Detection and molecular characteristics of Pyelosomum cochlear (Digenea: Pronocephalidae) in the urinary bladder of the green sea turtle (Chelonia mydas) in the Northwest Pacific Ocean

The genus Pyelosomum consists of parasitic flukes occurring primarily in marine turtles; Pyelosomum cochlear Looss 1899 is the only species of this genus that parasitizes the urinary bladder. In this study, we detected flukes in the urinary bladders of 20 of 88 green sea turtles (Chelonia mydas) harvested in the Ogasawara Islands, in the Northwest Pacific Ocean. We identified the flukes as P. cochlear based on detailed morphological observations and comparisons of morphometric measurements of the species reported previously. Nucleotide sequences of nuclear ribosomal 18S and 28S regions and the mitochondrial cytochrome c oxidase subunit 1 (COI) region were determined for the flukes. The 18S and 28S phylogenetic trees revealed that the species of the superfamily Pronocephaloidea, including P. cochlear, constituted a single clade, but the species of the family Pronocephalidae did not constitute a single taxon. These findings suggest that Pronocephalidae is a paraphyletic group. The COI sequences of P. cochlear exhibited high genetic diversity, suggesting that they would be useful markers to understand the genetic structure of the parasite and its evolutionary relationship with the host turtle populations. This is the first study to provide the nucleotide sequences of Pyelosomum species; these data will be available for further molecular studies of this genus and its related taxa.

Effects of multiple stressors on northern leopard frogs in agricultural wetlands

Natural and anthropogenic stressors, including parasites and pesticides, may induce oxidative stress in animals. Measuring oxidative stress responses in sentinel species that are particularly responsive to environmental perturbations not only provides insight into host physiology but is also a useful readout of ecosystem health. Newly metamorphosed northern leopard frogs (Lithobates pipiens), a sentinel species, were collected from agricultural and non-agricultural wetlands exposed to varying concentrations of the herbicide atrazine. Significant effects of certain parasites' abundance and their interaction with atrazine exposure on frog oxidative stress were identified. Specifically, increased protein levels were detected in frogs infected with echinostome metacercariae. In addition, the nematode Oswaldocruzia sp. was significantly associated with increased thiol concentration and catalase activity. Significant parasite × atrazine interactions were observed for atrazine exposure and the abundance of Oswaldocruzia sp. on thiol, as thiol concentrations increased with parasite abundance at low atrazine localities and decreased in high atrazine wetlands. In addition, a significant interaction between the abundances of Oswaldocruzia sp. and gorgoderid trematodes on thiol concentrations was observed. These findings demonstrate that studies of oxidative stress on animals in natural ecosystems should account for the confounding effects of parasitism, particularly for amphibians in agricultural landscapes.

Parasitism and host behavior in the context of a changing environment: The Holocene record of the commercially important bivalve Chamelea gallina, northern Italy

Rapid warming and sea-level rise are predicted to be major driving forces in shaping coastal ecosystems and their services in the next century. Though forecasts of the multiple and complex effects of temperature and sea-level rise on ecological interactions suggest negative impacts on parasite diversity, the effect of long term climate change on parasite dynamics is complex and unresolved. Digenean trematodes are complex life cycle parasites that can induce characteristic traces on their bivalve hosts and hold potential to infer parasite host-dynamics through time and space. Previous work has demonstrated a consistent association between sea level rise and increasing prevalence of trematode traces, but a number of fundamental questions remain unanswered about this paleoecological proxy. Here we examine the relationships of host size, shape, and functional morphology with parasite prevalence and abundance, how parasites are distributed across hosts, and how all of these relationships vary through time, using the bivalve Chamelea gallina from a Holocene shallow marine succession in the Po coastal plain. Trematode prevalence increased and decreased in association with the transition from a wave-influenced estuarine system to a wave-dominated deltaic setting. Prevalence and abundance of trematode pits are associated with large host body size, reflecting ontogenetic accumulation of parasites, but temporal trends in median host size do not explain prevalence trends. Ongoing work will test the roles of temperature, salinity, and nutrient availability on trematode parasitism. Parasitized bivalves in one sample were shallower burrowers than their non-parasitized counterparts, suggesting that hosts of trematodes can be more susceptible to their predators, though the effect is ephemeral. Like in living parasite-host systems, trematode-induced malformations are strongly aggregated among hosts, wherein most host individuals harbor very few parasites while a few hosts have many. We interpret trace aggregation to support the assumption that traces are a reliable proxy for trematode parasitism in the fossil record.

