ABSTRACT
ABSTRACT Introduction: Nocardiosis is a rare bacterial infection caused by Nocardia spp. However, an increasing incidence has been described whereby data about epidemiology and prognosis are essential. Methods: A retrospective descriptive study was conducted among patients with positive Nocardia spp. culture, from January 2019 to January 2023, at a Terciary Hospital in Portugal. Results: Nocardiosis was considered in 18 cases with a median age of 63.8-years-old. At least one immunosuppressive cause was identified in 70% of patients. Five patients had Disseminated Nocardiosis (DN). The lung was the most common site of clinical disease (77.8%) and Nocardia was most commonly identified in respiratory tract samples. The most frequently isolated species were Nocardia nova/africana (n = 7) followed by Nocardia cyriacigeorgica (n = 3) and Nocardia pseudobrasiliensis (n = 3). The majority of the patients (94.4%) received antibiotic therapy, of whom as many as 55.6% were treated with monotherapy. The most frequently prescribed antibiotic was trimethoprim-sulfamethoxazole. Selected antimicrobial agents were generally effective, with linezolid and cotrimoxazole (100% Susceptibility [S]) and amikacin (94% S) having the most activity against Nocardia species. The median (IQR) duration of treatment was 24.2 (1-51.4) weeks for DN; The overall one-year case fatality was 33.3% (n = 6) and was higher in the DN (66.7%). No recurrence was observed. Conclusion: Nocardiosis is an emerging infectious disease with a poor prognosis, particularly in DN. This review offers essential epidemiological insights and underscores the importance of gaining a better understanding of the microbiology of nocardiosis. Such knowledge can lead to the optimization of antimicrobial therapy and, when necessary, guide appropriate surgical interventions to prevent unfavorable outcomes.
ABSTRACT
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.
Subject(s)
Animals , Perciformes , Myxozoa , Fish Diseases , Capillaries , Gills , HemagglutinationABSTRACT
Abstract A histopathological survey was conducted to investigate the presence of microparasites in fish Archosargus probatocephalus in a river near Maceió, Brazil. Light microscope observations of fragments of gill showed the presence of small cysts containing numerous myxospores that were morphologically identified as Henneguya. Transmission electron microscopy observations further revealed several gill cells containing groups of prokaryotic cells within large cytoplasmic vacuoles. Each infected host cell displayed a single vacuole containing a variable number of Rickettsia-like cells (up to 11), some of which presented the dumbbell shape characteristic of binary fission. The Rickettsia-like cells were pleomorphic, without a nucleus and with chromatin dispersed in the cytoplasm. They had a thin electron-dense wall of Gram-negative type. The morphology of these prokaryotic was similar to those of the order Rickettsiales and was described as a Rickettsia-like organism. Histopathological evaluation showed that several vacuole membranes had a lysed appearance. Some had ruptured, thus allowing direct contact between the Rickettsia-like organism and the cytoplasm of the host cell. The rupturing of the branchial epithelium may have contributed towards reduction of the surface area of the gills, but it is not possible to say that this was the cause of the host's death.
Resumo Um levantamento histopatológico foi realizado para pesquisar a presença de microparasitas, no peixe Archosargus probatocephalus, em um rio próximo a Maceió, Brasil. Observações ao microscópio óptico de fragmentos de brânquias mostraram a presença de pequenos cistos contendo numerosos mixósporos, identificados morfologicamente como Henneguya. Ocasionalmente, na microscopia eletrônica de transmissão, foram observados vários corpos citoplasmáticos de inclusão, grupo aparentemente de células procarióticas que vivem dentro de um grande vacúolo citoplasmático de algumas células branquiais. As células hospedeiras infectadas tinham um único vacúolo contendo um número variável de células do tipo Rickettsia, até 11, algumas das quais em forma do haltere, característica da fissão binária. Essas células eram pleomórficas sem núcleo, tendo a cromatina dispersa no citoplasma e possuíam uma parede densa de elétrons finos do tipo Gram-negativo. A morfologia dessas células procarióticas foi semelhante àquelas da ordem Rickettsiales e foram descritas como organismos tipo Rickettsiae. A histopatologia mostra várias membranas de vacúolos circundantes com aspetos lisados, enquanto outras apresentam rupturas que mostram contato direto do organismos tipo Rickettsiae com o citoplasma da célula hospedeira. A ruptura do epitélio branquial pode ter contribuído para a redução da superfície das brânquias, mas não é possível afirmar que foi a causa da morte do hospedeiro.
