A Review of Sperm Ultrastructural Characters in the Opecoelidae (Digenea) and Their Phylogenetic Implications, with New Data on Peracreadium characis, a Parasite of Diplodus puntazzo in Tunisia.

The spermatozoon ultrastructure of Peracreadium characis (Stossich, 1886) (Digenea: Opecoelidae), an intestinal parasite of the sheephead bream Diplodus puntazzo (Walbaum, 1792) (Sparidae), is described by means of transmission electron microscopy (TEM). The mature spermatozoon possesses two axonemes of the 9+'1' trepaxonematan pattern, an anterior electron-dense material, two mitochondria, a nucleus and parallel cortical microtubules distributed in two bundles. The absence of external ornamentation of the plasma membrane and spine-like bodies are the noteworthy characters that distinguish the spermatozoon of P. characis from those of most opecoelids. In fact, only Helicometra fasciata lacks external ornamentation in the spermatozoon. A comparative study with the remaining opecoelids described so far reveals similarities in the ultrastructural organization of their sperm cells. In addition, the current data on sperm ultrastructure in species of the recognized opecoelid subfamilies are compared, namely the Hamacreadiinae, Helicometrinae, Opecoelinae, Opistholebetinae and Plagioporinae.

Data on New Intermediate and Accidental Hosts Naturally Infected with Angiostrongylus cantonensis in La Gomera and Gran Canaria (Canary Islands, Spain).

Angiostrongylus cantonensis is a metastrongyloid nematode and the etiologic agent of angiostrongyliasis, a disease characterized by eosinophilic meningitis. This emerging zoonotic parasite has undergone great expansion, including in some regions of Europe and America. In the Canary Islands, the parasite was first discovered parasitizing Rattus rattus on the island of Tenerife in 2010. To date, the distribution of this parasite in the Canary Islands has been restricted to the northern zone and the main cities of Tenerife. Using molecular tools for the sentinel species present in the Canary Islands, this study confirmed the presence of the nematode on two other islands in the Canary Archipelago: La Gomera and Gran Canaria. Furthermore, this emerging parasite was detected, besides in the common definitive host R. rattus, in wild Mus musculus and Felis catus and in four terrestrial gastropod species, Limacus flavus, Milax gagates, Insulivitrina emmersoni, and Insulivitrina oromii, two of them endemic to La Gomera, for the first time, increasing the number of non-definitive host species. This study reinforces the expansion character of A. cantonensis and highlights the importance of knowledge about sentinel species for identifying new transmission locations that help prevent and control the transmission of the parasite and, thus, prevent public health problems.

Spermatological Characterization of the Cestode Meggittina gerbilli (Cyclophyllidea: Catenotaeniidae), a Parasite of Gerbils, Gerbillus gerbillus and Gerbillus campestris (Rodentia: Muridae) in Tunisia.

Ultrastructural characters of spermiogenesis and the mature spermatozoon of the cestode Meggittina gerbilli (Cyclophyllidea: Catenotaeniidae), a parasite of the Lesser Egyptian gerbil (Gerbillus gerbillus) and the North African gerbil (Gerbillus campestris) (Rodentia: Muridae) in the Djebel Dahar (South of Tunisia), were studied using transmission electron microscopy. The spermiogenesis of M. gerbilli is of Bâ and Marchand's type III, which is mainly characterized by a proximodistal fusion of a single flagellum with a cytoplasmic extension. In this catenotaeniid, the proximal fusion is preceded by a 90° rotation of the flagellum. The spermatozoon is a Levron et al. type VI, which presents a single axoneme with the 9 + '1' trepaxonematan pattern, a periaxonemal sheath, two crest-like bodies, twisted cortical microtubules, and a spiraled nucleus. The obtained results show similarities with the remaining studied catenotaeniids, namely Catenotaenia pusilla and Skrjabinotaenia lobata. The results are compared and discussed according to several characteristics found in the catenotaeniids and other studied cyclophyllideans.

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.

New Data on Pterygodermatites (Pterygodermatites) plagiostoma Wedl, 1861 (Nematoda, Rictulariidae) Parasite of the Algerian Hedgehog Atelerix algirus Linnaeus, 1758 (Eulipotyphla: Erinaceidae) from the Canary Islands.

