[Genetic selection of Biomphalaria glabrata and Biomphalaria tenagophila seeking the alteration of the susceptibility and resistance to Schistosoma mansoni]. / Seleção genética de Biomphalaria glabrata e Biomphalaria tenagophila visando a alteração da suscetibilidade e resistência ao Schistosoma mansoni.

Generations of Biomphalaria glabrata and Biomphalaria tenagophila selected genetically for resistance and susceptibility to Schistosoma mansoni of strains BH and SJ were used in a study of the trematode adaptation to the intermediate host. Descendants of the planorbids were obtained by self-fertilization of the mollusks that became susceptible or resistant after exposure to the miracidia of Schistosoma mansoni. For Biomphalaria glabrata they were obtained from the following generations: Parental, F1S (Susceptible), F1R (Resistant), F2S and F2R. For Biomphalaria tenagophila the studied generations were: Parental, F1S, F1R and F50S. The comparison of the infection rates presented by the different generations showed that the increase in susceptibility was more easily obtained in both species. The difficulty in increasing the resistance of the mollusks to Schistosoma mansoni has important epidemiologic implications.

Behavior in Mus musculus of Schistosoma mansoni from mollusks treated with hydrocortisone.

Twenty mice were exposed to cercariae from mollusks treated with hydrocortisone and another 20 mice received cercariae from non-treated mollusks. The behavior of the parasites from the two groups of mollusks was compared based on the ability of cercariae to penetrate mice, on the total number of worms recovered after eight weeks of infection, on the relationship between the number of penetrating cercariae and the number of recovered worms and on the number of eggs in the feces. Treating the mollusks with hydrocortisone did not alter the ability of cercariae to penetrate mice nor did it affect the total number of worms recovered. The number of female worms, the number of coupled worms and the number of eggs in the feces were greater in mice infected by cercariae from mollusks treated with hydrocortisone.

[Influence of hydrocortisone on Schistosoma mansoni development in Biomphalaria glabrata]. / Influência da hidrocortisona no desenvolvimento do Schistosoma mansoni em Biomphalaria glabrata.

The effect of hydrocortisone on the development of BH strain of S. mansoni in B. glabrata snails is evaluated. Snails in a randomly chosen group were submitted to hydrocortisone during four days. In the second day of hydrocortisone exposure, the snails were exposed, each, to ten S. mansoni miracidia. Another group, not treated with hydrocortisone, was exposed to miracidia and observed in the same manner. Various items of data were observed: the infection rate, survival time, prepatent period and total number of cercariae released. It was found that the snails in the group treated with hydrocortisone had a higher infection rate, shorter prepatent periods, produced more cercariae and also had longer survival times. This suggests that the hydrocortisone in snails induces a decrease in resistance to schistosome infection and facilitates the development of the trematode, while also reducing adverse infection effects, thereby leading to longer snail survival.

[The efficiency of the examination of compressed fecal samples for Schistosoma mansoni eggs]. / Eficiência do diagnóstico coproscópico de Schistosoma mansoni em fezes prensadas.

The control of schistosomiasis depends mostly upon the sensitivity of stool examinations. We used both the Kato-Katz technique and the compression of samples between the slide and a polypropylene cover glass, according to Ferreira. Out of 1,282 samples collected between 1998 and 2000 in the Palha District, Municipality of Bananal, São Paulo State, Brazil, 105 (8.2 %) were positive. The first and second methods revealed 90 (7%) and 88 (6.9 %) positive cases, respectively. According to the kappa statistic, both methods were in agreement. In Bananal, the proportion of positive cases and egg per gram (epg) values are low, which calls for the examination of larger than usual volumes of feces. The viability of Schistosoma mansoni eggs can also be checked when using the second method, which dispenses with glycerin solution, measuring plates and sieves. The latter cause a further loss of precision in epg determinations.

[Schistosoma mansoni: a study of pathogenesis of Santa Rosa strain (Campinas, SP, Brasil) in mice]. / Schistosoma mansoni: estudo da patogenia da linhagem Santa Rosa (Campinas, SP, Brasil) em camundongos.

The present paper reports the comparison between a newly isolated strain of S. mansoni in the city of Campinas (SP, Brazil) named SR, with the strains BH (Belo Horizonte, MG, Brazil) and SJ (São José dos Campos, SP, Brazil). The study was done using mice experimentally infected with 70 cercariae from sympatric snails: B. glabrata for the BH strain and B. tenagophila for the SJ and SR strains. The data obtained revealed that the new strain is less pathogenic than the other two, since it yielded fewer worms and shed eggs, a lower number of granulomas and a smaller granuloma size in the liver and intestine.

