Infectious Bronchitis Virus Isolates Research Articles

Molecular Characterization of QX-Like and Variant Infectious Bronchitis Virus Strains in Malaysia Based on Partial Genomic Sequences Comprising the S-3a/3b-E-M-Intergenic Region-5a/5b-N Gene Order.

Infectious bronchitis virus (IBV) is one of the major poultry pathogens of global importance. However, the prevalence of IBV strains in Malaysia is poorly characterized. The partial genomic sequences (6.8 kb) comprising the S-3a/3b-E-M-intergenic region-5a/5b-N gene order of 11 Malaysian IBVs isolated in 2014 and 2015 were sequenced using next-generation sequencing technology. Phylogenetic and pairwise sequence comparison analysis showed that the isolated IBVs are divided into two groups. Group 1 (IBS124/2015, IBS125/2015, IBS126/2015, IBS130/2015, IBS131/2015, IBS138/2015, and IBS142/2015) shared 90%-95% nucleotide and deduced amino acid similarities to the QX-like strain. Among these isolates, IBS142/2015 is the first IBV detected in Sarawak state located in East Malaysia (Borneo Island). Meanwhile, IBV isolates in Group 2 (IBS037A/2015, IBS037B/2015, IBS051/2015, and IBS180/2015) were 91.62% and 89.09% identical to Malaysian variant strain MH5365/95 (EU086600) at nucleotide and amino acid levels, respectively. In addition, all studied IBVs were distinctly separate from Massachusetts (70%-72% amino acid similarity) and European strains including 793/B, Italy-02, and D274 (68%-73% amino acid similarity). Viruses in Group 1 have the insertion of three amino acids at positions 23, 121, and 122 of the S1 protein and recombinant events detected at nucleotide position 4354-5864, with major parental sequence derived from QX-like (CK-CH-IBYZ-2011) and a minor parental sequence derived from Massachusetts vaccine strain (H120). This study demonstrated coexistence of the IBV Malaysian variant strain along with the QX-like strain in Malaysia.

Isolation and Characteristics of the Arkansas-Type Infectious Bronchitis Virus in China.

Two infectious bronchitis virus (IBV) strains, designated as γCoV/ck/China/I0712/11 (I0712/11) and γCoV/ck/China/I0108/17 (I0108/17), were isolated from diseased chicken flocks in different provinces in China and genotyped as Arkansas (Ark)-type viruses with three other Chinese Ark field strains, the Jilin vaccine strain, and the American Ark- and Ark DPI-like viruses. Complete genomic sequence analysis and pairwise comparison of nucleotide sequences encoding the S1 subunit of the spike protein and other structural and accessory proteins revealed that Chinese Ark field isolates were genetically closely related to the Jilin vaccine and American ArkDPI11 strains, although extensive nucleotide changes were found across the genomes of Chinese Ark field isolates. This suggests that Chinese Ark-type isolates are derived from the Jilin vaccine, and have diverged and evolved independently by point mutations since introduction into China. It is also possible that the Chinese Ark viruses have arisen as a result of different introductions of American ArkDPI11-like strains from the United States; this hypothesis requires further investigation. Pathogenicity testing showed that Chinese Ark viruses had comparable virulence to that of the Massachusetts-type M41 strain, although they had lower affinity for the kidneys of chickens than the M41 strain had. Although Ark-type viruses are not widespread in China, surveillance and updating the currently applied vaccination strategy for sound protection against IBV disease are important because this type of virus has caused heavy economic losses in the United States.

Assessment of molecular and genetic evolution, antigenicity and virulence properties during the persistence of the infectious bronchitis virus in broiler breeders.

