Larval trematodes hosted by Biomphalaria straminea in the Brazilian semiarid region: implications for schistosomiasis control.

The present study aimed to identify larval trematodes shed by snails found in water bodies used by urban communities in a former schistosomiasis endemic area in the state of Piauí, in the Brazilian semiarid region. A malacological survey was performed followed by analysis of the cercariae shed by the snails after light exposure. Biomphalaria straminea specimens (n=1,224) were obtained from all seven collection sites. Cercariae shed by snails were i) single tailed, in which one type of cercariae was identified ( Echinostoma cercariae), and ii) with bifurcated tail (brevifurcate apharyngeate distome, brevifurcate pharyngeate distome, and longifurcate pharyngeate distome [strigeocercaria]). Brevifurcate apharyngeate distome were further examined and the presence of spikes in swimming membranes enabled the identification of Spirorchiidae cercariae in all individuals, demonstrating the absence of cercariae compatible with Schistosoma mansoni . Nevertheless, the accurate diagnosis of S. mansoni circulation in former endemic areas is still necessary.

Larval trematodes hosted by Biomphalaria straminea in the Brazilian semiarid region: implications for schistosomiasis control

@#The present study aimed to identify larval trematodes shed by snails found in water bodies used by urban communities in a former schistosomiasis endemic area in the state of Piauí, in the Brazilian semiarid region. A malacological survey was performed followed by analysis of the cercariae shed by the snails after light exposure. Biomphalaria straminea specimens (n=1,224) were obtained from all seven collection sites. Cercariae shed by snails were i) single tailed, in which one type of cercariae was identified (Echinostoma cercariae), and ii) with bifurcated tail (brevifurcate apharyngeate distome, brevifurcate pharyngeate distome, and longifurcate pharyngeate distome [strigeocercaria]). Brevifurcate apharyngeate distome were further examined and the presence of spikes in swimming membranes enabled the identification of Spirorchiidae cercariae in all individuals, demonstrating the absence of cercariae compatible with Schistosoma mansoni. Nevertheless, the accurate diagnosis of S. mansoni circulation in former endemic areas is still necessary.

The influence of health education on the prevalence of intestinal parasites in a low-income community of Campos dos Goytacazes, Rio de Janeiro State, Brazil.

In a recent study by our group on the prevalence of intestinal parasitic infections and on the knowledge, attitudes and practices of local residents of Campos dos Goytacazes, Rio de Janeiro, Brazil, we observed that about 50% of the inhabitants were parasitized and had some knowledge of intestinal parasitic infections but did not apply this knowledge in daily practice. We were thus motivated to implement strategies in health education to promote preventive measures in the locality. The goal of the present work was to evaluate the influence of health education on the prevalence of intestinal parasitic infections in the region in an effort to strengthen public policies for controlling these diseases in Brazil. The methodology adopted was based on action-research and a theoretical framework of health promotion. Our results demonstrate that the study population exhibited an enhanced awareness of the importance of disease from intestinal parasitic infections. Attitudes and practices related to prevention were significantly improved after the shared health education. In conclusion, this study allowed the shared construction of knowledge that reflected the true needs of the residents.

Nematodes of Rhynchophorus palmarum, L. (Coleoptera: Curculionidae), vector of the Red Ring Disease in coconut plantations from the north of the Rio de Janeiro State.

Rhynchophorus palmarum, the palm weevil, has been reported as a pest of palms and sugarcane plants. The Red Ring Disease is an infectious plant disease caused by nematodes. The etiological agent, Bursaphelencus (Rhadinaphelencus) cocophilus (Nematoda: Aphelenchoididae), completes its life cycle within 9 to 10 days inside the palm tree. The main symptom is a permanent wilting of the plant aerial parts. Previous studies stated that B. cocophilus cohabits with other nematodes the gut of R. palmarum. The aim of this study is to identify nematodes collected from palm weevil found in coconut plantations from the north of the Rio de Janeiro State. Light (LM) and scanning electron microscopy (SEM) analyses were carried on samples of infected R. palmarum and fragments and fresh juice of infected plants with B. cocophilus. Observations of R. palmarum fecal material made by LM and SEM showed three species cohabiting these samples, being also present in fresh juice and fragments of infected coconut tree: B. cocophilus, Teratorhabditis palmarum (Nematoda: Rhabditidae) and Diplogasteritus sp (Nematoda: Diplogasteridae). These findings confirm previous studies, which related that R. palmarum own a varied nematode fauna. Nematodes associated to B. cocophilus probably could be co-participates of the etiology of the Red Ring disease.

