Microbiology - Viruses Flashcards
What are general features of viruses?
Nucleic acid
Protein coat
Protein spikes
Envelope
What are the stages of viral infiltration into a cell?
Attachment to receptor on cell membrane
Entry by pinocytosis/fusion of viral envelope and cell membrane
Uncoating which may be due to viral ion pump
**Nucleic acid and protein synthesis **using host ribosomes, may use viral enzymes
Assembly of virus crystals, may be visible under light microscope
Release by budding or lysis
What are possible targets of antiviral drugs?
Attachment
Entry
Uncoating
Viral nucleic acid polymerases
Viral enzymes - integrase, protease
Release
Immune adjuvants
What causes pathogenesis in a viral infection?
Cell death due:
lysis
hijacking of cell machinery
immune system - cytotoxic T cells
What types of cancer may be caused by human papilloma virus (HPV)
Cervical cancer
What type of cancer may be caused by Hepatitis B and C viruses?
Primary hepatocellular carcinoma
What cancer may be caused by Epstein Barr virus?
Lymphoma and Leukaemia
What virus causes Karposi’s sarcoma?
Human Herpes virus type B
Which immunoglobulins are involved in the defence against viruses?
IgM and IgG
What innate immune defences occur against double stranded RNA?
Induction of interferon
Ligand for Toll like receptor 3
What is latency?
Give two examples of viruses which lie latent and then reactivate.
When a virus is quiescent with no active replication.
Herpes simplex
Varicella zoster
Give two examples of viruses which may remain continually active for years
HIV
Hepatitis C
How can the presence of a virus be confirmed in the laboratory?
Antibody detection
Virus detection - PCR, antigen detection
Why are paired (acute and convalescent) blood samples often required?
To differentiate between new and past infection.
IgM vs IgG