The infectious bronchitis virus (IBV) causes a highly contagious disease [infectious bronchitis (IB)] that results in substantial economic losses to the poultry industry worldwide. We conducted a molecular and phylogenetic analysis of the S1 gene of Brazilian (BR) IBV isolates from a routinely vaccinated commercial flock of broiler breeders, obtained from clinical IB episodes that occurred in 24-, 46- and 62-week-old chickens. We also characterized the antigenicity, pathogenesis, tissue tropism and spreading of three IBV isolates by experimental infection of specific pathogen-free (SPF) chickens and contact sentinel birds. The results reveal that the three IBV isolates mainly exhibited mutations in the hypervariable regions (HVRs) of the S1 gene and protein, but were phylogenetically and serologically closely related, belonging to lineage 11 of the GI genotype, the former BR genotype I. All three isolates caused persistent infection in broiler breeders reared in the field, despite high systemic anti-IBV antibody titres, and exhibited tropism and pathogenicity for the trachea and kidney after experimental infection in SPF chickens and contact birds. In conclusion, BR genotype I isolates of IBV evolve continuously during the productive cycle of persistently infected broiler breeders, causing outbreaks that are not impaired by the current vaccination programme with Massachusetts vaccine strains. In addition, the genetic alterations in the S1 gene of these isolates were not able to change their tissue tropism and pathogenicity, but did seem to negatively influence the effectiveness of the host immune responses against these viruses, and favour viral persistence.

Variability in biological behaviour, pathogenicity, protectotype and induction of virus neutralizing antibodies by different vaccination programmes to infectious bronchitis virus genotype Q1 strains from Chile

ABSTRACTIn the period from July 2008 to 2010, a disease episode resulting in serious economic losses in the major production area of the Chilean poultry industry was reported. These losses were associated with respiratory problems, increase of condemnations, drops in egg production and nephritis in breeders, laying hens and broilers due to infections with infectious bronchitis virus (IBV). Twenty-five IBV isolates were genotyped and four strains were selected for further testing by pathotyping and protectotyping. Twenty-four IBV isolates were of the Q1 genotype. The experiments also included comparing the ability of six vaccination programmes to induce virus neutralizing antibodies (VNA) in layers against four selected Chilean strains. Despite the high genetic homology in the S1 gene between the four strains, the heterogeneity in biological behaviour of these different Q1 strains was substantial. These differences were seen in embryonated eggs, in cell culture, in pathogenicity and in level of cross-protection by IBV Massachusetts (Mass) vaccination. This variability underlines the importance of testing more than one strain per serotype or genotype to determine the characteristics of a certain serotype of genotype. The combination of Mass and 793B vaccine provided a high level of protection to the respiratory tract and the kidney for each strain tested in the young birds. The combination of broad live priming using Mass and 793B vaccines and boosting with multiple inactivated IBV antigens induced the highest level of VNA against Q1 strains, which might be indicative for higher levels of protection against Q1 challenge in laying birds.

Genome characterization, antigenicity and pathogenicity of a novel infectious bronchitis virus type isolated from south China

In 2014, three infectious bronchitis virus (IBV) strains, designated as γCoV/ck/China/I0111/14, γCoV/ck/China/I0114/14 and γCoV/ck/China/I0118/14, were isolated and identified from chickens suspected to be infected with IBV in Guangxi province, China. Based upon data arising from S1 sequence and phylogenetic analyses, the three IBV isolates were genetically different from other known IBV types, which represented a novel genotype (GI-29). Virus cross-neutralization tests, using γCoV/ck/China/I0111/14 as a representative, showed that genotype GI-29 was antigenically different from all other known IBV types, thus representing a novel serotype. Complete genomic analysis showed that GI-29 type viruses were closely related to and might originate from a GX-YL5-like virus by accumulation of substitutions in multiple genes. These GI-29 viral genomes are still evolving and diverging, particularly in the 3′ region, although we cannot rule out the possibility of recombination events occurring. For isolate γCoV/ck/China/I0114/14, we found that recombination events had occurred between nsps 2 and 3 in gene 1 which led to the introduction of a 4/91 gene fragment into the γCoV/ck/China/I0114/14 viral genome. In addition, we found that the GI-29 type γCoV/ck/China/I0111/14 isolate was a nephropathogenic strain and high pathogenic to 1-day-old specific pathogen-free (SPF) chickens although cystic oviducts were not observed in the surviving layer chickens challenged with γCoV/ck/China/I0111/14 isolate.