Colocolic Intussusception Associated with Octangium sp. (Digenea: Microscaphidiidae) in a Green Sea Turtle Chelonia mydas

Reports of intussusception in sea turtles are generally linked to marine debris ingestion; therefore, only a few cases of the disease are associated with parasitic infestations. The objective of this study was to describe the necropsy findings of the first reported case of colocolic intussusception in a green sea turtle Chelonia mydas, associated with the helminth Octangium sp. A juvenile female green sea turtle, which was registered and rescued by the team from the Cetaceans Project of Costa Branca, State University of Rio Grande do Norte, was examined. The animal died 1 d after being treated and was immediately submitted for necropsy. Our findings indicated that parasitic infestation by Octangium sp. in the green sea turtle caused intussusception and consequently led to the animal's death. Early diagnosis and surgical correction are fundamental for a good prognosis and, consequently, for successful rehabilitation of marine species.

Hemiuroidean trematodes from freshwater Patagonian fishes: description of a new species, distribution and molecular phylogeny

A new trematode species, Derogenes lacustris Tsuchida, Flores, Viozzi, Rauque et Urabe n. sp. (Derogenidae: Derogeninae), from freshwater fishes is described using morphological and molecular approaches in Argentinean Patagonia. D. lacustris is the most common hemiuroidean species in the Limay River basin and parasitizes almost all the native and introduced Patagonian freshwater fish. This new species could be considered as the unique freshwater species in the genus Derogenes Nicoll, 1910. Another hemiuroidean species, Thometrema patagonica Szidat (Archiev Hydrobiol 51: 542-577, 1956) Lunaschi et Drago 2000 (Derogenidae: Halipeginae), is found from Percichthys trucha (Perciformes) in the Neuquén River basin. Its diagnosis and molecular data are provided by the present study. In the molecular analysis of the Patagonian hemiuroideans, T. patagonica composes a group with halipeginean species in the phylogenetic tree of 28S rDNA sequences, while D. lacustris is not included in the same group. D. lacustris also shows low intraspecific variation in COI sequences regardless of the localities or host species.

Co-occurrence and niche overlap among gill parasites of the white mullet (Mugil curema Valenciennes, 1836) (Osteichthyes: Mugilidae) from the western Atlantic, Brazil

Different groups parasitize the gills of fishes, and the organisms can interact in positive, negative, or neutral ways, depending on parasitic abundance, environmental conditions, and the availability of resources. Here, we studied the distribution of ectoparasites on the gills of the mullet Mugil curema in the Cabedelo port region (Brazil), asking if (1) the gill parasites of M. curema fix on specific host gill arches and/or (2) co-occur in the same gill arches within a host individual; (3) if the abundance of one parasite taxon affects the abundance of another on the same gill arches; and (4) considering distinct major groups, if parasites present patterns of co-occurrence on hosts and gill arches different from the expected at random. We used generalized linear models, generalized linear mixed models, and models with zero inflation to define the microhabitats (arches) with the highest abundances of parasites and null models to analyze the co-occurrences of gill parasite groups. Three taxa of Monogenea (Ligophorus brasiliensis Abdallah, Azevedo & Luque, 2009, Ligophorus sp. 1 and Ligophorus sp. 2) and six species of Copepoda were recorded (Bomolochus nitidus Wilson, 1911; Caligus praetextus Bere, 1936; Ergasilus atafonensis Amado & Rocha, 1997; Ergasilus bahiensis Amado & Rocha, 1997; Ergasilus caraguatatubensis Amado & Rocha, 1997 and Ergasilus lizae Krøyer, 1863). We found that, in general, the gill parasites were more abundant/prevalent on specific arches (I and II) of the hosts, shared such preferences and co-occurred on the gill arches. The presence of one taxon influenced the occurrence of another only in the arches I and II; as a result, the infracommunities were characterized as interactive in the gills of this host species.

