Retroviruses truly are dinosaurs, as Dr. Gillford and his colleagues demonstrated that there is an ancestor of human T-Cell lymphoma virus (HTLV) in the genomes of bats, and that this retrovirus has been around for 20-25 million years.
Why is this finding important, and why bats?
|image credit: University of Glasgow|
This significance of this finding is better understood by thinking about retroviruses. HTLV is a retrovirus that belongs to the genus Deltavirus. For many years people thought that it was impossible for retroviruses to infect humans, and it wasn’t until the early 1980’s that the first human retrovirus, HTLV, was discovered. Since 1911 it has been understood that viruses could cause cancer, but it was years before the connection between HTLV and adult T-cell leukemia/lymphoma (ATLL) could be convincingly made. It has been proposed that the initial introduction of HTLV into the human population came from simians, the same was HIV came into the human population, however, how the virus infected simians remained mysterious.
A lot of research recently has demonstrated that bats are often the reservoir for viruses, and then transmit them into many different mammalian species, which then can infect humans. For example: SARS, Ebola, and rabies were thought to have originated in bats . With Dr. Gillford’s work implicating bats in dinosaur retroviruses too, we can hopefully better understand how retroviruses came to infect humans.