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Sample records for cercaria

  1. Studies on Cercariae from Kuwait Bay. XI. Description and surface topography of Cercaria kuwaitae XI sp.n. (Digenea: Echinostomatidae

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    Abdul-Salam J

    1999-01-01

    Full Text Available A new echinostome cercaria, Cercaria kuwaitae XI sp.n., from the prosobranch gastropod Cerithidea cingulata (Gmelin from Kuwait Bay is described. The new cercaria is characterized by 23 collar spines and primary excretory tubules with distinct diverticula. The cercaria encysts in the snail host and is similar to those of Acanthoparyphium sp. The surface topography of the redia, cercaria and metacercarial cyst wall is studied by scanning electron microscopy. This is the first echinostome cercaria to be recorded in a gastropod from the Arabian Gulf region.

  2. Schistosoma mansoni cercariae exploit an elastohydrodynamic coupling to swim efficiently

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    Krishnamurthy, Deepak; Bhargava, Arjun; Prakash, Manu

    2016-01-01

    The motility of many parasites is critical for the infection process of their host, as exemplified by the transmission cycle of the blood fluke Schistosoma mansoni. In their human infectious stage, immature, submillimetre-scale forms of the parasite known as cercariae swim in freshwater and infect humans by penetrating through the skin. This infection causes Schistosomiasis, a parasitic disease that is comparable to malaria in its global socio-economic impact. Given that cercariae do not feed and hence have a finite lifetime of around 12 hours, efficient motility is crucial for the parasite's survival and transmission of Schistosomiasis. However, a first-principles understanding of how cercariae swim is lacking. Via a combined experimental, theoretical and robotics based approach, we demonstrate that cercariae propel themselves against gravity by exploiting a unique elastohydrodynamic coupling. We show that cercariae beat their tail in a periodic fashion while maintaining a fixed flexibility near their poster...

  3. Morphological Specifications of the Bird Schistosome Cercariae and Surface Carbohydrates as Receptors for Lectins

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    I Moebedi

    2007-04-01

    Full Text Available Background: To determine the morphological specifications of the bird schistosomes cercaria from Lymnaea gedrosiana and to detect the surface carbohydrates as receptors for host lectins in the host-parasite relationship systems such as avian schistosomiasis and human cercarial dermatitis. Methods: One hundred ninety two snails collected from Dezful areas in Khuzestan Province, in the south west of Iran, during 2005-2006 were examined for cercariae using shedding and crushing methods. In addition, surface carbohydrates on the cercariae were detected by lentil (Lens culinaris lectins. Results: From the total number of Lymnaea gedrosiana, which examined for bird schistosomes cercaria, 9(4% snails were found to be infected with furcocercus cercaria of the bird schistosomes (probably Gigantobilharzia sp.. Mannose monosaccharide CH2OH (CHOH4CHO as surface carbohydrate was also detected on the cercariae. Conclusion: Mannose carbohydrate on these cercariae may be used as receptor by lectins.

  4. The deadly swimming of Cercariae: an unusual Stokesian swimmer

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    Prakash, Manu; Krishnamurthy, Deepak

    2014-11-01

    Schistosomiasis, also known as Bilharzia, is a Neglected Tropical Disease (NTD) caused by a parasitic Trematode blood fluke worm. In terms of socio-economic and public health impact, Schistosomiasis is second only to Malaria as the most devastating parasitic disease in tropical countries; with roughly 200 million people infected at any time world-wide and up to 200,000 deaths every year. The infectious form of the parasite, known as Cercariae, emerge from snails into freshwater and infect humans by directly burrowing into the skin. Thus, anyone in contact with infected waters is at risk, which mostly includes children. By establishing a safe experimental means of studying the Cercariae in our lab, we report here their unusual swimming dynamics which include both head-first and tail-first swimming modes. These swimming modes are crucial for the chemotactic activity of Cercariae which allows them to seek out and burrow into human skin. By experimental and analytical means, we demonstrate that Cercariae break symmetry and achieve locomotion at small Reynolds number differently when compared to well-known methods involving traveling waves in the flagellum or chiral beating. Although they utilize the well-known drag anisotropy of a slender body in Stokes flow, the geometry and kinematics of their propulsion mechanism is novel. Based on these results, we propose a new kind of simple Stokesian swimmer (T-joint swimmer) in an attempt to explain the evolutionary advantages of this novel swimming mechanism. Using the above physical insights from a biological and global-health standpoint, we explore ways to hinder the chemotactic capabilities of this parasite.

  5. Production of marine trematode cercariae: a potentially overlooked path of energy flow in benthic systems

    DEFF Research Database (Denmark)

    Thieltges, David W.; de Montaudouin, Xavier; Fredensborg, Brian;

    2008-01-01

    . We use published data on rates at which trematodes produce free-swimming infective larvae (cercariae) that are released from their gastropod intermediate hosts to investigate patterns in cercarial output as a function of different variables, and to calculate the annual production of cercariae...... of cercariae, and was influenced by the type of downstream host sought by cercariae, being highest when this host was a vertebrate. Our estimates of annual cercarial production (kJ m-2 yr-1), which take into account the density of infected snails in the habitat, were within the range of production values...

  6. Prevalence of Cercariae Infection in Lymnaea auricularia (Linnaeus, 1758 in NorthWest of Iran

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    Abbas Imani-Baran

    2011-06-01

    Full Text Available The pond snail Lymnaea auricularia serves as an intermediate host for many digenian species. In West Azerbaijan province, northwestern Iran, the cercariae infection investigation was undertaken in L. auricularia from May to November 2010. Of 6759 collected Lymnaeid snails, 370(5.5% L. auricularia snails were identified. Cercariae infection was found in a number of 276 (74.56 % snails. The results showed that removed cercariae from L. auricularia belonged to Echinostomcercariae (96.38 % and Furcocercariae (3.62 % which were found in two out of 28 sites during the course of study. In summer and fall, the highest prevalence of cercariae infection was recorded for both identified cercariae. It is concluded that L. auricularia could be an important intermediate host of large group digenian trematodes in the region, which is necessary to take consideration in the control program of trematode infection.

  7. Substratum preferences in two notocotylid (Digenea, Notocotylidae) cercariae from Hydrobia ventrosa at the White Sea

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    Gonchar, Anna; Galaktionov, Kirill V.

    2016-07-01

    Notocotylids are digeneans with a two-host life cycle. Their cercariae encyst on underwater substrata, and final hosts (mostly water birds) get infected by consuming encysted metacercariae. The aim of this study was to assess whether notocotylid cercariae have encystment substratum preferences. We used Cercaria Notocotylidae sp. No 11 Deblock, 1980 (presumably Paramonostomum alveatum Mehlis 1846) and C. Notocotylidae sp. No 12 Deblock, 1980 associated with mudsnails Hydrobia ventrosa at the White Sea. Three series of experiments were performed in which distribution of cysts across different combinations of substrata was measured. The results suggest that C. Notocotylidae sp. No 11 cercariae encyst almost exclusively on the leaves of green plants without any plant species preferences. C. Notocotylidae sp. No 12 cercariae use shells of living molluscs and plant substrata equally often but avoid empty shells. These preferences are probably adapted to the feeding habits of the final hosts and this may enhance the transmission of the studied notocotylid species. Mechanisms of the observed preferences might be associated with the ability of cercariae to recognize substrata features: either chemical cues or surface structure. Substratum selectivity in cercariae is considered as a first step towards downward incorporation of the second intermediate host into the life cycle.

  8. Kinetics of the cercaria-schistosomulum transformation in vivo

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    A. L. Melo

    1985-03-01

    Full Text Available Sitice most studies on the cercaria-schistosomulum transformation have been carried out in vitro, the authors used the inoculation ofcercariae into the peritoneal cavity of mice tofollow the steps involved in this progressive adaptation of cercarie to the vertebmte host. The main conclusions were: 1. Most cercariae reach the schistosomular stage between 90-120 min after intraperitoneal inoculation. 2. Changes usuallystart with detachment of the tail followed by loss, rupture or changes of the glycocalix. 3. After 120 min most larvae loss their tails and present water sensitivity. 4. Acetabular grands depletion usually does not occur in cercaria-shistosomulum changes in the peritoneal cavity of mice. These steps differ in some way from those described in the kinetics of the in vitro observations performed by other investigators, and is more like those described in the penetration in the skin of living vertebrates.Uma vez que a maioria dos estudos da transformação cercária-esquistossômulo têm sido realizados in vitro, os autores usaram a inoculação de cercárias na cavidade peritoneal de camundongos para seguir as etapas envolvidas nesta adaptação progressiva das larvas ao hospedeiro vertebrado. conclusões principais foram: 1. A maioria das cercárias atinge 0 estádio de esquistossômulo entre 90 - 120 minutos após a inoculação intraperitoneal. 2. As modificações usualmente são iniciadas com a perda da cauda, seguidas pela perda, ruptura ou modificações do glicocálice. 3. Após 120 minutos do inóculo, a maioria das larvas perde sua cauda e apresenta intolerância à água. 4. A depleção das glândulas acetabulares habitualmente não ocorre durante o processo de transformação cercária-esquistossômulo, na cavidade peritoneal do camundongo. Os resultados da inoculação intraperitoneal em camundongos aproximam-se mais dos achados da penetração da cercária na pele de hospedeiros vertebrados, e diferem, em parte, das

