File picture: Pixabay

It was recently announced that researchers have found a way to cure mice of HIV infection, but the exact origin of the virus HIV-1 has been a matter of debate ever since its discovery. 

There is now a wealth of evidence on how, when and where HIV first began to cause illness in humans.

In 1999, researchers found a strain of Simian Immunodeficiency Virus (called SIVcpz) in a chimpanzee that was almost identical to HIV in humans.

The researchers concluded that it proved chimpanzees must have been the source of HIV-1, and that the virus had at some point crossed species from chimps to humans.

The same scientists then conducted more research into how SIV could have developed in the chimps. They discovered that the chimps had hunted and eaten two smaller species of monkeys. These smaller monkeys infected the chimps with two different strains of SIV.

The two different SIV strains then joined together to form a third virus (SIVcpz) that could be passed on to other chimps. This became the strain that could also infect humans.

But how did HIV make the jump from chimps to humans?

The most commonly accepted theory is that of the 'hunter'. In this scenario, SIVcpz was transferred to humans as a result of chimps being killed and eaten, or their blood getting into cuts or wounds of people during the course of hunting.

HIV is a type of lentivirus, which means it attacks the immune system. In a similar way, the SIV attacks the immune systems of monkeys and apes.

Since its first identification almost three decades ago, the pandemic form of HIV has infected at least 60 million people and caused more than 25 million deaths.

But as of last week there seems to be light at the end of this dark tunnel.

Researchers have successfully eliminated HIV from the DNA of an infected mice, a promising step towards a cure the million people living with the virus.

The researchers tested their methods on a group of infected “humanised mice,” or rodents engineered to produce human T cells similar to those found in humans susceptible, to HIV.

Combining CRISPR, a tool that can edit genes, with long-acting slow-effective release (LASER) antiretroviral therapy (ART) - a recently developed therapeutic strategy - the researchers were able to effectively eliminate replication-competent HIV DNA from the genomes of approximately 30% of infected humanised mice.

By the study’s end, researchers had successfully eliminated the virus from nine out of 23 mice. The results prove that HIV can be eliminated, researchers say.

Steven Deeks, a professor at the University of California at San Francisco who has worked extensively on HIV, said the use of gene editing to remove HIV from a live animal is a notable step forward.

But he cautioned that using the technique on humans would be far more challenging: Scientists will have to grapple with more variations in the virus, more difficulties in delivering the gene-editing technology and the possibility of cutting up human genes while trying to target HIV, he said. Those are formidable problems, Deeks said, especially with success depending on removing the virus completely.

While there is clearly a long way to go, it's a step in the right direction. 

Now, why is this important for Africa? Well, with under 20% of the world’s population, Africa is home to more than 60% of people living with HIV.

South Africa and Botswana have the highest infection rates in Africa, but countries in Africa have also been on the forefront of adopting interventions and treatments to tackle the pandemic.

* #NewsByte with Lance Witten is a product of the ANA+ digital channel. Find them on YouTube.