Prehistoric ancestor of leukaemia virus found in bats javascript:;

Ancient DNA traces from the family of viruses that cause a rare type of leukaemia have been found in the genomes of bats, filling the "last major gap" in retrovirus fossil record.‌‌‌ The research offers conclusive evidence that these viruses are between 20 and 45 million years old. The findings represent the first concrete piece of evidence that the 'Deltaretrovirus' group has a truly ancient origin in mammals. The results also offer key insights to the characteristics of these viruses and will allow scientists to better understand them in the future. The Deltaretrovirus group which includes T-lymphotrophic viruses, currently estimated to infect 15 to 20 million people worldwide, can cause a rare type of Non-Hodgkin Lymphoma called 'Adult T-Cell Leukaemia/Lymphoma (ATLL). Infection with this virus is very rare in the UK however, and most people who carry the virus will not develop the disease. It has long been thought that deltaretroviruses have infected humans since prehistoric times. However, because these viruses had no 'fossil record', their deeper origins have until now remained a mystery.