- I am Doctor in Veterinary Medicine graduated in 1966 at the University of Veterinary Science, Budapest, Hungary. In 1... moreI am Doctor in Veterinary Medicine graduated in 1966 at the University of Veterinary Science, Budapest, Hungary. In 1973 I obtained a Post-graduate diploma in Microbiology and Diseases of Cattle at the same University. In 2007 I was recognized as Honorary Professor by the Faculty of Veterinary Science of St. Steve University of Agriculture, Hungary. In recognition of my contribution in the furtherance of poultry veterinary science, the World Veterinary Poultry Association at their Congress in Edinburgh, Scotland, 2017 inducted me to be member of the “Hall of Honour”. I have extensive experience at various positions related to laboratory management and animal diseases control over a 50 years career. I was working more than 30 years in the field of poultry diseases diagnostics. I have substantial experience in setting up diagnostic laboratories in Europe, Asia and Africa, and training professional staff in laboratory techniques and disease control methods. I have performed extensive research and made several publications on IBD, ND, AI, IB, fowl adenoviruses (IBH), avian reoviruses and waterfowl parvoviruses. During the last two decades I have been working primarily in the field of vaccinology to improve conventional vaccines, developing and testing new generation vaccines (recombinant HVT-IBD, HVT-ND and HVT-AI) for the control of major viral poultry diseases. During the 80’s and 90’s I was working as UN/FAO vaccine expert in several African, Middle East and Asian countries to support global and national disease control/eradication programmes (e.g., Rinderpest, CBPP, Newcastle disease).Present position: Scientific adviser, Ceva-Phylaxia Veterinary Biologicals Co., Szallas u.5., 1107-Budapest, Hungary.I have published over 150 peer reviewed articles, giving numerous presentations and preparing consultancy reports. I wrote the section on Parvovirus Infections of Waterfowl in the 13th edition of Diseases of Poultry.Membership of professional bodies: Hungarian Society of Veterinarian (Poultry Diseases Section), Hungarian Society of Microbiology, World Veterinary Poultry Association, American Association of Avian Pathologists, Society of General Microbiology, International Association of Biological Standardization.edit
Background: Actinobacillus pleuropneumoniae is a major economically significant bacterial respiratory pathogen of pigs, and vaccine use is considered an integral control method to prevent disease. The objective of this multi-study... more
Background: Actinobacillus pleuropneumoniae is a major economically significant bacterial respiratory pathogen of pigs, and vaccine use is considered an integral control method to prevent disease. The objective of this multi-study analysis was to evaluate the serovar independent efficacy in growing pigs of the C-vaccine (Coglapix®, Ceva, France), which comprises whole cells of A. pleuropneumoniae serovars 1 and 2 expressing ApxI, ApxII and ApxIII toxins. Efficacy was based on protection against lung lesions, since there is good correlation between the severity/extension of lung lesions and losses induced by pleuropneumonia. Vaccine efficacy was determined against challenge with the most common serovars (1, 2, 4, 5, 6, 7, 9/11 and 13) of A. pleuropneumoniae in a total of 13 studies of the same design and reproducibility was validated.Results: Protection against homologous serovars 1 and 2 significantly reduced lung lesion scores (LLS) compared to the positive controls: p = 0.00007 an...
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Research Interests: Genetics, Biology, Medicine, Genetic Diversity, Biological Sciences, and 15 moreDisease Outbreaks, Europe, Hungary, Animals, Chickens, Genetic variation, Monoclonal Antibody, Amino Acid Sequence, Genetic Similarity, Antigenic Variation, Molecular Sequence Data, Nucleotide sequence, Infectious bursal disease virus, Chick embryo, and Medical and Health Sciences
SUMMARY. The most recent pandemic clade of highly pathogenic avian influenza (HPAI) H5, clade 2.3.4.4, spread widely, with the involvement of wild birds, most importantly wild waterfowl, carrying the virus (even asymptomatically) from... more
SUMMARY. The most recent pandemic clade of highly pathogenic avian influenza (HPAI) H5, clade 2.3.4.4, spread widely, with the involvement of wild birds, most importantly wild waterfowl, carrying the virus (even asymptomatically) from Asia to North America, Europe, and Africa. Domestic waterfowl being in regular contact with wild birds played a significant role in the H5Nx epizootics. Therefore, protection of domestic waterfowl from H5Nx avian influenza infection would likely cut the transmission chain of these viruses and greatly enhance efforts to control and prevent disease outbreak in other poultry and animal species, as well as infection of humans. The expectation for such a vaccine is not only to provide clinical protection, but also to control challenge virus transmission efficiently and ensure that the ability to differentiate infected from vaccinated animals is retained. A water-in-oil emulsion virus-like particle vaccine, containing homologous hemagglutinin antigen to the current European H5N8 field strains, has been developed to meet these requirements. The vaccine was tested in commercial Pekin and mule ducks by vaccinating them either once, at 3 wk of age, or twice (at 1 day and at 3 wk of age). Challenge was performed at 6 wk of age with a Hungarian HPAIV H5N8 isolate (2.3.4.4 Group B). Efficacy of vaccination was evaluated on the basis of clinical signs, amount of virus shedding, and transmission. Vaccination resulted in complete clinical protection and prevention of challenge virus transmission from the directly challenged vaccinated ducks to the vaccinated contact animals.
