Parasites (Monogenea) of tilapias Oreochromis niloticus and Coptodon rendalli (Cichlidae) in a river spring in Brazil

In the present study, we examined 30 individuals of introduced African cichlids, Oreochromis niloticus and Coptodon rendalli, collected in a river spring of the Pardo River, Paranapanema River basin, southeastern Brazil. Based on morphological and molecular analyses of the partial LSU rDNA gene, we identified four species of monogeneans, Cichlidogyrus tilapiae, C. thurstonae, C. mbirizei, and Scutogyrus longicornis on the gills of O. niloticus, whereas individuals of C. rendalli were infested only with C. papernastrema. This is the first record of C. mbirizei and C. papernastrema in tilapias from Brazil. The ecological consequences of the introduction of exotic species of tilapia such as O. niloticus and C. rendalli along with their monogenean parasites in a wild environment represented by a river spring are discussed. Our new molecular data on Cichlidogyrus and Scutogyrus contribute to the investigation of the phylogenetic interrelationships of these widely distributed genera of monogeneans since their species composition is still unsettled.

Molecular phylogeny of two Rhinoxenus species (Monogenea: Dactylogyridae) from the nasal cavities of serrasalmids (Characiformes: Serrasalmidae) from Brazil

The dactylogyrid genus Rhinoxenus (Monogenea: Dactylogyridae) is composed of specialized monogeneans infecting the nasal cavities of freshwater fishes from the Neotropical region. This taxon currently comprises 11 species and is easily distinguished from other monogeneans by the absence of the dorsal bar, ventral anchor with inconspicuous roots covered by a sclerotized cap, dorsal anchor greatly modified into a needle-like shape, and hook pair 2 located into bilateral lobes of the trunk. Specimens of Rhinoxenus euryxenus and Rhinoxenus paranaensis were found infecting the nasal cavities of Serrasalmus marginatus and Serrasalmus maculatus, respectively, from the Paraná River basin in Brazil. For the first time, molecular data of Rhinoxenus spp. were obtained and used as a basis for phylogenetic analyses of the genus. Furthermore, our findings represent the first record of R. paranaensis in Brazil.

Diversity of myxozoans parasitizing the catfish Rhamdia quelen (Siluriformes: Heptapteridae), in southeastern Brazil, based on morphological and molecular evidence

Rhamdia quelen is a commercially important fish in South America. During the survey of myxozoan infections in fishes from Pardo River, Paranapanema River basin, São Paulo State, Brazil, we describe three new species of Henneguya found parasitizing gills of R. quelen: Henneguya bagre n. sp., Henneguya breviscauda n. sp and Henneguya novaerae n. sp. The descriptions were based on myxospores morphology and small subunit ribosomal DNA partial sequences. Phylogenetic analysis showed a clade formed by species that parasitize Siluriformes, with Henneguya jundiai as a sister species of Henneguya bagre n. sp., Henneguya breviscauda n. sp and Henneguya novaerae n. sp. Our study indicates that the parasites infecting R. quelen belong to a lineage of myxozoans infecting Heptapteridae fishes. Using molecular and morphological characterization, the species were identified as new species for the genus Henneguya. Based on our analysis we recommend monitoring the presence of these parasites in farmed fishes, to analyze possible pathologies caused by them.

Taxonomy and Systematics of Two New Species of Myxobolus (Cnidaria: Myxobolidae) Parasitizing the Gills of Mugil curema (Mugilidae) from the Brazilian Coast

PURPOSE

We describe two new species of Myxobolus (Myxobolidae) found parasitizing Mugil curema from two locations in Brazil: Myxobolus curemae n. sp. from gill arch and rays and Myxobolus maceioensis n. sp. from gill lamellae.

METHODS

We based the descriptions on myxospore morphology, histology, and small-subunit ribosomal DNA sequences.

RESULTS

Myxospores of the two new species had similar morphology and morphometry but differed in spore body width and length, and ssrDNA sequences differed by 10.5%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a subclade formed by species that parasitize Mugiliformes, with M. maceioensis n. sp. as a sister species of Myxobolus episquamalis and Myxobolus bizerti, while there is a group of six species that are sister related to M. curemae n. sp. Our analysis was consistent with previous studies suggesting that orders of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae.

CONCLUSIONS

Myxobolus curemae n. sp. and M. maceioensis n. sp. are new species identified parasitizing M. curema.

Description of Two Novel Henneguya (Cnidaria: Myxosporea) Infecting Curimatid Fish, Using Morphological, Histological, and Molecular Analyses

PURPOSE

We describe two new Henneguya spp. (Myxobolidae) found parasitizing Cyphocharax modestus from Pardo river, Paraná river basin, municipality of Botucatu, São Paulo State, Brazil: Henneguya fastigata n. sp. from gill lamellae and Henneguya pardensis n. sp. from gill arches. We based the descriptions on myxospore morphology, histology, and small subunit ribosomal DNA sequences.

METHODS

In this investigation, 50 specimens of Cyphocharax modestus were examined between July and December 2020 for myxozoan infections. Morphological characterization was based on the mature myxospores. The small subunit ribosomal DNA sequences were used for molecular and phylogenetic study.

RESULTS

Phylogenetic analysis provided the evolutionary position of these new species with other myxobolids species. Myxospores of the two species had similar morphology and morphometrics, but differed in spore body width and length, and ssrDNA sequences differed by 7.2%. These data supported the diagnosis of the parasites as distinct and novel species. The phylogenetic analysis showed a well-supported subclade formed by species that parasitize curimatid fishes, with Henneguya gilbert as a sister species of Henneguya fastigata n. sp., and Henneguya pardensis n. sp. as a sister species of both species.

CONCLUSION

Our analysis was consistent with previous studies suggesting that orders and families of the hosts are strongly correlated with phylogenetic signals in the Myxobolidae. These are the first species of myxozoans described in the Pardo river.

Characithecium spp. (Monogenea: Dactylogyridae) from Astyanax bimaculatus (Characiformes: Characidae) in Northeast Brazil, with Description of a New Species

PURPOSE

To date, seven species of Characithecium Mendonza-Franco, Reina and Torchin, 2009 (Monogenea, Dactylogyridae) are valid, parasitizing mainly fishes of the family Characidae (Characiformes) in the Neotropical region. During a parasitological study of fishes in the Batateiras River and Carás stream, Ceará state, Brazil, two species of Characithecium were collected from the gills of Astyanax bimaculatus Linnaeus, 1758 (Characidae). The purpose of the present study is to describe a new species of monogenean of the genus Characithecium and report Characithecium costaricensis Mendoza-Franco, Reina and Torchin, 2009 in A. bimaculatus, in Brazil.

