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.