The Equine foamy virus ( EFV ), officially Equine foamy virus is a first described in 2000 virus , which is found in horses and to the family of retroviruses ( Retroviridae belongs). Within the retroviruses it is placed in the subfamily of the foamy or spumaviruses ( Spumaretrovirinae ), genus of the Equispumavirus . Compared to the other known foamy viruses, it is most similar to the bovine foamy virus (BFV), genus Bovispumavirus . On the other hand, it shows clear differences in the sequence sequence compared to the group of primate foamy virus (SFV), genus Simiispumavirus , which has been studied best .
As with other foamy viruses, there is no known disease associated with this virus. The distribution and frequency of EFV have not yet been investigated in more detail; 9 of 36 animals in the originally investigated horse population were positive.
The EFV genome comprises around 12,000 nucleotides and shows the typical foamyviral structure. However, a specialty is z. B. represents the motif in the active center of the protease . While this consists of the amino acids DSG or DSQ in other foamy viruses , EFV here has the sequence DTG. Furthermore, EFV differs from all other known foamy viruses in the absence of an ER signal in Env and the observation, which is probably related to this, that the budding of EFV does not take place on intracellular membranes, as in other foamy viruses, but on the plasma membrane.