Species delimitation of Gyrodactylus (Monogenea: Gyrodactylidae) infecting the southernmost cyprinids (Actinopterygii: Cyprinidae) in the New World

The genus Gyrodactylus von Nordmann, 1832 represents one of the most diverse and widespread taxa within Monogenea, with approximately 500 species described worldwide. Thirty-three species of Gyrodactylus have been recorded in Mexico, and in the last two decades, at least 26 new species have been described mainly from freshwater fish families such as poeciliids, goodeids, profundulids, characids, and cichlids. In this study, we describe two new species of Gyrodactylus infecting freshwater cyprinids based on morphological and molecular characteristics. Gyrodactylus ticuchi n. sp. and Gyrodactylus tobala n. sp. were recovered from Notropis moralesi de Buen and N. imeldae Cortés, respectively, captured in five localities from the State of Oaxaca, Mexico. The new species differ slightly from their congeners in the morphology of the haptoral hard parts and the male copulatory organ. Sequences of the Internal Transcribed Spacers rDNA (ITS1-5.8S-ITS2), cytochrome oxidase subunit I (cox1), and the D2 + D3 domains of the large subunit (28S rDNA) were obtained from multiple specimens and analyzed using Maximum Likelihood (ML) and Bayesian Inference (BI). Phylogenetic hypotheses using ITS rDNA, cox1, and 28S rDNA genes recovered two new species of Gyrodactylus from N. moralesi and N. imeldae; we briefly discuss their phylogenetic relationship with other congeners. These gyrodactylids represent the first species described in species of Notropis from southern Mexico, the cyprinids exhibiting the southernmost distribution in the New World.

Larval Gnathostomes and Zoonotic Trematode Metacercariae in Fish from a Local Market in Yangon City, Myanmar

A survey was performed to investigate the infection status of zoonotic helminth larvae in fish from a local market of North Dagon District in Yangon City, Myanmar. A total of 486 fish in 13 species were collected 8 times from December 2015 to December 2019. All fish were transported under ice to a laboratory in Korea and examined for helminth larvae using artificial digestion method. Larval gnathostomes and metacercariae of more than 8 zoonotic trematode species, i.e., Opisthorchis viverrini, Haplorchis taichui, H. pumilio, H. yokogawai, Centrocestus spp., Stellantchasmus falcatus, Pygidiopsis cambodiensis, and Procerovum sp., were detected. Larval gnathostomes were found in 58 (16.0%) out of 362 fish of 6 species, with mean intensity of 2.8 per fish infected. Metacercariae of O. viverrini were detected in 10 (2.9%) out of 349 fish of 5 species, with mean intensity of 16.9 per fish infected. Metacercarial prevalences of 4 intestinal flukes, H. taichui, H. pumilio, H. yokogawai, and Centrocestus spp., were 16.8%, 26.0%, 12.5%, and 15.0% in the positive fish species, respectively, and mean metacercarial intensity was 63.3, 26.8, 86.2, and 8.7 per fish infected. Metacercariae of S. falcatus and P. cambodiensis were detected only from the mullet, Chelon macrolepis. Metacercariae of Procerovum sp. were found in Channa striata and Anabas testudineus. Collectively, it was confirmed that the fish were infected with gnathostome larvae and metacercariae of O. viverrini and intestinal flukes in Yangon City, Myanmar.

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.

Morphological and molecular characterization of larval digenean trematodes (Parvatrema: Gymnophallidae) and their pathological effects on the clam Leukoma thaca (=Protothaca thaca) (Bivalvia:Veneridae) (Molina, 1782) from northern Chile

Trematodes are one of the largest taxa of mollusk parasites. The clam Leukoma thaca is an economically exploited bivalve found along the south-eastern Pacific coast of Peru and Chile. This bivalve is parasitized by various unidentified larval stages of digeneans in the mantle, gonads and digestive gland. The aims of this study were to determine and describe the different larval stages of the digeneans based on morphological characteristics, to identify them at the species level by performing molecular analyses, and to evaluate pathologies associated with the parasites of this clam. Individuals of L. thaca were collected in San Jorge Bay (23°S), Chile, between November 2018 and February 2019. Morphological description was carried out using in vivo and fixed specimens, and analyses including histological and scanning electron microscopy were performed. Individuals were also isolated for molecular analysis using nuclear ribosomal internal transcribed spacer 1 (ITS1), including partial subunit 18S rDNA (18S) and small subunit 5.8S gene (5.8S). Morphological characteristics indicated that the metacercaria larval stage belongs to the family Gymnophallidae, genus Parvatrema, which was supported by molecular analysis. Molecular results revealed that metacercaria, sporocysts and cercaria stages found in this clam belong to the same species of Parvatrema (genetic distance 0%), evidencing that this species uses L. thaca as the first and second intermediate host. Pathologies examined in the host were similar in nature to those reported in other gymnophallids in bivalves, but high prevalence of cercariae (20%) in gonads suggested an important castrator effect on the host.

