Avipoxviruses (APVs) are large, complex DNA viruses that belong to the subfamily Chordopoxvirinae of the family Poxviridae [1]. APVs can naturally infect over 278 species in 23 orders of birds [2] and the effects of APV infection on wild bird species can be severe, which may even cause extinction of species. Undisputed examples come from the Hawaiian Islands, where extinctions of endemic forest birds are attributed to avian pox and avian malaria transmitted from introduced species [3]. The virus is transmitted via biting insects and aerosols and is usually named on the basis of bird s pecies from which the virus was rst isolated. The highly visible, wart-like lesions associated with the featherless areas of birds have facilitated recognition of avian pox since ancient times. The disease is characterized by proliferative lesions of the skin and diphtheric membranes of the respiratory tract, mouth, and esophagus of avian species [4]. APV infection in wild birds may produce several negative effects including elevated predation among affected birds [5], trauma, secondary infection, reduced male mating success [6], and death. Avian pox occurs worldwide, but little is known about its prevalence in wild bird populations. The increased frequency of reported cases of this highly visible disease and the involvement of new bird species during recent years suggest that avian pox is an emerging viral disease. Outbreaks are commonly reported at aviaries, rehabilitation centers, and other places where con-nement provides close contact among birds. The disease can

spread rapidly when avian pox is introduced into such facilities. Avian pox has rarely been reported in wild waterfowl.