Haplorchis taichui is the minute intestinal fluke (MIF), presents a significant public health concern in Thailand. Despite praziquantel (PZQ) being the main treatment, concerns over recurrent use and drug resistance have surfaced. Thus, local herbal alternatives effective against gastrointestinal parasites could be crucial for reducing issues, necessitating exploration of herbal sources for alternative treatments. The objective of this study is to evaluate the efficacy of crude extracts from Allium sativum, Thunbergia laurifolia, and Eurycoma longifolia against H. taichui newly excysted juveniles (NEJ). H. taichui NEJs were exposed to varying concentrations of A. sativum (5, 10, and 20 mg/ml), T. laurifolia, and E. longifolia (100, 200, and 400 mg/ml), alongside PZQ (20 mg/ml) and RPMI culture medium as controls. Motility assessment at different exposure times and morphological surface changes were conducted by scanning electron microscopy (SEM). Treatment with A. sativum, T. laurifolia, and E. longifolia inhibited motility in H. taichui NEJs, resulting in reduced relative motility (RM) values and survival index (SI). Significant differences were noted in A. sativum and E. longifolia treated groups, with T. laurifolia showing no significant differences compared to the negative control. Morphological damage, especially tegumental swelling, was evident across all treatment groups, notably severe in the A. sativum group. These findings suggest the potential effectiveness of crude extracts of A. sativum, T. laurifolia, and E. longifolia against H. taichui NEJs. However, further investigations are necessary to understand their mechanisms and key bioactive compounds for developing effective anti-parasitic agents against helminthic infections.
Sixteen labrid species, including four Bodianus spp., were examined in New Caledonia (South Pacific) and monogeneans were found only on Bodianus perditio (Quoy et Gaimard). This species, Haliotrema banana sp. n., is the second Haliotrema species to be described from the labrids, the first being Haliotrema bodiani Yamaguti, 1968 from Bodianus albotaeniatus (Valenciennes), previously designated as B. bilunulatus (Lacépède). The new species is similar to H. bodiani in soft reproductive parts but differs from it in the morphologies of the hard haptoral parts, mainly in the shape of the dorsal bar (bar-shaped vs V-shaped in H. bodiani) and ventral bar. It is similar to Haliotrema spirale Yamaguti, 1968 and Haliotrema minutospirale Yamaguti, 1968 in the shape of the anchors and bars but differs from them in the detailed structures of the copulatory organ and vaginal system.
This is a catalogue and discussion of the known dactylogyridean monogenean genera of siluriform fishes of the Old World. Of a total of 38 nominal genera, only 19 are considered valid. Seventeen of these 19 genera are currently in the Ancyrocephalidae (containing the Ancyrocephalinae and Ancylodiscoidinae), whilst the other two (Neocalceostoma and Neocalceostomoides) are in the Neocalceostomatidae. The 17 genera are Anchylodiscus, Ancylodiscoides, Bagrobdella, Bifurcohaptor, Bychowskyella, Chauhanellus, Cornudiscoides, Hamatopeduncularia, Mizelleus, Paraquadriacanthus, Pseudancylodiscoides, Protoancylodiscoides, Quadriacanthus, Schilbetrema, Schilbetrematoides, Synodontella and Thaparocleidus. Clariotrema Long, 1981 and Neobychowskyella Ma, Wang & Li, 1983 are considered synonyms of Bychowskyella Akhmerov, 1952, Anacornuatus Dubey, Gupta & Agarwal, 1992 is considered a synonym of Quadriacanthus Paperna, 1961, Mizellebychowskia Gupta & Sachdeva, 1990 is considered a synonym of Neocalceostoma Tripathi, 1959 and Hargitrema Tripathi, 1959 is treated as a synonym of Hamatopeduncularia Yamaguti, 1953. It is proposed that the Ancylodiscoidinae be raised to family status within the order Dactylogyridea to accommodate these 17 'ancyrocephalid' genera from siluriforms, together with Malayanodiscoides and Notopterodiscoides from notopterids. A key and the diagnostic characteristics of the 19 recognised dactylogyridean genera from catfishes plus two from notopterids, together with a list of species and synonyms, are included. New combinations made in this work are Thaparocleidus avicularia (Chen, 1987) n. comb., T. calyciflorus (Chen, 1987) n. comb., T. choanovagina (Luo & Lang, 1981) n. comb., T. dissimilis (Chen, 1988) n. comb., T. leiocassis (Reichenbach-Klinke, 1959) n. comb., T. meticulosa (Chen, 1987) n. comb., T. parasoti (Zhao & Ma, 1999) n. comb., T. persculpus (Chen, 1987) n. comb., T. valga (Chen, 1987) n. comb. and T. wulingensis (Yao & Wang, 1997) n. comb. [all from Silurodiscoides] and Bychowskyella glyptothoraci (Ma, Wang & Li, 1983) n. comb. [from Neobychowskyella].
