Study suggests weakening HIV virus
sensitive to drug treatments, contradicting a wealth of research
that demonstrates the emergence of drug resistant viral strains.
The news contrasts the widely-held belief that HIV would increase in virulence as it passed through more and more human hosts. Confirmation of this discovery could shape the direction and approach of current HIV drug research.
Scientists from the Institute of Tropical Medicine, in Antwerp, compared HIV-1 samples from 1986-89 and 2002-03. They found that the 2002-03 samples did not replicate as efficiently.
This would imply that over a number of generations, HIV could become less harmful to its human hosts.
However, they were only able to compare 12 samples from each time period, and they were unable fully to tease out any effect that drug therapy may have had on the virus.
Despite the promise of this study, there are questions as to whether it was possible to draw firm conclusions from such a small study.
Some strains of HIV have become naturally resistant to the presence of drugs such as antiretroviral therapy.
It has been estimated that up to 20 per cent of new infections now involve the transmission of resistant virus, meaning new classes of HIV drugs (especially against novel targets) will provide the only hope of treatment for an increasing number of patients.
The researchers, writing in the journal Aids, stressed the discovery did not mean efforts to prevent the spread of HIV should be scaled down.
"This was a very preliminary study, but we did find a pretty striking observation in that the viruses from the 2000s are much weaker than the viruses from the eighties," said researcher, Dr Eric Artz.
"Obviously this virus is still causing death, although it may be causing death at a slower rate of progression now. Maybe in another 50 to 60 years we might see this virus not causing death."
Exactly why the virus seems to be weakening over time is unclear although theories have been out forward.
"These findings suggest that HIV-1 replicative fitness may have decreased in the human population since the start of the pandemic," the study said.
"This 'attenuation' could be the consequence of serial bottlenecks during transmission and result in adaptation of HIV-1 to the human host."
If this were to be true, HIV could become less harmful to its human hosts.
"Obviously this virus is still causing death, although it may be causing death at a slower rate of progression now," Artz commented.
"Maybe in another 50 to 60 years we might see this virus not causing death."
According to the World Health Organisation, other diseases - such as smallpox, TB and syphilis - have shown similar behaviour, weakening over time.
Scientists have pointed to the phenomenon that demonstrates a natural trend to reach an equilibrium between the agent and the host interests, in order to guarantee concomitant survival for a longer time.
