Macroscopic lesions of the ventriculus of Rhea americana , Linnaeus, 1758 (Aves: Rheidae) naturally infected by Sicarius uncinipenis (Molin, 1860) (Nematoda: Habronematidae).

There are few studies concerning the parasites of rheas. However, parasitism is the major cause of the limited success in captive breeding of these birds. Deletrocephalus dimidiatus, Deletrocephalus cesarpintoi, Paradeletrocephalus minor, and Sicarius uncinipenis are the most prevalent nematode species affecting these birds, but the lesions caused by these parasites have not been previously reported. Four adult rheas were necropsied to determine the presence or absence of gross lesions within the gastrointestinal tract, associated with parasitic infection. Two rheas parasitized by S. uncinipenis had ulcers on the koilin layer or had parasites penetrating this layer, resulting in widespread necrosis and hemorrhagic areas, whereas the 2 nonparasitized birds did not present lesions. The degree of injury was proportional to the parasitic load found in the birds. Thus, high parasitic loads can result in necrosis of the ventriculus, which may contribute to the death of birds, resulting in economic losses in the rural production of these birds.