A checklist of parasitic cymothoids from Malaysian waters is presented based on available literature and material collected from 2010 to 2020. Most of the collected specimens were recorded from waters of Terengganu, east coast of Peninsular Malaysia (facing the South China Sea), whereas literature records were included from Sarawak, along the Miri coast of northwest Borneo. The checklist comprises 19 species in ten genera, seven of which are new records from Malaysia: Anilocra nemipteri Bruce, 1987; Ceratothoa barracuda Martin, Bruce & Nowak, 2015; Ceratothoa carinata (Bianconi, 1869); Cymothoa epimerica Avdeev, 1979; Elthusa sigani Bruce, 1990; Joryma engraulidis (Barnard, 1936) and Renocila richardsonae Williams & Bunkley-Williams, 1992. Eight new host records are based on collected specimens: Anilocra nemipteri was dorsally attached on Nemipterus nemurus (Bleeker, 1857), Nemipterus nematophorus (Bleeker, 1854), Nemipterus tambuloides (Bleeker, 1853) and Nemipterus thosaporni Russell, 1991 (family Nemipteridae); Ceratothoa carinata was found in the buccal cavity of Decapterus macrosoma Bleeker, 1851 (family Carangidae); Cymothoa eremita (Brunnich, 1783) was attached in the buccal cavity of Nemipterus tambuloides (Bleeker, 1853) and Nemipterus furcosus (Valenciennes, 1830); Elthusa sigani was found attached on the gills of Pterois russelli Bennett, 1831 (family Scorpaenidae), and Renocila richardsonae was attached on the caudal fin of Upeneus japonicus (Houttuyn, 1782) (family Mullidae). All cymothoid species listed here are known to have a Central Indo-Pacific distribution, with some ranging as far as the Western Indian Ocean. A cymothoid-host association is here listed from 28 fish families, with the most commonly reported from Carangidae (pompanos, jack mackerels, runners, scads), Engraulidae (anchovies), and Leiognathidae (ponyfishes, slipmouths). This paper is the first comprehensive review of both verified literature records and deposited specimens. A key for the family of Cymothoidae in Malaysian waters is given.
Raw or undercooked fish dishes are the major sources of human infection of fishborne trematodes (FBT) and the situation of metacercarial infection in fish greatly affect the prevalence in humans, especially those fish that are commonly used for raw consumption. To investigate the situation of infection with metacercaria of FBT in fish often used to prepare raw fish dishes by local people to assess the risk of infection to humans in Ninh Binh province, Vietnam. 345 fish belonging to five species of freshwater and one species of brackish water fish were collected from fishermen or small-scale fish dealers in Kim Son and Yen Khanh districts, Ninh Binh province between May 2017 and May 2018. Metacercaria of FBT was discovered by pepsin and hydrochloric acid digestion techniques and identified by the morphological and molecular analysis. Among examined fish, 44.06% infected with FBT metacercaria and the highest prevalence was in Cyprinus carpio (86.54%), Ctenopharyngodon idellus (78.43%) and Hypophthalmichthys molitrix (66.67%) while Konosirus punctatus - the brackish water fish - were free from infection. Three species of FBT were found; namely Haplorchis pumilio (accounting for 99.84% of collected metacercariae), Haplorchis taichui and Clonorchis sinensis. The average density was 1.06 metacercariae per gram of freshwater fish and the highest number was of C. idellus (6.38 cysts/gram) followed by Cirrhinus molitorella and C. carpio. Results of the study show the high prevalence of infection of FBT metacercariae among freshwater fish often used to prepare raw fish dishes in Ninh Binh province. These findings suggest the need for greater awareness of the risk from raw fish dishes among public health authorities and people.
Epidemiological studies have been conducted to determine the association between fish and disease. The fish were obtained from rivers, streams, ponds and lakes but few from aquaculture farms. While no defined studies have been carried out in Malaysia, baseline data show that fish obtained from aquaculture farms (mixed farming) contributed to cases of opisthorchiasis and clonorchiasis.
A total of 104 marine fish belonging to 12 species in 6 families were examined for anisakid larvae. All except one fish species were infected with one or more types of anisakid larvae. Three types of anisakid larvae were recovered, the most abundant being Anisakis type 1 (9 out of 11 fish species) followed by Contracaecum type B (6 out of 11) and Terranova type B (1 out of 11). Latianus malabaricus has the highest mean intensity of both Anisakis type 1 and Contracaecum type B. The public health hazard of anisakine nematodes is briefly discussed.