  9. Protein kinase A signalling in Schistosoma mansoni cercariae and schistosomules.

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    Hirst, Natasha L; Lawton, Scott P; Walker, Anthony J

    2016-06-01

    Cyclic AMP (cAMP)-dependent protein kinase/protein kinase A regulates multiple processes in eukaryotes by phosphorylating diverse cellular substrates, including metabolic and signalling enzymes, ion channels and transcription factors. Here we provide insight into protein kinase A signalling in cercariae and 24h in vitro cultured somules of the blood parasite, Schistosoma mansoni, which causes human intestinal schistosomiasis. Functional mapping of activated protein kinase A using anti-phospho protein kinase A antibodies and confocal laser scanning microscopy revealed activated protein kinase A in the central and peripheral nervous system, oral-tip sensory papillae, oesophagus and excretory system of intact cercariae. Cultured 24h somules, which biologically represent the skin-resident stage of the parasite, exhibited similar activation patterns in oesophageal and nerve tissues but also displayed striking activation at the tegument and activation in a region resembling the germinal 'stem' cell cluster. The adenylyl cyclase activator, forskolin, stimulated somule protein kinase A activation and produced a hyperkinesia phenotype. The biogenic amines, serotonin and dopamine known to be present in skin also induced protein kinase A activation in somules, whereas neuropeptide Y or [Leu(31),Pro(34)]-neuropeptide Y attenuated protein kinase A activation. However, neuropeptide Y did not block the forskolin-induced somule hyperkinesia. Bioinformatic investigation of potential protein associations revealed 193 medium confidence and 59 high confidence protein kinase A interacting partners in S. mansoni, many of which possess putative protein kinase A phosphorylation sites. These data provide valuable insight into the intricacies of protein kinase A signalling in S. mansoni and a framework for further physiological investigations into the roles of protein kinase A in schistosomes, particularly in the context of interactions between the parasite and the host. PMID:26777870

  10. Delayed tail loss during the invasion of mouse skin by cercariae of Schistosoma japonicum.

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    Wang, Ting; Fang, Zheng-Ming; Lei, Jia-Hui; Guan, Fei; Liu, Wen-Qi; Bartlett, Ann; Whitfield, Phil; Li, Yong-Long

    2012-02-01

    A traditional assumption is that schistosome cercariae lose their tails at the onset of penetration. It has, however, recently been demonstrated that, for Schistosoma mansoni, cercarial tails were not invariably being shed as penetration took place and a high proportion of tails entered human skin under experimental conditions. This phenomenon was termed delayed tail loss (DTL). In this paper, we report that DTL also happens with S. japonicum cercariae during penetration of mouse skin. It occurred at all cercarial densities tested, from as few as 10 cercariae/2·25 cm(2) of mouse skin up to 200 cercariae. Furthermore, it was demonstrated that there was a density-dependent increase in DTL as cercarial densities increased. No such density-dependent enhancement was shown for percentage attachment over the same cercarial density range.

  11. New insights into the reaction of Schistosoma mansoni cercaria to the human complement system.

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    Da'dara, Akram A; Krautz-Peterson, Greice

    2014-10-01

    Schistosomes are parasitic worms that have a complex life cycle. The larval stage cercaria, infectious to mammals, is described as highly susceptible to the complement system, largely due to the glycocalyx that covers the cercarial membrane. In an attempt to have a more complete understanding of cercaria reaction to the complement system, three different approaches were used. Live cercariae exposed to normal human serum (NHS) as source of complement factors were assessed for (i) membrane attack complex (MAC) deposition on the parasite surface, (ii) cercaria survival rate by Hoechst staining of parasite DNA, and (iii) transformation into schistosomula by detection of the glucose transporter protein 4 (SGTP4), a marker for new tegument formation. We found that 82-95% of cercariae directly exposed to NHS for 18 h were viable and retained their ability to shed the glycocalyx, suggesting minimal tegument damage. In contrast, inhibition of glycocalyx shedding using eserine caused significant MAC binding and parasite death. Culturing complement-exposed cercariae to measure long-term survival showed that more parasites died over time, reaching a survival rate of 18-31% by day 6 in culture. The reason for this slow death is unknown, but the surviving parasites were able to form a new tegument as shown by detection of SGTP4 on the parasite surface. Furthermore, we found that complement activation significantly damaged the acetabular gland ducts and lysed secretory vesicles released by transforming cercariae. These findings should contribute for future in vivo studies of the effects of the complement system in skin migrating cercariae.

  12. Cockle infection by Himasthla quissetensis - I. From cercariae emergence to metacercariae infection

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    de Montaudouin, Xavier; Blanchet, Hugues; Desclaux-Marchand, Céline; Lavesque, Nicolas; Bachelet, Guy

    2016-07-01

    The European cockle (Cerastoderma edule) is an exploited bivalve along the North-Eastern Atlantic semi-sheltered ecosystems. Its population dynamics are driven by numerous environmental factors, including parasitism, particularly by trematodes. The complex life cycle of trematodes includes a free living stage (cercaria) between the first (a mollusk) and the second (an invertebrate or a vertebrate) intermediate hosts. Taking the example of Himasthla quissetensis, a dominant trematode in Arcachon Bay (France) utilizing Nassarius reticulatus as first intermediate host and the cockle as second intermediate host, we investigated the correlation between cockle infection and cercariae emergence by N. reticulatus, including the role of water temperature and light. Experimental and field data provided evidence that cercariae emergence from N. reticulatus took place during the night and for water temperature comprised between 15 °C and 22 °C (optimum at 20 °C). The lifespan of cercariae did not exceed 48 h and 50% of them were no more infectious after 7 h. A model was designed (emergence = f(water temperature)) in order to calculate an average monthly cercarial emergence rate according to water temperature that was daily recorded for 5 years (1998-2002). Concomitantly, non-infected cockles were transplanted each of these years in order to assess the infection rate by H. quissetensis. Infection occurred strictly for the same water temperatures (and dates) as those expected for cercariae emergence. Within each year, there was often (but not always) a good correlation between the predicted number of emerging cercariae and the observed number of cercariae transformed into metacercariae in cockles. However, the among-years variability of cockle infection (× 4.4 range) was not explained by the predicted annual number of emerging cercariae. This study highlights the importance of water temperature and light in stimulating cercariae emergence which is closely related to the

  13. Toxicity of cadmium to Schistosoma mansoni cercariae: effects on vitality and developmental ability in white mice

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    Holliman, R.B. (Virginia Polytechnic Inst. and State Univ., Blacksburg); Esham, L.P.

    1977-09-29

    Time-until-death studies were run on cercariae of Schistosoma mansoni in 8 concentrations of cadmium (from cadmium sulfate) ranging from 100 ppM to 0.0001 ppM. All concentrations used were found to be toxic, and at 10 ppM all cercariae were dead within 4 hours, which coincides with their period of maximum infectability following emergence from the snail host. At 2 ppM, all cercariae died within 8 hours, and at 1 ppM all died within 16 hours. In addition, groups of cercariae were exposed to cadmium concentrations of 10, 1, and 0.1 ppM for periods of 30, 20, and 10 minutes. Thereafter, cercariae from these groups were allowed to penetrate the tails of white mice or were injected subcutaneously into mice. After 8 weeks, these mice were autopsied and the adult worms collected by perfusion. Maturation of cercariae from both methods of invasion was seriously impaired. Statistical analysis using a 3 x 4 x 2 factoral design for analysis of variance showed both time of exposure and concentration of cadmium ion to be significant factors in determining number of worms developing at p = 0.01. A significant interaction between time of exposure and concentration was found to exist. The two methods of infection did not have a significant effect on the number of worms recovered. Therefore, it appears that those toxicant-exposed cercariae capable of maturing do not need assistance in transversing the skin barrier but can penetrate and migrate to reach the mesenteric venules for maturation.

  14. Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents.

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    Sunita, Kumari; Habib, Maria; Kumar, P; Singh, Vinay Kumar; Husain, Syed Akhtar; Singh, D K

    2016-02-01

    Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively. PMID:26536397

  15. Investigation of the swimming mechanics of Schistosoma cercariae and its role in disease transmission

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    Krishnamurthy, Deepak; Bhargava, Arjun; Katsikis, Georgios; Prakash, Manu

    2015-11-01

    Schistosomiasis is a Neglected Tropical Disease responsible for the deaths of an estimated 200,000 people annually. Human infection occurs when the infectious forms of the worm known as cercariae swim through freshwater, detect humans and penetrate the skin. Cercarial swimming is a bottleneck in disease transmission since cercariae have finite energy reserves, hence motivating studies of their swimming mechanics. Here we build on earlier studies which revealed the existence of two swimming modes: the tail-first and head-first modes. Of these the former was shown to display a novel symmetry breaking mechanism enabling locomotion at low Reynolds numbers. Here we propose simple models for the two swimming modes based on a three-link swimmer geometry. Using local slender-body-theory, we calculate the swimming gait for these model swimmers and compare with experiments, both on live cercariae and on scaled-up robotic swimmers. We use data from these experiments and the models to calculate the energy expended while swimming in the two modes. This along with long-time tracking of swimming cercariae in a lab setting allows estimation of the decrease in activity of the swimmer as a function of time which is an important factor in cercarial infectivity. Finally, we consider, through experiments and theoretical models, the effects of gravity since cercariae are negatively buoyant and sink in the water column while not swimming. This sinking affects cercarial spatial distribution which is important from a disease perspective.

