TY - JOUR T1 - Molecular and virological characterization of the first poultry outbreaks of Genotype VII.2 velogenic avian orthoavulavirus type 1 (NDV) in North-West Europe, BeNeLux, 2018. JF - Transbound Emerg Dis Y1 - 2021 A1 - Mieke Steensels A1 - Steven Van Borm A1 - Ingeborg Mertens A1 - Houdart, Philippe A1 - Fabienne Rauw A1 - Virginie Roupie A1 - Chantal J Snoeck A1 - Manon Bourg A1 - Serge Losch A1 - Nancy Beerens A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Animals KW - Chickens KW - Disease Outbreaks KW - Europe KW - Genotype KW - Newcastle Disease KW - Newcastle disease virus KW - Phylogeny KW - Poultry KW - Poultry Diseases AB -

After two decades free of Newcastle disease, Belgium encountered a velogenic avian orthoavulavirus type 1 epizootic in 2018. In Belgium, 20 cases were diagnosed, of which 15 occurred in hobby flocks, 2 in professional poultry flocks and 3 in poultry retailers. The disease also disseminated from Belgium towards the Grand Duchy of Luxembourg by trade. Independently, the virus was detected once in the Netherlands, almost simultaneously to the first Belgian detection. As such Newcastle disease emerged in the entire BeNeLux region. Both the polybasic sequence of the fusion gene cleavage site and the intracerebral pathotyping assay demonstrated the high pathogenicity of the strain. This paper represents the first notification of this specific VII.2 subgenotype in the North-West of Europe. Time-calibrated full genome phylogenetic analysis indicated the silent or unreported circulation of the virus prior to the emergence of three genetic clusters in the BeNeLux region without clear geographical or other epidemiological correlation. The Dutch strain appeared as an outgroup to the Belgian and Luxembourgian strains in the time-correlated genetic analysis and no epidemiological link could be identified between the Belgian and Dutch outbreaks. In contrast, both genetic and epidemiological outbreak investigation data linked the G.D. Luxembourg case to the Belgian outbreak. The genetic links between Belgian viruses from retailers and hobby flocks only partially correlated with epidemiological data. Two independent introductions into the professional poultry sector were identified, although their origin could not be determined. Animal experiments using 6-week- old specific pathogen-free chickens indicated a systemic infection and efficient transmission of the virus. The implementation of re-vaccination in the professional sector, affected hobby and retailers, as well as the restriction on assembly and increased biosecurity measures, possibly limited the epizootic and resulted in the disappearance of the virus. These findings emphasize the constant need for awareness and monitoring of notifiable viruses in the field.

VL - 68 CP - 4 M3 - 10.1111/tbed.13863 ER - TY - JOUR T1 - Molecular and virological characterization of the first poultry outbreaks of Genotype VII.2 velogenic avian orthoavulavirus type 1 (NDV) in North‐West Europe, BeNeLux, 2018 JF - Transboundary and Emerging Diseases Y1 - 2021 A1 - Mieke Steensels A1 - Steven Van Borm A1 - Ingeborg Mertens A1 - Houdart, Philippe A1 - Fabienne Rauw A1 - Virginie Roupie A1 - Chantal J. Snoeck A1 - Manon Bourg A1 - Serge Losch A1 - Nancy Beerens A1 - Thierry van den Berg A1 - Bénédicte Lambrecht VL - 68 CP - 4 M3 - 10.1111/tbed.13863 ER - TY - JOUR T1 - Atypical Pathogenicity of Avian Influenza (H3N1) Virus Involved in Outbreak, Belgium, 2019 JF - Emerging Infectious Diseases Y1 - 2020 A1 - Mieke Steensels A1 - Philippe Lagacé-Wiens A1 - Steven Van Borm A1 - Thierry van den Berg A1 - Mickael Cargnel A1 - Virginie Roupie A1 - Fabienne Rauw A1 - Bénédicte Lambrecht VL - 26 CP - 8 M3 - 10.3201/eid2608.191338 ER - TY - JOUR T1 - Atypical Pathogenicity of Avian Influenza (H3N1) Virus Involved in Outbreak, Belgium, 2019 JF - Emerging Infectious Diseases Y1 - 2020 A1 - Mieke Steensels A1 - Philippe Lagacé-Wiens A1 - Steven Van Borm A1 - Thierry van den Berg A1 - Corrigan, Tim A1 - Virginie Roupie A1 - Fabienne Rauw A1 - Bénédicte Lambrecht AB -

In 2019, an outbreak of avian influenza (H3N1) virus infection occurred among commercial poultry in Belgium. Full-genome phylogenetic analysis indicated a wild bird origin rather than recent circulation among poultry. Although classified as a nonnotifiable avian influenza virus, it was associated with reproductive tropism and substantial mortality in the field.

VL - 26 CP - 8 M3 - 10.3201/eid2608.191338 ER - TY - JOUR T1 - Study of the underlying mechanisms and consequences of pathogenicity differences between two in vitro selected G1-H9N2 clones originating from a single isolate. JF - Vet Res Y1 - 2019 A1 - Nguyen Giang Thu A1 - Fabienne Rauw A1 - Mieke Steensels A1 - Ingrao, Fiona A1 - Bonfante, Francesco A1 - Irit Davidson A1 - Bénédicte Lambrecht KW - Animals KW - Chickens KW - Gene Expression Regulation KW - Genome, Viral KW - Hemagglutination Inhibition Tests KW - Immunity, Innate KW - In Vitro Techniques KW - Influenza A Virus, H9N2 Subtype KW - Influenza in Birds KW - Poultry Diseases KW - Real-Time Polymerase Chain Reaction KW - Sequence Analysis, DNA KW - Viral Plaque Assay KW - virulence KW - Virus Shedding AB -