Sundatrema langkawiense n. g., n. sp. (Monogenea: Ancyrocephalidae) is described from the gills of the orbfish Ephippus orbis (Bloch) (Ephippidae) off the Island of Langkawi, Malaysia, in the Andaman Sea. This new genus has the ancyrocephalid characteristics of four anchors, 14 marginal hooks and two bars, but differs from other four-anchored monogenean genera, and notably from Parancylodiscoides Caballero & Bravo Hollis, 1961 (found on the ephippids Chaetodipterus spp. off Central and South America), by having a unique combination of features. These include a muscular genital sucker and a vas deferens and vagina on the same (sinistral) side of the body. It is similar to Parancylodiscoides in having four haptoral reservoirs opening at the anchoral apertures, four anchors, similar connecting bars and small marginal hooks. The new species is characterised by the above generic features and by possessing a small, short copulatory organ lacking an accessory piece. Diplectanum longiphallus MacCallum, 1915 (previously attributed to Ancyrocephalus Creplin, 1839, Tetrancistrum Goto & Kikuchi, 1917 and Pseudohaliotrema Yamaguti, 1953) is transferred to Parancylodiscoides as P. longiphallus (MacCallum, 1915) n. comb.
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.
Two new species of the parasitic copepod genus Dissonus Wilson, 1906 are described: D. excavatus n. sp. from the gills of a labrid, Bodianus perditio, and a lutjanid, Macolor niger, collected off New Caledonia and Taiwan, and D. inaequalis n. sp. from a hemiscylliid elasmobranch, Chiloscyllium punctatum, collected off Sarawak (Malaysia) and the Philippines. Material of D. heronensis Kabata, 1966 is described from a balistid host, Pseudobalistes fuscus, off New Caledonia, and this constitutes a new host record for this parasite. D. manteri Kabata, 1966 was collected from four serranid host species off New Caledonia and from one of the same hosts off Taiwan. Two of the hosts from New Caledonia, Plectropomus laevis and Epinephelus cyanopodus, represent new host records. D. pastinum Deets & Dojiri, 1990 was recognised as a new synonym of D. nudiventris Kabata, 1966, so the total number of valid species is now twelve. Material from museum collections of D. nudiventris, D. similis Kabata, 1966 and D. spinifer Wilson, 1906 was re-examined and provided new information which is utilised in a key to all valid species of Dissonus.
Two new and two previously described species of diplectanid monogeneans (Heteroplectanum flabelliforme n. sp., Diplectanum sumpit n. sp., D. jaculator Mizelle & Kritsky, 1969 and D. toxotes Mizelle & Kritsky, 1969) were collected from archerfish Toxotes jaculatrix off the Island of Langkawi, Kedah and off Perak, Malaysia. The reproductive systems and squamodiscs of D. jaculator and D. toxotes are described for the first time. D. sumpit n. sp. differs from D. toxotes and D. jaculator in a having a small curved copulatory tube with a distinct accessory piece, compared to the long, tubular copulatory tube of D. jaculator and the slender tube of D. toxotes. D. sumpit n. sp. also differs from D. toxotes in having a larger ventral bar and larger squamodiscs. H. flabelliforme n. sp. differs from all known Heteroplectanum species in the shape and size of the squamodiscs, the arrangement of the sclerites in the squamodiscs, the extremely large ventral bar and the short, curved, non-spinous copulatory tube.
Four new species of Calydiscoides Young, 1969 are described from three species of nemipterids caught off Kemaman, Terengganu, on the eastern coast of Peninsular Malaysia: C. monogrammae n. sp. from Scolopsis monogramma; C. conus n. sp. from S. magaritifer; C. scolopsidis n. sp. from S. margaritifer and S. monogramma; and C. kemamanensis n. sp. from Pentapodus setosus. The present investigation reveals that the squamodiscs (lamellodiscs) are composed of 10-12 short, complete, interlocking and concentric tubular lamellae. The innermost lamella is attached to a pair of adductor muscles.
