Occurrence of Paratanaisia spp. Freitas, 1951 in a domiciled cockatiel (Nymphicus hollandicus, Psittaciformes: Cacatuidae).

Digenetic eucotylids of the Paratanaisia genus are widely reported parasites of the avian renal system. The infection, commonly reported in free-living and zoo-housed birds, is described for the first time in a domiciled bird, a cockatiel kept as pet bird with free access to the yard outdoors. The bird was received at Veterinary Hospital, where clinical and radiographic evaluations suggested a case of heavy-metal poisoning. Although the bird received supportive care and a chelating agent, it died the next day. The necropsy showed friable kidneys and congestion of blood vessels in structures such as the skin, proventriculus, brain, and skullcap. The histopathological evaluation of the kidneys revealed multifocal hemorrhages, commonly found in cases of heavy-metal poisoning. Parasitic structures similar to those of the digenean trematodes Paratanaisia spp. were also observed inside dilated collecting ducts, which presented epithelial cell flattening and vacuolization. There was compression of adjacent tissue and discrete fibrotic areas. In the presence of intermediate hosts in the yard, the synanthropic nature of some wild free-living birds could make them a source of trematodes infection and dissemination for pet birds. Conversely, the infected cockatiel could also have served as a reservoir and carrier of trematodes to wild free-living birds.