The pathogenesis of foot-and-mouth disease I: viral pathways in cattle

In 1898, foot-and-mouth disease (FMD) earned a place in history as the first disease of animals shown to be caused by a virus. Yet, despite over a century of active investigation and elucidation of many aspects of FMD pathogenesis, critical knowledge about the virus-host interactions is still lacking. The aim of this review is to provide a comprehensive overview of FMD pathogenesis in cattle spanning from the earliest studies to recently acquired insights emphasizing works which describe animals infected by methodologies most closely resembling natural infection (predominantly aerosol or direct/indirect contact). The three basic phases of FMD pathogenesis in vivo will be dissected and characterized as: (i) pre-viraemia characterized by infection and replication at the primary replication site(s), (ii) sustained viraemia with generalization and vesiculation at secondary infection sites and (iii) post-viraemia/convalescence including resolution of clinical disease that may result in long-term persistent infection. Critical evaluation of the current status of understanding will be used to identify knowledge gaps to guide future research efforts.