Applications of RNA Interference in Schistosomiasis: Gene Function Identification and Development of New Therapies.

The study of Schistosoma species has undergone a dramatic change in recent years mainly due to transcriptome, proteome, and genome analyses. In order to better understand the biology of the parasite and to develop new and more efficient/specific drugs, scientists have now the task to translate genetic information into functional data. The present paper aims to review the use of RNA interference (RNAi), a versatile technique used in gene silencing, for the dissection of the cellular/molecular biology of Schistosoma spp. In addition, we will review information on the recent development of a new generation of RNA-based drugs. Examples of specific experimental approaches will be presented and discussed, such as identification of gene function, development of therapies by targeting eggs, miracidia (as a strategy for environmental use), sporocysts (for infestation control in the intermediate host), and schistosomula/adult worms (as a treatment strategy). Furthermore, some of the main advantages, drawbacks, and future directions of these new applications and techniques will also be discussed.

Liposomal-praziquantel: efficacy against Schistosoma mansoni in a preclinical assay.

Currently, schistosomiasis mansoni is treated clinically with praziquantel (PZQ). Nevertheless, cases of tolerance and resistance to this drug have been reported, creating the need to develop new drugs or to improve existing drugs. Considering the small number of new drugs against Schistosoma mansoni, the design of nanotechnology-based drug delivery systems is an important strategy in combating this disease. The aim of this study was to evaluate the activity of PZQ containing liposome (lip.PZQ) on S. mansoni, BH strain. Mice were treated orally with different concentrations of PZQ and lip.PZQ 30 and 45 days following infection. The number of worms, recovered by perfusion of the hepatic portal system, and the number of eggs found in the intestine and liver were analysed. Parasite egg counts were also performed. The most active formulation for all parameters was 300mg/kg of lip.PZQ, since as it decreased the total number of worms by 68.8%, the number of eggs in the intestine by 79%, and the number of hepatic granulomas by 98.4% compared to untreated controls. In addition, this concentration decreased egg counts by 55.5%. The improved efficacy of the treatment with lip.PZQ, especially when administered 45 days following infection, compared with the positive-control group (untreated) and the groups that received free PZQ, can be explained by greater bioavailability in the host organism; the preferred target of lip.PZQ is the liver, and lip.PZQ is better absorbed by the tegument of S. mansoni, which has an affinity for phospholipids.

Susceptibility of Argentinean Biomphalaria tenagophila and Biomphalaria straminea to infection by Schistosoma mansoni and the possibility of geographic expansion of mansoni schistosomiasis.

INTRODUCTION: Human migration and the presence of natural vectors (mollusks) of Schistosoma mansoni are the primary causes of the expansion of mansoni schistosomiasis into southern areas of South America. Water conditions are favorable for the expansion of this disease because of the extensive hydrographic network, which includes the basins of the Paraná and Uruguay rivers and favors mollusk reproduction. These rivers also aid agriculture and tourism in the area. Despite these favorable conditions, natural infection by S. mansoni has not yet been reported in Argentina, Uruguay, or Paraguay. METHODS: Two species of planorbid from Argentina, Biomphalaria straminea and B. tenagophila, were exposed to the miracidia of five Brazilian strains of S. mansoni. RESULTS: Biomphalaria tenagophila (Atalaya, Buenos Aires province) was infected with the SJS strain (infection rate 3.3%), confirming the experimental susceptibility of this Argentinian species. Biomphalaria straminea (Rio Santa Lucía, Corrientes province) was susceptible to two Brazilian strains: SJS (infection rate 6.7%) and Sergipe (infection rate 6.7%). CONCLUSIONS: These results demonstrate that species from Argentina have the potential to be natural hosts of S. mansoni and that the appearance of foci of mansoni schistosomiasis in Argentina is possible.

A Study of the Granulomatous Responses Induced by Different Strains of Schistosoma mansoni.

The increased pathogenesis of the Schistosoma mansoni BH strain compared with the SJ strain has been attributed to the number of granulomas formed in experimental infections, which increase the mortality in definitive hosts. The aim of the present study was to investigate the development of granulomas around the eggs of the S. mansoni BH and SJ strains and to determine whether this host reaction was strain specific. Four experimental groups were analyzed. Two groups contained mice inoculated in the caudal vein with eggs from the S. mansoni BH or SJ strains and the other two contained mice that were infected with cercariae of the BH strain prior to being inoculated with eggs. The number of granulomas per tissue area in the lungs and liver, as well as the size of the granulomas, was analyzed to characterize the response to schistosome infection. The largest granulomatous responses were observed around eggs of the BH strain. Granulomas covered a larger area in the lungs of mice that were previously infected with cercariae and subsequently inoculated with eggs of the BH strain. These results indicated that specific granulomatous responses occurred following an infection with the BH and SJ strains of S. mansoni.

