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Recombinase polymerase amplification-nucleic acid lateral flow immunoassays for Newcastle disease virus and infectious bronchitis virus detection. Mol Biol Rep 2019; 46:6391-6397. [PMID: 31549369 PMCID: PMC7089497 DOI: 10.1007/s11033-019-05085-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/18/2019] [Indexed: 12/15/2022]
Abstract
Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) are two poultry pathogens affecting the respiratory tract of chickens, and cause major economic losses in the industry. Rapid detection of these viruses is crucial to inform implementation of appropriate control measures. The objective of our study is developing a simple, rapid and field applicable recombinase polymerase amplification (RPA)–nucleic acid lateral flow (NALF) immunoassay for detection of NDV and IBV. Isothermal amplification of the matrix protein (M) gene of NDV and the nucleoprotein (N) gene of IBV was implemented via recombinase polymerase amplification at 38 °C for 40 min and 20 min, respectively using modified labeled primers. NALF device used in this study utilizes antibodies for detection of labeled RPA amplicons. The results revealed that RPA-NALF immunoassays can detect both viruses after 40 min at 38 °C and only NDV after 20 min. The limit of detection (LOD) was 10 genomic copies/RPA reaction. The assays results on clinical samples collected from diseased chicken farms demonstrated a good performance in comparison with quantitative real time reverse transcription polymerase chain reaction (qRT-PCR). The assays established in this study can facilitate rapid, on-site molecular diagnosis of suspected cases of ND and IB viral infections as the results can be detected by the naked eye without the need for measuring fluorescence. Furthermore, the NALF device could be adapted to detect other infectious agents.
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Aston EJ, Jackwood MW, Gogal RM, Hurley DJ, Fairchild BD, Hilt DA, Cheng S, Tensa LR, Garcia M, Jordan BJ. Ambient ammonia does not appear to inhibit the immune response to infectious bronchitis virus vaccination and protection from homologous challenge in broiler chickens. Vet Immunol Immunopathol 2019; 217:109932. [PMID: 31472338 DOI: 10.1016/j.vetimm.2019.109932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 08/16/2019] [Accepted: 08/22/2019] [Indexed: 12/12/2022]
Abstract
Commercial broilers are commonly exposed to gaseous ammonia (NH3) originating from degradation of nitrogen-containing excreta in the litter during the grow-out period. Ammonia concentrations in the air are higher in poorly ventilated houses and appear to coincide with the elevated incidence of respiratory disease occurring during the winter months. This study examined the effect of NH3 on the immune response to infectious bronchitis virus (IBV) vaccination and protection against homologous serotype challenge in commercial broiler chickens. One-day-old chicks were administered IBV vaccine and exposed to 30-60 ppm of NH3. At 28 DOA, birds were challenged oculonasally with a pathogenic homologous IBV, and protection was measured by viral detection, clinical signs, ciliostasis, and presence of airsacculitis. IBV-specific serum IgG and lacrimal fluid IgA titers, as well as Harderian gland (HG) immune cell phenotypes, were evaluated. Ammonia exposure was associated with an increased incidence of airsacculitis among non-vaccinated, challenged birds. Vaccinated, NH3-exposed birds were completely protected from IBV challenge. Ammonia had subtle effects on cilia morphology and function but did not affect vaccine or challenge virus replication and clearance, clinical signs, ciliostasis, tracheal histopathology scores, or immune responses. In the HG of vaccinated birds, the percent of leukocytes, MHC I+/MHC IIhi expression, IgM+ expression, and CD8+ expression was increased, while mucosal IgA and serum IgG titers were nominal. Non-vaccinated, IBV-challenged birds exhibited an increased percent of leukocytes, MHC I+/MHC IIhi expression, and IgM+ expression in the HG at 5 dpc, followed by increased mucosal IgA and serum IgG titers and CD8+ expression at 10-14 dpc. In contrast, vaccinated, IBV-challenged birds had a minimal increase in MHC I+/MHC IIhi expression, and serum IgG antibody titers in vaccinated birds increased rapidly. The results indicate that commercial broilers exposed to moderate levels of ambient NH3 are equally protected against IBV challenge if appropriately vaccinated, and the absence of robust immune activation in vaccinated, challenged birds suggests that the challenge virus was efficiently neutralized before establishing infection. In contrast, ambient NH3 exposure was associated with a higher incidence of airsacculitis in non-vaccinated, challenged birds, despite the apparent lack of differences in the immune response between birds in the NH3-exposed and NH3 control groups.
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Wu Q, Lin Z, Qian K, Shao H, Ye J, Qin A. Peptides with 16R in S2 protein showed broad reactions with sera against different types of infectious bronchitis viruses. Vet Microbiol 2019; 236:108391. [PMID: 31500728 PMCID: PMC7117385 DOI: 10.1016/j.vetmic.2019.108391] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 08/14/2019] [Accepted: 08/15/2019] [Indexed: 01/20/2023]
Abstract
We examined the specific amino acids contributing to S2 epitopes in IBVs. 16R in S2 protein was a key amino acid mediating the antigenicity of S2 protein. S2-derived peptides with 16R, but not those with 16 K, reacted with IBV-infected serum. Commercial ELISAs did not react with sera harboring all types of IBVs. S2-derived peptides with 16R could be novel antigens for anti-IBV vaccines.
