INTERACTION OF TIO2 NANOPARTICLES AND PROTEINS OF AN IMMUNE COMPLEX IN PHOTOLUMINESCENCE BASED BIOSENSOR

Interaction between nanostructured semiconductor thin layers and immune complex based proteins is a fundamental issue of the formation of nanobiointerface in the various biosensors, in particular, optical biosensors. In this work, the main aspects of the interaction between photoluminescent TiO2 nanoparticles and Bovine leucosis virus (BLV) protein gp51, used as a model protein, during the formation of photoluminescence based immunosensor have been discussed. The antigens of gp51 were immobilized on the surface of a nanostructured TiO2 thin film formed on the glass substrates. As a result, an increase of the photoluminescence (PL) signal intensity and PL peak shift from 517 nm to 499 nm were observed. An incubation of TiO2/gp51 structure in a solution containing anti-gp51 antibodies resulted in the backward PL peak shift from 499 nm to 516 nm and decrease of the PL intensity. The main reason of the changes in the PL spectra (i.e. PL maxima shifts and PL intensity variations) as a result of BLV protein gp51 adsorption on the surface TiO2 thin film is an electrostatic interaction between negatively charged surface of TiO2 and positively charged atoms and groups provided by the adsorbed gp51 protein due to the presence of partial uncompensated charges within the proteins.

Parenteral Antioxidant Supplementation at Birth Improves the Response to Intranasal Vaccination in Newborn Dairy Calves.

Newborn calves experience oxidative stress throughout the first month of their life, which is known to decrease lymphocyte functions relevant to vaccine responsiveness. Thus, this study aimed to determine the extent to which parenteral antioxidant supplementation given at birth improves the response to an intranasal viral vaccine in the first month of life of newborn dairy calves. For this, 21 calves were randomly assigned at birth to one of two commercially available antioxidant micronutrient supplements or a placebo group receiving 0.9% sterile saline (n = 7/group). Serum and nasal secretion samples were collected before administration of treatments and an intranasal vaccine against respiratory viruses (bovine herpesvirus type 1, bovine syncytial respiratory virus, and parainfluenza 3), and once weekly for the first four weeks of age. Systemic redox balance was determined in serum. Immunoglobulin A specific for bovine herpesvirus 1 and bovine syncytial respiratory virus was quantified in nasal secretions as a proxy to intranasal vaccine responsiveness. Our results showed that parenteral administration of antioxidants at birth improved calves’ redox balance. Additionally, calves receiving antioxidant supplementation had higher concentrations of immunoglobulin A in their nasal secretions than calves in the control group. Thus, we conclude that supplementation of calves with antioxidants at birth could be a practical strategy to improve intranasal vaccine response. Future larger studies should evaluate the extent to which this increased mucosal response to intranasal vaccination could result in decreased calf morbidity and mortality.

A double deletion prevents replication of the pestivirus bovine viral diarrhea virus in the placenta of pregnant heifers.

In contrast to wild type bovine viral diarhea virus (BVDV) specific double deletion mutants are not able to establish persistent infection upon infection of a pregnant heifer. Our data shows that this finding results from a defect in transfer of the virus from the mother animal to the fetus. Pregnant heifers were inoculated with such a double deletion mutant or the parental wild type virus and slaughtered pairwise on days 6, 9, 10 and 13 post infection. Viral RNA was detected via qRT-PCR and RNAscope analyses in maternal tissues for both viruses from day 6 p.i. on. However, the double deletion mutant was not detected in placenta and was only found in samples from animals infected with the wild type virus. Similarly, high levels of wild type viral RNA were present in fetal tissues whereas the genome of the double deletion mutant was not detected supporting the hypothesis of a specific inhibition of mutant virus replication in the placenta. We compared the induction of gene expression upon infection of placenta derived cell lines with wild type and mutant virus via gene array analysis. Genes important for the innate immune response were strongly upregulated by the mutant virus compared to the wild type in caruncle epithelial cells that establish the cell layer on the maternal side at the maternal–fetal interface in the placenta. Also, trophoblasts which can be found on the fetal side of the interface showed significant induction of gene expression upon infection with the mutant virus although with lower complexity. Growth curves recorded in both cell lines revealed a general reduction of virus replication in caruncular epithelial cells compared to the trophoblasts. Compared to the wild type virus this effect was dramtic for the mutant virus that reached only a TCID50 of 1.0 at 72 hours post infection.

Co-circulation of a Novel Dromedary Camel Parainfluenza Virus 3 and Middle East Respiratory Syndrome Coronavirus in a Dromedary Herd With Respiratory Tract Infections.