The G1-H9N2 avian influenza virus (AIV) has caused significant economic losses in the commercial poultry industry due to reduced egg production and increased mortality. The field observations have shown that H9N2 viruses circulate and naturally mix with other pathogens and these simultaneous infections can exacerbate disease. To avoid an incorrect virus characterization, due to co-infection, isolates were purified by in vitro plaque assays. Two plaque purified G1-H9N2 clones, selected on different cell types, named MDCK-and CEF-clone in regards to the cell culture used, were studied in vivo, revealing two different virulence phenotypes. Subsequently, the underlying mechanisms were studied. Specifically, the phenotypical outcome of SPF bird infection by the two clones resulted in completely different clinical outcomes. These differences in clinical outcome were used to study the factors behind this output in more detail. Further studies demonstrated that the more severe disease outcome associated with the MDCK-clone involves a strong induction of pro-inflammatory cytokines and a lack of type I interferon production, whereas the mild disease outcome associated with the CEF-clone is related to a greater antiviral cytokine response. The immunosuppressive effect of the MDCK-clone on splenocytes was further demonstrated via ChIFN-γ lack production after ex vivo mitogenic stimulation. Genome sequencing of the two clones identified only four amino acid differences including three in the HA sequence (HA-E198A, HA-R234L, HA-E502D-H9 numbering) and one in the NA sequence (NA-V33M). In the present study, valuable insights on the mechanisms responsible for AI pathogenicity and molecular mechanisms of H9N2 infections in chicken were obtained while highlighting the impact of the cells viruses are grown on their virulence.

VL - 50 CP - 1 M3 - 10.1186/s13567-019-0635-1 ER - TY - JOUR T1 - Early immune responses and profiling of cell-mediated immunity-associated gene expression in response to rHVT-IBD vaccination JF - Vaccine Y1 - 2018 A1 - Ingrao, Fiona A1 - Fabienne Rauw A1 - Mieke Steensels A1 - Thierry van den Berg A1 - Bénédicte Lambrecht VL - 36 M3 - 10.1016/j.vaccine.2017.12.059 ER - TY - JOUR T1 - Characterization of two recombinant HVT-IBD vaccines by VP2 insert detection and cell-mediated immunity after vaccination of specific pathogen-free chickens. JF - Avian Pathol Y1 - 2017 A1 - Ingrao, Fiona A1 - Fabienne Rauw A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Animals KW - Antibodies, Viral KW - Birnaviridae Infections KW - Chickens KW - Enzyme-Linked Immunosorbent Assay KW - Herpesvirus 1, Meleagrid KW - Immunity, Cellular KW - Infectious bursal disease virus KW - Interferon-gamma KW - Male KW - Poultry Diseases KW - Specific Pathogen-Free Organisms KW - Vaccination KW - Vaccines, Synthetic KW - Viral Structural Proteins KW - Viral Vaccines AB -

Infectious bursal disease (IBD) is an avian viral disease that causes severe economic losses in the poultry industry worldwide. The live IBD virus (IBDV) has a potential immunosuppressive effect. Currently available IBDV vaccines have shortcomings, prompting the development of safer and more effective vaccination approaches, including the use of the recombinant turkey herpesvirus vaccine expressing the immunogenic structural VP2 protein of IBDV (recombinant HVT (rHVT)-IBD). The objectives of this study were twofold: (i) to develop in vitro assays and molecular tools to detect the VP2 protein and gene and (ii) to evaluate cell-mediated immunity (CMI) induced by rHVT-IBD vaccination of day-old specific pathogen-free chickens. The VP2 protein expressed by rHVT-IBD-infected chicken embryo fibroblasts was detected using the enzyme-linked immunosorbent assay and immunofluorescence. Using molecular techniques, the VP2 gene was detected in various organs, providing a method to monitor vaccine uptake. rHVT-IBD vaccination induced CMI responses in specific pathogen-free chickens at 5 weeks. CMI was detected by measuring chicken interferon-gamma after ex vivo antigenic stimulation of splenocytes. Moreover, our results showed that the enzyme-linked immunospot approach is more sensitive in detecting chicken interferon-gamma than enzyme-linked immunosorbent assay. The tools developed in this study may be useful in the characterization of new-generation recombinant vaccines and the cellular immune response they induce.

VL - 46 CP - 3 U1 - https://www.ncbi.nlm.nih.gov/pubmed/27897452?dopt=Abstract M3 - 10.1080/03079457.2016.1265083 ER - TY - JOUR T1 - Specific antibody-mediated immunity in the reproductive tract of laying chickens immunized against Newcastle disease with conventional attenuated and inactivated vaccines. JF - Avian Pathol Y1 - 2017 A1 - Fabienne Rauw A1 - Nguyen, T G A1 - Ngabirano, E A1 - Sylvie Marché A1 - Bénédicte Lambrecht AB -

Despite the widespread and successful use of Newcastle disease (ND) vaccines, Newcastle disease virus (NDV) can seriously injure the reproductive tract of egg-laying hens, leading to rapid egg-drop and poor shell quality. Few published studies investigated local NDV-specific immune response in the reproductive tract after ND vaccination of hens. The present study investigated, for the first time, local NDV-specific antibody-mediated immunity in segments of the oviduct during the laying period. Specific pathogen-free (SPF) White Leghorn chickens were immunized following an ND vaccination programme applied in the field, which combined ND-attenuated vaccine (inoculated subcutaneously at one day, 2 weeks and 11 weeks of age) with inactivated vaccine (inoculated intramuscularly at 17 weeks). The infundibulum, magnum, isthmus and uterus (segments of the reproductive tract) were harvested at 28 weeks and 32 weeks of age (during the laying period). Supernatant from ex vivo tissue culture was collected and tested by: (i) haemagglutination inhibition (HI) test, (ii) commercial IDVet ND-enzyme-linked immunosorbent assay (ELISA) and (iii) NDV-specific IgG, IgM and IgA in-house ELISAs. For all sampling time points and oviduct segments, all samples were positive for commercial ND-ELISA and in-house ELISA-IgG. However, six of these ELISA-IgG positive samples yielded negative results when submitted to the HI test. Interestingly, NDV-specific IgM and IgA were detected frequently in the infundibulum and magnum as compared to the isthmus and uterus. These results show that the antibody immune response in the oviduct was induced by the timing of attenuated and inactivated ND vaccinations.

