Characterization of orthoreoviruses isolated from American crow (Corvus brachyrhynchos) winter mortality events in eastern Canada
Notice bibliographique
Résumé
A putative reovirus has been isolated from mortality events in American crows,\nof eastern Canada. The purpose of this research is to establish biological characteristics\nof this American crow reovirus, its genetic relatedness to other reoviruses and to\ndetermine its pathogenic significance for commercial poultry. The growth properties of\nthe isolates were assessed in VERO and QM 5 cell lines, the partial S2 and S4 genome\nsegments were sequenced and phylogenetic analysis were performed and a\npathogenicity trial in SPF chickens was done.\nTwenty-six suspect orthoreoviruses (2 from PEI and 24 from Ontario) were\nisolated from winter mortality events affecting American crow in eastern Canada.\nFourteen isolates exhibiting CPE were analyzed (2 from PEI and 12 from Ontario)\nusing avian orthoreovirus genome segment-specific primers for segments S2 and S4, in\na conventional one-step RT-PCR assay. Results confirmed that 14 of the 26 viruses\nwere from the family Reoviridae, 100 % of the PEI isolates (2/2) and 91.67% of the\nOntario isolates (11/12) were avian orthoreoviruses; and 1/24 (4.2%) of the Ontario\nisolates was a rotavirus. This is the first report of isolation and accurate identification of\navian orthoreoviruses from American crow mortality events supporting the etiological\nrole of American crow orthoreoviruses in the winter crow mortality syndrome.\nAnalysis of the S2 sequences discovered that the PEI and Ontario isolates had\nsequence similarity to avian orthoreovirus isolates of commercial poultry. Analysis of\nthe S4 sequences revealed that both isolates had the highest sequence similarity with\nTvärminne avian virus (TVAV). S2 and S4 genome segments of the two isolates had\n99.8% and 95.2% sequence similarity respectively with each other. Phylogenetic analysis of S2 sequences placed these viruses in the same cluster\nwith avian orthoreoviruses of commercial poultry. However, the S4 phylogenetics\nestablished that American crow orthoreovirus isolates have a closer relationship to the\nTVAV. These American crow isolates are genetically distinct from most other avianorigin\northoreoviruses and have a reassorted S4 segment which has been acquired from\nthe TVAV.\nIn the experimental infection of SPF chickens, American crow orthoreovirus\nisolates crossed the species barrier resulted in clinical disease with high morbidity and\nlow mortality producing enteric lesions in the lower gastrointestinal tract from\nventriculus to jejunum.\nThe sensitivity and specificity of S4 genome segment specific conventional onestep\nRT-PCR assay for American crow orthoreovirus was assessed. The assay had a\n100% analytical specificity, however virus isolation in VERO cells had higher detection\nlimit than the RT-PCR. Application of this assay for the detection of American crow\northoreovirus in intestinal tissue confirmed 9 positives out of 44 samples tested. In\naddition to the 9 RT-PCR positives, another 5 samples of the 44 produced characteristic\nCPE in VERO cells. Infected first passage VERO cell lysate of these 5 samples yielded\northoreovirus S4 segment specific PCR band confirming the CPE observed in VERO\ncells was due to American crow orthoreovirus. This RT-PCR assay is useful as an\nancillary diagnostic tool for routine detection of avian orthoreoviruses.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».