Helminth diversity in Pimelodus blochii Valenciennes, 1840 (Osteichthyes: Pimelodidae) in two Amazon Rivers

Structure of the helminth community and analyses of helminth population parameters of Pimelodus blochii collected in the Xapuri River in comparison with those in the Acre River were evaluated. Eight adult helminth species were found parasitizing P. blochii in the Acre River: the nematodes Orientatractis moraveci, Rondonia rondoni, Philometroides acreanensis, Cucullanus (Cucculanus) pinai pinai, Procamallanus (Spirocamallanus) pimelodus, Rhadochona acuminata, and Brasilnema sp., and the trematode Dadaytrema oxycephala. For Xapuri’s fishes, nine helminth species were found: the nematodes O. moraveci, R. rondoni, C. (C.) pinai pinai, Procamallanus (Spirocamallanus) rarus, P. (S.) pimelodus, R. acuminata, Brasilnema sp., and Cystidicolidae gen. sp., and the trematode D. oxycephala. Nematode and Acanthocephala larvae were also reported. Helminth abundance, prevalence, and diversity were influenced by seasonality and locality (river). The helminth parasites from Acre’s fishes formed a subset of the helminth community of the Xapuri’s. The results indicate an influence of the environmental characteristics of the rivers on the helminth community structure and diversity. This is the first study of the parasite community of P. blochii in the Xapuri River. The paretheses of (Spirocamallanus) and (S.) should not be in italics all along the text and tables.

[Genetic analysis of mitochondrial pcox1 and ribosomal 18S rRNA genes in Eurytrema pancreaticum isolates from goats in Huaihua City, Hunan Province]

OBJECTIVE

To investigate the genetic variation of Eurytrema pancreaticum isolated from goats in Huaihua City, Hunan Province.

METHODS

The partial sequence of mitochondrial cytochrome I (pcox1) and ribosomal 18S rRNA genes were amplified using a PCR assay in E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and the PCR amplification products were sequenced. Then, the gene sequences were subjected to genetic variation and phylogenetic analyses.

RESULTS

The sequences of the pcox1 and 18S rRNA genes were 430 bp and 1 857 bp in length in 18 E. pancreaticum isolates from goats in Huaihua City, Hunan Province, and there were 14 and 35 variation sites in pcox1 and 18S rRNA gene sequences, with intra-species genetic variations of 0 to 1.4% and 0 to 0.8%, respectively. The sequences of pcox1 and 18S rRNA genes had 99.0% to 99.8% and 99.5% to 99.8% homologies with those from E. pancreaticum Chinese strain recorded in the GenBank database. Consistent phylogenetic analysis results were found based on pcox1 and 18S rRNA genes. The 18 E. pancreaticum isolates from goats in Huaihua City were clustered into a clade with the known E. pancreaticum isolates registered in GenBank, and the clade with these 18 E. pancreaticum isolates was close to the clades with Eurytrema species and far from the clades with other trematodes.

CONCLUSIONS

The E. pancreaticum isolates from goats have a low genetic variation in Huaihua City, Hunan Province. Mitochondrial pcox1 and ribosomal 18S rRNA genes may serve as molecular markers for the studies on the genetic variation in goat-derived E. pancreaticum.

