New Myxozoan Species Research Articles

Morphological and molecular analysis of Henneguya lagunensis n. sp. (Cnidaria, Myxosporea) parasitizing the gills of Eugerres brasilianus from Brazil.

Plasmodia containing myxospores belonging to the genus Henneguya Thélohan, 1892 were found in the gills of Eugerres brasilianus (Cuvier, 1830). Despite the economic importance, few parasitological studies have been done with this species. We describe Henneguya lagunensis n. sp. using morphological and molecular data. The mature myxospores were rounded, measuring 29.1±2.2μm in total length, 8.2±1.0μm in body length, 7.9±0.2μm in body width, 20.7±2.4μm in tail length and 4.8±1.0μm in thickness. The polar capsules measured 3.3±0.4 in length and 1.7±0.3μm in width. Polar filaments had 4-5 turns, helical. Phylogenetic analysis showed Henneguya lagunensis n. sp. as a sister species of Henneguya cynoscioni Dyková, Buron, Roumillat and Fiala, 2011, within a clade that contained mostly Henneguya species that parasitize marine fish of the order Perciformes. This is the first report of a species of Henneguya parasitizing Eugerres brasilianus.

Molecular Phylogeny and taxonomy of a new Myxobolus species from the endangered ornamental fish, Otocinclus cocama endemic to Peru: A host-parasite coextinction approach

A new Myxobolus species is described infecting gill filaments of the endangered ornamental fish Otocinclus cocama from Peruvian Amazon. In a total of 35 fish examined, five (14.3%) had myxozoan plasmodia. Taxonomic analysis was performed integrating multiple characters, including morphometrical, biological traits, ssrDNA sequence data and host ecological characters. Myxospores of M. iquitoensis n. sp. were ovoid in shape from the frontal view and measured 17.6±1.2 µm (16.2–19.8 µm) in length and 10.5±0.7 µm (9.8–12 µm) in width. The two polar capsules were elongate in shape, equal in size and occupying almost half of the myxospore body. They measured 8.7±0.4 µm (6.9–9.3 µm) in length and 3.3±0.2 µm (3–3.6 µm) in width. The polar tubules presented six to seven turns. Molecular phylogenetic analysis revealed that the obtained ssrDNA sequence did not match any existing sequences in GenBank but showed M. iquitoensis n. sp. to be a close species of M. figueirae. Nonetheless, the ssrDNA sequences of those species show large genetic divergence. This is the first description and phylogenetic study of a myxozoan parasitizing fish of the genus Otocinclus from South America, as well the first report of these parasites infecting a fish belonging to the Loricariidae family from Amazon basin. Considering the endangered status of the host, the high degree of host-specificity of freshwater histozoic myxobolids, the low occurrence shown by the new myxozoan, and the fact that this is the only host known for this myxozoan, the conservation status of the new species of myxozoan is likely to be connected to the future survival of its host.

Molecular and morphological analysis of Henneguya jundiai n. sp. (Cnidaria: Myxosporea), a new parasite of the gills of Rhamdia quelen in Brazil

Plasmodia containing spores of a new species of myxozoan, Henneguya jundiai n. sp., were found in the gill arches of Rhamdia quelen catfish. The present study describes H. jundiai n. sp. based on morphological and molecular analysis. The mature spores were elongated and measured 26.9 ± 1.9 (22.9–29.2) μm in total spore length, 9.5 ± 0.4 (8.8–10.0) μm in spore body length, 4.6 ± 0.4 (4.1–5.5) μm in spore body width, 17.3 ± 1.8 (14.1–19.8) μm in tail length, 4.9 ± 0.3 (4.6–5.5) μm in polar capsule length and 1.4 ± 0.2 (1.2–1.7) μm in polar capsule width. The polar filaments had 6–7 coils. Histological analysis revealed the formation of a large plasmodium connected to the gill arch through the epithelial tissue. Ultrastructural analysis revealed the presence of a binucleated sporoplasm, as well as the polar capsules and the coils of the polar filament. Phylogenetic analysis found that H. jundiai n. sp. is located within a subclade formed by species of Henneguya which parasitize siluriform fish from Brazil. Henneguya jundiai n. sp. appears as a sister species of H. quelen. The results of the analyzes clearly indicated the existence of a new species, H. jundiai.

