Molecular characterization of a novel Spiruromorpha species in wild Chinese pangolin by mitogenome sequence analysis.

Pangolins are susceptible to a variety of gastrointestinal nematodes due to their burrowing lifestyle and feeding habits, and few parasitic nematodes have been reported. Here, a Chinese pangolin with old wounds on its leg and tail was rescued from the Heyuan City, Guangdong Province. The cox1 and SSU rRNA of the worms from the intestine of the Chinese pangolin had the highest sequence identity of 89.58% and 97.95% to the species in the infraorder Spiruromorpha. The complete mitogenome of the worm was further assembled by next-generation sequencing, with a size of 13,708 bp and a GC content of 25.6%. The worm mitogenome had the highest sequence identity of 78.56% to that of Spirocerca lupi, sharing the same gene arrangement with S. lupi and some species in other families under Spiruromorpha. However, the mitogenome between the worm and S. lupi showed differences in codon usage of PCGs, sequences of NCR, and tRNA secondary structures. Phylogenetic analysis showed that the worm mitogenome was clustered with S. lupi in the family Thelaziidae to form a separate branch. However, it is still difficult to identify the worm in the family Thelaziidae because the species in the family Thelaziidae are confused, specifically S. lupi and Thelazia callipaeda in the family Thelaziidae were separated and grouped with species from other families. Thus, the parasitic nematode from the Chinese pangolin may be a novel species in Spiruromorpha and closely related to S. lupi. This study enriches the data on gastrointestinal nematodes in the Chinese pangolin.

Gastrointestinal helminths of the Australasian harrier (Circus approximans Peale, 1848) in New Zealand, and description of a new species of nematode, Procyrnea fraseri n. sp. (Habronematidae).

The Australasian harrier Circus approximans, a native of Australia, New Zealand and the South Pacific, is an opportunistic hunter of small prey, although a large part of its diet consists of carrion, mainly from roadkill. Besides a record of a single, unnamed species of capillariid nematode there have been no investigations into the parasites of Australasian harriers in New Zealand. In this study, a helminthological survey of sixty-five deceased harriers from southern New Zealand uncovered a gastrointestinal helminth fauna consisting of six parasite species. Porrocaecum circinum (Nematoda) was previously described only from fragmented females, and a redescription is presented here. Procyrnea fraseri n. sp. (Nematoda) is described, and distinguished from its congeners by its slender body shape and shorter spicules. Strigea falconis (Trematoda) is reported for the first time in New Zealand. Cladotaenia anomalis (Cestoda) and Polymorphus circi (Acanthocephala) were previously described as new species elsewhere. An unnamed species of capillariid appears to be mainly confined to North Island and is rare in South Island. Prevalence and intensity metrics are given, and DNA sequences provided to accompany new re/descriptions. Potential intermediate hosts are discussed, and the origins of the helminths and their potential for pathogenicity are considered.

Complete mitochondrial genome of Metathelazia capsulata (Pneumospiruridae) and comparison with other Spiruromorpha species.

Metathelazia capsulata (family Pneumospiruridae) is a lungworm parasitizing the bronchi and bronchioles, described in four species of wild carnivores. Very little molecular data are available on this nematode and none on other species of the Pneumospiruridae family. In this work, we describe for the first time the complete mitogenome (mitochondrial genome) of M. capsulata, being the first described of the family Pneumospiruridae. The mitogenome of M. capsulata has 13,659 bp in length, an A + T content of 79.2%. The mitogenome included 12 protein-coding genes (PCGs) (lacking the atp8 gene), 22 tRNA genes, 2 rRNA genes (all the genes are coded by the heavy strand), and an AT-rich region. The PCGs varied in size (232 bp-1645 bp). Only the tRNA-Trp has the standard cloverleaf secondary structure, while the other 21 do not. The AT-rich region, with a 90.5% A + T content and a length of 389 bp, is located between the cox3 and tRNA-Ala genes. Comparison with the mitogenomes of 29 species of Spiruromorpha infraorder, belonging to different families, demonstrates that M. capsulata mitogenome shared the common characteristics of most of them. The phylogeny constructions yielded phylogenies that were in agreement with the obtained previously by using sequences and gene order data of mitogenomes.