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To investigate the immunogenic cross reactivity between goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV), cross-neutralization was carried out with serum samples collected from birds after infection with one of the two waterfowl... more
To investigate the immunogenic cross reactivity between goose parvovirus (GPV) and Muscovy duck parvovirus (MDPV), cross-neutralization was carried out with serum samples collected from birds after infection with one of the two waterfowl parvoviruses. The significantly higher virus neutralization titer obtained against the homologous virus than against the heterologous one suggests important differences between the GPV and MDPV antigenic make up that affects the induced protective virus-neutralizing antibody specificity. This was further confirmed by cross-protection studies carried out in waterfowl parvovirus antibody-free Muscovy ducks immunized at one day of age with whole-virus inactivated oil-emulsion vaccines containing either GPV or MDPV as a monovalent vaccine, or both viruses as a bivalent vaccine. Protection against the clinical disease (growth retardation and feathering disorders) provided by the monovalent vaccine was complete against homologous virus challenge at 2 week...
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Waterfowl play a key role in the epidemiology of the H5N1 subtype of highly pathogenic avian influenza (HPAI) virus, therefore efficient immunization of domesticated ducks and geese to maximize the impact of other control measures is of... more
Waterfowl play a key role in the epidemiology of the H5N1 subtype of highly pathogenic avian influenza (HPAI) virus, therefore efficient immunization of domesticated ducks and geese to maximize the impact of other control measures is of great importance. Previous studies have shown that herpesvirus of turkey (HVT) is able to replicate in certain species of waterfowl. A recombinant HVT-AI vaccine (rHVT-AI), expressing the HA gene of a clade 2.2 H5N1 HPAIV strain had been developed and proved to be efficient against different clades of H5N1 HPAIV in chickens after a single vaccination at day-old and could provide long-term immunity. In the study presented here we investigated if rHVT-AI is able to replicate in different species and cross-breeds of ducks and in geese with the aim of collecting data on the possible application of rHVT-AI vaccine in different species of waterfowl for the control of H5N1 HPAI. In the studies conducted we tested the possible differences among different wat...
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Avian infectious bronchitis (IB) is among the major viral respiratory and reproductive diseases of chickens caused by Avian coronavirus. In the African continent, IB was first described in countries located in the Mediterranean basin. In... more
Avian infectious bronchitis (IB) is among the major viral respiratory and reproductive diseases of chickens caused by Avian coronavirus. In the African continent, IB was first described in countries located in the Mediterranean basin. In other parts of the continent, the epidemiological situation of IB remains unclear. In this study, the complete genome sequences of five IBV strains, originating from the sub-Saharan area were determined. Phylogenetic analysis based on the full-length S1 sequences identified three lineages (GI-14, GI-16, and GI-19) common in Africa and revealed that a strain, D2334/11/2/13/CI, isolated in Ivory Coast may represent a novel lineage within genotype GI. The maximum inter- and intragenotype sequence identities between this strain and other IBVs were 67.58% and 78.84% (nucleotide) and 64.44% and 78.6% (amino acid), respectively. The whole-genome nucleotide identity of the novel variant shared the highest values with a reference Belgian nephropathogenic str...