Marine leech Zeylanicobdella arugamensis (Piscicolidae), an economically important parasite is infesting predominantly cultured groupers, hybrid groupers and other fish in Southeast Asian countries. In this study, we tested the anti-parasitic potential of a medicinal plant Nephrolepis biserrata found in Sabah, East Malaysia against Z. arugamensis. Various concentrations of methanol extracts of the plant were tested experimentally against Z. arugamensis and disinfestation of the leech from its primary host hybrid groupers. The composition of methanol extract of N. biserrata was determined through LC-QTOF analysis. The significant anti-parasitic activity of 100% mortality of leeches was observed with the exposure of N. biserrata extracts. The average time to kill the leeches at concentrations of 25, 50 and 100 mg/ml was 25.11 ± 3.26, 11.91 ± 0.99, and 4.88 ± 0.50 min., respectively. Further, at various low concentrations of N. biserrata 2.5, 5 and 10 mg/ml, hybrid groupers were disinfested in an average time of 108.33 ± 12.65, 65.83 ± 9.70 and 29.16 ± 5.85 min., respectively. The tandem mass spectrometry data from LC-QTOF indicated some hits on useful bioactive compounds such as terpenoids (ivalin, isovelleral, brassinolide, and eschscholtzxanthin), flavonoids (alnustin, kaempferol 7,4'-dimethyl ether, and pachypodol), phenolics (piscidic acid, chlorogenic acid, and ankorine), and aromatic (3-hydroxycoumarin). Thus N. biserrata can act as a potential biocontrol agent.
Betta rubra is an ornamental freshwater fish endemic to northern Sumatra, Indonesia. The B. rubra population has decreased in recent decades, and is classified as an endangered species in the IUCN Red List. This study aims to report for the first time infection by L. cyprinacea in B. rubra harvested from the Aceh Besar region of Indonesia. The fish samples were obtained from the Cot Bira tributaries, Aceh Besar District, Indonesia from January to December 2020. The results showed that the parasite infected 6 out of 499 samples in August and September, with a prevalence and intensity rate of 1% and 2 parasites/fish, respectively. The eyes and pectoral fins were the common infection sites. Despite B. rubra is not an optimal host (small size) for the parasite, this parasite might serve as additional threatening factors for the endangered B. rubra fish population.
Systematization and description of composition and structure of the monogeneans from the genus Dactylogyrus Diesing, 1850 mostly having five rayed ventral (additional) bar of the haptor and parasitizing mainly Palaearctic Barbinae and Leuciscinae, were carried out. These dactylogyrids have Palaearctic origin and occur in the north-western Africa, central and southern Europe, Transcaucasia, middle Asia, Mesopotamia and also in India and the Malacca Peninsula. Previously the analysis of dactylogyrids' distribution by continents (Gerasev et al., 1996), geographical regions (Gerasev, Timofeeva, 1997), taxonomic groups of hosts (Gerasev, 2008a, 6), and different taxonomic groups of host inside one geographical division (Kolpakov et al., 2007; Gerasev et al., 2007, 2008) was performed. This analysis have not been always resulted in the understanding of conjugate evolution of these parasites and their fish hosts, as well as in the resolving of problems concerned with speciation of monogeneans and phylogeography of their hosts. Therefore, in present work we consider more than one geographical region, different fish taxa, and the morphological groups of worms reflecting morphological variational series of types of copulatory organ and additional bar. Typification of copulatory organ, additional bar, anchors, and type of seating for 11 Palaearctic morphological groups of dactylogyrids mainly having five rayed additional ventral bar, were carried out. Four morphological groups of dactylogyrids of African, Indian, and different Palaearctic origin also parasitizing Palaearctic barbs were additionally included into analysis. In all, 92 species of dctylogyrids from 78 host species were considered. Analysis of speciation and phylogeny of dactylogyrids having five rayed additional ventral bar of haptor; conjugate evolution of these dactylogyrids and their fish hosts (mainly Barbinae); point of origin of Palaearctic polyploids Barbinae, and expansion of these fishes over the territory of Palaearctic will be discussed in next article.
Haliotrema susanae sp. nov. is described from the gills of the pinecone soldierfish, Myripristis murdjan off Langkawi Island, Malaysia. This species is differentiated from other Haliotrema species especially those from holocentrids in having a male copulatory organ with bract-like extensions at the initial of the copulatory tube, grooved dorsal anchors and ventral anchors with longer shafts. The maximum likelihood (ML) analysis based on partial 28S rDNA sequences of H. susanae sp. nov. and 47 closely related monogeneans showed that H. susanae sp. nov. is recovered within a monophyletic clade consisting of only species from the genus Haliotrema. It is also observed that H. susanae sp. nov. forms a clade with H. cromileptis and H. epinepheli which coincides with a similar grouping by Young based on solely morphological characteristics. The morphological and molecular results validate the identity of H. susanae sp. nov. as belonging to the genus Haliotrema.