  16. Inhibition of acetylcholinesterase and cytochrome oxidase activity in Fasciola gigantica cercaria by phytoconstituents.

    Science.gov (United States)

    Sunita, Kumari; Habib, Maria; Kumar, P; Singh, Vinay Kumar; Husain, Syed Akhtar; Singh, D K

    2016-02-01

    Fasciolosis is an important cattle and human disease caused by Fasciola hepatica and Fasciola gigantica. One of the possible methods to control this problem is to interrupt the life cycle of Fasciola by killing its larva (redia and cercaria) in host snail. Molecular identification of cercaria larva of F. gigantica was done by comparing the nucleotide sequencing with adult F. gigantica. It was noted that nucleotide sequencing of cercaria larva and adult F. gigantica were 99% same. Every month during the year 2011-2012, in vivo treatment with 60% of 4 h LC50 of phyto cercaricides citral, ferulic acid, umbelliferone, azadirachtin and allicin caused significant inhibition of acetylcholinesterase (AChE) and cytochrome oxidase activity in the treated cercaria larva of F. gigantica. Whereas, activity of both enzymes were not significantly altered in the nervous tissues of vector snail Lymnaea acuminata exposed to same treatments. Maximum reduction in AChE (1.35% of control in month of June) and cytochrome oxidase (3.71% of control in the month of July) activity were noted in the cercaria exposed to 60% of 4 h LC50 of azadirachtin and allicin, respectively.

  17. Three new species of cercariae from Melanopsis praemorsa (L. 1758, Buccinum) snails in Al-Bathan fresh water body, Palestine

    Institute of Scientific and Technical Information of China (English)

    Sami Bdir; Ghaleb Adwan

    2012-01-01

    Objective: To investigate other new species of cercariae encountered in Melanopsis praemorsa (M. praemorsa) snails collected from Palestine. Methods: A total of 1 100 M. praemorsa were collected from Al-Bathan water body, Palestine, from November, 2010 to November, 2011. Cercariae in M. praemorsa were obtained by emerging and crushing methods. Results: Other three new different species of cercariae have been identified from this snail. These species were Xiphidiocercaria (Cercaria melanopsi palestinia IV), Microcercous (Cercaria melanopsi palestinia V) and Longifurcate cercaria (Cercaria melanopsi palestinia VI). The infection rate ofM. praemorsa with these three different cercariae was (42.2%). Coinfection with Xiphidiocercariae and Longifurcate cercariae or Xiphidiocercariae and Microcercous cercariae has been noted and coinfection rate was 1.23% among the infected snails. The highest cercarial infection rate was in June (64.3%). No infected snails were found in September. It was also noted that infected snails attained a larger size than uninfected ones and all infected snails had a size between 17-22 mm (average 20 mm). Conclusions: Our studies imply that there are potentially more new species of trematodes in this area than were found until now. Due to the presence of infected M. praemorsa and may be species of other snails, water resources could be contaminated by the emerging new cercariae, consequently attack the local people directly via the skin or are transferred to them by metacercariae ingestion. More surveys are needed to identify the real prevalence of the trematodes both in human and animal hosts, and also to determine the range of snail hosts of the parasite in enzootic areas of the disease, as well as the life cycle and biology of trematodes and its effects on man should be elucidated.

  18. Immunization of pigs against infection with Schistosoma japonicum using ultraviolet-attenuated cercariae

    International Nuclear Information System (INIS)

    Since pigs are important in the zoonotic transmission of schistosomiasis japonica in China, a veterinary vaccine might contribute to the control of the disease in humans. Pigs were immunized with three doses each of 10 000 cercariae of Schistosoma japonicum attenuated with ultraviolet light (400 μWatt.min/cm2). The experiment was performed with portable irradiation equipment in a rural area of the Hubei Province (P.R. China). A challenge infection of 1000 untreated cercariae was given 2.5 or 6 months after the last immunization, and age-matched naive pigs were challenged as a control. Immunized pigs developed about 90% resistance against the challenge. The liver egg load of these animals was reduced by over 90%. Less than 0.01% of the immunizing cercariae developed to adult parasites and the vaccination had no apparent adverse influence on the pig's health. (Author)

  19. Malformations and mortality in the Asian Common Toad induced by exposure to pleurolophocercous cercariae (Trematoda: Cryptogonimidae).

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    Jayawardena, Uthpala A; Tkach, Vasyl V; Navaratne, Ayanthi N; Amerasinghe, Priyanie H; Rajakaruna, Rupika S

    2013-06-01

    Malformations and increased mortality due to infection by the digenetic trematode, Riberioa ondatrae have been reported for many species of amphibians. Severe malformations have also been reported in the Common Hourglass Tree Frog, Polypedates cruciger induced by pleurolophocercous cercariae in Sri Lanka in addition to the changes in the behaviour, development and survival of the host. We exposed pre-limb bud stage tadpoles (Gosner stages 25-26) of the Asian Common Toad, Duttaphrynus melanostictus to the same pleurolophocercous type cercariae under laboratory conditions. Molecular and morphological identification showed that these cercariae belonged Acanthostomum burminis infecting freshwater snakes as definitive hosts. These cercariae induced malformations (27.8%) and reduced survival to metamorphosis (53.8%). The magnitude of the effects increased with the dose of cercariae. Types of malformations were mainly axial, such as scoliosis and kyphosis. Severe limb malformations such as extra or missing limbs as reported for amphibians exposed to R. ondatrae were not observed in the D. melanostictus. Same authors reported a higher percentage of malformations previously when P. cruciger was exposed to the cercariae A. burminis compared to D. melanostictus. However, tadpoles of D. melanostictus, which are smaller compared to those of P. cruciger, experienced higher mortality than P. cruciger tadpoles. Trematode induced malformations and mortality in amphibians are highly variable and depend on multiple factors such as host species differences such as resistance to infection and tolerance, life-history characteristics such as size at metamorphosis and length of the metamorphosis period, and other factors such as size of the amphibian at the time of trematode exposure. PMID:23353759

  20. Immunizing effect of irradiated homogenate of schistosomal cercariae against bilharzial ultrastructural damage in mice intestinal epithelium

    International Nuclear Information System (INIS)

    The present study is a parasitological and electron microscopical investigation on the immunizing effect of normal and gamma irradiated homogenate cercariae of Schistosoma Mansoni against Bilharzial complications in the fine structure of the intestinal epithelium of mice. A group of mice was exposed, through tail immersion to live wild cercariae and was used as a control, (1st group), whereas the two other groups were injected with either unirradiated (400 Gy) (2nd group) or irradiated homogenate (3rd group) of schistosoma Mansoni cercariae and challenged with wild cercariae. All group were sacrificed 6 weeks post infection and the intestinal tissues were examined by the electron microscope. The Ist group showed considerable alterations in the different organelles of the cells. Abnormalities in epithelial cells appeared in goblet cells being deformed, shorter and adhering to microvilli, with degenerative cytoplasm and nuclei. In 2nd group, the intestinal epithelial cells were injured showing dark goblet cells. swollen mitochondria whereas microvilli and nuclei appeared normal. The 3rd group displayed epithelial cells with a relatively normal ultrastructure

  1. Effect of gamma-radiation on cercariae of Schistosoma incognitum and S. spindale

    International Nuclear Information System (INIS)

    In the present study an attempt has been made to study the effect of gamma radiation on cercariae of Schistosoma incognitum and S. spindale in mice at different dose levels of radiation, so as to note differences in their developmental patterns, compared with non-irradiated controls. (author). 10 refs

  2. Induction of species-specific immunity against Schistosoma japonicum by exposure of rats to ultra-violet attenuated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Moloney, N.A.; Webbe, G.; Hinchcliffe, P.

    1987-02-01

    Single percutaneous immunizations of Fischer rats with 1000 ultra-violet attenuated Schistosoma japonicum cercariae induced 52-88% resistance to challenge 4 weeks later. Increasing this to 3 immunizations induced 90% resistance to challenge, and this level of protection remained undiminished for up to 40 weeks after vaccination. Rats vaccinated with gamma-irradiated S. mansoni cercariae were resistant to challenge with S. mansoni but not S. japonicum. Similarly rats vaccinated with u.v.-attenuated S. japonicum cercariae were not resistant to heterologous challenge. Thus irradiated vaccines are species-specific in both permissive and non-permissive hosts.

  3. The neuro-muscular system in continuously swimming cercariae from Belarus. I Xiphidiocercariae.

    Science.gov (United States)

    Tolstenkov, Oleg O; Akimova, Ludmila N; Terenina, Nadezhda B; Gustafsson, Margaretha K S

    2012-11-01

    The neuromuscular system (NMS) in cercariae of Neoastiotrema trituri, Plagiorchis elegans, Omphalometra flexuosa, Skrjabinoeces similis and Prosthogonimus ovatus was studied with immunocytochemical methods and confocal scanning laser microscopy. The patterns of F-actin in the musculature, 5-HT immunoreactive (IR), FMRFamide-IR neuronal elements and α-tubulin-IR sensory receptors were investigated, and they were found to be rather similar in all the cercariae studied. Four species have seven paired 5-HT-IR neurons in the body, and P. elegans has eight. N. trituri has three 5-HT-IR neurons in each brain ganglion, while the other species have four. A high degree of conformity in the structure of the NMS was observed, probably reflecting the close phylogenetic relationship and the similar strategy of host finding.