METHODS

Monogeneans were isolated from the gills and stored in 70% ethanol, mounted in Gray and Wess' medium or and in a mixture of glycerin ammonium picrate (GAP) to study sclerotized structures. Morphological analyses were performed with a computerized image analysis system with differential interference contrast (DIC). The drawings were obtained with the aid of a camera lucida mounted on a Leica DMLS microscope.

RESULTS

Characithecium bifurcuprolatum n. sp. differs from its congenerics by the morphology of the accessory piece having a ventral unit articulated to cirrus base, a non-articulated dorsal and mid-ventral, and a sclerotized vaginal vestibule. Characithecium costaricensis was described from Astyanax aeneus (Günther, 1860) (Characidae) in Central America, and the present finding represents a new geographical and host records in Brazil. Furthermore, we observed the presence of a membrane at the base of the cirrus not mentioned in the original description.

CONCLUSION

Our findings increase to eight the number of known species of the genus Characithecium parasitizing characids in neotropics. We verified some additional characteristics present in the two species studied, such as the presence of a membrane at the base of the cirrus, an accessory piece with two subunits (an articulated ventral and a dorsal non-articulated) and the presence of sclerotized vaginal vestibule.

Three new species of Creptotrema (Trematoda, Allocreadiidae) with an amended diagnosis of the genus and reassignment of Auriculostoma (Allocreadiidae), based on morphological and molecular evidence

Diversity of Creptotrema was investigated using morphological and molecular tools, including data for Creptotrema creptotrema (type-species). Three new species, parasites of Brazilian fishes, are described: Creptotrema conconae n. sp. (type-host, Imparfinis mirini Haseman), Creptotrema schubarti n. sp. (type-host, Characidium schubarti Travassos) and Creptotrema megacetabularis n. sp. (type-host, Auchenipterus osteomystax (Miranda Ribeiro)). The diagnosis of the genus was amended to include new features. The new species differ from each other mainly in terms of body shape, relative sucker size, and testes position. DNA sequences were obtained from Creptotrema spp. from Brazil, including 28S, ITS and COI. Genetic divergences among the new species and C. creptotrema varied from 2.1 to 5.2% (21–49 bp) for 28S, and 6.6 to 16.4% (21–45 bp) for COI. Phylogenetic analysis (28S) placed the newly generated DNA sequences of Creptotrema in a clade (Creptotrema clade sensu stricto) composed of C. creptotrema, the new species described herein, and all species previously described as Auriculostoma, revealing that Auriculostoma is best interpreted as a synonym of Creptotrema based on the principle of priority of zoological nomenclature. Creptotrema funduli, the single sequence of the genus previously available, was not grouped within the Creptotrema clade sensu stricto, suggesting the need for reevaluation of the taxonomic status of this species. Our results showed that Creptotrema represents a monophyletic genus of trematodes widely distributed across the Americas, which currently comprises 19 valid species of parasites of teleosts and anurans.

Visceral mycobacteriosis in amphibians from the Brazilian Caatinga region

Emerging infectious diseases in wild animals related to humans have received greater attention in recent years. Mycobacteriosis is a bacterial disease of animal and human importance. Mycobacterium gordonae infects the skin and internal organs of free-ranging amphibians and is considered the least pathogenic member of the Mycobacteriaceae to humans. However, information about its infection and pathogenesis in wild amphibians is still lacking. A total of 1306 amphibian specimens belonging to 6 families, 12 genera, and 21 species were collected and dissected during a helminthological survey of 7 municipalities in southern Ceará state, Caatinga (eco)region, northeast Brazil. Of these, 17 specimens (0.76%), belonging to 2 families and 4 species (Leptodactylus macrosternum, n = 2; L. vastus, n = 10; Pseudopaludicola pocoto, n = 2; Rhinella jimi, n = 3), presented infections that consisted of calcification nodules in the coelomic cavity, kidney, liver, lung, gut, and pancreas. The nodules were examined by histopathology and PCR. The bacteria were identified as M. gordonae by molecular analyses. Infected animals presented with hepatocellular vacuolar degeneration, karyolysis, and karyorrhexis, hepatic portal congestion, hemorrhage, mononuclear cellular infiltration, melanomacrophage center hyperplasia, and granulomas in varying stages of development with intralesional acid-fast bacilli. This study is the first report of M. gordonae in these amphibian species, in which results of molecular analyses confirmed the presence of M. gordonae in natural environments and histopathology confirmed the typical lesion of mycobacteriosis in amphibians from northeastern Brazil.

Three New Species of Cosmetocleithrum (Monogenea: Dactylogyridae) Gill Parasites of Trachelyopterus galeatus (Siluriformes: Auchenipteridae) in Southeastern Brazil

PURPOSE

To describe three new species of Cosmetocleithrum in the gills of Trachelyopterus galeatus (Siluriformes, Auchenipteridae) from Aguapeí River, Upper Paraná River basin, São Paulo State, Brazil.

METHODS

Fifty-three specimens of T. galeatus were captured in the mouth of the Aguapeí River from August 2013 to June 2014. Monogeneans were mounted unstained in Hoyer's and Gray and Wess's medium.

RESULTS

Cosmetocleithrum spathulatum sp. n., Cosmetocleithrum baculum sp. n., and Cosmetocleithrum galeatum sp. n. differ from all known congeneric species mainly in the morphology of the accessory piece (i.e. spatulate-shaped, claviform, and a straight rod with hook-shaped distal portion, respectively). Also, the three new species share hooks with different sizes with hooks pairs 5 and 7 bigger than others and with an erect delicate point, inconspicuous thumb, longer shaft, and slender shank.

CONCLUSIONS

To date, 18 species of Cosmetocleithrum were recognised parasitizing siluriforms in the Neotropical region. The present study expands the number to 21 species, however, despite this increase, the number of known taxa of monogeneans in neotropics is far from representing the ideal situation.

