Virus Flashcards
What virus causes Chicken Pox?
Varicella Zoster Virus
What type of parasite is a virus?
Obligate Intracellular Parasite - must reproduce in cells - no ribosomes
Explain Virus structures
DNA/RNA (10s-100s of genes) - protein coat (capsid), surface proteins, sometime lipid envelope (avoids immune system)
What are 2 examples of viral testing?
Antigen testing - antibody derived from cells - recognise proteins(antigens) in biological samples
PCR - amplify specific nucleic acid sequence
What virus causes smallpox?
Variola major
How do virus infect cells?
Spike protein on virus binds to receptor proteins on host cell - inject nucleic acid into host cell - host replicated viral DNA - new virus assembled in cell e.g. capsid - sometimes & lipid envelope forms - host cells lyse & release virus
Example of viruses that spread via oral transmission
Hepatitis A, norovirus (2 bucket illness - emesis & diarrhoea), rotavirus (emesis), polio
Examples of viruses that spread via skin contact
HPV, Herpes Simplex Virus 1, Epstein Bar virus, Varicella-Zoster virus, Coxsackie
Examples of viruses that spread via sexual transmission
HIV, HPV, HSV-1
Examples of viruses that spread via droplet transmission?
SARS-CoV-2, rhinovirus (common cold), influenza, RSV, measles
Examples of viruses that spread via direct inoculation?
Hepatitis B, HIV, Yellow Fever virus, West Nile virus, Rabies
What is the average basic reproduction number?
Expected number of secondary infections caused by a single infected person - >1 = cases rise - <1 = cases fall
What is the case fatality rate?
Proportion of people who die from a specified disease among all positive cases over a period of time
Who is immune against monkeypox?
Anyone vaccinated against smallpox - Irish people born before 1972
What led to the eradication of small pox?
Vaccination - Jenner - inoculated with milder disease called cowpox - similar to small pox - led to immunity
Variolation - small sample from pustule placed in cut - small viral load - mild case of small pox - immunity