Genotyping of Avian infectious bronchitis viruses in Iran (2015–2017) reveals domination of IS-1494 like virus

Avian infectious bronchitis virus (IBV) is causing major economic losses to the poultry industry. The analysis of the S1 gene has been used to determine IBV genotype. The aim of this study was genotyping of IBVs circulating among the Iranian broiler flocks in the period between 2015 to 2017. Trachea samples from 278 broiler flocks were collected from broiler farms in eight provinces of Iran. After Real-time RT-PCR, IBV-positive samples were further characterized based on S1 gene. The results of the Real-time RT-PCR showed that 52.16% of flocks were IBV positive. Four genotypes were detected and the frequency of occurrence rates of IS-1494-like, 793/B, QX and Massachusetts IBV genotypes were 70.34%, 19.31%, 7.58% and 2.75%, respectively. Sequence analysis revealed that nucleotide identities within IS-1494-like group ranged between 98.86–100%, while each of the QX, Massachusetts and 793/B groups were 98.05–100%, 98.20–100% and 93.29–100% respectively. These results show that the IS-1494-like IBV is the dominant IBV genotype in Iran. Proper control strategies are essential to overcoming the high frequency of occurrence of IS-1494-like IBV. The phylogenetic relationship of the strains with respect to different sequences and geographical regions displayed complexity and diversity. Further studies are needed and should include the isolation and full-length molecular characterization of IBV in Iran.

Epidemiology and characterization of avian infectious bronchitis virus strains circulating in southern China during the period from 2013\u20132015

Two hundred and six strains of avian infectious bronchitis virus (IBV) were isolated from chickens showing signs of disease in southern China during the period from 2013–2015. The nucleotide and amino acid sequences from the isolated field strains were compared to 42 published references. Nucleotide homologies ranged from 63.1–99.9% and amino acid homologies ranging from 60.2–100%. At least seven IBV genotypes were co-circulating in commercial chicken farms in southern China. The IBV isolates were genetically diverse and underwent continuing evolution. The QX-type, TW I-type, and 4/91-type were the most common genotypes during the three-year observation period and accounted for 88.8% of the isolated strains. Notably, the prevalence of the TW I-type strains has been increasing in recent years and has become the most common genotype in China. The emergence of variant IBV strains can be attributed to recombination. Serologic analysis and antigenic 3D cartography of 4 reference and 14 field isolated strains indicated the surveyed IBVs had diverse serology types and that the serotype of the isolated QX-type and TW I-type strains was distinct from the vaccines strains. Therefore, long-term continuing surveillance is necessary for IBV prevention and control.

Different evolutionary trajectories of vaccine-controlled and non-controlled avian infectious bronchitis viruses in commercial poultry.

To determine the genetic and epidemiological relationship of infectious bronchitis virus (IBV) isolates from commercial poultry to attenuated live IBV vaccines we conducted a phylogenetic network analysis on the full-length S1 sequence for Arkansas (Ark), Massachusetts (Mass) and Delmarva/1639 (DMV/1639) type viruses isolated in 2015 from clinical cases by 3 different diagnostic laboratories. Phylogenetic network analysis of Ark isolates showed two predominant groups linked by 2 mutations, consistent with subpopulations found in commercial vaccines for this IBV type. In addition, a number of satellite groups surrounding the two predominant populations were observed for the Ark type virus, which is likely due to mutations associated with the nature of this vaccine to persist in flocks. The phylogenetic network analysis of Mass-type viruses shows two groupings corresponding to different manufacturers vaccine sequences. No satellite groups were observed for Mass-type viruses, which is consistent with no persistence of this vaccine type in the field. At the time of collection, no vaccine was being used for the DMV/1639 type viruses and phylogenetic network analysis showed a dispersed network suggesting no clear change in genetic distribution. Selection pressure analysis showed that the DMV/1639 and Mass-type strains were evolving under negative selection, whereas the Ark type viruses had evolved under positive selection. This data supports the hypothesis that live attenuated vaccine usage does play a role in the genetic profile of similar IB viruses in the field and phylogenetic network analysis can be used to identify vaccine and vaccine origin isolates, which is important for our understanding of the role live vaccines play in the evolutionary trajectory of those viruses.