A redescription of the rictulariid nematode Pterygodermatites (Pterygodermatites) plagiostoma Wedl, 1861, is made by means of light and scanning electron microscopy, including the first data on male specimens. The morphologic study was based on specimens recovered from two Algerian hedgehogs (Atelerix algirus) from Tenerife and Gran Canaria islands (Canary Archipelago, Spain). The main characteristics of P. (P.) plagiostoma males are the presence of 49-53 pairs of cuticular projections, the presence of one or two midventral precloacal fans (generally one), and the size of two unequal spicules, measuring 98-123 µm (right spicule) and 185-236 µm (left spicule). The cloacal papillae are arranged according to the Ascaridida type. They include two precloacal pairs, an unpaired precloacal papilla, one pair lateral to the cloaca, six postcloacal pairs, and a pair of phasmids near the tail tip. Females are mainly characterized by the presence of 71-77 pairs of cuticular projections, with 43-46 pairs of prevulvar combs, by the differentiation from combs to spines at the level of or slightly posterior to the vulva and by the position of the vulva, located posteriorly to the esophagus-intestine junction. Clear differences were found between P. (P.) plagiostoma and related species of the subgenus P. (Pterygodermatites).

ULTRASTRUCTURE AND CYTOCHEMISTRY OF LATE EMBRYOS AND COTYLOCIDIUM LARVAE OF ROHDELLA AMAZONICA (TREMATODA: ASPIDOGASTREA), FROM THE TROPICAL ESTUARINE FISH, COLOMESUS PSITTACUS.

Developmental ultrastructure of late embryos and cotylocidium larval morphogenesis of Rohdella amazonica, an aspidogastrean parasite of fish, were studied to reveal the functional aspects of larvigenesis within the egg as well as phylogenetically relevant characteristics of the embryos and larvae in this basal trematode group. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard methods of transmission electron microscopy (TEM) and cytochemistry. During late cleavage and rearrangement of the blastomeres, the vitelline syncytium that plays a role in eggshell formation and nutrient provision to the embryo completes its apoptotic degeneration as the embryonic mass grows substantially. Early larval morphogenesis involves cellular positioning that defines the anteroposterior polarity of the differentiating larva. Progressing through larvigenesis, the anterior end forms a muscular oral sucker surrounding the mouth, which leads inward into the pharynx and expanding digestive cavity. At the posterior end, a large disc forms as a precursor to the eventual ventral disc. The fully formed cotylocidium, still within the eggshell, is flexed ventrally, bringing the 2 poles into near juxtaposition. The neodermatan tegument with outwardly projecting small microvilli becomes fully formed, as myocytons, a protonephridial system, and 2 glandular regions occupy the body's interior. The ultrastructural features described here are very similar to those reported for Aspidogaster limacoides from fish and somewhat similar to those reported for Cotylogaster occidentalis from molluscs, but differ from the more diverse larvae of neodermatan taxa that have been studied more extensively.

Myiasis by Cordylobia anthropophaga (Calliphoridae) in rodents from Cape Verde.

PURPOSE: The tumbu fly, Cordylobia anthropophaga (Diptera: Calliphoridae), is widely distributed in continental tropical and subtropical Africa, being the most common cause of furuncular myiasis in Sub-Saharan Africa. The aim of the present work was to analyze the role of rodents as possible reservoirs of C. anthropophaga in Cape Verde, considering the zoonotic character of this fly species. MATERIALS AND METHODS: A total of 150 peridomestic rodents were studied in Santiago island. For the obtained larvae, morphological and molecular characters were analyzed. RESULTS: Cordylobia anthropophaga was found in 6.4% of the peridomestic Rattus rattus analyzed. The present work unveils the presence of C. anthropophaga in rodents of the African archipelago of Cape Verde, introduced probably with West African humans and/or animals. CONCLUSION: The presence in peridomestic animals, and the wide range of species that this fly can affect, entails a zoonotic risk of myiasis by tumbu fly.

ULTRASTRUCTURE OF EGG ENVELOPES AND EARLY EMBRYOS OF ROHDELLA AMAZONICA (TREMATODA: ASPIDOGASTREA) PARASITIC IN BANDED PUFFER FISH, COLOMESUS PSITTACUS.

