Cercariae (Digenea: Strigeidae, Diplostomidae) in Biomphalaria straminea (Planorbidae) from a rice field in Northeastern Argentina

The rice fields can provide habitats for many species of aquatic invertebrates, as insects, molluscs, crustaceans; and vertebrates, as fish, amphibians, reptiles and birds, which may act as hosts in the life cycles of digenean parasites. In this context, the goal of the present study was to describe the cercariae found in Biomphalaria straminea from a rice field in Northeastern Argentina. This freshwater snail inhabits a wide variety of environments, favoring shallow, temporary and standing or slow-flowing freshwater bodies. For this study, snails were collected from the cultivated parcels and irrigated channels during the flooding periods (from the time of sowing to soon after harvesting of the rice) between December 2010 and May 2011 and December 2011 and April 2012, in a rice field from Corrientes province, one of the main rice producers of Argentina. A total of 5 510 snails were examined of which 26 were infected with three different larval trematodes belonging to Strigeidae, Furcocercaria V (0.40 %) and Furcocercaria XX (0.04 %), and Diplostomidae, Furcocercaria XIX (0.04 %). Furcocercaria XX and Furcocercaria XIX were present in one rice cultivation cycle, while Furcocercaria V was present in both rice cultivation cycles. The prevalence of the different furcocercariae was somewhat higher in the second rice cultivation cycle. The cercariae described are new records for Argentina that added to 53 cercariae previously reported for Biomphalaria spp. in different aquatic environments of country. The study of the digenean larval in rice fields is important because contribute to the knowledge of the biodiversity of these environments.Fil: Fernández, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Larvas de nematoides encontradas em anfíbios no nordeste da Argentin

Five species of amphibians, Leptodactylus podicipinus, Scinax acuminatus, S. nasicus, Rhinella fernandezae and Pseudis paradoxa, were collected in Corrientes province, Argentina and searched for larval nematodes. All larval nematodes were found as cysts in the serous of the stomach of hosts. Were identified one superfamily, Seuratoidea; one genus, Spiroxys (Superfamily Gnathostomatoidea) and one family, Rhabdochonidae (Superfamily Thelazioidea). We present a description and illustrations of these taxa. These nematodes have an indirect life cycle and amphibians are infected by consuming invertebrate, the intermediate hosts. The genus Spiroxys and superfamily Seuratoidea were reported for the first time for Argentinean amphibians.Cinco espécies de anfíbios, Leptodactylus podicipinus, Scinax acuminatus, S. nasicus, Rhinella fernandezae e Pseudis paradoxa, foram coletadas na província de Corrientes, Argentina e pesquisadas para achar nematoides larvais. Todas as larvas foram encontradas como cisto na serosa do estômago dos hospedeiros. Foram identificadas uma superfamília, Seuratoidea, um gênero, Spiroxys (Superfamília Gnathostomatoidea) e uma família, Rhabdochonidae (Superfamília Thelazioidea). Apresentamos uma descrição e ilustrações dos táxons. Estes nematoides têm um ciclo de vida indireto e os anfíbios são infectados pelo consumo dos invertebrados, os hospedeiros intermediários. O gênero Spiroxys e a superfamília Seuratoidea são relatados pela primeira vez para anfíbios da Argentina.Fil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Cosmocercid Nematodes of Three Species of Frogs (Anura: Hylidae) from Corrientes, Argentina

We collected 142 hylid frogs representing 3 species, chaco treefrog Hypsiboas raniceps, dwarf treefrog Dendropsophus nanus, and sanborn treefrog Dendropsophus sanborni, near the city of Corrientes, Corrientes Province, Argentina, between January 2002 and December 2003, and we examined them for nematodes. Two species of cosmocercid nematodes were found infecting the large intestine of these hosts. Cosmocerca parva was found infecting H. raniceps and D. sanborni, whereas Cosmocerca podicipinus was found infecting D. nanus. These nematode species are reported for the first time from these hylids from Corrientes, Argentina. KEY WORDS: Hylidae, Hypsiboas raniceps, Dendropsophus nanus, Dendropsophus sanborni, Nematoda, Cosmocerca parva, Cosmocerca podicipinus, Corrientes, Argentina.Fil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Nematodes of Amphibians from the South American Chaco: Distribution, Host Specificity and Ecological Aspects