Isolation and Molecular Characterization of Infectious Bronchitis Virus from Broiler Chickens, Egypt during 2014 -2016

Isolation and Molecular Characterization of Infectious Bronchitis Virus from Broiler Chickens, Egypt during 2014 -2016

Isolation and Molecular Characterization of Infectious Bronchitis Virus from Broiler Chickens, Egypt during 2014 -2016

In this study,surveillance on infectious bronchitis virus strains in 75 Egyptian broiler chicken flocks was performed using real-time RT-PCR at eight Governorates during 2014-2016. The birds in the selected flocks were suffering from respiratory and renal manifestations. The results of the present study showed that 31 (41%) samples were positive for IBV. All isolates were classified as variants using sequencing analysis of the obtained data and can be divided into 2 groups. Group I (variant) Egyptian IBV included isolates, EG-F728-1-2015-SP1, EG-F728-7-2015-SP1, EG-F862-3-2015-SP1, EG-F862-4-2015-SP1, EG-F888-2015-SP1, EG-F777-2015-SP1 and EG-F183-1-2016-SP1 which were very close to IBV-IS-1494-06 and had amino acid sequence identities between 87.5% to 96.2%. Group II (variant) Egyptian IBV included isolates, EG-F183-2-2016-SP1 and EG-F183-3-2016-SP1. These two IBV isolates were very close to IBV-IS/885 (variant 2) and they shared amino acid sequence identities from 92.3% to 97.1% with each other. In conclusion, different variants of IBV are present in broiler farms in high prevalence rate even in vaccinated flocks.

Early immune responses and development of pathogenesis of avian infectious bronchitis viruses with different virulence profiles

Avian infectious bronchitis virus (IBV) primarily replicates in epithelial cells of the upper respiratory tract of chickens, inducing both morphological and immune modulatory changes. However, the association between the local immune responses induced by IBV and the mechanisms of pathogenesis has not yet been completely elucidated. This study compared the expression profile of genes related to immune responses in tracheal samples after challenge with two Brazilian field isolates (A and B) of IBV from the same genotype, associating these responses with viral replication and with pathological changes in trachea and kidney. We detected a suppressive effect on the early activation of TLR7 pathway, followed by lower expression levels of inflammatory related genes induced by challenge with the IBV B isolate when compared to the challenge with to the IBV A isolate. Cell-mediated immune (CMI) related genes presented also lower levels of expression in tracheal samples from birds challenged with B isolate at 1dpi. Increased viral load and a higher percentage of birds with relevant lesions were observed in both tracheal and renal samples from chickens exposed to challenge with IBV B isolate. This differential pattern of early immune responses developed after challenge with IBV B isolate, related to the downregulation of TLR7, leading to insufficient pro-inflammatory response and lower CMI responses, seem to have an association with a most severe renal lesion and an enhanced capability of replication of this isolate in chicken.

Genetic, antigenic, and pathogenic characteristics of avian infectious bronchitis viruses genotypically related to 793/B in China

In this study, 20 infectious bronchitis virus (IBV) strains, which were genotypically related to 793/B, as assessed by an S1 gene comparison and a complete genomic sequence analysis, were isolated and identified from 2009 to 2014 in China. Phylogenetic analysis, network tree, similarity plot analysis, Recombination Detection Program 4(RDP4) and sequence comparison revealed that 12 of the 20 isolates were likely the reisolated vaccine virus. One isolate, ck/CH/LSD/110857, was shown to have originated from recombination events between H120- and 4/91-like vaccine strains that did not result in changes of antigenicity and pathogenicity. The remaining seven IBV isolates were shown to have originated from recombination events between a 4/91-like vaccine strain and a GX-LY9-like virus, which were responsible for the emergence of a novel serotype. A vaccination-challenge test found that vaccination with the 4/91 vaccine strain did not provide protection against challenge with the recombinant viruses. In addition, the results showed that the recombination events between the vaccine and field strains resulted in altered genetics, serotype, antigenicity, and pathogenicity compared with those of their deduced parental viruses. The results are important not only because this virus is of economic importance to poultry industry, but also because it is important for elucidating the origin and evolution of other coronaviruses.

Isolation and Molecular Characterization of a Variant Infectious Bronchitis Virus in Kafrelsheikh, Egypt During 2016

Isolation and Molecular Characterization of a Variant Infectious Bronchitis Virus in Kafrelsheikh, Egypt During 2016

Molecular characterization of infectious bronchitis virus (IBV) isolated from commercial chicken farms