Egg structure and early embryonic development of the aspidogastrean, Rohdella amazonica, a basal trematode, were studied by transmission electron microscopy (TEM) to gain insight into functional, developmental, and phylogenetic characteristics. Gravid worms were removed from the intestine of naturally infected banded puffer fish Colomesus psittacus, collected from the Bay of Marajó, Paracauari River (Pará, Brazil) and processed by standard TEM methods. By the time of pronuclear fusion, the fertilized zygote was already enclosed in a thick, electron-dense pre-operculate eggshell and an underlying layer of vitellocytes that fused into a vitelline syncytium as they were still secreting their shell granules. When cleavage commenced, a small number of macromeres moved to the area just underneath the eggshell, where they fused to form a single syncytial embryonic envelope. Simultaneously, the smaller blastomeres continued to divide as they maintained contact with each other, but remained separate from the vitelline syncytium. Concurrent with these cellular changes, a thickened knob expanded at one pole of the eggshell and began to form an opercular suture. By the time the operculum was fully formed, the vitelline syncytium had mostly degenerated, while the smaller blastomeres had become cohesive as a single mass that preceded the differentiation and morphogenesis of the cotylocidium larva. The general pattern of cleavage and eggshell formation resembles that of other trematodes and polylecithal cestodes, but the single embryonic envelope has been reported only in a few basal taxa. The only other aspidogastrean studied in detail to date is very similar, indicating close phylogenetic affinity and conservatism within this basal neodermatan and neoophoran group.

Ultrastructural and molecular study of the microsporidian Toguebayea baccigeri n. gen., n. sp., a hyperparasite of the digenean trematode Bacciger israelensis (Faustulidae), a parasite of Boops boops (Teleostei, Sparidae).

A new microsporidian Toguebayea baccigeri n. gen., n. sp., hyperparasite of Bacciger israelensis (Digenea, Faustulidae), parasite of Boops boops (Teleostei, Sparidae) is described by means of transmission electron microscopy. The phylogenetic analysis, based on the SSU rDNA gene, places the new species in the clade containing mainly crustacean-infecting microsporidia of the genus Cucumispora, within superclade V (Marinosporidia) sensu Vossbrinck et al., 2014. Mature spores of T. baccigeri are ovoid, uninucleated and measure 2.5 × 1.4 µm. The number of coils of the polar tube is 8-10. The polaroplast is composed of an external lamellar part and an internal vesicular or granular part. The main differences that distinguish the new genus and new species from the closely related microsporidia include hyperparasitism in a digenean host infecting a marine fish, the geographic distribution (coast of Tunisia), presence of one nucleus at all developmental stages, disporoblastic sporogony, and the absence of sporophorous vacuoles.

TITLE: Étude ultrastructurale et moléculaire de la microsporidie Toguebayea baccigeri n. gen., n. sp., hyperparasite du trématode digène Bacciger israelensis (Faustulidae), parasite de Boops boops (Teleostei, Sparidae). ABSTRACT: Une nouvelle microsporidie Toguebayea baccigeri n. gen., n. sp., hyperparasite de Bacciger israelensis (Digenea, Faustulidae), parasite de Boops boops (Teleostei, Sparidae) est décrite en microscopie électronique à transmission. L'analyse phylogénétique, basée sur l'étude du gène SSU rDNA, place la nouvelle espèce dans le clade qui contient notamment les microsporidies parasites de crustacés du genre Cucumispora, dans le superclade V (Marinosporidia) sensu Vossbrinck et al, 2014. Les spores mûres de T. baccigeri sont ovoïdes, uninucléées et mesurent 2,5 × 1,4 µm. Le nombre de tours de spire décrits par le tube polaire est de 8 à 10. Le polaroplaste est composé d'une partie externe lamellaire et d'une partie interne vésiculeuse ou granuleuse. Les principales différences entre le nouveau genre et la nouvelle espèce et les microsporidies les plus proches sont : l'hyperparasitisme d'un digène parasite d'un poisson marin, la localisation géographique (côtes de la Tunisie), et certains aspects du développement, notamment la présence d'un seul noyau à tous les stades de développement, la sporogonie disporoblastique et l'absence de vacuoles sporophores.

Cryptosporidium spp. in wild murids (Rodentia) from Corsica, France.

