Tanapox virus was first isolated from the cases of febrile illness
that occurred along the Tana river in Kenya during 1950s. The virus produces
single, pock-like vesicular lesion on the skin, which usually do not progress
to form pustules. This lesion is most commonly seen on the upper part of the
body. The virus is acquired by insect bite from monkeys and other wild animal
reservoirs. It is antigenically not related to other poxviruses. The virus
grows in human and monkey tissue culture but does not grow in embryonated egg.
Yabapox virus produces large benign tumors in monkeys. It causes
benign histiocytomas 5–20 days after muscular or sub-cutaneous inoculation to
monkeys. Such lesions have been reported in persons handling affected monkeys.