Vaccination plays a vital role in controlling diseases caused by chicken infectious bronchitis virus (IBV). The continuously variant antigenicity of IBV limits the application of current vaccine strategies and serological diagnostic systems. S2 protein is an invariant that harbors broad neutralizing epitopes. However, little is known about the key amino acids that contribute to the broad-spectrum S2 epitopes. In this study, we aimed to elucidate the specific amino acids contributing to S2 epitopes. Site mutagenesis and peptide-based enzyme-linked immunosorbent assays (ELISAs) showed that 16R in S2 protein was a key amino acid mediating the antigenicity of S2 protein. S2-derived peptides with 16R, but not those with 16 K, could react with sera against different types of IBVs. Notably, a commercial ELISA kit for detection of antibodies against IBV did not react with sera against all types of IBVs. Taken together, these data demonstrated that S2-derived peptides with 16R could be used as novel marker-based antigens for developing both broad-spectrum vaccines and serological diagnostic kits to control IBV.
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Chacón RD, Astolfi-Ferreira CS, Chacón JL, Nuñez LFN, De la Torre DI, Piantino Ferreira AJ. A seminested RT-PCR for molecular genotyping of the Brazilian BR-I Infectious Bronchitis Virus Strain (GI-11). Mol Cell Probes 2019; 47:101426. [PMID: 31365883 DOI: 10.1016/j.mcp.2019.101426] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/17/2019] [Accepted: 07/25/2019] [Indexed: 10/26/2022]
Abstract
Infectious bronchitis (IB) is one of the avian diseases with the greatest impact on poultry farming worldwide. In Brazil, strain BR-I (GI-11) is the most prevalent in poultry flocks. The present study aimed to develop a seminested RT-PCR assay specific for the diagnosis of BR-I IBV in Brazilian samples, targeting subunit 1 of the S gene. The detection limit of this assay was 10 copies of the IBV genome. In this study, 62.24% of 572 organ pools from the 5 regions of Brazil tested positive in a 3'UTR screening, and 84.83% were typed as BR-I IBV. BR-I was detected in the respiratory, digestive and urogenital tracts in pooled samples from all Brazilian geographical regions and in all the breeding systems analyzed. Specificity and sensitivity tests as well as phylogenetic analysis successfully confirmed the expected clustering of the sequences detected by this assay with the BR-I (GI-11) group. The nested PCR described in this study represents a suitable and valuable tool in the diagnosis, epidemiology, monitoring and vaccination decisions of IBV.
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Fujisawa S, Murata S, Takehara M, Katakura K, Hmoon MM, Win SY, Ohashi K. Molecular detection and genetic characterization of Mycoplasma gallisepticum, Mycoplama synoviae, and infectious bronchitis virus in poultry in Myanmar. BMC Vet Res 2019; 15:261. [PMID: 31345206 PMCID: PMC6659308 DOI: 10.1186/s12917-019-2018-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/22/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In Southeast Asian countries, including Myanmar, poultry farming is a major industry. In order to manage and maintain stable productivity, it is important to establish policies for biosecurity. Infectious respiratory diseases are a major threat to poultry farming. Avian influenza and Newcastle disease have been reported in Myanmar, but no scientific information is available for other respiratory pathogens, such as mycoplasmas and infectious bronchitis virus (IBV). Identifying the genotypes and serotypes of IBVs is especially important to inform vaccination programs. In this study, we detected Mycoplasma gallisepticum (MG), M. synoviae (MS), and IBV in several poultry farms in Myanmar. RESULTS Samples were collected from 20 farms in three major poultry farming areas in Myanmar, and MG, MS, and IBV were detected on two, four, and eight farms, respectively, by polymerase chain reaction. Phylogenetic analysis revealed that the observed MG and MS isolates were not identical to vaccine strains. Three different genotypes of IBV were detected, but none was an unknown variant. CONCLUSIONS Mycoplasmas and IBV were detected on poultry farms in Myanmar. Periodic surveillance is required to establish the distribution of each pathogen, and to institute better vaccine protocols.
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Xiao Q, Yan L, Yao L, Lei J, Bi Z, Hu J, Chen Y, Fang A, Li H, Li Y, Yan Y, Zhou J. Development of oligonucleotide microarray for accurate and simultaneous detection of avian respiratory viral diseases. BMC Vet Res 2019; 15:253. [PMID: 31324180 PMCID: PMC6642548 DOI: 10.1186/s12917-019-1985-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/27/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Avian influenza virus (AIV), infectious bronchitis virus (IBV), and Newcastle disease virus (NDV) are important avian pathogens that can cause enormous economic loss on the poultry industry. Different respiratory etiological agents may induce similar clinical signs that make differential diagnosis difficult. Importantly, AIV brings about severe threat to human public health. Therefore, a novel method that can distinguish these viruses quickly and simultaneously is urgently needed. RESULTS In this study, an oligonucleotide microarray system was developed. AIV, including H5, H7, and H9 subtypes; NDV; and IBV were simultaneously detected and differentiated on a microarray. Three probes specific for AIV, NDV, and IBV, as well as three other probes for differentiating H5, H7, and H9 of AIV, were first designed and jet-printed to predetermined locations of initiator-integrated poly(dimethylsiloxane) for the synchronous detection of the six pathogens. The marked multiplex reverse transcription polymerase chain reaction (PCR) products were hybridized with the specific probes, and the results of hybridization were read directly with the naked eyes. No cross-reaction was observed with 10 other subtypes of AIV and infectious bursal disease virus, indicating that the oligonucleotide microarray assay was highly specific. The sensitivity of the method was at least 100 times higher than that of the conventional PCR, and the detection limit of NDV, AIV, H5, H7, and H9 can reach 0.1 EID50 (50% egg infective dose), except that of IBV, which was 1 EID50 per reaction. In the validation of 93 field samples, AIV, IBV, and NDV were detected in 53 (56.99%) samples by oligonucleotide microarray and virus isolation and in 50 (53.76%) samples by conventional PCR. CONCLUSIONS We have successfully developed an approach to differentiate AIV, NDV, IBV, H5, H7, and H9 subtypes of AIV using oligonucleotide microarray. The microarray is an accurate, high-throughput, and relatively simple method for the rapid detection of avian respiratory viral diseases. It can be used for the epidemiological surveillance and diagnosis of AIV, IBV, and NDV.
