Cowpox is due to infection by an orthopoxvirus. Human disease is caused by cutaneous inoculation from an infected host. Cowpox is endemic in Europe amongst small rodents, particularly wood mice and wood voles. After a seven day incubation it causes a systemic febrile flu-like illness. Lesions are solitary or few, mainly affecting the face and
hands. An initial erythematous papula or blister later forms a crusted eschar which heals slowly leaving a deep pock-like scar.