Twenty-three species of intestinal flukes reported in man in Southeast Asia are assigned to seven families: Echinostomatidae, Fasciolidae, Heterophyidae, Lecithodriidae, Microphallidae, Paramphistomatidae and Plagiorchiidae. The majority of species belongs to the Heterophyidae and Echinostomatidae families. Common species are Fasciolopsis buski, Echinostoma ilocanum, E. malayanum, E. revolutum and Haplorchis yokogawai. The countries where large number of species were reported are Thailand (14 species), Philippines (12 species), Indonesia (8 species) and Malaysia (4 species). Only one species was recognized in Laos, and Vietnam. Several species reported in man in the other regions, were reported in animals in Southeast Asia. It is possible that these are present in humans but have not yet been reported.
Ectoparasites cause serious problems during the aquaculture production of food fishes. In this study, we set out to develop and test protocols for maintenance and sampling European catfish (Silurus glanis L., 1758) stocks infected with a gill monogenean, Thaparocleidus vistulensis (Siwak 1932) Lim 1996. When we compared the feasibility of two cohabitation-based parasite culture systems (i.e., static vs. flow-through), we found that the life cycle of T. vistulensis was completed in both habitats. In our experience, static tank systems with regular water exchange allowed better daily quality control of the parasite culture than continuous flow-through systems. We investigated the microhabitat preference of T. vistulensis on the gills of infected European catfish. A balanced distribution on the two lateral gill sets and a decreasing trend in parasite numbers from anterior gill holobranches towards the posterior ones was observed. Using these results, we developed a minimally invasive sampling protocol to estimate the parasite load of individuals. The biopsy aimed at four sectors (#6, #7, #10, and #11) situated within the distal and middle zones of the first holobranch on the left side, encompassing both rows of filaments. Biopsy-based estimates of parasite loads were validated by comparing them to full parasite counts of the same individuals and showed statistically significant correlations. Our biopsy-based method is designed to identify experimental animals with similar parasite loads and create groups of hosts with comparable burdens. This setup is expected to generate reduced between-group differences for expensive experiments (e.g., high throughput transcriptomic or epigenetic studies). We propose that the biopsy-based pre-sorting procedure should be considered in similar experiments with other cultured fish species and their gill monogeneans following a thorough fine-tuning of the experimental conditions.
We describe Morishitium polonicum malayense n. subsp. from Asian glossy starlings (Aplonis panayensis strigata) (Horsfield, 1821) (Passeriformis: Sturnidae) caught in Malaysia. The trematodes had parasitized the air sacs and the thoracic and body cavities of 40 out of 67 (59.7%) birds examined. The specimens each had an oral sucker, a postpharyngeal genital pore, and tandem testes, but lacked a ventral sucker. The morphological characteristics of our specimens were similar to those of M. polonicum polonicum (Machalska, 1980) from Poland. However, the anterior extremity of vitelline follicles of the present specimens sometimes extended to the level of pharynx. The oral sucker width, oral sucker width/pharynx width ratio, and intertesticular space metrics differed from those of M. p. polonicum. The maximum-likelihood trees based on the cytochrome c oxidase subunit I (COI) and the internal transcribed spacer 2 (ITS2) sequences indicated that the species from the present study formed a sister group with M. p. polonicum from the Czech Republic. The p-distances of COI and ITS2 sequences between the present specimens and M. p. polonicum from the Czech Republic were 6.9-7.5% and 0.6%, respectively. These genetic divergences indicate the border for intra- or interspecific variation of digeneans. The definitive host species and geographical distribution of the current specimens were distinct from those of M. p. polonicum from Europe. We thus concluded that the present specimens are ranked as a new subspecies of M. polonicum, namely M. polonicum malayense n. subsp.
