ELISA For Detection Of Antibodies Research Articles

A bio-safe multiple antigenic peptide (MAP) enzyme-linked immunoassay for the detection of antibodies to infectious bronchitis virus in chickens.

The objective of the study was to develop a bio-safe synthetic peptide ELISA for the detection of antibodies against the infectious bronchitis virus (IBV) using a novel multiple antigenic peptide approach (MAP). After initial ELISA optimization, diagnostic sensitivity (DSn) and specificity (DSp) for the linear peptides were determined using receiver operator curve (ROC) analysis. The peptide IBVP1 showed 90.44% DSn and 88.64% DSp at ROC cut off 22.8% while IBVP2 showed 88.24% DSn and 85.23% DSp at ROC cut off 23.05%. The multimerization of linear peptides to MAP design resulted in the improvement of the diagnostic efficiency up to 94.85% DSn and 92.05% DSp for IBVM1 with 19.95% cut off. A similar improvement in the performance was also observed with 92.65% DSn and 90.91% DSp for IBVM2 at 20.72% cut off. All the peptides were tested for diagnostic specificity and did not show the cross-reactivity with Newcastle disease virus and infectious bursal disease virus positive serum samples. In addition, repeatability testing for all linear and multimeric peptide showed that the coefficient of variation for intra-assay was within the expected limits, ranging from 2.4 to 10.4% and inter-assay coefficient of variation was ranging from 5.56 to 14.3%. In a nutshell, the present study used predicted B cell epitope, the synthetic peptide in linear and multimeric design for IBV antibody detection. The study also highlights peptide antigen with modified scaffold design could be a safe alternative to whole virion-based ELISA for IBV antibody detection.

Establishment of Milk ELISA for Anti-Bovine Leukemia Virus Antibody Detection

Establishment of Milk ELISA for Anti-Bovine Leukemia Virus Antibody Detection

Lipopolysaccharide based indirect ELISA for rapid detection of Pasteurella multocida antibodies in bovines

Lipopolysaccharide based indirect ELISA for rapid detection of Pasteurella multocida antibodies in bovines

Development of a competition ELISA (cELISA) for specific detection of Zika virus antibodies in human sera

Abstract Infections by Zika virus (ZIKV), a member of the Flavivirus genus, can be diagnosed by virus isolation, detection of virus RNA or by serological methods for detecting ZIKV immunoglobulin M antibodies (IgM), a marker of recent infections, and immunoglobulin G antibodies (IgG), a marker of past infections. In some cases, where IgM antibodies may last for longer periods, accurate diagnosis of recent infections is not always possible. Because commercial and non-commercial serological tests are often confounded by cross-reactivity with other Flaviviruses there is a need for simple, ZIKV-specific serological tests. Here, we present the development of a ZIKV-specific ELISA in which cross-reacting antibodies in serum samples are competed and blocked by Dengue virus antigens (DENV). The competed sera are then tested by ELISA on ZIKV and DENV coated wells to enable a calculation of a ZIKV/DENV (Z/D) cutoff ratio. For the development and validation of the ZIKV specific cELISA we have used three groups of sera from Colombia. 49 sera were obtained in 2018 from individuals that have been infected with ZIKV during a 2016 outbreak. The outbreak was in a DENV endemic area. Another group of 19 sera were obtained from a known DENV endemic area with no evidence of any ZIKV infections. The third group of 12 sera were obtained from patients from an area with no known Flavivirus infections and therefore considered as negative for both ZIKV and DENV. A Z/D ratio of 1.5 was determined as the cutoff value for the specific determination of ZIKV positive or negative sera. Our analysis indicated a 85% agreement with the BOB assay, and a 78% agreement with the commercial IgG ELISA test. The estimated specificity and sensitivity for the cELISA were 70% and 82%, respectively.

