Current situation, genetic relationship and control measures of infectious bronchitis virus variants circulating in African regions

Unraveling the evolutionary patterns and phylogenomics of coronaviruses: A consensus network approach

The COVID-19 pandemic emphasizes the significance of studying coronaviruses (CoVs). This study investigates the evolutionary patterns of 350 CoVs using four structural proteins (S, E, M, and N) and introduces a consensus methodology to construct a comprehensive phylogenomic network. Our clustering of CoVs into 4 genera is consistent with the current CoV classification. Additionally, we calculate network centrality measures to identify CoV strains with significant average weighted degree and betweenness centrality values, with a specific focus on RaTG13 in the beta genus and NGA/A116E7/2006 in the gamma genus. We compare the phylogenetics of CoVs using our distance-based approach and the character-based model with IQ-TREE. Both methods yield largely consistent outcomes, indicating the reliability of our consensus approach. However, it is worth mentioning that our consensus method achieves an approximate 5000-fold increase in speed compared to IQ-TREE when analyzing the data set of 350 CoVs. This improved efficiency enhances the feasibility of conducting large-scale phylogenomic studies on CoVs.

Common viral and bacterial avian respiratory infections: an updated review

Many pathogens that cause chronic diseases in birds use the respiratory tract as a primary route of infection, and respiratory disorders are the main leading source of financial losses in the poultry business. Respiratory infections are a serious problem facing the poultry sector, causing severe economic losses. Avian influenza virus, Newcastle disease virus, infectious bronchitis virus, and avian pneumovirus are particularly serious viral respiratory pathogens. Mycoplasma gallisepticum, Staphylococcus, Bordetella avium, Pasteurella multocida, Riemerella anatipestifer, Chlamydophila psittaci, and Escherichia coli have been identified as the most serious bacterial respiratory pathogens in poultry. This review gives an updated summary, incorporating the latest data, about the evidence for the circulation of widespread, economically important poultry respiratory pathogens, with special reference to possible methods for the control and prevention of these pathogens.

Unique Variants of Avian Coronaviruses from Indigenous Chickens in Kenya

The avian gamma-coronavirus infectious bronchitis virus (AvCoV, IBV; Coronaviridae family) causes upper respiratory disease associated with severe economic losses in the poultry industry worldwide. Here, we report for the first time in Kenya and the Eastern African region two novel AvCoVs, designated IBV/ck/KE/1920/A374/2017 (A374/17) and AvCoV/ck/KE/1922/A376/2017 (A376/17), inadvertently discovered using random nontargeted next-generation sequencing (NGS) of cloacal swabs collected from indigenous chickens. Despite having genome organization (5'UTR-[Rep1a/1ab-S-3a-3b-E-M-4b-4c-5a-5b-N-6b]-3'UTR), canonical conservation of essential genes and size (~27.6 kb) typical of IBVs, the Kenyan isolates do not phylogenetically cluster with any genotypes of the 37 IBV lineages and 26 unique variants (UVs). Excluding the spike gene, genome sequences of A374/17 and A376/17 are only 93.1% similar to each other and 86.7-91.4% identical to genomes of other AvCoVs. All five non-spike genes of the two isolates phylogenetically cluster together and distinctly from other IBVs and turkey coronaviruses (TCoVs), including the indigenous African GI-26 viruses, suggesting a common origin of the genome backbone of the Kenyan isolates. However, isolate A376/17 contains a TCoV-like spike (S) protein coding sequence and is most similar to Asian TCoVs (84.5-85.1%) compared to other TCoVs (75.6-78.5%), whereas isolate A374/17 contains an S1 gene sequence most similar to the globally distributed lineage GI-16 (78.4-79.5%) and the Middle Eastern lineage GI-23 (79.8-80.2%) viruses. Unanswered questions include the actual origin of the Kenyan AvCoVs, the potential pathobiological significance of their genetic variations, whether they have indeed established themselves as independent variants and subsequently spread within Kenya and to the neighboring east/central African countries that have porous live poultry trade borders, and whether the live-attenuated Mass-type (lineage GI-1)-based vaccines currently used in Kenya and most of the African countries provide protection against these genetically divergent field variants.