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Lin J, Wang Z, Wang J, Yang Q. Microarray analysis of infectious bronchitis virus infection of chicken primary dendritic cells. BMC Genomics 2019; 20:557. [PMID: 31286855 PMCID: PMC6615177 DOI: 10.1186/s12864-019-5940-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 06/26/2019] [Indexed: 02/07/2023] Open
Abstract
Background Avian infectious bronchitis virus (IBV) is a major respiratory disease-causing agent in birds that leads to significant losses. Dendritic cells (DCs) are specialised cells responsible for sampling antigens and presenting them to T cells, which also play an essential role in recognising and neutralising viruses. Recent studies have suggested that non-coding RNAs may regulate the functional program of DCs. Expression of host non-coding RNAs changes markedly during infectious bronchitis virus infection, but their role in regulating host immune function has not been explored. Here, microarrays of mRNAs, miRNAs, and lncRNAs were globally performed to analyse how avian DCs respond to IBV. Results First, we found that IBV stimulation did not enhance the maturation ability of avian DCs. Interestingly, inactivated IBV was better able than IBV to induce DC maturation and activate lymphocytes. We identified 1093 up-regulated and 845 down-regulated mRNAs in IBV-infected avian DCs. Gene Ontology analysis suggested that cellular macromolecule and protein location (GO-BP) and transcription factor binding (GO-MF) were abundant in IBV-stimulated avian DCs. Meanwhile, pathway analysis indicated that the oxidative phosphorylation and leukocyte transendothelial migration signalling pathways might be activated in the IBV group. Moreover, alteration of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) was detected in IBV-stimulated avian DCs. In total, 19 significantly altered (7 up and 12 down) miRNAs and 101 (75 up and 26 down) lncRNAs were identified in the IBV-treated group. Further analysis showed that the actin cytoskeleton and MAPK signal pathway were related to the target genes of IBV-stimulated miRNAs. Finally, our study identified 2 TF-microRNA and 53 TF–microRNA–mRNA interactions involving 1 TF, 2 miRNAs, and 53 mRNAs in IBV-stimulated avian DCs. Conclusions Our research suggests a new mechanism to explain why IBV actively blocks innate responses needed for inducing immune gene expression and also provides insight into the pathogenic mechanisms of avian IBV. Electronic supplementary material The online version of this article (10.1186/s12864-019-5940-6) contains supplementary material, which is available to authorized users.
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Molecular and biological characteristics of the infectious bronchitis virus TC07-2/GVI-1 lineage isolated in China. INFECTION GENETICS AND EVOLUTION 2019; 75:103942. [PMID: 31255833 PMCID: PMC7185777 DOI: 10.1016/j.meegid.2019.103942] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/22/2019] [Accepted: 06/25/2019] [Indexed: 01/21/2023]
Abstract
In the present study, a thorough comparison of the infectious bronchitis virus (IBV) TC07–2/GVI-1 linage was conducted by comparing the S1 gene sequences of GVI-1 viruses with those of viruses representing the established genotypes and lineages. IBV GVI-1 strains were found to be closely genetically related to each other, irrespective of where the viruses were isolated, and differed from other known IBV genotypes and lineages; thus, it was confirmed that GVI represents a novel genotype. However, the GVI-1 viruses exhibited variable antigenicity when compared to each other. Further analysis found that strains CO8089L and CO8091L, which were isolated in Colombia in 2003, were closely related to GVI-1 viruses, suggesting that GVI-1 viruses likely originated from Colombia and are prevalent in at least five countries (Colombia, China, the Republic of Korea, Japan, and Vietnam). Analysis of the complete GVI-1 virus genomes suggested that the GVI-1 strains in China may be independently derived from recombination events that occurred between GI-19 strains and CO8089L/CO8091L-like viruses following the introduction of the viruses from Colombia. Similar to the viruses isolated in the Republic of Korea, GVI-1 viruses isolated in China also showed an affinity for the respiratory tract of chickens, which differed from one of the deduced parental viruses, the GI-19 strain. This difference may be due to recombination events that occurred in the genomes of the GVI-1 viruses, resulting in the replacement of the spike gene sequences in an YX10-like strain of GI-19 lineage. GVI-1 viruses likely originated from Columbia. GVI-1 strains isolated in China may be derived from recombination events between GI-19 and CO8089L/CO8091L-like viruses. GVI-1 viruses exhibited variable antigenicity. GVI viruses showed an affinity for the respiratory tract of chickens.
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Abstract
Infectious bronchitis is a highly infectious disease of the domestic chicken of all ages and type, affecting the respiratory, renal and reproductive systems. Secondary bacterial infections are common and have a serious economic and welfare impact. Many genotypic and serotypic variants of infectious bronchitis virus (IBV) exist worldwide, making diagnosis difficult, and challenging control strategies. Vaccination, requiring the use of both live-attenuated and inactivated vaccines, is needed to control IBV infections; to date, attempts to develop vectored vaccines as effective as the traditional vaccines have been unsuccessful.