Cryptosporidium spp. are worldwide protozoan parasites that can affect to a broad range of vertebrate hosts, including rodents. In the island of Corsica (France), there are no previous data about these protozoa infecting wild rodents. To estimate the distribution and occurrence, a total of 117 wild murine rodents of the species Rattus rattus (84), Mus musculus domesticus (21), Apodemus sylvaticus (11), and Rattus norvegicus (1) were captured in 24 different biotopes. Fecal samples were screened for Cryptosporidium spp. by nested PCR to amplify an 830 bp fragment of the 18S rRNA gene. As general occurrence, 15.4% of the rodents analyzed were positive for Cryptosporidium spp., being detected widely distributed along the island in R. rattus (17.6%) and M. m. domesticus (14.3%). Cryptosporidium viatorum, Cryptosporidium sp. rat genotype II, and Cryptosporidium sp. rat genotype III were successfully identified in R. rattus. The results herein reported provide the first data on Cryptosporidium spp. in wild murine species from a Mediterranean island and constitute the first report of the zoonotic species C. viatorum in R. rattus. Although a low occurrence of Cryptosporidium spp. in murids was obtained and only in one animal the zoonotic species C. viatorum was identified, our results highlight that wild murine rodents from Corsica could mediate in the maintenance and transmission of this protozoan to the environment and other hosts including humans and animals. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rodents from Corsica and their possible public health repercussions.

Ecological Analysis of the Helminth Community of Microtus lusitanicus (Gerbe, 1879) (Rodentia) in Asturias (NW Spain).

The Lusitanian pine vole, Microtus lusitanicus, an endemic fossorial rodent of the Iberian Peninsula, has a burrowing behaviour and prefers to live underground. It feeds on bark and roots causing severe damage to trees. In Asturias (NW Spain), where M. lusitanicus is considered a pest in several orchards, a faunistic-ecological study was carried out to describe the helminth community of this species and the main factors that could influence its helminth component species. For this purpose, our own collection of 710 voles from several orchards of various locations in Asturias was used. Eight helminth species, four cestodes and four nematodes, were found. Statistical non-parametric tests were used to analyse the effects of extrinsic and intrinsic factors on the diversity of the helminth community and species prevalence and abundance. The results show the influence of climate variables, the year and season of capture, as well as host age, on the diversity of the helminth community and the infection parameters of some helminth species, underlining the importance of their life cycles. In addition to shedding light on the helminth community of this rodent in Asturias, the results obtained could be used to improve the biological methods applied to fight the M. lusitanicus pest.

First Coronavirus Active Survey in Rodents From the Canary Islands.

Since the beginning of the 21st century five new coronaviruses inducing respiratory diseases in humans have been reported. These emergences has promoted research on coronaviruses in wildlife. We started the first eco-epidemiological study to screen the presence of coronaviruses circulating in mice and rats of four Canary Islands. Between 2015 and 2019, we obtained fecal samples of three rodent species (150 Mus musculus, 109 Rattus rattus and 1 Rattus norvegicus) captured in urban and rural areas. Fecal samples were analyzed by nRT-PCR and the resulting sequences were compared to known diversity using Bayesian phylogenetic methods. We only found coronavirus RNA in house mice from El Hierro (10.53%), Tenerife (7.02%) and Lanzarote (5.26%) islands. All coronaviruses detected belong to the species Murine coronavirus belonging to the genus Betacoronavirus and subgenus Embecovirus, being all positive house mice captured in anthropogenic environment. The phylogenetic analysis shows that murine coronaviruses from the Canary Islands are related to European murine coronaviruses. Albeit data are still scarce in the region, the most probable origin of M. coronavirus present in the Canary Islands is continental Europe. According to temporal Bayesian phylogenetics, the differentiation between Canary and continental viruses seems to be quite recent. Moreover, murine coronaviruses from El Hierro, Tenerife and Lanzarote islands tend to segregate in different clades. This enlightens the potential role of rodents or other possibly invasive species in disseminating infectious diseases to remote places through exchanges with the continent. It is important to consider these aspects in the sanitary control of islands, for health and biodiversity preservation concerns.

First spermatological data on the digenean genus Ityogonimus derived from the description of sperm characters of Ityogonimus ocreatus (Brachylaimidae: Ityogoniminae).