Infectious bronchitis virus (IBV) primarily causes a highly infectious bronchitis (IB) in commercial chickens. Virus isolation and identification is necessary for diagnosis of the disease. In this study, a total of 5 IBV isolates that isolated from commercial poultry farms were isolated by inoculation in 9 day-old embryonated SPF eggs. After few passages, the embryos showed typical lesions of IB such as stunted and curled cross with feather dystrophy. Then, the 5 IBV isolates were characterized by RT-PCR followed by DNA sequencing of partial S1 gene. The phylogenetic analysis shows that the 5 IBV isolates distinctly clustered into 3 groups. Group 1 including IBV1/15, IBV2/15 and IBV3/15 shared more than 99% similarity with IBV genotype 793/B. Group 2 consisting of isolate IBV4/15 was closely related to genotype QX-like with the similarity of 98%.Interestingly, group 3consisting of IBV5/15 had genetic distance ranged from 8% to 10% with other reported IBV genotypes such as 793/B, Massachusetts-type, Taiwan-type and QX-like viruses whilstIBV5/15 shared about 99% similarities with a nephropathogenic Malaysian IBV isolate.

Full-length genome sequencing analysis of avian infectious bronchitis virus isolate associated with nephropathogenic infection

Infectious bronchitis virus (IBV) produces infectious bronchitis (IB) disease in poultry worldwide. In spite of proper vaccinations against the IBV, new IBV strains are continually emerging worldwide. In this study, a new highly virulent nephropathogenic IBV strain named CK/CH/XDC-2/2013 was identified from a vaccinated flock with clinical signs of IB in the Jiangsu province of China. The full-length genome sequence of the isolate was 27,714 nucleotides long, and the genome was organized similarly to classical IBV strains. Minimum divergence, phylogenetic analysis, and distance matrix of the genome showed that the CK/CH/XDC-2/2013 isolate had the highest similarity to the IBV BJ strain. The spike glycoprotein (S) gene had the greatest similarity to the nephropathogenic BJ strain and showed an 8 amino acid insertion (YSNGNSDV) at 73 to 80 sites and 3 amino acid deletion at sites 126 to 128 compared to the IBV vaccine strains. A recombination analysis of the S gene showed that the new isolate evolved from the IBV BJ strain and the KM91 vaccine strain. An animal challenge experiment showed a mortality of 60 to 80% in early-age chickens by different inoculation routes. Pathological examinations of the kidneys revealed inflammation, distention with uric acid deposits, and tubular degeneration. It indicated that the CK/CH/XDC-2/2013 isolate has robust kidney tissue tropism, and new nephropathogenic IBV strains are continuously evolving in China.

Molecular characterization of recent Iranian infectious bronchitis virus isolates based on S2 protein gene

Background: Avian infectious bronchitis (IB), with avianinfectious bronchitis virus (IBV) as the causing agent, is a ubiquitous endemicdisease of the chicken with devastating effects on its industry. A viralmembrane surface protein called S notonly induces neutralizing antibodies but also plays an important role in virusbinding and entry to host cells. Technically, S1 protein gene sequencing alsohelps greatly in IBV genotyping. OBJECTIVES: The aim of this study wasto characterize Iranian IBV based on S2 gene. METHODS: After RT-PCRamplification, the S2 gene of nine Iranian IBV isolates were sequenced and thencompared with reference strains. RESULTS: The isolates were classifiedinto genotype I as Massachusetts like IB Vs, genotype VII which clustered intotwo branches, VIIa (IS-1494 like IB viruses), and VIIb, and was related to QX-like viruses and Genotype VIII as 793/B like IBVs. CONCLUSIONS: As faras we know, this is the first S2-based classification study on Iranian IBVisolates providing a firm experimental basis to correlate with genotypiccharacterization

Full genome sequence analysis of a newly emerged QX-like infectious bronchitis virus from Sudan reveals distinct spots of recombination

Infectious bronchitis virus (IBV) infection continues to cause economically important diseases in poultry while different geno- and serotypes continue to circulate globally. Two infectious bronchitis viruses (IBV) were isolated from chickens with respiratory disease in Sudan. Sequence analysis of the hypervariable regions of the S1 gene revealed a close relation to the QX-like genotype which has not been detected in Sudan before. Whole genome analysis of IBV/Ck/Sudan/AR251–15/2014 isolate by next generation sequencing revealed a genome size of 27,646 nucleotides harbouring 13 open reading frames: 5′-1a-1b-S-3a-3b-E-M-4b-4c-5a-5b-N-6b-3′. Highest nucleotide sequence identity of 93% for the whole genome was found with the Chinese IBV strain Ck/CH/LHLJ/140906, the Italian IBV isolate ITA/90254/2005 and the 4/91 vaccine strain. Phylogenetic analysis of the S1 gene revealed that the IBV/Ck/Sudan/AR251–15/2014 isolate clustered together with viruses of the GI-19 lineage. Recombination analysis gave evidence for distinct patterns of origin of RNA in the Sudanese isolate in multiple genes. Several sites of recombination were scattered throughout the genome suggesting that the Sudan-QX-like strain emerged as a unique recombinant from multiple recombination events of parental viruses from 4/91, H120 and ITA/90254/2005 genotypes. The Sudanese QX-like isolate is plausibly genetically different from IBV strains previously reported in Africa and elsewhere.

