Estudo da composição química, toxicidade e atividade moluscicida do óleo essencial Citrus sinensis (L.) Osbeck / Study of the chemical composition, toxicity and molluscicidal activity of the essential oil Citrus sinensis (L.) Osbeck

RESUMO Determinamos a composição química e testamos a toxicidade e a atividade moluscicida do óleo essencial extraído das cascas do Citrus sinensis (L.) Osbeck. Para isso, o óleo essencial foi extraído quantitativamente por hidrodestilação. Em seguida, as quantificações de seus componentes foram realizadas por cromatografía gasosa acoplada à espectrometria de massas (CG-MS) e a toxicidade e atividade moluscicida foram testadas, respectivamente, contra Artemia salina e caramujos Biomphalaria glabrata. Os resultados mostraram que o óleo contém 81,50% de D-limoneno (constituinte principal) e 0,06% de citronelal (componente menor) e este possui atividade moluscicida com concentração letal (CL50) de 100,08 mg.L-1 e atoxicidade, com CL50 de 321,84 mg.L-1 a um nível de confiança de 95%. Portanto, o óleo é ativo contra o caramujo Biomphalariaglabrata e atóxico para outros seres vivos.

SUMMARY In this present study, we determined the chemical composition and we tested the toxicity and the molluscicidal activity of the essential oil extracted from the barks of Citrus sinensis (L.) Osbeck. For this, the essential oil was extracted quantitatively by hydrodistillation. Then, quantifications of its components were performed by gas chromatography coupled to mass spectrometry (CG-MS) and the toxicity and molluscicidal activity were tested, respectively, against Artemia salina and snails Biomphalaria glabrata. The results showed that the oil contains 81.50% of D-limonene (main constituent) and 0.06% of citronellal (minor component) and it has lethal activity (LC50) of 100.08 mg.L-1 and a toxicity, with LC50 of321.84 mg.L -1 at a 95% confidence level. Therefore, the oil is active against the snail Biomphalaria glabrata and non-toxic to other living bein.

Interaction of Biomphalaria cells in primary cultures with Schistosoma mansoni sporocysts

Abstract INTRODUCTION: Biomphalaria snails may display varying levels of susceptibility to Schistosoma mansoni infection. We have been developing an in vitro model to study the interaction between the snail and the parasite, using tissue-derived cell cultures from Biomphalaria. METHODS: The digestive gland- and kidney-derived cells from primary cultures of resistant (B. tenagophila Taim) and susceptible (B. tenagophila HM and B. glabrata BH) strains of Biomphalaria were exposed to S. mansoni sporocysts. RESULTS: S. mansoni sporocysts were surrounded and encapsulated exclusively by cells derived from the digestive gland (DG) of B. tenagophila Taim. The process was followed by a marked decrease in the number of free sporocysts in the culture medium. The morphological characteristics of DG-derived cells in culture have been described. CONCLUSIONS: Cells derived from DG (but not SK) primary cultures of B. tenagophila Taim may participate in S. mansoni sporocyst control.

Toxicity and molluscicidal activity of the essential oil Pimenta dioica against the snail Biomphalaria glabrata / Toxicidad y actividad molusccidal del aceite esencial Pimenta dioica contra el caracol Biomphalaria glabrata

This work evaluated the toxicity and molluscicidal effect of the oil extracted from Pimenta dioica leaves against the snail Biomphalaria glabrata (Say, 1818). For this, the essential oil was extracted quantitatively by hydrodistillation. Then quantifications of its components were performed by gas chromatography coupled to mass spectrometry (CG-MS) and the toxicity and molluscicidal activity were tested, respectively, against Artemia salina and snails Biomphalaria glabrata (Say, 1818). The lethal concentration (LC50) was calculated from the Reed-Muench & Pizzi methods, respectively, for toxicity and molluscicide testing. The results of the chromatographic analysis showed that the oil contains 85.67% eugenol (major constituent) and 0.88% linalool (minor component). In the toxicity evaluation, the oil was considered highly toxic with a LC50 of 14.13 mg∙L-1, in a 95% confidence interval, while the molluscicidal activity presented a lethal concentration (LC50) of 18.62. mg∙L-1 at a 95% confidence interval. Therefore, the oil is active against the snail Biomphalaria glabrata.