VL - 46 CP - 4 U1 - http://www.ncbi.nlm.nih.gov/pubmed/28290220?dopt=Abstract M3 - 10.1080/03079457.2017.1304528 ER - TY - JOUR T1 - Experimental and Field Results Regarding Immunity Induced by a Recombinant Turkey Herpesvirus H5 Vector Vaccine Against H5N1 and Other H5 Highly Pathogenic Avian Influenza Virus Challenges. JF - Avian Dis Y1 - 2016 A1 - Gardin, Yannick A1 - Palya, Vilmos A1 - Dorsey, Kristi Moore A1 - El-Attrache, John A1 - Bonfante, Francesco A1 - Wit, Sjaak de A1 - Kapczynski, Darrell A1 - Kilany, Walid Hamdy A1 - Fabienne Rauw A1 - Mieke Steensels A1 - Soejoedono, Retno D KW - Animals KW - Birds KW - Chickens KW - Genetic Vectors KW - Herpesvirus 1, Meleagrid KW - Influenza A virus KW - Influenza A Virus, H5N1 Subtype KW - Influenza in Birds KW - Influenza Vaccines KW - Poultry Diseases KW - Vaccination KW - virulence AB -

Vaccination against H5N1 highly pathogenic avian influenza (AI) virus (HPAIV) is one of the possible complementary means available for affected countries to control AI when the disease has become, or with a high risk of becoming, endemic. Efficacy of the vaccination against AI relies essentially, but not exclusively, on the capacity of the vaccine to induce immunity against the targeted virus (which is prone to undergo antigenic variations), as well as its capacity to overcome interference with maternal immunity transmitted by immunized breeding hens to their progeny. This property of the vaccine is a prerequisite for its administration at the hatchery, which assures higher and more reliable vaccine coverage of the populations than vaccination at the farm. A recombinant vector vaccine (Vectormune® AI), based on turkey herpesvirus expressing the hemagglutinin gene of an H5N1 HPAIV as an insert, has been used in several experiments conducted in different research laboratories, as well as in controlled field trials. The results have demonstrated a high degree of homologous and cross protection against different genetic clades of the H5N1 HPAIV. Furthermore, vaccine-induced immunity was not impaired by the presence of passive immunity, but on the contrary, cumulated with it for improved early protection. The demonstrated levels of protection against the different challenge viruses exhibited variations in terms of postchallenge mortality, as well as challenge virus shedding. The data presented here highlight the advantages of this vaccine as a useful and reliable tool to complement biosecurity and sanitary policies for better controlling the disease due to HPAIV of H5 subtypes, when the vaccination is applied as a control measure.

VL - 60 CP - 1 Suppl U1 - http://www.ncbi.nlm.nih.gov/pubmed/27309060?dopt=Abstract M3 - 10.1637/11144-050815-ResNote ER - TY - JOUR T1 - Protection Afforded by a Recombinant Turkey Herpesvirus-H5 Vaccine Against the 2014 European Highly Pathogenic H5N8 Avian Influenza Strain. JF - Avian Dis Y1 - 2016 A1 - Mieke Steensels A1 - Fabienne Rauw A1 - Thierry van den Berg A1 - Sylvie Marché A1 - Gardin, Y A1 - Palya, V A1 - Bénédicte Lambrecht KW - Animals KW - Chickens KW - Europe KW - Galliformes KW - Genetic Vectors KW - Herpesvirus 1, Meleagrid KW - Influenza A Virus, H5N1 Subtype KW - Influenza A Virus, H5N8 Subtype KW - Influenza in Birds KW - Influenza Vaccines KW - Vaccination KW - Vaccines, Synthetic AB -

A highly pathogenic avian influenza (HPAI) H5N8 (clade 2.3.4.4) virus, circulating in Asia (South Korea, Japan, and southern China) since the beginning of 2014, reached the European continent in November 2014. Germany, the Netherlands, the United Kingdom, Italy, and Hungary confirmed H5N8 infection of poultry farms of different species and of several wild bird species. Unlike the Asian highly pathogenic (HP) H5N1, this HP H5N8 also went transatlantic and reached the American West Coast by the end of 2014, affecting wild birds as well as backyard and commercial poultry. This strain induces high mortality and morbidity in Galliformes, whereas wild birds seem only moderately affected. A recombinant turkey herpesvirus (rHVT) vector vaccine expressing the H5 gene of a clade 2.2 H5N1 strain (rHVT-H5) previously demonstrated a highly efficient clinical protection and reduced viral excretion against challenge with Asian HP H5N1 strains of various clades (2.2, 2.2.1, 2.2.1.1, 2.1.3, 2.1.3.2, and 2.3.2.1) and was made commercially available in various countries where the disease is endemic. To evaluate the protective efficacy of the rHVT-H5 vaccine against the first German H5N8 turkey isolate (H5N8 GE), a challenge experiment was set up in specific-pathogen-free (SPF) chickens, and the clinical and excretional protection was evaluated. SPF chickens were vaccinated subcutaneously at 1 day old and challenged oculonasally at 4 wk of age with two viral dosages, 10(5) and 10(6) 50% egg infective doses. Morbidity and mortality were monitored daily in unvaccinated and vaccinated groups, whereas viral shedding by oropharyngeal and cloacal routes was evaluated at 2, 5, 9, and 14 days postinoculation (dpi). Serologic monitoring after vaccination and challenge was also carried out. Despite its high antigenic divergence of the challenge H5N8 strain, a single rHVT-H5 vaccine administration at 1 day old resulted in a full clinical protection against challenge and a significant reduction of viral shedding in the vaccinated birds.

VL - 60 CP - 1 Suppl U1 - http://www.ncbi.nlm.nih.gov/pubmed/27309056?dopt=Abstract M3 - 10.1637/11126-050615-Reg.1 ER - TY - JOUR T1 - Quantification of rHVT-F genome load in feather follicles by specific real-time qPCR as an indicator of NDV-specific humoral immunity induced by day-old vaccination in SPF chickens. JF - Avian Pathol Y1 - 2015 A1 - Fabienne Rauw A1 - Steven Van Borm A1 - Sarah Welby A1 - Ngabirano, E A1 - Gardin, Y A1 - Palya, V A1 - Bénédicte Lambrecht KW - Animals KW - Bursa of Fabricius KW - Chickens KW - Enzyme-Linked Immunosorbent Assay KW - Feathers KW - Fluorescence KW - Genetic Load KW - Herpesvirus Vaccines KW - Immunity, Humoral KW - Lung KW - Models, Genetic KW - Newcastle Disease KW - Oligonucleotides KW - Real-Time Polymerase Chain Reaction KW - Specific Pathogen-Free Organisms KW - Turkey KW - Vaccination AB -