Experimental Evaluation of the Pathogenicity of Different Strains of Schistosoma mansoni.

The pathogenesis of three different Schistosoma mansoni strains from the Brazilian states of Minas Gerais (BH strain) and São Paulo (SJ and SD strains) was evaluated in experimentally infected mice. Observations of the most severe clinical cases among local patients treated (SD strain) in the city of Campinas (São Paulo, Brazil) formed the basis of this study. Mice were used as definitive hosts and were infected with cercariae from Biomphalaria tenagophila (SJ and SD strains) and Biomphalaria glabrata (BH strains). The parameters analyzed were as follows: number of S. mansoni eggs in mice feces; number of granulomas per tissue area in liver, spleen, lungs, pancreas, and ascending colon; measurements of hepatic and intestinal granulomas; number of adult worms; and measurements of trematode eggs. The comparison among the three strains indicated that the SD strain, isolated in Campinas, presented a higher worm recovery relative to the number of penetrating cercariae. In addition, when compared to the SJ and BH strains, the SD strain demonstrated similar pathogenicity to the BH strain, with a greater quantity of granulomas in the viscera, as well as larger granulomas and eggs. Furthermore, a greater quantity of trematode eggs was also shed in the feces.

Acute schistosomiasis in brazilian traveler: the importance of tourism in the epidemiology of neglected parasitic diseases.

Parasitic infectious diseases acquired in tourist areas may pose a challenge to physicians and to travel medicine practitioners. Acute schistosomiasis may be seen in returning travelers and migrants after primary infection. This form of schistosomiasis is frequently misdiagnosed due to its temporal delay and its nonspecific presentation and might occur even in countries where the disease is endemic, such as in Brazil. The patient developed the acute phase of schistosomiasis with severe clinical manifestations. The quantitative analysis revealed the presence of 240 eggs per gram of stool. The treatment was administered with oxamniquine, and the control of cure of the patient was monitored and was favorable. The present paper aims to emphasize the importance of a detailed clinical history including information regarding travel history.

Effect of piper tuberculatum extract on adult schistosoma mansoni: in vitro and in vivo tests

Schistosomiasis is a severely neglected disease with a wide geographical distribution. It affectsapproximately 210 million people in the world and at least 800 million people live in risk areas.The search for new drugs to treat this parasitosis is significant due to the appearance of strains of theworm that are resistant to the currently available drugs. The retrieval of compounds extracted fromplants that act on these parasites has increased scientific investigation of this subject. The presentstudy demonstrates, in vitro and in vivo, the action of crude extract of Piper tuberculatum on adultSchistosoma mansoni. The extract was shown to be quite effective in the in vitro tests, causing softtissue alterations and acting on the reproductive system of females and the mortality of the worms,with a greater effect on males. The in vivo experiment was performed with infected Mus musculusand a decrease in the number of eggs in the first and second oogram stages was found, suggestingaction on oviposition...

A esquistossomose, doença negligenciada grave e de larga distribuição geográfica, atinge cerca de210 milhões de pessoas no mundo e ao menos 800 milhões vivem em área de risco. A busca de novosmedicamentos para o tratamento desta parasitose é relevante em razão do aparecimento de linhagensdo verme resistentes aos fármacos disponíveis. A obtenção de compostos extraídos de plantas comação sobre parasitos tem incrementado a investigação científica sobre este assunto. O presentetrabalho mostra a ação in vitro e in vivo do extrato bruto de Piper tuberculatum sobre adultosde Schistosoma mansoni. O extrato mostrou-se bastante eficaz nos ensaios in vitro, provocandoalterações tegumentares, tendo ação no sistema reprodutor das fêmeas e na mortalidade dos vermes com maior ação sobre os machos. Como resultado em experimentos in vivo, realizados em Musmusculus infectados, observou-se a diminuição do número de ovos de 1º e 2º estágios em oogramas,o que sugere uma ação na postura de ovos...

Improvement of the oral praziquantel anthelmintic effect by cyclodextrin complexation.