The Caligidae is a family of parasitic copepods containing over 30 recognised genera. They are commercially important parasites as they cause disease in numerous finfish aquaculture facilities globally. Morphological features are used to distinguish between the genera and Pseudocaligus has traditionally been differentiated from Caligus solely by the presence of a much reduced form of the fourth thoracic leg. Currently there are numerous DNA sequences available for Caligus spp. but only the type species, Pseudocaligus brevipedis, has molecular data available, so systematic studies using molecular phylogenetic analyses have been limited.
Myxosporeans are known from aquatic annelids but parasitism of platyhelminths by myxosporeans has not been widely reported. Hyperparasitism of gill monogeneans by Myxidium giardi has been reported from the European eel and Myxidium-like hyperparasites have also been observed during studies of gill monogeneans from Malaysia and Japan.The present study aimed to collect new hyperparasite material from Malaysia for morphological and molecular descriptions. In addition, PCR screening of host fish was undertaken to determine whether they are also hosts for the myxosporean.
The animal-pathogenic oomycete Saprolegnia parasitica causes serious losses in aquaculture by infecting and killing freshwater fish. Like plant-pathogenic oomycetes, S. parasitica employs similar infection structures and secretes effector proteins that translocate into host cells to manipulate the host. Here, we show that the host-targeting protein SpHtp3 enters fish cells in a pathogen-independent manner. This uptake process is guided by a gp96-like receptor and can be inhibited by supramolecular tweezers. The C-terminus of SpHtp3 (containing the amino acid sequence YKARK), and not the N-terminal RxLR motif, is responsible for the uptake into host cells. Following translocation, SpHtp3 is released from vesicles into the cytoplasm by another host-targeting protein where it degrades nucleic acids. The effector translocation mechanism described here, is potentially also relevant for other pathogen-host interactions as gp96 is found in both animals and plants.
Six species of strigeoid trematodes are reported from Malaysia. One new genus and 3 new species are described: Apatemon (Apatemon( jamesi sp. n (Strigeidae); cercaria Cotylurus sullivani sp. n. (Strigeidae); Neodiplostomum (Neodiplostomum) sp. (Diplostomatidae); Fibricola ramachandrani (Diplostomatidae); Pseudoscolopacitrema otteri gen. n. et sp. n. (Diplostomatidae); and cercaria Cyathocotyle malayi sp. n. (Cyathocotylidae). The life cycles of A. jamesi and C. malayi have also been investigated.
The diversity of monogeneans from Southeast Asia was examined using information from the literature to show their diversity at different taxonomic (subclass, family, genera, species) levels. Knowledge of monogeneans is still incomplete in Southeast Asia and the present numbers of monogeneans are likely an underestimate of what is present on/in aquatic organisms in the region, since so few hosts have been examined. An estimate of the possible numbers of monogeneans that could be present on/in fishes and turtles in Peninsular Malaysia indicates that only 8% of the monogeneans are presently known. Analysis of the available data on monogenean diversity (or species richness) at different taxonomic levels will provide useful information on their distribution patterns. There is an uneven distribution of investigations on this topic and Malayan fauna is considered to be representative of the Southeast Asian fauna. Southeast Asian (Sundaland) monogeneans are related (at the generic level) to the monogenean fauna of South China, India and Africa.
Partial nuclear 28S ribosomal RNA and mitochondrial cytochrome c oxidase subunit I (COI) gene sequences (953 and 385 nucleotides, respectively) of one fish monogenean (outgroup) and six polystome monogeneans (four Polystomoides spp. from the oral cavities and urinary bladders of freshwater turtles in Australia and Malaya, two Neopolystoma spp. from the urinary bladder and conjunctival sac of a freshwater turtle in Australia) were used to examine the question of whether congeneric species infecting different sites in the same host species have speciated in that host by adapting to different sites, or whether species infecting a particular site in one host have given rise to species infecting the same site in different hosts. Results show unequivocally that congeneric species infecting the same site, even of host species belonging to different suborders and occurring on different continents, are more closely related than congeneric species infecting different sites of the same host species. This is interpreted as meaning that speciation has not occurred in one host. Morphological evolution of polystomes has been very slow: few differences between species and even genera have evolved over a period of at least 150 Myr, and this is matched by low substitution rates of nucleotides, and the ambiguous position of species of different genera, depending on whether COI or 28S rDNA sequences are used.