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We determined the genomic sequence of a Ukrainian strain of fowl adenovirus B (FAdV-B). The isolate (D2453/1) shared 97.2% to 98.4% nucleotide sequence identity with other viruses belonging to the species Fowl aviadenovirus B. Marked... more
We determined the genomic sequence of a Ukrainian strain of fowl adenovirus B (FAdV-B). The isolate (D2453/1) shared 97.2% to 98.4% nucleotide sequence identity with other viruses belonging to the species Fowl aviadenovirus B. Marked genetic divergence was seen in the hexon, fiber, and ORF19 genes, and phylogenetic analysis suggested that recombination events had occurred in these regions. Our analysis revealed mosaicism in the recombination patterns, a finding that has also been described in the genomes of strains of FAdV-D and FAdV-E. The shared recombination breakpoints, affecting the same genomic regions in viruses belonging to different species, suggest that similar selection mechanisms are acting on the key neutralization antigens and epitopes in viruses of different FAdV species. Supplementary Information The online version contains supplementary material available at 10.1007/s00705-021-04972-9.
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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,... more
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,...
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Research Interests: Microbiology, Mass Spectrometry, Biology, Medicine, Cell line, and 15 moreEurope, Avian Pathology, Animals, Polymerase Chain Reaction, Geese, POULTRY DISEASES, In vitro culture, Avian, Veterinary Sciences, Polyomavirus, Amino Acid Sequence, Mortality rate, Spodoptera litura, Molecular Sequence Data, and Nephritis
Research Interests: Microbiology, Biology, Transmission Electron Microscopy, Medicine, Cercopithecus aethiops, and 15 moreDisease Outbreaks, Brain, Avian Pathology, Hungary, Animals, Geese, Degeneration, Age Factors, Veterinary Sciences, Base Sequence, Vero cells, Molecular Sequence Data, Cloaca, reverse transcriptase polymerase chain reaction, and Bird diseases
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Duck hepatitis A virus (DHAV), an avian picornavirus, causes high-mortality acute disease in ducklings. Among the three serotypes, DHAV-1 is globally distributed, whereas DHAV-2 and DHAV-3 serotypes are chiefly restricted to Southeast... more
Duck hepatitis A virus (DHAV), an avian picornavirus, causes high-mortality acute disease in ducklings. Among the three serotypes, DHAV-1 is globally distributed, whereas DHAV-2 and DHAV-3 serotypes are chiefly restricted to Southeast Asia. In this study, we analyzed the genomic evolution of DHAV-1 strains using extant GenBank records and genomic sequences of 10 DHAV-1 strains originating from a large disease outbreak in 2004–2005, in Hungary. Recombination analysis revealed intragenotype recombination within DHAV-1 as well as intergenotype recombination events involving DHAV-1 and DHAV-3 strains. The intergenotype recombination occurred in the VP0 region. Diversifying selection seems to act at sites of certain genomic regions. Calculations estimated slightly lower rates of evolution of DHAV-1 (mean rates for individual protein coding regions, 5.6286 × 10−4 to 1.1147 × 10−3 substitutions per site per year) compared to other picornaviruses. The observed evolutionary mechanisms indica...
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Avian reoviruses are well-known pathogens seriously affecting the productivity of poultry industry. Game birds represent a small segment of the agricultural sector and much remained to be learnt about factors affecting productivity. Here... more
Avian reoviruses are well-known pathogens seriously affecting the productivity of poultry industry. Game birds represent a small segment of the agricultural sector and much remained to be learnt about factors affecting productivity. Here we show that reovirus infections might occur in pheasants and demonstrate that reoviruses of pheasants are of diverse origin. The complete or coding-complete genomic sequences of two Hungarian reovirus strains, D1996/2/1 and Reo/HUN/Pheasant/216/2015, have been determined in this study. The strain D1996/2/1 was isolated in 2012 from birds with gizzard erosion, whereas the other strain was isolated in 2015 from diarrheic pheasant poults. Phylogenetic analyses showed that none of the Hungarian isolates shared common origin with a pheasant reovirus detected recently in the United States. Additionally, we found that Reo/HUN/Pheasant/216/2015 is a multi-reassortant reovirus within the species Avian orthoreovirus that shared genetic relationship with turk...