Seroprevalence of Dengue Viral Infection in Patients Attending To a Tertiary Care Hospital in Kota, South–East Rajasthan, India

Background: Dengue virus (DENV) is the most important cause of mosquito-borne viral disease in humans world-wide. Dengue fever is caused by four serotypes of dengue virus (DENV)-DENV1, DENV2, DENV3 and DENV4 .Infections is transmitted mainly by Aedes aegypti. In India, a dengue virus infection has been frequently encountered in epidemic proportions in several states. Objectives: This study was conducted to report the seroprevalence of Dengue virus infection in South-East Rajasthan. The ultimate goal of this study was to identify Dengue infection in early phase of disease and prevent future complications. Methodology: The present study was conducted in the central laboratory of Govt. Medical College, Kota from period of 1st January 2018 to 31th December 2018 to evaluate the seroprevalence of Dengue virus infection in South-East Rajasthan. Sera were tested by SD dengue IgM antibody capture ELISA for IgM antibody detection as per kit insert. Results: Out of total 16945 serum samples tested, 1064(6.28%) were found positive for dengue virus infection. Of all the patients tested, 12031(71%) were males and 4914(29%) were females. 659(61.94%) positive samples were of male patients and 405(38.06%) positive samples were of female patients. Dengue affected males and females in a ratio of about 1.6:1. Out of the total positive for dengue, Age group mostly affected were 21-30 years, 31-40 years and 11-20 year 38.53%, 27.54% and 18.70% respectively. Seasonal trend showed a gradual increase in dengue positives started from August with a peak in October (30.73%) and November (21.43 %).Conclusion: Dengue is an important emerging disease of the tropical and subtropical regions today. Epidemics of dengue are increasing in frequency. Dengue virus activity is high during monsoon and post monsoon period which coincides with increased vector breeding. This study calls attention to the Dengue infection detected in early phase of disease and prevents morbidity, mortality and future complications. Keywords: Dengue virus, Dengue fever, Mosquito-borne viral disease, Dengue IgM antibody, ELISA. Cite this Article Bhupendra Kumar Mandawat, Preetam Singh Mandawat. Seroprevalence of Dengue Viral Infection in Patients Attending To a Tertiary Care Hospital in Kota, South–East Rajasthan, India. Research & Reviews: A Journal of Microbiology & Virology. 2020; 10(1): 1–9p.

An efficient fiber-based ELISA for detection of antibody against fowl adenovirus serotypes 7 and 8.

An outbreak of inclusion body hepatitis caused by fowl adenovirus serotype 8 (FAdV-8) has caused significant economic losses in the poultry industry worldwide. However, a rapid serology test kit specific to FAdV-8 is not available to date. We developed a fiber-based ELISA using the purified GST-fiber of FAdV-8 as coating antigen to measure antibodies against FAdV-8. Specificity analysis showed that our ELISA could react with sera against FAdV-7, -8a, and -8b, but not with sera against the other pathogens tested. Moreover, detection of positive sera with our ELISA had 83% and 94% agreement with an indirect immunofluorescence assay (IFA) and a commercial ELISA from BioChek, respectively. Our ELISA was also effective in the detection of antibodies against FAdV-8 in sera from both experimentally infected and clinically vaccinated chickens. Our FAdV-8 fiber-based ELISA can be a valuable tool to specifically and sensitively detect antibodies against FAdV-7 and/or -8 in infected or vaccinated chickens.