Fish-borne trematode metacercariae detected in fish commonly used for raw consumption in Ninh Binh Province, Vietnam

Raw or undercooked fish dishes are the major sources of human infection of fishborne trematodes (FBT) and the situation of metacercarial infection in fish greatly affect the prevalence in humans, especially those fish that are commonly used for raw consumption. To investigate the situation of infection with metacercaria of FBT in fish often used to prepare raw fish dishes by local people to assess the risk of infection to humans in Ninh Binh province, Vietnam. 345 fish belonging to five species of freshwater and one species of brackish water fish were collected from fishermen or small-scale fish dealers in Kim Son and Yen Khanh districts, Ninh Binh province between May 2017 and May 2018. Metacercaria of FBT was discovered by pepsin and hydrochloric acid digestion techniques and identified by the morphological and molecular analysis. Among examined fish, 44.06% infected with FBT metacercaria and the highest prevalence was in Cyprinus carpio (86.54%), Ctenopharyngodon idellus (78.43%) and Hypophthalmichthys molitrix (66.67%) while Konosirus punctatus - the brackish water fish - were free from infection. Three species of FBT were found; namely Haplorchis pumilio (accounting for 99.84% of collected metacercariae), Haplorchis taichui and Clonorchis sinensis. The average density was 1.06 metacercariae per gram of freshwater fish and the highest number was of C. idellus (6.38 cysts/gram) followed by Cirrhinus molitorella and C. carpio. Results of the study show the high prevalence of infection of FBT metacercariae among freshwater fish often used to prepare raw fish dishes in Ninh Binh province. These findings suggest the need for greater awareness of the risk from raw fish dishes among public health authorities and people.

Prevalence, intensity and pathology of the nasal parasite Nasicola hogansi in Atlantic bluefin tuna (Thunnus thynnus)

Ectoparasitic flatworms of Nasicola (Monogenoidea: Capsalidae), which infect nasal epithelium of true tunas (Thunnus spp.), are not well studied, nor have their impacts on the host's olfactory organ been evaluated. Infections of Nasicola hogansi on Atlantic bluefin tuna, Thunnus thynnus, were investigated with emphasis on the relationship between infection prevalence, abundance and mean intensity with bluefin tuna size, sex, body condition and capture month, as well as histopathological effects. Commercially caught Atlantic bluefin tuna (n = 161, 185-305 cm curved fork length) from the Gulf of Maine were sampled during June through August 2009 for infections by N. hogansi. A total of 247 specimens of N. hogansi were collected, with a prevalence of 45.3%, mean abundance of 1.57 (CI: 1.21-2.03) and mean intensity of 3.45 (CI: 2.91-4.22). Neither fish sex nor landing month had a significant effect on parasite parameters. Larger and better-conditioned Atlantic bluefin tuna had a higher mean intensity of infection. Pathology associated with infection by N. hogansi included extensive necrosis, sloughing of the nasal epithelium and associated inflammation of underlying connective tissues. Further epidemiological and pathological study of this host-parasite system is warranted since impaired olfaction, if present, could adversely affect spawning and migration of this top ocean predator.

First Report of Clinostomum complanatum (Trematoda: Digenea) in European Perch (Perca fluviatilis) from an Italian Subalpine Lake: A Risk for Public Health?

Clinostomum complanatum, a digenean trematode of the Clinostomidae family, is a fish-borne zoonotic parasite responsible for Halzoun syndrome in humans and is transmitted through the consumption of raw or undercooked freshwater fish. Of the total of 112 specimens of European perch (Perca fluviatilis) sampled from a subalpine lake (Lake Endine) in North Italy in 2019, 21 (18.75%) tested positive for encysted metacercariae in the fillet. This study reports the first isolation of C. complanatum in P. fluviatilis and highlights the possible zoonotic risk for consumers, since P. fluviatilis is a food fish used in the traditional local cuisine.

Dactylogyridae (Monogenoidea, Polyonchoinea) from the gills of Auchenipterus nuchalis (Siluriformes, Auchenipteridae) from the Tocantins River, Brazil