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SUMMARY. From October 2016 to July 2017, 47 countries have been affected by highly pathogenic avian influenza (HPAI) viruses of the H5N8 clade 2.3.4.4 subtype, including European and African, and it has been the most severe HPAI outbreak... more
SUMMARY. From October 2016 to July 2017, 47 countries have been affected by highly pathogenic avian influenza (HPAI) viruses of the H5N8 clade 2.3.4.4 subtype, including European and African, and it has been the most severe HPAI outbreak ever in Europe. The development of effective influenza vaccines is required to combine preventive and control measures in order to avoid similar avian influenza epidemics taking place. Here we describe a novel prototype recombinant virus-like particle (VLP) vaccine based on a clade 2.3.4.4 H5 HA derived from a French duck HPAI H5N8 isolate of the 2016–2017 epidemics. Prototype vaccines with different antigen content were formulated and the immunogenicity was examined in specific-pathogen-free chickens and in ducks. Serum samples were collected at 3 and 4 weeks postvaccination, and development of the immune response was evaluated by hemagglutination inhibition test and ELISA. The VLP vaccines induced a dose-dependent and high level of antibody response in both chickens and ducks. The results of HPAI H5N8 challenge experiments in ducks are reported separately.
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To the Editor: We would like to retract our article Novel Orthobunyavirus Causing Severe Kidney Disease in Broiler Chickens, Malaysia, 2014–2017 from the June 2019 issue of Emerging Infectious Diseases (1). We assert that research was... more
To the Editor: We would like to retract our article Novel Orthobunyavirus Causing Severe Kidney Disease in Broiler Chickens, Malaysia, 2014–2017 from the June 2019 issue of Emerging Infectious Diseases (1). We assert that research was performed in good faith, that all the experimental data contained in the article are well founded and scientifically valid, and that there was no scientific misconduct. However, we subsequently were made aware of further information about the epidemiologic and clinical observations made locally in Malaysia, which brings into question the geographic location where the noted virus originated. Thus, we request this article’s retraction.
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Newcastle Disease is one of the most important infectious poultry diseases worldwide and is associated with high morbidity, mortality, and economic loss. In several countries, vaccination is applied to prevent and control outbreaks;... more
Newcastle Disease is one of the most important infectious poultry diseases worldwide and is associated with high morbidity, mortality, and economic loss. In several countries, vaccination is applied to prevent and control outbreaks; however, information on the ability of vaccines to reduce transmission of ND virus (NDV) is sparse. Here we quantified the transmission of velogenic NDV among 42-day-old broilers. Chickens were either vaccinated with a single dose of a vector vaccine expressing the F protein (rHVT-ND) at day-old in the presence of maternally derived antibodies or kept unvaccinated. Seeders were challenged 8 h before the co-mingling with the corresponding contacts from the same group. Infection was monitored by daily testing of cloacal and oro-nasal swabs with reverse transcription-real-time PCR and by serology. Vaccinated birds were completely protected against clinical disease and virus excretion was significantly reduced compared to the unvaccinated controls that all d...
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Infectious bronchitis of chicken is a high morbidity and mortality viral disease affecting the poultry industry worldwide; therefore, a better understanding of this pathogen is of utmost importance. The primary aim of this study was to... more
Infectious bronchitis of chicken is a high morbidity and mortality viral disease affecting the poultry industry worldwide; therefore, a better understanding of this pathogen is of utmost importance. The primary aim of this study was to obtain a deeper insight into the genomic diversity of field infectious bronchitis virus (IBV) strains using phylogenetic and recombination analysis. We sequenced the genome of 20 randomly selected strains from seven European countries. After sequencing, we created a genome sequence data set that contained 36 European origin field isolates and 33 vaccine strains. When analyzing these 69 IBV genome sequences, we identified 215 recombination events highlighting that some strains had multiple recombination breaking points. Recombination hot spots were identified mostly in the regions coding for non-structural proteins, and multiple recombination hot spots were identified in the nsp2, nsp3, nsp8, and nsp12 coding regions. Recombination occurred among diffe...
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The control of Newcastle disease (ND) highly relies on vaccination. Immunity provided by a ND vaccine can be characterized by measuring the level of clinical protection and reduction in challenge virus shedding. The extent of shedding... more
The control of Newcastle disease (ND) highly relies on vaccination. Immunity provided by a ND vaccine can be characterized by measuring the level of clinical protection and reduction in challenge virus shedding. The extent of shedding depends a lot on the characteristics of vaccine used and the quality of vaccination, but influenced also by the genotype of the challenge virus. We demonstrated that vaccination of SPF chicks with recombinant herpesvirus of turkey expressing the F-gene of genotype I ND virus (rHVT-ND) provided complete clinical protection against heterologous genotype VII.1.1 ND virus strain and reduced challenge virus shedding significantly. 100% of clinical protection was achieved already by 3 weeks of age, irrespective of the challenge route (intra-muscular or intra-nasal) and vaccination blocked cloacal shedding almost completely. Interestingly, oro-nasal shedding was different in the two challenge routes: less efficiently controlled following intra-nasal than intr...