New insights on the diversity of Brazilian anuran blood parasites: With the description of three new species of Hepatozoon (Apicomplexa: Hepatozoidae) from Leptodactylidae anurans

The Amphibia are considered the most threatened vertebrate class globally, yet in Brazil they are also one of the more diverse and species rich groups. Although, in recent years there has been strong focus on amphibian related research, their parasites have not received the same attention. In Brazil, only a single species of Hepatozoon, namely H. leptodactyli (Lesage, 1908) Pessoa, 1970, has been described from anuran hosts. The present study aimed to describe three new species of Hepatozoon parasitising Leptodactylus labyrinthicus and Leptodactylus latrans from Mato Grosso State, Brazil. From 66 anurans screened for haemogregarines, four belonging to the Leptodactylidae were found positive for species of Hepatozoon. Based on the morphological analysis of peripheral blood gamonts and spleen and liver tissue meronts, three different morphotypes of Hepatozoon spp. were identified. Morphotype 1 (M1) and morphotype 2 (M2) in L. labyrinthicus and morphotype 3 (M3) in L. latrans. Molecular data based on partial 18S rDNA sequences revealed an interspecific divergence, between the species ranging from 0.43% to 1.16%. Phylogenetic analysis recovered isolates from the present study monophyletic with other isolates from Brazilian reptile and anuran hosts, sister to a clade comprising species isolated from African, North American and European reptile and anuran host species. Thus, using morphological and molecular analysis three new species infecting Brazilian Leptodactylidae anurans were identified and described. This study increases the knowledge of Brazilian anurans blood parasites and demonstrates the importance of using integrative approaches for diagnosis of hemoparasites.

•

Diversity and phylogenetic relationship of haemogregarines from Brazilian anurans.

•

Description of a three new species of Hepatozoon from Brazilian anurans.

•

First report of species of Hepatozoon descriptions using both morphological and molecular approaches from Brazilian anurans.

•

Merogonic data of Hepatozoon spp. infection on Brazilian anurans.

A new species, Dactylosoma piperis n. sp. (Apicomplexa, Dactylosomatidae), from the pepper frog Leptodactylus labyrinthicus (Anura, Leptodactylidae) from Mato Grosso State, Brazil

The Dactylosomatidae Jakowska and Negrelli, 1955 are one of four families belonging to adeleorinid coccidia and comprise the genera Babesiosoma Jakowska and Nigrelli, 1956 and Dactylosoma Labbé, 1894. These blood protozoa occur in peripheral blood of lower vertebrates, and are commonly reported parasitising amphibians. The present study describes Dactylosoma piperis n. sp. from the pepper frog Leptodactylus labyrinthicus (Spix, 1824) (Anura: Leptodactylidae), collected in 2018 at the municipality of Araguaiana, Mato Grosso State, Brazil, based on morphology of intra-erythrocytic trophozoite, primary and secondary merogonic stages and a molecular analysis (partial 18S rDNA). Dactylosoma piperis n. sp. forms a well-supported clade with other Dactylosomatidae. This is the first molecular characterization of a species of Dactylosoma from a Brazilian anuran.

Occurrence of Cyanobacteria and microcystins in hydroelectric reservoirs used for fish farming

Fish farming can have a negative impact on water quality and aquatic organisms due to emerging blooms of Cyanobacteria and the production of cyanotoxins. In this study, the effect of aquaculture in hydroelectric reservoirs in Brazil was evaluated in six fish farms and in upstream and downstream water through analysis of the microbiome, Cyanobacteria and microcystin concentrations. Synechococcus and Microcystis were observed at all six locations, while Limnothrix was also observed abundantly at two locations. An increase in the relative abundance of Cyanobacteria inside the fish farms was observed at two locations, while an increase of Cyanobacteria was observed in downstream at five of the six locations. Microcystins were detected in significant and high values in all locations, with concentrations up to 1.59 μg/L. The trend in microcystin concentrations was mirrored in copy numbers of the mcyE gene (encodes microcystin synthetase) and presence of Microcystis, but not in any of the other observed cyanobacterial groups. In summary, the study shows that aquaculture production influenced the water microbiome inside and downstream the fish farms, and a direct correlation was found between mcyE gene copies, microcystin production and abundance of Microcystis, but not for the total abundance of Cyanobacteria.

A new species of Wallinia Pearse, 1920 (Digenea: Allocreadiidae), in Astyanax bimaculatus (Linnaeus, 1758) (Characidae) in Northeast Brazil, based on morphology and DNA sequences

Wallinia caririensis n. sp. is described from the intestine of Astyanax bimaculatus (Linnaeus, 1758) (Characidae) collected in the Batateiras River in the municipality of Crato, Ceará state, Brazil. The description was based on integrative taxonomy approach using DNA sequences from the D1-D3 domains of the 28S rDNA gene. The new species was confirmed through the phylogenetic analysis of the 28S rDNA gene, which showed that Wallinia caririensis n. sp. is a sister taxon of Wallinia brasiliensis (Dias, Müller, Almeida, Silva, Azevedo, Pérez-Ponce de León, and Abdallah, 2018, and Wallinia anindoi Hernández-Mena, Pinacho-Pinacho, García-Varela, Mendonza-Garfias, and Pérez-Ponce de León, 2019), a species which parasitizes Astyanax fasciatus (Cuvier, 1819), A. lacustris (Lucena and Soares, 2016) in Brazil, and A. aeneus (Günther, 1860) in Mexico, with genetic divergences of 2% and 3%, respectively. The new species can be distinguished morphologically from its congeners by possessing large body size (length and width) and tapered extremity in the posterior end of the body, eyespots are present at the pharynx level, and vitelline follicles reach up to the half distance between the posterior testis and the extremity of the body, by having larger testes distributed in coincident zones (i.e., contiguous) and non-operculated eggs (a conspicuous characteristic in W. brasiliensis). To date, species of this genus have already been described in freshwater fishes from Mexico, Costa Rica, Venezuela, and Southeastern Brazil. The species described in this study consists of the second species parasitizing characids in Brazil, and the first record in Northeastern Brazil. This finding fills a gap and expands the biogeographic distribution of the genus Wallinia in South America.