Este trabajo evaluó la toxicidad y el efecto molusquicida del aceite extraído de las hojas de Pimenta dioica contra el caracol Biomphalaria glabrata (Say, 1818). Para esto, el aceite esencial se extrajo cuantitativamente por hidrodestilación. Luego se realizaron cuantificaciones de sus componentes mediante cromatografía de gases acoplada a espectrometría de masas (CG-MS) y se analizaron la toxicidad y la actividad molusquicida, respectivamente, contra Artemia salina y los caracoles Biomphalaria glabrata (Say, 1818). La concentración letal (CL50) se calculó a partir de los métodos de Reed-Muench y Pizzi, respectivamente, para pruebas de toxicidad y molusquicidas. Los resultados del análisis cromatográfico mostraron que el aceite contiene un 85,67% de eugenol (constituyente principal) y un 0,88% de linalool (componente secundario). En la evaluación de toxicidad, el aceite se consideró altamente tóxico con una CL50 de 14.13 mg∙L-1, en un intervalo de confianza del 95%, mientras que la actividad molusquicida presentó una concentración letal (CL50) de 18.62. mg∙L-1 en un intervalo de confianza del 95%. Por lo tanto, el aceite es activo contra el caracol Biomphalaria glabrata.

Study on biological characteristics: reproduction and viability of Biomphalaria glabrata as an intermediate host of Schistosoma mansoni / 中国血吸虫病防治杂志

Objective To compare the difference of fertility of Biomphalaria glabrata snails between self-fertilization and cross-fertilization and to observe the circadian rhythm of laying eggs, the effect of light on laying eggs and the tolerance of the snail to water and food deficiency, so as to provide the evidence for control and elimination of B. glabrata snails in the field. Methods Under laboratory conditions, a single B. glabrata egg for self-fertilization was separated and hatched individually, and young snails were raised in different plastic boxes individually. The eggs for cross-fertilization were hatched and the young snails were fed in the same plastic box. The ability of spawn, the development of the eggs, and the number of snails growing from young to adult snails were compared between the self-fertilization and cross-fertilization. The snails were in the water under four environments, all day illumination, all day without illumination, daytime lighting and night without illumination, and daytime without illumination but night lighting. The eggs were collected and counted daily. The circadian rhythm of spawn and the effect of illumination on spawn were observed. The adult snails were divided into 6 groups and exposed to the environments with relative humidity of 0, 65%, 87% and 100%, respectively. The survival rates of the adult snails exposed to the different environments after different time were observed. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were observed. Results In the 25 °C water, the average laying egg number for 15 days per snail was (8.77 ± 16.92) eggs/snail in the self-fertilization snail. The average laying egg number for 15 days per snail was (149.71 ± 142.28) eggs/snail in the cross-fertilization snails. There was a significant difference between the self-fertilization snail and cross-fertilization snail (t = 0.999 999, P < 0.01). The hatching rate and reproductive maturation rate of the self-fertilization snails and cross-fertilization snails were 50.1% and 78.9%, and 19.3% and 3.8%, respectively, There was a significant difference (the hatching rate: χ2 = 18.18, P < 0.01, the reproductive maturation rate: χ2 = 11.83, P < 0.01) . In the natural environment of daytime with illumination and nighttime with darkness, the amount of laying 20 eggs of B. glabrata snail was (944.07 ± 392.53) eggs/day during a whole day, among them the amount of laying eggs during daytime account for 10.1% and the amount of laying eggs during nighttime account for 89.9%, and the laying egg was given priority to with the night. The above results suggested that the dark environment was conducive to B. glabrata snails to lay eggs. The above results suggested that light can promote the increase of spawning of B. glabrata. When B. glabrata was exposed to the environments with the relative humidity of 0, 65%, 87% and 100% at 25 °C, respectively, and the longest survival times of snails were 7, 70, 150 d and 100 d, respectively. In the 25 °C water, the snails could survive for 50 days without food. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were 100%, 100%, 100%, 100%, 70%, 30%, 0, 0, 0 and 0, respectively. Conclusions B. glabrata can achieve the reproductive process by cross-fertilization or self-fertilization. There is a significant difference in reproductive ability between the cross-fertilization snail and self-fertilization snail, cross-fertilization is stronger than self-fertilization, but the rate of reproduction in the self-fertilization is higher than that in the cross-fertilization. It is indicated that B. glabrata that survive after the dry season plays an important role in the maintenance of local snail populations and transmission of schistosomiasis mansoni.

Study on biological characteristics: reproduction and viability of Biomphalaria glabrata as an intermediate host of Schistosoma mansoni / 中国血吸虫病防治杂志

