Pathogen and Host Flashcards
viral pathogenesis
study of how viral infection leads to disease
what methods can viruses use to go from infection to disease
- cell destruction
- immunopathogenic (alter immune system)
- change to cellular gene expression
pathogen
an organism which can cause disease
what features does a pathogen require to be classed as a pathogen
- present in all cases of the disease
2. can be cultured outside the body for multiple generations
commensal
organism which is part of the normal flora
innate immunity
non-specific e.g. skin, phagocytes
acquired immunity
specific response to antigen. immunological memory created
colonisation
microorganisms present but don’t cause disease
asymptomatic infection
someone is a carrier but is not showing symptoms
pathgenicity
ability of an organism to cause disease in a host
example symptoms
inflammation pain pyrexia tachycardia rigor increased WBC count
characteristics essential to cause disease in host
infectivity - established in host
virulence - harm in host
endotoxin
- component of gram negative bacterial cell wall
- lipopolysaccharide
- attached to microorganism
exotoxin
- released by micro-organisms
- not attached to micro-organism
enterotoxin
exotoxin which acts on the GI tract
sites of viral entry
- respiratory tract
- alimentary (digestive) tract
- urinogenital tract
- skin
- arthropod
- conjunctiva
features of acute viral infections
- localised to a specific site of the body
- rapid onset of disease
- brief period of symptoms
- resolution within days
example of how virus induces tumours
HPV - infects the cell, integrating into the cellular genome, causing a change in gene expression, which causes uncontrolled cell proliferation and tumour formation
humoral immunity
mediated by macromolecules found in extracellular fluids
- mostly bacterial infection
- involves antibodies
- acute inflammation
cell mediated immunity
does not involve antibodies, but rather involves;
- the activation of phagocytes
- antigen-specific cytotoxic T-lymphocytes