Pathogenicity of virulent infectious bronchitis virus isolate YN on hen ovary and oviduct

Avian infectious bronchitis is an economically important poultry disease caused by avian infectious bronchitis virus (IBV). IBV isolate YN is a virulent strain, which is genetically similar to most of the prevalent strains in China. In this study, 21-day-old commercial laying hens were infected with IBV strain YN. The damaging effects of the virus on the reproductive organs were evaluated with clinical observations, gross autopsy and histopathological examinations during the 100-day monitoring period post infection. IBV strain YN infection caused a death rate of 40.5%. Microscopic lesions were observed on the ovary post-infection, but were restricted to the acute infection period. The pathological damage to the cystic oviducts were observed throughout the surveillance period. This study provides detailed information on the pathological changes in the hen ovary and oviduct after challenge with IBV strain YN, which could provide a better understanding about the pathogenicity of IBV.

Phylogenetic analysis and full-length characterization of S1 gene of IS-1494 (Variant 2) like infectious bronchitis virus isolates, Iran, 2015

Infectious bronchitis virus (IBV), a major pathogen of commercial poultry flocks, circulates in the form of different genotypes. Three IB viruses were isolated from broiler chickens showing respiratory and renal lesions. The isolates were characterized by reverse transcriptase polymerase chain reaction and sequence analysis of the Full-length of the S1. Three isolates were belonged to Variant 2 like (IS/1494 like) IBV genotype. Phylogenetic analysis showed that Variant 2 like isolates formed two clusters and the Iranian and Iraqi isolates were included in the cluster II. Cluster I composed of Israeli, Egyptian and Turkish Variant 2 like IBV Isolates. Three hyper variable regions (HVR) of S1 were determined. The Most variation was seen in HVR2. The findings emphasize the importance of continuous monitoring of IBV, in addition to adjust diagnostic methods, molecular epidemiological studies, development and use of vaccines which are adapted to the changing disease scenario.

Isolation of a novel serotype strain of infectious bronchitis virus ZZ2004 from ducks in China.

In chickens, the infectious bronchitis virus (IBV) often causes respiratory distress, a decrease in egg production, poor egg quality, and occasional nephritis. However, ZZ2004, a Chinese isolate of IBV, was obtained from ducks with clinical growth suppression and mild respiratory symptoms that had been reared with chickens in the central region of China. Virus isolation, virus neutralization testing, and RT-PCR were employed to identify the causative pathogen, while sequence alignment was used to analyze gene variations of the S1 subunit and M genes. The results showed that the ducks were infected with IBV due to the emergence of a dwarfing phenotype and the death of embryos between 48 and 144 h post-inoculation. RT-PCR also confirmed the presence of the expected fragment sizes of the S1 subunit and M genes by RT-PCR. Meanwhile, the results of the virus neutralization test indicated that the strains of JX/99/01, GD, SAIBK, LDT3 showed cross-reactivity with the ZZ2004 isolate, and hardly any cross-neutralization of IBV ZZ2004 was observed with the strains of M41, H120, Gray, Holte, or Aust-T. Phylogenetic analysis suggested that there were large differences between ZZ2004 and other IBV reference strains on the S1 subunit. Meanwhile, homologies in the nucleotide and amino acid sequences of the M gene of IBV ZZ2004 were 86.9–92.0 % and 91.1–93.9 %, respectively, compared with 35 other IBV reference strains derived from different regions. This result revealed that there were conspicuous variations among the selected strains. Furthermore, the results showed that the prevalent strains of IBV in ducks had no antigen homology with the vaccine strains widely used in China except the LDT3-strain, making it urgent to explore and develop new IBV vaccines.