Morphological and molecular characterization of larval Echinocephalus sp. (Spirurida: Gnathostomatidae), a parasite of the greater lizard fish (Saurida undosquamis) and red porgy or common seabream (Pagrus pagrus).

Larvae of an unidentified Echinocephalus species were obtained from two fish species: red porgy or common seabream (Pagrus pagrus) and greater lizard fish (Saurida undosquamis) from the Red Sea. The prevalence of Echinocephalus sp. larvae in P. pagrus was 4.92% and 4.98% in S. undosquamis. The length, width, cephalic bulb, and spine shape and pattern of the larvae resembled Echinocephalus overstreeti. SSU gene sequences of larvae from P. pagrus and S. undosquamis were identical. Comparison of the SSU sequence to those available in GenBank showed that the larvae from P. pagrus and S. undosquamis are diagnosably distinct. Based on sequence similarity and published phylogenetic analysis, these larvae are most similar to an unknown species of Echinocephalus from an Australian sea snake (Hydrophis peronii). Despite morphological similarities of the Red Sea larvae to E. overstreeti, the SSU sequence differences show that they are not the same species.

Morphology and genetic characterization of Physaloptera sibirica Petrow & Gorbunov, 1931 (Spirurida: Physalopteridae), from the hog-badger Arctonyx collaris Cuvier (Carnivora: Mustelidae), with molecular phylogeny of Physalopteridae.

BACKGROUND: Nematodes of the family Physalopteridae (Spirurida: Physalopteroidea) commonly parasitize the alimentary canal of all major vertebrate groups. However, many physalopterid species are not adequately described, especially regarding the detailed morphology of the cephalic end. The current genetic database for Physaloptera species is still very limited, which seriously hampers molecular-based species identification. Additionally, the systematic status of some genera and the evolutionary relationships of the subfamilies in the Physalopteridae remain under debate. METHODS: New morphological data for Physaloptera sibirica was gathered using light and scanning electron microscopy based on newly collected specimens from the hog badger Arctonyx collaris Cuvier (Carnivora: Mustelidae) in China. Six different genetic markers, including nuclear small ribosomal DNA (18S), large ribosomal DNA (28S) and internal transcribed spacer (ITS), mitochondrial cytochrome c oxidase subunit 1 (cox1) and subunit 2 (cox2), and the 12S small subunit ribosomal RNA gene of P. sibirica were sequenced and analyzed for the first time to our knowledge. Additionally, to construct a basic molecular phylogenetic framework for the Physalopteridae, phylogenetic analyses were performed based on the cox1 and 18S + cox1 genes using maximum likelihood (ML) and Bayesian inference (BI) methods. RESULTS: Scanning electron microscopy (SEM) observation displayed the details of the cephalic structures, deirids, excretory pore, caudal papillae, vulva, phasmids and egg of P. sibirica for the first time to our knowledge. Pairwise comparison of the sequences obtained for P. sibirica did not reveal intraspecific divergence regarding the 18S, 28S, cox1 and 12S genetic markers and a low level of divergence in the ITS (0.16%) and cox2 (2.39%) regions. Maximum likelihood and Bayesian inference analyses showed that the representatives of Physalopteridae formed two major clades (species of Physalopterinae + Thubunaeinae parasitic in terrestrial vertebrates and Proleptinae only occurring in marine or freshwater fishes). Turgida turgida was found nested among representatives of Physaloptera. Physaloptera sibirica clustered together with P. rara. Physalopteroides sp. (Thubunaeinae) formed a sister relationship to the physalopterine Abbreviata caucasica. CONCLUSIONS: Physaloptera sibirica was redescribed, which is the fourth nematode parasite reported from the hog badger A. collaris, and A. collaris represents a new host for P. sibirica. The phylogenetic results challenged the validity of the subfamily Thubunaeinae and of the genus Turgida and supported dividing the family Physalopteridae into two subfamilies, Physalopterinae and Proleptinae. However, we do not make any immediate systematic changes in the Physalopteridae, because a more rigorous study with broader representation of the Physalopteridae is required. These present findings contribute to morphologically identifying P. sibirica more accurately and provide new insights into the systematics of the Physalopteridae.

Pathological findings associated with Dipetalonema spp. (Spirurida, Onchocercidae) infection in two species of Neotropical monkeys from Brazil.

