The retroviruses which gave rise to HIV have been battling it out with mammal immune systems since mammals first evolved around 100 million years ago – about 85 million years earlier than previously thought, scientists now believe.
The remains of an ancient HIV-like virus have been discovered in the genome of the two-toed sloth [Choloepus hoffmanni] by a team led by Oxford University scientists who publish a report of their research in this week’s Science.
‘Finding the fossilised remains of such a virus in this sloth is an amazing stroke of luck,’ said Dr Aris Katzourakis from Oxford’s Department of Zoology and the Institute for Emergent Infections, James Martin 21st Century School. ‘Because this sloth is so geographically and genetically isolated its genome gives us a window into the ancient past of mammals, their immune systems, and the types of viruses they had to contend with.’
The researchers found evidence of ‘foamy viruses’, a particular kind of retrovirus that resembles the complex lentiviruses, such as HIV and simian retroviruses (SIVs) – as opposed to simple retroviruses that are found throughout the genomic fossil record.
‘In previous work we had found evidence for similar viruses in the genomes of rabbits and lemurs but this new research suggests that the ancestors of complex retroviruses, such as HIV, may have been with us from the very beginnings of mammal evolution,’ said Dr Aris Katzourakis.
Some ideas about the origin of AIDS are opposed to the scientific consensus. This study is iteresting:
We examined beliefs about the origin of HIV as a genocidal conspiracy in men and women of four racial/ethnic groups in a street intercept sample in Houston, Texas. Groups sampled were African American, Latino, non-Hispanic white, and Asian. Highest levels of conspiracy theories were found in women, and in African American and Latino populations (over a quarter of African Americans and over a fifth of Latinos) with slightly lower rates in whites (a fifth) and Asians less than one in ten). Reductions in condom use associated with such beliefs were however only apparent in African American men. Conspiracy beliefs were an independent predictor of reported condom use along with race/ethnicity, gender, education, and age group. Data suggest that genocidal conspiracy beliefs are relatively widespread in several racial/ethnic groups and that an understanding of the sources of these beliefs is important to determine their possible impact on HIV prevention and treatment behaviors.