  4. Reinfection immunity in schistosomiasis. With special reference to immunity induced by radiation attenuated Cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Haruo

    1987-07-01

    Schistosomiasis is one of the most important parasitic diseases in the world, especially in endemic areas of developing countries. This situation has prompted parasitologist to attempt intensive researches on immune mechanisms, especially those of reinfection immunity associated with eliminating challenge infection. The current knowledge of reinfection immunity against Schistosoma spp. infection was therefore reviewed briefly and discussed with special reference to our data on protective immune responses induced by radiation-attenuated cercarial infection. A recently developed technique of compressed organ autoradiography (COA) has contributed to assessing parasite attrition in immune animals following challenge infection. Our study using COA has demonstrated that major attrition of schistosomula from challenge infection occurs in the skin of CBA/Ca mice vaccinated with 20 Krad gamma radiation-attenuated cercariae of S. mansoni, while in both lungs and liver of similarly vaccinated guinea pig model. Furthermore, gamma-irradiation to cercariae affected their migration potential and surface-antigen profiles. The immunizing stimuli of gamma radiation-attenuated cercariae profoundly affected the expression of responsiveness in vaccinated animals. The change in antigenic profiles and migration potential of those vaccinating population was discussed in relation to the kinetics of reinfection immunity induced in vaccinated amimal models. These works might provide a base line data to develop a practical vaccine for schistosomiasis using defined antigens. It must be emphasized that these vaccines could serve as a practical prophylactic measure for schistosomiasis in the endemic areas, even if the vaccines fail to induce sterilizing immunity. (author). 141 refs.

  5. Adhesion of Cercaria (Larva of Helminth Parasites to Host by Lectins- Carbohydrates Bonds as a Model for Evaluation of Schistosoma Entrance Mechanisms in Cercarial Dermatitis

    Directory of Open Access Journals (Sweden)

    A Farahnak

    2008-07-01

    Full Text Available Background: Cercariae (larva of helminth parasites are covered by a thick glycocalyx coat, which serves as an osmotic protection during their free existence, and contain carbohydrates conjugated as glycoproteins, glycolipids and mucopolysaccharides. Although, limited studies have been made on life cycle of cercariae from fresh water snails, however, carbohydrate studies on cercariae have not been done in Iran so far. This study was made to determine the cercariae specifications from Lymnaea gedrosiana and evaluation of surface carbohydrates as receptors for host lectins in a host-parasite relationship system as a model in human schistosomiasis including cercarial dermatitis in Khuzestan Province. Methods: For this purpose, snails were collected from Dezful region in Khuzestan Province and cercariae were obtained by shedding method and identified by valuable keys. Experimental infection was established in the Culex pipiens (Culicidae mosquitoes larvae for further identification and mode of adhesion. To detect the mode of adhesion, surface carbohydrates of cercariae were detected by lentil (Lens culinaris lectins. Results: Examined snails were infected with xiphidiocerceria of trematodes and metacercariae were obtained from Culex pipiens. Also, Mannose monosaccharides- CH2OH (CHOH 4CHO - were detected particularly on the glands of cercariae. Conclusion: Adhesion of cercariae to their host by lectins-carbohydrates bonds is the first stage of host-parasite relationship. This phenomenon could be happened for animal schistosome's cercaria in cercarial dermatitis.

  6. The neuromuscular system in continuously swimming cercariae from Belarus. II Echinostomata, Gymnocephala and Amphistomata.

    Science.gov (United States)

    Tolstenkov, Oleg O; Akimova, Ludmila N; Terenina, Nadezhda B; Gustafsson, Margaretha K S

    2012-12-01

    The neuromuscular system in cercariae of Moliniella anceps, Echinostoma revolutum, Cathaemasia hians, Psilochasmus oxyurus, Sphaeridiotrema globulus, Paramphistomum cervi and Diplodiscus subclavatus was studied with immunocytochemical methods and confocal scanning laser microscopy. The patterns of F-actin in the musculature, 5-HT immunoreactive (IR), FMRFamide-IR neuronal elements and α-tubulin-IR sensory receptors were investigated. The general patterns of musculature, 5-HT- and FMRFamide-IR neuronal elements in the 12 species studied here and in paper I are similar to those observed in other cercariae and reflect the morphology of the groups. The musculature of the tail shows variations which are related to the different strategies of host finding. In the Echinostomatoidea and Paramphistomoidea, the striated musculature of the tail is well developed compared to that in the Xiphidiocercariae. Specialized muscle fibres were found in S. globulus, which are able to change the shape of the tail. Nine of the species studied have seven paired 5-HT-IR neurons in the body, and two species have eight. No correlation between the body size and the number of 5-HT-IR neurons was observed. However, the size of the neurons followed the body size. The number of 5-HT-IR neurons in the brain ganglia increased from the primitive to the advanced forms. The number of FMRFamide-IR transverse commissures in the body correlates with the size of the cercariae. Regardless of the differences in the second intermediate host, the distribution of α-tubulin-IR sensory receptors shows a high degree of conformity in all species except in P. cervi, which encysts on plants.

  7. Pulmonary leukocytic responses are linked to the acquired immunity of mice vaccinated with irradiated cercariae of Schistosoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, R.; Coulson, P.S.; Wilson, R.A.

    1988-05-15

    Pulmonary cellular responses in C57BL/6 mice exposed to Schistosoma mansoni have been investigated by sampling cells from the respiratory airways with bronchoalveolar lavage. Mice exposed to cercariae attenuated with 20 krad gamma-radiation developed stronger and more persistent pulmonary leukocytic responses than animals exposed to equal numbers of normal parasites. Although vaccination with irradiated cercariae also stimulated T cell responses of greater magnitude and duration than normal infection, the lymphocytic infiltrate elicited by each regimen did not differ substantially in its composition, 5 wk after exposure. Studies with cercariae attenuated by different treatments established that a link exists between the recruitment of leukocytes to the lungs of vaccinated mice and resistance to reinfection. There was a strong association between pulmonary leukocytic responses and the elimination of challenge infections by vaccinated mice. Animals exposed to irradiated cercariae of S. mansoni were resistant to homologous challenge infection but were not protected against Schistosoma margrebowiei. Homologous challenge of vaccinated mice stimulated anamnestic leukocytic and T lymphocytic responses in the lungs, 2 wk postinfection, but exposure of immunized animals to the heterologous species failed to trigger an expansion in these populations of cells. Our studies indicate that pulmonary leukocytes and T lymphocytes are intimately involved in the mechanism of vaccine-induced resistance to S. mansoni. It remains unclear whether these populations of cells initiate protective inflammatory reactions against challenge parasites in the lungs, or accumulate in response to the activation of the protective mechanism by other means.

  8. Schistosoma mansoni polypeptides immunogenic in mice vaccinated with radiation-attenuated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, J.P.; Strand, M.

    1987-10-01

    We compared the humoral immune response of mice protected against Schistosoma mansoni by vaccination with radiation-attenuated cercariae to that of patently infected mice, and we identified antigens that elicit a greater, or unique, immune response in the vaccinated mice. These comparisons were based upon radioimmunoprecipitations and immunodepletion of (/sup 35/S)methionine-labeled schistosomular and adult worm polypeptides, followed by one- and two-dimensional polyacrylamide gel analyses. The humoral responses of patently infected mice and of mice vaccinated once were remarkably similar and were directed against schistosome glycoproteins ranging in molecular size from greater than 300 to less than 10 kDa. Exposing mice to a second vaccination resulted in a marked change in the immune response, to one predominantly directed toward high molecular size glycoproteins. Sequential immunodepletion techniques identified five schistosomular and seven adult worm antigens that showed a greater or unique immunogenicity in vaccinated mice as compared with patently infected mice. These adult worm antigens were purified by preparative sequential immunoaffinity chromatography and used to prepare a polyclonal antiserum, anti-irradiated vaccine. This antiserum bound to the surface of live newly transformed and lung-stage schistosomula, as assessed by immunofluorescence assays, and was reactive with a number of /sup 125/I-labeled schistosomular surface polypeptides, including a doublet of 150 kDa that was also recognized by sera of vaccinated mice but not by sera of patently infected mice.

  9. [A comparative study of excretory and sensory apparatus of two cercariae of Diplodiscus parasites of European and African Amphibians (Trematoda, Diploidiscidae) (author's transl)].

    Science.gov (United States)

    Bayssade-Dufour, C; Albaret, J L; Grabda-Kazubska, B; Kulo, S D

    1978-01-01

    The comparative study of the excretory system provides new data on the number of flame cells of two cercariae of Diplodiscus from Poland and Togo but does not allow to distinguish them. On the other hand, the comparison of the superficial sensory apparatus shows significant differences. The cercariae from Togo differ from these of Poland by a much lower number of all the cephalic papillae and papillae of cycle Cv, a higher number of acetabular papillae, and the presence of 9 to 12 pairs of dorsal papillae in the median part of the tail. Therefore the African Diplodicus is not D. subclavatus. We identify it as D. fischthalicus. PMID:754617

  10. Differences in Brazilian strains of Schistosoma mansoni evaluated by means of morphometric analysis of cercariae of both sexes

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    José Roberto Machado-Silva

    2000-12-01

    Full Text Available Morphometrics of Brazilian strains (BH, SJ and CMO of Schistosoma mansoni cercariae were obtained with a computerized image analyzer (IMAGE PRO PLUS, MEDIA CYBERNETICS, considering the following characters: body area, tail, furcae, oral and ventral suckers and distance between them. For statistical analysis, the variance test (one-way Anova was applied and significant differences of p< 0.05 were considered. All morphometric values in the BH strain were significantly higher (p< 0.05 than in the others. Lower values were obtained in females of SJ strain for all characters, excepting the body area. Only this character showed to be significantly different in males and females of the three strains. Specimens of both sexes in the BH and SJ strains showed significant differences regarding all characters. It was observed that this morphometric analysis permits the characterization of strains and also the sex identification in S. mansoni cercariae. Due to its feasibility, this method can be applied as a tool in laboratories devoid of more complex equipment.