Among vector-borne helminths, filarioids of the genus Dipetalonema (Spirurida: Onchocercidae) localize in several tissues and body cavities of several animal species, causing mild to moderate lesions. The pathological findings associated with Dipetalonema spp. infection in Neotropical monkeys from southern Brazil are herein described, along with a fatal case due to filarial polyserositis and entrapment of an intestinal segment. At necropsy, nematodes were observed in abdominal and thoracic cavities, or in the pericardium of 37 (31.3%) out of the 118 individuals examined (i.e., 35 Alouatta guariba clamitans and two Sapajus nigritus). In addition, at histology, 27.0% of positive animals presented microfilarie (inside blood vessels of lung, spleen, liver, and brain) and 8.1% presented adult nematodes in the heart, lung, and liver. In two cases, cross-sections of filarioids were associated with areas of epicardial thickening with intense fibrosis and pyogranulomatous inflammation in the brain, heart, liver, lungs, or spleen. The DNA fragment was amplify using the cox1 gene, sequenced and analyzed to identify the nematode species collected; presence of Wolbachia was assessed in the filarioids using the 16S rRNA gene. At BLAST analysis of the cox1 gene, 10 sequences showed 91.7% nucleotide identity with Dipetalonema gracile, and two with D. gracile (98.5%) and Dipetalonema graciliformis (98.3%). Phylogenetic analyses clustered sequences of the cox1 obtained in this study in two clades corresponding with the host species. Wolbachia sp. endosymbiont was detected in four samples. Data herein reported provide a description of pathological lesions associated with the infection by Dipetalonema spp., suggesting that they may cause disease in Neotropical monkeys. In addition, a better understanding of diversity and biology of Dipetalonema spp. in South America is needed to assess the impact they may cause in native non-human primates from Brazil.

New reports of parasitism by Synhimantus (Dispharynx) nasuta (Rudolphi, 1819) (Nematoda: Acuariidae) in wild birds in Brazil.

The aim of this study was to register the first occurrence of Synhimantus (Dispharynx) nasuta (Nematoda: Acuariidae) in some species of wild birds in Brazil. In addition, the aim was to deepen the knowledge about the morphology of this species through analysis using scanning electron microscopy. Nematodes were collected in wild birds of the species Turdus leucomelas, T. rufiventris, Mimus saturninus, Pitangus sulphuratus, Megascops choliba, Tyto furcata, and Falco sparverius. The morphological and morphometric data observed in the nematodes prove that these parasites are S. (D.) nasuta. This study also provides morphological data from light microscopy and scanning electron microscopy (SEM), as well as the morphometry of this nematode in each host species. Therefore, the current study confirms the first record of this nematode in F. sparverius and T. furcata in South America and, at the same time, these findings expand the host range of this parasite species worldwide, through the first records in M. choliba, M. saturninus, T. leucomelas and T. rufiventris.

Anatomical and molecular characterization of some rhigonematid parasites of millipedes in Nigeria, with new insights into their phylogeny.

Parasitic nematodes of millipedes from Nigeria are molecularly characterized for the first time. During nematode surveys on live giant African millipedes from several localities in Nigeria, 4 species of rhigonematids were identified by application of integrative taxonomical approaches (morpho-anatomy and molecular markers), including Brumptaemilius sp., Gilsonema gabonensis, Obainia pachnephorus, and Rhigonema disparovis. The results of morphometric and molecular analyses of D2-D3 28S, ITS, partial 18S rRNA, and cytochrome oxidase c subunit 1 (COI) gene sequences further characterized the rhigonematid species, and clearly separated them from other related species. Phylogenetic relationships based on 28S and 18S rRNA genes suggest that genera within Ransomnematoidea (Ransomnema, Heth, Carnoya, Brumptaemilius, Cattiena, Insulanema, Gilsonema) and Rhigonematoidea (Rhigonema, Obainia, Xystrognathus, Trachyglossoides, Ichthyocephaloides) clustered rather closer than could be expected in view of their morphological differences. Phylogenetic relationships based on ITS and COI are congruent with those of other ribosomal genes; however, they are not conclusive due to the scarcity of available sequences of these genes for these genera in NCBI.

A redescription of Hedruris moniezi Ibáñez & Córdova, 1976 (Nematoda: Hedruridae), an endoparasite of the Titicaca water frog Telmatobius culeus (Garman, 1876) (Anura: Telmatobiidae), with comments on all other known Hedruris species in Peru.

