AIDS virus weakening
the human immunodeficiency virus (hiv) that causes aids is attenuating (getting weaker), claim scientists at the Institute of Tropical Medicine in Antwerp, Belgium. They say their study suggests if the attenuation observed in hiv-1 continues, aids may not remain life-threatening 50-100 years from now.
Attenuation is a survival tactic used by viruses that have fast rates of killing. If their virulence does not lessen, such viruses may be left with fewer or no hosts to live off. The attenuation observed in hiv is similar to that found in the simian immunodeficiency virus (commonly called siv), which is never fatal to its host, the chimpanzee.
"The mechanisms responsible for possible hiv-1 attenuation are complex but likely to involve directional evolution towards increased survival and transmission at the cost of lowering virulence,' says lead author Kevin K Arien. The findings appear in aids (Vol 19, No 15, October 14, 2005), the journal of the International aids Society.
The study compared hiv-1 samples from 1986-1989 to that of strains from 2002-2003. Twelve samples from each period were tested on two counts