Subject(s)
Animals , Rickettsia Infections/microbiology , Perciformes/microbiology , Fish Diseases/microbiology , Fish Diseases/pathology , Gills/microbiology , Gills/ultrastructure , Rickettsia/ultrastructure , Rickettsia Infections/pathology , Rickettsia Infections/veterinary , BrazilABSTRACT
Abstract: The distribution of aquatic insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) can be influenced by factors such as water quality, habitat integrity and biogeography. The present study evaluated the structure of EPT assemblages in streams in the Cerrado, a global biodiversity hotspot. Samples were collected from 20 streams in two protected areas: Parque Estadual do Mirador (10 streams) and Parque Nacional da Chapada das Mesas (10 streams). A total of 1987 specimens were collected, representing 46 taxa of EPT. The two study areas did not differ significantly in taxonomic richness of EPT genera (t = -1.119, p = 0.279) and abundance of individuals (t = 0.268, p = 0.791) but did differ in genus composition (Pseudo-F = 2.088, R2 = 0.103, p = 0.015) and environmental variables (Pseudo-F = 2,282, R2 = 0.112, p = 0.014). None of the tested environmental variables were correlated with the community but a spatial filter captured an effect of the spatial distribution of streams. The region of the study is located in MATOPIBA, which is the last agricultural frontier of the Cerrado. Therefore, it is important that there is police and monitoring so that the "Parque Estadual do Mirador" and the "Parque Nacional da Chapada das Mesas" continue to play their role in conserving biodiversity in the future.
Resumo: A distribuição de insetos aquáticos das ordens Ephemeroptera, Plecoptera e Trichoptera (EPT) pode ser influenciada por fatores como qualidade da água, integridade do habitat e biogeografia. O presente estudo avaliou a estrutura das assembleias do EPT em riachos do Cerrado, um hotspot de biodiversidade global. Foram coletadas amostras em 20 riachos em duas áreas protegidas: Parque Estadual do Mirador (10 riachos) e Parque Nacional da Chapada das Mesas (10 riachos). Um total de 1987 espécimes foram coletados, representando 46 táxons de EPT. As duas áreas de estudo não diferiram significativamente na riqueza taxonômica dos gêneros EPT (t= -1,119; p= 0,279) e abundância de indivíduos (t= 0,268; p= 0,791), mas diferiram na composição do gênero (Pseudo-F= 2,088, R2= 0,103; p= 0,015) e variáveis ambientais (Pseudo-F= 2,282; R2= 0,112; p= 0,014). Nenhuma das variáveis ambientais testadas foi correlacionada com a comunidade, mas um filtro espacial capturou um efeito da distribuição espacial dos riachos. A região do estudo está localizada em MATOPIBA, que é a última fronteira agrícola do Cerrado. Portanto, é importante que exista fiscalização e monitoramento para que o "Parque Estadual do Mirador" e o "Parque Nacional da Chapada das Mesas" continuem desempenhando seu papel na conservação da biodiversidade no futuro.
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Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.
Resumo Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis (Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.
Subject(s)
Animals , Phagocytes/ultrastructure , Apicomplexa/ultrastructure , Oocysts/ultrastructure , Crassostrea/parasitology , Brazil , Apicomplexa/isolation & purification , Microscopy, Electron, TransmissionABSTRACT
A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.
Subject(s)
Animals , Female , Male , Fishes/parasitology , Gallbladder/parasitology , Myxozoa/ultrastructure , Brazil , Microscopy, Electron, Transmission , Myxozoa/classification , Myxozoa/isolation & purification , RiversABSTRACT
Objetivou-se avaliar o interesse de estudantes de graduação em Administração pela área de Finanças. Foram empregados cinco construtos (Conhecimento Técnico, Relevância Prática, Qualidade do Docente, Relevância Interdisciplinar e Interesse na Carreira), tendo-se, a priori, a proposição de que cada um deles deveria impactar positivamente no interesse dos alunos. A amostra é composta de 303 estudantes de instituições de ensino superior, públicas e privadas, de quatro Estados brasileiros. Os dados foram tratados por meio da análise fatorial exploratória, da regressão linear múltipla e da análise de clusters. Entre os principais resultados, observou-se que as proposições formuladas não foram rejeitadas, comprovando a influência positiva dos cinco construtos no interesse dos estudantes. A análise de clusters revelou três grupos: entusiastas, interessados e avessos à disciplina.