Since the emergence of Middle East Respiratory Syndrome (MERS) in 2012, there have been a surge in the discovery and evolutionary studies of viruses in dromedaries. Here, we investigated a herd of nine dromedary calves from Umm Al Quwain, the United Arab Emirates that developed respiratory signs. Viral culture of the nasal swabs from the nine calves on Vero cells showed two different types of cytopathic effects (CPEs), suggesting the presence of two different viruses. Three samples showed typical CPEs of Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV) in Vero cells, which was confirmed by partial RdRp gene sequencing. Complete genome sequencing of the three MERS-CoV strains showed that they belonged to clade B3, most closely related to another dromedary MERS-CoV isolate previously detected in Dubai. They also showed evidence of recombination between lineages B4 and B5 in ORF1ab. Another three samples showed non-typical CPEs of MERS-CoV with cell rounding, progressive degeneration, and detachment. Electron microscopy revealed spherical viral particles with peplomers and diameter of about 170nm. High-throughput sequencing and metagenomic analysis showed that the genome organization (3'-N-P-M-F-HN-L-5') was typical of paramyxovirus. They possessed typical genome features similar to other viruses of the genus Respirovirus, including a conserved motif 323FAPGNYALSYAM336 in the N protein, RNA editing sites 5'-717AAAAAAGGG725-3', and 5'-1038AGAAGAAAGAAAGG1051-3' (mRNA sense) in the P gene with multiple polypeptides coding capacity, a nuclear localization signal sequence 245KVGRMYSVEYCKQKIEK261 in the M protein, a conserved sialic acid binding motif 252NRKSCS257 in the HN protein, conserved lengths of the leader (55nt) and trailer (51nt) sequences, total coding percentages (92.6–93.4%), gene-start (AGGANNAAAG), gene-end (NANNANNAAAAA), and trinucleotide intergenic sequences (CTT, mRNA sense). Phylogenetic analysis of their complete genomes showed that they were most closely related to bovine parainfluenza virus 3 (PIV3) genotype C strains. In the phylogenetic tree constructed using the complete L protein, the branch length between dromedary camel PIV3 (DcPIV3) and the nearest node is 0.04, which is >0.03, the definition used for species demarcation in the family Paramyxoviridae. Therefore, we show that DcPIV3 is a novel species of the genus Respirovirus that co-circulated with MERS-CoV in a dromedary herd in the Middle East.

Effect of feeding single-dam or pooled colostrum on maternally derived immunity in dairy calves

The role of colostrum management in providing adequate immunological protection to neonatal calves has been widely investigated, and thresholds for colostrum quality, as well as optimum volume and timing for colostrum feeding have been established. However, limited information is available on the effect of colostrum source (single dam or pooled) on passive immunity, as well as subsequent antibody survival in the calf. This study aimed to assess the effect of feeding single-dam colostrum (own and other dam) or pooled colostrum on transfer of passive immunity, and also investigate the rate of depletion of disease-specific antibodies among dairy calves. In total, 320 cows and 119 dairy heifer calves were enrolled in the study. Calves were blood-sampled immediately after birth and received either own-dam, other-dam, or pooled colostrum. Calves were blood-sampled at 24 h to assess serum IgG concentrations and at monthly intervals thereafter to document disease-specific antibody survival. Mean colostrum IgG concentration was higher for other-dam treatment group, whereas own-dam and pooled treatments were similar. For all treatment groups, the mean IgG concentration was >80 mg/mL, exceeding the quality threshold of 50 mg/mL. Mean calf serum IgG concentration was lower for calves fed pooled colostrum compared with those that received colostrum from a single cow. There was a negative association with 24-h serum IgG and calf birth bodyweight; calves <30 kg at birth had the highest 24-h serum IgG concentration. Survival of antibodies to bovine viral diarrhea, Salmonella infection, leptospirosis, bovine parainfluenza 3 virus, bovine respiratory syncytical virus, rotavirus, and coronavirus was not associated with colostrum source; however, antibodies to infectious bovine rhinotracheitis had a greater period of survival among calves fed own-dam colostrum. We found that feeding single-dam colostrum can thus improve calf immunity through increased serum IgG levels and antibody survival rates. Furthermore, we hypothesize that immune exclusion may occur with pooled colostrum; therefore, providing pooled colostrum may still be a good practice as long as it can be ensured that enough antibodies are absorbed into the blood stream to deal with pathogens calves may encounter because different dams may have antibodies against different strains of viruses and bacteria, yielding cross protection.

A lateral flow dipstick combined with reverse transcription recombinase polymerase amplification for rapid and visual detection of the BVDV and BPIV3

Bovine respiratory disease complex (BRDC) is a serious disease affecting feedlot cattle in China and likely other places worldwide. Bovine viral diarrhea virus (BVDV) and bovine parainfluenza virus type 3 (BPIV3) are principally responsible for causing BRDC, and are a major strain to the industrial economy. Eradication of these viruses/disease requires swift viral identification and treatment. Hence, this study established a fast and easy procedure of BVDV and BPIV3 identification that employs reverse transcription recombinase polymerase amplification (RT-RPA) and lateral flow dipstick (LFD), and uses primers and lateral flow (LF) probe targeting the 5′-UTR gene of BVDV and phosphoprotein P gene of BPIV3, respectively. Our assay was able to successfully amplify BVDV and BPIV3 RNA within 25 min at 35 °C using RT-RPA, with products visible on the LFD within 5 min at room temperature (RT). The lowest detection limits were 50 RNA molecules for BVDV and 34 RNA molecules for BPIV3 per reaction. We also demonstrated that the established dual RT-RPA LFD assay was precise and targeted, harboring excellent potential to become an onsite molecular diagnostic tool in the detection of BVDV and BPIV3. This method can detect BVDV (Pestivirus A, B) and BPIV3, and exhibit no cross-reaction with other viruses like the classical swine fever virus (CSFV) and infectious bovine rhinotracheitis virus (IBRV). The assay performance was further assessed with clinical samples, and demonstrated good performance in comparison to real-time RT-PCR (RT-qPCR). Moreover, the RT-RPA LFD assay was comparitively rapid and required minimal training.