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The present study provides the first ultrastructural data on the digenean Gonocerca phycidis belonging to the family Gonocercidae. Live adults digenean were collected from the stomach of the marine fish Gephyroberyx darwinii (Teleostei: Trachichthyidae) caught in the Atlantic Ocean, off Dakar (Senegal). This is also the first report of G. phycidis from Senegal and this host species. The mature spermatozoon exhibits (i) two axonemes with the 9 + ‘‘1’’ pattern of the Trepaxonemata, (ii) a lateral expansion associated with external ornamentations and without cortical microtubules, (iii) two types of external ornamentation of the plasma membrane located in the anterior extremity of the spermatozoon, (iv) two bundles of cortical microtubules in the mitochondrial and nuclear areas of the spermatozoon, (v) one mitochondrion and (vi) a nucleus. The maximum number of cortical microtubules is located in the median part of the spermatozoon. Moreover, the mature spermatozoon of G. phycidis presents some peculiarities. The presence of a lateral expansion without cortical microtubules associated with external ornamentations is described here, for the first time, in digenean spermatozoa. The presence of two elongated bundles of cortical microtubules is also reported for the first time in the superfamily of Hemiuroidea. However, the ultrastructure of the posterior spermatozoon extremity confirms that already described in other hemiuroidean species.

This work is the first ultrastructural study of spermatozoa in a species of Digenea belonging to the genus Labracetabulum. Labracetabulum gephyroberici parasitizes the digestive tract of the teleost fish Gephyroberyx darwinii (Trachichtyidae) captured in the Atlantic Ocean near Dakar (Senegal). This is also the first report of L. gephyroberici from Senegal. The mature spermatozoon is filiform tapered at both ends and exhibits the general organization described in most Opecoelideans, namely two axonemes of the 9 + “1” pattern of the Trepaxonemata, an anterior electron-dense material, an external ornamentation associated with a row of cortical microtubules, spine-like bodies, two mitochondria and two bundles of cortical microtubules. However, the mature spermatozoon of L. gephyroberici exhibits some particularities: a short first axoneme which does not reach the nuclear region and the position of the second mitochondrion which reaches almost the posterior part of the mature spermatozoon. The second mitochondrion is still present after the disappearance of the second axoneme. The morphology of the posterior extremity corresponds to the Opecoelidean type described by Quilichini et al. (2010).

The ultrastructure of the mature spermatozoa of Tergestia clonacantha and T. laticollis collected from the digestive tracts of fishes from New Caledonia is described using transmission electron microscopy and compared to that of related species. The spermatozoa of the two species exhibit the general pattern described in most digeneans, namely two axonemes with the 9 + "1" pattern of the Trepaxonemata, nucleus, mitochondrion, cortical microtubules, an external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The spermatozoa of T. clonacantha and T. laticollis show the same ultrastructural model with some specificities in each case, particularly in the disposition of the structures in the posterior extremities of the spermatozoon. This study confirms that ultrastructural characters of the mature spermatozoon are useful tools for the phylogenetic analysis of the Digenea.Étude comparative des caractéristiques ultrastructurales des spermatozoïdes mûrs de deux Fellodistomidae, Tergestia clonacantha et T. laticollis, et contribution à la connaissance phylogénétique des Gymnophalloidea.L’ultrastructure des spermatozoïdes mûrs de Tergestia clonacantha et T. laticollis, prélevés dans le tube digestif de poissons de Nouvelle-Calédonie, est décrite par microscopie électronique à transmission et comparée à celle d’espèces apparentées. Les spermatozoïdes des deux espèces présentent la structure générale décrite chez la plupart des digènes, à savoir deux axonèmes du type 9 + « 1 » des Trepaxonemata, un noyau, une mitochondrie, des microtubules corticaux, des ornementations externes de la membrane plasmique, des corps épineux et des granules de glycogène. Les spermatozoïdes de T. clonacantha et T. laticollis présentent le même modèle ultrastructural avec quelques spécificités dans chaque cas, notamment dans la disposition des structures aux extrémités postérieures du spermatozoïde. Cette étude confirme que les caractères ultrastructuraux du spermatozoïde mûrs sont des outils utiles pour l’analyse phylogénétique des Digenea.

This study provides the first ultrastructural data on the mature spermatozoon of Aephnidiogenes senegalensis (Digenea, Lepocreadioidea, Aephnidiogenidae) parasite of the teleost fish Pomadasys jubelini (Haemulidae) captured near the coast of Dakar (Senegal). This is also the first ultrastructural data on the spermatozoon in the genus Aephnidiogenes. The mature spermatozoon of A. senegalensis is filiform, tapered at both ends and exhibits the general pattern described in the Lepocreadioidea, namely two axonemes of the 9 + ‘1’ pattern, an antero-lateral electron dense material, a nucleus, two mitochondria, external ornamentation of the plasma membrane in the anterior region of the spermatozoon, granules of glycogen and two bundles of parallel cortical microtubules. A peculiarity of the spermatozoon of A. senegalensis is the structure of the apical electron-dense material.

The mature spermatozoon of Sclerodistomum italicum is filiform, tapered at both ends and shows the following features: 2 axonemes of the 9+"1" pattern of the Trepaxonemata, mitochondrion, nucleus and parallel cortical microtubules. The specific features of the spermatozoon of S. italicum include the simultaneous presence of two types of extramembranous ornamentations, the presence of short cortical microtubules in the anterior part of the spermatozoon and the presence of only one bundle of cortical microtubules in the median part of the spermatozoon. Thus far these structures are known only in the Hemiuroidea. The presence of filamentous ornamentation in the anterior extremity of the spermatozoon has not previously been described in the Sclerodistomidae. Similar to spermatozoa of other hemiuroideans, S. italicum lack spine-like bodies described in spermatozoa of many digenean taxa. The posterior extremity of the spermatozoon exhibits the same ultrastructural characteristics typical of the Hemiuroidea.

Sclerodistomoides pacificus is the only species described now in Sclerodistomoididae. We present in this paper the first ultrastructural data of the mature spermatozoon of a species from the genus Sclerodistomoides. Adult specimens of S. pacificus (Digenea: Hemiuroidea: Sclerodistomoididae), were parasites of the gall-bladder of the teleost fish Cheilopogon pinnatibarbatus captured in the Atlantic Ocean, near Dakar (Senegal). The male gamete is a filiform cell which exhibits a similar ultrastructural organization to that reported in most species belonging to the Hemiuroidea with two axonemes of the 9 + ‘1′ pattern of trepaxonematans, a nucleus, a mitochondrion, external ornamentation of the plasma membrane not associated with cortical microtubules and located in the anterior region of the spermatozoon, and parallel cortical microtubules disposed in one side of the spermatozoon. However, the present study allowed describing for the first time a moniliform mitochondrion in the Hemiuroidea. The presence of a moniliform mitochondrion and the absence of filamentous external ornamentation described in other Hemiuridae: Lecithochirium microstomum, L. musculus and Hemiurus appendiculatus are a good tool for phylogenetic purposes in the Hemiuroidea. Moreover, spermatological organisation and model are discussed in context with those of previous studies in the Hemiuroidea.