Objective To compare the difference of fertility of Biomphalaria glabrata snails between self-fertilization and cross-fertilization and to observe the circadian rhythm of laying eggs, the effect of light on laying eggs and the tolerance of the snail to water and food deficiency, so as to provide the evidence for control and elimination of B. glabrata snails in the field. Methods Under laboratory conditions, a single B. glabrata egg for self-fertilization was separated and hatched individually, and young snails were raised in different plastic boxes individually. The eggs for cross-fertilization were hatched and the young snails were fed in the same plastic box. The ability of spawn, the development of the eggs, and the number of snails growing from young to adult snails were compared between the self-fertilization and cross-fertilization. The snails were in the water under four environments, all day illumination, all day without illumination, daytime lighting and night without illumination, and daytime without illumination but night lighting. The eggs were collected and counted daily. The circadian rhythm of spawn and the effect of illumination on spawn were observed. The adult snails were divided into 6 groups and exposed to the environments with relative humidity of 0, 65%, 87% and 100%, respectively. The survival rates of the adult snails exposed to the different environments after different time were observed. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were observed. Results In the 25 °C water, the average laying egg number for 15 days per snail was (8.77 ± 16.92) eggs/snail in the self-fertilization snail. The average laying egg number for 15 days per snail was (149.71 ± 142.28) eggs/snail in the cross-fertilization snails. There was a significant difference between the self-fertilization snail and cross-fertilization snail (t = 0.999 999, P < 0.01). The hatching rate and reproductive maturation rate of the self-fertilization snails and cross-fertilization snails were 50.1% and 78.9%, and 19.3% and 3.8%, respectively, There was a significant difference (the hatching rate: χ2 = 18.18, P < 0.01, the reproductive maturation rate: χ2 = 11.83, P < 0.01) . In the natural environment of daytime with illumination and nighttime with darkness, the amount of laying 20 eggs of B. glabrata snail was (944.07 ± 392.53) eggs/day during a whole day, among them the amount of laying eggs during daytime account for 10.1% and the amount of laying eggs during nighttime account for 89.9%, and the laying egg was given priority to with the night. The above results suggested that the dark environment was conducive to B. glabrata snails to lay eggs. The above results suggested that light can promote the increase of spawning of B. glabrata. When B. glabrata was exposed to the environments with the relative humidity of 0, 65%, 87% and 100% at 25 °C, respectively, and the longest survival times of snails were 7, 70, 150 d and 100 d, respectively. In the 25 °C water, the snails could survive for 50 days without food. The adult snails were placed at 25 °C in the oven to remove water content from the soft body of snails. When the dehydration rates of the soft bodies achieved 10%, 20%, 30%, 40%, 50%, 52%, 55%, 57%, 60%, and 70% respectively, the survival rates of the adult snails exposed to the oven were 100%, 100%, 100%, 100%, 70%, 30%, 0, 0, 0 and 0, respectively. Conclusions B. glabrata can achieve the reproductive process by cross-fertilization or self-fertilization. There is a significant difference in reproductive ability between the cross-fertilization snail and self-fertilization snail, cross-fertilization is stronger than self-fertilization, but the rate of reproduction in the self-fertilization is higher than that in the cross-fertilization. It is indicated that B. glabrata that survive after the dry season plays an important role in the maintenance of local snail populations and transmission of schistosomiasis mansoni.

Prevalence of infection of biomphalaria glabrata by schistosoma mansoni and the risk of urban schistosomiasis mansoni in Salvador, Bahia, Brazil

Abstract INTRODUCTION: Biomphalaria glabrata is considered to be responsible for the incidence of schistosomiasis in Brazil. Therefore, surveillance of areas where schistosomiasis is prevalent is fundamental for public health planning. This study was aimed to evaluate B. glabrata populations in water bodies of the city of Salvador, determine their distribution, estimate the prevalence of Schistosoma mansoni infections, characterize shed cercariae, and identify transmission foci. METHODS: Malacological surveys were carried out in 17 water collections from Salvador. Snail species were identified based on shell and mantle characteristics. Snails were evaluated for S. mansoni infection by exposure to light and via real time polymerase chain reaction (qPCR) using S. mansoni-18S rRNA subunit specific primers. RESULTS: 1,403 B. glabrata were collected. Classical cercarial shedding indicated that 5 snails (0.4%) were positive for S. mansoni. A higher prevalence of infections was found in Horta de Saramandaia (5.5%) and Lagoa do IAT (1.9%). Non-Schistosoma larvae, such as Xiphidiocercaria, Strigeidae, Spirorchiidae and Clinostomidae, were observed in 3.2% of the snails. S. mansoni DNA was detected in 6.2% snails via qPCR. CONCLUSIONS: B. glabrata is widely distributed in Salvador, as indicated by 7 water collections associated with a risk of schistosomiasis transmission. To our knowledge, this is the first study to identify B. glabrata eliminating cercariae of Clinostomidae, Strigeidae, and Spirorchiidae in Salvador. We propose that qPCR may be employed in combination with classical cercarial shedding. Estimating S. mansoni prevalence in snails by only considering the results of light exposure method classical into account may underestimate the problem.

