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