Horses are susceptible to natural, but resistant to experimental, infection with the liver fluke, Fasciola hepatica

Fasciola hepatica is a common parasite of livestock in Ireland, causing significant economic losses and affecting animal welfare. A previous abattoir study of 200 horses led to an estimated 9.5 % prevalence of infection in horses slaughtered in Ireland. However, the epidemiology and pathogenic significance of this infection in this species is not well-described.The objectives of this study were to determine the susceptibility of horses to oral challenge infection with F. hepatica metacercariae, and to document the course of the infection along with serological and biochemical response.We attempted an experimental infection of horses (n = 10; 9 geldings and 1 mare) with F. hepatica. Four were given 1000 metacercariae, four 500 metacercariae and two were sham-infected. Blood and faecal samples were taken at intervals up to 18 weeks post-infection (wpi). ELISA assays were used to assess sero-conversion in the experimental horses and also in a panel of sera from horses of known fluke status.No flukes were recovered from any of the livers, and neither were any lesions that could be attributed to F. hepatica infection observed. Coproantigen ELISA was negative throughout for all horses. Three antibody detection ELISAs, useful in diagnosing fasciolosis in other species, had limitations as diagnostic aids as determined using a panel of sera from horses of known F. hepatica infection status.This study is limited by the relatively small number of animals included, and the relatively short duration of the study period.Failure to establish infection after oral challenge raises fundamental questions on the pathophysiology and epidemiology of equine fasciolosis.

Establishment of an inactivated viral particle-based ELISA for the detection of anti-MERS-CoV antibodies

Objective To establish an inactivated viral particle-based ELISA for the detection of antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) in serum samples collected from a MERS-CoV associated case. Methods Serum samples were collected from 10 newborns and 40 healthy adults. A viral particle-based ELISA was established by using the inactivated MERS-CoV virions as antigen. The levels of IgM and IgG antibodies in the serum samples were detected by the established ELISA and the cut-off values for positive detection were determined. Then the inactivated MERS-CoV virion-based ELISA was used to detect the antibodies against MERS-CoV in 5 serum samples collected from the first imported MERS case in China. Results The cut-off values of IgM and IgG antibodies in serum samples for ELISA were determined to be A450 readings of 0.32 and 0.42, respectively. The titers of IgM and IgG antibodies in serum samples collected at early admission to hospital from the first imported MERS case in China were both 1︰40. Seroconversion occurred 2 weeks after his admission to hospital with the titers of IgM and IgG reaching to 1︰320. Conclusion The inactivated MERS-CoV virion-based ELISA was established successfully and could be used for the detection of serum antibodies (IgG and IgM) in MERS associated cases. Key words: Middle East respiratory syndrome; Coronavirus; Antibody; ELISA

Development of a DIVA ELISA for diagnosis of Aujeszky's disease using recombinant gE fused to thioredoxin as antigen

The major control methods for Aujeszky's Disease (AD) involve SHV1 gE gene-deleted vaccines and ELISA for detection of specific gE antibodies in infected animals, distinguishing infected animals from vaccinated animals (DIVA). This work aimed to develop a DIVA ELISA recombinant gE (gErec) for AD diagnosis using recombinant gE fused to thioredoxin protein. The analytical sensitivity and specificity were assessed with World Organisation for Animal Health (OIE) AD serum and sera from specific pathogen free (SPF), vaccinated SPF and AD-vaccinated SPF animals. The OIE serum reacted up to the recommended limit of detection and the other sera presented negative results. The cut-off point, diagnostic sensitivity and diagnostic specificity were determined by receiver operating curve analysis. This cut-off value corresponded to a diagnostic sensitivity of 97.60% and diagnostic specificity of 96.42%. Furthermore, two other cut-off points were chosen to discuss the ELISAgErec as a screening test in AD-endemic and free areas.

Design of a novel rapid immunoassay for simultaneous detection of hepatitis C virus core antigen and antibodies.