Hedruris moniezi Ibáñez & Córdova, 1976 (Nematoda: Hedruridae) was described using light and scanning electron microscopy (SEM) based on specimens collected from the stomach of Telmatobius culeus (Anura: Telmatobiidae) in Peru. We observed some characteristics not reported previously, including sessile and pedunculated papillae and amphid on the pseudolabia, bifid deirids, morphology of the retractable chitinous hook, morphology and arrangement of the plates on ventral surface of the posterior end of the males, and arrangement of caudal papillae. Telmatobius culeus represents a new host of H. moniezi. In addition, H. basilichtensis Mateo, 1971 is considered to be a junior synonym of H. oriestae Moniez, 1889. A key to valid species of Hedruris in Peru is provided.

Redescription of Thubunaea schukurovi Annaev, 1973 from Ablepharus chernovi, with notes on the members of Thubunaea (Spirurida: Physalopteridae) from the Palaearctic and Indomalayan realms.

The spirurid nematode Thubunaea schukurovi Annaev, 1973 (Physalopteridae) is redescribed by means of light microscopy and scanning electron microscopy from Ablepharus chernovi collected in Çamliyayla, Turkey. This is the first record of the species from this host and the first record of the genus Thubunaea from Turkey. The taxonomic status of the species of the genus Thubunaea from the Palaeacrtic and Indomalayan realms is reviewed based on their original morphological descriptions; as a result, Thubunaea dessetae Barus & Tenora, 1976, a parasite of Saara hardwickii (Gray) (Agamidae) in Afghanistan, is transferred to the genus Pseudabbreviata as Pseudabbreviata dessetae (Barus & Tenora, 1976) n. comb. Several species described in India, that is, Thubunaea singhi Deshmukh, 1969 and Thubunaea brooki Deshmukh, 1969, both from Hemidactylus brookii Gray (Gekkonidae), and Thubunaea aurangabadensis Deshmukh, 1969 and Thubunaea syedi Deshmukh, 1969, both from Hemidactylus giganteus Stoliczka, are considered members of the genus Physalopteroides; therefore, the following new combinations are proposed: Physalopteroides singhi, Physalopteroides brooki, Physalopteroides aurangabadensis and Physalopteroides syedi. Thubunaea hemidactylae Oshmarin & Demshin, 1972 from Hemidactylus frenatus Duméril & Bibron in Vietnam is considered a member of the genus Physalopteroides as P. hemidactylae (Oshmarin & Demshin, 1972) n. comb.

A new species of Hedruris Nitzsch, 1821 (Nematoda: Hedruridae) parasitic in eel Synbranchus marmoratus Bloch (Synbranchiformes: Synbranchidae) from Argentina, Neotropical Region.

During a parasitological survey, specimens belonging to the genus Hedruris (Nematoda: Hedruridae) were found in the stomach of Synbranchus marmoratus Bloch from the Paraná Guazú River, Paraná River basin (Argentina). Comparative morphological studies with its congeners showed that these nematodes belonged to a new species, herein described as Hedruris anguila sp. nov. The new species can be distinguished from remaining Hedruris species by the pseudolabia size, the morphology and size of spicules, the length of female caudal hook, the shape and size of eggs and the particular morphology of the male tail. Hedruris anguila sp. nov. closely resembles Hedruris bifida Rossin & Timi, 2016 and H. suttonae Brugni & Viozzi, 2010, both also described from fish hosts, in the arrangement of caudal papillae and morphology of eggs, but differ in the size of female hook and spicules, and the number of caudal papillae in males. The main morphological features, host range and geographical distribution of all species in the genus Hedruris species are analyzed and discussed. This is the first report of a representative of the family Hedruridae parasitizing a species of Synbranchidae and the eleventh report of the genus Hedruris for a fish host. The number of valid species of Hedruris described was increased to 26, including the new species; 11 for the Neotropical Region and represent the third species found in fish host from Argentina. Based on morphological analysis, the speciation process probably occurred first in Gondwana and the non-mammillated eggs could be an ancestral morphological character. The diet of Synbranchus marmoratus and values of prevalence and mean intensity could indicate that this host species is a true definitive host for this nematode.

