Casos autoctones de esquistossomose mansonica em criancas de Recife, PE / Casos autoctonos de esquistosomiasis mansonica en ninos de Recife, PE, Brasil / Autochthonous cases of schistosomiasis in children in Recife, Northeastern Brazil

OBJETIVO : Investigar criadouros com moluscos hospedeiros e casos humanos autóctones para esquistossomose. MÉTODOS : Entre julho de 2010 e setembro de 2012 foram realizados: (1) levantamento malacológico para busca ativa de criadouros, coleta e identificação de caramujos Biomphalaria positivos para Schistosoma mansoni em Recife, PE; (2) inquérito de prevalência com 2.718 escolares, de sete a 14 anos, para diagnóstico de casos de esquistossomose; (3) exame clínico e ultrassonografia nos casos positivos para S. mansoni. Os casos foram investigados quanto à sua autoctonia e avaliados clinicamente. Os casos e criadouros foram georreferenciados e espacializados. RESULTADOS : Foram identificados 30 criadouros de B. straminea , quatro deles potenciais focos de transmissão, uma vez que os testes moleculares identificaram DNA de S. mansoni nos caramujos coletados. Foram diagnosticadas 14 crianças com esquistossomose; entre elas, cinco foram consideradas casos autóctones da doença. CONCLUSÕES : Ações emergenciais pela vigilância em saúde são necessárias para evitar que a esquistossomose se endemize em Recife, como acontece em localidades litorâneas do estado de Pernambuco. .

OBJETIVO Investigar criaderos con moluscos hospedadores y casos humanos autóctonos para esquistosomiasis. MÉTODOS Se ejecutaron: estudio malacológico para búsqueda activa de criaderos, colecta e identificación de caracoles Biomphalaria positivos para S. mansoni en Recife, PE, entre julio de 2010 y septiembre de 2012, pesquisa de prevalencia con 2.718 escolares, de siete a 14 años, para diagnóstico de casos de esquistosomiasis, examen clínico y de ultrason en los casos positivos para S. mansoni. Los casos fueron investigados con respecto a su autoctonía y evaluados clínicamente. Los casos y criaderos fueron geo-referenciados y espacializados. RESULTADOS Se identificaron 30 criaderos de B. straminea, cuatro de ellos potenciales focos de transmisión, luego que las pruebas moleculares identificaron DNA de S. mansoni en los caracoles colectados. Se diagnosticaron 14 niños con esquistosomiasis, entre ellas cinco fueron considerados casos autóctonos de la enfermedad. CONCLUSIONES Acciones de emergencia para vigilancia de salud son necesarias para evitar que la esquistosomiasis se vuelva endémica en Recife como sucede en localidades del litoral de Pernambuco. .

OBJECTIVE : Investigate breeding sites with host snails and autochthonous human cases of schistosomiasis. METHODS : Between July 2010 and September 2012 were performed: (1) malacological survey searching for breeding sites, collection and identification of Biomphalaria snails positive for Schistosoma mansoni in Recife, PE, Northeastern Brazil; (2) prevalence survey in 2,718 schoolchildren aged from seven to 14 years old to identify cases of schistosomiasis, clinical examination and ultrasound in positive cases of S. mansoni. The autochthony of the cases was investigated and the case were clinically evaluated. The cases and breeding sites were georeferenced and spatially described. RESULTS : The results identified 30 breeding with B. straminea, four of which were potential foci of transmission, as molecular testing identified snails with S. mansoni DNA. There were 14 children diagnosed with schistosomiasis, of which five were considered to be autochthonous cases of the disease. CONCLUSIONS : Urgent measures are required in order to avoid schistosomiasis becoming endemic to Recife, as has happened in other coastal areas of the state of Pernambuco. .

Activity of praziquantel on in vitro transformed Schistosoma mansoni sporocysts

Praziquantel (PZQ) is effective against all the evolutive phases of Schistosoma mansoni. Infected Biomphalaria glabrata snails have their cercarial shedding interrupted when exposed to PZQ. Using primary in vitro transformed sporocysts, labeled with the probe Hoechst 33258 (indicator of membrane integrity), and lectin of Glycine max (specific for carbohydrate of N-acetylgalactosamine membrane), we evaluated the presence of lysosomes at this evolutive phase of S. mansoni, as well as the influence of PZQ on these acidic organelles and on the tegument of the sporocyst. Although the sporocyst remained alive, it was observed that there was a marked contraction of its musculature, and there occurred a change in the parasite's structure. Also, the acidic vesicles found in the sporocysts showed a larger delimited area after contact of the parasites with PZQ. Damages to the tegument was also observed, as show a well-marked labeling either with Hoechst 33258 or with lectin of Glycine max after contact of sporocysts with the drug. These results could partially explain the interruption/reduction mechanism of cercarial shedding in snails exposed to PZQ.