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Zhao Y, Xie D, Zhang K, Cheng J, Xu G, Zhang G. Pathogenicity of a GI-22 genotype infectious bronchitis virus isolated in China and protection against it afforded by GI-19 vaccine. Virus Res 2019; 267:59-66. [PMID: 31082454 PMCID: PMC7172295 DOI: 10.1016/j.virusres.2019.05.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/09/2019] [Accepted: 05/09/2019] [Indexed: 11/16/2022]
Abstract
A GI-22 genotype IBV strain LGD was isolated in northern China in 2018. We investigated the molecular characteristics and pathogenecity of LGD. The GI-19 type vaccine was efficacious against LGD challenge.
Avian infectious bronchitis (IB) is a globally circulating bird disease caused by infectious bronchitis virus (IBV). In China, the most prevalent IBV genotype is GI-19/QX-like because the protective efficiency of the classical IBV vaccine is low, and new GI-19 vaccines are under development. In 2018, a GI-22 genotype strain CK/CH/LGD/2018 (abbreviated ‘LGD’) was isolated in northern China, which caused 10%–30% morality in H120-vaccinated chickens. A phylogenetic analysis showed that this new isolate displays novel features compared with other earlier-isolated reference strains. To monitor the epidemic trend of IBV in China, the pathogenicity of LGD was first evaluated in 1-day-old specific-pathogen-free chickens. LGD induced classical IBV damage in the trachea and kidney, whereas it also infected and damaged the bursa of Fabricius, an important immune organ of chickens. The efficacy of our earlier-developed GI-19 vaccine, strain SZ200, against LGD was also evaluated in this study. The GI-19 genotype vaccine provided sufficient protection against the new GI-22 genotype strain, and may be a promising candidate vaccine with which to control both wild GI-19 and GI-22 strains in the future.
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Protection conferred by a vaccine derived from an inactivated Egyptian variant of infectious bronchitis virus: a challenge experiment. Trop Anim Health Prod 2019; 51:1997-2001. [PMID: 31020540 DOI: 10.1007/s11250-019-01898-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 04/11/2019] [Indexed: 12/14/2022]
Abstract
The current study investigated the protective efficacy of a formalin-inactivated infectious bronchitis virus (IBV) vaccine derived from the field strain KP729422, which exhibits low S1 spike protein sequence homology (77.1-79.8%) with the currently used vaccine strains in Egypt. Two-week-old, specific-pathogen-free chickens were subcutaneously inoculated with a single dose of the vaccine containing 106.7 50% embryo infective dose (EID50) of the inactivated virus. At 6 weeks of age, the chickens were challenged with 104 EID50 of the same virus strain via the oculonasal route. In comparison with the unvaccinated challenged group, the vaccinated chickens had significantly higher IBV-neutralizing antibody titers and exhibited efficient protection against challenge on the basis of tracheal ciliary activity. However, the challenge virus was recovered from the kidneys and tracheas of these chickens at rates of 40% and 60%, respectively. These findings suggest that a single application of the vaccine may provide sufficient clinical and respiratory protection, but may not ensure complete protection against infection by the challenge virus.
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Marandino A, Vagnozzi A, Craig MI, Tomás G, Techera C, Panzera Y, Vera F, Pérez R. Genetic and antigenic heterogeneity of infectious bronchitis virus in South America: implications for control programmes. Avian Pathol 2019; 48:270-277. [PMID: 30761909 DOI: 10.1080/03079457.2019.1583315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Infectious bronchitis virus (IBV) is a persistent sanitary problem for the South American poultry industry despite extensive vaccination. The IBV single-stranded RNA genome has high rates of mutation and recombination that generate a notorious virus variability. Since most IBV vaccines are type-specific, there is a need for constant surveillance of the circulating lineages and knowledge about their genetic and antigenic properties. Here we present an integrative analysis that provides the pattern of genetic variation of the South American IBV strains and information about their antigenic characteristics. The genetic analysis was performed using the S1 complete coding sequences of all available South American strains, including newly obtained Argentine and Uruguayan field samples. Our phylogenetic and phylodynamic analyses evidence that three main lineages (GI-1, GI-11 and GI-16) are extensively circulating in South American flocks. Strains of the GI-1 lineage (Massachusetts-type) were detected in Argentina, Brazil, Chile and Colombia. The GI-11 lineage is an exclusively South American lineage that emerged in the 1950s, and is the predominant lineage in Brazil and Uruguay at present. The GI-16 lineage emerged around 1979, and is currently circulating in most South American territories (Argentina, Chile, Uruguay, Colombia and Peru). The virus cross-neutralization test performed here reveals very low antigenic relatedness between GI-11 and GI-16 lineages (i.e. they are different serotypes). The results of this study extend our knowledge about the present and past IBV variability in South America and provide relevant elements to improve the control programmes by considering the genetic and antigenic attributes of IBV.
