Viruses and Disease Flashcards
What are some features of viruses?
-Have DNA or RNA not both
-10s to 100s genes
-Protein coat (capsid)
-Obligate intracellular parasites
-No ribosomes
-Seen by elctron microscope
Simple virus life cycle
- Receptor binding
- Host replicates viral components
3.New viruses assemble - Release from host cell
How do viruses gain entry to hots cells?
By receptor binding
What kind of virus is Smallpox (dna or rna)
dsDNA - DOUBLE STRAND DNA
What kind of virus is Parvovirus?
ssDNA
What kind of virus is Rotavirus?
dsRNA
What kind of virus is coronaviruses?
+ssRNA
What kind of virus is measles?
-ssRNA
What kind of virus is HIV?
+ssRNA-RT - single stranded RNA retrovirus - uses reverse transcriptase (RT) to convert its RNA genome into DNA
What kind of virus is Hepatitis B?
dsDNA-RT
What is the difference between pos and neg ssRNA?
Pos RNA is similar to mRNA so can be immediately translated by host cell
Neg RNA is complimentary to mRNA and has to be converted to pos RNA by an RNA polymerase before translation
What are the diff groups of viruses?
- dsDNA e.g smallpox
- ssDNA e.g parvovirus
- dsRNA e.g rotaviruses
- +ssRNA e.g coronaviruses
- -ssRNA e.g measles
- +ssRNA-RT e.g HIV
- dsDNA-RT e.g Hep B
What does R0 of viruses mean?
Average Basic Reproduction Number
What is CFR of viruses?
Case Fatality Rate - bird flu v high
Note on Smallpox
-Eradicated Virus
-Originated in Africa
-Causes postules that cause lifelong scarring
-Variola major is more serious of the 2 kinds
-Variolation - used viral matter from smallpox patients - puss fom postule- and injected into healthy patient to create immunity
-DNA virus