New study reveals REVs origins
REVs, which are the agents of virulent disease in poultry, were first found in 1950 and originated in mammals. The disease spread to birds after medical interventions.
"We became intrigued by these viruses because their distribution in nature suggests something very unusual has occurred during their evolution," Gifford said.
Evidence suggests that a viral genome integrated into a host genome during the hosts body. By examining fossilized snippets of viral DNA, the scientists were able to look at viral sequences that showed the REVs that are in birds today are linked to a viral infection that occurred in mammals over eight million years ago.
Looking at this genetic and historic data, the scientists concluded that REVs spread into birds very recently. They believe it was spread during the experimental studies of Plasmodium lophurae -- a malaria parasite that was isolated in the late 1930s from a pheasant housed in Bronx Zoo.
"Unfortunately, the law of unintended consequences applies in the realm of infectious disease research," Gifford said. "While we can't escape that fact, we can use modern sequencing technologies to survey viral genetic diversity, so that changes in the ecology and evolution of important viral pathogens can be monitored and responded to more effectively. Our analysis of REV illustrates how such an approach might work."