The present study describes the ultrastructural organization of the spermatozoa of the brachylaimid digenean Ityogonimus ocreatus (Ityogoniminae) by means of transmission electron microscopy (TEM). Live digeneans were collected from the digestive tract of an Iberian mole Talpa occidentalis (Eulipotyphla, Talpidae) captured accidentally during a vole pest control campaign in Priesca (Asturias, Spain). The TEM study reveals that the I. ocreatus sperm are filiform, tapered at both extremities, and have two 9+'1' trepaxonematan axonemes, external ornamentation of the plasma membrane associated with cortical microtubules, spine-like bodies, two bundles of parallel cortical microtubules and one mitochondrion overlapping the anterior part of the nucleus. The external ornamentation of the plasma membrane is located in the posterior part of the anterior region. The maximum number of parallel cortical microtubules (45) is located in the anterior part of the sperm cells. Our results are compared with the available data on the family Brachylaimidae, especially on the other Ityogoniminae studied to date (Scaphiostomum palaearcticum).

A Peculiar Distribution of the Emerging Nematode Angiostrongylus cantonensis in the Canary Islands (Spain): Recent Introduction or Isolation Effect?

Angiostrongylus cantonensis is an emerging zoonotic nematode recognized as the leading cause of eosinophilic meningitis in the word. After its discovery in China, it was recorded in 30 countries worldwide. Recently, it has expanded to new areas such as South America and it has been recently found in the Atlantic island of Tenerife (Canary Islands). In order to characterize the distribution of A. cantonensis in the Canary Islands, the lungs of 1462 rodents were sampled in eight islands of the archipelago over 13 years and were then analyzed for A. cantonensis. Remarkably, the parasite was detected only in Tenerife, in Rattus rattus (19.7%) and Rattus norvegicus (7.14%). They were concretely in the northern part of the island, which had a warmer and more humid climate than the south and main cities. The absence of this nematode in other islands with similar environmental conditions could be explained by an isolation effect or by a recent introduction of the parasite in the islands. Besides, the presence in Tenerife of the most invasive lineage of A. cantonensis reinforced the hypothesis of a recent introduction on this island. This study highlights the need to implement control measures to prevent the expansion to other areas in order to avoid the transmission to humans and other animals.

Análisis descriptivo de la simulación de síntomas psicológicos en una muestra forense / Descriptive analysis of malingered psychological symptoms in a forensic sample

INTRODUCCIÓN: La simulación, definida como intento deliberado de mentir o engañar en relación con una enfermedad o discapacidad, exagerando la sintomatología, con el objetivo de obtener un beneficio personal, es un fenómeno complejo, poco estudiado en nuestro contexto profesional. El objetivo de este estudio fue analizar el modo en que se manifiesta dicho fenómeno en el ámbito forense. MATERIAL Y MÉTODOS: Se seleccionó una muestra incidental de 190 sujetos atendidos en la Unidad de Psicología (IMLCFC) durante 16 meses. Se les administró el Inventario estructurado de simulación de síntomas, a la vez que se valoraban ciertos indicadores clínicos de simulación y otros resultados psicométricos. Se realizó un análisis estadístico descriptivo de la muestra, así como de las correlaciones entre sospecha clínica y psicométrica, y entre sensibilidad del instrumento específico y de los instrumentos genéricos. RESULTADOS: El criterio clínico estructurado para detectar la simulación correlaciona moderadamente con el resultado obtenido en el Inventario estructurado de simulación de síntomas; la puntuación total en esta prueba presenta una correlación positiva, aunque atenuada, con los indicadores de exageración del principal test de psicopatología; la simulación es un estilo de respuesta altamente prevalente en sujetos de la jurisdicción social, con un patrón de respuestas significativamente incrementado respecto al observado en muestras penales. DISCUSIÓN: La valoración de la simulación de síntomas psicológicos en el contexto forense requiere de una estrategia multimétodo que incluya el juicio clínico estructurado, instrumentos específicos de detección y otras pruebas psicométricas complementarias, al efecto de generar validez convergente que contribuya a la detección de dicho fenómeno

INTRODUCTION: Malingering, defined as a deliberate attempt to lie or deceive in connection with an illness or disability, exaggerating the symptomatology, with the aim of obtaining a personal benefit, is a complex phenomenon, seldom studied in our professional context. The objective of this study was to analyse the way in which this phenomenon manifests itself in the forensic field. MATERIAL AND METHODS: An incidental sample of 190 subjects attended in the Psychology Unit (IMLCFC) over 16 months was selected. The Structured Inventory of Malingered Symptomatology (SIMS) was administered to them, while assessing certain clinical indicators of malingering and other psychometric results. A descriptive statistical analysis of the sample was performed, focusing on the correlations between clinical and psychometric suspicion, and on specific vs. generic test sensitivity. RESULTS: The structured clinical criterion to detect malingering correlates moderately with the result obtained in the SIMS; the total score in this test presents a positive, albeit attenuated, correlation with the exaggeration indicators from the main psychopathology test; malingering is a highly prevalent response style in subjects seeking work-related sickness compensation, with a pattern of significantly increased responses compared to that observed in criminal samples. DISCUSSION: The assessment of malingered psychological symptoms in the forensic context requires a multi-method strategy that includes structured clinical diagnosis, specific detection instruments, and other complementary psychometric tests, in order to generate convergent validity that contributes to the detection of this phenomenon