Schistosomiasis is a parasitic disease which kills a half million people per year, all over the world. Praziquantel (PZQ) is the drug-of-choice for schistosomiasis because of its effectiveness, ease of administration, and low cost. However, poor solubility restricts its delivery, especially via the oral route. In this study, we describe beta-cyclodextrin (beta-CD) complexation as an alternative to improve the PZQ bioavailability. Physicochemical analysis were performed to characterize the inclusion complex formed between PZQ and beta-CD. Differential scanning calorimetry (DSC) thermograms and morphological analysis using scanning electronic microscopy (SEM) gave evidences of the complex formation. Diffusion NMR experiments allowed determination of the fraction of PZQ bound to beta-CD (37%) and the association constant (941 +/- 47 M(-1)). The in vivo evaluation of the complexation on the effect of PZQ was performed on mice infected with Schistosoma mansoni (BH strain); after 15 days of treatment with the PZQ:beta-CD complex the efficacy, evaluated by the number of remaining alive worms, was 99%, against 59% elicited by plain PZQ.

Susceptibility of Argentinean Biomphalaria tenagophila and Biomphalaria straminea to infection by Schistosoma mansoni and the possibility of geographic expansion of mansoni schistosomiasis

Introduction Human migration and the presence of natural vectors (mollusks) of Schistosoma mansoni are the primary causes of the expansion of mansoni schistosomiasis into southern areas of South America. Water conditions are favorable for the expansion of this disease because of the extensive hydrographic network, which includes the basins of the Paraná and Uruguay rivers and favors mollusk reproduction. These rivers also aid agriculture and tourism in the area. Despite these favorable conditions, natural infection by S. mansoni has not yet been reported in Argentina, Uruguay, or Paraguay. Methods Two species of planorbid from Argentina, Biomphalaria straminea and B. tenagophila, were exposed to the miracidia of five Brazilian strains of S. mansoni. Results Biomphalaria tenagophila (Atalaya, Buenos Aires province) was infected with the SJS strain (infection rate 3.3%), confirming the experimental susceptibility of this Argentinian species. Biomphalaria straminea (Rio Santa Lucía, Corrientes province) was susceptible to two Brazilian strains: SJS (infection rate 6.7%) and Sergipe (infection rate 6.7%). Conclusions These results demonstrate that species from Argentina have the potential to be natural hosts of S. mansoni and that the appearance of foci of mansoni schistosomiasis in Argentina is possible. .

The influence of hydrocortisone on cellular defence mechanisms of Biomphalaria glabrata.

Since the internal defense system of mollusks consists of cellular and humoral mechanisms, we examined the role of hydrocortisone in mollusks defense cells and the influence of this steroid on the development of Schistosoma mansoni in its intermediary host. Hydrocortisone had an immunosuppressive action in Biomphalaria glabrata, as reflected in the reduced number of defense cells and the altered cell physiology. Histopathological analysis showed that hydrocortisone facilitated the intramolluscan development of S. mansoni, by reducing the extent of the inflammatory response, seen as a greater number of viable sporocysts with no surrounding hemocytes.

Saponins from Swartzia langsdorffii: biological activities.

The presence of saponins and the molluscicidal activity of the roots, leaves, seeds and fruits of Swartzia langsdorffii Raddi (Leguminosae) against Biomphalaria glabrata adults and eggs were investigated. The roots, seeds and fruits were macerated in 95% ethanol. These extracts exerted a significant molluscicidal activity against B. glabrata, up to a dilution of 100 mg/l. Four mixtures (A2, B2, C and D) of triterpenoid oleanane type saponins were chromatographically isolated from the seed and fruit extracts. Two known saponins (1 and 2) were identified as beta-D-glucopyranosyl-[alpha-L-rhamnopyranosyl-(1->3)- beta-D-glucuronopyranosyl-(1->3)]-3beta-hydroxyolean-12-ene-28 -oate, and beta-D-glucopyranosyl-(1->3)-beta-D-glucuronopyranosyl-(1 ->3)]-3beta-hydroxyolean-12-ene-28-oate, respectively. These two saponins were present in all the mixtures, together with other triterpenoid oleane type saponins, which were shown to be less polar, by reversed-phase HPLC. The saponin identifications were based on spectral evidence, including H- H two-dimensional correlation spectroscopy, nuclear Overhauser and exchange spectroscopy, heteronuclear multiple quantum coherence, and heteronuclear multiple-bond connectivity experiments. The toxicity of S. langsdorffii saponins to non-target organisms was prescreened by the brine shrimp lethality test.