Novel Lineage of Infectious Bronchitis Virus from Sub-Saharan Africa Identified by Random Amplification and Next-Generation Sequencing of Viral Genome

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 strain (B1648, 92.4%) and with another study strain from Ivory Coast (D2334/12/2/13/CI, 94.6%). This study illustrates the importance of epidemiological monitoring of IBV in sub-Saharan Africa, as the area may serve as a focal point for newly emerging viral lineages.

Molecular Characterization of 4/91 Infectious Bronchitis Virus Leading to Studies of Pathogenesis and Host Responses in Laying Hens

Infectious bronchitis virus (IBV) initially establishes the infection in the respiratory tract and then spreads to other tissues depending on its virulence. During 2011–2018, the 4/91 IBV strain was isolated from poultry flocks affected by decreased egg production and quality in Eastern Canada. One of the Canadian 4/91 IBV isolates, IBV/Ck/Can/17-038913, was propagated in embryonated chicken eggs and molecularly characterized using whole genome sequencing. An in vivo study in laying hens was conducted to observe if IBV/Ck/Can/17-038913 isolate affects the egg production and quality. Hens were infected with IBV/Ck/Can/17-038913 isolate during the peak of egg lay, using a standard dose and routes maintaining uninfected controls. Oropharyngeal and cloacal swabs were collected at predetermined time points for the quantification of IBV genome loads. At 6 and 10 days post-infection, hens were euthanized to observe the lesions in various organs and collect blood and tissue samples for the quantification of antibody response and IBV genome loads, respectively. Egg production was not impacted during the first 10 days following infection. No gross lesions were observed in the tissues of the infected birds. The IBV genome was quantified in swabs, trachea, lung, proventriculus, cecal tonsils, kidney, and reproductive tissues. The serum antibody response against IBV was quantified in infected hens. In addition, histological changes, and recruitment of immune cells, such as macrophages and T cell subsets in kidney tissues, were measured. Overall, data show that IBV/Ck/Can/17-038913 isolate is not associated with egg production issues in laying hens infected at the peak of lay, while it demonstrates various tissue tropism, including kidney, where histopathological lesions and immune cell recruitments were evident.

Amachawadi R, Dash AP, Yadav MP, Prasad KS, P S, Jain AS, Shivamallu C. COVID-19 PANDEMIC: A SYSTEMATIC REVIEW ON THE CORONAVIRUSES OF ANIMALS AND SARS-CoV-2

Coronaviruses (CoVs), classified into four genera, viz., alpha-, beta-, gamma-, and Delta- CoV, represent an important group of diverse transboundary pathogens that can infect a variety of mammalian and avian species including humans, animals, poultry, and non-poultry birds. CoVs primarily infect lung and gut epithelial cells, besides monocytes and macrophages. CoVs have high mutation rates causing changes in host specificity, tissue tropism, and mode of virus excretion and transmissions. The recent CoV zoonoses are SARS, MERS, and COVID-19 that are caused by the transmission of beta-CoVs of bats to humans. Recently, reverse zoonoses of the COVID-19 virus have been detected in dogs, tigers, and minks. Beta-CoV strains also infect bovine (BCoV) and canine species (CRCoV); both these beta-CoVs might have originated from a common ancestor. Despite the high genetic similarity between BCoV, CRCoV, and HCoV-OC43, these differ in species specificity. Alpha-CoV strains infect canine (CCoV), feline (FIPV), swine (TGEV and PEDV), and humans (HCoV229E and NL63). Six coronavirus species are known to infect and cause disease in pigs, seven in human beings, and two in dogs. The high mutation rate in CoVs is attributed to error-prone 3′-5′ exoribonuclease (NSP 14), and genetic recombination to template shift by the polymerase. The present compilation describes the important features of the CoVs and diseases caused in humans, animals, and birds that are essential in surveillance of diverse pool of CoVs circulating in nature, and monitoring interspecies transmission, zoonoses, and reverse zoonoses.

