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Traditionally, every two years, the International Symposium on Schistosomiasis, organized by Fundação Oswaldo Cruz, takes place in Brazil. The Symposium brings together scientists from all over the world working on different aspects of schistosomiasis. As this disease affects approximately 240 million people worldwide (1), it is crucial to appraise recent advances in schistosome biology, parasite interactions with hosts, and review progress in the development and evaluation of new tools for disease diagnosis, treatment, and control.\ud The 16th edition of the Symposium (http://www.vppcb.fiocruz.br/16symposium-schisto/_en) was scheduled to take place in August 2020 but was postponed to November 2022, due to the COVID-19 pandemic. The published papers in this Research Topic sustain our global engagement and aim to keep the research momentum on schistosomiasis, a neglected tropical disease, thriving.\ud Our infographic highlights our international engagement across 23 countries with a total of 177 authors (Figure 1). Of note, whilst intestinal schistosomiasis (Schistosoma mansoni) occurs in South America and still poses a significant public health challenge in parts of Brazil, it also occurs in Africa, alongside urogenital schistosomiasis (Schistosoma haematobium). In Asia, however, intestinal schistosomiasis is caused by a different schistosome species (Schistosoma japonicum), and the appreciation of this is essential to ensure that global research and control efforts are appropriate and complementary.

The bioassay of the molluscicidal Activities ofJ. curcasleaves againstBiomphalaria pfeifferiwas investigatedin vitro,using Crude and 70% methanolic extracts in a two-phased rapid and final screening test. The rapid screening of the crude extracts, for the minimal molluscicidal concentration (LC100), of the snails was less active (>500ppm), compared to the methanolic extracts (50and LC100values of 6 and 30ppm respectively. Further investigation based on exposure, revealed a mortality within 12 hours, which meets WHO standard of less than 24 hours for a potential molluscicide. These results confirmed thatJ.curcasleaves can be regarded as a potential molluscicide for the control of schistosomiasis and therefore encourage the cultivation of this plant in endemic regions.

Foi feita uma revisão dos levantamentos malacológicos realizados pela Fundação Nacional de Saúde em 52 municípios de 8 microrregiões do estado de Santa Catarina, Brasil, de 1981 a 1994. Cinqüenta deles foram positivos para Biomphalaria tenagophila, o único vetor do Schistosoma mansoni identificado nos 94.535 exemplares examinados. Das 1.358 localidades trabalhadas, 617 (45,4%) foram positivas, variando de 4,3% a 89,4%, por município. Os caramujos foram coletados em 0,2% a 26,3% das coleções hídricas pesquisadas, por município, sendo que 7,1% (2.013/28.120) serviam de criadourospara oplanorbídeo. Nos municípios de Araquari, Massaranduba, Joinville, Jaraguã do Sul e São Francisco do Sul, na microrregião de Joinville, foram encontrados caramujos infectados com S. mansoni. Os dois últimos são os focos de esquistossomose mansoni mais meridionais do Brasil. Outras pesquisas identificaram a B. peregrina, B. oligoza, B. schrammi, B. straminea e B. occidentalis.TA revision of the malacological surveys canied out in Santa Catarina, Brazil, by the National Health Foundation in 52 counties of 8 microregions between 1981 and 1994 was made. Fifty of them were positive for Biomphalaria tenagophila, the only schistosome vector identified in the 94,535 specimens collected. Of 1,358 districts, 617 (45.4%) were positive to the vector, varying from 4.3% to 89-4% per municipality. The percentages of water bodies with planorbids varied from 0.2% to 26.3 % and, of the total 28,120 examined, 2,013 (7.1%) were positive. Snails infected with cercariae of Schistosoma mansoni were found in the counties of Araquari, Massaranduba, Joinville, Jaraguá do Sul and São Francisco do Sul, the last two constituting the southernmost focus of schistosomiasis mansoni in Brazil. Otherplanorbid species identified were B. peregrina, B. oligoza, B. schrammi, B. straminea and B. occidentalis.

