Macroscopic Lesions of the Ventriculus ofRhea americana, Linnaeus, 1758 (Aves: Rheidae) Naturally Infected bySicarius uncinipenis(Molin, 1860) (Nematoda: Habronematidae)

Abstract

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.

Natural infection by Procyrnea uncinipenis (Nematoda, Habronematidae), a parasite from rheas, an autoctone bird from South America, in emus Dromaius novaehollandiae, a ratite from New Zealand

“…Procyrnea uncinipenis is a nematode that infect the gizzard and proventriculum of rheas, Rhea americana , a native bird from South America. These nematodes have been reported in rheas from Brazil 4 , 8 – 11 and Argentina 12 . Another species, Procyrnea choique 13 , was described from another species of rhea, R. pennatta , from Argentina.…”

“…In rheas, there can be a high intensity infection, with more than 400 nematodes infecting the proventriculus and gizzard, causing widespread necrosis accompanied by a hemorrhagic appearance. The nematodes deeply penetrate the gizzard glands 4 . Although the emus had few specimens of P. uncinipenis in the gizzard (n = 4), infections with a high parasite load can occur and lead to the death of the birds.…”

“…This species is composed of five subspecies distributed in South America: R. americana americana (northeastern to southeastern Brazil), R. americana intermedia (southeastern Brazil and Uruguay), R. americana nobilis (eastern Paraguay), R. americana araneipes (western Paraguay, eastern Bolivia, and southwestern Brazil) and R. americana albescens (northeastern and eastern Argentina) 2 . These birds are found in open and stream areas 3 , and the presence of parasitic infections in these species is common, particularly those caused by the nematodes Procyrnea uncinipenis (Molin, 1860) and Deletrocephalus dimidiatus Diesing, 1851, Deletrocephalus cesarpintoi Vaz, 1936 and Paradeletrocephalus minor (Molin, 1861) 4 , 5 , both of which are considered host-specific.…”

“…The consequences of this parasite in other birds are unknown. In rheas, this parasitosis can lead to death4 . Procyrnea uncinipenis, as a Spirurid, has an arthropod as intermediate host, which is unknown.…”

A new species ofProcyrnea(Nematoda: Habronematidae) parasitic inRhea pennata(Aves: Rheidae) from Patagonia, Argentina, with a key to species of the genus

“…The identification and characterization of the nematode species affecting rheas is only possible by the examination of adult worms (Ederli & Oliveira, 2014). Most of the studies regarding the parasitic fauna of R. pennata are from specimens farmed in captivity (Chang Reissig et al , 2001); the information on wild populations is still scarce.…”