The purpose of this study was to look for a reliable molecular method for confirmation of uptake of recombinant turkey herpesvirus vaccine against Newcastle disease (rHVT-F) and for use as a valuable prediction tool of Newcastle disease virus (NDV)-specific immune response in chickens deprived of maternally derived antibody (MDA). A quantitative real-time polymerase chain reaction (real-time qPCR) specific to rHVT-F was developed. The method was applied to various tissue samples taken from specific pathogen free (SPF) chickens experimentally inoculated at day-old with one dose of rHVT-F vaccine over a 6-week period. Among the tested tissues, the rHVT-F vaccine was detected predominantly in the bursa of Fabricius (BF) and the lung for the first week, followed by a progressive decline from 9 days onwards. Then, an increase of genome load was observed in the feather follicles (FF) with a peak at 2 weeks, rising to a level almost 10(3)-fold greater than in the other tissues. Importantly, the rHVT-F genome load in FF appeared to be strongly correlated to the humoral immunity specific to NDV as evaluated by haemagglutination inhibition (HI) test and NDV-specific IgG, IgM and IgA ELISAs. This is the first report of quantification of rHVT-F vaccine in FF and its correlation with the induction of ND-specific immune response in chickens with no MDA. Our data indicate that the application of this real-time qPCR assay on FF samples taken from chickens in the field may be used to confirm rHVT-F vaccine administration and uptake with the important added benefit of offering a non-disruptive sampling procedure.

VL - 44 CP - 3 U1 - https://www.ncbi.nlm.nih.gov/pubmed/25687165?dopt=Abstract M3 - 10.1080/03079457.2015.1018869 ER - TY - JOUR T1 - The combination of attenuated Newcastle disease (ND) vaccine with rHVT-ND vaccine at 1 day old is more protective against ND virus challenge than when combined with inactivated ND vaccine. JF - Avian Pathol Y1 - 2014 A1 - Fabienne Rauw A1 - Gardin, Y A1 - Palya, V A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Animals KW - Chickens KW - Enzyme-Linked Immunosorbent Assay KW - Herpesvirus 1, Meleagrid KW - Newcastle Disease KW - Newcastle disease virus KW - Poultry Diseases KW - Statistics, Nonparametric KW - Th1 Cells KW - Vaccines, Attenuated KW - Vaccines, Synthetic KW - Viral Fusion Proteins KW - Viral Vaccines AB -

The recurrent outbreaks of fatal Newcastle disease (ND) in commercial poultry flocks throughout the world indicate that routine vaccinations are failing to sufficiently induce the high levels of immunity necessary to control ND. There is a need for vaccination programmes that could be initiated at 1-day-old for mass application and which would induce a long-lasting immunity, with no need for a booster vaccination at a later age. In this context, the duration of immunity delivered by a vaccination programme including a recombinant herpesvirus of turkeys expressing the F gene of ND virus (rHVT-ND) and live ND vaccine at 1-day-old was compared with a classical programme that included a conventional live and an inactivated ND vaccine at the same age in commercial layer chickens. The humoral, cell-mediated and local immunity were followed weekly and birds were challenged with a viscerotropic velogenic ND virus strain at 6 and 10 weeks of age. We determined that immunity induced by the vaccination programme involving the rHVT-ND vaccine was more protective than that provided by the conventional vaccine-based regime. This might be related to a T-helper type 1 (Th1) cellular-driven immunological response, in contrast to the T-helper type 2 (Th2) humoral-oriented immune response provided by the current conventional vaccine-based vaccination programmes.

VL - 43 CP - 1 U1 - http://www.ncbi.nlm.nih.gov/pubmed/24283258?dopt=Abstract M3 - 10.1080/03079457.2013.859655 ER - TY - JOUR T1 - Comparison of single 1-day-old chick vaccination using a Newcastle disease virus vector with a prime/boost vaccination scheme against a highly pathogenic avian influenza H5N1 challenge. JF - Avian Pathol Y1 - 2014 A1 - Ferreira, Helena Lage A1 - Fabienne Rauw A1 - Pirlot, Jean François A1 - Reynard, Frédéric A1 - Thierry van den Berg A1 - Bublot, Michel A1 - Bénédicte Lambrecht KW - Animals KW - Animals, Newborn KW - Chickens KW - Genetic Vectors KW - Immunity, Humoral KW - Influenza A Virus, H5N1 Subtype KW - Influenza in Birds KW - Newcastle disease virus KW - Poultry Diseases KW - Viral Vaccines KW - Virus Shedding AB -

Avian influenza (AI) vaccines should be used as part of a whole comprehensive AI control programme. Vectored vaccines based on Newcastle disease virus (NDV) are very promising, but are so far licensed in only a few countries. In the present study, the immunogenicity and protection against a highly pathogenic H5N1 influenza challenge were evaluated after vaccination with an enterotropic NDV vector expressing an H5 haemagglutinin (rNDV-H5) in 1-day-old specific pathogen free chickens inoculated once, twice or once followed by a heterologous boost with an inactivated H5N9 vaccine (iH5N9). The heterologous prime/boost rNDV-H5/iH5N9 combination afforded the best level of protection against the H5N1 challenge performed at 6 weeks of age. Two rNDV-H5 administrations conferred a good level of protection after challenge, although only a cellular H5-specific response could be detected. Interestingly, a single administration of rNDV-H5 gave the same level of protection as the double administration but without any detectable H5-specific immune response. In contrast to AI immunity, a high humoral, mucosal and cellular NDV-specific immunity could be detected up to 6 weeks post vaccination after using the three different vaccination schedules. NDV-specific mucosal and cellular immune responses were slightly higher after double rNDV-H5 vaccination when compared with single inoculation. Finally, the heterologous prime/boost rNDV-H5/iH5N9 combination induced a broader detectable immunity including systemic, mucosal and cellular AI and NDV-specific responses.

