1,721,016 research outputs found
Molecular classification of IBD: new diagnostic tools and epidemiological updates from the Middle East
No full textEpidemiologia molecolare del virus della bronchite infettiva: approfondimenti sulle interazioni tra evoluzione virale, diagnosi e controllo
Full text linkIl virus della bronchite infettiva (IBV) è responsabile di una sintomatologia respiratoria, renale e riproduttiva in polli di tutte le età e categorie produttive, che ne fa uno dei patogeni dal maggior impatto economico e sanitario sull’avicoltura mondiale. La notevole variabilità genetica di IBV, legata alla sua natura di virus a RNA, esita nell’emergenza e nella cocircolazione di innumerevoli varianti genetiche. Questa eterogeneità ha profonde ripercussioni su questioni pratiche quali il controllo della malattia, perseguito tramite elevati standard di biosicurezza uniti alla vaccinazione di massa, e la sua diagnosi, basata principalmente su metodiche molecolari. Ciononostante, queste interazioni non vanno considerate come unidirezionali, in quanto sia le misure di controllo che le procedure diagnostiche adottate possono avere profondi effetti, diretti o indiretti, sull’evoluzione di IBV, oltre che le une sulle altre.
Questo lavoro riporta i risultati di numerosi studi che esplorano diversi aspetti dell’epidemiologia di IBV e permettono di approfondire le interconnessioni tra i tre argomenti sopraccitati. Se alcune di esse, come gli effetti della variabilità genetica sull’efficacia dei protocolli vaccinali, risultano ben caratterizzate, altre sono più oscure e spesso trascurate. Le evidenze di campo e sperimentali qui raccolte, unite a una revisione dello stato dell’arte, sono state usate come base per un approccio olistico allo studio di IBV, la cui adozione avvantaggerebbe non solo la nostra comprensione di questo patogeno, ma anche le attuali possibilità di controllo.Infectious bronchitis virus (IBV) is one of the most impactful pathogens for the worldwide poultry industry, being responsible of respiratory, renal and reproductive symptoms in chickens of every age and productive type. Being an RNA virus, IBV is featured by a remarkable genetic variability, resulting in the emergence and cocirculation of a plethora of genetic variants. This heterogeneity has significant practical repercussions on its control, which is pursued through high standards of biosecurity along with mass vaccination, and diagnosis, mainly achieved with the use of molecular methods. However, this interplay should not be considered as unidirectional. In fact, the adopted control measures and diagnostic procedures may have profound effects, either direct or indirect, on IBV evolution and also on each other.
This work reports the results of several studies that explore different aspects of IBV epidemiology and provide novel insights on the interactions between these three subjects. While some of them, like the way in which genetic variability drives the choice of vaccination protocols, are fairly well-known, others are less evident and often overlooked. The collected field and experimental evidence, along with a review of the current literature, served as the basis of a comprehensive approach towards the study of IBV, whose adoption would benefit not only the knowledge of this challenging pathogen, but also our control capabilities
A comprehensive view of the infectious bursal disease virus epidemiological landscape in Africa
Full text linkInfectious bursal disease virus in Western Europe: the rise of reassortant strains as the dominant field threat
Full text linkInfectious bursal disease virus (IBDV) is a highly contagious birnavirus causing a burdensome immunosuppressive disease in chickens. IBDV features a remarkable antigenic, pathogenic and genetic heterogeneity, with significant implications on disease manifestation, control measures and diagnostic approaches. The recent proposals of comprehensive phylogenetic classification systems offered the ideal platform for large-scale molecular surveys, which are crucial to gather epidemiological data and inform control efforts. In this study, the IBDV scenario was investigated in most of Western Europe by considering the results of diagnostic activities performed internationally throughout 2021. In total, 470 bursal samples from nine different countries were analysed by RT-PCR targeting the VP2. When a field virus was identified, the VP1 was also characterized. Most of the 132 detected field viruses were highly homologous reassortants featuring a very virulent-like VP2 and a classical-like VP1 (genotype A3B1). Despite emerging recently, these reassortants were already signalled in several countries in North-Western Europe and associated with subclinical infections. Here, we report their further spread in the region, where they currently represent the dominant field threat. Two other IBDV types were found, one in Italy, where all the identified viruses clustered in a clade of the A3B1 genotype previously reported only in Russia and the Middle East, and the other in Portugal, where the recently characterized A9B1 genotype was confirmed to circulate. The obtained data suggest the recent occurrence of a major shift in the Western European epidemiological landscape of IBDV, stressing the importance of steady monitoring and sharing of information among different countries and laboratories
Isolation and pathogenicity assessment of Egyptian novel variant infectious bursal disease virus strains
No full textINFECTIOUS BRONCHITIS VIRUS AND AVIAN METAPNEUMOVIRUS IN A RURAL DEALER FARM: SPREADING DYNAMICS AND GENETIC VARIABILITY
No full textEffect of changes of vaccination strategies on IBV epidemiology, diagnosis and control: an Italian retrospective study
Full text link: 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
Retrospective Study Reveals Decades of PCV4 Circulation in Spain
Full text linkPorcine circovirus 4 (PCV4) was first identified in China in 2019 and retrospectively traced back to 2008. However, unlike other circoviruses, its distribution appeared to be largely confined to Asian countries until recent reports from Spain and the United States. This study aims to enhance knowledge of the past and present circulation of PCV4 in non-Asian countries, particularly in Spain and in wild boars, where it was previously detected at a significant prevalence. By genetically characterizing the strains, the contextualization within both national and international epidemiological frameworks was attempted. A total of 302 lymph node samples were tested, with 62 testing positives by quantitative real-time polymerase chain reaction (qPCR), predominantly from the 2011 to 2015 period, although five positives were detected in the 2022–2024. Complete open reading frame 2 (ORF2) sequences were obtained from 10 strains. Phylogenetic analysis revealed two major clusters: one comprising only Chinese sequences and another containing strains from multiple continents, including Spain and the United States. The Spanish strains formed a distinct monophyletic clade whose introduction in the country was estimated through phylodynamic analyses around 2000, suggesting long-term undetected circulation. Within Spain, a progressive geographical spread and strain exchange between wild boars and outdoor reared domestic pigs could be inferred. On the other hand, the lack of detection in intensively raised pigs, at least in Europe, remains unclear. The present findings extend the current knowledge of PCV4 history outside Asia and challenge the paradigm of a recent international spreading. Recognizing the current uncertainties in PCV4’s international distribution and epidemiology, further efforts are needed, including the use of archived samples in diagnostic activities as well as the sharing of negative results
Piccoli cambiamenti, grandi benefici: indagine dell’effetto di differenti strategie vaccinali sull’epidemiologia molecolare del virus della Bronchite infettiva e del Metapneumovirus aviare in Grecia
No full textSynbiotic supplementation versus AGPs in broilers: the impact on caecal bacterial community structure, gut health and performance.
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