Advancing the knowledge of the nematode Echinocephalus pseudouncinatus (Gnathostomatidae, Spirurida): Morphological and molecular identification, new host, and host specificity in two coexisting pen shells (Bivalvia: Pinnidae).

The life cycle of Echinocephalus pseudouncinatus has not been described in detail to date, as is also the case of other species in the genus. This study contributes to the information available about the life history of the genus, particularly E. pseudouncinatus, by (1) using molecular techniques (small subunit rRNA gene [SSU rRNA] sequences) to identify larvae of this species; (2) describing the most conspicuous morphological characteristics that distinguish the species by scanning electron microscopy; (3) describing histological characteristics of the internal anatomy of larvae and the lesions caused by them in the gonads of hosts; (4) reporting new host and reporting evidence of host specificity of E. pseudouncinatus between two species of edible pen shells coexisting in the northern Pacific of Mexico; and (5) analyzing the frequency of infested gonads by host sex, size, and gonadal development stage. The molecular analysis confirmed the morphological and histological diagnosis of E. pseudouncinatus larvae infesting gonads of Atrina maura and Pinna rugosa in Ojo de Liebre and San Ignacio lagoons. The morphological characterization of larvae provides internal details of the cephalic bulb (including rows of hooks and ballonets), neural chord, and cell types of the body wall. Histopathological findings such as degenerated and atretic gametes and the displacement of gonadal tissue in hosts infested with E. pseudouncinatus larvae are discussed in terms of temperature anomalies caused by the "Godzilla El Niño". The frequency of infestation increased with shell length and gonadal development in A. maura, with a higher infestation frequency in females versus males observed at both study sites. Our findings expand the list of hosts of E. pseudouncinatus, which was previously unknown as a parasite of P. rugosa. In P. rugosa, infestation frequencies are noticeably lower (<1 %) compared with those observed in A. maura (>30 %) at both study sites, suggesting host-specific requirements or preferences in E. pseudouncinatus larvae.

An improved method for isolating camallanid (Nematoda) spicules for scanning electron microscopy.

In nematodes, the structure of male copulatory organs is a significant taxonomic distinguisher and includes the morphometry of the spicules. The description of these structures mainly relies on the study of whole mounts using light microscopy. In rare instances, protruding spicules have been described with scanning electron microscopy. Even fewer studies have described the ultrastructure of isolated spicules following their isolation. In the present study, two different methods of spicule isolation were performed on two parasitic camallanid nematodes, Procamallanus (Procamallanus) pseudolaeviconchus Moravec & van As, 2015 and Paracamallanus cyathopharynx (Baylis, 1923), from African sharptooth catfish to determine the practicality and efficiency of the methodologies. The first method involved using sharpened tungsten needles and microdissection of the spicule pouch to free the spicules, followed by soft tissue digestion if necessary. Alternatively, the spicules were isolated through mechanical release instead of dissection in a method developed in the current study. This involved freeing the spicules from surrounding soft tissue by placing live specimens between a coverslip and a glass slide in a drop of water and exerting pressure with small rotational movements. Both methods yielded favourable results, but Method 2 is recommended for future studies due to the many advantages.

Spirocamallanus delirae n. sp. (Nematoda, Camallanidae), a parasite of Propimelodus eigenmanni (Siluriformes: Pimelodidae) from the Brazilian Amazon.

A new species of Spirocamallanus Olsen, 1952 (Camallanidae), is described based on specimens found parasitizing Propimelodus eigenmanni (Siluriformes), an Amazonian fish. The new species has buccal capsule with 15-19 spiral ridges, males with caudal alae supported by 3 pairs of precloacal and 6 pairs of postcloacal papillae, and two terminal spikes on tail end, and females with a digitiform projection ending in two small spikes on tail end. The new species shares characteristics with a group of Neotropical Spirocamallanus that are characterized by the presence of caudal alae, 3 pairs of precloacal papillae, unequal spicules and the presence of spines on the tail tip of males. Several species of this group have been reported from marine environments, in contrast with Spirocamallanus delirae n. sp., which occurs in Amazon freshwaters. Among the Brazilian congeners placed in the referred morphological group are S. rarus, S. freitasi, S. macaensis, and S. halithophus, the last two being parasites of marine fishes. The new species differs from S. rarus (3-4), S. macaensis (12-15), and S. halithophus (10-15) based on the number of spirals in the buccal capsule and from S. fretasi based on the morphology of the larger spicule that is bifid in the former and undivided in the new species. The present description of Spirocamallanus delirae n. sp. adds new data to the biodiversity of parasites from freshwater siluriform catfish in the Neotropical region.