Spermatological characters in the Lepocreadioidea, with first data on Holorchis pycnoporus (Aephnidiogenidae), a parasite of the Striped seabream Lithognathus mormyrus (Sparidae) from the Gulf of Gabes (Tunisia).

The ultrastructural characteristics of the mature spermatozoon of Holorchis pycnoporus (Digenea, Lepocreadioidea, Aephnidiogenidae) are described by means of transmission electron microscopy (TEM). Live worms were collected from the digestive tract of the Striped seabream Lithognathus mormyrus (Teleostei, Sparidae), off the Gulf of Gabès at La Chebba (Tunisia). The ultrastructural study reveals that the male gamete of H. pycnoporus is a filiform cell tapered at both extremities and exhibiting the type III of the digenean spermatozoon proposed by Bakhoum et al. (2017a), characterized by the presence of (1) two axonemes with the 9 + '1' pattern of the Trepaxonemata, (2) external ornamentation of the plasma membrane located in a posterior part of the anterior region of the spermatozoon and associated with cortical microtubules, (3) two bundles of parallel cortical microtubules with maximum number located in the middle part of the spermatozoon, and (4) generally two mitochondria. Moreover, H. pycnoporus shares a set of ultrastructural characteristics with the studied Aephnidiogenidae such as: (1) two 9+'1' axonemes of different lengths, (2) an anterior electron-dense material, (3) mitochondrion/a, (4) an external ornamentation of the plasma membrane associated with cortical microtubules, and (5) two bundles of parallel cortical microtubules with their maximum number (around 24 microtubules) located in the middle or posterior part of the spermatozoon. In the Aephnidiogenidae, the mature spermatozoon exhibits a similar ultrastructural pattern. Some differences are observed, particularly the location of maximum number of cortical microtubules and the number of mitochondria. The presence of the anterolateral electron-dense material is the major particularity in species belonging to the Lepocreadioidea. This anterior dense material could be a synapomorphy for the superfamily and an ultrastructural argument supporting the monophyletic status of the Lepocreadioidea (Bray and Cribb, 2012).

Pathogenic Leptospira species in rodents from Corsica (France).

Leptospirosis is a worldwide emerging zoonotic disease caused by Leptospira species, that in some patients develop severe forms with high mortality. In France, Corsica is the area where the highest incidences have been reported. The present study was focused on the analysis of pathogenic Leptospira species in rodents of Corsica, as these micromammals are the main natural reservoirs of the bacteria, in order to identify the circulating species and to locate possible risk focuses of transmission, as no previous study on the presence of Leptospira species has been carried out in the island. Rattus rattus, Rattus norvegicus, Apodemus sylvaticus and Mus musculus domesticus were captured in the proximity of water sources along Corsica, the detection of pathogenic Leptospira species was carried out by amplification of the LipL32 gene. The bacteria were found in all the rodent species analyzed and widely. The general prevalence was 10.4%, reaching the maximum value in Bastia (45%). Leptospira interrogans and Leptospira borgpetersenii were identified by phylogenetic analysis, but also two sequences which corresponded to an unnamed Leptospira species, only previously found in rodents of New Caledonia. The high incidence of human leptospirosis in Corsica could be partially explained by the wide distribution of pathogenic Leptospira species identified in this study. Also, the presence of an unknown pathogenic species of Leptospira in an area with high prevalence, may be involved in the higher incidence of Leptospirosis in this island, however, the zoonotic capacity of this species remains unknown. The results obtained are interesting for public health since all positive samples were found near water sources and one of the routes of transmission of leptospirosis is contact with contaminated water. This information could help the competent entities to take preventive measures, reducing the incidence of human leptospirosis in Corsica.

Ultrastructure and cytochemistry of intrauterine embryonic and larval stages of Ityogonimus lorum (Digenea: Brachylaimidae) involving transitory development of ciliated miracidia.