The objective of this study was to evaluate the interest of Business Administration undergraduate students in the Finance area. To achieve this objective, five constructs were used (Technical Knowledge, Practice Relevance, Teacher Quality, Interdisciplinary Relevance and Career Interest), assuming that each construct should impact positively the students´ interest. The sample consisted of 303 students, from public and private higher educational institutions, in four Brazilian States. Data were analyzed by means of factor analysis, multiple linear regression analysis and cluster analysis. The main results indicated that the propositions were not rejected, so confirming the positive influence of the five constructs on the students´ interest. Cluster analysis revealed three groups: enthusiastic, interested and averse to discipline.
Se trató de evaluar el interés de estudiantes de graduación en Administración por el área de Finanzas. Se emplearon cinco constructos (Conocimiento Técnico, Relevancia Práctica, Calidad del Docente, Relevancia Interdisciplinaria e Interés en la Carrera) teniéndose, a priori, la proposición de que cada uno de ellos debería impactar positivamente en el interés de los alumnos. La muestra se compuso con 303 estudiantes de instituciones de enseñanza superior, públicas y privadas, de cuatro Estados brasileños. Los datos se trataron por medio del análisis factorial exploratorio, de la regresión lineal múltiple y del análisis de clusters. Entre los principales resultados se observó que las proposiciones formuladas no fueron rechazadas, comprobando la influencia positiva de los cinco constructos en el interés de los estudiantes. El análisis de clusters reveló tres grupos: entusiastas, interesados y contrarios a la disciplina.
Subject(s)
Humans , Male , Female , Universities , Financial Management , Organization and Administration , Professional Competence , Professional Training , StudentsABSTRACT
Myxidium volitans sp. nov. (Myxozoa: Myxidiidae) parasitizing the hypertrophied green-brownish gallbladder of the teleost Dactylopterus volitans, collected in the Atlantic coast near Niterói, Brazil was described based on ultrastructural studies. The spores were fusiform, sometimes slightly crescent-shaped on average 21.7 ± 0.3 µm (mean ± standard deviation) (n = 50) long and 5.6 ± 0.4 µm (n = 30) wide. The spore wall was thin and smooth, comprising two equally-sized valves joined by a hardly visible sutural ridge. Spores containing two pyriform polar capsules (PC) (5.0 ± 0.4 × 2.3 ± 0.3 µm) (n = 30) are situated in each extremity of the spore. The PC wall was composed of hyaline layer (0.20-0.29 µm thick) and by a thin external granular layer. Each PC contains a polar filament (PF) with irregular arrangements that was projected from its apical region to the bases of PC and coiled laterally from bases to the tip of PC. Some regular striations and S-like structures in the periphery of the PFs with four-five irregular sections were observed. Based on the spore morphology, ultrastructural differences and the specificity of the host we describe this parasite as a new myxosporidian, named M. volitans sp. nov.
Subject(s)
Animals , Female , Male , Gallbladder , Myxozoa/ultrastructure , Perciformes , Brazil , Microscopy, Electron, Transmission , Myxozoa , MyxozoaABSTRACT
A myxosporean parasite in the gill lamellae of the freshwater teleost fish, Sciades herzbergii (Ariidae) (Block, 1794), from the Poti River (Northeast of Brazil) was described by light and electron microscopy studies. Polysporic histozoic cyst-like plasmodia containing several life-cycle stages, including mature spores, were observed. The spores were pyriform and uninucleate, measuring 9.15 ± 0.39 ìm (n = 50) long, 4.36 ± 0.23 ìm (n = 25) wide and 2.61 ± 0.31 ìm (n = 25) thick. Elongated pyriform polar capsules (PC) were of equal size (4.44 ± 0.41 ìm long and 1.41 ± 0.42 ìm in diameter) and each contained a polar filament with 9-10 coils obliquely arranged in relation to the axis of PC. The PC wall was composed of two layers of different electron densities. Histological analysis revealed the close contact of the cyst-like plasmodia with the basal portion of the epithelial gill layer, which exhibited some alterations in the capillary vessels. Based on the morphological and ultrastructural differences, the similarity of the spore features to those of the genus Myxobolus and the specificity of this host to previously described species, we describe a new species named Myxobolus sciades n. sp. in this study.
