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Federal Rural University of Amaz?nia. Paragominas, PA, Brazil. Federal Rural University of Amazonia. Carlos Azevedo Research Laboratory. Bel?m, PA, Brazil. Amap? State University. Laboratory of Morphophysiology and Animal Health. Macap?, AP, Brazil. Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Laborat?rio de Epidemiologia e Imunologia Aplicada ? Leishmaniose. Ananindeua, PA, Brasil. Federal University of Par?. Laboratory of Biomolecular Technology. Bel?m, PA, Brazil. Federal Rural University of Amazonia. Carlos Azevedo Research Laboratory. Bel?m, PA, Brazil. The class Myxozoa is a group of spore-producing eukaryote organisms that parasitize both freshwater and marine fish. The multivalvulide myxosporidian parasites of the genus Kudoa infect primarily the musculature of the fish host, some species are producing enzymes (proteases) capable of digesting muscle fibers. In the present study, 50 specimens of the freshwater catfish Hypophthalmus marginatus were collected from the Tocantins River in Par?, Brazil, and were analyzed. Overall, 68% of these specimens presented infections by Kudoa parasite in the esophageal musculature. The morphology of these parasite was examined under light microscopy and nucleotide sequences of the SSU rDNA gene were obtained for phylogenetic analyses. The species formed numerous whitish pseudocysts containing square spores with rounded extremities in the apical view, and four polar capsules of equal size. In the phylogenetic analyses, Kudoa amazonica n. sp. was characterized as a sister taxon of another freshwater species, Kudoa orbicularis. The combination of morphological, morphometric, and molecular data obtained in the present study provided a conclusive diagnosis of Kudoa amazonica n. sp., which is clearly distinct from all other Kudoa taxa described to date.

Kudoa ocellatus n. sp. was found in the musculature of Astronotus ocelattus (Agassiz, 1831) from the Arari River on Marajo Island in Para, Brazil. The new species forms pseudocysts in the epaxial and hypaxial musculature composed of various spores that are pseudoquadrate in the apical view. In the lateral view, the spores were triangular or pyramidal. In the lateral view, the spores were 46 ± 0.11 μm (4.5–4.8) in length and 6.6 ± 0.3 μm (6.2–7.2) in width, with four pyriform polar capsules of equal size that measured 2.0 ± 0.16 μm (1.8–2.2) in length and 1.5 ± 0.18 μm (1.3–1.8) in width. Based on the partial (1418 bps) sequence of the SSU rDNA gene, Kudoa ocellatus n. sp. was distinct from all the other Kudoa species deposited in GenBank. The phylogenetic Bayesian Inference and P distance placed the new species together with the other Kudoa species that parasitize freshwater Amazonian fish. The morphological evidence, together with the SSU rDNA gene sequence, supported the description of Kudoa ocellatus n. sp., a distinct new species of the genus, which parasitizes a freshwater Amazonian cichlid.

The present study describes a new coelozoic, eukaryotic microparasite of the genus Ellipsomyxa Køie, 2003 (Ceratomyxidae: Myxozoa) found parasitizing the gallbladder of Satanoperca jurupari Heckel, 1840 collected in the Curiaú River Environmental Protection Area in Macapá, Amapá state, Brazil. The fish were collected using mesh cast net. The gallbladders were examined, preserved in 80% alcohol for molecular analysis (SSU rDNA gene), and fixed in Davidson for histological slide preparation. The new parasite had a prevalence of 81% in the gallbladder, asymmetric plasmodia, irregular free spores in the bladder fluid, with no cyst formation. The spores are elliptical, with characteristics of the genus Ellipsomyxa, and they had a mean length of 10.11 (8.56-10.5) μm, mean width of 7.81 (5.96-9.56) μm, and thick walls. The polar capsules are sub-spherical in shape, slightly asymmetrical, with a mean length of 3.12 (2.31-3.99) μm and mean width of 2.5 (2.22-2.95) μm, containing polar filament with five or six coils perpendicular to the longitudinal axis of the capsule. The Bayesian Inference assigned the new species to a subclade formed by a lineage of Ellipsomyxa species from the Amazon region. Ellipsomyxa tucujuensis n. sp. is the sixth species of this genus described in fish from the Amazon region, and the first for the state of Amapá.

