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Fish-borne trematode metacercariae detected in fish commonly used for raw consumption in Ninh Binh Province, Vietnam

Khoa DV, Hoa DT, Anh DN, Van NT, Dung DT, Huong LTT, et al.

Trop Biomed, 2020 Jun 01;37(2):443-451.
PMID: 33612813

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.

Matched MeSH terms: Fishes/parasitology*
[World fauna of Dactylogyrus spp. (Plathelminthes; Monogenea; Dactylogyridae) with five rayed ventral bar of the haptor. 1. Composition and structure]

Gerasev PI

Parazitologia, 2009 Nov-Dec;43(6):478-501.
PMID: 20198967

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.

Matched MeSH terms: Fishes/parasitology*
Fulltext Multiple gene analyses of caligid copepods indicate that the reduction of a thoracic appendage in Pseudocaligus represents convergent evolution

Freeman MA, Anshary H, Ogawa K

Parasit Vectors, 2013;6(1):336.
PMID: 24286135 DOI: 10.1186/1756-3305-6-336

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.

Matched MeSH terms: Fishes/parasitology
Fulltext Myxosporean hyperparasites of gill monogeneans are basal to the multivalvulida

Freeman MA, Shinn AP

Parasit Vectors, 2011;4:220.
PMID: 22115202 DOI: 10.1186/1756-3305-4-220

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.

Matched MeSH terms: Fishes/parasitology*
A revision of the family Dissonidae Kurtz, 1924 (Copepoda: Siphonostomatoida)

Boxshall GA, Lin CL, Ho JS, Ohtsuka S, Venmathi Maran BA, Justine JL

Syst Parasitol, 2008 Jun;70(2):81-106.
PMID: 18427956 DOI: 10.1007/s11230-008-9132-z

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.

Matched MeSH terms: Fishes/parasitology*
Fulltext Two New Genera and Species of the Parasitic Copepod Family Chondracanthidae Milne Edwards, 1840 (Copepoda: Cyclopoida) from Deep-Sea Fishes Off Suruga Bay, Japan

Aneesh PT, Ohtsuka S, Kondo Y, Helna AK

Acta Parasitol, 2024 Mar;69(1):874-888.
PMID: 38468018 DOI: 10.1007/s11686-024-00820-3

PURPOSE: The present paper describes two new genera and species of the parasitic copepod family Chondracanthidae Milne Edwards, 1840 based on specimens collected from two species of deep-sea fishes at a depth of 212 m off Suruga Bay, Japan. Avatar nishidai gen. et sp. nov. is described from the host fish Chaunax abei Le Danois, 1978 (Chaunacidae). Kokeshioides surugaensis gen. et sp. nov. is described from the host fish Setarches longimanus (Alcock, 1894) (Setarchidae).
METHODS: Fresh specimens of chondracanthids were collected from the buccal cavity of two species of deep-sea fishes (fish hosts were frozen), Chaunax abei Le Danois, 1978 (Lophiiformes: Chaunacidae) and Setarches longimanus (Alcock, 1894) (Perciformes: Setarchidae), caught at a depth of 212 m in Suruga Bay, Japan (34° 37'48.87″ N, 138° 43'2.958″ E). Both the species are described and illustrated based on ovigerous females.
RESULTS: The genus Avatar gen. nov. can readily be distinguished from all other chondracanthid genera by the following combination of features: cephalothorax slightly wider than long with anterior pair of large and posterior pair of small lateral lobes, and two pairs of ventro-lateral processes; the very posteriormost part of the first pedigerous somite contributes to the neck; cylindrical trunk with two pairs of blunt proximal fusiform processes; antennule with small knob terminally; antenna bearing distal endopodal segment; labrum protruding ventrally; two pairs of biramous legs each with 2-segmented rami. Kokeshioides gen. nov. has the following combinations of features that distinguish it from other chondracanthid genera: body flattened, without lateral processes; cephalothorax much wider than long, with paired anterolateral and posterolateral lobes, folded ventrally; the very posteriormost part of the first pedigerous somite contributes to the neck; mandible elongate; legs unique, heavily sclerotized, represented by two pairs of acutely pointed processes.
CONCLUSION: With the addition of two new genera presently reported, the family Chondracanthidae currently includes 52 valid genera. Among the described genera Avatar gen. nov. seems to be very primitive, while Kokeshioides gen. nov. is highly advanced. The deduced evolutionary history of chondracanthid genera is also discussed.

Matched MeSH terms: Fishes/parasitology