HCV is a potential cause of viral hepatitis, which leads to blood-borne chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Anti-HCV antibody detection assays detect HCV infection after approximately 70 days. HCV core antigen can be detected much earlier than anti-HCV antibodies. However, it disappears soon after the appearance of anti-HCV antibodies. Thus, there is a need for a rapid assay for simultaneous detection of HCV core antigen and anti-HCV antibodies for early diagnosis of HCV infection. A rapid diagnostic assay (HCV Ag-Ab Combo) for simultaneous detection of HCV core antigen and anti-HCV antibodies for early diagnosis of HCV infection was developed. HCV Ag-Ab Combo was evaluated in order to determine its potential for detection of HCV infection earlier than anti-HCV antibody detection assays. We compared the sensitivity of the newly developed assay with anti-HCV antibody detection assays (ELISA [HCV Ab ELISA] and rapid test [HCV Ab Rapid]) and HCV core antigen/anti-HCV antibody detection ELISA (HCV Ag-Ab ELISA). This study included 11 samples that were found positive in HCV RNA detection and HCV Ag-Ab ELISA but negative in HCV antibody detection assays (HCV Ab ELISA and rapid), 10 samples that were found positive in HCV Ag-Ab ELISA and HCV Ab ELISA but negative in HCV Ab Rapid, 69 samples that were found positive in HCV Ag-Ab ELISA, HCV Ab ELISA, and HCV Ab Rapid, and 509 samples that were found negative in HCV Ag-Ab ELISA, HCV Ab ELISA, and HCV Ab Rapid. Three seroconversion panels, PHV 913, PHV 911 (M) and PHV904-00-1.0, and aHCV RNA genotype qualification panel (2400-0182) acquired from Seracare Life Sciences (USA) were also tested. HCV Ag-Ab Combo showed a combined sensitivity and specificity of 100% when tested with 90 samples that were positive for HCV by HCV Ag-Ab ELISA and 509 HCV-negative samples. Its positive predictive value (PPV) and negative predictive value (NPV) were found to be 100%. It detected HCV infection approximately 7 to 12 days earlier than the HCV Ab detection assays, and its performance was not affected when testing different genotypes of HCV. HCV Ag-Ab Combo did not detect HCV infection as early as HCV RNA or HCV Ag-Ab ELISA. HCV Ag-Ab Combo provided a significant improvement for the early detection of HCV infection during the preseroconversion phase when compared with anti-HCV antibody detection assays. It could be a useful screening assay, and an alternative to HCV RNA detection or HCV Ag-Ab ELISA when nucleic acid technologies cannot be implemented.

Serological technique for detecting tuberculosis prevalence in sheep in Atlantic Spain

Recent studies show that sheep could be considered to be a maintenance host for the causative agents of animal tuberculosis (TB). The performance of diagnostic tests is not well established, and new tests need to be developed for this species. In addition, information about TB prevalence in sheep is scarce. Our objectives were to evaluate a new P22 ELISA for detection of specific antibodies against Mycobacterium tuberculosis Complex (MTC), and to assess the seropositivity in 3998 sheep from herds sampled in TB hotspot areas of northern Atlantic Spain with a low TB prevalence in cattle. Results based on 80 sheep of known infection status suggest excellent sensitivity and specificity (100% and 98%, respectively) even in a M. avium susbsp. paratuberculosis infected flock. The observed TB seroprevalence was 17.96% (698/3998; CI95% 16.31–18.67). Our results indicate that the P22 ELISA may constitute a good option for TB screening at the herd level in sheep, and that sheep are an important host and control programs should be implemented at least in hotspots or when cohabiting with other TB-infected species, i.e. cattle and goats.

Self-assembly into virus\u2013like particles of the recombinant capsid protein of porcine circovirus type 3 and its application on antibodies detection

