Analysis of avian disease transmission risk and prevention measures in China

Many zoonotic diseases are found in wild animals and present a serious risk to human health, in particularly the virus carried by birds flying freely around the world is hard to control. There are three main bird migration routes which cover the most areas of China. It is important to investigate and fully understand the types of avian transmitted diseases in key areas on the bird migration routines and its impacts on both birds and human health. However, no literature is available in how about the risk of virus carried by migrating birds, and how to predict and reduce this risk of virus spreading to human being so far. In this paper, we first reviewed the main pathogen types carried by birds, including coronaviruses, influenza viruses, parasites, Newcastle disease virus (NDV), etc., and then discussed the spread risk of avian viruses to human being and animals in key areas of biosafety prevention. We also analyzed and discussed the risk of cross-spread of diseases among different bird species in nature reserves located on bird migration routes which provide sufficient food sources for migratory birds and attract numerous birds. Diseases transmitted by wild birds pose a serious threat to poultry farms, where high density of poultry may become avian influenza virus (AIV) reservoirs, cause a risk of avian influenza outbreaks. Airports are mostly built in suburban areas or remote areas with good ecological environment. There are important transit places for bird migration and densely populated areas, which have serious risk of disease transmission. Finally, this paper puts forward the following prevention suggestions from three aspects. First, establish and improve the monitoring and prediction mechanism of migratory birds, and use laser technology to prevent contact between wild birds and poultry. Second, examine and identify virus types carried by birds in their habitats and carry out vaccination. Third, protect the ecological environment of bird habitat, and keep wild birds in their natural habitat, so as to reduce the contact between wild birds and human and poultry, and thus reduce the risk of virus transmission.

Effect of changes of vaccination strategies on IBV epidemiology, diagnosis and control: an Italian retrospective study

Infectious bronchitis virus (IBV) is among the most impactful poultry pathogens, whose control, based on biosecurity and routine vaccination, is hampered by the existence of countless genetic variants sharing poor cross-protection. A retrospective study was conducted on IBV positive samples collected in Italian broiler farms from 2012 to 2019. In 2015, the adopted vaccination protocol shifted from a Mass and 793B-based vaccines to the administration of Mass and QX vaccines, allowing to study how changes in vaccination strategies may affect IBV epidemiology, control and diagnosis in the field. The most frequently detected lineages were QX (70.3%), 793B (15.8%) and Mass (11.9%). The relative frequencies of QX and 793B detections remained stable throughout the study, while Mass detections significantly increased after the vaccination change. Rather than to an actual growth of Mass population size, this finding may be attributable to different vaccine interactions, with Mass strains being more frequently concealed by 793B vaccines than by QX ones. Based on the obtained results, the two vaccination protocols appear to be similarly effective in fighting IB outbreaks, which in the last decade have been caused primarily by QX field strains in Italy. These results indicate that vaccination strategies may significantly affect IBV epidemiology and diagnosis, and should therefore be considered when choosing and interpreting diagnostic assays and planning control measures.

Does Avian Coronavirus Co-Circulate with Avian Paramyxovirus and Avian Influenza Virus in Wild Ducks in Siberia?

Avian coronaviruses (ACoV) have been shown to be highly prevalent in wild bird populations. More work on avian coronavirus detection and diversity estimation is needed for the breeding territories of migrating birds, where the high diversity and high prevalence of Orthomyxoviridae and Paramyxoviridae have already been shown in wild birds. In order to detect ACoV RNA, we conducted PCR diagnostics of cloacal swab samples from birds, which we monitored during avian influenza A virus surveillance activities. Samples from two distant Asian regions of Russia (Sakhalin region and Novosibirsk region) were tested. Amplified fragments of the RNA-dependent RNA-polymerase (RdRp) of positive samples were partially sequenced to determine the species of Coronaviridae represented. The study revealed a high presence of ACoV among wild birds in Russia. Moreover, there was a high presence of birds co-infected with avian coronavirus, avian influenza virus, and avian paramyxovirus. We found one case of triple co-infection in a Northern Pintail (Anas acuta). Phylogenetic analysis revealed the circulation of a Gammacoronavirus species. A Deltacoronavirus species was not detected, which supports the data regarding the low prevalence of deltacoronaviruses among surveyed bird species.

