(3) Antivirals Flashcards
How many people were living with HIV in 2012?
35.3 million
How many people were newly infected with HIV in 2012?
2.3 million
How many AIDS deaths were there in 2012?
1.6 million
Where is HIV most predominant?
Sub-Saharan Africa
Increasing epidemic in South and South-East Asia
What happens as HIV RNA copies rises?
CD4+ T cells decreases, immune system starts failing
What is an issue of antivirals?
Can get viral resistance if drug not taken consistently
What 2 classifications of infection do viruses cause and which is most common?
- acute
- chronic
Most viruses cause acute infections - body eradicates virus
Some viruses have RNA and some have DNA. In general, which causes acute and which causes chronic infection?
RNA = acute
DNA = chronic
but there are exceptions!
Give examples of acute viral infections
- influenza
- measles
- mumps
- hepatitis A
What are 2 further classifications of chronic viral infections?
- latent with (or without) recurrences
- persistent
Give examples of latent chronic viral infections
- herpes simplex
- cytomegalovirus
Give examples of persistent chronic viral infections
- HIV
- hepatitis B
- hepatitis C
What does herpes simplex cause?
Cold sores
Latent in 75% of people, activates in 10%
What type of genetic material does Hep C virus contain?
RNA (an exception to the rule!)
What is special about the genetic material of HIV?
RNA converted to DNA by reverse transcriptase
What do viruses consist of?
- nucleic acid (DNA or RNA)
- protein (coat - structural, enzymes - non-structural)
- +/- lipid envelope
Viruses are obligate intracellular parasites. What does this mean?
They can only replicate within cells, cannot reproduce outside their host cell
What 3 protein types does the HIV-1 genome code for?
- core structural proteins
- viral enzymes
- envelope structural proteins (extra-cellular and intra-cellular)
Give 3 viral enzymes coded for in the virus genome
- protease
- reverse transcriptase
- integrase
What are the stages in virus replication
- virus attachment to cell (via receptor)
- cell entry
- virus uncoating
- early proteins produced viral enzymes
- replication
- late transcription/translation - viral structural proteins
- virus assembly
- virus release
What is the purpose of virus uncoating?
Makes the genome available
What is a common target for molecular inhibition (anti-viral activity)?
Unique proteins encoded for by viruses, many of which are vital for virus replication and infectivity
Which enzyme do most antivirals target?
Polymerases
Which cells’ polymerases convert DNA to DNA
- eukaryotes
- DNA viruses
Which cells’ polymerases convert DNA to RNA
- eukaryotes
- DNA viruses