The tambaqui (Colossoma macropomum) is a native fish species that is farmed most frequently and in the largest quantities throughout Brazil. The high production of this species from fish farms has contributed to the occurrence of emerging parasites, which may compromise fish health and productivity. In a batch of 2500 tambaqui fry acquired for experimental farming procedures in Brazil, a mortality rate of 80% was observed, with the fish swimming erratically and gasping for air at the water surface. From among the specimens that were still alive, 60 individuals were selected at random. Organs or fragments of organs containing lesions and/or cysts were examined under an optical microscope to investigate for the presence of parasitic spores. Of the 60 specimens of tambaqui analyzed, 83.3% were found to be infected in different organs, such as the gills, liver, and gallbladder with myxosporidian species belonging to four genera, namely, Myxobolus, Ellipsomyxa, Henneguya and Thelohanellus. The parasite with the greatest prevalence was Myxobolus sp., located in the gills (70%), followed by Henneguya sp. in the gills region (68.3%), Myxobolus sp. in the liver (63.3%), Thelohanellus sp. in the liver (58.3%), and Ellipsomyxa in the gallbladder (50%). This is the first report of parasitic infection caused by the genera Ellipsomyxa and Thelohanellus in C. macropomum. The present study reported the second incidence of the occurrence of the genus Thelohanellus in South America. This study suggested that the mortality among C. macropomum specimens was caused by the outbreak of myxosporidians. Keywords: Amazon, Tambaqui, Parasite, Myxozoa, Myxosporidians

Made available in DSpace on 2021-06-25T10:33:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 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 ± 2.2 μm in total length, 8.2 ± 1.0 μm in body length, 7.9 ± 0.2 μm in body width, 20.7 ± 2.4 μm in tail length and 4.8 ± 1.0 μm in thickness. The polar capsules measured 3.3 ± 0.4 in length and 1.7 ± 0.3 μm 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. Programa de Pós-graduação em Análise de Sistemas Ambientais Centro Universitário CESMAC Instituto de Biociências Departamento de Parasitologia UNESP - Universidade Estadual Paulista Câmpus de Botucatu, Distrito de Ribeirão Junior, Botucatu Carlos Azevedo Research Laboratory Federal Rural University of Amazonia (UFRA) Belém Instituto de Biociências Departamento de Parasitologia UNESP - Universidade Estadual Paulista Câmpus de Botucatu, Distrito de Ribeirão Junior, Botucatu

Henneguya jocu n. sp. (Myxosporea, Myxobolidae) is described from the gill lamellae of the marine teleost fish Lutjanus jocu, with a focus on ultrastructural and molecular features. This myxosporean forms subspherical cysts up to ∼260 μm × 130 μm long, and develops asynchronously. Mature myxospores ellipsoidal with a bifurcated caudal process. Myxospore length 10.9 ± 0.4 μm (n = 50); width, 8.2 ± 0.3 μm (n = 50); and thickness, 2.9 ± 0.5 μm (n = 50). Two equal caudal processes, 34.1 ± 1.0 μm long (n = 50); and total myxospore length, 45.2 ± 1.0 μm (n = 50). Two symmetric valves surround two ellipsoidal polar capsules, 5.0 ± 0.3 × 1.4 ± 0.2 μm (n = 20), each containing an isofilar polar filament forming 4–5 coils along the inner wall of these structures, as well as a binucleated sporoplasm presenting a spherical vacuole and several globular sporoplasmosomes. Both the morphological data and molecular analysis of the SSU rDNA gene identify this parasite as a new species of the genus Henneguya. Maximum Likelihood and Maximum Parsimony analyses further indicate that the parasite clusters within others marine Myxobolidae species, forming a group alongside other Henneguya species described from marine hosts.