Spermatological characteristics of the troglotrematid digenean Nephrotrema truncatum, a parasite of the shrew Crocidura russula, have been investigated by means of transmission electron microscopy. The ultrastructural study reveals that the mature spermatozoon of N. truncatum exhibits many ultrastructural characters previously described in most gorgoderoideans. These are two axonemes of the 9+'1' trepaxonematan pattern, four attachment zones, a lateral expansion, an external ornamentation of the plasma membrane associated with spine-like bodies and cortical microtubules, and in the posterior part of the anterior spermatozoon region, two bundles of parallel cortical microtubules with the maximum number located in the anterior part of the spermatozoon, a nucleus, two mitochondria, and granules of glycogen. The obtained results are compared with those of other digeneans, particularly the Gorgoderoidea. The sperm cells gorgoderoideans are of type IV, characterised by a 9+'1' pattern of axonemes, the presence of an external ornamentation associated with cortical microtubules and located in the posterior area of the anterior extremity, the presence of two bundles of cortical microtubules, the maximum number of cortical microtubules located in the anterior region of the spermatozoon, and the presence of generally two mitochondria. However, dicrocoeliids and troglotrematids have spermatozoa with ornamentation of the plasma membrane and lateral expansions.

International audience; We describe here the mature spermatozoa of three species of bucephalids, namely Bucephalus margar-itae, Rhipidocotyle khalili and Prosorhynchus longisaccatus. This study provides the first ultrastructural data on the genera Bucephalus and Rhipidocotyle and enabled us to confirm the model of the mature spermatozoon in the Bucephalinae. The spermatozoon exhibits two axonemes with the 9 + ''1'' pattern of the Trepaxonemata, one of which is very short, lateral expansion, external ornamentation of the plasma membrane located in the anterior extremity of the spermatozoon and associated with cortical microtubules, spine-like bodies, a mitochondrion, and a nucleus. The maximum number of cortical microtubules is located in the anterior part of the spermatozoon. However, more studies are needed to elucidate if spine-like bodies are present in all the Bucephalinae or not. In the Prosorhynchinae, the mature spermatozoon exhibits a similar ultrastructural pattern. Some differences are observed, particularly the ax-oneme lengths and the arrangement of the spine-like bodies. The posterior extremity of the spermatozoon in the Bucephalinae exhibits only the nucleus, but prosorhynchines have microtubules.; Dans cette étude, nous décrivons les spermatozoïdes mûrs de trois espèces de bucephalidés, à savoir Bucephalus margaritae, Rhipidocotyle khalili et Prosorhynchus longisaccatus. Ces premières données ultrastructurales pour les genres Bucephalus et Rhipidocotyle nous ont permis de confirmer le modèle du spermatozoïde chez les Bucephalinae. Le spermatozoïde comprend deux axonèmes de type 9 + ‘‘1’’ des Trepaxonemata, l’un d’entre eux étant très court, une expansion latérale, une ornementation externe de la membrane plasmique située au niveau de l’extrémité antérieure du spermatozoïde et associée avec des microtubules corticaux, des corps en forme d’épines, une mitochondrie et un noyau. Le nombremaximum de microtubules corticaux est situé dans la partie antérieure du spermatozoïde. Toutefois, des études supplémentaires seraient nécessaires pour vérifier si les corps en forme d’épines sont présents chez tous les Bucephalinae. Chez les Prosorhynchinae, le spermatozoïde mûr présente une structure similaire. Quelques différences sont toutefois observées, notamment au niveau de la longueur des axonèmes et de la disposition des corps en forme d’épines. L’extrémité postérieure du spermatozoïde chez les Bucephalidae est caractérisée par la présence du noyau seul, alors que les Prosorhynchinae ont des microtubules.

The mature Podocotyloides magnatestis spermatozoon exhibits two axonemes of the 9 + “1” pattern of the Trepaxonemata, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, spine-like bodies, an external ornamentation of plasma membrane, glycogen granules and an antero-lateral electron-dense material. These ultrastructural characteristics have already been described in the Opecoeloidea species studied so far. However, P. magnatestis spermatozoon is distinguished by the fact that its electron-dense material is laterally located on the side of the second axoneme. Moreover, the posterior spermatozoon extremity, characterized by the presence of the nucleus, is observed for the first time in the Opecoelidae.

International audience; The mature spermatozoon of Hemiurus appendiculatus exhibits the general pattern described in most of the digenean namely, two axonemes of the 9 + "1" pattern of the Trepaxonemata, a nucleus, a filiform mitochondrion, external ornamentations of the plasma membrane and parallel cortical microtubules located on one side of the spermatozoon. In this study, we show for the second time in a digenean spermatozoon the presence of microtubules of the second axoneme associated each in a short length with an external ornamentation, seven cortical microtubules, a terminal bulge in the anterior spermatozoon extremity separate from the remainder of the spermatozoon by a transverse constriction and the simultaneous presence of the external ornamentation of the plasma membrane with a filamentous ornamentation. The external ornamentations have a differentiated distribution, cover almost the anterior region of the spermatozoon, are more abundant around the first axoneme and extend backwards over a short distance around the second axoneme. This study also allowed us to reveal for the first time the existence in the Hemiuroidea of an axoneme that begins to disrupt before reaching the front end of the mitochondrion.

Spermatological characteristics are described for the first time in the genus Neomultitestis Machida, 1982, belonging to the family Lepocreadiidae Odhner, 1905. Adult Neomultitestis aspidogastriformis were collected from the digestive tract of Platax teira, caught off New Caledonia. The mature spermatozoon of N. aspidogastriformis is described by transmission electron microscopy (TEM). It includes two axonemes with 9 + “1” pattern of Trepaxonemata, an antero-lateral electron-dense material, attachment zones, two mitochondria, a nucleus, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies, and granules of glycogen. Certain ultrastructural characteristics of the spermatozoon, especially the antero-lateral electron-dense material, are shared by N. aspidogastriformis and all species of the superfamily Lepocreadioidea studied so far. The antero-lateral electron-dense material, present in different families of lepocreadioids, supports the monophyletic status of the superfamily. We also list several ultrastructural characteristics which characterize the mature spermatozoon of the Lepocreadioidea.

