Inadvertent transfer of a mammalian retrovirus into birds

Reticuloendotheliosis viruses (REVs) are retroviruses that cause a rare disease of gamebirds and waterfowl that includes anemia, immunosuppression, neoplasia, runting, and abnormal feathering. Since the first isolation of REV from a turkey in 1957, REVs were believed to be strictly avian viruses. It now appears that REVs are mammalian viruses that were accidentally introduced into birds in the 1930s during research on malaria. During an investigation of endogenous retrovirus diversity in Malagasy mammals, the authors found sequences related to REVs in the genomes of the ring-tailed mongoose and the narrow-striped mongoose. Phylogenetic analyses revealed that REVs entered the germline of these mammals ~8 million years ago. The entire REV lineage of mammalian and avian viruses  originated from a common founder that circulated among mammals from 23 to 25 million years ago. Based on their finding that REVs originated in mammals, the authors attempted to determine when the viruses made the jump into birds. They determined the genome sequence of an REV isolated from a duck, called duck infectious anemia virus (DIAV), and constructed phylogenies with other available REV sequences. Duck infectious anemia virus, and the closely related REV spleen necrosis virus (SNV), were both isolated from ducks that were infected with Plasmodium lophurae in 1959. Apparently the P. lophurae stocks used were contaminated with these viruses. A search for a strain of malaria that could be used to stud...
Source: virology blog - Category: Virology Authors: Tags: Basic virology Information bird fowlpox virus gallid herpesvirus iatrogenic reticuloendotheliosis virus viral Source Type: blogs