Morphological and Molecular Characteristics of Kudoa viseuensis n. sp. (Myxosporea: Multivalvulida), Found in the Muscle of Batrachoides surinamensis (Teleostei: Batrachoididae) in the Brazilian Amazon Region

A new species of myxozoan, Kudoa viseuensis n. sp. (Myxosporea: Multivalvulida), is described based on specimens extracted from the musculature of the Pacuma toadfish, Batrachoides surinamensis, collected in the municipality of Viseu, in the northern Brazilian state of Para. A total of 60 specimens of B. surinamensis were examined, of which 52 (86%) presented whitish pseudocysts containing numerous rounded spores (7.2±0.2 μm in length and 5.2±0.2 μm in width). These spores have four polar capsules of equal size, measuring 1.8±0.2 μm x 1.3±0.1 μm in the apical view, and 2.7±0.2 μm x 1.3±0.1 μm in the lateral view. A partial sequence (1400 bps) of the small subunit ribosomal RNA gene was obtained and deposited in GenBank (access number: MK256272). The comparison of the morphological and molecular data with those of other Kudoa species supported the description of a new species of mixosporean from the Amazon region, which is denominated here as Kudoa viseuensis n. sp.

Morphological features and molecular phylogeny of Hoferellus azevedoi n. sp. (Myxozoa: Myxobilatidae) found in Chaetobranchus flavescens Heckel, 1840 (Teleostei: Cichlidae) from Marajó Island, northern Brazil.

Hoferellus azevedoi n. sp. was found in the urinary bladder of Chaetobranchus flavescens Heckel, 1840 from the Arari River on Marajó Island in Pará, Brazil. This is the first record of a species of the genus Hoferellus in a host from the Brazilian Amazon region. The new species has disporous and polysporous plasmodia, which vary in size and shape, with some being found adhered to the epithelium of the urinary bladder, and others floating in the liquid. The mature spores are sub-spherical in the sutural view, with a number of peripheral projections around the whole surface of the spore. In the sutural view, the spores are 5.3±0.2 (5.2-5.6) μm in length and 7.0±0.7 (6.3-7.7) μm in width, with two piriform polar capsules of equal size, 2.5±0.2 (2.3-2.8) μm long and 1.8±0.2 (1.6-2.0) μm wide. Based on a partial (1312bps) sequence of the SSU rDNA gene, Hoferellus azevedoi n. sp. was distinguished from all the other myxozoan species deposited in GenBank. Phylogenetically, based on Bayesian inference and p-distances, the new species was allocated to the "Freshwater Urinary-Bladder" clade, together with other myxozoan parasites of the excretory system. Based on the morphological data, supported by the partial sequence of the SSU rDNA gene, we describe a new species of myxozoan, Hoferellus azevedoi n. sp.

Morphological and ssrDNA sequence based molecular characterization of a novel Thelohanellus species (Myxosporea: Myxobolidae) infecting the fins of Goldfish, Carassius auratus L. with special reference to its histopathological alteration