Sex determination and female reproductive development in the genus Schistosoma: a review

Os parasitas do genero Schistosoma situam-se entre os primeiros metazoarios que desenvolvem sexos separados, determinado cromossomicamente no ovo fertilizado. Apesar da ocorrencia de cromossomos sexuais especificos, as femeas de Schistosoma nao atingem a maturidade somatica e sexual sem a presenca dos machos. Na verdade, um dos aspectos mais controversos e, ao mesmo tempo, mais fascinantes, envolvendo o desenvolvimento sexual das femeas esta em se desvendar a natureza do estimulo que controla e mantem tal processo. Muito embora a natureza do estimulo (fisico ou quimico) seja motivo de controversia, concordam os mais diferentes autores que o acasalamento e um requisito indispensavel para que ocorra a maturacao e migracao das femeas para o sitio definitivo de permanencia no sistema vascular do hospedeiro vertebrado...

Lung-migration patterns of Schistosoma mekongi and S. spindale in mouse.

Two groups of laboratory-bred Swiss albino mice were used to study the lung-migration patterns of Schistosoma mekongi and S. spindale. The first group was individually infected with 100 S. mekongi cercariae by hair-looping application on shaved abdomen. The latter group was individually exposed to 500 S. spindale cercariae by tail immersion. Each group of these infected mice was then divided into subgroups. The number of schistosomulae was determined using a lung recovery assay starting from the second day after infection and continuing for 15 consecutive days. The results revealed a sharp peak of both S. mekongi and S. spindale on the fifth day post cercarial infection.

Areas de investigación en esquistosomiasis / Research areas in schistosomiasis

La esquistosomiasis es considerada mundialmente como un problema de salud pública. En Venezuela, a partir de 1943 es iniciado un programa de control de la esquistosomiasis mansoni, lográndose una reducción acentuada de la morbi-mortalidad. Existen evidencias recientes que dicha patología ha sido subvalorada como problema de salud pública, por lo cual es necesario tomar las medidas de control más adecuadas para no permitir la pérdida de conquistas logradas en el control de la enfermedad, hace varias décadas. Por lo antes expuesto y tomando en cuenta las cuatro grandes áreas de investigación en esquistosomiasis consideradas por el TDR, han sido identificados y revisados los principales elementos de investigación básica y aplicada para el logro de objetivos. Es ofrecida información que permite detectar prioridades de investigación posibles, factibles y necesarias en nuestro país

Biology of Robertsiella kaporensis snails and Malaysian Schistosoma.

Studies on the bionomics and host-parasite relationship of Robertsiella kaporensis and Malaysian Schistosoma were investigated. The study was divided into 4 parts: cultivation of snails, R. kaporensis, and maintenance of Malaysian Schistosoma life cycle, daily cercarial shedding cycle in R. kaporensis, miracidial load and cercarial shedding pattern and the infectivity of Malaysian Schistosoma cercariae. R. kaporensis were cultured in the laboratory with the use of plastic container provided with fine sand. The snails were fed with diatoms and Saraca leaves. The development period for the snail eggs was about 20-30 days, the young grew to maturity in 14-15 weeks, and the average growth rate of snails was 0.23 mm per week. The daily cercarial shedding cycle of snails had shown that the peak emergence of cercariae of Malaysian Schistosoma occurred at night, between 6-10 pm. The miracidial load which yielded the best results in terms of percentage infection rates of snails and cercarial output was the miracidial concentration of 8 miracidia per snail. The study on infectivity of Malaysian Schistosoma cercariae has shown that there was a decrease in infectivity of the cercariae to mammalian hosts as the cercariae increased in age. The percentage infection rate of mice and numbers of worms recovered were highest in mice infected with cercariae of 0-1/2 hr. old. Infection of cercariae fell rapidly after the cercariae were 16 hr. old.

Comparative methods of infecting mice with Schistosoma mekongi.

Experiments were carried out to investigate the most suitable cercarial concentration and method of exposure for the experimental mice infected with cercariae of Schistosoma mekongi. Swiss albino mice of 2 months old were exposed individually by three methods exposure : abdominal skin exposure, tail immersion and subcutaneous injection. Cercarial concentrations of 10 to 20 cercariae per mouse were used for each method of exposure. In general, it was observed that both the infection rate and total worm recovery rose with an increase in cercarial concentration. The highest percentage infection rate and total worm recovery was found in mice infected with 20 cercariae per mouse by the abdominal skin exposure method.

Estimation of annual incidence of schistosomiasis japonica among school children in the Philippines;.

An attempt was made to estimate the annual incidence of schistosomiasis from the prevalences at ages 7 to 10 in the Philippines.