Avian infectious bronchitis is a contagious viral disease, caused by avian infectious bronchitis virus (IBV), that leads to severe losses in the poultry industry all over the world. Since the 1950s, IBV has circulated in the Middle East and North Africa, and no tangible evidence has shown any effects of measures taken to control its spread or evolution. Furthermore, new IBV variants are continually discovered. Although several genetic studies on IBV have been conducted, many IBV strains from this region have either been misclassified or remain unclassified. The genotype 23 (GI-23) variant emerged and has prevailed in the Middle East by continuously evolving through inter-and/or intra-genotypic recombination. The GI-23 genotype is currently enzootic throughout Europe and Asia. Although many studies of protection against the circulating strains have been conducted, they have not been standardized according to regulatory requirements. In this review, we provide an overview of the evolution and genetic diversity of IBV genotypes and a genetic classification of IBV strains, with a focus on the GI-23 genotype. The high prevalence of IBV GI-23 strains necessitates the adoption of vaccination schemes using GI-23-based vaccines.

Infectious bronchitis virus GI-23 lineage, although described approximately two decades ago in the Middle East, has recently drawn remarkable attention and is considered an “emerging” lineage due to its current spread to several other regions, including Europe. Despite the relevance, no comprehensive studies are available investigating its epidemiologic and evolutionary pattern. The present phylodynamic study was designed to fill this gap, benefitting from a collection of freely available GI-23 sequences and ad-hoc generated European ones. After a relatively ancient origin in the Middle East, likely in the first half of the previous century, GI-23 circulated largely undetected or underdiagnosed for a long time in this region, likely causing little damage, potentially because of low virulence coupled with limited development of avian industry in the considered years and regions and insufficient diagnostic activity. The following development of the poultry industry and spread to other countries led to a progressive but slow increase of viral population size between the late ‘90s and 2010. An increase in viral virulence could also be hypothesized. Of note, a big recombinant cluster, likely originating in the Middle East but spreading thereafter, especially to Europe through Turkey, demonstrated a much-marked increase in viral population size compared to previously circulating variants. The extensive available GI-23 sequence datasets allowed to demonstrate several potential epidemiological links among African, Asian, and European countries, not described for other IBV lineages. However, differently from previously investigated IBV lineages, its spread appears to primarily involve neighbouring countries and those with strong economic and political relationships. It could thus be speculated that frequent effective contacts among locations are necessary for efficient strain transmission. Some countries appear to play a major role as a “bridge” among less related locations, being Turkey the most relevant example. The role of vaccination in controlling the viral population was also tentatively evaluated. However, despite some evidence suggesting such an effect, the bias in sequence and data availability and the variability in the applied vaccination protocols prevent robust conclusions and warrant further investigations.

Turkey coronavirus (TCoV) is a Gammacoronavirus causing acute contagious enteritis in young turkeys, leading to impaired growth, low feed conversion, and increased mortality. The TCoV infections, in association/combination with other enteropathogenic viruses, bacteria & protozoa, are associated with poult enteritis-mortality syndrome (PEMS) in turkeys of 1-4 weeks age. In this review, classification & genotyping of TCoV, the implications of its recombination, and challenges to develop efficient vaccines against it are discussed. Though TCoV is monophyletic with infectious bronchitis virus (IBV) with a sequence similarity of ≥86, however a classification scheme gathering all avian coronaviruses (ACoVs) is not established. Based on the N gene, ACoVs are classified into five clades. Clades 1 & 2 (chickens), Clade 3 (pigeon) Clade 4 (duck), and Clade 5 (goose). The Spike (S) gene of ACoVs has shown exceptional lability of being easily switched with multiple recombination events suggesting that TCoV may be an IBV recombinant. Recombination events altered the pathogenicity, host specificity, and tissue tropism of TCoVs. Attempts to develop attenuated, inactivated, DNA, and virus-vectored vaccines are ongoing. Experimentally, the attenuated TCoV strains induced strong humoral and cellular immune responses and completely protected against the homologous challenge but not heterologous TCoV challenge. Meanwhile, genetically engineered vaccines, either DNA or virus vectored vaccines, are limited with either late induction of a protective immune response and/or inability of the elicited antibody to neutralize virus infection and protect against virus challenge. Future research should focus on improving vaccine efficiency against TCoVs by developing more immunogenic vaccines, determining the appropriate dosing regimens, and include potent adjuvants.

The coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), is the third emerging human coronavirus, leading to fatal respiratory distress and pneumonia. The disease originated in December 2019 in Wuhan City, Hubei province, China. As of 23 November 2021, over 258 million cases and 5.1 million deaths have been reported in more than 222 countries and territories worldwide. The COVID-19 is under biological hazards group 4 of high risk of spreading to the community with the potential to overwhelm the health system, especially in resource limited countries. Transmission of COVID-19 within healthcare and non-healthcare facilities has been recorded. Therefore, several authorities such as the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), and other global partners issued guidance to mitigate the COVID-19 pandemic in these facilities. A global emergency due to the COVID-19 pandemic requires various studies of mitigation measures and risk assessment. The Failure Mode and Effects Analysis (FMEA) was used as a tool for risk assessment in healthcare and clinical fields that assigns a numerical value to each risk associated with failure. Therefore, in this review, the FMEA procedure was used to evaluate the COVID-19 risks and risk groups in health care and non-healthcare workplaces. Proposed mitigation measures and risk ranking tools were also summarized. The COVID-19 transmission risk should be theoretically and practically reduced by applying the best hygienic practices. However, providing safe work practices must be improved for infection control measures in healthcare and non-healthcare workplaces. Additionally, it is recommended to reassess the risk of COVID-19 infection from time to time, especially after vaccines availability.