Subject(s)
Animals , Female , Male , Fish Diseases/parasitology , Fishes/parasitology , Myxobolus/ultrastructure , Parasitic Diseases, Animal/parasitology , Brazil , Gills/parasitology , Life Cycle Stages , Microscopy, Electron, Transmission , Myxobolus/classification , Myxobolus/physiology , RiversABSTRACT
A fish-infecting myxosporean, Henneguya hemiodopsis sp. n., found infecting the gills of Hemiodopsis microlepis and collected from the Poty River near the city of Teresina, Brazil, was described based on ultrastructural studies. The parasite occurred within large whitish polysporic plasmodia (up to 200 ìm in diameter) containing asynchronous developmental sporogonic stages, mainly mature spores. The spores measured 19.7 ± 0.9 ìm in total length (n = 30) and the ellipsoidal spore body was 10.8 ± 0.5 ìm long, 3.3 ± 0.4 ìm wide and 2.5 ± 0.5 ìm thick. The spores were composed of two equal shell valves adhering together along the straight suture line, with each valve having equal-sized caudal tapering tails measuring 8.7 ± 0.6 ìm in length. The spores were surrounded by a thin anastomosed network of microfibrils, more evident on the tails. There were two symmetric elongated bottle-like polar capsules 3.5 ± 0.3 ìm long and 1.0 ± 0.2 ìm wide, each with a polar filament with five to six coils. Given the morphological and ultrastructural differences from previously described parasites and the specificity of the host species, we propose a new species, named H. hemiodopsis sp. n.
Subject(s)
Animals , Female , Male , Fish Diseases/parasitology , Fishes/parasitology , Gills/parasitology , Myxozoa/ultrastructure , Parasitic Diseases, Animal/parasitology , Spores, Protozoan/ultrastructure , Brazil , Myxozoa/classification , RiversABSTRACT
O cachorro-de-orelhas-curtas Atelocynus microtis é uma das espécies mais raras de Canídeos Sul-americanos. Os relatos são muito raros e a inexistência de animais cativos também sugere distribuição limitada e densidades baixas. No período de 16 de agosto a 12 de outubro de 2006, foi realizado um monitoramento fotográfico na Floresta Nacional do Jamari, que é uma Unidade de Conservação de Uso Sustentável e possui plano de manejo com seu zoneamento ambiental definido. Os registros fotográficos de Atelocynus microtis foram obtidos nas regiões centro-oeste e noroeste da unidade, áreas formadas por Floresta Ombrófila Densa, com pontos de Floresta Ombrófila Aberta. As áreas onde foram capturadas as imagens fotográficas de Atelocynus microtis, estão em Zona de Manejo Florestal e em Zona de Mineração, por enquanto sem exploração. A partir destes fatos, a sugestão seria que o zoneamento ambiental desta Unidade de Conservação levasse em consideração este achado e fosse alterado para que a espécie fosse mais bem estudada na região antes da exploração das áreas. Como estudos relacionados a esta espécie são praticamente inexistentes, esta nota se torna importante, contribuindo com dados sobre a ecologia do A. microtis.
The Short-eared dog Atelocynus microtis is one of the most rare species of South America Canids. It is rarely reported in inventories or faunal surveys and the absence of captive animals also suggest a restrict distribution and low densities. Between August 16th 2006 and October 12th 2006, a photographic monitoring using camera traps (infrared-triggered), was carried out at the Jamari National Forest. This is a sustainable use conservation unity and has a management plan with its defined environmental zones. The Atelocynus microtis photos were captured in the Central-west and North-west areas of the Jamari National Forest, areas constituted by Dense Evergreen Forest with Open Evergreen Forest spots. The areas where the images of A. microtis were captured are in forest management zone and in mining zone, which still not exploited. Based on these facts, we suggest the management plan of this Conservation Unity took this finding into consideration and altered it, so this species could be better studied in the region, before its exploitation. As there are hardly any studies related to this species, this note becomes important, contributing to data about the A. microtis ecology.