Cloning, expression and identification of truncated spike gene of IBV (Sf200) and chicken granulocyte- macrophage colony stimulating factor (GM-CSF)

The aim of this study was to clone, express and identify the truncated S1 gene of nephrotropic infectious bronchitis virus (IBV) and granulocyte-monocyte colony stimulating factor (GM-CSF) of chicken. Firstly, two genes were amplified by polymerase chain reaction (PCR) and cloned into pMD18-T vector. The truncated S1 gene designated as Sf200 containing five antigenic sites of S1 glycoprotein on amino acid residues (aa) 24-61, (aa) 291-398 and (aa) 497-543 and GM-CSF were then amplified from the respective recombinant pMD18-T plasmids and cloned into pET-32a (+) vector resulting pET-Sf200, pET-GM which were identified by restriction enzyme digestion and sequencing analysis. The in vitro expression of truncated Sf200 and GM-CSF constructs were later expressed in E. coli BL21 with a molecular mass of approximately 38 kDa and 29 kDa respectively as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. Polyclonal antibodies were developed by injecting E. coli expressed Sf200 and GM-CSF into the SPF mice and were used to identify the recombinant proteins by Western blot analysis. These findings indicated that the polyclonal antibodies produced in mice could be used to detect the recombinant truncated Sf200 and GM-CSF and vice versa.

Isolation, identification, and S1 gene sequencing of two strains of Avian Infectious bronchitis virus

Objective: Epidemiology and genetic variations of the infectious bronchitis virus(IBV) in Fujian province were studied. Method: Two strains of virus isolated from the diseased chickens in Fujian in 2021 were identified by chicken embryo pathogenicity test, electron microscope observation, and RT-PCR. S1 genes of the isolates were cloned, sequenced, and analyzed using biological software. Result: The two IBV strains were code named FJ-NP01 and FJ-FZ01. The full length of S1 of FJ-NP01 was 1 629 nt encoding 543 amino acids, and that of FJ-FZ01, 1 620 nt encoding 540 amino acids. The S1 gene cleavage site of FJ-FZ01 was HRRRR, same as all reference strains of genotype I branch;while that of FJ-NP01 HRRKR differed from the reported site of IBV isolated from genotype IV but same as that of TC07-2 reference strain of genotype VI. The homology of nucleotide and amino acid between the two isolates was 83.2% and 79.6%, respectively, but merely 75.7%-76.3%and 77.1%-83.5% with the Mass-type conventional vaccines H120 and H52, respectively. Further analysis showed that FJ-NP01was from a recombination event between CK CH GD LZ12-4 and L-1148, the homology of nucleotide acid between 1438-1506 nt of FJ-NP01 with CK CH GD LZ12-4 was 97%, and 95.9% between the other nucleotide acid of S1 gene with L-1148. Conclusion: It appeared that the IBV epidemic experienced in the province was complex in nature and that the existing Mass vaccines would not provide sufficient immune protection to deter the spread.

Preparation and identification of broad-spectrum monoclonal antibodies against N protein of avian infectious bronchitis virus

[Objective] To prepare broad-spectrum monoclonal antibody against N protein of avian infectious bronchitis virus (IBV), so as to lay a foundation for identifying conservative domain epitope of N protein and establish a universal IBV detection method. [Method] N protein of GX-YL5, a representative strain of IBV dominant serotype in Guangxi, was expressed in prokaryote. BALB/c mice were immunized with the purified protein. After the serum titer of the immunized mice reached 104 or more, the splenocytes were fused with SP2/0 myeloma cells. After screening by indirect ELISA, monoclonal antibody was prepared by ascites-induced method. Western blotting, IFA and indirect ELISA were used to identify the titer, subtype, reaction specificity and cross-reaction spectrum. And the prepared monoclonal antibody was used for immunohistochemical detection. And the prepared monoclonal antibody was used to detect the IBV in the trachea and kidney tissues of SPF chickens artificially infected with 4 representative IBV variants (GX-N130048, GX-N160421, GX-QZ171023 and GX-QZ170728). [Result] The prepared monoclonal antibody N2D5 had a titer greater than 217 and its subtype was IgG2b. The Western blotting and IFA results showed that the monoclonal antibody N2D5 only reacted with IBV, and were negative with Newcastle disease virus (NDV), infectious laryngotracheitis virus (ILTV), avian metapneumovirus (aMPV), infectious bursal disease virus (IBDV), avian leukosis virus (ALV) and Marek's disease virus (MDV). Monoclonal antibody N2D5 reacted with many genotypes in China and all 7 serotypes of IBV currently prevalent in Guangxi, including commonly used standard strains, vaccine strains and field strains. Immunohistochemistry showed that the virus signals could be detected in the trachea and kidney tissues of SPF chickens at different time after artificial infection of 3 representative IBV strains from chicken and 1 isolated strain from duck, which further proved its broad spectrum. [Conclusion] The monoclonal antibody N2D5 of IBV prepared based on hybridoma technology belongs to the IgG2b subtype. It has the characteristics of high specificity, wide response spectrum and strong binding ability with IBV. It can be used as a specific diagnostic antibody for clinical diagnosis of IBV and the study of virus distribution.