Studies on colonization risk and potential geographical distribution of Biom-phalaria glabrata as an intermediate host of Schistosoma mansoni in Main-land China / 中国血吸虫病防治杂志

Objective To predict the colonization risk and potential geographical distribution of Biomphalaria glabrata in the Mainland China based on the past period temperature data.Methods The survival extreme high temperatures and low tem-peratures of B.glabrata eggs,young and adult B.glabrata snails and the average effective accumulated temperature of genera-tion development were determined in laboratory conditions.The temperature data in January and July from 1955 to 2010 were collected from the national meteorological monitoring sites in the southern part of China,including Chongqing,Zhejiang,Yun-nan,Sichuan,Jiangxi,Hunan,Hainan,Guizhou,Guangdong,Guangxi and Fujian provinces(11 provinces).A database of ambient temperature related to B.glabrata was established based on the Geographic Information System(GIS).The colonization risk and potential geographical distribution of B.glabrata in the southern part of China were analyzed and predicted by ArcGIS 10.1 software.Results The half lethal low temperatures of B.glabrata eggs,young and adult B.glabrata snails were 6.80,6.34℃ and 6.60℃ respectively;the half lethal high temperatures of B.glabrata eggs,young and adult B.glabrata snails were 35.99,33.59℃ and 32.20℃,respectively.The developmental threshold temperature was 7.16℃;the average effective accumu-lated temperature of generation development was(1 970.07 ± 455.10)days-degree.The GIS overlay analysis of the half lethal low and high temperatures of B.glabrata showed that the local temperature conditions in all Hainan and part regions in Yunnan,Guangxi,Guangdong and Fujian were conformed to the survival temperature of B.glabrata snails.The regions,where the aver-age effective accumulated temperature was more than the average effective accumulated temperature of generation development of B.glabrata,were Guangdong and Hainan,and part regions of other 9 provinces.The overlay analysis of GIS maps of the sur-vival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated tem-perature of generation development in 2010 showed that the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian were potential geographical distribution regions of colonization risk of B.glabrata.The overlay analysis of GIS maps of the survival extreme high temperatures and low temperatures of B.glabrata with the GIS map of the average effective accumulated temperature of generation development from 1955 to 2010 showed that the potential geographical distribution re-gions of B.glabrata was expanding from the whole region of Hainan and part regions of Guangdong in 1955 to the whole region of Hainan and part regions of Guangdong,Guangxi,Yunnan and Fujian in 2010.Conclusions If B.glabrata snails were intro-duced into the Mainland China,the potential geographical distribution regions would be the whole region of Hainan and part re-gions of Guangdong,Guangxi and Yunnan.The changes of risk range and risk intensity present the trends of expanding and in-creasing from the south to the north gradually.

Quantitative determination of biogenic amine from Biomphalaria glabrata nervous system by UPLC MS/MS / 中国血吸虫病防治杂志

Objective To establish a method for the quantitative determination of serotonin and dopamine in the nervous sys-tem of Biomphalaria glabrata by using ultra high performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC MS/MS). Methods The B.glabrata nervous system was broken in the pure methanol solution after obtaining it by dis-secting with microscope.Then,the supernatant containing the target substance after twice high speed centrifugation was got.The extraction was separated on an ACQUITY UPLC BEH Amide column with Waters TQ-XS series mass spectrometry detector, with ESI source and positive electrospray ionization mode when the machine testing. Results The detection limit of serotonin was 0.03 ng/ml and the limit of quantification was 0.1 ng/ml.The detection limit of dopamine was 0.05 ng/ml and the limit of quantification was 0.15 ng/ml.The recoveries of serotonin ranged from 90.68% to 94.72% over the range of 1 to 40 ng/ml.The re-coveries of dopamine ranged from 91.68% to 96.12% over the range of 1.0 ng/ml to 40 ng/ml. Conclusion The established UPLC MS/MS method is simple,stable and reproducible.It can be used for the quantitative analysis of serotonin and dopamine in the nervous system of B.glabrata snails.

Distribuição dos moluscos transmissores da esquistossomose no município endêmico de São Bento, Maranhão, Brasil / Distribution of mollusks that transmit schistosomiasis in the endemic municipality of São Bento, Maranhão, Brazil

Neste estudo, objetivou-se mapear os criadouros de Biomphalaria spp., transmissoras da esquistossomose mansoni, presentes no município de São Bento, localizado na região da Baixada Maranhense, área na qual esta doença é endêmica. Foram visitados 16 dos 22 bairros existentes na cidade durante o período de agosto de 2012 a julho de 2013. Os caramujos foram coletados com auxílio de conchas de captura e pinças, armazenados e transportados para o Laboratório de Parasitologia Humana da Universidade Estadual do Maranhão, em São Luís, onde foram acondicionados em aquários de vidro e alimentados com folhas de alface. Os moluscos foram submetidos à análise parasitológica à procura de estágios larvais de Schistosoma mansoni e identificados pela conquiliologia e por meio de dissecções. Em 18 criadouros mapeados foram obtidos 1.195 exemplares de Biomphalaria glabrata e de B. straminea. Nenhum molusco eliminou cercárias de S. mansoni. Considerando os resultados obtidos e os aspectos epidemiológicos relacionados à transmissão da esquistossomose, o mapeamento das espécies vetoras no município permitirá a localização e identificação dos criadouros, o que poderá auxiliar substancialmente os serviços de saúde locais nas atividades de vigilância e controle da esquistossomose, além de nortear futuros estudos epidemiológicos sobre a esquistossomose mansoni na região da Baixada Maranhense

