Unit 5.2 - HIV

HIV

A disease that attacks and weakens the immune system.

HIV I – acute infection stage

HIV II – chronic stage

HIV III – AIDS stage

Progression depends on individual’s immune system, number of times exposed, and whether or not they are in treatment.

Pathophysiology

HIV affects white blood cells (any cell that has a CD4 receptor on it).

The cell with the most CD4 cells are the Helper T cells.

HIV connects to CD4 receptor cells then enters the cell.

Once it enters the cell it converts from a single stranded RNA cell to double stranded DNA cell.

HIV DNA enters the cell’s nucleus then creates copies of itself.

CD4 Count and Viral Load

The higher the CD4 count the better our immune system can function.

< 200 cells/mm3 = risk for opportunistic infections.

The higher the viral load, the greater the risk of HIV transmission.

< 40/mL = undectable

Transmission of HIV

Sexual Contact - unprotected anal or vaginal sex.

Blood Contact - sharing needles or injection equipment, blood transfusion prior to ‘85.

Vertical Transmission - during pregnancy, delivery, or breastfeeding.

HIV I

When an individual is exposed to HIV.

Our body will develop antibodies; this takes time, levels are undetectable but can still transmit to others (window period).

Symptoms resolve after body recovers and replenishes CD4 count; still highly infectious.

HIV II

Body has developed antibodies that starts to fight off HIV.

If untreated, eventually CD4 count drops, viral load rises.

If treated, individuals can remain at this stage for the rest of their life.

HIV III (AIDS)

CD4 count < 200 cells/mm3, viral load high.

AIDS = HIV diagnosis + opportunistic infection.