  11. Ultrastructure and chaetotaxy of sensory eeceptors in the cercaria of a species of Allopodocotyle Pritchard, 1966 (Digenea: Opecoelidae

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    T Bogéa

    2001-02-01

    Full Text Available Previous investigations of sensory systems in opecoelid cercariae have focused on chaetotaxy and ultrastructure of sensory receptors. They revealed chaetotaxic patterns within family, genus, and species as well as different receptors. Chaetotaxic and ultrastructural observations have rarely been combined. We investigated the ultrastructure of cercarial sensory receptors in conjunction with chaetotaxy and neuromorphology in a species of Allopodocotyle. Cercariae were treated with acetylthiocholine iodide and silver nitrate, and some were processed for light, scanning (SEM, and transmission (TEM electron microscopy. Five nerve regions were distinguished. Chaetotaxy was consistent with that of other opecoelids. Five types of receptors were distinguished with SEM. Types differed in number of cilium-like structures (one or more, length of cilium-like structure (short, moderately long, or long, presence or absence of a tegumentary collar, and length of tegumentary collar (low, moderately low, or very high. Internal ultrastructure of some types revealed unsheathed cilium-like structures, basal body, and thickened nerve collars. Possible subtegumentary and sheathed receptors are introduced. Some receptor types were site-specific. For example, receptors with multiple cilium-like structures were concentrated on cephalic region whereas receptors with short cilium-like structure were widespread throughout most regions. Ultrastructure and site-specificity observations suggest that most receptors are mechanoreceptors.

  12. Schistosoma mansoni: quantitative aspects of the fertility and survival of worms obtained from irradiated cercariae (3 Krad), in mice

    International Nuclear Information System (INIS)

    The effect of gamma irradiation on the fertility of female mice, as well as the survival of worms in their portal system, have been observed in four groups of outbred albino mice (Mus musculus), experimentally infected with ca 450 cercariae of Schistosoma mansoni (LE and SJ strains), by transcutaneous route. The cercariae used were a) non-irradiated (control groups), and b) irradiated with 3 Krad of gamma irradiation (Co-60). From the 33rd day on, some stability in the population of surviving worm could be observed. This population remained constant till the end of the observation period (90th day), notedly in relation to the LE strain . Thus, it was concluded that gamma irradiation (at the dose of 3 Krad) is able to hinder the worm egg production in 98.1% of the infected mice. Further, it was observed that the few detected eggs were dead. Females were found to be more resistant to irradiation. The irradiation effect on the mortality of male worms was statistically significant scarcely from the 61st day on. The long period of permanence of the sterile adult irradiated worms in the portal system of mice and their probable involvement in the development of immuno-protection (the so-called concomitant immunity, without the immuno-pathological involvements for the host) are here discussed. (author)

  13. Gene Transcription Profile in Mice Vaccinated with Ultraviolet-attenuated Cercariae of Schistosoma japonicum Reveals Molecules Contributing to Elevated IFN-γLevels

    Institute of Scientific and Technical Information of China (English)

    Xiang ZHU; Feng LIU; Chuan SU; Guan-Ling WU; Zhao-Song ZHANG; Min-Jun JI; Hai-Wei WU; Yong WANG; Xiao-Ping CAI; Lei ZHANG; Shu-Ying HU; Lin-Lin FU

    2005-01-01

    Vaccination with ultraviolet-attenuated cercariae of Schistosoma japonicum induced protective immunity against challenge infection in experimental animal models. Our preliminary study on the transcription levels of IFN-γ and IL-4 in splenic CD4+ T cells revealed that attenuated cercariae elicited predominantly a Thl response in mice at the early stage, whereas normal cercariae stimulated primarily Th2dependent responses. Further analysis on the gene profile of the skin-draining lymph nodes demonstrated that the levels of IFN-γ were significantly higher in vaccinated mice than those in infected mice at day 4, 7 and 14 post-vaccination or post-infection. However, for IL-12 and IL-4, the potent inducers of Th l and Th2 responses, respectively, as well as IL-10, there were no differences over the course of the experiment between the infected and vaccinated mice. To explore the underlying factors that may potentially contribute to elevated IFN-γ in vaccinated mice, the mRNA profiles of the skin-draining lymph nodes at day 4 postexposure were compared using oligonucleotide microarrays. Within the 847 probe sets with increased signal values, we focused on chemokines, cytokines and relevant receptors, which were validated by semi-quantitative RT-PCR. A comprehensive understanding of the immune mechanisms of attenuated cercariae-induced protection may contribute to developing efficient vaccination strategies against S. japonicum, especially during the early stage of infection.

  14. Evaluation of lung recovery assay for schistosomula in mice immunized with X-irradiated cercariae of Schistosoma mansoni

    International Nuclear Information System (INIS)

    The lung recovery assay for schistosomula has recently been used as a rapid method for measuring the state of immunity of a challenged animal. Its merit rests on the fact that the peak day of schistosomular recovery in the lungs of both normal and immune hosts falls on the same day and the degree of immunity can be measured by the percent of schistosomular recovery on this particular day. An evaluation of this method for mice immunized with highly X-irradiated cercariae of Schistosoma mansoni was made. The results indicate that in the immunized mice the peak day for the schistosomular recovery was delayed and the number of schistosomula recovered on the peak day was decreased. (orig./AJ) 891 AJ/orig.- 892 HIS

  15. Formation and Controlled Drug Release Using a Three-Component Supramolecular Hydrogel for Anti-Schistosoma Japonicum Cercariae

    Directory of Open Access Journals (Sweden)

    Yibao Li

    2016-03-01

    Full Text Available A novel three-component supramolecular hydrogel based on riboflavin, melamine and amino acid derivatives were constructed for controlled release of pesticides, Niclosamide derivatives. The formation of hydrogel may be attributed to self-assemble via hydrogen bonding and π–π interaction, which have been researched via scanning electron microscopy (SEM and Fourier transform infrared (FT-IR spectra. The rheological experiments showed that the hydrogel materials and drug-loaded hydrogel all demonstrated good mechanical strength and high stability. Further experimental results indicated that the drug-loaded hydrogels show large drug loadings, long-term release time and relatively higher efficiency to anti-cercariae in the water environment.

  16. The role of antibody affinity and titre in immunity to Schistosoma mansoni following vaccination with highly irradiated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Vignali, D.A.A.; Devey, M.E.; Bickle, Q.D.; Taylor, M.G. (London School of Hygiene and Tropical Medicine (UK))

    1990-02-01

    Sera from rabbits and rats vaccinated with highly irradiated cercariae of Schistosoma mansoni (VRabS, VRatS) were found to be of substantially higher affinity than sera from CBA mice vaccinated four times (4 x CVMS), single sex sera (SSS) or chronic infection sera (CIS). In contrast, immunoprecipitation studies demonstrated that sera from vaccinated LA mice (LVMS) recognized {sup 125}I-labelled schistosomular surface antigens more intensely than sera from vaccinated HA mice (HVMS). However, peritoneal macrophages from HA and LA mice in the presence of HVMS, LVMS or 4 x CVMS, and naive macrophages activated in vitro with interferon-gamma (IFN-{gamma})/lipopolysaccharide (LPS) mediated comparable levels of schistosomula killing in vitro. The experiments described here provide evidence that the titre of antibody rather than its affinity may be a more critical factor in the development of optimal immunity to S. mansoni. (author).

  17. Observações adicionais sobre o sexo do "Schistosoma mansoni" nas infestações por cercarias de um unico molusco Further observations on the sex of "Schistosoma mansoni" in the infestations produced by cercariae from a single snail

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    W. Lobato Paraense

    1949-12-01

    Full Text Available Em um córrego situado nos terrenos do Instituto Oswaldo Cruz, em Man¬guinhos, no qual existe uma população de Australorbis olivaceus, foi verificada a infestação natural dêste planorbídeo pelo Schistosoma mansoni, com o índice de 8.25% baseado na dissecção de 400 moluscos. As cercárias de 24 planorbídeos foram inoculadas em 24 cobaias, cada vertebrado recebendo as cercárias de um único molusco. Uma segunda série de inoculações em 6 cobaias foi feita com as cercárias de 6 planorbídeos sobreviventes, 10 dias apos a primeira série. As infestações resultantes foram tôdas unissexuais (13 vezes por machos, 11 vezes por fêmeas, observando-se entre os sexos a relação de 1 : 1. Em 6 casos infestados por fêmeas, cerca de 15% destas apresentaram no útero ou no ootipo formações ovulares (figs. 1 a 15, desprovidas de estruturas embrionárias, cujo número variou entre 1 e 6. Êstes ovos, quando depositados no fígado, davam origem a ligeiro infiltrado de células epitelióides e não apresentavam organização embrionária. Não foram vistos ovos nos cortes de intestino. Os órgãos sexuais das fêmeas achavam-se aparentemente bem desenvolvidos em grande número de exemplares. Os machos apresentaram testículos de aparência normal, em número variável de 4 a 9. Em 1% dos exemplares examinados foram encontrados testículos supranumerários. Em 2 casos foram encontrados machos secundàriamente hermafroditas (respectivamente 29% e 25%.The dissection of 400 Australorbis olivaceiis from a brook situated in the grounds of the Instituto Oswaldo Cruz (Manguinhos showed that 8.25 per cent of them were naturally infested with Schistosoma mansoni. The cercariae of 24 snails were inoculated into 24 guinea pigs, each of the latter receiving the cercariae from a single snail. A second series of inoculations with the cercariae of 6 surviving snails was made 10 days after the first series. All resulting infestations were unisexual (13 with