Morphological description and molecular characterization of Ancyracanthus electrophori n. sp. (Gnathostomatoidea: Gnathostomatidae): a new nematode parasitic in the electric eel Electrophorus varii (Gymnotiformes: Gymnotidae), from the Brazilian Amazon.

A new species of Ancyracanthus, parasite of the electric eel Electrophorus varii, in the Brazilian Amazon, is described based on morphological and molecular characterization. Ancyracanthus electrophori n. sp. differs from the two congeners namely, Ancyracanthus pinnatifidus and Ancyracanthus schubarti, based on the structure of cephalic appendages, number and arrangement of caudal papillae in males, vulva very close to anus in females, eggs with smoothly mamillated shell, host taxon and geographical origin. Moreover, the new species is the first in the genus to be described with thorny cuticular rings and to be observed with the use of scanning electron microscopy (SEM). The morphology of A. pinnatifidus and A. schubarti is still poorly-known and should be revised in details; however, the separation between them and the new species was clear. Genetic characterization based on 28S rDNA and cytochrome c oxidase subunit I (cox1) mtDNA partial sequences, performed for the first time in Acyracanthus, along with phylogenetic reconstructions using both genetic markers, placed Ancyracanthus electrophori n. sp. in a suggestive basal position within Gnathostomatidae. Phylogenetic reconstructions using cox1 sequences also suggested lack of monophyly in the genera Gnathostoma and Spiroxys and, consequently, in the subfamilies Gnathostominae and Spiroxyinae. However, such results are preliminary. With the first genetic characterization and observations using SEM in Ancyracanthus, resulting in the discovery of a new species and in the expansion of the geographical occurrence of the genus to Amazonian fish, an important step towards a better understanding of these nematodes has been taken.

Heth longquani sp. n.(Rhigonematomorpha: Hethidae)obligate commensalistic nematode of camballoid millipede (Spirostreptida: Cambalopsidae) from Viet Nam.

A new nematode species, Heth longquani sp. n. (Hethidae, Ransonematoidea, Rhigonematomorpha, Rhabditida) is described from the camballoid millipede, Chonecambala crassicauda from Thanh Ha province, Viet Nam. The morphological features of this new species were studied with brightfield and scanning electron microscopies. Partial sequences of LSU rDNA and Cox1 mtDNA are provided. The phylogeny of the nematodes of the genus Heth Cobb, 1898 is discussed.

Morphologic and genetic characterization of Pterygodermatites (Mesopectines) valladaresi n. sp. (Nematoda, Rictulariidae), a parasite of the mouse Mus musculus (Rodentia, Muridae) from the Canary Islands (Spain).

A new rictulariid nematode Pterygodermatites (Mesopectines) valladaresi n. sp., parasite of the house mouse Mus musculus (Rodentia: Muridae) in the Canary Islands (Spain) is described by means of light and scanning electron microscopy. The new species belongs to the subgenus Mesopectines characterized by a more or less dorsal orientation of the buccal capsule, the presence of three oesophageal teeth, the morphology of the oral denticles and the Spirurida type of arrangement of caudal papillae in males. The most discriminant characteristics between the new species and the existing species in the subgenus Mesopectines are (a) the number of cuticular projection pairs (62-64), (b) the size of right and left spicules (respectively, 62-90 µm and 123-139 µm), (c) the number of midventral fans in males (3-4), (d) the number of prevulvar/total cuticular projection pairs (38-42/63-71), (e) the posterior differentiation of combs into spines in relation to the position of the vulva and (f) the anterior position of the vulva in relation to the oesophagus-intestine junction in females. Parasitized hosts and geographical distribution are also useful criteria to distinguish P. (Me.) valladaresi n. sp. from the remaining species of the subgenus. In addition, the cox1 sequence of the new species is provided and compared with available data of related species.