This paper describes the ecology of two species of Biomphalaria: B.glabrata and B. straminea. These species have been intensively studied in Brazil and in other countries since the 1950s. The literature in this area can be broadly subdivided into three categories, linked to three distinct historical periods: 1) an accumulated store of early studies carried out in the laboratory and in the field; 2) the development of quantitative ecological models; and 3) the development of an alternative methodology for breeding snails under seminatural conditions.Aspectos ecológicos de duas espécies brasileiras de Biomphalaria, transmissoras da esquistossomose mansônica, são discutidos no presente artigo. B. glabrata e aB. straminea têm sido intensamente estudadas no Brasil e em outros países desde a década de 50. Este artigo enfatiza três momentos que marcaram o desenvolvimento histórico de nosso conhecimento sobre a biologia destes caramujos: 1. o acervo antigo acumulado de estudos de laboratório e de campo; 2. o desenvolvimento de modelos ecológicos quantitativos; 3. o desenvolvimento de metodologia alternativa para o cultivo dos caramujos em condições seminaturais.

Studies on eight localities on the Island of Santa Catarina revealed the presence of three species of the molluscan family Planorbidae: Biomphalaria tenagophila, Drepanotrema cimex and Biomphalaria oligoza, the first one being naturally infected by Cercaria ocellifera, a furcocercaria with morphological characteristics of Cercaria caratinguensis, and by an unknown furcocercaria. Drepanotrema cimex was infected by a furcocercaria with characteristics of C. caratinguensis and by C. macrogranulosa. No natural infection was found in B. oligoza. B. tenagophila showed no susceptibility to the experimental infection by the BH-MG strain of Schistosoma mansoni from Belo Horizonte and maintained at laboratory in B. glabrata snails.Pesquisas em oito localidades da Ilha de Santa Catarina revelaram a presença de três espécies da família Planorbidae: Biomphalaria tenagophila, Drepanotrema cimex e B. oligoza, estando a primeira naturalmente infectada por Cercaria ocellifera, furcocercária com características morfológicas de C. caratinguensis e uma furcocercária desconhecida. O segundo molusco citado, estava infectado com C. macrogranulosa e com furcocercária com características de C. caratinguensis, não sendo constatada infecção natural em B. oligoza. No processo de infecção experimental com cepa BH-MG de Schistosoma mansoni, cepa originária de Belo Horizonte e mantida em laboratório em mo lusco B. glabrata, B. tenagophila não se mostrou suscetível.

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscicidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscicidal effect. The molluscicidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12ºC (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasisTestes de laboratório com soluções aquosas do látex da Euphorbia splendens var. hislopii demonstraram uma estabilidade estacional da atividade moluscicida do produto coletado na Ilha do Governador - RJ, encontrando-se as seguintes DL90: 1,14 ppm (primavera); 1,02 ppm (outono); 1,09 ppm (inverno) e 1,07 ppm (verão) sobre Biomphalaria tenagophila de campo. Ensaios com o látex da planta coletado em Belo Horizonte e Recife, identificaram DL90 semelhantes aos da substância de referência coletada no Rio, demonstrando uma estabilidade geográfica do efeito moluscicida. Usando diluições aquosas do latex in natura, centrifugado (precipitado) e liofilizado, observou-se a estabilidade da ação moluscicida até 124 dias a temperatura ambiente (in natura) e até 736 dias, estocado em geladeira comum, entre 10 a 12ºC (liofilizado). A 5,0 ppm é 100% letal para caramujos, até 13 dias após preparada, perdendo o efeito gradativamente até estar quase inativa no 30º dia. Esta observação indicou ser o princípio ativo instável. Tais características, associadas a larga distribuição da planta, sua resistência e adaptação ao clima tropical, seu fácil cultivo, extração do látex e preparação da solução moluscicida, tornam o produto promissor para o uso em larga escala no contrôle da esquistossomose

The present study was aimed at characterising Biomphalaria species using both morphological and molecular (PCR-RFLP) approaches. The specimens were collected in 15 localities in 12 municipalities of the southern region of the state of Rio Grande do Sul, Brazil. The following species were found and identified: Biomphalaria tenagophila guaibensis, Biomphalaria oligoza and Biomphalaria peregrina. Specimens of the latter species were experimentally challenged with the LE Schistosoma mansoni strain, which showed to be refractory to infection.

