[Helminths of Pampas fox, Pseudalopex gymnocercus (Fischer, 1814) and of Crab-eating fox, Cerdocyon thous (Linnaeus, 1766) in the South of the State of Rio Grande do Sul, Brazil].

Forty wild canids were captured by live trap at Municipalities of Pedro Osorio and Pelotas in Southern of the State of Rio Grande do Sul and they were transported to the Parasitology Laboratory at the Universidade Federal de Pelotas. After they were posted, segments of intestinal, respiratory and urinary tracts and liver were separated and examined. Animal skulls were used for taxonomic identification. Of forty wild animals trapped, 22 (55%) were Pseudalopex gymnocercus and 22 (55%) Cerdocyon thous. The most prevalent nematodes were: Ancylostoma caninum (45.4 in P. gymnocercus and 22.2% in C. thous), Molineus felineus (9.9 in P. gymnocercus and 5.6% in C. thous), Strongyloides sp. (22.7 in P. gymnocercus and 16.7% in C. thous), Trichuris sp. (13.6 in P. gymnocercus and 11.1% in C. thous), and Capillaria hepatica (13.6 in P. gymnocercus and 5.5% in C. thous). The trematodes observed were: Alaria alata (36.4 in P. gymnocercus and 50.0% in C. thous), and Asthemia heterolecithodes in 5.6% C. thous. Cestodes were identified as Spirometra sp. (61.1% in C. thous and 54.5 in P. gymnocercus), Diphyllobothriidae, (81.8 in P. gymnocercus and 77.8% in C. thous) and an Acantocephala of the genus Centrorhynchus was also observed in 5.6% of C. thous only. These results indicated the helminths fauna in wild canids from the studied area.