The wide biodiversity and economic importance of digeneans have motivated a great deal of research in the last decade, focussing on their phylogenetic positions. Molecular research was instrumental for our understanding of phylogeny in the Digenea, but spermatological studies have also provided many results, which are potentially useful for phylogeny; however, the complete spermatological data set has never been reviewed in a whole phylogenetic perspective. Spermatological data are now available for more than 100 species, belonging to 15 superfamilies and 46 families. In this paper, we try to summarize the current knowledge about sperm structure in the digeneans and propose a classification of digenean spermatozoa into five basic models. The main ultrastructural characters used are (1) the type of axoneme, (2) the lateral expansion, (3) the association ‘external ornamentation of the plasma membrane + cortical microtubules’, (4) the field of cortical microtubules and its number, (5) the location of the external ornamentation, (6) the location of the maximum number of cortical microtubules and (7) the number of mitochondria. We also outline the most interesting features for phylogenetic inference and their possible value in the context of digenean systematics, phylogeny and evolution. Associations between sperm models and superfamilies were found as follows: Type 1 in the Schistosomatoidea; Type 2 in the Hemiuroidea; Type 3 in the Opecoeloidea, Lepocreadioidea, Haploporoidea and Opisthorchioidea; Type 4 in the Gorgoderoidea, Microphalloidea, Plagiorchioidea and Gymnophalloidea; Type 5 in the Echinostomatoidea, Microscaphidioidea, Paramphistomoidea, Pronocephaloidea and Brachylaimoidea.

The mature spermatozoon of Anomotaenia quelea exhibits an apical cone of electron-dense material and two helicoidal crest-like bodies. The apical cone near its base is surrounded by a lucent cytoplasm and a spiraled layer of cortical microtubules. The crest-like bodies are of different lengths, spiraled and make an angle of 30–40° to the hypothetical spermatozoon axis. The axoneme is of the 9 + ‘1’ trepaxonematan pattern and is surrounded by a periaxonemal sheath of electron-dense material. The cytoplasm contains in regions III and IV numerous electron-dense granules situated between the periaxonemal sheath and the cortical microtubules. The posterior extremity of the spermatozoon of A. quelea exhibits a nucleus and a disorganized axoneme and cortical microtubules. This type of posterior extremity of the mature spermatozoon has never been described previously in a Dilepididae. Similarly, two crest-like bodies have not been observed before in a dilepidid cestode.

This study presents the ultrastructure of the mature spermatozoon of Prosorchis palinurichthi (Digenea: Hemiuroidea: Sclerodistomidae), parasite of the digestive tract of the teleost fish Schedophilus velaini ( Sauvage, 1879 ) (Centrolophidae) captured in the Atlantic Ocean, near Dakar (Senegal). This is a first report of P. palinurichthi from Senegal and from this host species. The mature spermatozoon of P. palinurichthi is filiform, tapered at both ends and exhibits the general pattern described in the hemiuroids: two axonemes of the 9 + ‘1’ pattern of trepaxonematans, a nucleus, a mitochondrion, external ornamentation of the plasma membrane in the anterior region of the spermatozoon and parallel cortical microtubules disposed in one side of the spermatozoon except in the anterior spermatozoon extremity and in the mitochondrial region. However, the particularities of the spermatozoon of P. palinurichthi are the presence of cortical microtubules at the anterior extremity, a great number of cortical microtubules (up to 25) in the region II of the spermatozoon, an elongate nucleus longer than the mitochondrion and the absence of spinelike bodies. Our results are discussed in context with those of previous studies in the Digenea in general and particularly in the Hemiuroidea.

The ultrastructure of the mature spermatozoon of the type genus of the Plagiorchiidae Plagiorchis elegans (Rudolphi, 1802), a parasite of the Golden hamster, Mesocricetus auratus is described. This study is the first ultrastructural study of the spermatozoon of a Plagiorchis, the second of a plagiorchiid species and only the third in the Plagiorchioidea. Previously data on spermatozoon ultrastructure existed only for the plagiorchiid Enodiotrema reductum and the omphalometrid Rubenstrema exasperatum. The mature spermatozoon of P. elegans exhibited the general pattern described in most digenean species, namely two axonemes of the 9 + "1" Trepaxonemata pattern, nucleus, mitochondria, external ornamentation of the plasma membrane, spine-like bodies, and glycogen granules. However, the rather typical expansion of the plasma membrane is not found in P. elegans. Another peculiarity of the spermatozoon of P. elegans is the presence of a structure called thin cytoplasm termination. Spermatozoon ultrastructure of P. elegans is compared with that of E. reductum and R. exasperatum. Spermatozoon of P. elegans conforms to the general pattern described in E. reductum. Thus, this study further expands our knowledge on the spermatozoon ultrastructure among the members of the Plagiorchioidea, one of the most phylogenetically derived groups of the digenea.

Spermatological characteristics of species from two monorchiid genera,OpisthomonorchisandParamonorcheides, have been investigated, for the first time, by means of transmission electron microscopy. The ultrastructural study reveals that the mature spermatozoon ofOpisthomonorchis dinemaandParamonorcheides selarisshare several characters such as the presence of two axonemes of different lengths showing the 9+“1” pattern of the Trepaxonemata, a nucleus, two mitochondria, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies, granules of glycogen and similar morphologies of the anterior and posterior extremities. The slight differences between the male gamete ofO. dinemaandP. selarisare the length of the first axoneme and the position of the second mitochondrion. This study also elucidates the general morphology of the spermatozoon in all monorchiid species described so far, which corresponds to a unique spermatozoon type. Other interesting finds concern the spermatological similarities between monorchiid spermatozoa and the mature spermatozoon reported in the apocreadiidNeoapocreadium chabaudi. These similarities allow us to suggest a close phylogenetical relationship between the Monorchiidae and the Apocreadiidae, although more studies are needed, especially in the unexplored taxa.

International audience; Recent studies have revealed a large diversity of Plasmodium spp. among African great apes. Some of these species are related to Plasmodium falciparum, the most virulent agent of human malaria (subgenus Laverania), and others to Plasmodium ovale, Plasmodium malariae and Plasmodium vivax (subgenus Plasmodium), three other human malaria agents. Laverania parasites exhibit strict host specificity in their natural environment. Plasmodium reichenowi, Plasmodium billcollinsi, Plasmodium billbrayi and Plasmodium gaboni infect only chimpanzees, while Plasmodium praefalciparum, Plasmodium blacklocki and Plasmodium adleri are restricted to gorillas and Plasmodium falciparum is pandemic in humans. This host specificity may be due to genetic and/or environmental factors. Infrastructures hosting captive primates, such as sanctuaries and health centres, usually concentrate different primate species, thus favouring pathogen exchanges. Using molecular tools, we analysed blood samples from captive non-human primates living in Gabon to evaluate the risk of Plasmodium spp. transfers between host species. We also included blood samples from workers taking care of primates to assess whether primate-human parasite transfers occurred. We detected four transfers of Plasmodium from gorillas towards chimpanzees, one from chimpanzees to gorillas, three from humans towards chimpanzees and one from humans to mandrills. No simian Plasmodium was found in the blood samples from humans working with primates. These findings demonstrate that the genetic barrier that determines the apparent host specificity of Laverania is not completely impermeable and that parasite exchanges between gorillas and chimpanzees are possible in confined environments.