PCV3 capsid protein (Cap) is an important antigen for diagnosis and vaccine development. To achieve high-level expression of recombinant PCV3 Cap in Escherichia coli (E. coli), the gene of wild-type entire Cap (wt-eCap) was amplified from clinical samples, and three optimized entire Cap (opti-eCap) and one optimized Cap deleted nuclear location signal (NLS) (opti-dCap) gene fragments encoding the same amino acid sequence with wt-eCap were synthesized based on the codon bias of E. coli. Those gene fragments were inserted into the pET30a expression vector. One recombinant strain with the highest expressed soluble eCap from four entire Cap (one wt-eCap and three opti-eCap) and one recombinant strain expressed opti-dCap were selected for further purification. The purified eCap and dCap were identified by transmission electron microscopy (TEM), a large number of round hollow particles with a diameter of 10 nm virus-like particles (VLPs) were observed in eCap, whereas irregular aggregation of proteins observed in dCap. After formation the VLPs were applied as a coating antigen to establish an indirect ELISA (I-ELISA) for detection of PCV3-specific antibody in swine serum. 373 clinical swine serum samples from China collected in 2019 were tested utilizing the VLP-based I-ELISA method under optimized conditions. To the best of our knowledge, this is the first report of self-assembly into VLPs of PCV3 recombinant Cap. Our results demonstrated that the VLP-based I-ELISA will be a valuable tool for detecting the presence of PCV3 antibodies in serum samples and will facilitate screening of large numbers of swine serum for clinical purposes.

Optimization of Recombinant Glycoprotein D (gD) based Indirect ELISA for Detection of Antibodies against Bovine Herpesvirus-1

Optimization of Recombinant Glycoprotein D (gD) based Indirect ELISA for Detection of Antibodies against Bovine Herpesvirus-1

Development and application of an antibody detection ELISA for Haemophilus parasuis based on a monomeric autotransporter passenger domain

BackgroundHaemophilus parasuis is a commensal pathogen in the swine upper respiratory tract and causes Glässer’s disease. Surveillance, screening for infection, and vaccination response of H. parasuis is hindered by the lack of a rapid antibody detection method.ResultsIn the present study, a monomeric autotransporter was identified as a novel antigen for developing an indirect ELISA. The autotransporter passenger domain (Apd) was expressed, purified, and demonstrated to be specific in ELISA and western blotting. Mouse antiserum of recombinant Apd (rApd) recognized native Apd in the 15 serotype reference strains and five non-typeable isolate stains, but showed no reaction with seven other bacterial pathogens. The rApd ELISA was optimized and validated using 67 serum samples with known background, including 27 positive sera from experimentally infected and vaccinated pigs along with 40 negative sera that had been screened with H. parasuis whole cell ELISA from clinically healthy herds. The rApd ELISA provided positive and negative percent agreements of 96.4 and 94.9%, respectively, and an AUC value of 0.961, indicating that the assay produced accurate results.ConclusionApd was a universal antigen component among 15 serotype and non-typeable strains of H. parasuis and was also specific to this pathogen. The rApd ELISA could detect antibodies elicited by H. parasuis infection and vaccination, thereby exhibiting the potential to be applied for Glässer’s disease diagnosis, H. parasuis vaccination evaluation, and large-scale serological surveillance.

Biotinylated Single-Domain Antibody-Based Blocking ELISA for Detection of Antibodies Against Swine Influenza Virus.

BackgroundEnzyme-linked immunosorbent assay (ELISA) is a common method for diagnosing swine influenza. However, the production of classical antibodies is both costly and time-consuming. As a promising alternative diagnostic tool, single-domain antibodies (sdAbs) offer the advantages of simpler and faster generation, good stability and solubility, and high affinity and specificity.MethodsPhage display technology was used to isolate sdAbs against the SIV-NP protein from a camel VHH library. The sdAb5 was fused to the biotin acceptor peptide (BAP) and a His-Tag for its expression as monomeric and site-specific biotinylation in E.coli to develop an sdAb-based blocking ELISA (sdAb-ELISA). In the sdAb-ELISA, the anti-SIV antibodies from swine samples were used to block the binding between the biotinylated sdAb5 and SIV-NP protein coated on the ELISA plate. The specificity, sensitivity, and reproducibility of sdAb-ELISA were determined. In addition, consistency among sdAb-ELISA, commercial ELISA kit, and Western blot was evaluated.ResultsSix SIV-NP-specific sdAbs were isolated, among which sdAb5 was identified as a dominant sdAb with higher reactivity. The cut-off value of biotinylated sdAb5-based bELISA was determined to be 29.8%. Compared with the positive reference serum against five different types of swine viruses, the developed sdAb-ELISA showed 100% specificity. The detection limit of sdAb-ELISA was 1:160 in an anti-SIV positive reference serum, which is lower than that of the commercial ELISA kit (1:20). In 78 diluted anti-SIV positive serum (1:80), 21 and 42 samples were confirmed as positive by the commercial ELISA kit and sdAb-ELISA, respectively. The coefficients of variation of intra- and inter-assay were 1.79–4.57% and 5.54–9.98%, respectively. The sdAb-ELISA and commercial ELISA kit showed a consistency of 94.17% in clinical swine serum samples. Furthermore, the coincidence rate was 96.67% between the results detected by sdAb-ELISA and Western blot.ConclusionA specific, sensitive, and reproducible sdAb-ELISA was successfully developed, which offers a new, promising method to detect anti-SIV antibodies in swine serum.