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Construction and Immunogenicity of Novel Chimeric Virus-Like Particles Bearing Antigens of Infectious Bronchitis Virus and Newcastle Disease Virus. Viruses 2019; 11:v11030254. [PMID: 30871190 PMCID: PMC6465995 DOI: 10.3390/v11030254] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/22/2022] Open
Abstract
Infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) are two poultry pathogens seriously affecting the poultry industry. Here, IBV S1 and the ectodomain of NDV F proteins were separately linked with the trans-membrane and carboxy-terminal domain of IBV S protein (STMCT), composing rS and rF; thus, a novel chimeric infectious bronchitis-Newcastle disease (IB-ND) virus-like particles (VLPs) vaccine containing the rS, rF, and IBV M protein was constructed. Under the transmission electron microscope (TEM), VLPs possessing similar morphology to natural IBV were observed. To evaluate the immunogenicity of chimeric IB-ND VLPs, specific pathogen-free (SPF) chickens were immunized with three increasing doses (50, 75, and 100 μg protein of VLPs). Results of ELISAs detecting IBV and NDV specific antibodies and IL-4 and IFN-γ T cell cytokines indicated that vaccination with chimeric IB-ND VLPs could efficiently induce humoral and cellular immune responses. In the challenge study, chimeric IB-ND VLPs (100 μg protein) provided 100% protection against IBV or NDV virulent challenge from death, and viral RNA levels in tissues and swabs were greatly reduced. Collectively, chimeric IB-ND VLPs are highly immunogenic and could provide complete protection from an IBV or NDV virulent challenge. Chimeric IB-ND VLPs are an appealing vaccine candidate and a promising vaccine platform bearing multivalent antigens.
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Toroghi R, Salarpour A, Momayez R. Nucleotide Sequence Analysis of S1 Gene among Iranian Avian Infectious Bronchitis Viruses Isolated during 2001-2002. ARCHIVES OF RAZI INSTITUTE 2019; 74:21-31. [PMID: 31013004 DOI: 10.22092/ari.2019.123468.1254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 01/01/2019] [Indexed: 09/30/2022]
Abstract
Infectious bronchitis (IB) virus genome codes for four structural proteins, among which the S1 subunit of spike glycoprotein comprises the major epitopes to induce neutralizing antibodies. This study involved the comparison of the full S1 sequences of five IB viruses, namely two Massachusetts and three 793/B serotypes, isolated from IB outbreaks during 2001-2002, with all other Iranian and foreign 793/B isolates and 10 known serotypes. Analysis of S1 subunit showed three unique amino acid changes at positions 349 (V to L), 392 (T to N), and 393 (Q or R to T or K or S) for the Iranian 793/B isolates, compared to those of the foreign 793/B isolates reported before 2006 (onset of vaccination with 793/B vaccine in Iran). They were used as amino acid markers for the differentiation of Iranian 793/B isolates for years. Sequence alignment of the Iranian isolates with those of the foreign ones reported after 2006 demonstrated that amino acids 392 and 393 were no longer considered as amino acid markers, and only the change in amino acid 349 still remained specific to the Iranian 793/B isolates. Phylogenetic tree sequence analysis revealed that the Iranian 793/B isolates were closely related indicating that they came from a single source, more probably from France. There was a very close correlation between the first detection of 793/B serotype and the time of French chicken meat importation. Moreover, it was shown that one of the Massachusetts isolates was completely identical with the H120 vaccine strain. Furthermore, the other Massachusetts isolate with two amino acid changes at positions 64 (G to E) and 95 (S to R) was very similar to this vaccine strain. It seems that the latter isolate is a passaged chicken H120 vaccine strain.
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Aston EJ, Jordan BJ, Williams SM, García M, Jackwood MW. Effect of Pullet Vaccination on Development and Longevity of Immunity. Viruses 2019; 11:E135. [PMID: 30717342 PMCID: PMC6409539 DOI: 10.3390/v11020135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 12/16/2022] Open
Abstract
Avian respiratory disease causes significant economic losses in commercial poultry. Because of the need to protect long-lived poultry against respiratory tract pathogens from an early age, vaccination programs for pullets typically involve serial administration of a variety of vaccines, including infectious bronchitis virus (IBV), Newcastle disease virus (NDV), and infectious laryngotracheitis virus (ILTV). Often the interval between vaccinations is only a matter of weeks, yet it is unknown whether the development of immunity and protection against challenge when vaccines are given in short succession occurs in these birds, something known as viral interference. Our objective was to determine whether serially administered, live attenuated vaccines against IBV, NDV, and ILTV influence the development and longevity of immunity and protection against challenge in long-lived birds. Based on a typical pullet vaccination program, specific-pathogen-free white leghorns were administered multiple live attenuated vaccines against IBV, NDV, and ILTV until 16 weeks of age (WOA), after which certain groups were challenged with IBV, NDV, or ILTV at 20, 24, 28, 32, and 36 WOA. Five days post-challenge, viral load, clinical signs, ciliostasis, tracheal histopathology, and antibody titers in serum and tears were evaluated. We demonstrate that pullets serially administered live attenuated vaccines against IBV, NDV, and ILTV were protected against homologous challenge with IBV, NDV, or ILTV for at least 36 weeks, and conclude that the interval between vaccinations used in this study (at least 2 weeks) did not interfere with protection. This information is important because it shows that a typical pullet vaccination program consisting of serially administered live attenuated vaccines against multiple respiratory pathogens can result in the development of protective immunity against each disease agent.
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Chicken anaemia virus enhances and prolongs subsequent avian influenza (H9N2) and infectious bronchitis viral infections. Vet Microbiol 2019; 230:123-129. [PMID: 30827377 DOI: 10.1016/j.vetmic.2019.01.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/15/2019] [Accepted: 01/27/2019] [Indexed: 01/01/2023]
Abstract
Immunosuppressive viral diseases have a great economic importance in the poultry industry due to the increased susceptibility to secondary infections. Chicken anaemia virus (CAV) is one of the major immunosuppressive diseases in chickens. In addition, low pathogenic avian influenza (LPAI) of subtype H9N2 and infectious bronchitis (IB) viruses are among the most frequently reported respiratory viral diseases in poultry worldwide. In the present study, specific pathogen free chickens were used to understand the impact of CAV on secondary infection with LPAI-H9N2 or IB viruses. Clinical outcomes, viral shedding dynamics, and cytokine levels wereassessed. The results exhibit that chickens previously infected with CAV produceconsiderablyhigher titresof LPAI-H9N2 or IB viruses in the oropharyngeal swabs (P < 0.05), tracheas and kidneys. In addition, the immunologic effect of CAV provokedthe development of clinical signs of LPAI-H9N2 and IB virus infections. Moreover, results suggested that pre-infection with CAV directly correlated with elevated levels of IL-6 and IFNγ. These findings underline the importance of CAV pre-infection on LPAI-H9N2 or IB infection in chickens, and indicate that co-circulation of CAV can contribute to the spread and evolution of LPAI H9N2 and IB viruses.
