Fatal Paratanaisia bragai (Digenea: Eucotylidae) infection in scarlet macaws (Ara macao) in Costa Rica

We report on four fatal cases of renal infection due to Paratanaisia bragai in scarlet macaws (Ara macao) from two rescue centres in Costa Rica. At necropsy, birds had severe dehydration and cachexia. Two birds had hydropericardium, oedematous lungs, and liver lipidic degeneration. All birds had enlarged kidneys with brown pale discoloration and diffuse white spots on the cortical and sliced surfaces. Ureters were filled with many specimens of P. bragai. Histopathologically, the urinary system revealed multifocal interstitial lymphocytic-plasmacytic nephritis, multifocal mineralization of renal tubules, and interstitial fibrosis associated with flukes. Death of all scarlet macaws was related to severe nephritis leading to chronic renal failure due to P. bragai infection. It is plausible that P. bragai infection of scarlet macaws was accidental due to ingestion of the gastropod intermediate host inside the cages during the rainy season when humidity is higher and gastropods are more active. This represents the second report of parasitism by Eucotylidae digeneans in birds of Psittaciformes and the first in scarlet macaws.