It may take several years for a HIV-positive person to develop Aids. People with Aids survive for one to three years on average, but there are people that have had Aids (not HIV) for more than five years.
HIV-positive people are normal people, who pose no threat to anyone as long as you don't make love to them without a condom.
HIV can also be spread from mother to child via the placenta (vertical transmission) and breast milk, and by receiving infected blood through blood transfusions, shared needles, etc.
What do you need to know?
The body recognises the virus and tries to kill it by producing antibodies within three to six months after the infection. This is the time where the ELISA (enzyme-linked immunosorbent assay) and Western blot tests are negative and is called the window period.
During this time the PCR (polymerase chain reaction) test will be able to tell if you have been infected by detecting viral nucleic acid. The ELISA and Western blot tests are 99.9% accurate.
If you have a HIV-positive blood test, it means that you have antibodies against the HI virus. There are people who test negative for HIV antibodies, but are PCR positive for years. However, this is very rare and these people are 400 times less infective than other HIV-positive people.
The Aids virus infects, replicates in and destroys cells like B-lymphocytes, macrophages, microglial cells of the brain and dendritic cells in the skin, but it mainly targets CD4 lymphocytes.
CD4 lymphocytes direct the other cells in the immune network when an immune reaction takes place and are also known as CD4 helper-inducer lymphocytes.
It stands to reason then that if the CD4 lymphocytes don't work properly, the whole immune mechanism suffers. This is also why the CD4 count is a good marker of how far the disease has progressed.
Some of the Aids treatments target this enzyme to stop replication of the virus and in that way slow down the progression of the disease.
Life cycle
Have a look at a simplified version of the life cycle of the HI virus:
1. The GP120 spikes attach to the receptor proteins on the wall of the CD4 cell.
2. The virus penetrates the CD4 cell and sheds its protein coat.
3. The virus releases its genetic material (RNA) along with the reverse transcriptase enzyme.
4. The reverse transcriptase enzyme uses the single-strand RNA as a template to form a double strand DNA copy.
5. This new viral DNA now enters the cell nucleus and joins with the cell's own DNA.
6. It now hijacks and reprograms the DNA to produce more viral RNA.
7. The cell can no longer carry out its normal functions, but instead has become a virus factory with its hijacked DNA sending out many strands of new viral RNA to construct new HIVs.
8. The new HIVs erupt from the cell and often cause cell death.
9. These new HIVs now infect many more CD4 cells and lead to the crippling of the patient's immune cells.
10. This eventually leads to Aids.