Seleção genética de Biomphalaria glabrata e Biomphalaria tenagophila visando a alteração da suscetibilidade e resistência ao Schistosoma mansoni / Genetic selection of Biomphalaria glabrata and Biomphalaria tenagophila seeking the alteration of the susceptibility and resistance to the Schistosoma mansoni

Gerações de Biomphalaria glabrata e Biomphalaria tenagophila selecionadas geneticamente para resistência e suscetibilidade ao Schistosoma mansoni das linhagens BH e SJ foram utilizadas no estudo da adaptação do trematódeo ao hospedeiro intermediário. As gerações dos planorbídeos foram obtidas por autofecundação dos moluscos que se apresentaram suscetíveis ou resistentes após a exposição aos miracídios de Schistosoma mansoni. Para Biomphalaria glabrata foram obtidas as gerações: Parental, F1S (Suscetível), F1R (Resistente), F2S e F2R. Para a Biomphalaria tenagophila foram estudadas as gerações: Parental, F1S, F1R e F50S. A comparação das taxas de infecção apresentadas pelas diferentes gerações mostrou que, em ambas as espécies, o aumento da suscetibilidade foi mais facilmente obtido do que o aumento da resistência. A dificuldade em aumentar a resistência do molusco ao S. mansoni tem fortes implicações epidemiológicas.

Behavior in Mus musculus of Schistosoma mansoni from mollusks treated with hydrocortisone

Vinte camundongos foram expostos a cercárias oriundas de moluscos tratados com hidrocortisona e outros vinte receberam cercárias de moluscos não tratados. O comportamento dos parasitas dos dois grupos foi comparado com base na habilidade das cercárias em penetrar nos camundongos, no número total de vermes recuperados, após oito semanas de infecção, na relação entre o número de cercárias penetrantes e o número de vermes recuperados e o número de ovos nas fezes. O tratamento dos moluscos com hidrocortisona não alterou a habilidade das cercárias em penetrar nos camundongos nem afetou o número total de vermes recuperados. O número de vermes fêmeas, o número de vermes acasalados e o número de ovos nas fezes aumentaram em camundongos infectados por cercárias de moluscos tratados com hidrocortisona.

Relaçäo entre a patogenicidade do Schistosoma mansoni em camundongos e a susceptibilidade do molusco vetor. II. Número de ovos nas fezes e número e tamanho dos granulomas nas vísceras / Relationship between the pathogenicity of Schistoma mansoni in mice and the susceptibility of the vector mollusc. II. Number of eggs in the feces and number and size of granulomas in the visceras

Estuda a influência da susceptibilidade de moluscos vetores do S. mansoni no desenvolvimento da patogenicidade do trematódeo no hospedeiro definitivo. Foram utilizadas progênies de moluscos Biomphalaria tenagophila e Biomphalaria glabrata selecionadas para o caráter susceptibilidade ao S. mansoni das linhagens SJ e BH, respectivamente. Cercárias oriundas das geraçöes P, F1, F2, F3 e F4 foram usadas para a infecçäo de camundongos Swiss, que foram sacrificados oito semanas após a exposiçäo às larvas. Por esta ocasiäo, verifica o número de ovos nas fezes e o número de granulomas no fígado, baço e intestino. Avalia, também, o tamanho das reaçöes granulomatosas nestas vísceras. Conclui que a maior susceptibilidade de B. tenagophila induziu a uma maior eliminaçäo de ovos do parasita nas fezes. Verifica maior número de granulomas por área de tecido hepático em roedores infectados com cercárias oriundas de moluscos mais susceptíveis. Nos mesmos roedores, constata relaçäo inversa entre a área dos granulomas esplênicos, hepáticos e instestinais e a taxa de infecçäo dos moluscos que forneceram as cercárias para a infecçäo dos camundongos

Aspectos imunológicos e parasitológicos em Biomphalaria tenagophila infectadas por Schistosoma mansoni e outros Digenea / Immunological and parasitological aspects of Biomphalaria tenagophila infected by Schistosoma mansoni and other Digenea

Estuda o comportamento de amebócitos de Biomphalaria tenagophila infectadas por Schistosoma mansoni, por outros Digenea e a resistência à superinfecçäo, presente em infecçöes mistas. Foi verificada a atividade fagocitária dos amebócitos, o número destas células circulantes, a reaçäo amebocitária nos tecidos, o perfil eletroforético da hemolinfa, além da reaçäo de imunodifusäo. Conclui que moluscos infectados por outros Digenea apresentam resistência à superinfecçäo por S. mansoni, sendo que os amebócitos parecem näo ter participaçäo direta na destruiçäo dos esporocistos de S. mansoni nesta eventualidade. Nos moluscos infectados, observa maior número de amebócitos circulantes e aumento de capacidade fagocitária destas células