  18. Identification of schistosoma mansoni antigens recognised by spleen cells of C57B1/6 mice immunized with ultraviolet-irradiated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Osman, A.; El Ridi, R. (Cairo Univ. (Egypt)); Guirguis, N. (VACSERA, El Agouza Cairo (Egypt). Biomedical Research Dept.); Dean, D.A. (U.S. Naval Medical Research Unit No. 3, Cairo (Egypt))

    1994-11-01

    Spleen cells of C57B1/6 mice immunized twice with Schistosoma mansoni cercariae attenuated by ultraviolet irradiation proliferated and produced interleukin-(I1)-2 and/or I1-4 in response to both soluble schistosomular and adult worm antigens of 72-68, 60-62, 50, 45, 29.5 and 28 kDa. All of these bands, except the 45 kDa, were also recognized by serum antibodies in Western blotting. (author).

  19. Comparative susceptibility of Channel Catfish, Blue Catfish, and their hybrid cross to experimental challenge with Bolbophorus damnificus (Digenea: Bolbophoridae) cercariae.

    Science.gov (United States)

    Griffin, Matt J; Reichley, Stephen R; Khoo, Lester H; Ware, Cynthia; Greenway, Terrence E; Mischke, Charles C; Wise, David J

    2014-06-01

    The digenetic trematode Bolbophorus damnificus has been implicated in significant losses in catfish aquaculture since the late 1990s. The complex life cycle sequentially involves the American white pelican Pelecanus erythrorhynchos, the marsh rams horn snail Planorbella trivolvis, and Channel Catfish Ictalurus punctatus. Research supports anecdotal reports from the industry, suggesting that the hybrid of Channel Catfish×Blue Catfish I. furcatus is less susceptible to disease agents that have been historically prohibitive to Channel Catfish production, namely the gram-negative bacteria Edwardsiella ictaluri and Flavobacterium columnare, as well as the myxozoan parasite Henneguya ictaluri. This current research compared the susceptibility of Channel Catfish, Blue Catfish, and their hybrid cross to an experimental challenge by B. damnificus. Fish were exposed to 0, 100, 200, and 400 B. damnificus cercariae per fish, and the numbers of metacercariae per fish were determined 14 d postchallenge. Metacercariae were recovered from all challenged fish. There were no significant differences among fish groups challenged with the same dose, suggesting Channel and Blue Catfish and their hybrid are comparably susceptible to B. damnificus infection. As such, it is recommended that producers raising hybrid catfish remain diligent in controlling populations of the snail intermediate host to prevent production losses attributed to B. damnificus, especially when loafing pelicans have been observed at the aquaculture operation. PMID:24895863

  20. Schistosoma mansoni: aspectos quantitativos da evolução de cercarias irradiadas a nível da pele, pulmões e sistema porta, em camundongos Schistosoma mansoni: quantitative aspects of the evolution of gamma-irradiated cercariae at the skin, lungs, and portal system, in mice

    Directory of Open Access Journals (Sweden)

    Gileno de Sá Cardoso

    1989-10-01

    Full Text Available Foi estudada a migração do Schistosoma mansoni (cepas LE e SJ em oito grupos de camundongos albinos (Mus musculus não isogênicos, infectados transcutaneamente com cerca de 450 cercarias não irradiadas (grupos controles e irradiadas com 3 Krad, 20 Krad e 40 Krad de radiação gama proveniente de cobalto-60, Na pele, observou-se uma diminuição progressiva das taxas de recuperação em função do tempo e, nos pulmões e sistema porta, verificou-se uma relação inversa significativa entre as taxas de recuperação total e as doses de irradiação. A dose de 20 Krad praticamente impede a migração dos parasites, de ambas as cepas, dos pulmões até o sistema porta, enquanto a de 40 Krad praticamente impede a migração dos mesmos da pele para os pulmões.The migration of Schistosoma mansoni (LE and SJ strains has been studied in eight groups of outbred Swiss albino mice (Mus musculus, which were previously infected with ca 450 cercariae, transcutaneously. The infection of mice was performed with non irradiated cercariae (control groups, or with gamma-irradiated cercariae, at the schedule of 3, 20 and 40 Krad. Regarding the skin, a progressive decrease was detected for the recovery rates, related to the time of infection. As far as the lungs and portal system are concerned, a significant inverse correlation was observed between the total recovery rate and the irradiation dosages. The dose of 20 Krad practically hinders the migration of the parasites (in both strains from the lungs to the portal system, whereas the dose of 40 Krad prevents the migration of most of the parasites from the skin to the lungs.

  1. Analysis and comparison of immune reactivity in guinea-pigs immunized with equivalent numbers of normal or radiation-attenuated cercariae of Schistosoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, M.V.; McLaren, D.J.

    1987-08-01

    Guinea-pigs immunized with equivalent numbers of normal or radiation-attenuated cercariae of Schistosoma mansoni develop close to complete resistance to reinfection at weeks 12 and 4.5 respectively. We here analyse and compare the immune responses induced by the two populations of cercariae. Both radiation-attenuated and normal parasites of S. mansoni elicited an extensive germinal centre response in guinea-pigs by week 4.5 post-immunization. The anti-parasite antibody titre and cytotoxic activity of serum from 4.5-week-vaccinated, or 4.5-week-infected guinea-pigs were approximately equal, but sera from 12-week-infected individuals had high titres of anti-parasite antibody, which promoted significant larvicidal activity in vitro. In all cases, larvicidal activity was mediated by the IgG/sub 2/ fraction of the immune serum. Lymphocyte transformation tests conducted on splenic lymphocytes from 4.5-week vaccinated guinea-pigs revealed maximal stimulation against cercarial, 2-week and 3-week worm antigens, whereas spleen cells from 4.5-week-infected guinea-pigs were maximally stimulated by cercarial and 6-week worm antigens. The splenic lymphocyte responses of 12-week infected animals were dramatic against antigens prepared from all life-stages of the parasite.

  2. In vivo effects of monoclonal anti-L3T4 antibody on immune responsiveness of mice infected with Schistosoma mansoni. Reduction of irradiated cercariae-induced resistance

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, E.A.; Colley, D.G.

    1988-04-15

    Mice can be partially protected against challenge infections of Schistosoma mansoni cercariae by either single or multiple exposure to irradiated cercariae (x-cerc). The participation of L3T4+ lymphocytes on this resistance phenomenon was evaluated by selectively depleting this cell population through in vivo administration of mAb anti-L3T4 at three different times in relationship to the challenge infections. Treatment with anti-L3T4 before challenge such that depletion was effective during the time of cercarial skin penetration and dermal/s.c. residence significantly reduced the level of resistance induced by x-cerc sensitization. When treatment was delayed until after challenge, depletion of L3T4+ cells coincided with either the lung or post-lung/liver phases of schistosomular migration, and normal levels of x-cerc-induced resistance were induced. In contrast to once-immunized mice, mice hyperimmunized by five exposures to x-cerc and then depleted of L3T4+ cells at the time of challenge still expressed resistance to the challenge. These data suggest that when mice are sensitized only once with x-cerc the challenge infection provides a necessary immunologic boost which requires L3T4+ cells for effective expression of resistance. The requirement for this anamnestic effect by the challenge infection can be circumvented by hyperimmunization. Evaluation of the immune response of one-time sensitized or hyperimmunized mice demonstrated that cellular Ag-specific proliferative responses and mitogen-induced lymphokine production were abrogated after any of the various in vivo regimens of anti-L3T4 antibody. In contrast, immunoblot analysis of humoral responsiveness revealed a correlation between the expression of resistance and the ability of sera from immunized and anti-L3T4 treated mice to recognize a 75-kDa parasite antigenic component.

  3. Schistosoma mansoni: analysis of the humoral and cellular basis of resistance in guinea-pigs vaccinated with radiation-attenuated cercariae

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, D.J.; Delgado, V.S.; Gordon, J.R.; Rogers, M.V. (National Inst. for Medical Research, London (UK))

    1990-02-01

    This study addresses the humoral and cellular basis of specific acquired immunity in the guinea-pig irradiated vaccine model of schistosomiasis mansoni. Rodents vaccinated with 500 gamma-irradiated cercariae and then splenectomized 4. 5 weeks later showed a 33% reduction in resistance to challenge as compared to vaccinated animals or vaccinated/sham splenectomized controls. Serum harvested from once vaccinated individuals conferred modest levels of resistance upon naive recipients in some experiments, but transfer was not achieved consistently. Serum from vaccinated and thrice boosted rodents (Vbbb) routinely transferred about 45% immunity, however, provided it was given in 4 ml aliquots on day 9 post-challenge; Vbbb serum thus transferred 50% of donor immunity. Interestingly, multiple doses of this protective serum given on and either side of day 9 did not enhance the protection achieved with a single 4 ml aliquot. Neither peripheral lymph node cells nor splenocytes from the polyvaccinated serum donors were able to transfer resistance to recipient guinea-pigs and they failed to augment the protection achieved with Vbbb serum. Foot-pad testing revealed no correlation between delayed hypersensitivity responses and immunity to challenge in vaccinated guinea-pigs. Polyvaccine guinea-pig serum failed to protect mice and guinea-pigs could not be protected with polyvaccine rat serum. (author).