Results of the present study provide ultrastructural evidence that miracidial morphogenesis is fully completed within the intrauterine eggs while in the most posterior uterine regions of Ityogonimus lorum, a digenean parasite of an Iberian mole, Talpa occidentalis (Eulipotyphla, Talpidae). Using transmission electron microscopy (TEM), the ultrastructural characteristics of diverse cell types and their organelles of these developing embryos and fully formed miracidia within the eggshell were examined. The eggshell and embryonic envelopes are similar to those described previously by many authors for other digeneans. However, the developing miracidia are unique among previously described digeneans in possessing transitory cilia during larvigenesis, but completely lacking cilia in fully formed miracidium larvae. The evidence for completion of miracidial maturation in intrauterine eggs is based on the presence of the following structures: (1) transitional stage of ciliated differentiating miracidial epithelium; (2) apical and lateral glands, characteristic for digenean miracidia; and (3) fully developed germinative cells grouped together in the germinative sac localized in the posterior region of the miracidium. The protonephridial system with its characteristic flame cells and the nervous system with diverse types of neurons and nerve centers, which are characteristic for other digenean species reported until now, are absent from all these developmental stages of I. lorum. Based on these observations, we hypothesize that the life cycle of I. lorum is entirely terrestrial, involving passive transmission by ingestion of eggs containing unciliated miracidia to the first intermediate host.

Sperm characters in the Hemiuridae (Digenea): first data on Aphanurus stossichii (Aphanurinae) and Ectenurus lepidus (Dinurinae).

The present work provides the first ultrastructural analysis of spermatozoa of two digeneans (Aphanurus stossichii (Monticelli, 1891) and Ectenurus lepidus Looss, 1907) belonging to the unexplored subfamilies of the Hemiuridae, namely, the Aphanurinae and the Dinurinae. In March 2019, these hemiurids were collected respectively from the digestive tract of the bogue Boops boops (Teleostei, Sparidae) and the Atlantic horse mackerel Trachurus trachurus (Teleostei, Carangidae) captured in the coastal zone of the Mediterranean Sea, off La Chebba (Tunisia). The ultrastructural study reveals that both spermatozoa exhibit the Bakhoum et al.'s type II of the digenean sperm cells characterized by the presence of two 9+'1' axonemes, an external ornamentation of the plasma membrane not associated with cortical microtubules and located in the anterior part of the spermatozoon, a single bundle of cortical microtubules, the maximum number of cortical microtubules located in a middle part of the sperm cell, and one mitochondrion. Moreover, they share several ultrastructural features with the studied spermatozoa of Hemiuridae such as the presence of two axonemes with the 9+'1' trepaxonematan pattern, a reduced number of parallel cortical microtubules organized into one field with their maximum number located in the median (A. stossichii) or posterior (E. lepidus) part of the spermatozoon, an external ornamentation of the plasma membrane in the anterior part of the spermatozoon, one mitochondrion, a nucleus, and a small amount of glycogen granules. However, the two studied hemiurids could be distinguished by the morphology of the anterior and posterior spermatozoon extremities and the presence of mitochondrial matrix granules in A. stossichii.

Sperm characters of the aspidogastrean Rohdella amazonica (Aspidogastridae, Rohdellinae), a parasite of the banded puffer fish Colomesus psittacus.

The ultrastructural characteristics of the mature spermatozoon of the aspidogastrean Rohdella amazonica (Aspidogastridae, Rohdellinae) were studied by means of transmission electron microscopy. The sperm cell shows two axonemes of the 9 + '1' trepaxonematan pattern of Platyhelminthes, parallel cortical microtubules, a well-developed lateral expansion, external ornamentation of the plasma membrane, one mitochondrion, an electron-dense ring, a nucleus and granules of glycogen. The present results were compared with those observed in the aspidogastreans studied to date and in other Platyhelminthes. The lateral expansion and the electron-dense ring are typical characters for aspidogastreans. Although a lateral expansion has been described in other Platyhelminthes such as monogeneans and digeneans, the Aspidogastrea shows a much larger lateral expansion with both peripheral and internal microtubules. The dense ring is observed as a cylinder in a longitudinal view and shows a more granular appearance in sperm cells from the seminal vesicle in comparison to a more electron-dense appearance in sperm cells from the seminal uterine receptacle.