Fine structure and cytochemical analysis of the intestinal wall along the body of adult female of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

Litomosoides chagasfilhoi is a filariid nematode parasite of the abdominal cavity of the wild rodent Akodon cursor (Winge, 1887), that has been described and used in Brazil as a new model for human filariasis. The fine structure of the intestine of this nematode was analyzed based on observations made by light and transmission electron microscopies of serial sections along the body. Cytochemical analysis was carried out to investigate the composition of the intestinal wall. This structure consisted of a basal lamina and an epithelium of variable thickness, composed of cells that have an irregular shape. The cytoplasm of intestinal cells contains few organelles: vacuoles, lysosomal bodies, spheroid bodies, endoplasmic reticulum, and many large lipid droplets. In the anterior portion of the intestine, the lysosomal bodies, spheroid bodies, and vacuoles presented positive reaction for acid phosphatase, and carbohydrates were detected in lysosomal bodies. The midbody and posterior regions presented less organelles and lipid droplets, and nuclei were more abundant. Residues of L-fucose were detected by Ulex europaeus lectin binding in the midbody sections. Basic proteins were associated to lipid droplets, in the posterior region. In the whole extension of the intestine, carbohydrates were detected on tight junctions. These results indicate that the metabolized material in the epithelium can contribute to the microfilariae development and also probably can be involved with the excretory/secretory mechanism of these nematodes.

Further studies on the structural analysis of the cuticle of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

In order to obtain further information on the structural organization of the cuticle of nematodes, this structure was isolated from adult forms of the filariid Litomosoides chagasfilhoi. The purity of the fraction was determined by light and transmission electron microscopy, deep-etching, high resolution scanning electron microscopy, atomic force microscopy, immunocytochemistry, gel electrophoresis (SDS-PAGE) and Western blot. The epicuticle presented a rugous surface with parallel rows and several globular particles that could be involved in the absorption of nutrients and secretion of products. Analysis by SDS-PAGE of purified cuticles revealed five major polypeptides corresponding to 151, 41, 28, 13 and 11 kDa. A polyclonal antibody against a synthetic 18 amino-acid peptide that corresponds to the sequence of domain E of the Haemonchus contortus3A3 collagen gene recognized several protein bands on the Western blot of purified cuticle, and labeled all cuticular layers, as shown by immunocytochemistry.

Deep-etched view of the cuticle of adults of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

The fine structure of the cuticle of the filariid nematode Litomosoides chagasfilhoi is described, based on observations made by transmission electron microscopy and deep-etched replicas. The cuticle consists of a trilaminate epicuticle, the outermost layer that interfaces with the host and four other layers: cortical, intermediate, fibrous and basal. In deep-etched replicas, the cortical layer is formed by a meshwork of globular particles and fibers with a thickness of 4-8 nm. The intermediate layer is electron-lucid and contains a densely-stained line. In deep-etched replicas, it is composed by a meshwork of fibers with longitudinal orientation. The fibrous layer is the thickest and most electron-dense and consists of two types of fibers: thick (9-26 nm) and thin (3-6 nm). The innermost basal layer is intimately associated with the hypodermis. In common with other nematodes, the cuticle of L. chagasfilhoi presents channels that are probably involved in nutrient acquisition and transport.

Fine structure, freeze-fracture and deep-etch views of the sheath and cuticle of microfilariae of Litomosoides chagasfilhoi (Nematoda: Filarioidea).