  4. Immunity to Schistosoma mansoni in guinea-pigs vaccinated with radiation-attenuated cercariae. T-cell activation of macrophages for larval killing

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J.R.; McLaren, D.J.

    1988-02-01

    This study addresses macrophage activation in guinea-pigs vaccinated with radiation-attenuated cercariae of Schistosom mansoni. Peritoneal exudate macrophages elicited in vaccinated animals by mineral oil injection were activated to kill larval schistosomes in vitro. Killing efficiency is dependent upon the cell:target ratio employed and is enhanced by, but is not strictly dependent on, the presence of specific antibodies. Macrophages co-cultured with parasites release superoxide radicals and hydrogen peroxide, but the use of inhibitors has shown that neither of these reactive oxygen intermediates are the causal agents of cellular cytotoxicity in this system. Oil-elicited macrophages from naive guinea-pigs do not show comparable activation; they can, however, be activated in vitro by incubation with culture supernatant fluids from schistosome antigen-stimulated spleen, or lymph node cells harvested from vaccinated guinea-pigs. Naive macrophages activated in this way kill schistosomula in vitro and release the activation markers IL-l and superoxide anion. The macrophage-activating factor (MAF) present in spleen cell culture supernatant fluids has a MW of 35,000-55,000, but does not have the chemical characteristics of gamma-interferon.

  5. Humoral and cellular immune responses induced in mice by purified iridoid mixture that inhibits penetration of Schistosoma mansoni cercariae upon topical treatment of mice tails.

    Science.gov (United States)

    Bahgat, Mahmoud; Shalaby, Nagwa M M; Ruppel, Andreas; Maghraby, Amany S

    2005-08-01

    When tested for possible blocking effect on the cercarial, serine proteinase, elastase (CE) activity, an iridoid mixture extracted from leaves of Citharexylum quadrangular abolished 31% of the enzyme activity at final concentration 15 microg. When formulated in jojoba oil and applied to mice tails followed by infection with Schistosoma mansoni cercariae, the iridoid mixture blocked cercarial penetration and caused significant reducetion (94%; P < 0.05) in worm burden in treated mice in comparison to controls. Also, immunomodulatory effects of iridoid mixture, iridoid-treated S. mansoni worm homogenate on mice were studied by measuring IgG and IgM levels against E. coli lysates (ECL), solube S. mansoni worm antigenic preparation (SWAP) and cancer bladder homogenates (CBH) as antigens by ELISA. Cellular immune responses were studied by calculating mean percent of CD4+, CD8(+)-T, B-mesenteric lymph node cells (MLNC) and CD4+, CD8(+)-T thymocytes by direct immunofluorescence staining in treated mice as compared to untreated homogenate given mice or untreated mice. Injecting mice with serial dilutions of iridoid mixture resulted in fluctuation, peaks and troughs, in both IgG and IgM responses against the above mentioned antigens. 1st and 2nd immunizations with iridoid mixture treated homogenate resulted in significantly elevated (P < 0.05). IgM and IgG levels against the 3 used antigens in comparison with sera from control mice. Immunized mice with homogenate treated with iridoid mixture showed a significant increase (P < 0.05) in CD4+T thymocytes, a non significant increase in CD8+T thymocytes, a significant increase (P < 0.05) in CD4+T lymphocytes (MLNC) and a non significant increase in CD8+ T- and B-lymphocytes (MLNC) compared with mice immunized with untreated homogenate or non-injected normal mice.

  6. Evidence that radio-sensitive cells are central to skin-phase protective immunity in CBA/Ca mice vaccinated with radiation-attenuated cercariae of Schistosoma mansoni as well as in naive mice protected with vaccine serum

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, V.S.; McLaren, D.J. (National Inst. for Medical Research, London (UK))

    1990-02-01

    Naive CBA/Ca mice and CBA/ca mice vaccinated 4 weeks previously with radiation-attenuated cercariae of Schistosoma mansoni were subjected to 550 rad of whole body (gamma) irradiation and then challenged 3 days later with normal cercariae. The perfusion recovery data showed that this procedure reduced the primary worm burden in naive mice by 22% and the challence worm burden in vaccinated mice by 82%. Irradiation also ablated the peripheral blood leucocytes of both mouse groups by 90-100% at the time of challenge. Histological data revealed that such treatment caused a dramatic change in number, size and leucocyte composition of cutaneous inflammatory skin reactions that characterize challenged vacccinated mice and are known to entrap invading larvae; cutaneous eosinophils were preferentially abolished by this treatment. Polyvaccine mouse serum that conferred protection passively upon naive recipient mice, failed to protect naive/irradiated mice when administered by the same protocol. Distraction of macrophages by treatment of mice with silica did not affect the establishment of a primary worm burden and reduced the protection exhibited by vaccinated mice by only 16%. These data indicade that radio-sensitive cells are important to both innate and specific acquired resistance in this mouse model and that macrophages contribute only marginally to the expression of vaccine immunity. (author).

  7. Production of Shistosoma mansoni cercariae by Biomphalaria glabrata from a focus in Belo Horizonte, Minas Gerais Produção de cercárias de Schistosoma mansoni por Biomphalaria glabrata de foco em Belo Horizonte, Minas Gerais

    Directory of Open Access Journals (Sweden)

    Cecília Pereira de Souza

    1994-12-01

    Full Text Available The snail density, levels of infection and the monthly production of Schistosoma mansoni cercariae by Biomphalaria glabrata were determined in a focus of Barreiro de Baixo (Belo Horizonte, MG, Brazil. During a period of 38 months (1984 to 1987 5,366 snails were collected of which 324 (6.03% were infected with S. mansoni. The total number of cercariae shed was 5,667,312. Each snail shed an average of 17,422 cercariae during the time that it was under study in the laboratory. The greatest longevity of infected snails was 218 days. Natural cure was observed in 42 (12.9% of the infected specimens about 130 days after collection. The average snail density in the focus during the period of study was 16.3 snails per scoop. The shedding of cercariae by snails collected from the field was compared with laboratory bred specimens infected in mass with the LE strain of S. mansoni from Belo Horizonte. The laboratory infected snails shed an average of 6,061 cercariae each, a value 2.8 times less than the field specimens due to a shorter life span. The prevalence of schistosomiasis in the focus was 14.3%.A densidade planorbídica, as taxas de infecção e a produção mensal de cercárias de Schistosoma mansoni por Biomphalaria glabrata, foram determinadas em foco do Barreiro de Baixo (Belo Horizonte MG, Brasil. Durante 38 meses, de 1984 a 1987, foram capturados 5.366 moluscos dentre os quais 324 (6,03% estavam infectados com o S. mansoni. O total de cercárias eliminadas foi de 5.667.312. Cada molusco eliminou em média 17.422 cercárias durante sua permanência no laboratório. A maior longevidade dos moluscos infectados foi de 218 dias. Foi observada a cura natural de 42 (12,9% dos exemplares infectados, após cerca de 130 dias de captura. A densidade planorbídica média, no foco durante esse período foi de 16,3 moluscos por conchada. A eliminação de cercárias pelos moluscos do campo foi comparada com a de exemplares criados no laboratório, infectados

  8. IN VIVO AND IN VITRO ENCYSTMENT OF ECHINOCHASMUS LILIPUTANUS CERCARIAE AND BIOLOGICAL ACTIVITY OF THE METACERCARIAE%藐小棘隙吸虫尾蚴在体内、体外成囊与囊蚴生物学活性实验研究

    Institute of Scientific and Technical Information of China (English)

    肖祥; 汪天平; 王玉萍; 沈光金; 汪奇志

    1999-01-01

    Aim To explore if Echinochasmus liliputanus cercariae can develop into metacercariae both in vivo and in vitro and biological activity of the metacercariae, then to determine the effects of silver nitrate on cercariae encystation in vitro. Methods Cercariae of Echinochasmus liliputanus from Bellamya aeruginosa snails treated with or without silver nitrate were used to infected goldfish, the second intermediate host, or to incubated in many different solutions for 24 h to record the encystation rates. The metacercariae formed both in vivo and in vitro were then used to infected New Zealand rabbits to test their infectivity to its definitive hosts or to excyst in 0.1% sodium deoxycholate excystation medium at 37℃ for 1 h. Results In vivo encystment of cercariae occurred in the gills of goldfish. However, the cercariae were also able to encyst in vitro in Locke's solution, NaCl solution, artificial gastric juice or human gastric juice with encystation rates of 74.28 %, 44.94 %, 8.37 % and 10.79 %. 0.7 × - 1.2 × Locke' s or 0. 7 % - 1.2 % NaCl solution was shown to be appropriate for in vitro encystment to occur within 24 hour, however, full - strength Locke' s solution was shown to be optimal. The one - day - old encysted metacercariae formed in vivo showed 88.53 % excystation when treated in 0.1% sodium deoxycholate excystation medium at 37℃ for 1 h. The metacercariae formed in vitro, however, showed 88.60 % and 84.95 % excystation for normal and abnormal ones respectively. While abnormal cysts at room temperature usually die within 10 days, about 70% normal cyst, both in vivo and in vitro, can still excyst after stored in 0.5 × Locke's at 4℃ for 3 mouths. Cysts formed in vivo and in vitro were equally infective to rabbits. 1 uM silver nitrate had a dramatic effect on the cercariae encysting in vitro.When treated with silver nitrate, the cercariae encystation rates decreased to 16.25 % in Locke's solution and 6.69% in NaCl solution, however, the encystment