A new species of myxozoan, Thelohanellus goldi n. sp. is described using morphological and molecular data, parasitizing the fin filaments from 18 of 25 host specimens (72.5%) of Carassius auratus collected from different ornamental fish farms of India. Mature spore of the new species were oval to spherical in frontal view having rounded posterior ends and tapering anterior end measures 8.7–10.26 (9.50) × 4.10–7.89 (5.84) μm. The single large polar capsule, round to oval in shape but slightly pointed at the anterior end measuring 4.91–7.63 (5.60) × 2.3–3.1 (2.96) μm and located just below the anterior end of the spore. Polar filament only at distal end with 5–6 loose coils. The most differentiating feature from closely related species was carried out by morpho-taxonomic affinities with previously described species which are tremendously supported by molecular taxonomy by partial sequencing of the 18S rDNA gene resulted in a total of 2124 bp fragment of newly obtained small subunit ribosomal RNA gene sequence of the new species which Exhibit 93–95% homogeneity with other closely related species available in GenBank. The BLAST search and high genetic diversity of distance matrix of Myxobolus sp. did not properly match with any available sequences in GenBank and make sister clade with Thelohanellus caudatus and Thelohanellus habibpuri in the Thelohanellus clade including most of Thelohanellus spp. The study of evolutionary history enables us to understand the evolution of modern species and supports some uncertain topologies which are being presented regarding the morphometric analysis. The severity of myxozoan infection has been assessed in this article by observing the histopathological changes of fins of the C. auratus along with the diversity, distribution and taxonomic description of the new Thelohanellus species with their new host and locality records.

Myxobolus imparfinis n. sp. (Myxozoa: Myxosporea), a new gill parasite of Imparfinis mirini Haseman (Siluriformes: Heptapteridae) in Brazil.

A new species of myxozoan, Myxobolus imparfinis n. sp. is described based on material from the gills of Imparfinis mirini (Haseman) (Heptapteridae). Mature myxospores are round, measuring 7.1-8.4 (7.9 ± 0.3) μm in length, 4.5-6.2 (5.5 ± 0.5) μm in width and 3.1-4.2 (3.7 ± 0.3) μm in thickness. The polar capsules are of unequal size, the larger polar capsule measuring 3.4-4.5 (3.9 ± 0.3) μm in length and 1.4-2.0 (1.7 ± 0.1) μm in width and the smaller capsule measuring 3.1-3.8 (3.4 ± 0.2) μm in length and 1.2-1.8 (1.5 ± 0.2) μm in width. The polar filament presents 6-7 coils. Spores had a prevalence of infection of 75% (6/8). In histological analyses we detected the development site of spores in primary filaments, in afferent branchial artery, thus classifying the type of infection to the filamental type and vascular subtype. The phylogenetic analyses of a dataset including species Myxobolus Bütschli, 1882 and Henneguya Thélohan, 1892 from South America recovered M. imparfinis n. sp. as a sister species of Myxobolus flavus Carriero, Adriano, Silva, Ceccarelli & Maia, 2013. To our knowledge, this is the first record of a myxozoan species parasitising I. mirini.

Henneguya melini n. sp. (Myxosporea: Myxobolidae), a parasite of Corydoras melini (Teleostei: Siluriformes) in the Amazon region: morphological and ultrastructural aspects.

A new species of myxozoan, Henneguya melini sp. n. (Myxosporea: Myxobolidae), was described based on morphologic and ultrastructural features. This is a parasite of the ornamental freshwater fish C. melini from the Rio Negro, and it was found in five of 30 (16.7%) C. melini examined. The parasite was found in the gill filaments, and the plasmodia had form of round to ellipsoid, with mature and immature spores inside them. The average spore body was 15.5 ± 0.2μm in length, 4.7 ± 0.1μm in width, and the tail measured 25.3 ± 0.1μm in length. The spores showed typical features of the genus Henneguya, with two valves of equal size and two symmetrical polar capsules of 4.8 ± 0.7μm in length and 1.7 ± 0.3μm in width. Each polar capsule had a polar filament with five to six turns. Based on morphology (morphologic and ultrastructural data) of the plasmodia and spores and the fact that this is the first report of a Henneguya species in a fish species of the genus Corydoras, it was considered a new myxozoan species.

Henneguya sp. in yellowfin goby Acanthogobius flavimanus from the San Francisco Estuary.