Two species of Cosmetocleithrum Kritsky, Thatcher & Boeger, 1986 (both new) and two species of Demidospermus Suriano, 1983 (one new) are reported from the gills of the catfish Auchenipterus nuchalis, popularly known as "mapará", from the Tocantins River and tributaries, North Region of Brazil. Cosmetocleithrum berecae n. sp. differs from all other species presently known in the genus by the morphology of the anchors presenting an elongate shaft and short recurved point, a coiled male copulatory organ (MCO) with three rings, and an elongate slender accessory piece with a bifurcated distal end. Cosmetocleithrum nunani n. sp. differs from its congeners by the combination of the following features: (1) Ventral and dorsal anchors with moderately long curved shaft and short point; (2) Hooks with poorly developed thumb; (3) Hook pairs 5 and 6 similar to each other, but morphologically distinct from remaining hook pairs; and (4) MCO coiled, with approximately 1.5 rings. Demidospermus tocantinensis n. sp. is easily distinguished from other species of the genus by presenting an inverted-G-shaped MCO with a median knee-like expansion. Demidospermus osteomystax Tavernari, Takemoto, Lacerda & Pavanelli, 2010 is redescribed based on paratypes and specimens from the gills of A. nuchalis from the Tocantins River, a new host and locality records for this species. The monotypic Paracosmetocleithrum Acosta, Scholz, Blasco-Costa, Alves & Silva, 2017, the only other Neotropical genus reported in siluriforms besides Cosmetocleithrum with species presenting two ribbon-like projections on the posterior margin of the dorsal bar, is considered a junior subjective synonym of Cosmetocleithrum.

Parasitism by Clinostomum marginatum (Clinostomidae) in neotropical electric fish (Gymnotiformes) in the Brazilian Amazon

Gymnotiformes are currently recognized as electric fish, the vast majority of which emit low power electrical discharges. Clinostomum trematodes have been the subject of numerous investigations in several host species due to the ability of metacercariae of this genus to infect the muscles, fins and internal organs of fish. The present study aimed to record, for the first time, the occurrence of parasitism by Clinostomum marginatum in Gymnotiformes from the natural environments of two tributaries of the Amazon River in the Brazilian Amazon. Two specimens of Gymnotus coropinae, ten specimens of Brachyhypopomus brevirostris, two specimens of Gymnorhamphycthys petiti and one specimen of Microsternarchus bilineatus were captured. Infection with C. marginatum was identified in the form of 12 encysted metacercariae in the epidermis, with a prevalence of 0.1%, a mean infection intensity of 12/fish and an average abundance of 1.2. This is the first record of parasitism by the C. marginatum in South American Gymnotiformes of the B. brevirostris species.

Characterisation of gastrointestinal helminths and their impact in commercial small-scale chicken flocks in the Mekong Delta of Vietnam

Commercial small-scale chicken farms managed as all-in-all-out but operating with low standards of hygiene/biosecurity are increasingly common in Vietnam. These conditions facilitate the transmission of gastrointestinal helminths. However, there are no published data on helminths in these systems. We aimed (1) to determine the prevalence/burden of gastrointestinal helminths in small-scale commercial flocks in the Mekong Delta region and (2) to investigate the association between worm burdens and birds' weight and disease status. Randomly selected chickens (n = 120) from 'normal' flocks were investigated at the end of their production cycle (~ 18 weeks), as well as 90 chickens from 'diseased' flocks with signs of respiratory and/or severe disease. The gastrointestinal tract of chickens was dissected and all visible helminths were identified and counted. A total of 54.2% and 54.4% normal and diseased chickens contained helminths. Among colonised birds, the diseased ones harboured a higher mass of helminth worms than normal (healthy) birds (3.8 ± SD 8.6 g vs. 1.9 ± SD 6.3 g, respectively). Eight species were identified, including nematodes (Ascaridia galli, Cheilospirura hamulosa and Heterakis gallinarum), cestodes (Hymenolepis, Raillietina cesticillus, Raillietina echinobothrida, Raillietina tetragona,) and one trematode (Echinostomatidae). Heterakis gallinarum was the most prevalent helminth (43.3% and 42.2% in normal and sick chickens, respectively), followed by A. galli (26.7% and 41.1%). Colonised chickens weighed 101.5 g less than non-colonised birds. Colonisation was higher during the rainy months (May-November) for both H. gallinarum and A. galli. Anthelminthic usage was not associated with reduced helminth burdens. We recommend upgrading cleaning and disinfection and limiting access to ranging areas to control helminths in small-scale chicken flocks.