In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a considerable impact on the transmission dynamics of S. haematobium in Niakhar, due to the nature of the epidemiological system with seasonal transmission. Thus, to maintain this benefit and continue to reduce the morbidity of urogenital schistosomiasis, other approaches should be integrated into the strategy plans of the National program to achieve the goal of urogenital schistosomiasis elimination in seasonal foci in Senegal., Author Summary Urogenital schistosomiasis represents a serious cause of morbidity and mortality in S. haematobium endemic countries. Treatment with praziquantel (PZQ) is effective at reducing or eliminating active infection, but does not prevent reinfection that remains a continuing problem in high-risk communities, especially in areas where contacts with infested water are inevitable. The efficacy of PZQ treatment is challenged by regular re-infection in high risk communities due to frequent contact with water infested with snails carrying the larvae of S. haematobium. A large number of countries have initiated schistosomiasis control and elimination programs based on repeated PZQ mass drug administration (MDA). However, little information is available on the impact of repeated treatment on S. haematobium transmission dynamics in areas where transmission occurs seasonally in temporary water bodies. This observational study assessed the effect of annual repeated cohort treatment with PZQ over 3 years on the seasonal transmission dynamics of S. haematobium in nine villages in Niakhar district, District. Repeated annual treatments have a considerable impact on the transmission dynamics of S. haematobium in Niakhar. The prevalence of S. haematobium was dramatically reduced from 57.7% in 2011 to 10.1% in 2014. The reinfection rate did not exceed 10% from 2012 to 2014. Also, the rate of infested Bulinid snails decreased from 0.8% in 2012 to 0.5% in 2013. These results suggest that it may be possible to implement urogenital schistosomiasis elimination strategies in the Niakhar district and other seasonal transmission areas in Senegal if praziquantel MDAs are carried out in combination with other measures such as health education, improvement of access to clean water and snail control.

Le Sénégal est situé sur la limite nord-ouest de l’aire de répartition du Chimpanzé. On y trouve la sous-espèce de l’Afrique de l’Ouest, Pan troglodytes verus, qui est inscrite dans la catégorie des espèces en danger d’extinction sur la liste rouge de l’Union Mondiale pour la Nature. Elle est la plus menacée des trois sous-espèces de chimpanzés. Dans cette région, il vit dans des conditions climatiques de savane très dures en plus de la forte pression anthropique exercée sur l’habitat. Le dernier recensement effectué dans cette région estime une population d’environ 400 à 500 individus. Plusieurs études ont été effectuées sur le chimpanzé dans cette région, mais peu ont porté sur son comportement alimentaire. Sur le site de Fongoli (12°41N, 12°30W), nous avons effectué un suivi de l’écologie nutritionnelle de ce primate non humain. Pour cela, nous avons d’abord procédé par observation directe afin d’établir une liste des espèces consommées et la manière dont elles sont consommées. Ensuite, ces aliments sont échantillonnés pour des analyses au laboratoire. Les analyses nous ont permis de mettre en évidence et de quantifier les sucres, la matière grasse, les fibres solubles dans les détergents (neutres, acides et lignines) et la présence ou non de tannin. Nos résultats ont montré que ces chimpanzés ont un régime principalement frugivore, mais consomment également des feuilles, des fleurs, des graines. Ils sont aussi insectivores et consomment des protéines d’origine animale. L’analyse nutritive des aliments montre un régime riche en sucre provenant essentiellement des fruits, une quantité importante de fibres et de matière grasse. Cependant, l’accès à cette nourriture devient de plus en plus difficile à cause du facteur anthropique. Nous pensons que la maîtrise du comportement alimentaire du chimpanzé dans cette région est d’une importance capitale pour une meilleure conservation de cette ressource.Je tiens à exprimer toute ma reconnaissance à mes encadreurs, les Prs Cheikh Tidiane Ba et Jill D. Pruetz, les Drs Papa Ibnou Ndiaye et Stacy Marie Lindshield. Je les remercie de m’avoir encadré, orienté, aidé et conseillé. J’adresse mes sincères remerciements à tous les professeurs, intervenants, et à toutes les personnes qui par leurs paroles, leurs écrits, leurs conseils et leurs critiques ont guidé mes réflexions et ont accepté de me rencontrer et de répondre à mes questions durant mes recherches. Je remercie vivement la société Mako Exploration Company pour l’ouverture d’esprit de son Administrateur Général Adjoint M. Fally Diop et du Manager du Bureau Environnement et Social Paul Cannon ainsi que pour leur soutien moral et financier. J’ai aimablement été accueilli par cette société. J’ai aussi pu bénéficier de l’aide précieuse du Capitaine Cheikh Sylla responsable du bureau Environnement. Je souhaite enfin remercier Dondo Kante, Michel Sadiakho et tout le village de Fongoli qui ont facilité mon intégration et mes travaux de terrain.

International audience; The mature spermatozoon of Bothriocotyle sp. is filiform and tapered at both extremities. It possesses 2 axonemes of unequal length, showing the 9 + "1" pattern of Trepaxonemata. The anterior extremity exhibits a crest-like body. Thereafter, the crest-like body disappears, and the first axoneme is surrounded by a ring of cortical microtubules (about 27 units) that persist until the appearance of the second axoneme. This ring of cortical microtubules is characteristic only for species of Bothriocephalidea and represents a very useful phylogenetic character. The spermatozoon cytoplasm is slightly electron-dense and contains numerous electron-dense granules of glycogen in several regions. The anterior and posterior extremities of the spermatozoon lack cortical microtubules. The posterior extremity of the spermatozoon of Bothriocotyle sp. possesses a nucleus and a disorganized axoneme, which also characterizes spermatozoa of the Echinophallidae studied to date.

Spermiogenesis in the proteocephalidean cestode Barsonella lafoni de Chambrier et al., 2009 shows typical characteristics of the type I spermiogenesis. These include the formation of distal cytoplasmic protrusions forming the differentiation zones, lined by cortical microtubules and containing two centrioles. An electron-dense material is present in the apical region of the differentiation zone during the early stages of spermiogenesis. Each centriole is associated to a striated rootlet, being separated by an intercentriolar body. Two free and unequal flagella originate from the centrioles and develop on the lateral sides of the differentiation zone. A median cytoplasmic process is formed between the flagella. Later these flagella rotate, become parallel to the median cytoplasmic process and finally fuse proximodistally with the latter. It is interesting to note that both flagellar growth and rotation are asynchronous. Later, the nucleus enlarges and penetrates into the spermatid body. Finally, the ring of arching membranes is strangled and the young spermatozoon is detached from the residual cytoplasm. The mature spermatozoon presents two axonemes of the 9 + ‘1’ trepaxonematan pattern, crested body, parallel nucleus and cortical microtubules, and glycogen granules. Thus, it corresponds to the type II spermatozoon, described in almost all Proteocephalidea. The anterior extremity of the gamete is characterized by the presence of an apical cone surrounded by the lateral projections of the crested body. An arc formed by some thick and parallel cortical microtubules appears at the level of the centriole. They surround the centriole and later the first axoneme. This arc of electron-dense microtubules disorganizes when the second axoneme appears, and then two parallel rows of thin cortical microtubules are observed. The posterior extremity of the male gamete exhibits some cortical microtubules. This type of posterior extremity has never been described in proteocephalidean cestodes. The ultrastructural features of the spermatozoon/spermiogenesis of the Proteocephalidea species are analyzed and compared.

The mature spermatozoon of Cricocephalus albus is filiform, tapered at both ends and shows the following features: 2 axonemes of different lengths presenting the 9 + “1” trepaxonematan pattern, 2 bundles of parallel cortical microtubules, a mitochondrion and a nucleus. Nevertheless, the particularity of the spermatozoon of C. albus is its anterior extremity with an apical electron-dense material associated with extramembranar ornamentation, a cytoplasmic dorsolateral expansion and spine-like bodies. To our knowledge, such an anterior extremity of the spermatozoon has not previously been described from a species of the superfamily Pronocephaloidea. Our study provides new data on the mature gamete of C. albus in order to improve our understanding of the pronocephaloidean phylogenetic relationships.

Spermiogenesis and the ultrastructural organisation of the spermatozoon of the trypanorhynch cestode Aporhynchus menezesi Noever, Caira, Kuchta et Desjardins, 2010 are described by means of transmission electron microscopy. Type I spermiogenesis of A. menezesi starts with the formation of a differentiation zone containing two centrioles separated by an intercentriolar body constituted by five electron-dense plates. Each centriole gives rise to a free flagellum, which grows at an angle of 90 degrees in relation to a median cytoplasmic process. The nucleus and cortical microtubules elongate along the spermatid body. Later, both flagella rotate and fuse with the median cytoplasmic process. At the final stage of spermiogenesis, the young spermatozoon is detached from the residual cytoplasm by a narrowing of the ring of arched membranes. The mature spermatozoon is a long and filiform cell, tapered at both ends, lacking mitochondria. It is characterized by the presence of two axonemes of the 9+'1' trepaxonematan pattern, the absence of crested bodies, the presence of parallel cortical microtubules and nucleus. This pattern corresponds to the type I spermatozoon of the eucestodes. The anterior extremity of the spermatozoon is characterized by the presence of an arc-like row of up to seven parallel cortical microtubules that partially surrounds the first axoneme. These anterior cortical microtubules are thicker than the posterior microtubules and, consequently, the sperm cell of A. menezesi exhibits two types of cortical microtubules. Another interesting aspect is the presence of alpha-glycogen rosettes. This spermatological pattern is similar to that observed in the spathebothriidean and diphyllobothriidean cestodes.

Spermiogenesis in Diplodiscus subclavatus begins with the formation of the zone of differentiation presenting two centrioles associated with striated roots and an intercentriolar body. The latter presents seven electron-dense layers with a fine central plate and three plates on both sides. The external pair of these electron-dense layers is formed by a granular row. Each centriole develops into a free flagellum, both of them growing orthogonally in relation to the median cytoplasmic process. After the flagellar rotation and before the proximodistal fusion of both flagella with the median cytoplasmic process four attachment zones were already observed in several cross-sections indicating the area of fusion. Spinelike bodies are also observed in the differentiation zone before the fusion of flagella. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon that detaches from the residual cytoplasm. The mature spermatozoon of D. subclavatus shows all the classical characters observed in Digenea spermatozoa such as two axonemes of different length of the 9 + “1” trepaxonematan pattern, nucleus, mitochondrion, two bundles of parallel cortical microtubules and granules of glycogen. However, some peculiarities such as a well-developed lateral expansion associated with external ornamentation of the plasma membrane and spinelike bodies combined with their area of appearance distinguish the ultrastructural organization of the sperm cells of D. subclavatus from those of other digeneans.

Marigo, A.M., Bâ, C.T. and Miquel, J. 2011. Spermiogenesis and spermatozoon ultrastructure of the dilepidid cestode Molluscotaenia crassiscolex (von Linstow, 1890), an intestinal parasite of the common shrew Sorex araneus. —Acta Zoologica (Stockholm) 92: 116–125. Spermiogenesis in Molluscotaenia crassiscolex begins with the formation of a differentiation zone containing two centrioles. One of the centrioles develops a flagellum directly into the cytoplasmic extension. The nucleus elongates and later migrates along the spermatid body. During advanced stages of spermiogenesis, a periaxonemal sheath appears in the spermatid. Spermiogenesis finishes with the appearance of a single helicoidal crested body at the base of the spermatid and, finally, the narrowing of the ring of arched membranes causes the detachment of the fully formed spermatozoon. The mature spermatozoon of M. crassiscolex exhibits a partially detached crested body in the anterior region of the spermatozoon, one axoneme, twisted cortical microtubules, a periaxonemal sheath, and a spiralled nucleus. The anterior spermatozoon extremity is characterized by the presence of an electron-dense apical cone and a single spiralled crested body, which is attached to the sperm cell in the anterior and posterior areas of region I, whereas in the middle area it is partially detached from the cell. This crested body is described for the first time in cestodes. The posterior extremity of the male gamete exhibits only the disorganizing axoneme. Results are discussed and compared particularly with the available ultrastructural data on dilepidids sensu lato.

We studied patterns of variation in cestode communities of 3 abundant rodent species that live in sympatry in the Niayes of the Retba Lake, Western Senegal. We evaluated whether the host species have the same parasites and, within host species, whether the variability in parasite community is related to intrinsic (sex, age of the host individual) or extrinsic (habitat, season) factors. Arvicanthis niloticus was parasitized by 2 cestode species, namely Inermicapsifer madagascariensis and the highly dominant Raillietina trapezoïdes . Raillietina baeri was the only cestode species found in Mastomys erythroleucus , and there was no cestode in M. huberti . Prevalence and abundance levels of cestodes were very high in A. niloticus , especially in adults. Seasonal and habitat effects were found in both cestode communities of M. erythroleucus and A. niloticus . Local host specificity and abundance/prevalence levels suggested variations in the interaction between rodents and cestode intermediate host species among habitats and seasons.

International audience; BackgroundSchistosoma haematobium is the most widespread schistosome species in Senegal and occurs in several regions of the country especially in the Sudan-Sahelian zone. The aims of the study were i) to determine the freshwater species ii) to ascertain the role of the identified snail species in the transmission of S. haematobium and iii) to study the impact of drought on the snails.MethodsSnails were sampled each year in 17 sites from July to November-December 2012 and 2013. At each snail survey, snails were grouped by village, counted, identified according to shell morphology and the rates of schistosome cercarial shedding recorded. The shell height of the snails collected in July was measured and classified into four groups according to their size in order to determine those that are open to aestivation.ResultsB. senegalensis and B. umbilicatus were the only snails intermediate hosts collected in the Niakhar study area. B. senegalensis is found in all the 17 sampling sites while B. umbilicatus was only found in one site out of the many surveyed. The total number of B. senegalensis collected in 2012 and 2013 was 1032 and 8261 respectively. A total of 901 and 6432 B. senegalensis were tested for Schistosoma spp. infestation in 2012 and 2013 respectively. For B. umbilicatus, 58 snails were collected and tested in 2012. In 2013, 290 were collected and 281 tested. The overall rates of schistosome cercarial shedding were 0 % in 2012 and 0.12 % in 2013 for B. senegalensis and 13.79 and 4.98 % in 2012 and 2013 respectively for B. umbilicatus. For both species collected in July, size group 3 individuals (7–9.9 mm) were the most numerous, 63.6 and 57.8 % for B. senegalensis and B. umbilicatus respectively. B. umbilicatus was reported for the first time in the region of Fatick located in the old ecological zone of Sine-Saloum, is able to maintain Schistosoma spp. larvae during 7 months of drought and may transmit the disease in early July, increasing the period and the risk of transmission.ConclusionThis study recommends an adaptation of snail control strategies at pond cycles and ecology of the snails in these seasonal foci. Malacological control strategies must take into account these phenomena of drought resistance and the capacity of some snails to maintain parasite during aestivation. The treatment of ponds with Bayluscide at the end of the rainy season in November and upon onset of rains in July would be more advantageous to the control of snails thereby reducing transmission of urogenital schistosomiasis in the Niakhar area.

We present in this paper the first ultrastructural study of the spermatozoon of species of the genus Bianium Stunkard, 1930, namely Bianium plicitum and Bianium arabicum belonging to the family Lepocreadiidae. Specimens are parasites of the tetraodontid teleosts Lagocephalus laevigatus caught in the Atlantic Ocean and Lagocephalus sceleratus caught in Pacific Ocean, respectively. Live worms were fixed and processed for transmission electron microscopy. Observations of numerous cross and longitudinal sections of the spermatozoa of B. plicitum and B. arabicum demonstrated the general pattern described in all previously studied Lepocreadioidea, namely two axonemes with 9+ "1" pattern of Trepaxonemata, two mitochondria, a nucleus, parallel cortical microtubules, and an external ornamentation of the plasma membrane associated with spine-like bodies. The maximum number of cortical microtubules and the external ornamentation were not located at the anterior extremity of the spermatozoon but at a more posterior level, as in all the species of Lepocreadioidea studied to date. Differences observed between spermatozoa of B. plicitum and B. arabicum were observed in: (1) the location of the first mitochondrion, (2) size of cortical microtubules which were longer in B. arabicum than in B. plicitum, and (3) the order of the disappearance of the axonemes, mitochondrion, and cortical microtubules toward the posterior region of the spermatozoon. Only the nucleus reaches into the posterior extremity of the spermatozoon in these two species. The general pattern of the spermatozoon described in these two species exhibit the general model in the genus Bianium.

The male gametes of Brachylecithum eliomydis (Digenea, Dicrocoeliidae) a parasite of Eliomys querci-nus “the garden dormouse” caught in France were described by micrographs of transmission electronmicroscopy (TEM). The mature spermatozoon of B. eliomydis presents classical characteristics earlydescribed in digenean species such as the two axonemes of different lengths with the 9+“1” pattern ofthe trepaxonematan platyhelminthes, two bundles of parallel cortical microtubules, two mitochondria,a nucleus and granules of glycogen. Moreover, several characteristics, described in the spermatozoon ofB. eliomydis, vary within digenean taxa. Those are (1) the morphology of anterior and posterior sperma-tozoon extremities, (2) the external ornamentation of the plasma membrane and its association or notwith cortical microtubules, (3) the presence or absence of spine-like bodies and (4) the number of cor-tical microtubules and their organization into one or two parallel bundles. Using these four criteria, themorphology of themature spermatozoon B. eliomydis was compared to that other dicrocoellids,brachycoeliids, paragonimids and troglotrematids species described so far. The general morphology ofthe spermatozoon described in B. eliomydis, could characterize the family Dicrocoeliidae.© 2015 Elsevier GmbH. All rights reserved.

International audience; The mature spermatozoa of Stephanostomum murielae and Stephanostomoides tenuis are described by transmission electron microscopy. They present several ultrastruc-tural features previously reported in other digeneans. Their spermatozoa possess two axonemes of different length showing the 9 + '1' trepaxonematan pattern, four attachment zones, two mitochondria (with an anterior moniliform one in S. murielae), a nucleus, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. The main differences between the mature spermatozoon of S. murielae and S. tenuis are the maximum number of cortical microtubules, the morphology of the anterior spermatozoon extremity and the anterior mitochondrion. This study is the first concerning members of the family Acanthocolpidae. The main ultra-structural characteristics discussed are the morphology of the anterior and posterior spermatozoon extremities, antero-lateral electron dense material, external ornamen-tations, spine-like bodies and number and morphology of mitochondria. In addition, the phylogenetic significance of all these ultrastructural features is discussed and compared to molecular results in order to highlight the complex relationships in the Digenea.

International audience; BackgroundHuman schistosomiasis is a significant health problem in Sub-Saharan Africa. In Niakhar, West central Senegal, the transmission of S. haematobium occurs seasonally between July and November. No control measures have been implemented despite high prevalence reported in previous studies. This aim of this study was to i) determine the current prevalence of S. haematobium in children at Niakhar, ii) assess the efficacy of one dose of PZQ (40 mg/kg) against S. haematobium and iii) monitor reinfection.MethodsThe current study was carried out in a cohort of 329 children aged five to 15 years enrolled from six villages in Niakhar to determine the efficacy of one dose of PZQ, as well as reinfection. Parasitological screening was performed in June 2011 to determine the baseline prevalence of S. haematobium, and then a single dose of PZQ was administered to all selected subjects in the transmission season in August 2011. The efficacy of PZQ treatment and reinfection were monitored respectively five weeks after in September 2011 and from February to March 2012.ResultsAt baseline, the overall prevalence and the heavy intensity of infection were 73.2 % and 356.1eggs/10 ml of urine. Significant differences in the prevalence and intensity of S. haematobium infection were noted between villages. A single dose of PZQ significantly reduced the prevalence of S. haematobium infection from 73.2 % to 4.6 % and the geometric mean intensity of infection from 356.1 to 43.3 eggs/10 ml of urine. The cure rates ranged from 89.4 % to 100 %. The egg reduction rates also ranged from 77.6 % to 100 %. Two to three months after the period of transmission, the overall rate of reinfection was 12.6 % and was significantly higher in male children than in female children. The overall prevalence at this period was 13.8 %, which was significantly lower than the prevalence at baseline (73.2 %).ConclusionThe Niakhar study area remains a hot spot of urinary schistosomiasis in Senegal with differences in transmission between villages. This study suggests that when transmission is strictly seasonal, Praziquantel shows the expected efficacy in reducing the prevalence and intensity of infection, but also a significant effect on the occurrence of reinfection.