VL - 43 CP - 1 U1 - http://www.ncbi.nlm.nih.gov/pubmed/24320551?dopt=Abstract M3 - 10.1080/03079457.2013.873111 ER - TY - JOUR T1 - Infectious Bursal Disease: a complex host-pathogen interaction. JF - Dev Comp Immunol Y1 - 2013 A1 - Ingrao, Fiona A1 - Fabienne Rauw A1 - Bénédicte Lambrecht A1 - Thierry van den Berg KW - Animals KW - Antibodies, Viral KW - B-Lymphocytes KW - Birnaviridae Infections KW - Bursa of Fabricius KW - Chickens KW - Cytokines KW - Host-Pathogen Interactions KW - Immunity, Innate KW - Immunocompromised Host KW - Infectious bursal disease virus KW - Macrophage Activation KW - Macrophages KW - T-Lymphocytes KW - Viral Vaccines AB -

Infectious Bursal Disease (IBD) is caused by a small, non-enveloped virus, highly resistant in the outside environment. Infectious Bursal Disease Virus (IBDV) targets the chicken's immune system in a very comprehensive and complex manner by destroying B lymphocytes, attracting T cells and activating macrophages. As an RNA virus, IBDV has a high mutation rate and may thus give rise to viruses with a modified antigenicity or increased virulence, as emphasized during the last decades. The molecular basis of pathogenicity and the exact cause of clinical disease and death are still poorly understood, as it is not clearly related to the severity of the lesions and the extent of the bursal damage. Recent works however, pointed out the role of an exacerbated innate immune response during the early stage of the infection with upregulated production of promediators that will induce a cytokine storm. In the case of IBDV, immunosuppression is both a direct consequence of the infection of specific target immune cells and an indirect consequence of the interactions occurring in the immune network of the host. Recovery from disease or subclinical infection will be followed by immunosuppression with more serious consequences if the strain is very virulent and infection occurs early in life. Although the immunosuppression caused by IBDV is principally directed towards B-lymphocytes, an effect on cell-mediated immunity (CMI) has also been demonstrated therefore increasing the impact of IBDV on the immunocompetence of the chicken. In addition to its zootechnical impact and its role in the development of secondary infections, it may affect the immune response of the chicken to subsequent vaccinations, essential in all types of intensive farming. Recent progress in the field of avian immunology has allowed a better knowledge of the immunological mechanisms involved in the disease but also should give improved tools for the measurement of immunosuppression in the field situation. Although satisfactory protection may be provided by the induction of high neutralizing antibody titres, interference from parental antibodies with vaccination has become the most important obstacle in the establishment of control programs. In this context, recombinant HVT and immune complex vaccines show promising results.

VL - 41 CP - 3 U1 - https://www.ncbi.nlm.nih.gov/pubmed/23567344?dopt=Abstract M3 - 10.1016/j.dci.2013.03.017 ER - TY - JOUR T1 - Setting up a SPF chicken model for the pathotyping of West Nile virus (WNV) strains. JF - Transbound Emerg Dis Y1 - 2013 A1 - Dridi, M A1 - Fabienne Rauw A1 - Muylkens, B A1 - Lecollinet, S A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Animals KW - Antibodies, Viral KW - Belgium KW - Chickens KW - Disease Outbreaks KW - Enzyme-Linked Immunosorbent Assay KW - Follow-Up Studies KW - Real-Time Polymerase Chain Reaction KW - RNA, Viral KW - Viremia KW - West Nile Fever KW - West Nile virus AB -

Birds play a central role in WNV epidemiology by spreading and amplifying the virus. Increasing numbers of WNV isolates are detected in Europe, and the virulence of these genetically variable isolates is not well characterized for birds. Therefore, we investigated whether SPF chickens could be a valuable avian model for the pathotyping of WNV strains. One-day-old SPF chickens were inoculated subcutaneously (SC) or intracerebrally (IC) with four lineage 1 WNV strains (Is98, It2008, Fr2000 or Kunjin) and were daily clinically monitored for 2 weeks after infection. Additionally, one-day-old SPF chickens were SC inoculated, and one-week-old SPF chickens were SC or IC inoculated with two Euro-Mediterranean isolates, Is98 and Fr2000, to sample blood and feathers at regular time points. These samples were analysed by WN NS2a-specific rRT-PCR and WN NS1 antigen-capture ELISA that were developed for the purpose of this study. Differences in strain virulence were evidenced after IC inoculation of one-day-old SPF chickens, with Is98 eliciting the highest mortality rates and Kunjin the lowest ones, while lethality of Fr2000 and It2008 was intermediate. Neither viral load in sera and feathers nor NS1 antigen in the serum correlated with the differential pathogenicity of Is98 and Fr2000. However, irrespective of the inoculated strain, younger chickens showed higher and longer-lasting viremias than older chickens. In all experimental groups, the detection window for viral RNA in feathers lasted up to 14 dpi. Altogether, the data presented in this study show that WNV strain virulence can be discriminated in a one-day-old SPF chicken model on the basis of mortality rates, while viremia and viral load in feathers appear to be age dependent rather than strain dependent.

VL - 60 Suppl 2 U1 - http://www.ncbi.nlm.nih.gov/pubmed/24589102?dopt=Abstract M3 - 10.1111/tbed.12144 ER - TY - JOUR T1 - Efficacy of rHVT-AI vector vaccine in broilers with passive immunity against challenge with two antigenically divergent Egyptian clade 2.2.1 HPAI H5N1 strains. JF - Avian Dis Y1 - 2012 A1 - Fabienne Rauw A1 - Palya, V A1 - Gardin, Y A1 - Tatar-Kis, T A1 - Dorsey, K Moore A1 - Bénédicte Lambrecht A1 - Thierry van den Berg KW - Animals KW - Antibodies, Viral KW - Antigens, Viral KW - Chickens KW - Gastrointestinal Tract KW - Immunity, Maternally-Acquired KW - Immunization, Secondary KW - Immunoglobulins KW - Influenza A Virus, H5N1 Subtype KW - Influenza in Birds KW - Influenza Vaccines KW - Vaccines, Inactivated AB -

