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Nectonema, the only horsehair worm (Nematomorpha) genus found in marine environments, was previously known to be parasitic only in decapod crustaceans. We report Nectonema sp. as the first record of a marine nematomorph parasitic in isopod crustaceans. This is also the third record of marine nematomorphs from the North Pacific. Six infected isopods (Natatolana japonensis) collected from 1425 m of depth in the Sea of Japan each contained one to seven (mean 2.33) nematomorphs in the body cavity in the pereon. There was no correlation between the host body length and number of parasites. For Nectonema sp., we describe and illustrate morphological features of the parasitic juvenile stage and present nucleotide sequences for the cytochrome c oxidase subunit I gene (COI or cox1; 451 nt), 18S rRNA gene (1777 nt), and region spanning the internal transcribed spacer 1 (ITS1) and the 28S rRNA gene including the 5.8S rRNA gene and ITS2 (1218 nt in total). In an 18S maximum-likelihood tree that included 24 nematomorph species, Nectonema sp. grouped with N. agile from the northwestern Atlantic; the 18S gene from these two taxa was divergent by 11.8% K2P distance, suggesting that they are different species. Nectonema species may have a broader range of host groups than previously suspected, but may have been previously misidentified as nematode parasites., 謎多き海のハリガネムシの予想外の宿主を発見. 京都大学プレスリリース. 2021-06-29.

The aim of this study was to evaluate the sensitivity of four coprodiagnostic techniques to quantitatively determine the presence of Toxocara canis eggs in fresh canine stool samples. For this, eggs were extracted from the uterus of adult female T. canis obtained from canine puppies. Eight concentrations of eggs were used (10, 50, 75, 100, 250, 500, 750 and 1 000 eggs per gram of faeces - hpg), being considered as the gold standard to determine the degree of precision of the Kato-Katz, McMaster, Improved Modified McMaster and Faust techniques. Three repetitions were used per technique and per concentration. The sensitivity of each test was performed by arithmetic calculation and ROC curve (95% CI), comparing them with the gold standard by means of a nonparametric test of the Wilcoxon signed ranges (p, El estudio tuvo como objetivo evaluar la sensibilidad de técnicas coprodiagnósticas para determinar cuantitativamente la presencia de huevos de Toxocara canis en muestras de heces frescas de caninos. Para ello, se extrajeron huevos del útero de hembras adultas de T. canis obtenidas de cachorros caninos. Se utilizaron ocho concentraciones de huevos (10, 50, 75, 100, 250, 500, 750 y 1 000 huevos por gramo de materia fecal – hpg), siendo considerados como el gold standard para determinar el grado de precisión de las técnicas Kato-Katz, McMaster, McMaster modificado mejorado y Faust. Se utilizaron tres repeticiones por técnica y por concentración. La sensibilidad de cada prueba se realizó mediante el cálculo aritmético y curva ROC (IC95%), comparándolas con el gold standard mediante una prueba no paramétrica de los rangos con signo de Wilcoxon (p

International audience; Background: Long-read sequencing is increasingly being used to determine eukaryotic genomes. We used nanopore technology to generate chromosome-level assemblies for 3 different strains of Drechmeria coniospora, a nematophagous fungus used extensively in the study of innate immunity in Caenorhabditis elegans. Results: One natural geographical isolate demonstrated high stability over decades, whereas a second isolate not only had a profoundly altered genome structure but exhibited extensive instability. We conducted an in-depth analysis of sequence errors within the 3 genomes and established that even with state-of-the-art tools, nanopore methods alone are insufficient to generate eukaryotic genome sequences of sufficient accuracy to merit inclusion in public databases. Conclusions: Although nanopore long-read sequencing is not accurate enough to produce publishable eukaryotic genomes, in our case, it has revealed new information about genome plasticity in D. coniospora and provided a backbone that will permit future detailed study to characterize gene evolution in this important model fungal pathogen.

A new nematode species, Rhabdias kiri sp. nov., which is a lung parasite in a microhylid frog Microhyla okinavensis Stejneger, 1901 from Ishigakijima island in the Yaeyama Islands of Ryukyu Archipelago, Japan is described and illustrated. This new species differs from other congeners inhabiting East Asia and the Russian Far East in its features: i.e., shorter body length, slender body shape, narrower and shallower buccal capsule, shorter head diameter and cuticular inflation less prominent in the anterior and middle parts of the body. This is the first record of a frog parasite in Rhabdias from the Yaeyama Islands. Partial sequences of mitochondrial cytochrome c oxidase subunit I and 12S rDNA genes were provided as DNA barcodes for the new species.