This is the first review of the nematode parasites of amphibians from Dry Chaco (DC) and Humid Chaco (HC) ecoregions of South America, covering aspects related to their systematics, distribution, host range and ecology, including their life cycles. Of approximately 100 species of amphibians that inhabit these ecoregions, the nematode parasites of 32 species are known. The parasite species consisted of 51 taxa: 27 in HC and 18 in DC. The family Cosmocercidae alone included 18 species. Aplectana hylambatis and Cosmocerca podicipinus showed the widest geographical and host distribution. Leptodactylus bufonius and Rhinella major presented a high number of nematode parasites. The species richness of nematodes was related to the host body sizes and to the strategy to obtain prey. The mean species richness was higher in terrestrial amphibians with intermediate characteristics in the generalist–specialist spectrum in terms of diet, and in amphibians with intermediate characteristics between actively foraging and the “sit-and-wait” approach in terms of searching for prey. The patterns of similarity among amphibian species showed groups linking with their habitats. Nematodes usually have direct life cycles with the infectious form entering the host passively or actively. However, many amphibians are also involved in heteroxenous cycles that develop in the aquatic environment.Fil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Duré Pitteri, Marta Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Parasite and reproductive features of Scinax nasicus (Anura: Hylidae) from a South American subtropical area

Desde febrero de 2002 a diciembre de 2004, se analizó la fauna de helmintos parásitos y las características reproductivas de Scinax nasicus en un área cercana a la ciudad de Corrientes, Argentina. La fauna de parásitos helmintos estuvo conformada por 15 especies de helmintos (larvas y adultos) incluyendo trematodes (73%), nematodes (20%) y acantocéfalos (7%). La especie Opisthogonimus sp. presentó la mayor prevalencia (41%) de infección. Los hospedadores definitivos de esta metacercaria son probablemente las serpientes. Scinax nasicus, interviene como segundo hospedador intermediario, infectándose por la penetración directa de cercarias. El número de óvulos maduros por hembra (complemento ovárico) osciló entre 413-3922, mientras que el diámetro medio de los óvulos fue de 0,76 ±0,17mm. Esta especie posee un patrón reproductivo prolongado.From February 2002 to December 2004, the helminth parasite fauna and reproductive features of the frog Scinax nasicus were studied from Corrientes city, Province of Corrientes, Argentina. The parasite richness was 15 species of helminths (larval and adult) including trematodes (73%), nematodes (20%) and acanthocephalans (7%). Opisthogonimus sp. showed the highest prevalence (41%). The definitive hosts of these larval trematodes are probably snakes; S. nasicus acts as second intermediate host, and become infected by direct penetration of cercariae. The number of mature ova per female ranged from 413 to 3922, and the mean mature ovum diameter was 0.76 ±0.17mm. This species has a prolonged reproductive pattern.Fil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Duré Pitteri, Marta Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Schaefer, Eduardo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Morphological variation of aplectana hylambatis (Nematoda: Cosmocercidae) from different anuran hosts and localities in Argentina

Aplectana hylambatis is a nematode witha wide geographic distribution and low host specificity. In spite of numerousreports, until this moment, the morphological variations between differenthosts and localities have not been studied. We studied 401 specimens collectedfrom five host species from seven localities in Argentina, and examined thefollowing morphological characters: mamelon-like cuticular protuberancesanterior to the vulva, structure of the gubernaculum and the spicules, numberand arrangement of caudal papillae, and the measurements of twelve charactersin females and eleven characters in males. The results showed that mamelon-likeprotuberances and caudal papillae varied in number and arrangement between differenthosts and localities. The metrical study revealed that five characters in malesand six in females contributed to variability; nine characters showedsignificant differences between host species and localities. Specimens of A.hylambatis collected from R. arenarum formed a group clearly differentiatedfrom the rest of the specimens. The results from this study highlight theimportance of examining as many specimens as possible from different hostsamples and from several localities to cover the intraspecific variations.Fil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gómez, Valeria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Metacercariae of Strigeidae Parasitizing Amphibians of the Chaco Region in Argentina

The goal of the present study was to analyze the metacercariae found in adultamphibians collected in the Argentinean Chaco region. A total of 194 frogs,Leptodactylus chaquensis, Leptodactylus latinasus, and Lepidobatrachus laevis wasexamined for digeneans. Three different larval trematodes of the genus Strigea(Digenea, Strigeidae) were found infecting the liver, mesentery, body cavity, andmuscle of frogs. These metacercariae are described and illustrated for the first time andprovide new information on the composition of metacercariae in amphibians, thuscontributing to the knowledge of larval trematodes biodiversity in the Neotropicalregion. We also present new information on the morphology and morphometry of strigeid metacercariae.Fil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Fernández, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Community Structure of Helminth Parasites of Leptodactylus bufonius (Anura: Leptodactylidae) from Northeastern Argentina

