Molecular Epidemiology of Avian Malaria in Wild Breeding Colonies of Humboldt and Magellanic Penguins in South America.

Avian malaria is a disease caused by species of the genera Haemoproteus, Leucocytozoon, and Plasmodium. It affects hundreds of bird species, causing varied clinical signs depending on the susceptibility of the host species. Although high mortality has been reported in captive penguins, limited epidemiological studies have been conducted in wild colonies, and isolated records of avian malaria have been reported mostly from individuals referred to rehabilitation centers. For this epidemiological study, we obtained blood samples from 501 adult Humboldt and 360 adult Magellanic penguins from 13 colonies throughout South America. To identify malaria parasitaemia, we amplified the mtDNA cytochrome b for all three parasite genera. Avian malaria was absent in most of the analyzed colonies, with exception of the Punta San Juan Humboldt penguin colony, in Peru, where we detected at least two new Haemoproteus lineages in three positive samples, resulting in a prevalence of 0.6% for the species. The low prevalence of avian malaria detected in wild penguins could be due to two possible causes: A low incidence, with high morbidity and mortality in wild penguins or alternatively, penguins sampled in the chronic stage of the disease (during which parasitaemia in peripheral blood samples is unlikely) would be detected as false negatives.