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Yilmaz H, Faburay B, Turan N, Cotton-Caballero M, Cetinkaya B, Gurel A, Yilmaz A, Cizmecigil UY, Aydin O, Tarakci EA, Bayraktar E, Richt JA. Production of Recombinant N Protein of Infectious Bronchitis Virus Using the Baculovirus Expression System and Its Assessment as a Diagnostic Antigen. Appl Biochem Biotechnol 2019; 187:506-517. [PMID: 29987628 PMCID: PMC7090399 DOI: 10.1007/s12010-018-2815-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 06/05/2018] [Indexed: 11/26/2022]
Abstract
The avian coronavirus-infectious bronchitis virus (AvCoV-IBV) is recognized as an important avian pathogen, and new viral variants are a continuous threat to the poultry industry worldwide. Sensitive diagnostics and efficacious vaccines are necessary to combat IBV infections in chickens. The aim of this study was to produce recombinant N protein of IBV in the baculovirus system to use in ELISA diagnostic tests in order to enable the assessment of the sero-prevalence and risk of IBV infections in chickens in Turkey. For this, the gene encoding the N protein of the Beaudette strain of IBV was expressed using a recombinant baculovirus expression system. The recombinant N protein was purified using Ni-NTA affinity chromatography. An estimated 50-kDa recombinant protein corresponding to the expected molecular weight of IBV N including the 6xHis tag was detected using an anti-His monoclonal antibody. Specific immunoreactivity of the recombinant protein was confirmed by Western blot using antiserum obtained from vaccinated and naturally infected chicken from Turkey as well as using a monoclonal antibody raised against the N protein of the IBV Massachusetts strain. The results obtained with the in-house ELISA had high agreement with a commercial ELISA. Immunoreactivity analysis using antisera in Western blotting and the in-house ELISA suggests that the recombinant IBV N protein could be broadly cross-reactive with antisera produced against different IBV strains. We conclude that the recombinant baculovirus expressed IBV N protein could serve as a useful diagnostic antigen for detection of IBV infections in chickens by ELISA.
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93
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Ma T, Xu L, Ren M, Shen J, Han Z, Sun J, Zhao Y, Liu S. Novel genotype of infectious bronchitis virus isolated in China. Vet Microbiol 2019; 230:178-186. [PMID: 30827386 PMCID: PMC7117389 DOI: 10.1016/j.vetmic.2019.01.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Revised: 01/09/2019] [Accepted: 01/27/2019] [Indexed: 12/16/2022]
Abstract
Recombination events are known to contribute to the emergence of novel infectious bronchitis virus (IBV) genotypes. In this study, we carried out detailed phylogenetic analysis and sequence comparisons based on 74 complete nucleotide sequences of the IBV S1 gene, including strain I0636/16 and 73 representative sequences from each genotype and lineage. The results showed that strain I0636/16 represented a novel genotype, designated as lineage 1 within genotype VII (GVII-1). Further comparative genomic analysis revealed at least two recombination sites that replaced the spike gene in a lineage 18 within genotype I (GI-18)-like virus with an as-yet-unidentified sequence, likely derived from another IBV strain, resulting a novel serotype with a lower affinity to the respiratory tract in chickens. To the best of our knowledge, this provides the first evidence for recombination leading to replacement of the complete spike gene and the emergence of a novel genotype/serotype with a lower affinity to the respiratory tract in chickens comparing to one of its parental virus ck/CH/LGX/111119. These results emphasize the importance of limiting exposure to novel IBVs that may serve as a source of genetic material for emerging viruses, as well as the importance of IBV surveillance in chicken flocks.
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94
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Lee G, Choi H, Sureshkumar S, Jung SK, Kim JS, Oh KB, Kim KW, Yang H, Kim DH, Byun SJ. The 3D8 single chain variable fragment protein suppress infectious bronchitis virus transmission in the transgenic chickens. Res Vet Sci 2019; 123:293-297. [PMID: 30738233 PMCID: PMC7111750 DOI: 10.1016/j.rvsc.2019.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/28/2018] [Accepted: 01/22/2019] [Indexed: 11/29/2022]
Abstract
Infectious bronchitis (IB) generated by the infectious bronchitis virus (IBV) causes economic difficulties for livestock farmers. The 3D8 single chain variable fragment (scFv) protein is a recombinant antibody with nuclease activity that shows antiviral effects against various DNA and RNA viruses in mice and chickens. In this experiment, 3D8 scFv G2 transgenic chickens produced by crossing 3D8 scFv G1 transgenic rooster and wild type hens were screened by genomic PCR and immunohistochemistry analysis. 3D8 scFv transgenic chickens, wild type sibling chickens, and SPF chickens were directly infected with IBV (5 chickens per group) and indirectly infected by airborne propagation (15 chickens per group). The relative IBV shedding titers were measured by quantitative real-time PCR using oropharyngeal and cloacal swabs on days 3 and 5 after intraocular infection. The viral load was significantly decreased in the 3D8 scFv transgenic chickens from the contact transmission group. Additionally, blood was collected from each group on day 17 post-infection. The ELISA results showed a marked reduction of the antibody titer against IBV in the 3D8 scFv transgenic chickens from the contact transmission group. These results suggest that the 3D8 scFv protein potentially inhibits infectious bronchitis virus transmission in chickens. Produced G2 3D8 single chain variable fragment (scFv) transgenic chickens. 3D8 scFv transgenic chickens showed reduced infectious bronchitis viral shedding level in the contact transmission group. 3D8 scFv transgenic chickens were 40% lower than the response in the control groups in IBV serum antibody titer.