EVALUATION OF THE MOLLUSCICIDAL POTENTIAL OF HYDROALCOHOLIC EXTRACTS OF Jatropha gossypiifolia Linnaeus, 1753 ON Biomphalaria glabrata (Say, 1818) / Avaliação do potencial moluscicida de extratos hidroalcoólicos do caule, folhas e frutos de Jatropha gossypiifolia Linnaeus, 1753 em Biomphalaria glabrata (Say, 1818)

The action of extracts from the stem, leaves, and fruit of Jatropha gossypiifolia on Biomphalaria glabrata was studied by analyzing survival, feeding capacity and oviposition ability. The extracts were obtained by macerating the plant parts in 92% ethanol, which were then evaporated until a dry residue was obtained and phytochemically studied. The molluscicidal activity on B. glabrata was investigated using the procedures recommended by WHO (1965). The amount of food ingested and oviposition were measured during each experiment. The extract of leaves from J. gossypiifolia was shown to be a strong molluscicidal agent, causing 100% mortality of B. glabrata, even in the lowest concentration tested, of 25 ppm. Regarding the fruit extract, there was variation in the mortality, depending on the concentration used (100, 75, 50 and 25 ppm). The snails that were in contact with the fruit extract had significant reduction in feeding and number of embryos in comparison to the control. The stem extract did not present molluscicidal activity nor had any influence on the feeding and oviposition abilities of B. glabrata, in the concentrations tested. In conclusion, the extracts of leaves and fruits of J. gossypiifolia investigated in this work show molluscicidal effect and may be sources of useful compounds for the schistosomiasis control.

Estudou-se a ação dos extratos do caule, folhas e frutos de Jatropha gossypiifolia (Pinhão-roxo) sobre Biomphalaria glabrata analisando a sobrevivência, capacidade alimentar e de oviposição. Os extratos foram obtidos pela maceração das partes do vegetal em álcool etílico 92%, evaporados até obter-se um resíduo seco e estudados fitoquimicamente. A atividade moluscicida em B. glabrata seguiu os procedimentos recomendados pela WHO (1965). A medida de quantidade de alimento ingerido e a oviposição foi realizada durante cada experimento. O extrato das folhas de J. gossypiifolia mostrou-se um forte agente moluscicida, promovendo 100% de mortalidade de B. glabrata mesmo na menor concentração testada, 25 ppm. Com o extrato dos frutos houve variação na mortalidade, de acordo com a concentração utilizada (100, 75, 50 e 25 ppm). Os caramujos em contato com o extrato dos frutos apresentaram quando comparado ao controle uma diminuição significativa nos comportamentos alimentares e de número de embriões. O extrato do caule não apresentou atividade moluscicida e nenhuma influência sobre a capacidade alimentar e de oviposição de B. glabrata nas concentrações testadas. Em conclusão, os extratos de folhas e frutos de J. gossypiifolia investigados neste trabalho apresentam efeito moluscicida e possivelmente podem ser fontes de compostos no controle da esquistossomose.

OVICIDAL EFFECT OF PIPERACEAE SPECIES ON Biomphalaria glabrata, Schistosoma mansoni HOST / Efeito ovicida de espécies de Piperaceae em Biomphalaria glabrata, hospedeiro do Schistosoma mansoni

SUMMARY Schistosomiasis is a neglected disease with public health importance in tropical and subtropical regions. An alternative to the disease control is the use of molluscicides to eliminate or reduce the intermediate host snail population causing a reduction of transmission in endemic regions. In this study nine extracts from eight Piperaceae species were evaluated against Biomphalaria glabrata embryos at blastula stage. The extracts were evaluated in concentrations ranging from 100 to 10 mg/L. Piper crassinervium and Piper tuberculatum extracts were the most active (100% of mortality at 20 mg/L and 30 mg/L respectively). .

RESUMO A esquistossomose é uma doença negligenciada de importância para a saúde pública em regiões tropicais e subtropicais. Uma alternativa para o controle da doença é o uso de moluscicidas para eliminar ou reduzir a população de caramujo hospedeiro, acarretando uma redução da transmissão da doença nas regiões endemicas. Neste estudo, nove extratos vegetais provenientes de oito espécies de Piperaceae foram expostos a embriões de Biomphalaria glabrata no estágio de blástula. Os extratos foram avaliados em concentrações que variaram entre 100 e 10 mg/L, sendo Piper crassinervium e Piper tuberculatum os extratos mais ativos (100% de mortalidade a 20 mg/L e 30 mg/L respectivamente). .