Anatomopathological lesions of infection caused by Platynosomum illiciens (Braun, 1901) in Neotropical primates kept in captivity

This study described the hepatobiliary anatomopathological lesions associated with trematode Platynosomum illiciens parasitism in Neotropical primates kept in captivity. In the evaluated organs, we observed portal fibrosis, biliary epithelial hyperplasia, and inflammatory reaction with a predominance of lymphocytes and plasmocytes, and in some cases infiltration of eosinophils and neutrophils.

Ascocotyle longa (Digenea: Heterophyidae) infecting dolphins from the Atlantic Ocean

We report for the first time the infection of dolphins with Ascocotyle longa found in the intestines of three different species, Sotalia guianensis, Steno bredanensis, and Tursiops truncatus gephyreus, which were found washed ashore along the southeastern and southern Brazilian coast. The worms were identified based on morphological and molecular data using the 28S rDNA gene and the COI gene. Specimens of A. longa from the pinniped Otaria flavescens were also analyzed. As the first isolation of A. longa from cetaceans, the present study increases the distribution area and range of definitive hosts of this trematode, and provides new molecular data to complement the phylogeny of the group in future studies, thus contributing to the scientific knowledge of this potentially zoonotic parasite.

Helminth Parasites of Three Anuran Species during Reproduction and Drought in the Brazilian Semiarid Caatinga Region

We investigated the mean abundance of helminths and analyzed helminth composition and structure at the infracommunity and component community levels for 3 anuran species (Pleurodema diplolister, Rhinella jimi, and Rhinella granulosa) from the Caatingas, a semiarid Brazilian region characterized by accentuated seasonality and unpredictability of rains. Data were collected during the reproductive period and during drought, when P. diplolister estivated buried underground but R. jimi and R. granulosa remained foraging actively. We expected higher parasitological parameters during the reproductive period when compared to drought for these 3 anurans. We also expected higher parasite infection in the Rhinella species and higher similarity between their helminth parasite communities when compared to the estivating species, P. diplolister. Contrary to our hypothesis, the season was not related to parasite community structure. As predicted, the Rhinella toads shared more similar species composition of parasite communities. These similarities in the composition of the parasite community between Rhinella species could be due to similar temporal/spatial patterns of activity and phylogenetic proximity. Pleurodema diplolister hosted a more restricted helminth fauna, a result that might be associated with estivation restricting the temporal window available to acquire parasites. This study also presents new helminth fauna records for R. jimi and P. diplolister, and the first helminth fauna record of R. granulosa from the Caatingas in semiarid Brazil.

Molecular and morphological characterization of the metacercariae of two species of diplostomid trematodes (Platyhelminthes, Digenea) in freshwater fishes of the Batalha River, Brazil

The Diplostomidae include a large group of flatworms with complex life cycles and are frequently found parasitizing the eyes and central nervous system of freshwater fishes. The morphological identification of the metacercariae at species level is not always possible. Thus, molecular tools have become essential to assist in the parasite species determination. This study was aimed at describing two diplostomid metacercariae found in freshwater fish in São Paulo, Brazil, based on morphological characters and in the genetic characterization of COI sequences. Our results showed that the two recognized taxa (Tylodelphys sp. and Diplostomidae gen. sp.) appear to be different from the species already described in South America. Tylodelphys sp. differs morphologically from Tylodelphys xenopi, T. mashonense, T. jenynsiae, and T. scheuringi. The metacercariae of T. clavata and T. conifera are smaller than Tylodelphys sp., while T. podicipina is larger than the metacercariae described here. The phylogenetic analysis of COI sequences yielded Tylodelphys sp. as the sister species of Tylodelphys sp. 4, a species reported from the brain of the eleotrid Gobiomorus maculatus in Oaxaca, Mexico. The metacercariae identified as Diplostomidae gen. sp. are morphologically different from the known diplostomid metacercariae and did not match with other diplostomid sequences available. Diplostomidae gen. sp. is recovered as the sister species of Diplostomum ardeae. Although the morphological evidence and the COI sequences differentiate the metacercariae found, the absence of adult specimens of both species precludes the specific designation. This is one of the first papers that use an integrative taxonomy approach to describe the species diversity of diplostomid trematodes in Brazil.

New data on Myxobolus imparfinis (Cnidaria, Myxosporea): host, distribution, and ultrastructural morphology

A mass of free myxozoan spores was found in the gill filaments of specimens of Cetopsorhamdia iheringi Schubart and Gomes, 1959, popularly known as "three-barbeled catfishes" (Heptapteridae, Siluriformes) collected in streams of the Middle Paranapanema River, Upper Paraná River basin, in the state of São Paulo, Brazil. Morphological and molecular analysis identified the spores as Myxobolus imparfinis Vieira, Tagliavini, Abdallah and Azevedo, 2018. The ultrastructural morphology of this parasite is described here for the first time. Differences were observed in the number of coils of the polar filament as well as some organelles not previously described for this species. Asynchronous development was also observed, with the presence of both mature and immature spores. This is the first report of a myxozoan parasitizing C. iheringi and the first geographical record of myxozoan parasites in streams of the Middle Paranapanema River. The new data improve the original description of the species and add to the knowledge of host-parasite interactions and distribution.

Skin nodules associated with parasitism with Henneguya sp. (Cnidaria: Myxosporea) in the neotropical fish Cyphocharax modestus

A new myxozoan species, Henneguya sp., is described based on material from skin of Cyphocharax modestus. Mature myxospores are were elongate and ellipsoidal, measuring 21.4 ± 1.2 (19.4-23.2) μm in total length, 5.1 ± 0.3 (4.5-5.8) μm in width, 11.9 ± 0.5 (10.9-12.7) μm in body length and 9.6 ± 0.7 (8.4-10.5) μm in length of the caudal process. The polar capsules were elongated and had unequal sizes, with length of 5.1 ± 0.4 (4.5-6.0) μm and 5.6 ± 0.4 (4.9-6.3) μm for smaller and larger respectively and width of 1.8 ± 0.2 (1.4-2.0) μm. The larger polar capsule had 8 turns in polar filament while the smaller polar capsule had 5 turns in polar filament. The macroscopic analysis revealed the presence of large nodules, which were located before and after the dorsal fin of the hosts. The histopathological analysis showed the development of nodules filled with plasmodia, surrounded by loose connective tissue, developed in the dermis of the skin. Many cysts containing countless spores, as well as free spores, were located in the dermis and hypodermis of the hosts, causing the disorganization of the connective tissue that is responsible for the support. This is the first record of a Henneguya species in C. modestus.

