Avian Pox in Magellanic Penguins (Spheniscus magellanicus)

Avian pox is an enveloped double- stranded DNA virus that is mechanically transmitted via arthropod vectors or mucosal membrane contact with infectious particles or birds. Magellanic Penguins (Spheniscus magel- lanicus) from two colonies (Punta Tombo and Cabo Dos Baho´as) in Argentina showed spo- radic, nonepidemic signs of avian pox during five and two of 29 breeding seasons (1982- 2010), respectively. In Magellanic Penguins, avian pox expresses externally as wart-like le- sions around the beak, flippers, cloaca, feet, and eyes. Fleas (Parapsyllus longicornis) are the most likely arthropod vectors at these colonies. Three chicks with cutaneous pox-like lesions were positive for Avipoxvirus and revealed phylogenetic proximity with an Avipoxvirus found in Black-browed Albatross (Thalassarche melanophrys) from the Falkland Islands in 1987. This proximity suggests a long-term cir- culation of seabird Avipoxviruses in the south- west Atlantic. Avian pox outbreaks in these colonies primarily affected chicks, often result- ed in death, and were not associated with handling, rainfall, or temperature.