Efecto de los microorganismos acuáticos (rotífera y ciliata) sobre la emisión de cercarias de Schistosoma mansoni, por Biomphalaria glabrata en el laboratorio / Effect of aquatic organisms (rotifers and ciliate) on the issuance of Schistosoma mansoni larvae by Biomphalaria glabrata maintained in laboratory

Los rotíferos y ciliados son microorganismos que cohabitan con B. glabrata, y en el caracol infectado comparten espacio con el parásito S. mansoni, agente causal de la esquistosomosis. La experiencia con crías en cautiverio sugiere que la presencia de tales microorganismos puede afectar la evolución del parásito en el caracol, debido a competencia por espacio y nutrientes. En base a esto se evaluó el efecto de los rotíferos y ciliados, sobre la emisión de cercarias de S. mansoni por el molusco B. glabrata mantenida en cautiverio. En los experimentos se emplearon cinco grupos de 10 caracoles infectados con 10 miracidios de S. mansoni, los cuales, se colocaron en recipientes plásticos, con: (a) 87500 rotíferos y 25000 Paramecium sp, (b) 27000 rotíferos y 54000 Paramecium sp, (c) 800000 rotíferos, (d) 4500 Paramecium sp y rotíferos, respectivamente y (e) el grupo control de infección se mantuvo sin rotíferos y ciliados. Se demostró un efecto de inhibición en la emisión de las cercarias de S. mansoni en presencia de rotíferos y Paramecium sp, dependiente de la cantidad de organismos presentes. El porcentaje de inhibición en la emisión de las cercarias de S. mansoni se relacionó con la presencia de un gran número de rotíferos. El presente trabajo constituye el primer hallazgo que sugiere que organismos de los phyllum Rotifera y Ciliophora podrían ser empleados como control biológico de la infección por S. mansoni.

The rotifers and ciliates are microorganisms that coexist with B. glabrata, Inside tissues normally infected by S. mansoni in the snails. the causative agent of schistosomiasis. The captive breeding experience suggests that the presence of such microorganisms can affect the evolution of the parasite in the snail, because competition for space and nutrients. The effect of rotifers and ciliates in the release of cercariae of S. mansoni by the mollusc B. glabrata maintained in captivity. The experimental setting was constituted by five groups of snails (n=10) infected with 10 miracidia from S. mansoni, which were placed in plastic containers with (a) 87500 25000 rotifers and Paramecium sp, (b) 27000 54000 rotifers and Paramecium sp, (c) 800000 rotifers, (d) Paramecium sp 4500 and the same number of rotifers and (e) infection control group remained rotifers and ciliates. It was possible to observe an number-dependent inverse correlation between the release of cercaria from S. mansoni and the number of rotifers and Paramecium sp. Used in this study. Particularly, the percentage of inhibition was strongly associated with the presence of large numbers of rotifers. To date, these are the first findings suggesting that microorganisms from the genus ciliata, subphylum Crustacea, are capable of regulating S. mansoni lyfe cycle progression in the snail stage, therefore could be potentially used as biological controls for the infection caused by S. mansoni.

Schistosomiasis mansoni in urban Northeast Brazil: influence of rainfall regime on the population dynamics of Biomphalaria sp.

Introduction Our objective was to evaluate the influence of rainfall regime on the population dynamics of Biomphalaria in a potential urban focus of schistosomiasis in Aracaju, Brazil, during 2009-2010. Methods Snails were collected monthly and were counted, measured and identified; the level of infection and fecal contamination at the sampling sites was determined; rainfall data were obtained. Results High levels of fecal contamination were observed, and the abundance of Biomphalaria glabrata increased during the rainy and post-rainy seasons. The snails' size was variable, and infected snails were identified independently of rainfall. Conclusions These results provide evidence of anthropogenic and climate interference in an urban focus of schistosomiasis in the Aracaju metropolitan area. .

The significance of the amoebocyte-producing organ in Biomphalaria glabrata

In molluscs, internal defence against microorganisms is performed by a single cell type, i.e., the haemocyte or amoebocyte. The origin of these cells in Biomphalaria glabrata was initially thought to be localised within the vasculo-connective tissue. More recently, origin from a single organ, termed the amoebocyte-producing organ (APO), has been postulated based on the occurrence of hyperplasia and mitoses during Schistosoma mansoni infection. The present investigation represents a histological, immuno-histochemical and ultra-structural study of the B. glabrata APO, whereby histological identification was facilitated by means of collecting epithelial basophilic cells. These cells were comprised of single-cell layers that cover a portion of the stroma, which contains many small, round cells and haemolymph sinuses, as well as a small area of the pericardial surface of the reno-pericardial region. On occasion, this epithelial component vaguely resembled the vertebrate juxtaglomerular apparatus, which reinforces its presumed relationship to the kidney. Both in normal and infected molluscs, mitoses were only occasionally found. The present quantitative studies failed to demonstrate the presence of APO cellular hyperplasia, either in normal or schistosome-infected B. glabrata. Conversely, several structural details from the APO region in B. glabrata were found to be consistent with the hypothesis that the APO is a filtration organ, i.e., it is more closely related to the kidney rather than the bone marrow, as has been suggested in the literature.