Pathogenicity analysis of one avian infectious bronchitis virus stain isolated from Shanxi

In order to perform the isolation of avian infectious bronchitis virus (IBV) and study the pathogenicity of IBV isolate, the RT-PCR was used to detect nucleic acid extracted from a clinical sample of chickens, which were suspected to be infected with infectious bronchitis virus (IBV) and provided by a farmer in Yuncheng, Shanxi province. And the sample was detected as IBV positive by RT-PCR. Then 9-11-day-old SPF chicken embryonated eggs were inoculated with the sample filtered from the grinding fluid, and the obtained allantoic fluid was blindly passed by three generations (F3) and was also tested as IBV positive;The F11 generation passaged in embryonated eggs caused typical "dwarf embryo" lesions to SPF chicken embryonated eggs, and induced the loss of cilia in tracheal rings. The results showed that an IBV strain was isolated and named as YC181031. The S1 gene amplification and sequencing analysis showed that YC181031 strain belonged to IBV GI-22 genotype, which is also nephropathogenic type IBV. Seven-day-old SPF chicks were used to test the pathogenicity of the isolate. The results showed that several clinical symptoms were showed in chicks infected with YC181031, such as breathing with difficulty, depression, excreting watery droppings and death. The mortality of infected chicks was 20%. Typical pathological changes such as enlargement of kidney and urate deposition in the kidney were observed in infected chicks. The immunohistochemical assay and viral load detection were performed for the tissue samples from infected and dead chicks. The tissue lesions and distribution of virus were observed in the kidney, trachea, lung, glandular stomach, spleen and liver samples of infected chicks. RT-PCR detection of pharyngeal anal swabs showed that the virus shedding by infected chicks could be continuously detected within 14 days of the test period;The viral loads of various tissues were detected by RT-qPCR and the results showed that the viral load from high to low was kidney, trachea, lung, stomach, spleen and liver. The viral load of kidney was significantly higher than that of other tissues (P < 0.05).In this study, the pathogenicity characteristics of GI-22 genotype strain were systematically studied for the first time, providing a reference for the prevention and treatment of the disease.

Identification and Comparison of the Sialic Acid-Binding Domain Characteristics of Avian Coronavirus Infectious Bronchitis Virus Spike Protein.

Infectious bronchitis virus (IBV) infections are initiated by the transmembrane spike (S) glycoprotein, which binds to host factors and fuses the viral and cell membranes. The N-terminal domain of the S1 subunit of IBV S protein binds to sialic acids, but the precise location of the sialic acid binding domain (SABD) and the role of the SABD in IBV-infected chickens remain unclear. Here, we identify the S1 N-terminal amino acid (aa) residues 19 to 227 (209 aa total) of IBV strains SD (GI-19) and GD (GI-7), and the corresponding region of M41 (GI-1), as the minimal SABD using truncated protein histochemistry and neuraminidase assays. Both α-2,3- and α-2,6-linked sialic acids on the surfaces of CEK cells can be used as attachment receptors by IBV, leading to increased infection efficiency. However, 9-O acetylation of the sialic acid glycerol side chain inhibits IBV S1 and SABD protein binding. We further constructed recombinant strains in which the S1 gene or the SABD in the GD and SD genomes were replaced with the corresponding region from M41 by reverse genetics. Infecting chickens with these viruses revealed that the virulence and nephrotropism of rSDM41-S1, rSDM41-206, rGDM41-S1, and rGDM41-206 strains were decreased to various degrees compared to their parental strains. A positive sera cross-neutralization test showed that the serotypes were changed for the recombinant viruses. Our results provide insight into IBV infection of host cells that may aid vaccine design. IMPORTANCE To date, only α-2,3-linked sialic acid has been identified as a potential host binding receptor for IBV. Here, we show the minimum region constituting the sialic acid binding domain (SABD) and the binding characteristics of the S1 subunit of spike (S) protein of IBV strains SD (GI-19), GD (GI-7), and M41 (GI-1) to various sialic acids. The 9-O acetylation modification partially inhibits IBV from binding to sialic acid, while the virus can also bind to sialic acid molecules linked to host cells through an α-2,6 linkage, serving as another receptor determinant. Substitution of the putative SABD from strain M41 into strains SD and GD resulted in reduced virulence, nephrotropism, and a serotype switch. These findings suggest that sialic acid binding has diversified during the evolution of γ-coronaviruses, impacting the biological properties of IBV strains. Our results offer insight into the mechanisms by which IBV invades host cells.

