Virus Pathogenesis Flashcards
(19 cards)
What are 3 virus pathogenic mechanisms?
- cell destruction following virus infection
- virus induced changes to cellular gene expression (cellular transformation by tumour viruses)
- immunopathogenic disease
What is an example of cell destruction following viral infection?
Death of T4+ cells by HIV
What are 2 examples of immunopathogenic disease?
-influenza A virus
Coxsackievirus- induced myocarditis
What are the site of viral entry? (7)
- conjunctiva
- arthropod
- capillary
- skin
- respiratory tract
- alimentary tract
- urogenital tract
What kind of virus does the influenza A virus cause?
respiratory infection
What kind of infections does enterovirus cause?
- enteric
- neurological
Describe the process of infection by the influenza A virus.
- virus infects cells of the respiratory tract
- destruction of respiratory epithelium
- altered cytokine expression leading to fever
Name 2 examples of cytokines that when expression is altered can lead to fever.
- interleukin-1
- interferon
What can cause a cytokine storm?
Avian influenza virus (H5N1)
What is antigenic drift?
gradual evolution of viruses to generate antigenic variants
What is antigenic shift??
significant changes in virus antigenic structure
What plays a key role in generating new virus types through antigenic shift?
non-human hosts
Name 5 examples of conditions and the enterovirus they are caused by.
- poliomyelitis (poliovirus)
- aseptic meningitis (many enteroviruses)
- myocarditis (coxsackie B viruses)
- pancreatitis (coxsackie B viurses)
- respiratory infection (many enteroviruses)
Give an example of a latent virus which has 2 types.
- Herpes simplex virus
- Type 1 =cold sores
- Type 2= genital lesions
Describe the process of infection by the latent herpes virus.
- primary infection of epithelial cells
- virus migrates to ganglia
- virus remains latent in nucleus= no virus replication
- stimuli such as sunlight reactivates virus
- virus migration to epithelial cells leading to virus replication
Give 2 examples of viruses which can induce tumours and what they can cause.
- Papillomaviruses- cervical carcinoma
- Retroviruses- lymphomas and leukaemias
What does HTLV-1 cause and how is it transmitted?
- variety of diseases including leukaemia (adult T cell lymphoma-leukaemia)
- transmission by blood and mother to child
What does HTLV-1 do?
modifies host cell gene expression using a transactivating protein (tax)
Describe the process in which retrovirus can induce tumours.
- virus infects cell
- virus nucleic acid, as DNA , integrates into cellular genome
- virus causes changes in cellular gene expression
- uncontrolled cell multiplication and tumour formation