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The recombinant herpesvirus of turkey (rHVT) vaccines targeting Newcastle disease (ND) and H5Nx avian influenza (AI) have been demonstrated efficient in chickens when used individually at day-old. Given the practical field constraints... more
The recombinant herpesvirus of turkey (rHVT) vaccines targeting Newcastle disease (ND) and H5Nx avian influenza (AI) have been demonstrated efficient in chickens when used individually at day-old. Given the practical field constraints associated with administering two vaccines separately and in the absence of a currently available bivalent rHVT vector vaccine expressing both F(ND) and H5(AI) antigens, the aim of this study was to investigate whether interference occurs between the two vaccines when simultaneously administered in a single shot. The studies have been designed to determine (i) the ND and AI-specific protection and antibody response conferred by these vaccines inoculated alone or in combination at day-old, (ii) the influence of maternally-derived antibodies (MDA), and (iii) the potential interference between the two vaccine. Our results demonstrate that their combined administration is efficient to protect chickens against clinical signs of velogenic Newcastle disease v...
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Outbreaks caused by the highly pathogenic avian influenza virus (HPAIV) H5N8 subtype clade 2.3.4.4 were first reported in 2014 in South Korea then spread very rapidly in Asia, to Europe, and for the first time, to North America. Efficacy... more
Outbreaks caused by the highly pathogenic avian influenza virus (HPAIV) H5N8 subtype clade 2.3.4.4 were first reported in 2014 in South Korea then spread very rapidly in Asia, to Europe, and for the first time, to North America. Efficacy of a recombinant HVT-AI (H5) vaccine (rHVT-H5) to provide clinical protection as well as to significantly reduce the shedding of an H5N8 challenge virus has already been demonstrated in SPF chickens. The aim of our studies was to test the efficacy of the same rHVT-H5 vaccine in controlling the transmission of a recent Hungarian HPAIV H5N8 challenge virus in commercial chickens. Broilers and layers were vaccinated at day old according to the manufacturer’s recommendation and then challenged with a 2017 Hungarian HPAIV H5N8 (2.3.4.4b) isolate at 5 or 7 weeks of age, respectively. Evaluation of clinical protection, reduction of challenge virus shedding, and transmission to vaccinated contact birds was done on the basis of clinical signs/mortality, dete...
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Complete genomic sequences of two orthoreovirus strains, D2533/4/1-10 and D2533/6/1-10, isolated from Pekin ducklings in Germany have been determined. Pairwise sequence comparisons and phylogenetic analyses indicated that strain... more
Complete genomic sequences of two orthoreovirus strains, D2533/4/1-10 and D2533/6/1-10, isolated from Pekin ducklings in Germany have been determined. Pairwise sequence comparisons and phylogenetic analyses indicated that strain D2533/4/1-10 might have acquired its genomic segments from three different origins, from classical and novel waterfowl reoviruses, and a yet unknown orthoreovirus strain. D2533/6/1-10 proved to be only distantly related to previously described orthoreoviruses. Reassortment, host species transmission events, and successful adaptation of novel variants may signify a challenge for animal health and maintenance of economic production.
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Newcastle disease (ND) is still a major poultry disease worldwide. Vaccination remains the principal method of controlling ND in endemic countries. Various vaccination strategies, including the use of recently developed recombinant... more
Newcastle disease (ND) is still a major poultry disease worldwide. Vaccination remains the principal method of controlling ND in endemic countries. Various vaccination strategies, including the use of recently developed recombinant vaccines, have been used to control it. Recombinant vaccines that use the herpesvirus of turkey (HVT) as a vector to express one of the key antigens of Newcastle disease virus (NDV) have been developed to overcome some of the drawbacks related to the use of conventional vaccines. HVT as a vector appears to have unique beneficial characteristics: it is extremely safe, it is not affected by the presence of maternally derived antibodies, and therefore can be applied in the hatchery either in ovo or to day-old chicks. Due to its persistence in the bird, the HVT vector can be expected to induce life-long immune stimulation. In the present study, the efficacy of an HVT-based vector vaccine expressing the F gene of NDV (rHVT-F) was tested against a velogenic gen...
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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.... more
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...