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Viral taxonomic tree
Where does HIV fit in?
HIV
A few other old friends, just for context
flu
coughs, colds
EbolaHIVSARS
HepA
HepB
HepC, dengue, West Nile
coughs, colds
measles, mumps
HPV
rabies
rubella
mono, shingles,chickenpox
smallpox
A closer look at HIV
http://visualscience.ru/en/illustrations/modelling/hiv/
An even closer look
Where did HIV come from – and how do you figure that?
sequence similarity in gag, pol and env regions
When?
HIV-1:
biologically verifiable:•1959, adult male DR Congo•1960, adult female DR Congo•1969, US teen •1976, Norwegian sailor
estimates from sequence comparisons and computer modeling:•1940s-1950s•1931 ± 15 years•1884-1924 (based on differences between 1959 and 1960 samples)
HIV-2:
less studied; 1945 ± 16 years
http://www.avert.org/origin-aids-hiv.htm
How?
1.bushmeat trade*
2. re-use of needles and other medical equipment without adequate sterilization
2b. "Heart of Darkness"
3. international travel
4. blood transfusions and isolated clotting factor
5. substance abuse
* no, you perverts, not interspecies sex
Africa
everywhere
From African epidemic...
http://www.avert.org/history-aids-africa.htm
... to global pandemic
10.1073/pnas.0705329104
UNAIDS 2008 report
UNAIDS 2008 report
1981: First AIDS case reported1984: Human immunodeficiency Virus (HIV) identified 1985: First test for HIV licensed (ELISA)1987: First Western Blot blood test kit1992: First rapid test 1994: First oral fluid test1996: First home and urine tests2002: First rapid test using finger stick2003: Rapid finger stick test granted CLIA waiver 2004: First rapid oral fluid test (also granted CLIA waiver)2006: CDC releases new U.S. guidelines recommending routine HIV screening of all adults in health care settings
Key dates in the history of HIV testing:
http://aids.about.com/od/newlydiagnosed/a/hivtimeline.htm
http://www.kff.org/hivaids/upload/6094-05.pdf
I work for this company!(insert disclaimer here)
How do you test for HIV?
1. detect the virus directly detect viral proteins (mostly p24, capsid) detect viral nucleic acid (PCR, LAMP)
2. detect the host immune response to the virus: antibodies ELISA western blot rapid testing/lateral flow
days
level
How do you test for HIV?
ELISA
western blot
Rapid testing – mostly lateral flow immunochromatography
• fast – 20 min – reduces loss to followup!• easy to use, no instrumentation• cheap (ish) – $7-12• portable• screening not diagnosis
Basic anatomy of a lateral flow strip
Wong &Tse, Lateral Flow Immunoassay
http://microgravity.hq.nasa.gov/general_info/homeplanet_lite.html
How it works