In countries where avian influenza has become endemic, early vaccination of layer pullets or broilers with classical inactivated vaccines at the hatchery is no longer an option because of interference with passive immunity indirectly induced by the necessary vaccination of the breeders. On the other hand, injection of thousands of chicks from 7 to 10 days old on farms has been determined to be unreliable and, therefore, poorly efficacious. For these reasons, interest has arisen regarding a newly developed live recombinant vector vaccine based on a turkey herpesvirus (HVT) expressing the H5 gene from a clade 2.2 H5N1 highly pathogenic avian influenza virus (HPAIV) strain (rHVT-H5), which in theory is capable of breakthrough passive immunity to both the vector (HVT) and the insert (H5) and is consequently applicable at the hatchery. The objectives of this trial were to evaluate the impact of maternally derived antibodies (MDAs) specific to H5N1 on the immunity and the efficacy (protection and virus shedding) of different vaccination programs including rHVT-H5 and inactivated H5N1 and H5N2 vaccines applied alone or in combination. Therefore, broilers carrying MDAs against both HVT and Asian H5N1 HPAIV were vaccinated on the first day of age with rHVT-H5, with or without boosting vaccination by an inactivated vaccine after 10 days. The different groups were challenged with two antigenically highly divergent Egyptian dade 2.2.1 H5N1 HPAIVs at 4 wk of age. Protection against challenge was compared with unvaccinated birds or vaccinated birds without MDAs. Between 70% and 90% clinical protection could be observed in the vaccinated groups possessing MDAs, indicating no or very low interference of MDAs with vaccination. Results regarding clinical protection, humoral, cell-mediated, and mucosal immunity, as well as re-excretion of challenge virus are presented and discussed.

VL - 56 CP - 4 Suppl U1 - http://www.ncbi.nlm.nih.gov/pubmed/23402112?dopt=Abstract M3 - 10.1637/10172-041012-Reg.1 ER - TY - JOUR T1 - Further evidence of antigenic drift and protective efficacy afforded by a recombinant HVT-H5 vaccine against challenge with two antigenically divergent Egyptian clade 2.2.1 HPAI H5N1 strains. JF - Vaccine Y1 - 2011 A1 - Fabienne Rauw A1 - Palya, V A1 - Steven Van Borm A1 - Sarah Welby A1 - Tatar-Kis, T A1 - Gardin, Y A1 - Dorsey, K Moore A1 - Aly, M M A1 - Hassan, M K A1 - Soliman, M A A1 - Bénédicte Lambrecht A1 - Thierry van den Berg KW - Animals KW - Antibodies, Viral KW - Chickens KW - Drug Carriers KW - Genetic Vectors KW - Hemagglutination Inhibition Tests KW - Hemagglutinin Glycoproteins, Influenza Virus KW - Herpesvirus 1, Meleagrid KW - Immunization, Secondary KW - Influenza A Virus, H5N1 Subtype KW - Influenza A Virus, H5N2 Subtype KW - Influenza in Birds KW - Influenza Vaccines KW - Vaccination KW - Vaccines, Inactivated KW - Vaccines, Synthetic AB -

In this study, we have compared the protection afforded by a recombinant turkey herpesvirus vaccine expressing the H5 gene from a clade 2.2 H5N1 strain (rHVT-H5) and a Mexican-origin H5N2 inactivated vaccine, alone or in combination, against two antigenically divergent H5N1 Egyptian strains isolated in 2007 and 2008. Our results confirm the existence of a major antigenic drift among the Egyptian H5N1 strains such that, although protection against the "classical" 2007 HPAI H5N1 Egyptian strain could be obtained with both types of vaccines, only vaccination with the rHVT-H5 vaccine protected against challenge with the "variant" 2008 HPAI H5N1 Egyptian strain.

VL - 29 CP - 14 U1 - https://www.ncbi.nlm.nih.gov/pubmed/21292007?dopt=Abstract M3 - 10.1016/j.vaccine.2011.01.048 ER - TY - JOUR T1 - Measurement of systemic and local respiratory cell-mediated immunity after influenza infection in chickens. JF - Vet Immunol Immunopathol Y1 - 2011 A1 - Fabienne Rauw A1 - Anbari, Sofia A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Animals KW - Antigens, Viral KW - Chickens KW - Immunity, Cellular KW - Immunity, Mucosal KW - In Vitro Techniques KW - Influenza A Virus, H5N2 Subtype KW - Influenza in Birds KW - Interferons KW - Lung KW - Lymphocyte Activation KW - Spleen KW - T-Lymphocytes KW - Trachea AB -

The detection of ChIFN production after ex vivo antigenic-stimulation of T-lymphocytes has been evaluated for the first time, as a tool to assess cell-mediated immunity (CMI) after avian influenza (AI) infection in 10-day-old SPF chickens. Preliminarily, recall antigens have been produced either by concentrating and inactivating the whole virus or by dissociating the viral proteins. Biologically and structurally intact forms of the viral proteins were isolated by non-ionic detergents while heating, chemical agents and ionic detergent used for virus inactivation altered the antigenic viral components. The n-octyl-B-D-gluco-pyranoside treatment at low temperature was very efficient to produce AI antigenic proteins used for evaluation of ChIFN production after ex vivo antigenic-stimulation of splenic and peripheral lymphocytes. In addition, protocols to isolate lymphocytes from the respiratory tract - the trachea and the lung - have been adapted for local CMI evaluation after similar ex vivo recall assay. Specific AI CMI in the spleen, the blood and the lung was detected for 5 weeks after low pathogenic AI (LPAI) infection in chickens, while further development is needed for tracheal CMI measurement.

VL - 143 CP - 1-2 U1 - http://www.ncbi.nlm.nih.gov/pubmed/21696832?dopt=Abstract M3 - 10.1016/j.vetimm.2011.05.029 ER - TY - JOUR T1 - Improved vaccination against Newcastle disease by an in ovo recombinant HVT-ND combined with an adjuvanted live vaccine at day-old. JF - Vaccine Y1 - 2010 A1 - Fabienne Rauw A1 - Gardin, Yannick A1 - Palya, Vilmos A1 - Anbari, Sofia A1 - Lemaire, Sophie A1 - Boschmans, Marc A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Adjuvants, Immunologic KW - Administration, Intranasal KW - Animals KW - Antibodies, Viral KW - Chickens KW - Chitosan KW - Cloaca KW - Genetic Vectors KW - Herpesvirus 1, Meleagrid KW - Newcastle Disease KW - Ovum KW - Spleen KW - Survival Analysis KW - T-Lymphocytes KW - Vaccination KW - Vaccines, Attenuated KW - Vaccines, Synthetic KW - Viral Fusion Proteins KW - Viral Vaccines KW - Virus Shedding AB -

The continuous outbreaks of fatal Newcastle disease (ND) in commercial poultry flocks demonstrate that current vaccination strategies are not fully efficacious and should be improved by new generation of vaccines. In this context, maternally immune conventional layer chickens were vaccinated in ovo with a turkey herpesvirus recombinant expressing the fusion (F) gene of NDV (rHVT-ND) and/or at day-old with an apathogenic enterotropic live ND vaccine co-administrated or not with chitosan by oculo-nasal route. The induced vaccinal immune responses and conferred protection against a challenge with a circulating NDV velogenic viscerotropic strain were evaluated. The innovative rHVT-ND/live ND-chitosan vaccination regimen provided the best protection against mortality and morbidity as well as the strongest reduction of virus shedding that could be related to the higher measured cellular immune response and digestive antibody-mediated immunity.