A new nematode species that is lung parasitic to a bufonid toad, Rhabdias kafunata sp. nov., is described and illustrated from Miyakojima island, Okinawa Prefecture, Japan. Although the new species was previously identified as R. incerta Wilkie, 1930, it is clearly distinguishable from that species by the characteristics of body proportion, buccal capsule, and esophagus. Additionally, the new species differs from other congeners inhabiting East Asia and the Russian Far East in the following features: longer body length, cup-like buccal capsule, longer esophagus length, presence of thickened anterior muscular part in esophagus, cuticular inflation less prominent in region posterior to small cephalic cuticular inflation, middle part of body and tail tip, and tail long and tapering. Partial sequences of mitochondrial cytochrome c oxidase subunit I and 12S rDNA genes were provided as DNA barcodes for the new species.

Host–parasite coevolution stems from reciprocal selection on host resistance and parasite infectivity, and can generate some of the strongest selective pressures known in nature. It is widely seen as a major driver of diversification, the most extreme case being parallel speciation in hosts and their associated parasites. Here, we report on endoparasitic nematodes, most likely members of the mermithid family, infecting different Timema stick insect species throughout California. The nematodes develop in the hemolymph of their insect host and kill it upon emergence, completely impeding host reproduction. Given the direct exposure of the endoparasites to the host's immune system in the hemolymph, and the consequences of infection on host fitness, we predicted that divergence among hosts may drive parallel divergence in the endoparasites. Our phylogenetic analyses suggested the presence of two differentiated endoparasite lineages. However, independently of whether the two lineages were considered separately or jointly, we found a complete lack of codivergence between the endoparasitic nematodes and their hosts in spite of extensive genetic variation among hosts and among parasites. Instead, there was strong isolation by distance among the endoparasitic nematodes, indicating that geography plays a more important role than host‐related adaptations in driving parasite diversification in this system. The accumulating evidence for lack of codiversification between parasites and their hosts at macroevolutionary scales contrasts with the overwhelming evidence for coevolution within populations, and calls for studies linking micro‐ versus macroevolutionary dynamics in host–parasite interactions.

Diplotriaena delirae Pinto & Noronha, 1970 is known to parasitize Pitangus sulphuratus (Linnaeus, 1766) in Peru and in the Midwestern and Southeastern regions of Brazil. Here, specimens of P. sulphuratus were collected in the southern state of Rio Grande do Sul, Brazil, and necropsied. Nematodes (n = 6) found in these specimens were identified as D. delirae based on their morphological traits. This is the first report of D. delirae from southern Brazil, expanding the knowledge of the helminth fauna of P. sulphuratus in the Neotropical region.

The present study describes the occurrence of various gastrointestinal helminths and liver flukes in goats from post mortem examinations performed between 2010 and 2011. Forty five adult goats were euthanized necropsy examination and for identification of adult gastrointestinal helminths and liver flukes. Eleven animals (24.44 %) were found to be infected with one or more species of gastrointestinal helminth. Haemonchus contortus emerged as the most prevalent species (15.5 %), with Moniezia expansa and Fasciola gigantica also being common (11.11 % and 4.4 %, respectively). Additionally, Haemonchus longistipes, Cysticercus tenuicollis, and Paramphistomum microbothrium were present at low infection rates (2.2 %). Mixed infections were similarly most prevalent. Haemonchus longistipes; the most pathogenic Strongyle nematode of camels was reported for the first time infecting goats in Egypt. The present study indicates that abattoir surveys would reveal the prevalence of various species of problematic helminths, and thus appropriate measures can be adopted to control the respective worms.

Intestinal strongyles are the most problematic endoparasites of equids as a result of their wide distribution and the spread of resistant isolates throughout the world. While abundant literature can be found on the extent of anthelmintic resistance across continents, empirical knowledge about associated risk factors is missing. This study brought together results from anthelmintic efficacy testing and risk factor analysis to provide evidence-based guidelines in the field. It involved 688 horses from 39 French horse farms and riding schools to both estimate Faecal Egg Count Reduction (FECR) after anthelmintic treatment and to interview farm and riding school managers about their practices. Risk factors associated with reduced anthelmintic efficacy in equine strongyles were estimated across drugs using a marginal modelling approach. Results demonstrated ivermectin efficacy (96.3% ± 14.5% FECR), the inefficacy of fenbendazole (42.8% ± 33.4% FECR) and an intermediate profile for pyrantel (90.3% ± 19.6% FECR). Risk factor analysis provided support to advocate for FEC-based treatment regimens combined with individual anthelmintic dosage and the enforcement of tighter biosecurity around horse introduction. The combination of these measures resulted in a decreased risk of drug resistance (relative risk of 0.57, p = 0.02). Premises falling under this typology also relied more on their veterinarians suggesting practitionners play an important role in the sustainability of anthelmintic usage. Similarly, drug resistance risk was halved in premises with frequent pasture rotation and with stocking rate below five horses/ha (relative risk of 0.53, p