Two New Species of Haematoloechus (Digenea: Plagiorchidae) Parasitizing Rana brownorum (Amphibia: Ranidae) from Southeast Mexico

In an ongoing investigation on the helminths of amphibians in southeastern Mexico, specimens of 2 undescribed species of Haematoloechus were collected from Rana brownorum. Haematoloechus ceciliae n. sp. is morphologically most similar to Haematoloechus meridionalis, but differs in the shape of the oral sucker, in the nature of the acetabulum, and in the distribution of the glandular cells in the pharyngeal region; Haematoloechus celestunensis n. sp. closely resembles Haematoloechus floedae, but differs in the form and size of the testes and measurements of acetabulum. COI and 28S DNA sequences of both new species show high divergence compared to other species of the genus. In the phylogenetic trees, H. ceciliae appears most closely related to Haematoloechus danbrooksi and H. celestunensis to Haematoloechus veracruzanus.

Mini-FLOTAC as an alternative, non-invasive diagnostic tool for Schistosoma mansoni and other trematode infections in wildlife reservoirs

BACKGROUND

Schistosomiasis and food-borne trematodiases are not only of major public health concern, but can also have profound implications for livestock production and wildlife conservation. The zoonotic, multi-host nature of many digenean trematodes is a significant challenge for disease control programmes in endemic areas. However, our understanding of the epidemiological role that animal reservoirs, particularly wild hosts, may play in the transmission of zoonotic trematodiases suffers a dearth of information, with few, if any, standardised, reliable diagnostic tests available. We combined qualitative and quantitative data derived from post-mortem examinations, coprological analyses using the Mini-FLOTAC technique, and molecular tools to assess parasite community composition and the validity of non-invasive methods to detect trematode infections in 89 wild Hubert's multimammate mice (Mastomys huberti) from northern Senegal.

RESULTS

Parasites isolated at post-mortem examination were identified as Plagiorchis sp., Anchitrema sp., Echinostoma caproni, Schistosoma mansoni, and a hybrid between Schistosoma haematobium and Schistosoma bovis. The reports of E. caproni and Anchitrema sp. represent the first molecularly confirmed identifications for these trematodes in definitive hosts of sub-Saharan Africa. Comparison of prevalence estimates derived from parasitological analysis at post-mortem examination and Mini-FLOTAC analysis showed non-significant differences indicating comparable results between the two techniques (P = 1.00 for S. mansoni; P = 0.85 for E. caproni; P = 0.83 for Plagiorchis sp.). A Bayesian model, applied to estimate the sensitivities of the two tests for the diagnosis of Schistosoma infections, indicated similar median posterior probabilities of 83.1% for Mini-FLOTAC technique and 82.9% for post-mortem examination (95% Bayesian credible intervals of 64.0-94.6% and 63.7-94.7%, respectively).

CONCLUSIONS

Our results showed that the Mini-FLOTAC could be applied as an alternative diagnostic technique for the detection of the zoonotic S. mansoni and other trematodes in rodent reservoirs. The implementation of non-invasive diagnostics in wildlife would offer numerous advantages over lethal sampling methodologies, with potential impact on control strategies of zoonotic helminthiases in endemic areas of sub-Saharan Africa and on fostering a framework of animal use reduction in scientific practice.

Brachylaima lignieuhadrae n. sp. (Trematoda: Brachylaimidae) from land snails of the genus Euhadra in Japan

Land snails of the genus Euhadra (Gastropoda: Bradybaenidae) are indigenous to the Japanese Archipelago. The larvae of an unknown species, tentatively named as Brachylaima sp. B (Trematoda: Brachylaimidae), have been found from Euhadra brandtii sapporo in Hokkaido, the northernmost island of Japan. In this study, a large-scale snail survey covering a wide area of Japan was conducted to confirm the larval parasite from members of Euhadra and related genera. Sporocysts with cercariae were found only from Eu. brandtii sapporo in Hokkaido and Euhadra callizona in central Honshu at low prevalence (1.0-9.6%). The metacercariae were detected widely from 6 species of Euhadra and the related genera at high prevalence (7.1-100%). A molecular identification by DNA barcoding demonstrated almost all of the larvae to be Brachylaima sp. B. Adult worms experimentally raised from the metacercariae were morphologically most similar to Brachylaima ezohelicis in Hokkaido, but could be differentiated by the microstructure of the tegumental surface. We propose Brachylaima lignieuhadrae n. sp. for the unknown species, based on the morphology, DNA profile, host specificity, and geographic distribution. Phylogeography of the new species suggests a possibility that migratory birds serve as the definitive hosts.

