病毒感染与致病 ySis of ce Death Cytopathic effect Inclusion bod Severe disease derate ransformation ness Cell dysfunction Mild illness Viral multiplication Infection without visible without change clinical illness Exposure Exposure without cell without entry infectionCytopathic effect Inclusion body Cell transformation Cell dysfunction Severe disease Moderate illness Mild illness Exposure without cell entry Exposure without infection Infection without clinical illness Viral multiplication without visible change Lysis of cell Death Clinical Subclinical 病毒感染与致病