: Baracktrema obamai n. gen., n. sp. infects the lung of geoemydid turtles (black marsh turtle, Siebenrockiella crassicollis [type host] and southeast Asian box turtle, Cuora amboinensis ) in the Malaysian states of Perak, Perlis, and Selangor. Baracktrema and Unicaecum Stunkard, 1925 are the only accepted turtle blood fluke genera having the combination of a single cecum, single testis, oviducal seminal receptacle, and uterine pouch. Baracktrema differs from Unicaecum by having a thread-like body approximately 30-50× longer than wide and post-cecal terminal genitalia. Unicaecum has a body approximately 8-12× longer than wide and terminal genitalia that are anterior to the distal end of the cecum. The new genus further differs from all other accepted turtle blood fluke genera by having a cecum that is highly convoluted for its entire length, a spindle-shaped ovary between the cirrus sac and testis, a uterine pouch that loops around the primary vitelline collecting duct, a Laurer's canal, and a dorsal common genital pore. Phylogenetic analysis of the D1-D3 domains of the nuclear large subunit ribosomal DNA (28S) revealed, with high nodal support and as predicted by morphology, that Baracktrema and Unicaecum share a recent common ancestor and form a clade sister to the freshwater turtle blood flukes of Spirorchis, paraphyletic Spirhapalum, and Vasotrema and that, collectively, these flukes were sister to all other tetrapod blood flukes (Hapalorhynchus + Griphobilharzia plus the marine turtle blood flukes and schistosomes). Pending a forthcoming emended morphological diagnosis of the family, the clade including Spirorchis spp., paraphyletic Spirhapalum, Vasotrema, Baracktrema, and Unicaecum is a likely placeholder for "Spirorchiidae Stunkard, 1921 " (type genus Spirorchis MacCallum, 1918 ; type species Spirorchis innominatus Ward, 1921 ). The present study comprises the 17th blood fluke known to infect geoemydid turtles and the first proposal of a new genus of turtle blood fluke in 21 yr.
Monogeneans identified as Sinodiplectanotrema malayanum n. sp. were collected from the fish Pennahia anea (Sciaenidae) off the west coast of Peninsular Malaysia. The new species is recognised on the basis of morphometrical differences in the anchors, marginal hooks and eggs and apparent differences in the 28S rDNA sequence data. The new species possesses features (ovary looping the intestinal caecum, body spines, a vagina and haptoral reservoirs) not noted in the original description of the type and only other species of the genus, S. argyrosomus Zhang, 2001, necessitating the re-assignment of the genus to the Diplectanidae Monticelli, 1903, a move which is supported by 28S rDNA evidence. Sinodiplectanotrema is redefined on the basis of the observation of several features not included in the original diagnosis.
One new and four previously described species of Triacanthinella Bychowsky & Nagibina, 1968 (Monogenea) were collected from the tripodfishes Triacanthus biaculeatus and Tripodichthys blochii off Peninsular Malaysia. Triacanthinella lumutensis n. sp. from Tripodichthys blochii off Lumut, Selangor is similar to Triacanthinella principalis Bychowsky & Nagibina, 1968 in having morphologically similar types of haptoral sclerites and copulatory organ, but differs in possessing a longer copulatory tube. Also re-described are T. principalis Bychowsky & Nagibina, 1968, T. gracilis Bychowsky & Nagibina, 1968 and T. aspera Bychowsky & Nagibina, 1968 from both Triacanthus biaculeatus and Tripodichthys blochii, plus Triacanthinella longipenis Bychowsky & Nagibina, 1968 from Tripodichthys blochii and Triacanthinella tripathii Bychowsky & Nagibina, 1968 based on its type-material. In the new species, the filament loop of the anchors is associated with a sheath-like sclerite which envelops the anchor point. Such sclerites were also observed in the present specimens of Triacanthinella principalis, T. aspera, T. longipenis and T. gracilis but were not mentioned in the original descriptions. The generic diagnosis of Triacanthinella is amended and a key to the recognised species is presented. The specific names of two of the previously described species are emended from the neuter form to T. principalis and T. gracilis.