High Quality Content by WIKIPEDIA articles! Adeno-associated virus (AAV) is a small virus which infects humans and some other primate species. AAV is not currently known to cause disease and consequently the virus causes a very mild immune response. Gene therapy vectors using AAV can infect only dividing cells and persist in an extrachromosomal state without integrating into the genome of the host cell. These features make AAV a very attractive candidate for creating viral vectors for gene therapy, and for the creation of isogenic human disease models. Recent human clinical trials using AAV for gene therapy in the retina have shown promise.