Subject(s)
Behavior , Data Collection , Fauna , Ecosystem/classification , Ecosystem/adverse effects , Mammals/classification , Mammals/growth & developmentABSTRACT
Coccidians are pathogenic protoparasites found in various fish species. In this report, we used light and electron microscopy to study the morphological and ultrastructural features of Calyptospora serrasalmi, a coccidian parasite found to parasitize two additional species of the teleostean genus Serrasalmus, S. striolatus and S. rhombeus, from the Amazon river and the lagoonal region of Recife, Brazil, respectively. Infection involved only the liver parenchyma, with the coccidians occurring as isolated oocysts or in clusters of up to 40-50 oocysts encapsulated by a layer of connective tissue. Several life cycle stages were observed in the same section, with oocysts being the most evident. Each spherical oocyst (~25.5 um in diameter) contained four sporocysts, each surrounded by a thin membranous veil. The sporocysts were pear-shaped (11.8x6.0 um) with an attached apical sporopodium that had several small lateral projections (up to 0.5 um long). These small projections were formed by the same material as the sporocyst wall and were distributed over the basal portion of the wall in 10-12 longitudinal series. The sporocysts lacked a Stieda body and contained two vermiform sporozoites. Calyptospora serrasalmi was distinguishable from previously described species on the basis of sporocyst morphology.
Subject(s)
Animals , Coccidia/ultrastructure , Fish Diseases/parasitology , Fishes/parasitology , Microscopy, Electron, TransmissionABSTRACT
Microsporidians (Microsporidia) can parasitize commercially important marine mollusks, including bivalves. In this report, we provide a brief description of the ultrastructure of the microsporidian Steinhausia mytilovum that occurs in the oocyte cytoplasm of the mussel Mytella guyanensis (Mollusca, Bivalvia, Mytillidae) from the Amazon river estuary. Mussel ovaries were fixed, stained and examined using differential interference contrast optics (DIC). The parasite developed in an intracytoplasmic vacuole containing a variable number of spores (up to 14). Mature spores were 2.3 ± 0.3 ìm long and 1.7 ± 0.3 ìm wide (n = 25 each). Transmission electron microscopy revealed two types of intracytoplasmic vacuoles, one containing spores with a light (less dense) cytoplasm that corresponded to the maturation phases, and the other containing mature, dense, granular spores that showed specific microsporidian structures. The anchoring disc and the anterior zone of the polar filament were surrounded by the polaroplast. The polar filament was isofilar and consisted of a double (rarely triple) coil with 9-10 turns. The ultrastructural morphology of these spores suggested that they belonged to S. mytilovum.
Subject(s)
Bivalvia , Bivalvia/parasitology , Microsporidia , Microsporidia/cytology , Microsporidia/ultrastructure , Brazil , Microscopy, Electron, TransmissionABSTRACT
Rodlet cells (RCs) are fish cells considered to be regulatory elements, ion transportation cells, secretory cells, parasitic cells, transport units of genetic material, non-specific immune cells and endogenous in nature cells. In this report, we describe the ultrastructure of RCs collected from the gills and kidneys of two species of freshwater teleosts (family Curimatidae) in Brazil: Curimata macrops Eigenmann & Eigenmann, 1889 from the Poty river, near the city of Teresina in the State of Piauí, and Curimata inornata Vari, 1989 from the Amazon river near the city of Belém in the State of Pará. A variable number of RCs was observed in these tissues, with a higher frequency in gills compared to the kidneys. No other organs were investigated. RCs were observed in healthy fish and in fish parasitized by a myxosporean of the genus Henneguya. The RCs consisted of a thick-layered capsule enclosing a variable number of small, dense rodlets surrounded by several vacuoles and a nucleus. The capsule was a cytoplasmic structure composed of thick fibrillar elements surrounded externally by the plasmalemma. The capsule and surrounding plasmalemma had a smooth, undulating surface with several microvilli projecting towards the surrounding cells. Some of the microvilli located in the apical zone of the RCs were in contact with the disorganized microfibrils of the capsules. The nucleus was located laterally or basally and showed condensed chromatin at the periphery. The ultrastructural organization of the apical zone of the RCs suggested that these cells may be involved in secretory functions. This is the first report of RCs in these two species of Brazilian fish.