Bead-Based Multiplex Assay for the Simultaneous Detection of Antibodies to African Swine Fever Virus and Classical Swine Fever Virus

African swine fever (ASF) and Classical swine fever (CSF) are both highly contagious diseases of domestic pigs and wild boar. In the last years, several cases of both diseases have been reported in the Caucasus, Russian Federation and Eastern Europe. Thus, the probability of encountering these two viruses in the same area is increasing. Since differentiation by clinical or post-mortem examination is not possible, laboratory tools for differential diagnosis are required. In the present work, we have developed a triplex bead-based assay using some of the most immunogenic antigens of each virus, for the simultaneous detection of antibodies; i.e. the VP72 and VP30 of ASF virus (ASFV) and the E2 protein of CSF virus (CSFV). The assay was firstly set up and optimized using well characterized reference serum samples specific for each pathogen. Then, a panel of 352 sera from experimentally infected animals with either ASFV or CSFV were analyzed in the multiplex assay. A collection of 253 field negative sera was also included in the study. The results of the multiplex analysis were compared to those obtained by two commercially available ELISAs for detection of antibodies against ASFV or CSFV, and considered in this study as the reference techniques. The data obtained showed values of 97.3% sensitivity and 98.3% specificity for detection of antibodies to ASFV and 95.7% of sensitivity and 99.8% specificity for detection of antibodies to CSFV. This multiplex assay allows the simultaneous and differential detection of antibodies against ASFV and CSFV, providing a valuable tool for surveillance studies. Moreover, this method is rather versatile, offering the possibility of increasing the panel of antigens from other swine diseases that could be of interest for a differential diagnosis along with ASF and CSF.

Comparison of Two Rift Valley Fever Serological Tests in Cameroonian Cattle Populations Using a Bayesian Latent Class Approach.

Rift Valley Fever is an important zoonotic viral disease of livestock occurring across much of Africa causing acute febrile illness, abortion, and neonatal death in livestock particularly sheep and cattle and a range of disease in humans from mild flu-like symptoms to more severe haemorrhagic fever and death. Understanding the epidemiology requires well-evaluated tools including antibody detection ELISAs. It is well-recognized that tests developed in one population do not necessarily perform as well when used in different populations and it is therefore important to assess tests in the populations in which they are to be used. Here we describe the performance of a commercial RVF ELISA (ID.Vet) and an in-house plaque reduction neutralization test (PRNT80). A Bayesian no gold standard latent class model for two tests and ≥2 populations based on the Hui-Walter model was used to estimate the test parameters using a range of populations based on geographical separation and age to assess consistency of performance across different sub-populations. The ID.Vet ELISA had an estimated diagnostic sensitivity (Se) of 0.854 (0.655–0.991 95%BCI) and specificity (Sp) of 0.986 (0.971–0.998 95%BCI) using all the data and splitting the population by geographical region compared to 0.844 (0.660–0.973 95%BCI) and 0.981 (0.965–0.996 95%BCI) for the PRNT80. There was slight variation in the mean Se and Sp in different sub-populations mainly in Se estimates due to small numbers of positives in the sub-populations but the 95% BCI generally overlapped suggesting a very consistent performance across the different geographical areas and ages of animals. This is one of few reports of serological evidence of RVF in Central Africa and strongly suggests the virus is actively circulating in this cattle population. This has important public health implications and RVF should be considered as a differential in both livestock disease cases as well as human febrile cases in West and Central Africa not just East Africa. We also demonstrate that the performance of the commercial ELISA is comparable to the PRNT80 but has the advantages of speed, lower cost and no containment needs making it a much more useful test for low and middle income settings (LMICs).