Molecular phylogenetic position of Haplometroides intercaecalis (Digenea, Plagiorchiidae)

Three valid species of Haplometroides Odhner, 1910 parasitise snakes and amphisbaenians from South America. This study provides additional data on morphometric and molecular phylogenetic position inferred from the nuclear ribosomal gene 28S (partial). DNA sequences were isolated from Haplometroides intercaecalis Silva, Ferreira and Strüssmann, 2007 found in one specimen of Phalotris matogrossensis Lema, D'Agostini and Cappellari, 2005. Five digenean specimens were recovered from the esophagus of this snake, and four specimens were used for morphometrical studies and one specimen for molecular analysis. Phylogenetic analysis using maximum likelihood and Bayesian methods was conducted with sequences available for the order Plagiorchiida and its phylogenetic position places H. intercaecalis among the brachycoeliids Brachycoelium (Dujardin, 1845) Stiles and Hassall, 1898 and Parabrachycoelium Pérez-Ponce de León, Mendoza-Garfias, Razo-Mendivil and Parra-Olea, 2011, and the mesocoeliid Mesocoelium Odhner, 1910, not closely related to plagiorchids as expected. Due to morphological differences among these families, it may be necessary to create a new family to accommodate Haplometroides spp. However, more genera/taxa as well as other molecular markers should be added in future studies to confirm our results and resolve this matter. This is the first phylogenetic positioning of digeneans of the genus Haplometroides, contributing to the systematic analysis of the helminthological biodiversity of Neotropical snakes.

A new species of Cacatuocotyle (Monogenea, Dactylogyridae) parasitizing Astyanax spp. (Characiformes, Characidae) from Brazil, including molecular data and a key to species identification

The present study describes Cacatuocotyle papilionis n. sp. (Monogenea, Dactylogyridae) from the skin of the characid fishes Astyanax lacustris (Lütken, 1875) (=Astyanax altiparanae Garutti & Britski, 2000) and Astyanax fasciatus (Cuvier, 1819) (Characiformes, Characidae) from the Southeast of Brazil, supported by morphological and molecular data. The new species differs from all congeners, mainly due to the morphology of the ventral bar (resembling a butterfly), accessory piece, and the number of rings of the male copulatory organ (MCO), comprising a coiled tube with 4.5-5.5 counterclockwise rings. The first molecular data for this monogenean genus is provided in this study, using the partial sequences of the ribosomal gene (28S), as well as providing an identification key to the species.

Gastrointestinal helminths of two populations of wild pigeons (Columba livia) in Brazil

Abstract The present study analyzed gastrointestinal helminth communities in 265 wild pigeons (Columba livia) living in the municipalities of São Paulo and Tatuí, state of São Paulo, Brazil, over a one-year period. The birds were caught next to grain storage warehouses and were necropsied. A total of 790 parasites comprising one nematode species and one cestode genus were recovered from 110 pigeons, thus yielding an overall prevalence of 41.5%, mean intensity of infection of 7.2 ± 1.6 (range 1-144) and discrepancy index of 0.855. Only 15 pigeons (5.7%) presented mixed infection. The helminths isolated from the birds were Ascaridia columbae (Ascaridiidae) and Raillietina sp. (Davaineidae). The birds’ weights differed according to sex but this did not influence the intensity of infection. The overall prevalence and intensity of infection did not differ between the sexes, but the prevalence was higher among the birds from Tatuí (47.8%). The gastrointestinal helminth community of C. livia was characterized in the two areas studied and parasite homogeneity was observed over the 12 months analyzed at both locations. These results make contributions to the current literature on health aspects of wild C. livia populations.

A new genus and two new species of dactylogyrid monogeneans from gills of Neotropical catfishes (Siluriformes: Doradidae and Loricariidae)

A new genus of dactylogyrid monogeneans (Ancyrocephalinae), Paracosmetocleithrum n. gen., is erected to accommodate P. trachydorasi n. sp. from Trachydoras paraguayensis (Siluriformes: Doradidae) in the Upper Paraná River basin, Brazil. The new genus differs from Neotropical dactylogyrids in the presence of a well-developed ornamentation in the middle portion of the ventral bar, and a sclerotized patch on the surface of the dorsal bar with an inconspicuous medial process that possesses two submedial projections arising from the tapered ends of this patch. In addition, Demidospermus rhinelepisi n. sp. is described from Rhinelepis aspera (Siluriformes: Loricariidae). The new species, which is the fifth species of the genus described from loricariids, can be differentiated from congeners by the possession of a sclerotized patch attached to the middle portion of the ventral bar, and by morphology of the accessory piece, which presents broad ends, tapering in the centre, rounded proximal end, distal end folding on both sides with folds extending to approximately ¾ of the accessory piece length. Molecular data on both new species are also provided and species composition of Demidospermus, recently revealed as polyphyletic by molecular studies including the present one, is discussed.

Chapiniella variabilis (Nematoda) parasitizing Chelonoidis carbonarius and C. denticulatus (Testudinidae) in the state of Piauí

Chapiniella variabilis (Chapin, 1924), a strongylid nematode, was collected parasitizing the large intestine of the tortoises Chelonoidis carbonarius (Spix, 1824) (Cc) and C. denticulatus (Linnaeus, 1766) (Cd) in the Zoobotanical Park of the municipality of Teresina, state of Piauí, Brazil. The taxonomic identification was based on morphological and morphometric features, using bright-field and scanning electron microscopy. The present study adds new observations on the morphology, mainly relating to the mouth papillae, external and internal leaf-crown elements, excretory pore, deirids and male and female posterior end. The parasitic indices of prevalence (P), mean intensity (MI), mean abundance (MA) and range of infection (RI) of C. variabilis in these two tortoise species were: P = 100%, MI = 833.3, MA = 833.3, RI = 500-1,500 (Cc); P = 100%, MI = 472.2, MA = 472.2, RI = 333-500 (Cd). This record expands occurrences of C. variabilis to a new host, C. carbonarius, and to another state in Brazil, in the Neotropical region of South America. Adjustment to host management with the aim of improving hygiene and health conditions is suggested.

