microBIO: The origin and diversity of HIV

HIV retrovirus (V I immunodeficiency H umana) is the causative agent of > AIDS I D efficiency A checked). Since it was discovered, there have been about 60 million people infected with HIV, of whom 25 million have died because of them. There are currently an estimated 33 million people living with HIV and about 2.1 million deaths a year.

The first cases of AIDS were first described in 1981. Why were no cases of this disease detected in advance ?, is it that AIDS did not exist before, where did the virus come from? Is it your origin? Are there more than one type of HIV virus or are they all the same? I will not now comment on those speculative, sensationalist, and science fiction theories about possible dark origins of the virus. I will summarize the data provided by comparative genetic analyzes between different viruses.

There are different types, groups and subtypes of HIV. The genetic variability of HIV is enormous due to the high rates of mutation and recombination, and its enormous replication capacity.

Sometimes even mixed infections occur that create new hybrid viruses, they are called forms recombinant forms (circulating recombinant forms, CRFs).

There is therefore no single type of HIV, there are several different, genetically different HIV and whose origin is also different. All come from SIV of primates, but from different primates and at different historical moments. Its geographical distribution is also different.

HIV-1 viruses from the M and N groups have originated directly, but independently, from SIV of chimpanzees (SIVcpz) in central and western Africa. Although the earliest evidence of HIV infection in humans is from 1959-1960, genetic analyzes suggest that group M is the oldest of HIV and is estimated to have appeared in the early decades of 1900. The emergence of the N group may be of the 60s. The viruses of groups O and P are related to the SIV of gorillas (SIVgor) of the Cameroon area. The origin of group O may be very similar to M, around the 1920's. The origin of HIV-2 appears to be in the SIV of a monkey type (SIVsmm) .

The SIVcpz chimpanzee virus (Pan troglodytes) comes from a recombination or mixture between a SIVcm of the gray or red-boned mangabeye monkey (Cercocebus torquatus) (Cercopithecus nictitans) .

A SIVgsn of the white-necked monkey (Cercopithecus nictitans) .

Knowing the origin and the enormous diversity of HIV is very important because it can have implications for diagnosis, virulence, transmission, vaccine development and treatments: for example, different types of HIV, will they respond equally to treatment ?.

Finally, monkeys are very cute, but very careful, they can host a universe of viruses to discover.

Hemelaar, J. (2012). The origin and diversity of the HIV-1 pandemic Trends in Molecular Medicine, 18 (3), 182-192 DOI: 10.1016 / j.molmed.2011.12.001

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