A myxosporidian was found in the urinary bladder of the teleost Menticirrhus americanus Linnaeus, 1758 (Sciaenidae) collected from the South Atlantic coast of Brazil. Polysporic amoeboid plasmodia containing sporoblasts, developing pansporoblasts and spores were free in the bladder lumen. The prevalence of infection was 17.64% (15/85). Unfixed spores were spherical to subspherical, on average 10.5microm long, 9.8microm wide and 10.1microm thick (n=25), and fixed spores measured 10.1 x 9.5 x 9.7microm. The two spore valves were of equal size and each possessed prominent sutural lines and about 41 (37-45) surface ridges aligned parallel with the suture line. These ridges gave transverse sections a cog-wheel-like outline. The spores contained four pyriform polar capsules of equal size (3.20 x 2.0microm) (n=25) (fixed), each with a polar filament having 3-4 (rarely 5) coils. The binucleate sporoplasm was irregular in shape, with granular matrix and randomly distributed dense bodies. The shape and dimensions of the spore, as well as the number, position and arrangement of the surface ridges, polar capsules and polar filament indicate that this is a new species, herein designated Chloromyxum menticirrhi. The gill, liver, gall bladder and intestine of the host showed no abnormalities.

Vavraia lutzomyiae (Microsporida; Pleistophoridae) is a new species parasitic in the tropical phlebotomine sandfly, Lutzomyia longipalpis (Diptera, Psychodidae, Phlebotominae), a major vector of Leishmania chagasi in Latin America where human visceral leishmaniasis is endemic. Infected larvae and pupae were parasitized in the abdomen, and some adults were parasitized in Malpighian tubules and midgut. The sporogonial plasmodium divided by multiple divisions into up to 64 uninucleate sporoblasts. These stages were surrounded outside the plasmalemma by a thick, amorphous dense coat and transformed into a merontogenetic sporophorous vesicle within which the sporonts developed into sporoblasts. The mature microsporidian spores were broadly ellipsoidal and measured 6.1+/-0.43 x 3.1+/-0.15 microm. The spore wall consisted of a transparent endospore (approximately 100 nm) and a thin electron dense exospore (approximately 30 nm) with the outer limit slightly undulated. Spores contained a polar filament arranged peripherally in a single layer of eight to nine wide anterior coils (approximately 125 nm diameter), and three to four narrow posterior coils (approximately 70 nm diameter). Transverse sections revealed a concentric layer organization with the internal layer surrounded by numerous (up to 25) longitudinal microfibrils. The angle of tilt of the polar filament was about 65-68 degrees.

Triangulamyxa amazonica n. gen. and n. sp. (Myxozoa, Ortholineidae), found in the lumen of the intestine of the freshwater fish Sphoeroides testudineus, is described. The fish were collected from the Amazon River near the city of Algodoal, State of the Para, Brazil. Numerous irregular plasmodia containing different stages of sporogony, including spores, were observed. The plasmodia were lying free in the lumen or had slender pseudopodia-like cytoplasmic processes in contact with intestinal epithelial cells with microvilli projections. Spores, which are equilaterally triangular in valvar view with rounded pointed ends and ellipsoidal in transverse section, are ∼8.5 μm long, ∼7.6 μm wide, and ∼3.8 μm thick. The anterior end of the spores contains two equal drop-shaped polar capsules measuring 2.6 μm in length, each having an isofilar polar filament with 5–6 turns. The characteristics of the spore shape, the spore wall structure and its ridge organization, the plasmodial characteristics and the identity of the host suggest that the parasite is a new genus and species, which is herein designated T. amazonica .

The myxosporean, Agarella gracilis, a parasite in Lepidosiren paradoxa collected in the estuarine region of the River Amazon, is described using light and transmission electron microscopy. The most evident life cycle stages were the spores, found in both the testis and ovary, which appeared scantily dispersed in the lumina. The prevalence of infection was 10/30 (33.3%). In mean dimensions the mature spore was 59.7 μm in total length, composed of an elongated body 17.7 μm long, 6.6 μm wide and 5.9 μm thick, with two long slightly divergent tail-like projections of the valves. There were four pyriform polar capsules, two longer (7.0×2.4 μm) and two shorter (3.8×2.4 μm), located anteriorly in the spore body; the polar filaments of all capsules had 6–7 turns. There was a posterior binucleate sporoplasm. The morphology agrees with the original description by light microscopy, and the taxonomy of the genus is discussed. The presence of the same genus of myxosporean parasites in both dipnoan and anuran species perhaps reflects their close phylogenetic relationship.

