'1 in 6 with HIV lives in SA'
2008-04-18 09:00
Cape Town - The moment that HIV/Aids began spreading among the heterosexual population in 1987 it was like wildfire because at that stage it was not really a problem in South Africa and was scarcely found among sex workers.
Now, one in every six people on earth with HIV/Aids lives in South Africa.
These were the words of the executive director of the National Institute for Communicable Diseases, Professor Barry Schoub, at the 100th memorial meeting of the Royal Society of South Africa in Cape Town on Thursday.
About two thirds of people on earth with HIV/Aids live in sub-Saharan Africa (almost 22.5 million).
He said a vaccine was the only hope because scare tactics in education programmes were not really successful, especially in South Africa.
As with all other infectious diseases, HIV/Aids eventually would reach a plateau where there would be a balance between people who had the virus and those who didn't.
Chimpanzees are the example
If there were no intervention, the rate of infection would not simply keep rising.
If there was never any intervention against the spread of HIV/Aids, humanity possibly could eventually obtain a selective advantage over the virus and learn to live with it.
This idea could not be completely rejected seeing as chimpanzees, from whom humanity had got the virus, lived with it.
Chimpanzees that had the virus had tremendously high viral loads, but did not show any symptoms.
However, humanity could not wait for this to happen because this evolutionary adaptation could take thousand of years.
There were also people with a relevant mutation who were resistant to the disease. This occurred in 10% to 15% of Caucasians.
Antiretrovirals transformed the disease from a death sentence to a chronic illness, said Schoub.
The only way in which to exterminate the disease, as had been done with polio and smallpox, was to find a vaccine.
But, there already had been setbacks in the search.
The process was difficult because the researchers could not mimic that which they saw in other infectious diseases in an HIV/Aids vaccine because the virus was unique in many ways.
A person remained infectious for life and there was no way for the body to get rid of the virus.
Virus survives change easily
The virus mutated at a rate of 0.2 to 2 mutations per genome per replica cycle, which was extraordinarily fast.
The virus survived change easily and could handle big re-combinations and exclusions in the genome.
It relied on 200 human proteins in order to infect immunity cells.
The virus entered the nucleus, integrated itself in the chromosome and copied itself.