A Mobilização do cálcio em biomphalaria glabrata exposta a diferentes quantidades de carbonato de cálcio / Calcium mobilization in biomphalaria glabrata exposed to different quantities of calcium carbonate

O cálcio é essencial na vida dos moluscos, pois está relacionado com a formação da concha e com vários processos metabólicos fundamentais para manter a sua homeostase. O objetivo deste trabalho foi verificar a mobilização do cálcio na hemolinfa e na concha de Biomphalaria glabrata exposta a diferentes soluções de carbonato de cálcio. Para este estudo, foram utilizados caramujos com 60 dias de vida, distribuídos em cinco grupos, quatro expostos a diferentes soluções (20, 40, 60 e 80mg/L) de carbonato de cálcio e um controle. O tempo total de exposição foi de 45 dias. Quinzenalmente, os caramujos eram sacrificados por meio de punção cardíaca para extração da hemolinfa. A concentração de cálcio na hemolinfa foi determinada usando-se kits de diagnóstico (Doles Reagentes) e o conteúdo de cálcio nas conchas, pelo método de volumetria de complexação modificada. Os resultados demonstraram que houve aumento de cálcio na hemolinfa e diminuição de cálcio na concha aos 15 dias de exposição a 20mg/L de carbonato de cálcio. Nos demais grupos expostos, verificou-se que a concentração de cálcio na hemolinfa é inversamente proporcional à quantidade de cálcio na concha. Concluiu-se que, em moluscos expostos a diferentes quantidades de cálcio, ocorre uma mobilização frequente do cálcio na hemolinfa e na concha de acordo com a quantidade de cálcio disponível.

Calcium is essential to mollusk’s life, because is associated with shell formation and metabolic processes that are essential to maintain their homeostasis. The aim of this work was to verify the mobilization of calcium in the haemolymph and shell of Biomphalaria glabrata (strain BH) exposed to different calcium carbonateconcentrations. Sixty days old snails were used for this study, distributed in five groups: four groups exposed to different concentrations (20, 40, 60, 80 mg/L) of calcium carbonate and one control group. The exposition time was forty-five days. Fortnightly, the snails were sacrificed by cardiac puncture for haemolymph extraction. The concentration of calcium was determined in the haemolymph, using diagnosis kits (Doles Reagentes®) and for the calcium content in the shell,a modified volumetric method of complexing was employed. The results showed an increase of the calcium content in haemolymph and a decrease in shell of snails exposed to 15 days of 20mg/L of calcium carbonate. In the other exposed groups, the calcium concentration in the haemolymph was inversely proportional to the amountof calcium in the shell. We conclude that in snails exposed to different amounts ofcalcium, mobilization in the hemolymph and in the shell occurs according to theamount of calcium available.

Schistosoma mansoni: a method for inducing resistance to praziquantel using infected Biomphalaria glabrata snails

To elucidate the mechanisms of antischistosoma resistance, drug-resistant Schistosoma mansoni laboratory isolates are essential. We developed a new method for inducing resistance to praziquantel (PZQ) using successive drug treatments of Biomphalaria glabrata snails infected with S. mansoni. Infected B. glabrata were treated three times with 100 mg/kg PZQ for five consecutive days with a one-week interval between them. After the treatment, the cercariae (LE-PZQ) produced from these snails and the LE strains (susceptible) were used to infect mice. Forty-five days after infection, mice were treated with 200, 400 or 800 mg/kg PZQ. Thirty days post-treatment, we observed that the mean number of worms recovered by perfusion was significantly higher in the group of mice infected with the LE-PZQ isolate treated with 200 and 400 mg/kg in comparison to the LE strain with the same treatment. Moreover, there was a significant difference between the ED50 (effective dose required to kill 50 percent of the worms) of the LE-PZQ isolate (362 mg/kg) and the LE strain (68 mg/kg). In the in vitro assays, the worms of the LE-PZQ isolate were also less susceptible to PZQ. Thus, the use of infected snails as an experimental model for development of resistance to S. mansoni is effective, fast, simple and cheap.