The main goals of this study were to determine the richness and diversity of helminth parasites of Leptodactylus bufonius at the component and infracommunity levels and evaluate whether the composition of the parasite community is determined by biotic and abiotic factors. In total, 76 specimens were collected near the city of Corrientes, Corrientes Province, Argentina. The helminth component community in L. bufonius in this area was comprised of 16 species. The predominant groups of helminth parasites (larval and adult) were trematodes (50%) followed by nematodes (38%); other groups of parasites were represented by only 1 species (Cestoda: Cylindrotaenia sp. and Acanthocephala: Centrorhynchus sp.). Helminth species showed unequal abundances with a typical aggregated pattern of distribution. The prevalence of infection was 93% in specimens of L. bufonius examined. The main helminth species in the community was Aplectana hylambatis (importance value: I = 96.41), followed by Catadiscus inopinatus (I = 2.32). At the infracommunity level, the mean individual species richness was no more than 3 helminth species per infected host; the diversity and equitability of helminths were 0.18 ± 0.14 and 0.44 ± 0.32, respectively. The host body size was the main factor in determining the infrapopulation structure of various helminth species. Species richness was significantly and positively correlated with the host body size. Data revealed significant positive correlations between helminth species (Cat. inopinatus/Centrorhynchus sp. and A. hylambatis/Centrorhynchus sp.). A significant negative correlation was observed between A. hylambatis and C. podicipinus. Only 2 associations were found among the 7 species considered. The parasite community of L. bufonius showed wide variations in its helminth fauna and included helminths of aquatic and terrestrial habitats. The correspondence between host habits and parasite biology is reflected in the parasites harbored by these amphibian hosts.Fil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Kehr, Arturo Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Larval trematodes of Biomphalaria straminea (Mollusca: Planorbidae) in a ricefield in Corrientes Province, Argentina

AbstractA total of 3 494 snails from Biomphalaria straminea (Dunker, 1848) were collected from December 2010 to May 2011, in a ricefield in Corrientes province, Argentina, and 5 species of larval trematodes belonging to Strigeidae (Furcocercaria sp. XIV, Furcocercaria sp. XV, Furcocercaria sp. XVI), Diplostomidae (Furcocercaria sp. XVII) and Schistosomatidae (Furcocercaria sp. XVIII) found in 115 snails (3.29%) are described. Prevalence of infection ranged between 0.11% (e.g., Furcocercaria sp. XVIII) and 4.22% (e.g., Furcocercaria sp. XVI) in the snails examined. Furcocercaria sp. XIV, Furcocercaria sp. XV and Furcocercaria sp. XVI were the most common species present in nearly all months of the sampling period, whereas Furcocercaria sp. XVII and Furcocercaria sp. XVIII were rarer species. Infection rates of most larval digeneans were highest in March. The species of furcocercariae in B. straminea from the agricultural habitat described in the present study are now added to the 4 species of furcocercariae already reported for the region from the genus Biomphalaria

First record of the genus choledocystus (Trematoda: Plagiorchiidae) for amphibians of the chacoan region in argentina

This is the first record of the trematode Choledocystus incurvatum and Choledocystus elegans in Argentinean amphibians collected in two localities of the Chacoan region. The first trematode species was found infecting the small intestine of Pseudis paradoxa Linnaeus, captured near the city of Corrientes, Corrientes Province; the second species was found infecting the gall-bladder of Lepidobatrachus laevis Budgget, captured in Ingeniero Juárez, Formosa Province. Morphology of these species was studied in detail using light microscopy and scanning electron microscopy (SEM), and compared with previous studies of Brazilian and Venezuelan specimens. Morphological descriptions of these parasites are provided to supplement existing data. Choledocystus incurvatum was characterized using molecular methods by sequencing and analyzing rDNA. Regarding metric characters of C. incurvatum, the Argentinean specimens show some differences in body and egg size (some larger than Venezuelan specimens). For C. elegans the specimen shows smaller body size than Brazilian specimens. SEM observations of C. incurvatum showed tegument covered with triangular spines and confirmed presence of a sucker-like structure around the genital atrium. The morphological and genetic data on C. incurvatum contribute to a more thorough diagnosis of the genus. Moreover, this report represents the first occurrence of this genus in the Argentine Chacoan region.Fil: Hamann, Mónika Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: León Règagnon, Virginia. Universidad Nacional Autónoma de México; MéxicoFil: Fernández, María Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gonzalez, Cynthya Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin