First Study of Ascaris lumbricoides from the Semiwild Population of the Sumatran Orangutan Pongo abelii in the Context of Morphological Description and Molecular Phylogeny.

There is little evidence that the already described and accepted taxa of ascarids (Ascaris lumbricoides, A. suum, and A. ovis) infecting individuals of taxonomically distant groups (hominids, pigs, sheep, goats, and dogs) can be genetically or morphologically distinguished. However, despite described morphological differences, e.g., due to intraspecific variation, these are insufficient for species determination and may indicate differences amongst ascarids because of cross infections, hybrid production, and specific adaptations to hosts. Herein, the results of a molecular and morphological analysis of ascarids parasitising Sumatran orangutans (Pongo abelii Lesson, 1827) in native populations are presented. The research took place in the Bukit Lawang area, Indonesia, in 2009. Throughout the year, fresh faecal samples were collected regularly from 24 orangutans, and all were examined for the presence of nematode adults. Only five adult worms from two orangutan females were found during regular collection. Using the integrative taxonomic approach, the nematodes found were identified as A. lumbricoides. The significance of the find and its rarity is documented by the fact that this is the first confirmed finding of adult ascarids from an original orangutan site (not from a zoo) in more than 130 years (including the long-term study spanning the last 20 years focusing on orangutan parasites and natural antiparasitic drugs). More accurate morphometric parameters and genetic differences for the identification of ascarids were established. These parameters will be helpful for other findings in great apes and will also be suitable for further and precise determination of this parasite. The details distinguishing between male and female specimens are also stated and well defined. A comprehensive evaluation of the situation of Ascaris species parasitising orangutans, including a comparison with previously described orangutan parasite (i.e., A. satyri-species inquirenda), is discussed.

Eudiplozoon nipponicum in focus: monogenean exhibiting a highly specialized adaptation for ectoparasitic lifestyle.

Developmental stages of the diplozoid monogenean Eudiplozoon nipponicum, comprising oncomiracidium, diporpa, juvenile, and adult, were investigated using light and scanning electron microscopy in conjunction with confocal scanning laser microscopy in order to examine body organization and identify explicit morphological adaptations to the ectoparasitic life in each stage. The parasite exhibits a complex digestive tract well equipped for hematophagous feeding. It consists of a mouth opening with prominent buccal suckers, eversible pharynx with adjacent glandular structures, and a blind-ending gut with cecal lining. Glandulo-muscular organs, located apically and opened into the mouth corner, are considered to be a part of the digestive tract. Based on our observations of pharynx eversion and in light of the presence of several glandular or gland-like structures, we propose a new hypothesis on the possibility of extracorporeal digestion of this parasite. The hindbody bears an attachment apparatus, comprising haptor, lobular extensions, and tegumental folds, responsible for the parasite's firm attachment to the host gills. The possibility of buccal suckers assisting in the parasite's translocation while searching for an optimal niche or their temporary attachment function during feeding is discussed. The body of each compound adult (i.e., permanent copula) is almost completely filled by two complete reproductive tracts comprising the female as well as male organs. Such a reproductive strategy, in which two independent heterogenic individuals fuse into a single hermaphrodite organism without the need to search for mating partner, represents a high specialization of diplozoids to their parasitic life.

Redescription and resurrection of Bertiella satyri (Cestoda, Anoplocephalidae) parasitizing the orangutan (Pongo abelii) in Indonesia.

The tapeworm species Bertiella satyri from a semi-wild Sumatran orangutan (Pongo abelii: Ponginae) is redescribed and the sequence of its 18S rDNA is presented. The tapeworms parasitizing the genera Pan, Pongo, Homo and Hylobates from Muséum National d'Histoire Naturelle, Paris and from Muséum d´Histoire Naturelle, Genève are also presented. The validity of B. satyri is confirmed. B. satyri (BSA) differs from the most similar species Bertiella studeri (BSTU) in the following characteristics: (1) testes number, BSTU 300-400; BSA 116-124, (2) genital opening, BSTU regularly alternate; BSA irregularly alternate, (3) Cirrus-sac, BSTU short, 0.250-0.320, does not reach excretory ducts; BSA long, 0.630 × 0.495, reaches excretory ducts, (4) egg size, BSTU 0.053-0.060; BSA 0.030-0.051, (5) host BSTU Pan troglodytes, Africa; BSA Pongo pygmaeus, P. abelii, Indonesia (Borneo, Sumatra). Both species differ according to our material and the name B. satyri (Blanchard, 1891) is resurrected.

Eudiplozoon nipponicum: morphofunctional adaptations of diplozoid monogeneans for confronting their host.

BACKGROUND: Monogeneans, in general, show a range of unique adaptations to a parasitic lifestyle, making this group enormously diverse. Due to their unique biological properties, diplozoid monogeneans represent an attractive model group for various investigations on diverse biological interactions. However, despite numerous studies, there are still gaps in our knowledge of diplozoid biology and morphofunctional adaptations. RESULTS: In this study, we provide a comprehensive microscopic analysis of systems/structures involved in niche searching, sensing and self-protection against the host environment, and excretory/secretory processes in Eudiplozoon nipponicum. Freeze-etching enabled us to detect syncytium organisational features not visible by TEM alone, such as the presence of a membrane subjacent to the apical plasma membrane (separated by a dense protein layer) and a lack of basal plasma membrane. We located several types of secretory/excretory vesicles and bodies, including those attached to the superficial membranes of the tegument. Giant unicellular glands were seen accumulating predominantly in the apical forebody and hindbody haptor region. Muscle layer organisation differed from that generally described, with the outer circular and inner longitudinal muscles being basket-like interwoven by diagonal muscles with additional perpendicular muscles anchored to the tegument. Abundant muscles within the tegumentary ridges were detected, which presumably assist in fixing the parasite between the gill lamellae. Freeze-etching, alongside transmission electron and confocal microscopy with tubulin labelling, enabled visualisation of the protonephridia and nervous system, including the peripheral network and receptor innervation. Three types of receptor were identified: 1) uniciliated sensory endings with a subtle (or missing) tegumentary rim, 2) obviously raised uniciliated receptors with a prominent tegumentary rim (packed with massive innervation and muscles) and 3) non-ciliated papillae (restricted to the hindbody lateral region). CONCLUSIONS: This study points to specific morphofunctional adaptations that have evolved in diplozoid monogeneans to confront their fish host. We clearly demonstrate that the combination of different microscopic techniques is beneficial and can reveal hidden differences, even in much-studied model organisms such as E. nipponicum.

Architecture of Paradiplozoon homoion: A diplozoid monogenean exhibiting highly-developed equipment for ectoparasitism.

Diplozoidae (Monogenea) are blood-feeding freshwater fish gill ectoparasites with extraordinary body architecture and a unique sexual behaviour in which two larval worms fuse and transform into one functioning individual. In this study, we describe the body organisation of Paradiplozoon homoion adult stage using a combined approach of confocal laser scanning and electron microscopy, with emphasis on the forebody and hindbody. Special attention is given to structures involved in functional adaptation to ectoparasitism, i.e. host searching, attachment and feeding/metabolism. Our observations indicate clear adaptations for blood sucking, with a well-innervated mouth opening surrounded by sensory structures, prominent muscular buccal suckers and a pharynx. The buccal cavity surface is covered with numerous tegumentary digitations that increase the area in contact with host tissue and, subsequently, with its blood. The buccal suckers and the well-innervated haptor (with sclerotised clamps controlled by noticeable musculature) cooperate in attaching to and moving over the host. Putative gland cells accumulate in the region of apical circular structures, pharynx area and in the haptor middle region. Paired club-shaped sacs lying laterally to the pharynx might serve as secretory reservoirs. Furthermore, we were able to visualise the body wall musculature, including peripheral innervation, the distribution of uniciliated sensory structures essential for reception of external environmental information, and flame cells involved in excretion. Our results confirm in detail that P. homoion displays a range of sophisticated adaptations to an ectoparasitic life style, characteristic for diplozoid monogeneans.

Morphometric and molecular characteristics of Labeonema synodontisi n. comb. (Nematoda: Atractidae) from the West African fishes.

Numerous nematodes were found in the rectum of three fish species Synodontis ocellifer, S. nigrita, and S. schall (Mochokidae, Siluriformes) from the Gambia River and Mare Simenti, National Park Niokolo Koba, Senegal. A nematode species Raillietnema synodontisi Vassiliadès, 1973 (host S. ocellifer), is redescribed using morphometric (including scanning electron microscopy) and molecular characteristics and transferred into the genus Labeonema Puylaert, 1970. It is morphologically and metrically similar to Labeonema intermedium Puylaert, 1970, the other congeneric species (L. bainae Baker, 1982; L. bakeri Van Waerebeke, Chabaud, Bain et Georges, 1988; and L. africanum Moravec et Van As, 2004) differ from them either by the spicule and gubernaculum lengths, distribution and number of pre-cloacal papillae, position of the vulva, as well as hosts and geographical distribution. The partial sequences of small ribosomal subunit rDNA of L. synodontisi were analyzed and compared with other nematode sequences. Molecular analyses seem to support the position of this nematode species based on the morphological observation.