Prevalência da esquistossomose num povoado do Município de Tutóia, Estado do Maranhão / Schistosomiasis prevalence in Tutóia village, Maranhão, Brazil

INTRODUÇÃO: A esquistossomose mansônica é uma patologia endêmica dos países subdesenvolvidos ou em desenvolvimento. O objetivo deste trabalho foi definir a prevalência da esquistossomose no povoado de Bom Gosto em Tutóia, Maranhão em 2008 e detectar a ocorrência do hospedeiro intermediário. MÉTODOS: Foi realizado um levantamento dos dados das amostras de fezes analisadas pela Secretaria de Saúde Municipal e Fundação Nacional de Saúde. Em seguida, foram coletados e analisados 60 caramujos. A análise dos moluscos foi feita pelo processo de esmagamento. Quanto aos sedimentos fecais, usou-se o método de Kato-Katz. RESULTADOS: De acordo com dados da Secretaria de Saúde Municipal e FUNASA, a prevalência da esquistossomose mansônica no povoado é de 3,2 por cento. Os 60 caramujos são da espécie Biomphalaria glabrata, e cinco (8,3 por cento) encontravam-se parasitados por Schistosoma mansoni. CONCLUSÕES: O povoado Bom Gosto é uma região de baixa prevalência da esquistossomose mansônica. A área investigada tem todos os componentes da cadeia epidemiológica de S. mansoni, explicando a ocorrência da doença na região.

INTRODUCTION: Schistosomiasis mansoni is an endemic disease in underdeveloped or developing countries. The study aimed to define schistosomiasis prevalence in Bom Gosto village, Tutóia, Maranhão, in 2008 and detect intermediate host occurrence. METHODS: A survey of data from stool samples examined by the Municipal Department of Health and National Health Foundation was conducted. Next, 60 snails were collected and analyzed. Mollusk analysis was achieved by the crushing process. The Kato-Katz method was used to evaluate fecal sediment. RESULTS: According to data from the Municipal Department of Health and FUNASA, schistosomiasis prevalence in the village was 3.2 percent. The 60 snails were identified as Biomphalaria glabrata and five (8.3 percent) were parasitized by Schistosoma mansoni. CONCLUSIONS: The Bom Gosto village is a low prevalence region of schistosomiasis mansoni. The study area has all the components of the epidemiological chain of S. mansoni, which explains the occurrence of disease in the region.

Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass) and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, especially from the third week onward. The utilisation of latex as a molluscicide to control the population of infected B. glabrata selectively is proposed.

The effect of early infection with Echinostoma paraensei on the interaction of Schistosoma mansoni with Biomphalaria glabrata and Biomphalaria tenagophila

Infection caused by the trematode Echinostoma paraensei has been shown to interfere in the natural resistance to infection by Schistosoma mansoni. Biomphalaria glabrata is susceptible to infection, while Taim isolate Biomphalaria tenagophila is resistant to infection by S. mansoni. These two snail species were assessed for infection with E. paraensei two days after exposure to S. mansoni miracidia. The number of B. tenagophila and B. glabrata infected with E. paraensei was lower in co-infected group, suggesting an antagonistic relationship. B. glabrata showed an increase in its susceptibility to S. mansoni, whereas B. tenagophila maintained its refractoriness to S. mansoni infection. Weekly comparisons made between the E. paraensei cercariae released from B. tenagophila and B. glabrata mono-infected snails revealed no quantitative differences. In contrast, S. mansoni cercariae released were higher in the B. glabrata co-infected group. Mortality rates were significantly greater in both species pertaining to co-infected group and unexpected mortalities were also observed in B. tenagophila exposed only to S. mansoni miracidia. Our study revealed that the B. tenagophila Taim isolate is susceptible to E. paraensei infection, although infection did not alter its resistance to S. mansoni infection.

Evaluation of a linear spectral mixture model and vegetation indices (NDVI and EVI) in a study of schistosomiasis mansoni and Biomphalaria glabrata distribution in the state of Minas Gerais, Brazil

This paper analyses the associations between Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) on the prevalence of schistosomiasis and the presence of Biomphalaria glabrata in the state of Minas Gerais (MG), Brazil. Additionally, vegetation, soil and shade fraction images were created using a Linear Spectral Mixture Model (LSMM) from the blue, red and infrared channels of the Moderate Resolution Imaging Spectroradiometer spaceborne sensor and the relationship between these images and the prevalence of schistosomiasis and the presence of B. glabrata was analysed. First, we found a high correlation between the vegetation fraction image and EVI and second, a high correlation between soil fraction image and NDVI. The results also indicate that there was a positive correlation between prevalence and the vegetation fraction image (July 2002), a negative correlation between prevalence and the soil fraction image (July 2002) and a positive correlation between B. glabrata and the shade fraction image (July 2002). This paper demonstrates that the LSMM variables can be used as a substitute for the standard vegetation indices (EVI and NDVI) to determine and delimit risk areas for B. glabrata and schistosomiasis in MG, which can be used to improve the allocation of resources for disease control.