The Amazon estuary is a unique environment, in which a wide variety of both marine and freshwater fish species can be found, providing an important source of income for local populations. Forty G. broussonnetii specimens were collected from an area adjacent to the city of Salvaterra on Marajo Island, in the Brazilian state of Para, in 2011. The necroscopic analysis of the hosts revealed the presence of milky rounded cysts throughout the palate. Microscopic analysis of the parasitized fragments revealed that the squamous epithelium covering the palate was intact, although Myxobolus sp. cysts were observed in the cytoplasm of the striated skeletal muscles of the palate, as found in other myxosporids. Overall, the macro- and microscopic findings of the present study confirm the presence of necrotizing myositis in the palate of G. broussonnetii associated with parasitism by Myxobolus sp.

A new species of a microsporidian, Loma myrophis n. sp., was found in the sub-epithelial gut tissue of the Amazonian teleost fish, Myrophis platyrhynchus (fam. Ophichthidae), forming small whitish xenomas. Each xenoma consisted externally of a thick wall formed by one layer of fibrous material surrounded by aggregate and concentric fibroblasts. Inside, there was a hypertrophic host cell with a hypertrophic branched nucleus surrounded by a hypertrophic cytoplasm containing intermingled life cycle stages, mainly mature spores. Among these cells several extruded polar filaments were observed. Sporonts were surrounded by numerous blisters with dense contents, which appeared to discharge their contents into the parasitophorous vacuole around the parasite. All spores were ellipsoidal and uninucleate, and measured about 3.45 × 1.71 m (n = 50). The polar filament was isofilar and consisted of a single coil with 13–14 turns, surrounding the posterior vacuole that occupied about half of the total volume of the spore. The xenoma, formation of the parasitophorous vacuole and the morphology of the spores were basically like those of the genus Loma . In this paper, we describe light and electron microscopical data of the xenoma, life cycle and the spores of a new microsporidian species, Loma myrophis.

Summary Numerous uninucleated phagocytes with several parasitophorous vacuoles (PV) each containing a single oocyst of an apicomplexan gregarine parasite of the mussel Mytella guyanensis (Mytelidae) from the Amazon estuary were described. The phagocytes were in close contact with the gill tissue. Each phagocyte was surrounded by a thin layer composed of electron-lucent material. The plasmalemma of the phagocyte presented numerous microvilli irregularly projected to the surrounding thin layer. The phagocyte cytoplasm was occupied by large light areas, numerous small vesicles and among them a variable number of PV each containing a single oocyst. The oocysts were 11.5 μm long and 8.2 μm wide and the wall was 0.7 μm thick. The apical zone of the wall contained a circular micropyle covered by an operculum attached to the PV membrane by a dense cord. Externally, the oocyst wall was surrounded by numerous, long and anastomosed microfibrils attached to the wall and connected to the PV membrane. Several dense bodies within the PV were observed. Each oocyst contained a single vermiform uninucleated sporozoite. This gregarine was named Nematopsis mytella n. sp. and the morphological characteristics of its oocysts were described. This parasite became the first record of Nematopsis sp. and the first gregarine from the Amazonian mussel.

Summary A new coccidian species, Calyptospora spinosa (fam. Calytosporidae) is described from liver, testis and ovary tissue of a freshwater fish, Crenicichla lepidota , from the lower Amazon river near Belem, Brazil, where it causes great mortality. Each oocyst contains four ellipsoidal sporocysts, each one surrounded by a membranous veil. Each sporocyst, containing two sporozoites, has an apical sporopodium possessing several lateral sporopodium projections. These sporocysts differ from those of the four other species of the genus Calyptospora in size and shape, in the insertion of the lateral sporopodium projections and in the identity of the host. This paper describes the morphology and ultrastructural characteristics of the oocyst and sporocyst of this coccidium and draws morphological comparisons with the other four species of the same genus.

The authors present light and electron microscopical data on a myxosporidian found in the gills of Crenicichla lepidota Heckel, 1840 (Teleostei, Cichlidae) from the Amazon river. Based on the spore morphology, it is concluded that this species belongs to the family Myxobolidae, genus Henneguya, and that it constitutes a new species: Henneguya amazonica n.sp. The fine structure of sporogenesis shows that the development follows, in general, the pattern of this and other genera. Nevertheless, some ultrastructural features are reported for the first time in the genus Henneguya: intercellular bridges between daughter generative cells as well as tubuli arranged in aggregates and dispersed within the capsular matrix. The structure of the trophozoite wall suggests that the species is not highly pathogenic, but, to ascertain the true pathogenicity of the species, further studies are needed.