Myxozoan spores were observed in yellowfin goby Acanthogobius flavimanus collected from Suisun Marsh, San Francisco Estuary (SFE). Although histopathological changes associated with the parasite were not observed, the spores formed plasmodia that partially blocked the gastric and intestinal mucosa and gut lumen and may affect the perfomance and survival of the yellowfin goby. Morphological features of the spores resembled Henneguya sp. and molecular analysis of the 18S ribosomal DNA (Domain III) confirmed close similarity to H. rhinogobii and H. pseudorhinogobii isolated from the Japanese freshwater goby. The yellowfin goby myxozoan however, is likely an undescribed species based on phylogenetic analysis and morphologic features. Detailed description of vegetative and spore stages are currently lacking for proposal to a new species of Henneguya. A specific PCR test was developed, which confirmed a 100% prevalence of the parasite among randomly collected gobies in group 1 (N = 30) and group 2 (N = 15) at termination of the study at one month in captivity. The myxozoan was also detected from 18 gobies (12%) that died in the first group within two weeks in captivity. Apparently healthy gobies that served as controls did not reveal the presence of the myxozoan by PCR. This study documents the occurrence of a potentially new species of myxozoan in the yellowfin goby and underscores the detection of a parasitic infection in an introduced fish in the SFE. Although the pathogenesis of the myxozoan was not assessed and the prevalence as reported here is restricted to a comparatively small collection site in Suisun slough, the reemergence, identification, and ecological relevance of the parasite on goby populations in the SFE may be investigated in the future using the specific diagnostic tool developed in this study.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-420) contains supplementary material, which is available to authorized users.

Observations on two new species of Myxobolus Butschli, 1882 from minor carps of Tripura, India

Tripura is a north-eastern state of India with a total geographical area of 10,491sq.km. Labeo bata, L. calbasu, L. gonius of the genus Labeo Cuvier and Cirrhinus reba of genus Cirrhinus Oken are the most popular and commercially important native minor carps of the state. During a detailed survey on the protozoan parasites of the minor carps of Tripura, two new species of myxozoan (Myxozoa: Bivalvulida) parasites Myxobolus tripurensis sp.n. and Myxobolus potularis sp.n. were encountered on the gill filaments of the host fishes. Distinctive characteristics of the plasmodia and the spores have been described.

Henneguya mauritaniensis n. sp. (Myxozoa) from the arterial bulb of Pagrus caeruleostictus (Valenciennes, 1830) off Mauritania

We describe a new species of myxozoan, Henneguya mauritaniensis n. sp., extracted from the arterial bulb of the bluespotted seabream, Pagrus caeruleostictus (Valenciennes, 1830), collected in Mauritanian waters. Out of the 209 individuals examined, 30.1 % were infected with this new taxon. Spore total length ranged from 15.0 to 20.5 μm with a mean of 17.9 μm. The two polar capsules were equal in size, and pyriform and caudal appendages joined until mid-length. Morphometric analysis revealed significant differences between H. mauritaniensis n. sp. and morphologically similar species from this region as well as congeners known from other sparid hosts. Phylogenetic analysis of 18 S rDNA indicated that this new species is closely related to Henneguya pagri, reported recently from Pagrus major off Japan. Bayesian inference and maximum likelihood analyses of the 18 S rDNA dataset also revealed that species of marine Henneguya reported forming pseudocysts in the hearts of their fish hosts were closely related. Histological analysis of the H. mauritaniensis n. sp. pseudocysts embedded in the arterial bulb of P. caeruleostictus suggests that these parasites may cause considerable pathology, which may impact negatively on the health of the fish host. Finally, we discussed the importance of a combination of morphological and molecular analysis for species description because of high variability in size within the same taxa.