The influence of dietary Salvia and lavender powders on productive performance, some physiological parameters, and immunity of broiler under stocking density stress

The purpose of this experiment was to increase poultry meat production by increasing the number of chickens reared in the same area and managing it by using medicinal herbs Salvia officinalis L and Lavandula angustifolia L. in the broiler chicken diet. 705 one-day-old chicks were randomly distributed into to7 treatments with three replicates for an area of two m2 floor system in each replicate for each treatment, during 35 days of the study. T0 negative control 75 chicks, 25 chicks for each replicate 12-13 chicks per m2 fed standard diet. T1 positive control (stocking density without supplementation)105 chicks, 35 each replicate chicks 17-18 per m2 fed standard diet. The same stocking density for T2, T3, T4, T5, and T6 have been given standard feed with supplemented herbals, salvia 0.7%, 0.9%, lavender0.7%, 0.9%, and mixed 0.7% respectively. Depending on the results, chickens reared in stress stocking density with supplementations led to higher improvement of body weight, meat production, body weight gain (BWG), feed conversion ratio(FCR g feed/g weight), production index PI, carcass weight (g) and dressing percentage, RBCs 106cells/mm3, lymphocyte%, of increasing activity of thyroid hormones T3, T4 (nmol/L) boost antibody titers of ND and IBV when compared with positive control. However, heterophil%, stress indicator H/L ratio, glucose mg/ dL and cholesterol mg/ dL significantly reduced. The results showed that adding sage and lavender plants to broiler feed is effective in improving productivity, immunity, and resistance characteristics in reducing the adverse effects of stress caused by increasing the intensity of broiler rearing in the same area.

Evaluation of Inosine-Acedoben-Dimepranol as an immunomodulator in broiler chicks vaccinated with Infectious bronchitis virus vaccine

Protecting livestock against diseases by enhancing its immunity is essential and required in poultry industry. Therefore, the aim of the present study was to evaluate the possible immunoenhancing effects of Inosine-Acedoben-Dimepranol (IAD) in broiler chicks. A total of 150 chicks were used in the present study, divided into 6 groups (25 for each) and subjected to different treatments. It has been found that IAD significantly (P 0.05) increased total leukocytic count, with increased granulocyte (neutrophils, eosinophils, basophils), lymphocyte and monocyte counts compared to control chicks. IAD significantly (P 0.05) increased total protein as a result of increased globulins in plasma when compared with those of control. IAD has been found to significantly (P 0.05) increase immune response of IB vaccine in IAD + IB vaccine-treated groups compared to control measured by ELISA. IAD exhibited antiviral effect indicated by increased survival percent of chicks challenged with virulent IB virus with survival 100% in the groups received IAD large dose plus vaccine. Data of the present study may indicate that supplying chicks with IAD in drinking water is a good recommendation in poultry industry based on its immune enhancing properties.

Detection and molecular characterization of gammacoronavirus in quail population in Iran

BACKGROUND: Gammacoronaviruses, which are single-stranded, positive-sense RNA viruses, are responsible for a wide variety of existing and emerging diseases in birds. The Gammacoronaviruses primarily infect avian hosts. OBJECTIVE(S): This study aimed to investigate the genetic diversity of Gammacoronaviruses in quail population in Iran. METHOD(S): In the period from 2016 to 2018, samples from 47 quail flocks with or without enteric signs, were collected from four provinces in Iran. RESULT(S): Gammacoronavirus was detected in samples of 4 flocks by using RT-PCR and characterized by N gene sequencing. The isolates formed a distinct group from other Gamma- coronaviruses groups CONCLUSION(S): The finding suggests the existence of a novel Gammacoronavirus circulating in quail farms. The phylogenetic relationship of the isolates concerning different sequences and geographical regions displayed complexity and diversity. The present study is the first detection of Gammacoronavirus in quail farms in Iran. Further studies are required and should include the isolation and experimental studies of Gammacoronaviruses in Iran.Copyright © 2019.