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95
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Xu L, Ren M, Sheng J, Ma T, Han Z, Zhao Y, Sun J, Liu S. Genetic and biological characteristics of four novel recombinant avian infectious bronchitis viruses isolated in China. Virus Res 2019; 263:87-97. [PMID: 30641197 PMCID: PMC7185608 DOI: 10.1016/j.virusres.2019.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/29/2018] [Accepted: 01/10/2019] [Indexed: 01/22/2023]
Abstract
Two IBV strains were proved to be originated from multiple recombination events. Viruses with very similar S1 gene sequences showed varying biological features. Point mutations were observed in the RBD and HVRs of the recombinant viruses. Point mutations likely have an effect on these differences in biological characteristics.
Infectious bronchitis viruses (IBVs) of GI-13 (793/B) and GI-19 (QX/LX4) lineages have been frequently detected in China in recent years. Naturally recombinant IBVs originating from the GI-13 and GI-19 lineages have also been isolated from chicken flocks with respiratory and renal problems in China. Thorough genetic and biological investigations of these recombinant viruses have led to speculation regarding their origin, evolution, and control. In order to confirm the previous results and further extend our understanding about the characteristics of the four recombinant IBV strains we had previously identified (I0718/17, I0722/17, I0724/17, and I0737/17), we conducted phylogenetic analysis by comparing their complete S1 gene sequences with those of 71 reference strains of different genotypes and lineages. We identified a close relationship between the S1 sequences of the four strains and those of GI-13 strains. The results of complete genome sequence analysis confirmed the previously identified recombination events in the four IBV strains and revealed additional recombination events in different genomic regions of strains I0718/17 and I0724/17, suggesting that the two strains originated from multiple recombination events between 4/91-like and YX10-like viruses. We comparatively evaluated the antigenicity, pathogenicity, and affinity of the four recombinant viruses and their deduced parental strains in the trachea and kidneys. Some of the strains showed comparable antigenic relatedness, pathogenicity, and affinity for the trachea and kidneys among each other and with their parental viruses; however, some of them showed varying biological characteristics. Point mutations observed in the receptor-binding domain and hypervariable region of the S1 subunit of the spike protein likely have an effect on these differences in biological characteristics, although the influence of other factors—such as host innate-immune responses and changes in genomic regions beyond the S1 protein—might also be responsible for such changes.
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Gonadal pathogenicity of an infectious bronchitis virus strain from the Massachusetts genotype. Braz J Microbiol 2018; 50:313-320. [PMID: 30637657 PMCID: PMC6863202 DOI: 10.1007/s42770-018-0007-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 06/20/2018] [Indexed: 12/11/2022] Open
Abstract
An outbreak of infectious bronchitis caused by the IBVPR03 strain of the Massachusetts genotype affected H-120 vaccinated laying hens in South Brazil. We investigated the cross protection of the vaccine by assessing the traqueal ciliostasis, virus recovery, and histopathological changes typically observed in the respiratory tract. Although the IBVPR03 strain is S1-genotyped as Massachusetts with a high genomic similarity to the H-120 vaccine strains, surprisingly, we found no tropism or pathogenicity to the trachea in birds infected with this strain. On the other hand, we observed ovarian and testicle lesions. Here, we show that, despite belonging in the Massachusetts genotype, the IBVPR03 pathotype differs from the expected respiratory pattern, causing instead marked histopathological changes in the gonads, so far not associated with this group.
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Amarasinghe A, De Silva Senapathi U, Abdul-Cader MS, Popowich S, Marshall F, Cork SC, van der Meer F, Gomis S, Abdul-Careem MF. Comparative features of infections of two Massachusetts (Mass) infectious bronchitis virus (IBV) variants isolated from Western Canadian layer flocks. BMC Vet Res 2018; 14:391. [PMID: 30526618 PMCID: PMC6288874 DOI: 10.1186/s12917-018-1720-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Infectious bronchitis virus (IBV) is one of the leading causes of mortality and morbidity in chickens. There are numerous serotypes and variants, which do not confer cross protection resulting in failure of currently used IBV vaccines. Although variant IBV isolates with major genetic differences have been subjected to comparative studies, it is unknown whether minor genetic differences in IBV variants within a serotype are different in terms of pathogenesis and eliciting host responses. Two Massachusetts (Mass) variant IBV isolates recovered from commercial layer flocks in the Western Canadian provinces of Alberta (AB) and Saskatchewan (SK) were compared genetically and evaluated for their pathogenicity, tissue distribution and ability to recruit and replicate in macrophages. RESULTS Although whole genome sequencing of these two Mass IBV isolates showed low similarity with the M41 vaccinal strain, they had an identical nucleotide sequence at open reading frames (ORFs) 3a, 3b, envelop (E), matrix (M), 5a and 5b. The rest of the ORFs of these 2 IBV isolates showed 99.9% nucleotide similarity. However, upon experimental infection, we found that the IBV isolate originating from AB was different to the one that originated in SK due to higher tracheal lesion scores and lower lung viral replication and lower genome loads in cecal tonsils. Nevertheless, both IBV isolates elicited host responses characterized by significant macrophage recruitment to the respiratory tract and there was evidence that both IBV isolates replicated within tracheal and lung macrophages. CONCLUSIONS Overall, this study shows that Mass variant IBV isolates, although possessing minor genetic variations, can lead to significant differences in pathogenicity in young chickens. Further studies are required to investigate the pathogenicity of these two Mass variant IBV isolates in laying hens.
