Dispharynx nasuta (Nematoda: Acuariidae) in Guira guira and Crotophaga ani (Cuculiformes: Cuculidae) on Rio Grande do Sul State, Brazil

摘要

> face="Verdana, Arial, Helvetica, sans-serif" size="2">Nematodes of the genus Dispharynx (Railliet, Henry & Sisoff, 1912) are parasites of several groups of birds which have been primarily studied in birds of economic importance due to the injuries caused in the host proventricle. Dispharynx nasuta (Rudolphi, 1819) Stiles & Hassall, 1920, was found in two species of Cuculiformes, guira cuckoos, Guira guira Gmelin, 1788 and smooth-billed ani, Crotophaga ani Linnaeus, 1758, in the southern-most State of Brazil. From 2005 to 2008, 120 specimens of G. guira and 120 specimens of C. ani, were collected in Cacequi, São Vicente do Sul and Jaguari, Rio Grande do Sul State, Brazil. The prevalence of D. nasuta in G. guira was 28.3% and in C. ani 26.7%; the average intensity of infection was 8.81 (DP=18.41; Amplitude 1 - 82) helminths/host in G. guira and 5.10 (DP=6.17; Amplitude 1 - 30) in C. ani; the average abundance of infection was 2.28 (DP=10.02) helminths/host in G. guira, and 1.32 (DP=3.82) in C. ani, respectively. Comparative analysis between the species, sex, sexual maturity and seasonality showed that C. ani did not present significant differences with regard to any of the analyzed parameters. Guira guira presented some differences: females had more parasites than males (P=0.039); female birds collected in the winter (P=0.008) and male birds collected in the summer had more parasites (P=0.011); and immature males had more parasites than adult males (P=0.015). The injuries found in the proventricle of the parasitized birds were compatible with adenomatoid hyperplasia and with granulomatosis proventriculitis. This communication expands the number of host species and the geographic distribution of D. nasuta.