New records of three commercial fish hosts for two Unicapsula spp. and Kudoa megacapsula (Myxozoa: Myxosporea: Multivalvulida).

Infections caused by multivalvulid myxosporeans belonging to genera Unicapsula and Kudoa (Cnidaria: Myxozoa) occasionally affect commercial marine fish species. Postmortem myoliquefaction caused by a variety of Kudoa spp., including K. thyrsites, and unsightly cyst or pseudocyst formation, caused by K. amamiensis, U. muscularis, and other kudoid species, negatively affect commercial values of fillets. However, multivalvulid infections are often latent and imperceptible in the market. Biodiversity, host range, and epidemiology remain to be explored. Here, myxosporean infection was detected in four commercial fish species from southern China, using morphological and molecular analyses. Three Unicapsula spp. (U. pyramidata in Nemipterus japonicus; U. pflugfelderi in Dentex angolensis transported from the Eastern Central Atlantic Ocean, off West African coast; and U. aequilobata in Decapterus macarellus) and Kudoa megacapsula in Nemipterus virgatus were observed to form pseudocysts in the myofibers of the host trunk muscles. All fish hosts identified here, except for U. pyramidata, are new records. Kudoa megacapsula was morphologically characterized by gigantic, cruciform myxospores with four wing-like shell valves morphologically comparable to previous Japanese records of the same species in aquaculture facilities, acquiring fly from China or Korea (Sphyraena pinguis and Seriola quinqueradiata, respectively). Molecular analyses established the conspecificity of the present Chinese isolate with previously recorded Japanese isolates. To our knowledge, for the first time, a partial large subunit ribosomal RNA gene sequence of K. megacapsula was obtained, showing close phylogenetic relationships with Kudoa spp. harboring cruciform myxospores, such as K. thyrsites, K. gunterae, K. whippsi, and K. lateolabracis.

Myxidium shedkoae Sokolov, 2013 (Myxozoa: Myxidiidae), a parasite of the gallbladder of Perccottus glenii Dybowski, 1877 (Actinoptrygii: Odontobutidae): Supplementary data on morphology and phylogenetic position based on 18s rDNA sequence analysis.

This paper is the first report on the molecular characterisation of myxozoan parasites from the odontobutid fish Chinese (Amur) sleeper (Perccottus glenii Dybowski, 1877). The authors determined the partial 18S rDNA sequence of Myxidium shedkoae Sokolov, 2013 from the gallbladder of the fish. Phylogenies reconstructed using maximum likelihood and Bayesian inference analysis revealed that M. shedkoae belongs to the hepatic biliary group of myxozoans (after Kristmundsson and Freeman, 2013) as a member of the clade consisting of Zschokkella sp. KLT-2014, Myxidium truttae and Zschokkella nova. Some new morphological features of the parasite are also presented.

Myxobolus arcticus and Parvicapsula minibicornis infections in sockeye salmon Oncorhynchus nerka following downstream migration in British Columbia.

Factors influencing the health of sockeye salmon Oncorhynchus nerka in British Columbia, Canada, are important for fisheries management and conservation. Juvenile salmon originating from the Fraser River were screened for 3 enzootic parasites (Myxobolus arcticus, Parvicapsula minibicornis, Ceratonova shasta) and the bacterium Renibacterium salmoninarum. Fish were collected from the Strait of Georgia in 2010, 2011 and 2012 and genotyped to stock of origin. Trends in infection status were estimated by year, spawning zone and catch area. The annual prevalences of P. minibicornis (n = 1448) were 23.3, 6.5 and 8.1%, and for M. arcticus (n = 1343), annual prevalences were 40.4, 66.3 and 27.4%, respectively. Logistic regression showed that P. minibicornis was most strongly associated with salmon from the lower Fraser River spawning zone and increased with distance caught from the mouth of the Fraser River. In contrast, infection with M. arcticus was most strongly associated with salmon from the middle Fraser River spawning zone, and there was no trend related to distance from the Fraser River. Neither R. salmoninarum nor C. shasta were detected. These observations are discussed in the context of salmon life history and pathogen biology.

Two novel myxosporean species (Myxosporea: Bivalvulida), Myxobolus marumotoi n. sp. and Cardimyxobolus japonensis n. sp., from the dark sleeper, Odontobutis obscura, in Japan.