Title: Caractérisation morphologique et génétique de Pterygodermatites (Mesopectines) valladaresi n. sp. (Nematoda, Rictulariidae), un parasite de la souris Mus musculus (Rodentia, Muridae) des îles Canaries (Espagne). Abstract: Un nouveau nématode rictulaire, Pterygodermatites (Mesopectines) valladaresi n. sp., parasite de la souris domestique Mus musculus (Rodentia, Muridae) aux îles Canaries (Espagne) est décrit par microscopie optique et électronique à balayage. La nouvelle espèce appartient au sous-genre Mesopectines caractérisé par une orientation plus ou moins dorsale de la capsule buccale, la présence de trois dents œsophagiennes, la morphologie des denticules buccaux et le type Spirurida d'arrangement des papilles caudales chez les mâles. Les caractéristiques les plus discriminantes entre la nouvelle espèce et les espèces existantes du sous-genre Mesopectines sont (a) le nombre de paires de projections cuticulaires (62­64), (b) la taille des spicules droit et gauche (respectivement, 62­90 µm et 123­139 µm), (c) le nombre de bourrelets cuticulaires médio-ventraux chez les mâles (3­4), (d) le nombre de peignes prévulvaires par rapport au nombre total de peignes (38­42/63­71), (e) la transformation en épines des peignes après la vulve et (f) la position antérieure de la vulve par rapport à la jonction œsophage-intestin chez les femelles. Les hôtes parasités et la répartition géographique sont également des critères utiles pour distinguer P. (Me.) valladaresi n. sp. des autres espèces du sous-genre. De plus, la séquence du cox1 de la nouvelle espèce est fournie et comparée aux données disponibles sur les espèces apparentées.

The first genetic characterization of Setaria marshalli (Nematoda, Spirurida) with reliable DNA barcoding based on a mitochondrial genetic marker.

Setaria marshalli is a mosquito-borne filarial nematode that causes infection in calves younger than two years old. In the present study, nematodes were obtained from a calf in Japan and morphologically identified as S. marshalli. Additionally, the partial cytochrome oxidase subunit I (COI) region (596 bp) was analyzed for the first time to establish a reliable DNA barcode. Nucleotide sequences of COI were identical among the seven worms obtained. The COI region can be a useful marker for species discrimination in the case of S. marshalli since nucleotide variations observed between the closest congener, Setaria cervi (51/596 bp), were sufficient to allow species discrimination. However, the phylogenetic relationship of S. marshalli with its congeners was unclear in a maximum likelihood tree. We found that the partial COI sequence of S. marshalli analyzed in the present study matched a relevant section of the complete mitochondrial genome of S. labiatopapillosa that was deposited in the International Nucleotide Sequence Database. This finding suggests that S. marshalli was misdiagnosed as S. labiatopapillosa in a previous study. It is crucial to conduct accurate morphological analyses to obtain reliable molecular information regarding Setaria nematodes.

Title: Première caractérisation génétique de Setaria marshalli (Nematoda, Spirurida) avec un code-barres ADN fiable basé sur un marqueur génétique mitochondrial. Abstract: Setaria marshalli est une filaire transmise par les moustiques qui provoque une infection chez les veaux de moins de deux ans. Dans la présente étude, les nématodes ont été obtenus à partir d'un veau au Japon et identifiés morphologiquement comme S. marshalli. De plus, la région partielle de la sous-unité I (COI) de la cytochrome oxydase (596 pb) a été analysée pour la première fois afin d'établir un code-barres ADN fiable. Les séquences nucléotidiques de COI étaient identiques parmi les sept vers obtenus. La région COI peut être un marqueur utile pour la discrimination des espèces dans le cas de S. marshalli puisque les variations de nucléotides observées avec le congénère le plus proche, Setaria cervi (51/596 pb) étaient suffisantes pour permettre la discrimination des espèces. Cependant, la relation phylogénétique de S. marshalli avec ses congénères n'était pas claire dans un arbre à maximum de vraisemblance. Nous avons constaté que la séquence COI partielle de S. marshalli analysée dans la présente étude correspondait à une section pertinente du génome mitochondrial complet de S. labiatopapillosa qui a été déposée dans la base de données internationale de séquences de nucléotides. Cette découverte suggère que S. marshalli a été diagnostiqué à tort comme S. labiatopapillosa dans une étude précédente. Il est crucial de mener des analyses morphologiques précises pour obtenir des informations moléculaires fiables concernant les nématodes du genre Setaria.

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha.