The mature Helicometroides atlanticus spermatozoon exhibits an anterior electron-dense material, two axonemes of the 9 + “1” pattern, a nucleus, two mitochondria, extramembranous ornamentations located at the level of the first mitochondrion and cortical microtubules arranged into two fields: a ventral field corresponding to the mitochondrial side and a dorsal field corresponding to the nuclear side. It lacks of spine-like body and a cytoplasmic expansion as in Monorchis parvus the only species of Monorchioidea which spermatozoon has been described until now. Nevertheless, it is distinguished from M. parvus by the presence of an anterior electron-dense material and two axonemes which appear one after the other.

Background Urinary schistosomiasis is a parasitic disease that exists in all regions of Senegal. It is a major public health issue in this country. This study was carried out to determine the prevalence and intensity of this parasitosis in 12 villages of Niakhar (Fatick, Senegal). Methods A total of 210 schoolchildren, aged 7 to 15 years, were enrolled in this study, and urine samples were examined for Schistosoma haematobium eggs using a standard urine filtration technique. Results Of these children, 121 (57.6%) were found to be infected with a mean geometric count of 185 eggs per 10 ml of urine. The disease was present in all surveyed villages, and the prevalence ranged from 14.3% to 92.8%. The prevalence of infection was significantly correlated with increasing age and was higher in boys. Infection intensity was significantly higher in boys but did not significantly differ with age. Significant relationships between i) water contact or access to running water and ii) the prevalence or intensity of urinary schistosomiasis were also noted. Conclusions The district of Niakhar is endemic for urinary schistosomiasis, with a high intensity of infection. A control program to decrease the prevalence and intensity should be implemented in this area to improve community health.

International audience; The presence of Cucullanid nematodes was investigated in 10 individuals of Mugil bananensis, 115 Mugil cephalus, 109 Mugil curema, 89 Liza dumerili, 37 Liza falcipinnis, and 40 Liza grandisquamis, all collected from the Saloum estuary in Senegal, West Africa. Cucullanids were found only in intestines removed from M. curema and were identified using light microscopy. The results showed that 13 individuals of Mugil curema were found to be parasitized by 22 adult nematodes of a species new to science, Cucullanus djilorensis n. sp. (prevalence 11.9%, intensity 1.7). This species differs from all other species of the genus Cucullanus by a number of features including the form of the esophagus, the number and distribution of caudal papillae, the position of the excretory pore, and the length of the spicules. Cucullanus djilorensis n. sp. is the first species of the genus described from an estuarine fish in West Africa.

International audience; The spermatological characteristics of Collyricloides massanae (Digenea: Collyriclidae), a parasite of Apodemus sylvaticus caught in France, were studied by means of transmission electron microscopy. The mature sperm of C. massanae presents two axonemes of different lengths with the 9 + "1" pattern of the Trepaxonemata, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies, one mitochondrion, a nucleus and granules of glycogen. An analysis of spermatological organisation emphasised some differences between the mature spermatozoon of C. massanae and those reported in the Gorgoderoidea species studied to date, specially belonging to the families Dicrocoeliidae, Paragonimidae and Troglotrematidae. The ultrastructural criteria described in C. massanae such as the morphology of both anterior and posterior spermatozoon extremities, the association "external ornamentation+cortical microtubules", the type 2 of external ornamentation and the spine-like bodies would allow us to bring closer the Collyriclidae to Microphalloidea. However, further ultrastructural and molecular studies are needed particularly in the unexplored taxa in order to fully resolve the phylogenetic position of the Collyriclidae.

International audience; This study provides the first ultrastructural data of spermatozoa in the genus Lecithochirium. The spermatozoa of L. microstomum (from Trichiurus lepturus in Senegal) and L. musculus (from Anguilla anguilla in Corsica) exhibit the general pattern described in the great majority of the Digenea, namely two axonemes with the 9 + "1" pattern typical of the Trepaxonemata, one mitochondrion, a nucleus, parallel cortical microtubules and external ornamentation of the plasma membrane. Spermatozoa of L. microstomum and L. musculus have some specific features such as the presence of a reduced number of cortical microtubules arranged on only one side of the spermatozoon, the lack of spine-like bodies and expansion of the plasma membrane. The external ornamentation of the plasma membrane entirely covers the anterior extremity of the spermatozoa. The ultrastructure of the posterior extremity of the spermatozoa corresponds to the pattern previously described in the Hemiuridae, characterized by only singlets of the second axoneme. A particularity of these spermatozoa is the organization of the microtubule doublets of the second axoneme around the nucleus in the posterior part of the spermatozoon.

Spermiogenesis in Vampirolepis microstoma begins with the formation of a nuclear cone and a differentiation zone. This is delimited at the front by arched membranes, bordered by cortical microtubules, and contains two parallel centrioles linked together at their bases by electron-dense, amorphous material. The nuclear cone elongates, becomes filiform, and migrates into the spermatid body. Later, one of the centrioles gives rise to a flagellum that grows at the same pace as the cortical microtubules. Subsequently, 6 crested bodies form and the old spermatid separates from the residual cytoplasm. The mature V. microstoma spermatozoon is filiform and lacks mitochondria. Its anterior end exhibits six crested bodies 100 to 200 nm thick of unequal lengths. The axoneme is of the 9+”1” pattern. The cortical microtubules are spiralized and make an angle of about 20 to 30° to the spermatozoon axis, except at their posterior extremity where they become parallel to this axis. The nucleus is an electron-dense cord coiled in a spiral around the axoneme. The cytoplasm is slightly dense but contains many electron-dense granules in regions III, IV, and V of the spermatozoon. The presence of centrioles linked together at their bases by electron-dense material has never, to our knowledge, been reported in a Platyhelminth. Likewise, a nuclear migration, right from the beginning to the end of spermiogenesis, has never been described in a cestode. In addition, we observe for the first time the existence of six crested bodies in a cestode from a Mammal. Microsc. Res. Tech. 42:218–225, 1998. © 1998 Wiley-Liss, Inc.

Ultrastructural characters of spermiogenesis and the mature spermatozoon of Brachycoelium salamandrae are described by means of transmission electron microscopy. Spermiogenesis begins with the formation of a differentiation zone containing a nucleus, several mitochondria, and two centrioles associated with striated rootlets and with an intercentriolar body between them. The two centrioles originate two free flagella that grow orthogonally to the median cytoplasmic process before fusing with it. The final stage of spermiogenesis is characterized by a constriction of the ring of arched membranes and the liberation of the young spermatozoon. In this final stage a pear shaped electron-dense material appears at the level of centrioles. Spermatozoon of B. salamandrae exhibits two axonemes of different length with the 9+‘1’ trepaxonematan pattern, a nucleus, two mitochondria, two bundles of parallel cortical microtubules and granules of glycogen. Additionally, the spermatozoon of B. salamandrae shows external ornamentations of the plasma membrane and spinelike bodies. The most relevant spermatozoon characters of B. salamandrae are discussed and compared with those of other species belonging to the superfamily Gorgoderoidea.