Development of an indirect ELISA for detection of antibody against peste des petits ruminants virus in sheep

Background: Emergence of exotic viral disease like peste des petits ruminants(PPR) possesses a great threat towards successful goat and sheep farming in Bangladesh. Implementation of effective control measures against PPR requires a proper and rapid diagnosis of the disease. Various diagnostic techniques are available for diagnosis of PPR in goats and sheep in Bangladesh. Among these, ELISA is an important technique to diagnose the disease as well as for seromonitoring. However, the ELISA kits that are being used in the country are mostly imported. This study was undertaken to develop an in-house indirect ELISA using local PPR virus isolate as an antigen.Methods: A local isolate of PPR virus (PPRV) was used as an antigen to develop an indirect ELISA kit. Standardization of the optimum antibody, conjugate and virus antigen concentration was performed using chequer-board titration with different dilutions of the reagents. Finally, the developed indirect ELISA kit was used in a pilot study to detect anti-PPRV antibodies in sheep sera samples.Results: A polyclonal antibody based indirect ELISA was developed successfully for the detection of PPRV antibodies. The developed ELISA could detect anti-PPRV antibody in sheep sera sample during our pilot field trial.Conclusions: After robust field validation, the indirect ELISA can be used to determine the antibody titer against PPRV in the field as to monitor the seroconversion after vaccination.

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.

Fasciola hepatica in UK horses.

SummaryBackground Fasciola hepatica (liver fluke) affects grazing animals including horses but the extent to which it affects UK horses is unknown.ObjectivesTo define how liver fluke affects the UK horse population.Study designDescriptive, cross‐sectional, observational study.MethodsAn F. hepatica excretory‐secretory antibody detection ELISA with a diagnostic sensitivity of 71% and specificity of 97% was validated and used to analyse serum samples. An abattoir study was performed to determine prevalence. A case‐control study of 269 horses compared fluke exposure between horses with liver disease and controls. Data on clinical signs and blood test results were collected for sero‐positive horses. Genotyping of adult fluke was used to produce a multilocus genotype for each parasite.ResultsFour (2.2%) of 183 horses registered in the UK, sampled in the abattoir, had adult flukes in the liver, and the sero‐prevalence of F. hepatica was estimated as 8.7%. In the case‐control study, horses showing signs consistent with liver disease had significantly higher odds of testing positive for F. hepatica on ELISA than control horses. In 23 sero‐positive horses, a range of non‐specific clinical signs and blood test abnormalities was reported, with a third of the horses showing no signs. Genotypic analysis of liver flukes from horses provided evidence that these came from the same population as flukes from sheep and cattle.Main limitationsBias could have arisen in the prevalence and case‐control studies due to convenience sampling methods, in particular the geographic origin of the horses. Only a small number of horses tested positive so the data on clinical signs are limited.ConclusionsExposure to liver fluke occurs frequently in horses and may be an under‐recognised cause of liver disease. Flukes isolated from horses are from the same population as those found in ruminants. When designing and implementing parasite control plans, fluke should be considered, and horses should be tested if appropriate.