O型FMDV持续感染牛体内的病毒分布特征OA

Persistent infection with the Foot-and-Mouth Disease Virus(FMDV)in cattle is a current challenge in the prevention and control of Foot-and-Mouth Disease(FMD).In this study,cattle that had undergone post-vaccination challenge protection tests under laboratory conditions were used as the experimental animal model,under laboratory conditions,cattle that had undergone post-vaccination challenge protection tests were used as the experimental animal model.Individuals that showed no clinical symptoms 28 days post-challenge but tested positive for viral nucleic acid in oropharyngeal(O/P)fluid were selected as subjects foto investigater studying persistent infection.The distribution characteristics of FMDV in various tissues of persistently infected cattle werewas systematically ana-lyzed using quantitative real-time PCR(qRT-PCR)to detect viral nucleic acid load(Ct value)in tis-sues,Haematoxylin and Eosin staining to observe histopathological changes,and immunohistochemical staining to localize viral antigens.The qRT-PCR results revealedshowed that FMDV distribution in persistently infected cattle exhibited tissue specificity,exhibits tissue specificity,with viral nucleic acids predominantly enriched in the palatine tonsils,nasopharyngeal tonsils,and O/P tissues.The re-sults from H&E staining and immunohistochemical staining showed that pathological changes such as partial lymphocyte necrosis and hemorrhage were observed in the tonsils and O/P tissues,along with weakly positive signals for viral antigens in these tissues.