viral properties and disease Flashcards
viral infection outcomes: list different outcomes of infection by viruses, acute infection, persistent infection, latent reactivating infection, slow infection, oncogenesis. Name examples of viruses that cause each type of infection
5 outcomes of viral infection
acute infection (followed by viral clearance; can cause “accidental” tissue infection with permanent damage), persistent infection (latent, slow, transforming), long incubations, oncogenesis
examples of viruses causing acute infection and clearance
colds, influenza, rhinovirus, rotavirus
examples of viruses causing acute infection and death
smallpox, dengue
examples of viruses causing acute infection and accidental pathogenesis
polio (paralysis), rubella (deafness, cataracts, congenital heart disease)
feature of chronic persistent viral infection
low level replication in regenrative tissue
example of chronic persistent viral infection
warts
feature of latent persistent viral infection
viral genomes maintained (e.g. neurones don’t divide so when nerve infected won’t be recognised by immune system) but no virus seen until immunocompromised
example of latent persistent viral infection
Herpes
what is the strategy of viral persistence
viruses contain many accessory genes allowing it to evade immune system, especially in skin and nervous system where immune activity is low
what is oncogenesis
viruses that cause cancer by encoding oncogenes
how does oncogenesis interfere with cell cycle
promote synthesis of virus and inhibit tumour suppressor genes
examples of oncogenesis viral infection
hep B and C, Epstein-Barr, HTLV-1 which causes leukaemia
define retrograde transport
virus transported from primary site of infection away from skin to CNS
define anterograde transport
virus transported to skin from neurones
outcomes of virus infection
balance of host response and viral virulence: sequence, load, co-morbidities, co-infections, other medications, host genetics, host age, host gender
viral sequence as outcome of infection
vary in virulence due to mutation
virus load as outcome of infection
dose of virus received
host immune response as outcome of infection
resistance
host co-morbidity as outcome of infection
other diseases present, pregnant, age, obesity
co-infections as outcome of infection
susceptible to other infections
other medications as outcome of infection
may affect immunity and susceptibility
host genetics, age and gender as outcome of infection
presence of particular mutated genes or different alleles may provide protection or increase susceptibility