Ecological implications of floods on the parasite communities of two freshwater catfishes in a Neotropical floodplain

The parasite communities of two freshwater catfishes (Auchenipterus osteomystax and Trachelyopterus galeatus) were analyzed during the dry and rainy seasons in a Neotropical floodplain. The nature of river-floodplain systems places specific demands on parasite community structure, due to changes in the host environment. It was therefore hypothesized that flood conditions lead to an increase in the richness and abundance of fish parasites in the rainy season at the mouth of Aguapeí River floodplain. The Auchenipterus osteomystax parasite community was richer (11 vs. eight) in species than T. galeatus, although the latter exhibited a greater parasite burden (F1,108 = 126.99, P<0.0001). During the rainy season both host species demonstrated high levels of parasitism (least squared means ± SE = 1.69 ± 0.05 vs. 1.34 ± 0.05; F1,108 = 21.45, P<0.0001). Differences were found in the composition of the parasite species and the proportion of parasites for each host species and between each seasonal period. Flood conditions during the rainy season caused a change in the composition and structure of the parasitic communities. The results corroborate the hypothesis that floods are one of the most significant influences on shaping the parasite communities of fish in floodplains. Our greatest concern is the reduction these dynamics and effects bring about on local biota and, consequently, in host-parasite interaction. We would therefore like to take this opportunity to warn environmental agencies and hydroelectric companies about the importance of the conservation of the diversity of this location.

Prevalence and distribution of Angiostrongylus cantonensis (Nematoda, Angiostrongylidae) in Achatina fulica (Mollusca, Gastropoda) in Baixada Santista, São Paulo, Brazil

INTRODUCTION

Angiostrongylus cantonensis is causes eosinophilic meningoencephalitis in humans. Worldwide expansion of this nematode is linked to the dispersion of their hosts. This study aimed to determine the prevalence of A. cantonensis infection in Achatina fulica in the nine municipalities that make up Baixada Santista, São Paulo, Brazil.

METHODS

Angiostrongylus cantonensis larvae were analyzed using optical microscopy. We performed polymerase chain reaction and restriction fragment length polymorphism using restriction endonuclease ClaI, directed to the internal transcribed spacer region 2 of A. cantonensis larval DNA.

RESULTS

Of the 540 snails analyzed, 117 (21.7%) were infected by A. cantonensis. For morphological and morphometric analyses, 60 larvae were used. Second-stage larvae were, on average, 358.2µm long and 26.4µm wide, while third-stage larvae were, on average, 450µm long and 21.12µm wide. The tails of the larvae ended in a fine tip.

CONCLUSIONS

All municipalities comprising Baixada Santista had A. fulica that were naturally infected with A. cantonensis. All of the observed characteristics were typical of the species.

Helminth fauna of Leptodactylus syphax (Anura: Leptodactylidae) from Caatinga biome, northeastern Brazil

Leptodactylus syphax is distributed in central, southeastern and northeastern Brazil, eastern Bolivia and southern Paraguay, occupying open areas and rock outcrops, in rock cavities and termite burrows. We collected 21 frogs from the Caatinga region of the state of Ceará, northeastern Brazil, and 7,021 helminths were recovered from 18 of these hosts (overall prevalence = 85.7%). Six helminth taxa were recovered, as follows: Aplectana membranosa (n = 3,756); Schrankiana formosula (n = 3,176); larvae of Physaloptera sp. (n = 43); unidentified nematode larvae (n = 7); digenean metacercariae of Lophosicyadiplostomum sp. (n = 2); and cystacanths of Acanthocephala (n = 37). The similarity of helminth composition between L. syphax from the Caatinga and other species of the L. fuscus group showed that some anurans were clustered according to parasite species and others according to geographic locality. This study presents new helminth records for the Neotropical region, thus helping in understanding the pattern of species distribution, and it increases the knowledge of parasites associated with amphibians.

Ectoparasites of Nile tilapia (Oreochromis niloticus) in cage farming in a hydroelectric reservoir in Brazil

For this study, we performed a parasitological analysis of cage-cultured Nile tilapia (Oreochromis niloticus) from the Água Vermelha Reservoir, Southeastern Brazil, and verified relationships with limnological data, seasonality, and fish growth phase. From March 2010 to March 2011, sixty-three specimens of O. niloticus in three growth phases (i.e., initial, intermediate, and final) were collected. All fish specimens were infested with at least one ectoparasite species (prevalence = 100%). Five species of protozoans (Trichodina compacta, Trichodina magna, Ichthyophthirius multifiliis, Piscinoodinium pillulare, and Epistylis sp.) and five species of monogenoids (Cichlidogyrus halli, Cichlidogyrus thurstonae, Cichlidogyrus sp. 1, Scutogyrus longicornis, and Gyrodactylus sp.) were observed. The abundance of Trichodina spp. and the prevalence of Epistylis sp. were higher in the dry season, and the prevalence of C. halli was higher in the rainy season. For the majority of ectoparasites found in this study, fish in the intermediate and final phases had higher parasitism rates than those in the initial phase. The data presented may help fish farmers to understand the parasite dynamics of the fish species studied in cage-farming systems.

Austrodiplostomum compactum metacercariae (Digenea: Diplostomidae) in Schizodon intermedius (Characiformes: Anostomidae) from Jurumirim reservoir, Brazil

This study reports the occurrence of Austrodiplostomum compactum metacercariae in the freshwater fish Schizodon intermedius (ximborê/piava) from a Neotropical reservoir in the Paranapanema River, state of São Paulo, Brazil. From a total of 75 fish collected, we found 38 infected with A. compactum metacercariae (prevalence = 50.67%) in the eyes. The mean intensity of infection and mean abundance were 9.05 ± 4.26 (1-155) and 4.59 ± 2.20 (0-155), respectively. Poulin's Discrepancy Index was 0.87 and four specimens presented more than 10 metacercariae in their eyes. No correlation was observed between parasite abundance and standard length, total weight and condition factor (p>0.05). These metacercariae are reported for the first time in S. intermedius.

First record of Paratanaisia bragai (Digenea: Eucotylidae) in blue and gold macaw (Ara ararauna)

Abstract The aim of this study was to provide the first report on a new host for the digenean Paratanaisia bragai in the caninde macaw Ara ararauna along with the pathological aspects of the infection in the new host. The microscopic findings revealed the presence of granulomatous interstitial nephritis. This study contributes towards knowledge of parasitism by P. bragai in A. ararauna, and emphasizes the need to use best practices in wildlife conservation parks.

