Viruses and Bacteria Flashcards
Viruses with Lipid Envelope
Glycoproteins mediate attachment and entry into cells
Labile to acid, detergents, drying, heat
Spreads in respiratory droplets
Doesn’t need to kill cell to exit and spread
Steps in viral replication
Attachment and penetration
Macromolecular synthesis
Assembly of progeny virions and release from host cell
PAMPs
Double stranded RNA
Uncapped 5 prime RNA
Unmethylated CpG DNA
Cytosolic DNA
Syncytia formation and hemagglutination
Caused by enveloped viruses
Cytopathic effect
Formation of multinucleated giant cells via syncitia formation
Antigenic Shift
Occurs as a result of segmented genome of flu virus and the reassortment of the viral genomes in large animal reservoirs
Antigenic Drift
Occurs as a consequence of mutations introduced by the viral RNA dependent RNA polymerase during replication
Progression of Viral Infection
Acquisition Initiation of Infection Incubation period Replication in target tissue Virus spread Immune responses Resolution (Or persistent infection/latency)
Modes of viral transmission
Aerosols Food, Water fomites Direct contact Sexual contact zoonoses cross-placental infection of fetus Birth Blood transfusion
Viral Tropism
Cells with certain surface receptors
Cell environments permissive for infection
Cellular response to infection
Failed infection (Never occurs) Cell death (Lytic infection) Infection without cell death (non-cytopathic replication)
Host Defense against viral infection
Natural Barriers
Innate Immunity
Cell mediated immunity
Antibody response