Viral diseases of poultry in Assam, India: a review

The Indian poultry market is estimated to have an annual growth rate of 8.1% as of today. However, infectious diseases in poultry pose an important constraint in the growth and development of this sector in our region. Among infectious diseases, viral diseases of poultry pose a serious threat to the poultry industry from an economic point of view. Several viral disease outbreaks have been reported by various researchers from different parts of the country. Among the common viral diseases of poultry, incidences of Newcastle disease, Avian Influenza, Fowl Pox, Infectious Bursal Disease, Marek's disease, Infectious Bronchitis, Infectious Laryngotracheitis and Inclusion Body Hepatitis are significant in Assam as well as other parts of India. Thorough epidemiological studies followed by the identification of different serotypes, pathotypes, strains, etc. by genotyping and molecular characterization of viral disease pathogens may lead to ways to control and eradicate the diseases. Importance should be given to maintaining basic preventive measures like biosecurity, farm hygiene, and proper vaccination. In a developing country like India, disease outbreaks can impact the country's economy. In this study, a brief view of the common viral disease of poultry and its diagnosis and control strategies in Assam, India is depicted. However, this review well indicates a plethora of avian diseases that have occurred over the years causing a severe impact on poultry farming as a whole.

Crystal Structures of Inhibitor-Bound Main Protease from Delta- and Gamma-Coronaviruses.

With the spread of SARS-CoV-2 throughout the globe causing the COVID-19 pandemic, the threat of zoonotic transmissions of coronaviruses (CoV) has become even more evident. As human infections have been caused by alpha- and beta-CoVs, structural characterization and inhibitor design mostly focused on these two genera. However, viruses from the delta and gamma genera also infect mammals and pose a potential zoonotic transmission threat. Here, we determined the inhibitor-bound crystal structures of the main protease (Mpro) from the delta-CoV porcine HKU15 and gamma-CoV SW1 from the beluga whale. A comparison with the apo structure of SW1 Mpro, which is also presented here, enabled the identification of structural arrangements upon inhibitor binding at the active site. The cocrystal structures reveal binding modes and interactions of two covalent inhibitors, PF-00835231 (active form of lufotrelvir) bound to HKU15, and GC376 bound to SW1 Mpro. These structures may be leveraged to target diverse coronaviruses and toward the structure-based design of pan-CoV inhibitors.

Evaluating Persistent Symptoms of SARS-CoV-2 Infection by Precision Medicine

During these two years, the SARS-CoV-2 pandemic spread fast, killing people as surely as the global war. Step by step, research revealed several aspects of this plague. Understanding the essential etio-pathological characteristics of SARS-CoV-2 infection is necessary to outline discuss and assess its pathogenic mechanism and proceed with proper viral be-haviours assessment. Coronaviruses are enveloped by positive-sense and negative-sense RNA viruses. Their characteristic is a characteristic long spike protein projecting from the surface. These viruses have an unusual huge RNA genome (that is up to 33.5 kilobases). These viruses are the largest Noroviruses;the order includes Coronaviridiae and includes the order which includes the Coronaviridae, Arteriviridneae, Mesonivirideae, and Ronivirideae families. Coronaviruses have two subfamilies, Corinaviridea Orthocoronavirinae and Torviridiae Letovirinae. The taxonomy subdivides Orthocoronavirinae Coronaviridiae into different genera, e.g., the alfa, the beta, and gamma Coronaviruses. The coronavirus virion structure of coronaviruses is spherical with a diameter of 125 nm. Copyright © 2022 Phcog.Net. All rights reserved.

