General global distribution of HIV infections.
General temporal trends in HIV infection rates.
The HIV pandemic (globally)
First described 1980~1981
South Africa: incredibly prevalent(普遍的)
Average age is low
Adults and children estimated to be living with HIV
South African people accounted for over 60%
Estimated number of children (<15 yrs) newly infected with HIV
Over 90% live in South Africa
The death number in decline due to advance in antiAIDS drugs (?)
Factors that explain why no cure or universal vaccine has been developed for
After 30+ yrs… still no cure or vaccine for HIV/AIDS. Why not?
1. HIV continues evolving, cures work for now may not necessarily work 10 yrs from now
2. Business issue
3. Challenge that how much our body own immune system can defend against HIV
4. HIV evolving and changing all the time, there’s no single one … that we can target on Reasons why viruses are not considered “alive”.
Viruses do not fit on the “Tree of life” (most)
They are not life because they cannot self-produce. They need host. (But some bacteria do this
They are not cell-base.
Obligate cellular parasites.
Anti-viral therapy often has serious side effects because the virus is using the host cell machinery
so we can’t really target it, can’t kill the virus, cause damages to the host cells and host tissues.
Reverse transcription, using RNA as a template, synthesizes DNA (most virus carry their genetic
information as DNA)
More proofreading enzymes associated with reverse transcription
Highly error-prone, results in mutation rate of HIV (over million times higher than the mutation
rate in human or other eukaryote)
Viral particle, much smaller than the host immune cell;
Virion (viral particle) enters host cell
Reverse transcriptase → viral DNA
Integrase(合成酶) splices(拼接) viral DNA into host DNA
Viral DNA transcription, RNA translation, viral protein
New vrions assemble(结合) and bud off, affect new immune cells, or lyse out(细胞溶解), and kill
the host cells/
Which of the steps in the virus life cycle are really specific to the virus? Philosophy behind
anti-retroviral therapies (ARTs)
Anti-retroviral therapies inhibit virus-specific enzymes