One hundred seventy-two frogs (Leptodactylus chaquensis) were collected from November 2002 to November 2003, in agricultural (n = 132) and nonagricultural (n = 40) areas. Both sites are near the city of Corrientes, Argentina. The main goals of this study were as follows: (1) to determine the helminth parasite community in agricultural and nonagricultural habitats; (2) to analyze the relationships between helminth parasites and site of infection, frog body size, and gender; (3) to identify and examine covariation and association of helminth communities; and (4) to determine the mean richness and diversity of parasite communities. The helminth compound community of this amphibian species consisted of 24 species: 19 in agricultural habitats and 18 in nonagricultural habitats. The mean richness, mean diversity, and evenness of helminths were significantly different between the habitats (P < 0.05). The body size of the host was the important factor in determining parasite richness. Both habitats exhibited differences in community ordination. The helminth species in the 2 habitats exhibited the same interspecific relationships, although differences were observed in the intensity of infection.

A total of 36 adult individuals of Leptodactylus latinasus were collected near the city of Corrientes, Province of Corrientes in Argentina. The main goals of this study were: (1) to determine the helminth parasite fauna of L. latinasus; (2) to determine the richness and diversity of parasites at the component and infracommunity levels; (3) to analyze the relationships between helminth, frog body size and sex, and (4) to identify and examine species affinity of helminth communities. The helminth component community of this frog’s population consisted of 17 species. The predominant groups of parasites were the trematodes (adults: Glypthelmins repandum, Catadiscus inopinatus and Haematoloechus longiplexus; larvae: Travtrema aff. stenocotyle, Bursotrema aff. tetracotyloides, Styphlodora sp., unknown opisthogonimid species, Petasiger sp. and unknown strigeid species), followed by the nematodes (Cosmocerca podicipinus, C. parva, C. rara, C. cruzi, Schrankiana schranki and Aplectana hylambatis); other groups of parasites were represented by only one species (unknown larval cestode species and Centrorhynchus sp.). All parasite helminth species showed an aggregated pattern of distribution. The most infected organs were kidneys, small intestine, large intestine and pharyngeal zone. The host body size was important in determining the parasites abundance of G. repandum. At the level of component community G. repandum was the species with highest prevalence of infection and Bursotrema aff. tetracotyloides was the dominant species. Helminth species showed four significant pairs of covariation and two significant pairs of association in the infracommunities of Leptodactylus latinasus.

This article presents a survey of metacercariae found in tadpoles of 6 amphibian species collected near the city of Corrientes, Corrientes Province, Argentina. Larval digenetic trematodes of the following species were found: (1) Travtrema aff. stenocotyle Cohn, 1902 (Plagiorchiidae) from Physalaemus santafecinus, Physalaemus albonotatus, Odontophrynus americanus, Elachistocleis bicolor, Scinax nasicus, and Leptodactylus latinasus; (2) Styphlodora sp. (Plagiorchiidae) from O. americanus and E. bicolor; (3) Opisthogonimus sp. (Opisthogonimidae) from O. americanus and P. santafecinus; (4) Lophosicyadiplostomum aff. nephrocystis (Lutz, 1928) (Diplostomidae) from S. nasicus; (5) Bursotrema tetracotyloides Szidat, 1960 (Diplostomidae) from P. santafecinus and S. nasicus and (6) an unknown echinostomatid species from O. americanus and S. nasicus. Metacercariae of these species are reported for the first time in tadpoles of the 6 amphibian species examined. All species are described and illustrated, and their life cycles are briefly discussed. These larvae were found infecting different body parts of tadpoles, but no relationship was observed between the metacercariae and amphibian in a I format ions.

The main goals of this study were to compare the richness of parasitic trematodes in amphibians with diverse habits (terrestrial, fossorial, semi-aquatic and arboreal), and to evaluate whether the composition of the trematode community is determined by ecological relationships. Specimens were collected between April 2001 and December 2006 from a common area (30 ha) in Corrientes Province, Argentina. Trematodes of amphibians in this area comprised a total of 19 species, and were dominated by common species. Larval trematodes presented highest species richness, with the metacercaria ofBursotrema tetracotyloidesbeing dominant in the majority (7/9, 78%) of the parasite communities. Adults of the trematodeCatadiscus inopinatuswere dominant in the majority (6/9, 67%) of amphibians. The amphibiansLeptodactylus latinasus,Leptodactylus bufoniusandScinax nasicuspresented a high diversity of trematodes, whereasLeptodactylus chaquensishad the lowest diversity even though it presented with the highest species richness. The patterns of similarity among amphibian species showed groups linking with their habitats. Leptodactilid amphibians, with a generalist diet and an active foraging strategy showed highest infection rates with adult trematodes. The mean richness of trematode species related to host's habitat preferences was higher in semi-aquatic amphibians. Results suggest that semi-aquatic amphibians, present in both aquatic and terrestrial environments, present a greater diversity of parasites as they have a higher rate of exposure to a wider range of prey species and, hence, to diverse infective states. The trematode composition is related to the diets and mobility of the host, and habitat.