Limited Cross-Protection against Infectious Bronchitis Provided by Recombinant Infectious Bronchitis Viruses Expressing Heterologous Spike Glycoproteins

Gammacoronavirus infectious bronchitis virus (IBV) causes an economically important respiratory disease of poultry. Protective immunity is associated with the major structural protein, spike (S) glycoprotein, which induces neutralising antibodies and defines the serotype. Cross-protective immunity between serotypes is limited and can be difficult to predict. In this study, the ability of two recombinant IBV vaccine candidates, BeauR-M41(S) and BeauR-4/91(S), to induce cross-protection against a third serotype, QX, was assessed. Both rIBVs are genetically based on the Beaudette genome with only the S gene derived from either M41 or 4/91, two unrelated serotypes. The use of these rIBVs allowed for the assessment of the potential of M41 and 4/91 S glycoproteins to induce cross-protective immunity against a heterologous QX challenge. The impact of the order of vaccination was also assessed. Homologous primary and secondary vaccination with BeauR-M41(S) or BeauR-4/91(S) resulted in a significant reduction of infectious QX load in the trachea at four days post-challenge, whereas heterologous primary and secondary vaccination with BeauR-M41(S) and BeauR-4/91(S) reduced viral RNA load in the conjunctiva-associated lymphoid tissue (CALT). Both homologous and heterologous vaccination regimes reduced clinical signs and birds recovered more rapidly as compared with an unvaccinated/challenge control group. Despite both rIBV BeauR-M41(S) and BeauR-4/91(S) displaying limited replication in vivo, serum titres in these vaccinated groups were higher as compared with the unvaccinated/challenge control group. This suggests that vaccination with rIBV primed the birds for a boosted humoral response to heterologous QX challenge. Collectively, vaccination with the rIBV elicited limited protection against challenge, with failure to protect against tracheal ciliostasis, clinical manifestations, and viral replication. The use of a less attenuated recombinant vector that replicates throughout the respiratory tract could be required to elicit a stronger and prolonged protective immune response.

Coronaviridae: 100,000 Years of Emergence and Reemergence

The coronavirus family (Coronaviridae) is a positive-sense single-stranded RNA, with a size of 27 kb. These viruses have a potential species specificity and interspecies transmission. The interspecies transmission of viruses from one host species to another is a major factor responsible for the majority of emerging and reemerging infections. The Coronaviridae is one of the most popular emerging viral families that threaten to the public health.

Avian Coronavirus: Case of Infectious Bronchitis Virus Pathogenesis, Diagnostic Approaches, and Phylogenetic Relationship Among Emerging Strains in Middle East and North Africa Regions

Infectious bronchitis (IB) virus (IBV) is a very dynamic and evolving virus, causing severe diseases in poultry with significant economic consequences to the poultry industry worldwide, affecting chickens of all ages and possessing a major threat to the poultry industry.

IBV is well studied worldwide; nevertheless, in Middle East and North Africa (MENA) regions, epidemiological and scientific data are poor and not updated. In spite of regular vaccination with Massachusetts (Mass) strain has been available to control IB for many decades in MENA regions, which it is most commonly used, the protection is not occurred. However, the continuity of the spread of IBV has shown the emergence of multiple variant strains due to the frequent point of mutations and recombination events in the S1 gene hypervariable regions.

All the reported IBV variants circulate in the form of several serotypes/genotypes that can be partially or poorly neutralized by current vaccines. This emergence remains a problem for the poultry industry and vaccine manufacturers. Therefore the objective of this present chapter, which is reported for the first time, aims to establish phylogenic relationship among emerging strains in MENA regions.

Comparative features of infections of two Massachusetts (Mass) infectious bronchitis virus (IBV) variants isolated from Western Canadian layer flocks

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.