VL - 28 CP - 3 U1 - http://www.ncbi.nlm.nih.gov/pubmed/19879230?dopt=Abstract M3 - 10.1016/j.vaccine.2009.10.049 ER - TY - JOUR T1 - The positive adjuvant effect of chitosan on antigen-specific cell-mediated immunity after chickens vaccination with live Newcastle disease vaccine. JF - Vet Immunol Immunopathol Y1 - 2010 A1 - Fabienne Rauw A1 - Gardin, Yannick A1 - Palya, Vilmos A1 - Anbari, Sofia A1 - Gonze, Martine A1 - Lemaire, Sophie A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Adjuvants, Immunologic KW - Animals KW - Chickens KW - Chitosan KW - Duodenum KW - Humans KW - Immunity, Cellular KW - Immunity, Humoral KW - Lymphocytes KW - mice KW - Newcastle Disease KW - Newcastle disease virus KW - Spleen KW - Viral Vaccines AB -

The development of safe, novel strong adjuvants is necessary to maximize the efficacy of and the immune response induced by new and/or available vaccines administered through the mucosal route to chickens. Chitosan is a non-toxic, biocompatible, biodegradable and natural polysaccharide derived from the exoskeleton of crustaceans and insects. It has been demonstrated to be an effective absorption enhancer to improve mucosal delivery of peptide and protein drugs in human and mice. In poultry, mucosal administration of live vaccine has been already explored with success. However, the effects of the use of the chitosan as adjuvant for mucosal vaccination in birds have not been investigated yet. To this aim, we explored its potential as adjuvant given by oculo-nasal route to one-day-old chickens with live Newcastle disease (ND) vaccine. The immune response has been evaluated during three independent vaccination experiments on specific pathogen free (SPF) chickens. It was shown that chitosan enhanced the antigen-specific cell-mediated immune response in the spleen. New protocols were developed to measure the chicken IFNgamma production after ex vivo antigen-stimulation of peripheral blood and duodenal lamina propria lymphocytes. It was then observed than the peripheral cellular immune response was earlier and stronger, while the local cellular immune response in digestive tract as shorter when chitosan was used as adjuvant. On the other hand, the chitosan had no effect on the systemic, lachrymal and digestive antibody-mediated immunity. This study indicates thus that the chitosan is a cell-promising adjuvant for the mucosal delivery of live vaccine in poultry, by enhancing the Th1 pathway of immunity. However, further investigations are required to explore its mechanism of action and to evaluate the inferred protection.

VL - 134 CP - 3-4 U1 - http://www.ncbi.nlm.nih.gov/pubmed/19939464?dopt=Abstract M3 - 10.1016/j.vetimm.2009.10.028 ER - TY - JOUR T1 - Humoral, cell-mediated and mucosal immunity induced by oculo-nasal vaccination of one-day-old SPF and conventional layer chicks with two different live Newcastle disease vaccines. JF - Vaccine Y1 - 2009 A1 - Fabienne Rauw A1 - Gardin, Yannick A1 - Palya, Vilmos A1 - Steven Van Borm A1 - Gonze, Martine A1 - Lemaire, Sophie A1 - Thierry van den Berg A1 - Bénédicte Lambrecht KW - Administration, Intranasal KW - Animals KW - Antibodies, Viral KW - Bile KW - Chickens KW - Duodenum KW - Eye KW - Immunity, Cellular KW - Immunity, Mucosal KW - Lung KW - Newcastle disease virus KW - Specific Pathogen-Free Organisms KW - Vaccination KW - Viral Vaccines AB -

To further characterize the immune response elicited by two live Newcastle disease vaccines, humoral, cellular and mucosal immunity was evaluated after oculo-nasal vaccination of day-old chickens. The preferential replication sites for each vaccine strain were investigated by screening different tissues using quantitative real-time reverse transcription-polymerase chain reaction (QRRT-PCR). The interference of maternally derived antibody with vaccination was also considered in conventional layer chickens. In SPF chickens, similar humoral immune-response was measured in blood and tears but a differential profile of cell-mediated immunity was observed according to the vaccine strain. The lung-associated humoral immunity was higher with the tracheotropic strain while the enterotropic vaccine induced a more important specific immunity in the digestive tract. The presence of maternally derived antibody in conventional layer chickens limited, if not completely abrogated, their immune responses to vaccination. This study increases our understanding of the protective immune response against Newcastle disease virus (NDV) and provides new useful informations for the development and evaluation of new types of vaccines.

VL - 27 CP - 27 U1 - https://www.ncbi.nlm.nih.gov/pubmed/19464544?dopt=Abstract M3 - 10.1016/j.vaccine.2009.03.068 ER - TY - JOUR T1 - Kinetic and biologic properties of recombinant ChIFN-gamma expressed via CELO-virus vector. JF - J Interferon Cytokine Res Y1 - 2007 A1 - Fabienne Rauw A1 - Bénédicte Lambrecht A1 - François, Achille A1 - Langlois, Patrick A1 - Thierry van den Berg KW - Animals KW - Antiviral Agents KW - Cell Line, Tumor KW - Chick Embryo KW - Fowl adenovirus A KW - Gene Expression KW - Interferon-gamma KW - Kinetics KW - Recombinant Proteins AB -

In this study, a replicative fowl adenovirus serotype 1 (CELO) recombinant expressing chicken interferon-gamma (ChIFN-gamma) was constructed. In the engineered recombinant, the ChIFN-gamma gene was placed under the control of cytomegalovirus (CMV) promoter. The ChIFN-gamma expression cassette was inserted in the right end of the CELO genome (D fragment), which was able to carry the largest insertion of foreign DNA without affecting the replication functions of the vector. The recombinant ChIFN-gamma (rChIFN-gamma) produced in the CELO-virus expression system was characterized by comparing its biologic activities with that of rChIFN-gamma produced via the baculovirus expression system (Bac-ChIFN-gamma). CELO-ChIFN-gamma inhibited the replication of cytolytic virus in chicken embryo fibroblasts (CEFs) and activated macrophages in a better manner than did Bac-ChIFN-gamma . Moreover, the in vitro and in vivo stability of the CELO-derived rChIFN-gamma was considerably higher than that of the Bac-ChIFN-gamma. The CELO-ChIFN-gamma recombinant vector was able to replicate in vitro in the loghorn male hepatoma (LMH) hepatocyte cell line and to produce detectable levels of recombinant cytokine in supernatant as early as 90 min post-infection. Therefore, the CELO-virus expression system is an appropriate system for high-level expression of biologically active and stable ChIFN-gamma.