Subject(s)
Animals , Adult , Gills/parasitology , Gills/ultrastructure , Respiratory Physiological Phenomena , Gills , Kidney , Brazil , Homeostasis , Fishes/anatomy & histologyABSTRACT
In this report, we describe the ultrastructural morphology of rickettsialike organisms (RLOs) present in gill epithelial tissue of the oyster, Crassostrea rizophorae, from the estuarine region of the Parnaíba river, on the northeastern Atlantic coast of Brazil. Numerous rod-shaped RLOs formed microcolonies that were located in intracytoplasmic vacuoles up to 85 micrometers in diameter. These RLOs, which measured about 2 micrometers x 0.6 micrometers, had ultrastructural characteristics of prokaryotes that included a plasma membrane and a thin, Gram-negative type cell wall. Some nondividing RLOs had a transversal constriction indicative of binary fission. The disappearance of the apical cilia with concomitant lysis of the gill epithelial cells close to the parasitized cells suggested that the RLOs may be associated with mortality in these oysters. Numerous free RLOs were seen following disruption of the vacuoles during host cell necrosis and degeneration. This is the first description of a Rickettsiales-like organism in the Atlantic fauna of Brazil.
Subject(s)
Animals , Ostreidae/parasitology , Rickettsia/pathogenicity , Rickettsia/ultrastructure , BrazilABSTRACT
Lutzomyia umbratilis has been incriminated as the principal vector of Leishmania (Viannia) guyanensis in the Amazon region, north of the Amazon river. The discovery of this sandfly naturally infected with L. (V.) braziliensis in the north of the State of Mato Grosso, where L. (V.) braziliensis has been isolated from humans, however, has reinforced an hypothesis that L. umbratilis could represent a complex of sibling species based on the apparent infrequency of human infection with L. (V.) guyanensis in Amazonian Brazil south of the Amazon river system. In order to ascertain wether or not L. umbratilis is in fact a complex of sibling species, studies were made on the morphology, morphometry and ecology of populations of this sandfly in Brazil (states of Amazonas, Amapá, Pará and Mato Grosso) and Venezuela (state of Bolívar). Analyzes of morphology (qualitative characters) for the populations from both countries failed to provide evidence of a complex of species, but 75% of the morphometric (quantitative) characters did reveal statistically significant differences separating the Brazilian and Velezuelan populations. The phenetic analysis did not provide evidence of heterogeneity among the Brazilian populations. In the state of Mato Grosso L. umbratilis was abundant in the forest canopy but could not be found on the trunks of the same trees. This contrasts greatly with past observations on the behaviour of this sandfly in the north of the Amazon River system, where there is a heavy concentration of the vector on the lower parts of the large trees, particularly in the early morning. Studies on the eco-epidemiology of cutaneos leishmaniasis in the State of Acre, Brazil, strongly suggest the participation of L. umbratilis in the transmission of L. (V.) guyanensis in the south of the Amazon river.