The fine structure of the sheath and the cuticle of microfilariae of the filariid Litomosoides chagasfilhoi is described based on observations made using transmission electron microscopy (TEM) and especially on deep-etched replicas of fully developed intrauterine microfilariae and mature stretched microfilariae released by adult females through cultivation in vitro. TEM showed that the sheath was trilaminated. In contrast, in deep-etching replicas the sheath presented two layers: an inner layer composed of tightly arranged globular material, and an outer layer whose external surface was relatively smooth. Both in thin sections and in classical freeze-fracture and deep-etched replicas, the cuticle presented two distinct regions: an external one, corresponding to the trilaminated epicuticle, and an inner one, corresponding to the inner cuticle. Deep-etching replicas revealed that the epicuticle presented several structures on the annulations of the microfilariae and that the inner region was composed by two parallel rows of globular structures.

Amphimerus bragai n. sp. (Digenea: Opisthorchiidae), a parasite of the rodent Nectomys squamipes (Cricetidae) from Minas Gerais, Brazil.

Amphimerus bragai n.sp. (Digenea, Opisthorchiidae) from the bile ducts of a rodent from the State of Minas Gerais, Brazil, Nectomys squamipes (Cricetidae), is described. The new species as studied by both light and scanning electron microscopy. A table is presented comparing the measurements of the new species with those of A. lancea (Diesing, 1850) and A. vallecaucensis Thatcher; 1970, parasites of dolphins and marsupials, respectively. The new species is similar in size and body form to A. vallecaucensis from which it differs in having a vitellarium that extends to the acetabulum while that of the former species are limited to the posterior one-third of the body. Additionally, the new species is from a rodent.

Prevalence of two species of Litomosoides (Nematoda: Filarioidea) parasites of Akodon cursor (Rodentia: Muridae) from southeastern Brazil

Two species of filariids, Litomosoides silvai and Litomosoides chagasfilhoi, were collected from the thoracic and abdominal cavities, respectively, of Akodon cursor, from Catimbau Grande, Rio Bonito, Rio de Janeiro, Brazil. Fifty-eight rodents were necropsied and 15 (25.9) were parasitized. Four of the 15 infected rodents (26.7) presented concurrent infections, but each species had separate and specific sites of infection. This is the first report of a rodent species parasitized with naturally occurring, concurrent infections with two species of filarial worms.

Litomosoides chagasfilhoi sp. nov. (Nematoda:Filarioidea) parasitizing the abdominal cavity of Akodon cursor (Winge, 1887) (Rodentia:Muridae) from Brazil.

Litomosoides chagasfilhoi sp. nov., a parasite of the abdominal cavity of the wild rodent Akodon cursor (Winge. 1887), is described herein according to investigations conducted by light and scanning electron microscopy. The leading morphological characteristics of the new species are as follows: the buccal capsule is higher than it is wide and has walls thinner than the lumen, and the left spicule presents a handle longer than the blade, whose edges from large membranous wings folded longitudinally. This new species is different from L. silvai Padilha and Faria, 1977, living in the thoracic cavity of the same host.

Prevalence of two species of Litomosoides (Nematoda: Filarioidea) parasites of Akodon cursor (Rodentia: Muridae) from southeastern Brazil.

Two species of filariids, Litomosoides silvai and Litomosoides chagasfilhoi, were collected from the thoracic and abdominal cavities, respectively, of Akodon cursor, from Catimbau Grande, Rio Bonito, Rio de Janeiro, Brazil. Fifty-eight rodents were necropsied and 15 (25.9%) were parasitized. Four of the 15 infected rodents (26.7%) presented concurrent infections, but each species had separate and specific sites of infection. This is the first report of a rodent species parasitized with naturally occurring, concurrent infections with two species of filarial worms.

Emended description of Litomosoides silvai (Nematoda:Filarioidea) of Akodon cursor (Rodentia:Muridae).

The emendation of the description of Litomosoides silvai Padilha and Faria, 1977 was based on results obtained by light and scanning electron microscopy. The filarioids were obtained from Akodon cursor (syn. Akodon arviculoides) found at the Catimbau Grande site in Rio Bonito, Brazil. Some features that are added to the original description include the en face view of the cephalic end, the width of the buccal capsule, the nerve ring, and the pattern of cuticular striations for both sexes. Also included are the morphologic characteristics of the spicules, the number of papillae, the area rugosa, the lateral line of the male, the shape of the buccal capsule, vulva, and anus of the female, and the microfilariae. The morphology of the spicules confirms that this species is part of the carinii line, according to Bain et al. (1989).