AIDS could become a thing of the past as the virus that causes the fatal disease is becoming less contagious and deadly, according to a new study.
Scientists at Oxford University said their study of HIV in more than 2,000 women in Africa showed it was slowing in its ability to cause AIDS and this could contribute to an end to the deadly pandemic that has killed around 40 million people since it first broke out more than 30 years ago.
Around 35 million people are estimated to have HIV or AIDS globally. Experts said the trend in HIB becoming less virile could mean it eventually becomes "almost harmless".
"Overall we are bringing down the ability of HIV to cause AIDS so quickly," Philip Goulder, a professor who led the study, told Reuters.
HIV could evolve to become 'almost harmless'
"But it would be overstating it to say HIV has lost its potency -- it's still a virus you wouldn't want to have."
For the first time, the annual number of new HIV infections a year is lower than the number of HIV positive people being added to those receiving treatment, which experts say is a major step forward in reducing deaths from AIDS.
"That’s a really big deal," campaign group One said. "It means we’re finally getting ahead of this disease."
Prof Goulder's team conducted their study in Botswana and South Africa and found HIV goes through a process of weakening when it infects someone with a more robust immune system.
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HIV thrives off its ability to replicate itself and mutate to overcome patients' immune systems.
Prof Goulder said HIV going through a process of weakening was a major step towards eliminating AIDS altogether.
"It is quite striking. You can see the ability to replicate is 10% lower in Botswana than South Africa and that's quite exciting," Prof Goulder told the BBC.
"We are observing evolution happening in front of us and it is surprising how quickly the process is happening.
"The virus is slowing down in its ability to cause disease and that will help contribute to elimination."
His team found that HIV takes 10% longer to develop into AIDS in Botswana than South Africa. The former has had an HIV problem for longer and so the less virile strain of the disease had developed.
Prof Goulder's team's results were published in the journal Proceedings of the National Academy of Sciences (PNAS).
The study also suggested the use of certain drugs forced HIV to evolve into less virile forms.
The news comes after people across the globe marked World AIDS Day, which saw public figures back the fight to end the pandemic that has killed millions.