Yatapoxviruses

The genus Yatapoxvirus includes two members: yaba monkey tumor virus (YMTV), the type species, and tanapox virus (TPV). These viruses are primate specific and of African origin. YMTV infects monkeys naturally and humans only by accident or injection. TPV infects humans, and a strain of TPV, called yaba-like disease virus (YLDV), has been isolated from primates and their handlers in primate centers. The genomes of the known Yatapoxvirus members have all been sequenced and are among the smallest poxvirus genomes known: 134.7 kbp (YMTV) and 144.6 kbp (TPV/YLDV). YMTV and TPV share the genomic features of other poxviruses, including terminal inverted repeats at the ends of their linear double-stranded genomes and an A+T-rich (70-73%) sequence. YMTV infection of rhesus monkeys produces subcutaneous tumors that are composed of histiocytes, which actively divide and become spindle shaped. These large histiocytomas naturally regress over several months. TPV infection involves a short febrile illness followed by the appearance and development of individual, hard, raised nodules that regress after 3-4 weeks. Transmission of the yatapoxviruses is most likely via bite from an arthropod vector (mosquito), but their reservoir host species remains unknown.