Two new myxosporean species, Myxobolus marumotoi n. sp. and Cardimyxobolus japonensis n. sp. (Myxozoa: Myxosporea: Bivalvulida), are described from the dark sleeper, Odontobutis obscura, in Japan, based on their morphological and molecular characterizations. Plasmodia of M. marumotoi n. sp. (Myxobolidae) grew in the myofiber of trunk muscles, forming pseudocysts. The rounded spore was relatively large, measuring 13.3-15.0 µm (average 13.8) in length, 14.2-15.0 µm (14.6) in width, and 10.0-11.7 µm (10.8) in thickness, with two subspherical polar capsules of 7.9-9.6 µm (8.4) in length by 5.4-6.3 µm (5.9) in width (n = 15). The polar capsules were directed toward the apex of the spore, packing five to six spirals of the polar filament. Plasmodia of C. japonensis n. sp. (Ortholineidae) were surrounded by thin fibrous tissue, forming cysts in the lamina propria of the alimentary tract. The spore was ovoid, wider than long, in valvular view and spindle-shaped in sutural view. It measured 8.8-10.4 µm (9.4) in length, 11.3-12.5 µm (11.9) in width, and 5.2-6.7 µm (5.8) in thickness, with two ovoid polar capsules of 4.2-5.0 µm (4.7) in length by 2.9-3.8 µm (3.3) in width (n = 15). The shell valves of spores often showed a flattened anterior border and semicircular posterior border, and the two polar capsules were directed toward opposite lateral sides. In addition, the sporoplasm contained an iodinophilous vacuole. Almost complete small-subunit (SSU) rDNA sequences, except for primer flanking regions, were obtained for both species; 1,996 bp long for the former and 1,588 bp long for the latter. On phylogenetic trees based on the SSU rDNA sequences of representative species of Bivalvulida, M. marumotoi n. sp. and C. japonensis n. sp. formed a distinct branch in the Henneguya/Myxobolus clade or near but outside this clade, respectively. This study is the first report of the genetic characterization for the genus Cardimyxobolus.

[New data on parasite fauna of the Chinese sleeper Perccottus glenii (Actinopterygii: Odontobutidae) in Primorsky Territory with the description of a new myxozoan species from the genus Myxidium (Myxozoa: Myxidiidae)].

Examination of 116 individuals of Perccottus glenii from water bodies of Primorsky Territory of Russia (the Khanka Lake basin and the Peter the Great Bay basin) revealed the presence of 35 species/taxa of parasites. We give a description of a new species, Myxidium shedkoae sp. nov. Spherical plasmodoa of M. shedkoa sp. nov. are located in the gall bladder; spores are fusiform, with protrusive, pointed, or truncated-cone-shaped poles. The length of spores constitutes 12.6-14.9 (13.4) microm; width, 7.1-8.6 (7.9) microm; shell valves possess 8-10 ridges forming "papillary" pattern. Drawings and descriptions of parasites species poorly studied and recorded from Russia for the first time are given together with drawings and descriptions of some parasites determined only as genera: Triangula perccotti, Gyrodactylus sp., Phyllodistomum sp., Paracoenogonimus ussuriensis (metacercaria), Cyathocotylidae gen. sp. (metacercaria) and Spiroxys japonicus (third-stage juvenile). Parasite fauna of P. glenii in Primorsky Territory comprises 66% of species/forms known for P. glenii in the native part of its range.

Four carangid fish species as new host records for Kudoa trachuri Matsukane, Sato, Tanaka, Kamata et Sugita-Konishi, 2011 (Myxozoa: Multivalvulida), and description of a new species, Kudoa longichorda sp. n., forming pseudocysts in the muscle of Decapterus tabl Berry.

Multivalvulid myxosporeans of the genera Kudoa Meglitsch, 1947 and Unicapsula Davis, 1924 (Cnidaria: Myxozoa) are often the cause of unsightly cyst formation or postmortem myoliquefaction in the trunk muscle of commercial marine fish, which reduces the market value of infected individuals. Twenty species (18 Kudoa spp. and two Unicapsula spp.) have been recorded from carangid fish, although the majority of them, excluding polyxenous species, such as K. amamiensis Egusa et Nakajima, 1980, K. iwatai Egusa et Shiomitsu, 1983, K. nova Naidenova, 1975, K. quadratum (Thélohan, 1895) and K. yasunagai (Hsieh et Chen, 1984), are limited to a single or a few fish species. We report the occurrence of macroscopic cysts of Kudoa trachuri Matsukane, Sato, Tanaka, Kamata et Sugita-Konishi, 2011 in the trunk muscle of four new host fish species, i.e., Pseudocaranx dentex (Bloch et Schneider), Decapterus akaadsi Abe, D. muroadsi (Temminck et Schlegel) and Decapterus tabl Berry, fished from the Philippine Sea (Northwest Pacific Ocean), off southwestern of Japan. Myxospore morphology and genetic characteristics of the ribosomal RNA gene (rDNA) of these isolates were consistent with previous records of K. trachuri from Trachurus japonicus (Temminck et Schlegel) from around Japan. In addition, a new species of Kudoa that forms long filamentous pseudocysts in trunk myofibres was found in four of the six D. tabl collected in this study. We describe Kudoa longichorda sp. n. for this new isolate, based on its morphology of subquadrate myxospores with four shell valves and polar capsules and with small dimensions (length 4.3-5.5 µm, width 6.0-6.8 µm, thickness 4.8-6.3 µm, polar capsule length 2.3-3.1 µm, polar capsule width 1.1-1.7 µm), as well as 18S and 28S rDNA sequences distinct from those of known species.