Description of a New Species of Myxozoan from Notropis hudsonius in the Great Lakes Region of Canada

Myxobolus burti n. sp. is described from striated muscle of Notropis hudsonius (Cyprinidae) collected from localities in Lake Superior, Lake Michigan, Lake Huron, Lake St. Claire, Lake Erie, Lake Ontario, and the St. Lawrence River. Myxobolus burti is intracellular, forming thin-walled, cigar-shaped plasmodia within striated muscle cells of the body. It exhibits disporoblastic, oval spores, approximately 10 µm long, 8 µm wide, and 6 µm thick, with a length-to-width ratio of 1.3 ∶ 1. They resemble most closely those of Myxobolus bellus Kudo, 1934, and Myxobolus mutabilis Kudo, 1934, but have polar capsules unequal in length (5.3 vs. 4.7 µm) and oblique filament coils. The new parasite was not encountered in routine examination of other small-bodied fishes at collection locations and thus looks to be specific to N. hudsonius. A comparative plate of similar species encountered during surveys of these fishes in the northeast is presented to contrast the uniqueness of the new species.

A New Species of Myxozoan (Myxosporea) from the Brain and Spinal Cord of Rainbow Trout (Oncorhynchus mykiss) from Idaho

A new species of Myxosporea, Myxobolus neurotropus n. sp., is described from the brain and spinal cord of rainbow trout (Oncorhynchus mykiss) from Duncan Creek, Owyhee County, Idaho. Spores are oval, have 2 pyriform polar capsules, and possess a thick spore wall (sutural rim) with a short intracapsular offshoot. The mean spore dimensions are length 11.8 microm, width 10.8 microm, and thickness 8.8 microm. This myxozoan is compared to other described Myxobolus species found in cranial tissues of salmonids in terms of spore morphology and phylogenetic analysis. Because it is found in brain and spinal cord, it is encountered while performing screening tests for Myxobolus cerebralis, the causative agent of salmonid whirling disease. Where chronic inflammation and granulomatous lesions are associated with M. cerebralis, histological examination shows no host response to M. neurotropus n. sp. A diagnostic polymerase chain reaction (PCR) test is included as an aid in properly identifying the species.

Thelohanellus habibpuri sp. n. (Myxozoa: Bivalvulida) from the tropical freshwater fish rohu, Labeo rohita (Hamilton-Buchanan, 1882) in West Bengal, India: Light and electron microscope observations

Abstract A new species of myxozoan (Myxozoa: Bivalvulida) Thelohanellus habibpuri sp. n. parasitic in tropical freshwater fish collected from the Habibpur, West Bengal, India is described in this paper. T. habibpuri was found in the Pectoral fin of Labeo rohita (Hamilton-Buchanan, 1882). The diagnostic characters of T. habibpuri are: generally oval milky-whitish plasmodia attached in the pectoral fin of host fishes; spore egg-shaped to ovoid with slightly tapering anterior and rounded posterior end, averaging 13.9 × 8.5 μm in size; a single oval-round polar capsule 6.0 × 4.9 μm in diameter, with polar filament wound in 3-4 coils. Finely granular sporoplasm containing two slightly oval nuclei (1.4 μm in diameter) and a small iodinophilous vacuole (3.0 μm in diameter) present in the spore.SEM study of this myxozoan reveals the anterior extremity of spore is truncated. The Cnidocyst discharge channel appear as a dark area. The longitudinal wavy surface are visible on the spore.

Kudoa trifolia sp. n. – molecular phylogeny suggests a new spore morphology and unusual tissue location for a well‐known genus

A new species of myxozoan, Kudoa trifolia sp. n., was found in various organs of the golden grey mullet, Liza aurata (Risso), and the thinlip mullet, L. ramada (Risso), from the western Mediterranean. Spores developed in subspherical plasmodia of 0.28-1 mm diameter within connective tissue, predominantly in the spleen, the outer wall of the gall bladder and the gut, the mesenteries and occasionally also in the gills. The spores of K. trifolia differ from the commonly known shape of Kudoa by considerable enlargement of one of the four valve cells, thus forming a 'spore body', which contains the major part of the binucleate sporoplasm. Scanning electron microscopy of the spores revealed the presence of grape-like appendages, which occur in bundles terminally on the valve cells. Phylogenetic analysis based on the 18S rDNA sequence of K. trifolia showed that this species is deeply embedded in the genus Kudoa despite its aberrant morphology and host tissue location. This suggests important amendments to the morphological diagnosis of the genus Kudoa.