Morphological and Molecular Characterization of Clinostomum detruncatum (Trematoda: Clinostomidae) Metacercariae Infecting Synbranchus marmoratus

A complete morphological description, supported by molecular data, of Clinostomum detruncatum metacercariae is reported in this study. The metacercariae were found infecting Synbranchus marmoratus from the Paraná River, municipality of Guaíra, Paraná State, Brazil. The taenioidean uterus is the main morphological characteristic of this species. Both neighbor-joining (NJ) and maximum likelihood (ML) trees showed 2 clear separate clusters grouping together the species from the Palearctic region (Clinostomum complanatum, Clinostomum cutaneum, Clinostomum phalacrocoracis, Clinostomum philippinense) and those from the Nearctic/Neotropical regions (Clinostomum marginatum, Clinostomum tataxumui, C. detruncatum, Clinostomum sp. 7). The latter clade is divided into 2 subclades grouping species from North America and Mexico (C. marginatum and C. tataxumui), and those from Brazil (C. detruncatum and Clinostomum sp. 7).

How Many Parasites Species a Frog Might Have? Determinants of Parasite Diversity in South American Anurans

There is an increasing interest in unveiling the dynamics of parasite infection. Understanding the interaction patterns, and determinants of host-parasite association contributes to filling knowledge gaps in both community and disease ecology. Despite being targeted as a relevant group for conservation efforts, determinants of the association of amphibians and their parasites in broad scales are poorly understood. Here we describe parasite biodiversity in South American amphibians, testing the influence of host body size and geographic range in helminth parasites species richness (PSR). We also test whether parasite diversity is related to hosts’ phylogenetic diversity. Results showed that nematodes are the most common anuran parasites. Host-parasite network has a nested pattern, with specialist helminth taxa generally associated with hosts that harbour the richest parasite faunas. Host size is positively correlated with helminth fauna richness, but we found no support for the association of host geographic range and PSR. These results remained consistent after correcting for uneven study effort and hosts’ phylogenic correlation. However, we found no association between host and parasite diversity, indicating that more diversified anuran clades not necessarily support higher parasite diversity. Overall, considering both the structure and the determinants of PRS in anurans, we conclude that specialist parasites are more likely to be associated with large anurans, which are the ones harbouring higher PSR, and that the lack of association of PSR with hosts’ clade diversification suggests it is strongly influenced by ecological and contemporary constrains.

Endohelminths in Cichla piquiti (Perciformes, Cichlidae) from the Paraná River, São Paulo State, Brazil

Fifty specimens of Cichla piquiti were collected from the Paraná River downstream of the Ilha Solteira Hydroelectric Power Station in Brazil and surveyed for endohelminth parasites. All fish were parasitised by at least one helminth species (overall prevalence [P] = 100%). Eight parasite taxa were present: the nematode Procamallanus (Procamallanus) peraccuratus in the intestines; third-stage larvae of the anisakids Contracaecum sp. and Hysterothylacium sp. in the visceral cavity, mesentery and serosa of the stomach and intestines and on the liver and spleen; the trematodes Austrodiplostomum compactum in the eye (metacercariae) and Genarchella genarchella in the stomach; and the cestodes Proteocephalus macrophallus, Proteocephalus microscopicus, and Sciadocephalus megalodiscus in the intestines. Hysterothylacium sp. larvae (P = 86%) and P. microscopicus (P = 74%) were the most prevalent parasites. Anisakids were more prevalent and abundant in the dry season. A negative correlation between the abundances of Hysterothylacium sp. and P. microscopicus was observed, suggesting a competitive/antagonistic relationship between these parasites. Cichla piquiti represents a new host for four parasite species. These new records significantly increase the list of parasites of C. piquiti, contributing to the knowledge of the host-parasite relationship and the geographical distribution of these helminths.

Monogeneans (Dactylogyridae) parasitizing gills of Salminus hilarii from a Neotropical reservoir, Brazil

With the aim of creating an inventory of the metazoan gill parasites of Salminus hilarii in the Taquari River, state of São Paulo, Brazil, five species of monogeneans (Anacanthorus contortus, A. bicuspidatus, Annulotrematoides parisellei, Jainus iocensis and Tereancistrum arcuatus) are reported the first time for this host. A total of 28 fish were sampled quarterly between April 2011 and January 2012, with 10 hosts in a lentic ecosystem and 18 in a lotic ecosystem. Quantitative ecological descriptors (prevalence, intensity of infestation and abundance) were calculated for the purpose to comparing the two ecosystems sampled (lentic and lotic ecosystems). However, no quantitative difference between the lentic and lotic ecosystems was observed. The present study has made available a checklist for species of the genus Anacanthorus and their hosts and geographical distribution in the Neotropical region up to the present time.

Parasitism by Sphincterodiplostomum musculosum (Digenea, Diplostomidae) metacercariae in the eyes of Steindachnerina insculpta (Characiformes, Curimatidae)

New occurrences and effects of parasitism by metacercariae in fish eyes have recently been discussed in many studies. The aim of the present study was to evaluate the infection levels of the eye flukes Sphincterodiplostomum musculosum Dubois, 1936 (metacercariae) in Steindachnerina insculpta (Fernádez-Yépez, 1948) from three ecosystems under the influence of the Jurumirim reservoir (Paranapanema, Taquari and Veados Rivers). A total of 174 fish specimens were sampled between April 2011 and April 2012. There were high levels of infection by S. musculosum metacercariae in the eyes of S. insculpta from all the sampled ecosystems, thus presenting broad geographical distribution. The histological analyses revealed that the metacercariae were apparently lodged behind the retina. The smaller fish from the Taquari River were less parasitized by metacercariae than the adults. This pattern can be explained by the cumulative effect of parasitism, as demonstrated by the positive correlation between the abundance of metacercariae and fish body size.

New record of Pelecitus sp. (Nematoda, Onchocercidae) as a parasite of Athene cunicularia (Strigiformes, Strigidae) in southeastern Brazil

The aim of this study was to report the burrowing owl Athene cunicularia as a new host for the filarid nematode Pelecitus sp. in southeastern Brazil for the first time, as well as reporting the occurrence of this nematode species in the body cavity, near the cervical air sac and lung region. This study contributes towards knowledge of parasitism in Brazilian wild birds and an anatomical region of the host as an infection site for Pelecitus sp.