International audience; A new species of Spirura is described from the stomach of Heliosciurus gambianus and Xerus erythropus (Sciuridae). Considering the number of preanal papillae of males, Babero (1973 ) and Giannetto and Canestri Trotti (1995) proposed the subdivision of the genus into 2 groups; those with 4 pairs of preanal papillae (25 species) and with more than 4 pairs of preanal papillae (4 species). Spirura mounporti n. sp. belongs to the second, with 5 pairs of preanal papillae, and differs from Spirura infundibuliformis (McLeod, 1933) Anderson et al., 1993 , Spirura zapi ( Erickson, 1938 ) Chabaud et al., 1965 , Spirura leiperi Gupta and Trivedi, 1985, and Spirura michiganensis Sandground, 1935 in the number of pairs of pre-cloacal papillae. The new species further differs from other species of the genus in having 21 caudal papillae, in the ratio of spicules:body length, and in its morpho-anatomical characters.

International audience; Pterygodermatites (Mesopectines) quentini n. sp. (Nematoda, Rictulariidae) is described from the murine host Praomys rostratus in the south of the Republic of Mali. It differs from other species of the subgenus by the morphology of the head, which bears four simple cephalic papillae and a nearly axial oral opening, the number of caudal papillae, the number of precloacal cuticular formations, unequal spicules and the ratio of spicule lengths/body length. The use of scanning electron microscopy in combination with conventional light microscopy enabled us to give a detailed description of the morphological characters of this new species.

Summary The mature H. straminea spermatozoon is filiform and lacks mitochondria. It exhibits an apical cone of electron-dense material and eight helicoidal crest-like bodies 50–100 nm in thickness. The cortical microtubules are spiralized and make an angle of about 30° to the spermatozoon axis. The axoneme, of the 9+“1” pattern of the Platyhelminthes, does not reach the extremities of the spermatozoon. The nucleus is a compact cord wound in a spiral around the axoneme. Depending on the level of section it appears annular or crescent-shaped. The cytoplasm exhibits many electron-dense granules in regions III, IV and V of the gamete. A nucleus with both annular and crescent-shaped sections has never been described in a species of the Hymenolepididae. In addition we report for the first time the existence of eight crest-like bodies of different length in the cestodes.

The current study was designed to increase the spermatological ultrastructural database on Digenea, thus contributing to the future establishment of phylogenetic relationships within this group based on ultrastructural characteristics of both spermiogenesis and spermatozoa. Spermiogenesis in Elstia stossichianum begins with the formation of a differentiation zone containing two centrioles, two striated rootlets, a nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. Each centriole develops into a free flagellum growing orthogonally to the median cytoplasmic process. Proximo-distal fusion of the flagella with the median cytoplasmic process occurs after flagellar rotation. Both nucleus and mitochondria migrate before the complete proximo-distal fusion of both flagella with the median cytoplasmic process. Finally, the constriction of the ring of arched membranes gives rise to the young spermatozoon. The mature spermatozoon of E. stossichianum exhibits two axonemes of different length of the 9+‘1’ trepaxonematan pattern, a nucleus, a mitochondrion, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, a lateral expansion, spine-like bodies, cytoplasmic ornamented buttons and granules of glycogen. The formation of cytoplasmic ornamented buttons during the final stages of spermiogenesis is reported here for the first time.

International audience; This study describes the ultrastructural organisation of the spermatozoon of a digenean Enodiotrema reductum (Pligiorchiida: Plagiorchiidae) from the green turtle Chelonia mydas (Linnaeus, 1758). This is the first report of E. reductum from Senegal. The mature spermatozoon of E. reductum is filiform and exhibits two axonemes of the 9 + "1" pattern of the Trepaxonemata, a nucleus, parallel cortical microtubules, an extramembranar ornamentation associated with spine-like bodies and granules of glycogen, among other ultrastructural features. The spermatozoon of E. reductum is distinguished by the presence of a moniliform mitochondrion composed of a bulge associated with a long cord and of a central cytoplasmic expansion. This work represents the first utrastructural study of any representative of the large family Plagiorchiidae. Our results are compared with previously published data on spermatozoa of other digenean taxa.

Spermiogenesis in Robphildollfusium fractum begins with the formation of a differentiation zone containing: two centrioles, each bearing striated rootlets, nucleus, several mitochondria and an intercentriolar body constituted by seven electron-dense layers. The two centrioles originate two free flagella growing orthogonally to the median cytoplasmic process. Later, the free flagella rotate and undergo proximodistal fusion with the median cytoplasmic process. Nuclear and mitochondrial migrations occur before this proximodistal fusion. Finally, the young spermatozoon detaches from the residual cytoplasm after the constriction of the ring of arched membranes. The spermatozoon of R. fractum exhibits two axonemes of different length of the 9 + ‘1’ trepaxonematan pattern, nucleus, two mitochondria, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. Additionally, a shorter axoneme, which does not reach the nuclear region, the presence of an electron-dense material in the anterior spermatozoon extremity and the morphologies of both spermatozoon extremities characterize the mature sperm of R. fractum .

Spermiogenesis and the ultrastructure of the spermatozoon of the bothriocephalidean cestode Clestobothrium crassiceps (Rudolphi, 1819), a parasite of the teleost fish Merluccius merluccius (Linnaeus, 1758), have been studied by means of transmission electron microscopy. Spermiogenesis involves firstly the formation of a differentiation zone. It is characterized by the presence of two centrioles associated with striated rootlets, an intercentriolar body and an electron-dense material in the apical region of this zone. Later, two flagella develop from the centrioles, growing orthogonally in relation to the median cytoplasmic process. Flagella then undergo a rotation of 90° until they become parallel to the median cytoplasmic process, followed by the proximodistal fusion of the flagella with the median cytoplasmic process. The nucleus elongates and afterwards it migrates along the spermatid body. Spermiogenesis finishes with the appearance of the apical cone surrounded by the single helical crested body at the base of the spermatid. Finally, the narrowing of the ring of arched membranes detaches the fully formed spermatozoon. The mature spermatozoon of C. crassiceps is filiform and contains two axonemes of the 9 + '1' trepaxonematan pattern, a parallel nucleus, parallel cortical microtubules, and electron-dense granules of glycogen. The anterior extremity of the gamete exhibits a short electron-dense apical cone and one crested body, which turns once around the sperm cell. The first axoneme is surrounded by a ring of thick cortical microtubules that persist until the appearance of the second axoneme. Later, these thick cortical microtubules disappear and thus, the mature spermatozoon exhibits two bundles of thin cortical microtubules. The posterior extremity of the male gamete presents only the nucleus. Results are discussed and compared particularly with the available ultrastructural data on the former 'pseudophyllideans'. Two differences can be established between spermatozoa of Bothriocephalidea and Diphyllobothriidea, the type of spermatozoon (II vs I) and the presence/absence of the ring of cortical microtubules.