VL - 27 CP - 2 U1 - http://www.ncbi.nlm.nih.gov/pubmed/17316138?dopt=Abstract M3 - 10.1089/jir.2006.0097 ER - TY - JOUR T1 - Pivotal role of ChIFNgamma in the pathogenesis and immunosuppression of infectious bursal disease. JF - Avian Pathol Y1 - 2007 A1 - Fabienne Rauw A1 - Bénédicte Lambrecht A1 - Thierry van den Berg KW - Animals KW - Birnaviridae Infections KW - Bursa of Fabricius KW - Cells, Cultured KW - Chickens KW - Immunosuppression KW - Infectious bursal disease virus KW - Interferon-gamma KW - Lymphocytes KW - Mitogens KW - Poultry Diseases KW - Specific Pathogen-Free Organisms KW - Spleen AB -

This study investigates the pivotal role of chicken interferon-gamma (ChIFNgamma) in the pathogenesis and immunosuppression of infectious bursal disease virus (IBDV) infection and is divided into in vivo, ex vivo and in vitro experiments. Two-week-old specific pathogen free chickens were inoculated with the 849VB very virulent strain of IBDV. The levels of systemic ChIFNgamma and chicken interleukin-6 in the serum were followed for 2 weeks during in vivo experiments. Then, splenocytes and bursal cells from infected chickens were analysed for their immunocompetence after mitogenic activation in ex vivo experiments. Finally, in vitro experiments were conducted to assess the direct immunosuppressive effect of ChIFNgamma on splenocytes and peripheral blood lymphocytes from non-inoculated specific pathogen free chickens. Our results reveal that the acute phase of infectious bursal disease coincides, on one hand, with high levels of systemic ChIFNgamma and chicken interleukin-6 and, on the other hand, with a strong inhibition of proliferation and activation of mitogen-stimulated splenocytes from infected chickens, as measured by ChIFNgamma production. Two weeks after viral inoculation, T lymphocytes infiltrating the bursa of Fabricius had recovered their activation capability. Finally, an in vitro study showed that the proliferation of naïve splenocytes and peripheral blood lymphocytes was directly and specifically inhibited by ChIFNgamma. In conclusion, a ChIFNgamma dysregulation occurs in chickens infected with IBDV and the overproduction of ChIFNgamma by T lymphocytes plays a key role in the pathogenesis and immunosuppression induced by this virus.

VL - 36 CP - 5 U1 - http://www.ncbi.nlm.nih.gov/pubmed/17899460?dopt=Abstract M3 - 10.1080/03079450701589159 ER - TY - Generic T1 - Belgische H3N1 Epizoötie Y1 - 0 A1 - Mieke Steensels A1 - Philippe Lagacé-Wiens A1 - Thierry van den Berg A1 - Steven Van Borm A1 - David Fretin A1 - Virginie Roupie A1 - Fabienne Rauw A1 - Bénédicte Lambrecht KW - 2019 KW - Avian Influenza KW - H3N1 AB -

Vanaf begin april (week 14) tot op 24.07.2019 (week 29), werden 82 bedrijven positief H3-AI gedetecteerd. Bij de getroffen bedrijven bevinden zich zowel verschillende types van bedrijven als verschillende species, verspreid in de tijd. De getroffen bedrijven bevinden zich voornamelijk in een beperkte geografische regio in het noordwesten van het land.

De karakterisatie van het virus wijst op een typisch laag pathogeen virus dat niet meldingsplichtig is volgens de EU-richtlijnen. De genetische informatie wijst op een oorsprong vanuit in wilde vogel circulerende AI virussen, met een aanpassing aan pluimvee ten gevolge van circulatie. In vivo experimenten in jonge SPF leggers bevestigden dit laag pathogeen pathotype. Bij leggers in productie zijn de klinische verschijnselen in het veld problematisch. Een infectie van AI-vrije conventionele leggers uit het veld toonden een eerder beperkte sterfte van 2/6 dieren één week na infectie, zonder sterfte bij de 6 contactdieren, en dit tijdens een 21 dagen studieduur.

ER - TY - Generic T1 - Epizootie H3N1 en Belgique Y1 - 0 A1 - Mieke Steensels A1 - Philippe Lagacé-Wiens A1 - Thierry van den Berg A1 - Steven Van Borm A1 - David Fretin A1 - Virginie Roupie A1 - Fabienne Rauw A1 - Bénédicte Lambrecht AB -

Depuis début avril (semaine 14) jusqu’au 4.07.2019 (semaine 29), 82 exploitations ont été détectées positive H3. Le secteur a été fortement impacté, tant les différents types d’élevages qu’une variété d’espèces ont été touchés dans cette période.  La majorité des élevages infectés étaient localisés dans une région limitée au nord-ouest du pays.

La caractérisation du virus a identificié un influenza aviaire faiblement pathogène, non notifiable conformémént aux directives de l’EU. Les informations génétiques indiquent une origine de virus de l'IA circulant chez les oiseaux sauvages, avec une adaptation à la volaille due à la circulation. Des expériences in vivo sur de jeunes poules pondeuses SPF ont confirmé ce pathotype faiblement pathogène. Par contre, les signes cliniques sur le terrain étaient surtout problématiques pour des pondeuses en production. Une infection des poules pondeuses conventionnelles terrain, confirmé négatif d'IA, a démontré une mortalité plutôt limitée de 2/6 animaux une semaine après l'infection, sans mortalité chez les 6 animaux de contact, et ceci pendant une période d'étude de 21 jours.

ER -