Flashcards in Pathogens and host Deck (17)
what are some virus pathogenic mechanisms?
cell destruction following infection
virus induced changes to cellular gene expression
what are some sites of viral entry to the body?
respiratory, alimentary and urinogenital tract
what are some characteristics of acute viral infection?
localised to specific site of the body
development of viraemia with widespread infection of tissues
what is the pathogenesis of influenza A?
virus infects cells of the respiratory tract
destruction of respiratory epithelium
altered cytokine expression leading to fever
how are novel influenza viruses generated?
via antigenic drift and antigenic shift
what is antigenic drift with regard to influenza?
minor change in the genes of flu viruses, occurs naturally over time to generate antigenic variants
what is antigenic shift?
abrubt major changes in virus antigenic structure
what are some examples of enteroviruses?
how can viraemia occur with regard to enterovirus infection?
virus can spread to both neuronal and non neuronal tissues from the GUT.
what happens if neuronal tissues are affected with an enterovirus?
what is an example of a latent viral infection?
herpes simplex virus
what happens in a case of primary infection by the herpes simplex virus?
virus penetrates the epithelium, then migrates to the ganglia, where it remains latent in the nucleus
what happens in reactivation of the herpes simplex virus?
stimulus causes virus to migrate to the epithelium, where it is then released.
give examples of some virus - induced tumours.
cervical carcinoma- papillomaviruses
retroviruses - lymphomas and leukaemias
what is the replication cycle of a retrovirus?
attachment to target cell
viral rna infects the host cell's DNA using reverse transcriptase
viral DNA is synthesised and then integrated into the host cell's nucleus
what are some characteristics of human T lymphotrophic virus-1?
transmission by blood and mother to child
infects T cells
modifies host cell gene expression using a transactivating protein (tax)
variety of diseases including leukaemia
directly responsible for tumour