Laboratory and field bioassays have confirmed the specificity of the molluscicidal activity of the Euphorbia splendens var. hislopii latex (crown of Christ) (Euphorbiaceae) over snails of the species Biomphalaria glabrata, B. tenagophila, B. straminea, B. pfeifferi and Bulinus sp. in the control of Schistosoma mansoni. In the present study, the effect of the pH variation on lethal concentration (LC90) over B. tenagophila was evaluated. Bioassays with the aqueous solutions of the latex ranging from 0.4 to 12 µl/l were adjusted for pH of 5.0; 6.0; 7.0 and 8.0, and tested in accordance with methods standardized by World Health Organization. The results obtained indicated that the minor concentration of the latex occurred at pH 6.0 (LC90 = 3.2 µl/l) and the maximum at pH 8.0 (LC90 = 10.3 µl/l). Lethal concentrations adjusted for pH 5.0 and 7.0 were 3.4 µl/l and 4,7µl/l, respectively. From the results it could be concluded that the molluscicidal toxicity was not altered when the concentrations were adjusted for pH 5.0 and 6.0, as we observed that mortality rate was 100% starting at a concentration of 2.0 µl/l, not the same for the concentrations with adjustment for pH 7.0 and 8.0.Bioensaios de laboratório e de campo têm comprovado a especificidade da ação moluscicida do látex da Euphorbia splendens var. hislopii (coroa-de-Cristo) (Euphorbiaceae) para os moluscos das espécies Biomphalaria glabrata, B. tenagophila, B. straminea, B. pfeifferi e Bulinus sp. No presente estudo foi investigado o efeito da variação do pH na concentração letal (CL90) testada para B. tenagophila. Bioensaios com soluções aquosas do látex variando de 0,4 a 12,0 µl/l foram ajustadas aos valores de pH 5,0; 6,0; 7,0 e 8,0, e testadas de acordo com os métodos padronizados pela Organização Mundial da Saúde. Os resultados obtidos indicam que a menor concentração letal do látex ocorreu em pH 6,0 (CL90 = 3,2 µl/l) e a maior em pH 8,0 (LC90 = 10,3 µl/l). As concentrações letais (LC90) ajustadas em pH 5,0 e 7,0 foram 3,4 µl/l e 4,7 µl/l, respectivamente. A partir destes dados conclui-se que a toxicidade do moluscicida não se alterou quando as concentrações foram ajustadas em pH 5,0 e 6,0, pois observou-se que a mortalidade foi de 100% a partir da concentração de 2,0 µl/l, o que não ocorreu nas concentrações com ajuste de pH 7,0 e 8,0.

Studies on eight localities on the Island of Santa Catarina revealed the presence of three species of the molluscan family Planorbidae: Biomphalaria tenagophila, Drepanotrema cimex and Biomphalaria oligoza, the first one being naturally infected by Cercaria ocellifera, a furcocercaria with morphological characteristics of Cercaria caratinguensis, and by an unknown furcocercaria. Drepanotrema cimex was infected by a furcocercaria with characteristics of C. caratinguensis and by C. macrogranulosa. No natural infection was found in B. oligoza. B. tenagophila showed no susceptibility to the experimental infection by the BH-MG strain of Schistosoma mansoni from Belo Horizonte and maintained at laboratory in B. glabrata snails. Pesquisas em oito localidades da Ilha de Santa Catarina revelaram a presença de três espécies da família Planorbidae: Biomphalaria tenagophila, Drepanotrema cimex e B. oligoza, estando a primeira naturalmente infectada por Cercaria ocellifera, furcocercária com características morfológicas de C. caratinguensis e uma furcocercária desconhecida. O segundo molusco citado, estava infectado com C. macrogranulosa e com furcocercária com características de C. caratinguensis, não sendo constatada infecção natural em B. oligoza. No processo de infecção experimental com cepa BH-MG de Schistosoma mansoni, cepa originária de Belo Horizonte e mantida em laboratório em mo lusco B. glabrata, B. tenagophila não se mostrou suscetível.

This paper describes the ecology of two species of Biomphalaria: B.glabrata and B. straminea. These species have been intensively studied in Brazil and in other countries since the 1950s. The literature in this area can be broadly subdivided into three categories, linked to three distinct historical periods: 1) an accumulated store of early studies carried out in the laboratory and in the field; 2) the development of quantitative ecological models; and 3) the development of an alternative methodology for breeding snails under seminatural conditions. Aspectos ecológicos de duas espécies brasileiras de Biomphalaria, transmissoras da esquistossomose mansônica, são discutidos no presente artigo. B. glabrata e aB. straminea têm sido intensamente estudadas no Brasil e em outros países desde a década de 50. Este artigo enfatiza três momentos que marcaram o desenvolvimento histórico de nosso conhecimento sobre a biologia destes caramujos: 1. o acervo antigo acumulado de estudos de laboratório e de campo; 2. o desenvolvimento de modelos ecológicos quantitativos; 3. o desenvolvimento de metodologia alternativa para o cultivo dos caramujos em condições seminaturais.