Lutzomya umbratilis es el principal transmisor de Leishmania (Viannia) guyanensis en la Amazonia, al norte del río Amazonas. El hallazgo de este flebótomo infectado naturalmente por L. (V.) braziliensis al norte del estado de Mato Grosso, donde el mismo parásito circula entre los humanos, refuerza la hipótesis de que L. umbratilis podría representar un complejo de especies, ya que este flebótomo nunca fue informado en asociación a L. (V.) guyanensis al sur del río Amazonas. Para conocer mejor este vector de la leishmaniosis tegumentaria americana (LTA) en Brasil y Venezuela, y verificar si de hecho representa un complejo de especies, se llevaron adelante estudios morfológicos, morfométricos y ecológicos. Los análisis de caracteres cualitativos (morfología) en poblaciones de Brasil (estados de Amazonia, Amapá, Pará y Mato Grosso) y de Venezuela (estado de Bolívar) no presentaron pruebas de un complejo de especies en las poblaciones investigadas. Mientras tanto, 75% de los caracteres morfométricos (cuantitativos), revelaron diferencias estadísticamente significativas que separan las poblaciones brasileñas y venezolanas. El análisis fenético no logró probar heterogeneidad entre las poblaciones brasileñas. EN el estado de Mato Grosso, aun habiendo encontrado ejemplares de L. umbratilis en la copa de los árboles y aunque esta especie es muy antropofílica, no se pudo encontrar ejemplares sobre el tronco de los árboles de gran porte, un típico comportamiento de la especie en Amazonia. Estudios sobre la epidemiología de la LTA en el estado de Acre sugieren fuertemente la participación de L. umbratilis en la cadena epidemiológica de L. (V.) guayanensis, al sur del río Amazonas.
Subject(s)
Ecoepidemiology , Psychodidae , Brazil , Leishmania guyanensis , Amazonian EcosystemABSTRACT
Oocystsof Nematopsis mytella, an apicomplexa gregarine parasite of the mussel Mytella falcata (fam. Mytelidae) and of the oyster Crassostrea rizophorae (fam. Ostreidae). Were collected from Itamaracá Island and Suape, two distinct zones in the estuarine region of the northeastern coast of Brazil, near the city of Recife. The oocysts were examined by light and transmission electron microscopy. No morphological and ultrastructural differences were observed between oocysts the two host species. The oocysts were engulfed by the cytoplasm of host phagocytes, with each phagocyte containing 1-19 oocysts (usually 3-5). Each oocyst was located in the center of a spherical to ellipsoidal parasitophorous vacuole (PV) 20-25 um in diameter. The oocyst (13.2 um long and 8.4 um wide) consisted of an external wall 0.6 um thich surrounded by an internal, uninucleated sporozoit. The apical region of the wall of each oocyst contained a circular micropyle 0.8 um in diameter covered by an operculum. The oocyst wall was connected to the PV membrane by a complex network of anastomosed microfibrils. The PV matrix contained 1-2 dense bodies and the periphery was occupied by numerous glycogen particles. This is the first record of a Nematopsis sp. from the northeastern coast of Brazil and only the second from Brazil as a country.
Subject(s)
Animals , Bivalvia , Cellular Structures , Bivalvia/parasitology , Ostreidae , ParasitesABSTRACT
In this study we report some ultrastructural details of some recently described species of parasites of the phylum Myxozoa (Henneguya adherens, H. malabarica, H. striolata, H. testicularis, Tetrauronema desaequalis and Myxobolus braziliensis), found in fishes of the Amazon region. Some ultrastructural aspects of the life cycle with special reference to the spore morphology are described. The action of the parasites in host fishes is analyzed and the harmful effects of their parasitic activity are discussed.
Neste trabalho descrevemos alguns detalhes ultraestruturais de novas espécies de protoparasitas do phylum Myxozoa (Henneguya adherens, . malabarica, . striolata, . testicularis, Tetrauronema desaequalis and Myxobolus braziliensis), recentemente encontrados e descritos em peixes da bacia amazônica. São descritos os aspectos ultraestruturais do ciclo de vida dos parasitas, incluindo o esporo, vetor biológico responsável pela transmissão do parasita. Por outro lado, é analizada a ação do parasita no hospedeiro e referidos efeitos nefastos da ação parasitária.
ABSTRACT
Morphological and ultrastructural aspects of the spermatozoon of Curimata inornata Vari, 1989 (Pisces, Teleostei) is described by light and transmission electron microscopy, the spermatozoon head contains a nucleus ovoid-shaped, with granular chomatin electron dense, a short middle piece and a tail, with the classic 9+2 axoneme.
Estão descritos aspectos morfológicos e ultraestruturais do espermatozóide de Curimata inornata Vavi, 1989 (Pisces,Teleostei) observados com microsopia óptica e microscopia eletrônica de transmissão. O espermatozóide é constituído de cabeça, contendo um núcleo ovoide com cromatina granular densa, uma peça intermediária curta e uma cauda com a constituição axonêmica clássica de microtúbulos de 9p+2.