BACKGROUND: The infraorder Rhigonematomorpha comprises a group of obligate parasitic nematodes of millipedes (Arthropoda: Diplopoda). The current species identification of Rhigonematomorpha nematodes remains mainly based on morphological features, with molecular-based identification still in its infancy. Also, current knowledge of the phylogeny of Rhigonematomorpha is far from comprehensive. METHODS: The morphology of Rhigonematomorpha nematodes belonging to the genus Rhigonema, collected from the millipede Spirobolus bungii Brandt (Diplopoda: Spirobolida) in China, was studied in detail using light and scanning electron microscopy. Five different genetic markers, including the nuclear small ribosomal subunit (18S), internal transcribed spacer (ITS) and large ribosomal subunit (28S) regions and the mitochondrial cox1 and cox2 genes of these Rhigonematomorpha nematodes collected from China and Rhigonema naylae collected from Japan were sequenced and analyzed using Bayesian inference (BI) and Assemble Species by Automatic Partitioning (ASAP) methods. Phylogenetic analyses that included the most comprehensive taxa sampling of Rhigonematomorpha to date were also performed based on the 18S + 28S genes using maximum likelihood (ML) and BI methods. RESULTS: The specimens of Rhigonema collected from S. bungii in China were identified as a new species, Rhigonema sinense n. sp. Striking variability in tail morphology was observed among individuals of R. sinense n. sp. ASAP analyses based on the 28S, ITS, cox1 and cox2 sequences supported the species partition of R. sinense n. sp. and R. naylae, but showed no evidence that the different morphotypes of R. sinense n. sp. represent distinct genetic lineages. BI analyses also indicated that R. sinense n. sp. represents a separated species from R. naylae based on the cox1 and cox2 genes, but showed that R. naylae nested in samples of R. sinense n. sp. based on the ITS and 28S data. Phylogenetic results showed that the representatives of Rhigonematomorpha formed two large clades. The monophyly of the families Carnoyidae and Ichthyocephalidae and the genus Rhigonema was rejected. The representatives of the family Ransomnematidae clustered together with the family Hethidae with strong support. CONCLUSIONS: A new species of Rhigonematomorpha, R. sinense n. sp. is described based on morphological and molecular evidence. ASAP analyses using 28S, ITS, cox1 and cox2 data indicate the striking variability in tail morphology of R. sinense n. sp. as intraspecific variation, and also suggest that partial 28S, ITS, cox1 and cox2 markers are effective for molecular identification of Rhigonematomorpha nematodes. The phylogenetic results support the traditional classification of Rhigonematomorpha into the two superfamilies Rhigonematoidea and Ransomnematoidea, and indicate that the families Carnoyidae and Ichthyocephalidae and the genus Rhigonema are non-monophyletic. The present phylogeny strongly supports resurrection of the family Brumptaemiliidae, and also indicates that the family Ransomnematidae is sister to the family Hethidae.

Status of Onchocerca volvulus (Spirurida: Onchocercidae) Transmission and Effect of Climatic Variables on the Vector Population Dynamics After Two Decades of Ivermectin-based Preventive Chemotherapy in the Mbam Valley (Centre Region, Cameroon).

Entomological indicators of onchocerciasis transmission and the effect of climatic variables on the vector population dynamics were investigated in two first-line villages after more than two decades of mass drug administration with ivermectin. Female blackflies were collected in two villages (Bayomen and Biatsota) using human landing method for a period of 12 months. Blackflies were dissected and entomological indices were computed. Monthly temperature, precipitation, and humidity were collected and the Spearman correlation rank test was used to assess the relationship between biting rates and climatic variables. The highest biting rates (62,280 bites/human/month in Bayomen and 42,090 bites/human/month in Biatsota) were recorded during the long rainy season (November). The Onchocerca volvulus transmission was greater during the long dry season in both villages, with a peak at the beginning of the long dry season in Biatsota (100 infective larvae/human/month), and at the middle of the long dry season in Bayomen (92 infective larvae/human/month). No correlation was found between biting rates and selected climatic variables in the two villages. This study revealed that onchocerciasis transmission is ongoing in the study area despite almost 25 years of Community-Directed Treatment with Ivermectin. In accordance with WHO recommendations, vector control should be used in combination with mass drug administration to accelerate transmission interruption of onchocerciasis. To be optimal, this vector control should be implemented during the long dry season (November to March) when water volumes are low and transmission potentials are high.