HIV is Getting Less Deadly
By Paul Rodgers
HIV is rapidly evolving into a less-dangerous bug and could one day become a disease that’s “almost harmless”.
Scientists have observed a surprising increase in the ability of some patients in Africa to live with the virus without getting Aids, the deadly syndrome in which their immune systems collapse.
“If the trend that we’ve seen in the last 10 years in Botswana were to continue – and I see no reason why it shouldn’t – the number of people who can control the virus through their immune system would definitely go up,” said Oxford University immunologist Phillip Goulder.
“It’s not impossible to see HIV becoming less of a cause of disease. And that’s what you see in the monkeys who are naturally infected with SIV [Simian Immunodeficiency virus], the relation of HIV, which is where we actually got HIV from. They suffer no disease at all,” he said.
“But it would be overstating it to say HIV has lost its potency. It’s still a virus you wouldn’t want to have.”
HIV mutates fast, allowing it to evade both the body’s natural defences and those thrown up by modern medicine, thus helping it to spread rapidly, infecting some 80 million people since it emerged in the 1980s, of whom half have died.
However, the central core, containing the viral RNA and crucial enzymes, is less able to evolve quickly.
Changes there in response to threats from the immune system or drugs damage its ability to replicate, according to Professor Goulder and his team, whose results are reported in Proceedings of the National Academy of Sciences.
“HIV adaptation to the most effective immune responses we can make against it comes at a significant cost to its ability to replicate,” Goulder said. “Anything we can do to increase the pressure on HIV in this way may allow scientists to reduce the destructive power of HIV over time.”
Professor Goulder’s team looked at 2,000 female patients in Botswana and South Africa. In Botswana, many of the patients have a gene variant called HLA-B*57 which helps to protect them. The HIV there has learnt to adapt to this, but in the process it has become less virulent.
This is not totally unexpected. Scientists have long believed that most viruses start out deadly, and mellow with age.
Killing the host quickly is a poor tactic for the bug. From the perspective of the virus, it’s better to have hosts live long enough to spread the invader to many others, much the way the common cold virus does.
However, working against this is pressure to reproduce quickly, so that there will be plenty of viral copies available to spread to the next victim during sex.
The scientists also found that treating the sickest patients accelerates mutation of the virus into varieties that reproduce more slowly.
“HIV adaptation to the most effective immune responses we can make against it comes at a significant cost to its ability to replicate,” Professor Goulder said. “Anything we can do to increase the pressure on HIV in this way may allow scientists to reduce the destructive power of HIV over time.”
Articles in this issue:
- Nurse Ethics Comes to a Head at Guantanamo Bay
- The Top 5 Nursing Issues for 2015
- Unprecedented Drug May Help Heal Damaged Spine
- HIV is Getting Less Deadly
- 20 Health Myths That Are Totally Wrong
- Why Kale, Acai and Agave Are Totally Overrated
- Health Concerns Are Causing Trouble in the Perfume industry
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