Xenoma-like formations induced by Soricimyxum fegati (Myxosporea) in three species of shrews (Soricomorpha: Soricidae), including records of new hosts.

In South Bohemia, Czech Republic, 178 shrews, including 98 common shrews, Sorex araneus L., 70 pygmy shrews, Sorex minutus L., and 10 lesser white-toothed shrews, Crocidura suaveolens (Pallas), were examined for Soricimyxum fegati Prunescu, Prunescu, Pucek et Lom, 2007 infections, using squash preparations of unfixed tissues, histological sections and molecular methods. The infection was found in 51 (52%) S. araneus, 14 (20%) S. minutus and 1 (10%) C. suaveolens. The records of the latter two species extend host range of S. fegati. Lesions associated with S. fegati infections in the liver, the organ of specific localisation of the parasite, were found to be induced by proliferative stages migrating toward lumina of bile ducts. In other organs of these three host species, xenoma-like formations (XLFs) were found that severely injured blood vessels. XLFs contained presporogonic stages of S. fegati, whose species identity was evidenced using molecular methods.

Hemagglutination in gill capillaries of sheepshead, Archosargus probatocephalus (Perciformes: Sparidae), infected by a myxosporidean / Hemaglutinação em capilares branquiais de sargo-de-dente, Archosargus probatocephalus (Perciformes: Sparidae) infectado por um mixosporídeo

Abstract During a survey Myxozoa, four specimens of the sheepshead (18 ± 1.5 cm and 59 ± 2.5 g) (Archosargus probatocephalus) were collected in the Ipioquinha river (Maceió/AL). Transmission electron microscopy observations revealed erythrocyte agglutinations in gill capillaries located near spherical cysts containing myxospores of the genus Henneguya. This hemagglutination partially or totally obstructed the gill capillaries. Erythrocytes occurred in close adherence to each other, with a closed intercellular space. A few lysed erythrocytes were observed among agglutinated cells. The reduced lumen of the capillaries was partially filled with amorphous dense homogenous material adhering to the erythrocytes. In addition, heterogeneous masses of irregular lower electron density were observed in the reduced channel of the capillary. The agglutinated erythrocytes appeared dense and homogenous, lacking cytoplasmic organelles. The nuclei had the appearance of normal condensed chromatin masses, generally without visible nucleoli. This occurrence of hemagglutination only in the capillaries located in close proximity to the developing myxozoan cysts suggests that parasite development may be a factor triggering erythrocyte agglutination. This is supported by previous experimental studies that showed a probable correlation between parasitic infections and hemagglutination. Nonetheless, further studies are necessary in order to better understand the physicochemical processes involved in this phenomenon.

Resumo Durante pesquisa de mixozoários foram coletados quatro espécimes do peixes sargo-de-dente (18 ± 1.5 cm e 59 ± 2.5 g) (Archosargus probatocephalus), no rio Ipioquinha (Maceió/AL). Observações por microscopia eletrônica de transmissão revelaram aglutinação de eritrócitos em capilares branquiais localizados próximos a cistos esféricos, contendo mixosporos do gênero Henneguya. Essa hemaglutinação obstruiu parcial ou totalmente os capilares branquiais. Os eritrócitos apareceram em forte aderência entre si, com espaço intercelular fechado. Foram observados poucos eritrócitos lisados entre as células aglutinadas. O lúmen reduzido dos capilares foi parcialmente preenchido com material homogêneo denso amorfo aderido aos eritrócitos, além de massas livres heterogêneas de densidade eletrônica baixa e irregular observadas no canal reduzido dos capilares. Os eritrócitos aglutinados pareciam densos e homogêneos, sem organelas citoplasmáticas. Os núcleos apareceram como massas normais de cromatina condensada, geralmente sem nucléolos visíveis. A ocorrência de hemaglutinação apenas nos capilares, localizados nas proximidades dos cistos mixozoários, sugere que o desenvolvimento parasitário pode ser um fator desencadeante da aglutinação eritrocitária. Isso é corroborado por estudos experimentais anteriores que mostraram uma provável correlação entre infecções parasitárias e hemaglutinação. No entanto, novos estudos são necessários para melhor compreender os processos físico-químicos envolvidos neste fenômeno.