Community ecology of metazoan parasites of the sairú Cyphocharax nagelii from the Peixe River

A total of 57 sairus (Cyphocharax nagelii) from the Peixe River, state of São Paulo, southeastern Brazil, were examined between April 2011 and February 2012. Eleven species of metazoan parasites were collected and identified: Palombitrema triangulum, Curvianchoratus hexacleidus, Curvianchoratus singularis, Sphincterodiplostomum musculosum, Contracaecum sp., Cacatuocotyle paranaensis, Cosmoxynemoides aguirrei, Amplexibranchius bryconis, Brasergasilus sp., Ergasilus sp. and Clinostomum sp. The monogenean P. triangulum was the most prevalent species (61.40%) with the highest mean intensity (4.88). The monogeneans C. hexacleidus and C. singularis, the digenean S. musculosum and the nematode Contracaecum sp. also showed high prevalence. Only S. musculosum presented significant correlation between the total body weight of the host and its abundance. The parasitic infracommunities had a mean Brillouin diversity (HB) of 1.165 ± 0.987 and the maximum diversity was 1.671. The sex and length of the hosts did not influence the abundance of any parasite species. The community of metazoans in C. nagelii from the Peixe River was characterized by high richness and low uniformity.

New host records and a checklist of fishes infected with Austrodiplostomum compactum (Digenea: Diplostomidae) in Brazil

This study reports the infection of fishes byAustrodiplostomum compactum metacercariae in the Chavantes reservoir, medium Paranapanema River, municipality of Ipaussu, São Paulo State, Brazil. Twenty-three fish species were analysed, and 13 were infected with A. compactum metacercariae (56.5%) in their eyes. The following six fish species are new hosts for this metacercaria:Crenicichla haroldoi (1/1), Eigenmannia trilineata (11/6), Hoplosternum littorale(11/1), Iheringichthys labrosus (17/2),Leporinus amblyrhynchus (11/1), and Piaractus mesopotamicus (3/1). These new species increase the number of Brazilian fish species infected with this parasite to 36. Based on these findings, we hypothesise that the metacercariae larval stage of the parasite has a low specificity for the second intermediate host (fish). The majority of fish species infected in Brazil belong to the Loricariidae and Cichlidae families. For the fish species with higher mean abundances in Brazil, six are non-native species, and currently, Plagioscion squamosissimus has the highest mean abundance. The majority of fish species infected with A. compactum in Brazil are concentrated in the Paraná basin, although this may be related to the distribution of researchers.

Parasitic infections of Piaractus mesopotamicus and hybrid (P. mesopotamicus xPiaractus brachypomus) cultured in Brazil

This study evaluated the occurrence of parasitic infections in the “pacu” fish Piaractus mesopotamicus and the “patinga” hybrid (P. mesopotamicus x Piaractus brachypomus) in the northwest of São Paulo State, Brazil. Fish from the following three fish farms were evaluated every two months: A, a hatchery and larviculture farm (n = 16 pacu / n = 19 patinga), B, a growout farm (n = 35 patinga) and C, a fee-fishing property (n = 28 pacu / n = 7 patinga). Thirty-five fish from each property were collected from February 2010 to February 2011 and subjected to parasitological analysis. The parasites found were the following:Mymarothecium viatorum, Anacanthorus penilabiatus, Notozothecium janauachensis (Dactylogyridae, Monogenea),Trichodina spp., Ichthyophthirius multifiliis, Chilodonella sp. (Protozoa), Myxobolus spp.,Henneguya spp. (Myxozoa), Rondonia rondoni, Contracaecum sp. (Nematoda), and Dolops carvalhoi(Crustacea). Of the fish examined, 62.9% from “A” and 100% from “B” and “C” were infested with at least one parasite species. Pacu fish (n = 44) showed a higher susceptibility to Anacanthorus penilabiatus infestations, whereas patinga (n = 61) were more susceptible to Mymarothecium viatorum (p < 0.05). Appropriate fish handling (nutrition, transport and storage), in conjunction with monitoring of water quality, can reduce the stress to which the farmed fish are exposed and is essential for pathogen control.

Sphincterodiplostomum musculosum (Digenea, Diplostomidae) infecting Steindachnerina insculpta(Characiformes, Curimatidae) in the Chavantes Reservoir, Southeastern Brazil

This study aimed to report the infection bySphincterodiplostomum musculosum metacercariae inSteindachnerina insculpta from the Chavantes Reservoir, medium Paranapanema River, municipality of Ipaussu, State of São Paulo, Brazil. Thirty specimens of S. insculpta were collected and 29 were infected with S. musculosum metacercariae (prevalence = 96.67%) in the eyes and visceral cavity. The mean intensity of infection and abundance were 96.6 ± 29.41 (7-846) and 93.3 ± 28.6 (0-846), respectively. Positive correlation was observed between parasite abundance in the eyes and standard length (rs = 0.5, p = 0.005), total weight (rs = 0.649, p = 0.0001), and condition factor (rs = 0.439, p = 0.0154). The high parasitism rates by S. musculosummetacercariae in S. insculpta can be an indicative that this fish species is highly susceptible to infection by this diplostomid, and even reflect the presence of a large abundance of the intermediate host. Moreover,S. musculosum metacercariae are reported for the first time in S. insculpta.

Expanded description of Lamproglena monodi (Copepoda: Lernaeidae), parasitizing native and introduced fishes in Brazil

An occurrence of the copepod Lamproglena monodi Capart, 1944, parasitizing freshwater fishes in Brazil is presented, along with new morphological data. This crustacean was originally described parasitizing several cichlids in Africa. In the present study, the crustaceans were collected from the body surface and gills of two fish species native to Brazil [Astronotus ocellatus (Agassiz, 1831) and Cichla ocellaris Bloch and Schneider, 1801] and two introduced species [Oreochromis niloticus (Linnaeus, 1758) and Tilapia rendalli (Boulenger, 1897)]. The Brazilian specimens exhibited some morphometric intraspecies differences in relation to the specimens from Congo-Kinshasa and Egypt.