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Pathogenicity differences between a newly emerged TW-like strain and a prevalent QX-like strain of infectious bronchitis virus. Vet Microbiol 2018; 227:20-28. [PMID: 30473347 DOI: 10.1016/j.vetmic.2018.10.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/17/2018] [Accepted: 10/23/2018] [Indexed: 12/16/2022]
Abstract
TW-like IBV isolates have appeared frequently in recent years in mainland China. In this study, we compared the TW-like IBV GD strain and the predominant QX-like SD strain in terms of serology and pathogenicity to 3-week-old specific-pathogen-free chickens. Both strains could cause severe respiratory distress and renal lesions, with a mortality rate were approximately 20%. Virus were continuously shed via the respiratory tract and cloaca. However, the infection pattern of the two isolates were different. The GD strain persisted for a longer duration and caused extensive damages to the tracheas and lungs. Moreover, chickens infected with the GD strain showed inefficient recovery of damaged cilia after infection. Our findings suggested that the newly emerged TW-like IBV GD strain showed obvious differences in pathogenicity, tissue tropism and replication efficiency compared with the QX-like IBV SD strain, with the TW-like GD strain showing stronger tropism to the respiratory tract and a longer duration of clinical signs.
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Chhabra R, Ball C, Chantrey J, Ganapathy K. Differential innate immune responses induced by classical and variant infectious bronchitis viruses in specific pathogen free chicks. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 87:16-23. [PMID: 29751011 PMCID: PMC7173069 DOI: 10.1016/j.dci.2018.04.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/30/2018] [Accepted: 04/30/2018] [Indexed: 06/08/2023]
Abstract
Avian infectious bronchitis virus (IBV) continues to cause serious economic losses in global chicken production. Concurrent circulation of both classic and variant IBVs have been identified in most parts of the world, raising major challenges to global prevention and control efforts. Therefore, immunopathogenesis, particularly early host responses, needs to be better understood for effective control of diseases caused by different strains of IBVs. We investigated differing immunopathogenesis in chickens following infection with IS/885/00-like (885), QX-like (QX) and M41 IBV strains. We confirmed that the histopathological changes, proinflammatory and innate immune gene responses were induced to different magnitudes, depending on the IBV strain. Results indicated that upregulation of proinflammatory cytokines (such as IL-6 and IL-1β) and lipopolysaccharide-induced tumor necrosis factor-alpha factor (LITAF) expression is induced by IBV M41 in the trachea and by IBV 885 and QX in the kidney, which mainly coincides with tracheal and renal histopathological lesions respectively caused by these strains. In addition, elevated levels of TLR3, MDA5 and IFN-β expression occurred concurrently with greater lesion severity in IBV infected trachea and kidney tissues. Overall, this study reports marked differences in the activation of early host responses by pathogenic IBV strains.
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Ball C, Forrester A, Ganapathy K. Co-circulation of genetically diverse population of vaccine related and unrelated respiratory mycoplasmas and viruses in UK poultry flocks with health or production problems. Vet Microbiol 2018; 225:132-138. [PMID: 30322525 DOI: 10.1016/j.vetmic.2018.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/06/2018] [Accepted: 09/16/2018] [Indexed: 11/26/2022]
Abstract
Respiratory diseases continue to have a major impact on poultry health, welfare and productivity. However, little information is available on their current status in UK poultry flocks. We investigated the presence of four economically important respiratory pathogens in healthy or problematic flocks; infectious bronchitis virus (IBV), avian metapneumovirus (aMPV), Mycoplasma gallisepticum (Mg) and Mycoplasma synoviae (Ms). Samples from 131 UK poultry flocks were received during the 12 month study period. Oropharyngeal (OP) swabs were taken from eight birds per flock and accompanied with flock health information. The study included 118 chicken, 6 pheasant and 5 turkey flocks, and 1 quail and 1 partridge flock. Chicken flocks were of layers (n = 98), broilers (n = 15), breeders (n = 3) and undisclosed (n = 2). Flock ages ranged from 3 to 72 weeks old, and the average flock size was 17,633 birds. PCR detected 65 (49.6%), 59 (45%) and 8 (6.1%) flocks as positive for IBV, Mg/Ms and aMPV respectively. Analysis of the mgc2 gene of the Mg isolates revealed high similarities to Mg TS-11 and Mg 6/85. Further gene analysis found that the TS-11-like isolates were unrelated to the TS-11 vaccine. Multi-locus sequence typing (MLST) analysis identified the majority of positive Ms as ST21, along with ST2 (MS-H-like), ST6 and ST43. IBV S1 gene sequencing identified strains as 793B (66.7%), Arkansas (23.8%) and Massachusetts (9.5%). All aMPV positive samples belonged to subtype B. Findings indicate that over half of the flocks sampled were positive for at least one of the four vaccine or field strains of mycoplasmas or viruses.
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