Morphological and molecular characterization of Thelohanellus macrovacuolaris n. sp. (Myxosporea: Bivalvulida) infecting the palate in the mouth of common carp Cyprinus carpio L. in China.

Thelohanellus macrovacuolaris n. sp. is described during a survey on myxozoan diversity of common carp Cyprinus carpio L. in China. It is characterized by the presence of round or ellipsoidal plasmodium in the palate in the mouth of host. Mature spores were pyriform in frontal view, lemon shaped in lateral view, measuring 21.6±0.9 (19.3-23.8) long, 12.5±0.7 (10.3-13.6) wide, and 10.2±0.4 (9.8-11.8) thick. Most spores were surrounded by the membrane sheath. Single polar capsule was round with an apophysis at its top end presented close to apex of spore, measuring 9.1±0.6 (8.0-10.0) in length, 8.6±0.5 (7.8-9.6) in width. Polar filaments coiled, with 7 to 8 turns. A large, round iodinophilous vacuole was present, with 5.8-7.5 in diameter. The present species is morphologically distinct from all other Thelohanellus species. The BLAST search indicated that the newly obtained small subunit ribosomal RNA (ssrRNA) gene sequence of T. macrovacuolaris n. sp. did not match any available sequences in GenBank. Phylogenetically, T. macrovacuolaris n. sp. was placed sister to Thelohanellus wangi in the Thelohanellus clade. Both morphology and ssrRNA gene sequence data revealed that the present parasite is a new species of genus Thelohanellus.

First report of Kudoa sp. in the palate and pharyngeal musculature of Gobioides grahamae Palmer and Wheeler, 1955 (Perciformes, Gobiidae) from Marajó Island, Brazil / Primeiro registro de Kudoa sp. na musculatura do palato e faringeal de Gobioides grahamae Palmer e Wheeler, 1955 (Perciformes, Gobiidae) da Ilha do Marajó, Brasil

The aim of this study was to describe the first occurrence ofKudoasp. inGobioides grahamae, contributing to the understanding of this group of parasites in the Amazonian ichthyofauna. Forty specimens ofG. grahamaecollected from the natural environment were analyzed. Cysts ofKudoasp. were diffusely distributed through the striated skeletal muscle fibers with severe edema and inflammatory infiltrate composed of lymphocytes were observed in 30% of the specimens. Edema and marked coagulation necrosis of the muscle fibers was associated with infection byKudoasp. spores, which had accumulated inside the skeletal muscle fibers. Although there are no records of foodborne outbreaks caused by Kudoa spp. in Brazil, it is of paramount importance that we evaluate its occurrence, since the consumption of fish, especially raw fish, has increased because of the adoption of Japanese cuisine. To minimize the economic impacts on the fisheries market and the risk of this parasite to public health, it is necessary to initiate a program to monitor the presence of this likely underdiagnosed, emerging parasite.(AU)

O objetivo deste estudo foi descrever a primeira ocorrência de Kudoa sp. em Gobioides grahamae, contribuindo, assim, para a compreensão desse grupo de parasitas na ictiofauna amazônica. Foram analisados 40 espécimes de G. grahamae coletados de ambiente natural. Cistos de Kudoa sp. foram distribuídos difusamente através das fibras musculares esqueléticas estriadas com presença de edema grave e infiltrado inflamatório composto de linfócitos, que foram observados em 30% dos espécimes. Edema e necrose de coagulação acentuada das fibras musculares foram associados com a infecção por esporos de Kudoa sp., acumulados no interior das fibras musculares da faringe. Apesar de não haver registros de surtos de origem alimentar causada por Kudoa spp. no Brasil, é de suma importância a avaliação de sua ocorrência, uma vez que o consumo de peixe, especialmente peixe cru, aumentou por causa da adoção da culinária japonesa. Para minimizar os impactos econômicos no mercado da pesca e o risco desse parasita para a saúde pública, é necessário iniciar um programa para monitorar a presença desse parasita emergente, possivelmente subdiagnosticada.(AU)