Diversity of coronaviruses in wild and domestic birds in Vietnam

Objective: To investigate the genetic diversity of coronaviruses in wild and domestic birds in the bird park and live poultry markets of Ca Mau province in Vietnam in 2020. Methods: A total of 228 samples (121 from wild birds and 107 from poultry) were collected in the territory of Ca Mau province of Vietnam in 2020. The avian samples were tested for the presence of the four genera of coronaviruses using reverse transcription and nested PCR. Molecular genetic analysis using targeted NGS sequencing of RdRp gene was performed for 29 representative samples (12 samples from wild birds and 17 from poultry). Phylogenetic analysis was performed using the neighbour joininig method with 1000 bootstrap replications using MEGA X software. Results: Among wild birds, 21.5% samples were positive for the genetic material of coronaviruses and 38.3% samples were positive for coronaviruses among poultry. Genetic analysis of the partial sequence of RdRp gene from representative samples revealed that wild birds were carriers of gammacoronaviruses and deltacoronaviruses. Among poultry, three genotypes of infectious bronchitis virus (QX, Mass and Q1) were detected in chickens, with QX genotypes being predominant, and viruses of DCoV group were detected in domestic ducks. There was no detection of alphacoronaviruses or betacoronaviruses in the studied birds. Conclusions: Coronaviruses of genera Gammacoronavirus and Deltacoronavirus were detected in wild birds. A high percentage of infectious bronchitis virus was detected in poultry. Thus, there is a need for broader surveillance of coronaviruses in birds, which can be used for evaluation of diversity, evolution and distribution of coronaviruses in Vietnam. Continuous surveillance of coronaviruses circulation in wild and domestic animals is necessary for implementing strategic measures for poultry and domestic animal protection and for evaluation of possible risk of circulating coronaviruses to human health.

New Insights into Avian Infectious Bronchitis Virus in Colombia from Whole-Genome Analysis.

Infectious Bronchitis (IB) is a respiratory disease caused by a highly variable Gammacoronavirus, which generates a negative impact on poultry health worldwide. GI-11 and GI-16 lineages have been identified in South America based on Infectious Bronchitis virus (IBV) partial S1 sequences. However, full genome sequence information is limited. In this study we report, for the first time, the whole-genome sequence of IBV from Colombia. Seven IBV isolates obtained during 2012 and 2013 from farms with respiratory disease compatible with IB were selected and the complete genome sequence was obtained by NGS. According to S1 sequence phylogenetic analysis, six isolates belong to lineage GI-1 and one to lineage GVI-1. When whole genome was analyzed, five isolates were related to the vaccine strain Ma5 2016 and two showed mosaic genomes. Results from complete S1 sequence analysis provides further support for the hypothesis that GVI-1, considered a geographically confined lineage in Asia, could have originated in Colombia. Complete genome information reported in this research allow a deeper understanding of the phylogenetic evolution of variants and the recombination events between strains that are circulating worldwide, contributing to the knowledge of coronavirus in Latin America and the world.

Molecular characterization of Infectious bronchitis virus in Southwestern China for the protective efficacy evaluation of four live vaccine strains

Avian infectious bronchitis (IB) is one of the acute and highly contagious upper respiratory tract infectious diseases in poultry caused by the Infectious bronchitis virus (IBV), which significantly affects the health and development of world poultry farming industry. IBV RNA polymerase lacks a complete correctional function and is prone to gene mutation and RNA-RNA recombination during the replication process, resulting in the emergence of new serotypes, genotypes and mutant strains. The continuous generation of recombinant strains through homologous recombination between strains also complicates the prevention and control of IB. Therefore, monitoring the genetic evolutionary characteristics of circulating strains and evaluating the protective effect of commonly used vaccines against local circulating strains of IBV are the keys to preventing and controlling this disease.

Avian infectious bronchitis - control of the disease and prophylactic measures

Poultry industry is dynamically developing worldwide, and the threat from infectious viral diseases also increases. One of them is an acute, highly contagious avian infectious bronchitis (IB), caused by infectious bronchitis virus (IBV), the coronavirus of the fowl. IBV is characterized by extensive variations in the surface spike protein gene. Those genetic variations lead to rapid changes in IBV serotypes that need to be constantly monitored to assess the epidemiological situation in the field. The aim of this article was to present current knowledge and recent epidemiology, based on IBV field strains circulation. Several serotypes can be simultaneously present in a region and as they cross-protect poorly, broiler chickens can be infected more than once within their short period of life. Careful, constant monitoring is necessary to respond fast in case of new genetic IBV variants development. Some of these strains have global range, while the prevalence of others is limited to some geographical areas. Thus, the understanding the IB epidemiology, virus spread and the occurrence of individual strains allows to use the optimal vaccination schedule to limit the disease and improve the poultry production. Finaily, a good recognition of the IB problem in Central and Eastern Europe on the example of Poland as the largest European poultry producer, can be a key factor in the quickest response to emerging new IBV variants. Some practical solutions may help to introduce the similar and effective procedures also in other regions of the world with high intensity of poultry production.