Validation of Bifurcohaptor spp. (Monogenoidea: Dactylogyridae) reported from India using molecular methods with inclusion of insilico study: A brief report on its host-specificity

A total of 17 species of the genus Bifurcohaptor Jain, 1958 have been reported from two fish families namely Bagridae Bleeker, 1858 (Mystus vittatus (Bloch, 1794), M. tengara (Hamilton, 1822), M. keletius (Valenciennes, 1840), Hemibagrus nemurus (Valenciennes, 1840), Rita rita (Hamilton, 1822) and Sperata seenghala (Sykes, 1839)) and Sisoridae Bleeker, 1858 (Bagarius bagarius (Hamilton, 1822)). Out of these, only two species viz. B. indicus and B. giganticus are found valid in India, parasitizing gills of Mystus spp. and Bagarius sp. Taxonomic studies suggest, present specimen of B. indicus and B. giganticus, both are morphologically close to species described by Jain (1958), except morphometric variations and posses 7 pairs of marginal hooks instead of 6 pairs. Present manuscript delves with the characterization of B. indicus and B. giganticus reported from India, using molecular techniques. Partial mt COI nucleotide sequence based insilico protein analysis and partial 28S and ITS-1 rDNA based phylogenetic analysis, estimated by Neighbour-joining (NJ) and Minimum Evolution (ME) methods revealed that the species of the genus Bifurcohaptor are genetically distinct and valid. The grouping of Bifurcohaptor spp. with other representatives of family Dactylogyridae supports morphology based placement into family Dactylogyridae. Present and previous host-parasite information suggests both Bifurcohaptor spp. are species specialist however, the genus Bifurcohaptor is generalist at generic level.

A Philophthalmid Eyefluke from a Human in Japan

Philophthalmid eyeflukes are cosmopolitan parasites of birds and occasionally of mammals, including humans. A gravid adult of Philophthalmus sp. was found from the bulbar conjunctiva of a 64-yr-old woman in Japan, who was diagnosed with acute conjunctivitis. The parasite was morphologically most similar to Philophthalmus hegeneri, but distinctive in lacking an esophagus and in having clearly lobed testes. The DNA sequence analysis of genes for nuclear 28S ribosomal RNA and mitochondrial cytochrome c oxidase subunit 1 supported the identification at generic level. The morphological and molecular analyses strongly suggest that the eyefluke from a human in Japan should be treated as an undescribed species of Philophthalmus. The occurrence of human philophthalmosis is very rare. As far as we know, a total of 11 human cases have been reported worldwide to date.

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.

Parasite fauna of wild Antillean manatees (Trichechus manatus manatus) of the Andean Region, Colombia

BACKGROUND

Antillean manatees (Trichechus manatus manatus) are large herbivorous aquatic mammals living in limited areas of South, Central and North America. As with other aquatic mammals, Antillean manatees can be infected by a variety of protozoan and metazoan parasites, some of them with zoonotic potential, which affect not only their welfare but also population health status. Therefore, we conducted the first epidemiological survey in Colombian free-ranging Antillean manatees to estimate their actual gastrointestinal parasite status.

RESULTS

In total, 69 faecal samples were collected from free-ranging individual manatees during ecology field studies in the rivers Carare and San Juan and in two associated wetlands in the Andean region of Colombia. Parasite diversity encompassed six different endoparasite species. The highest prevalence was found for protozoan infections with Eimeria nodulosa (47.8%) and Eimeria manatus-like species (type A, B; 43.4%), followed by Entamoeba sp. (14.49%) and Giardia sp. (1.4%) infections. In addition, infections with the trematode Chiorchis fabaceus were detected at a high prevalence (33.3%). Molecular characterization of sirenian Eimeria species led to the distinction of three species, E. nodulosa and two E. manatus-like species (type A, B). Phylogenetic analyses indicated a host-specific adaptation of sirenian Eimeria species as previously reported for Eimeria species from other mammalian hosts.

CONCLUSIONS

This study provides the first record of Antillean manatee infection with Giardia and Entamoeba species in Colombia, representing two important anthropozoonotic parasite genera. This survey should serve as a baseline investigation for future monitoring on parasitic zoonoses in this mammal and encourage for investigations on their impact on both public health and wild manatee welfare.