  9. Fluorescent quantitative real-time PCR for quantitative detection of Schistosoma japonicum cercariae in water%荧光实时定量PCR定量水体中日本血吸虫尾蚴方法的建立

    Institute of Scientific and Technical Information of China (English)

    王本敬; 王文波; 周霞; 陈艳勤; 张静; 刘晨晨; 梁幼生; 诸葛洪祥

    2011-01-01

    目的 建立快速、高效、特异的定量水体中尾蚴的数量和检测水体中日本血吸虫尾蚴残余基因组DNA的方法,来评估水体受日本血吸虫尾蚴污染的程度.方法 根据日本血吸虫基因组DNA中的3个多拷贝序列Sjrh1.0(序列号:U92488.1)、18S小亚基单位核楷体核酸基因(18SrRNA)序列(序列号:AY157226.1)和逆转录转座子SjR2的G55A序列(G55A)(序列号:AF412221.1),设计常规PCR引物和实时定量PCR引物,选取较好的靶序列建立SYBR GreenI实时定量PCR方法,绘制尾蚴数的对数与Ct值的标准曲线,并对疫水中日本血吸虫尾蚴残余的基因组DNA进行检测.结果 尾蚴数的对数与Ct值的标准曲线有良好的线性关系,相关系数r2为0.918 6,重复性良好.结论 本方法特异性高,灵敏,可定量水体中尾蚴数,对疫水检测有一定的预警作用.%The objective was to establish a rapid, sensitive and specific method to detect the number of cercariea in water and evaluate level of water stained by Schistosoma japonicum cercariea. Convenience PCR primer sequences were designed tar-geting pSjrH1.0(U92488. 1), Sjl8SrRNA( AY157226. 1) and the clone G55A of the highly repetitive retrotransposon SjR2 (AF412221. 1) in S. japonicum genome, and sequence the PCR product. Based on conserved sequence of pSjrHl. 0, Sjl8SrRNA and clone G55A of highly repetitive retrotransposon SjR2 (G55A), design primers and the quantitative real-time PCR essays were established, by which, the amplifying products were 150 to 170 bp. The sequence in S. japonicum genome and the best annealing temperature were selected by comparing their threshold cycle (Ct value). Then the quantitative real-time PCR essays were established under the better annealing temperature, generate standard curve between the logarithms of gradi-ent diluted DNA templates and Ct value. Five DNA samples extracted from 1, 5, 10, 20 and 80 cercariae were used as quanti-tative template to generate standard curve

  10. 辐照致弱血吸虫尾蚴在小动物中诱导的保护力及其影响因素%The protective effects and relevant factors of vaccination with radiation-attenuated schistosome cercariae in small animals

    Institute of Scientific and Technical Information of China (English)

    张素华; 吴海玮

    2008-01-01

    动物免疫/攻击感染实验显示,辐照致弱尾蚴在多种动物模型能诱导出高水平保护力.与辐照致弱曼氏血吸虫(Schistosoma mansoni,S.m)尾蚴诱导产生稳定高保护力相比,辐照致弱日本血吸虫(Schistosoma japonicum,S.j)尾蚴在小动物(特别是小鼠)中诱导产生的保护力常不稳定,可能与尾蚴的生物学特性、免疫程序、实验条件以及所采用的动物品系等因素有关,目前尚缺乏公认的能对其产生稳定高保护力的小鼠品系.该文就辐照致弱尾蚴在小动物尤其是小鼠诱导产生的抗感染保护力,特别是其影响因素作一综述,为构建S.j辐照致弱尾蚴的高保护力动物模型提供参考.%Experiments in animals indicated that attenuated cercariae could induce high level of protection to schistosome infection.Compared with Schistosoma mansoni(S.m),the levels of protection in mouse induced by Schistosoma japonicum(S.j)attenuated cercariae were variable,which may be related with several factors,such as the biological features of cercariae,the immunization procedure,experimental environment,animal strains,etc.There is still no well-established mice model that would show stable protection after S.j attenuated cercanae vaccination.Hence,we reviewed here the protective effects induced by vaccination with radiation-attenuated schistosome cercariae in small animals,especially the relevant influential factors.

  11. 蒿甲醚或吡喹酮早期治疗感染血吸虫尾蚴兔和犬的肝脏显微镜检查%Microscopic observations on livers of rabbits and dogs infected with Schistosoma japonicum cercariae and early treatment with artemether or praziquantel

    Institute of Scientific and Technical Information of China (English)

    肖树华; 杨元清; 张超威; 尤纪青

    1996-01-01

    To study the histopathological change of the liver of the hosts treated with artemether (Art) or praziquantel (Pra) in early stage after infection with Schistosoma japonicum cercariae. METHODS:Dogs infected once with schistosome cercariae were by the repeated dosing once every 1 or 2 wk for 2 -4 times. In rabbits, infected with 48 - 52 schistosome cercariae once every other day for 5 times,infection, followed by the repeated dosing every 1 or 2 wk for 2 - 3 times. RESULTS: After above mentioned dogs or rabbits were treated ig with Art,ArtC or Pra, the female worm reduction rates were 92.1% - 100 %. Histopathological examination showed that the reduction rates of total granuloma in the liver sections of the dogs and rabbits were 70.9 % - 97.3 % and 76.5 % - 97.4 %, respectively. Meantime, the structure of the hepatic lobules was normal with normal arrangement of the liver bundle. CoNCLusIoNS: Early treatment with Art or Pra exhibited a promising effect of protection of the liver of the dogs and rabbits infected with schistosome cercariae.%观察感染血吸虫尾蚴后早期用蒿甲醚(Art)或吡喹酮(Pra)治疗,对宿主肝组织的影响.方法:犬感染198-202条尾蚴后d 7ig Art 10 mg·kg-1,Art胶囊(ArtC)15 mg·kg-1或感染后d 21ig Pra 30-40 mg·kg-1,1-2 wk重复给药1次,共2-4次;兔每隔日感染48-52条尾蚴,共5次,并于第1次感染后d 7或d 21 ig 上述剂量的Art和Pra,停药后4-5 wk剖杀取肝作切片观察.结果:犬与兔经Art或Pra早期治疗后,减♀虫率达92.1%-100%,肝切片中的总虫卵肉芽肿数分别减少70.9%-97.3%和76.5%-97.4%,肝叶结构和肝索排列正常.结论:2种药物早期治疗对宿主肝脏有保护作用.

  12. Alternatively Activated Mononuclear Phagocytes from the Skin Site of Infection and the Impact of IL-4Rα Signalling on CD4+T Cell Survival in Draining Lymph Nodes after Repeated Exposure to Schistosoma mansoni Cercariae

    Science.gov (United States)

    Prendergast, Catriona T.; Sanin, David E.; Mountford, Adrian P.

    2016-01-01

    In a murine model of repeated exposure of the skin to infective Schistosoma mansoni cercariae, events leading to the priming of CD4 cells in the skin draining lymph nodes were examined. The dermal exudate cell (DEC) population recovered from repeatedly (4x) exposed skin contained an influx of mononuclear phagocytes comprising three distinct populations according to their differential expression of F4/80 and MHC-II. As determined by gene expression analysis, all three DEC populations (F4/80-MHC-IIhigh, F4/80+MHC-IIhigh, F4/80+MHC-IIint) exhibited major up-regulation of genes associated with alternative activation. The gene encoding RELMα (hallmark of alternatively activated cells) was highly up-regulated in all three DEC populations. However, in 4x infected mice deficient in RELMα, there was no change in the extent of inflammation at the skin infection site compared to 4x infected wild-type cohorts, nor was there a difference in the abundance of different mononuclear phagocyte DEC populations. The absence of RELMα resulted in greater numbers of CD4+ cells in the skin draining lymph nodes (sdLN) of 4x infected mice, although they remained hypo-responsive. Using mice deficient for IL-4Rα, in which alternative activation is compromised, we show that after repeated schistosome infection, levels of regulatory IL-10 in the skin were reduced, accompanied by increased numbers of MHC-IIhigh cells and CD4+ T cells in the skin. There were also increased numbers of CD4+ T cells in the sdLN in the absence of IL-4Rα compared to cells from singly infected mice. Although their ability to proliferate was still compromised, increased cellularity of sdLN from 4x IL-4RαKO mice correlated with reduced expression of Fas/FasL, resulting in decreased apoptosis and cell death but increased numbers of viable CD4+ T cells. This study highlights a mechanism through which IL-4Rα may regulate the immune system through the induction of IL-10 and regulation of Fas/FasL mediated cell death

  13. 日本血吸虫尾蚴及童虫可溶性抗原蛋白质组研究%The soluble antigenic proteome of Schistosoma japonicum cercariae and schistosmula

    Institute of Scientific and Technical Information of China (English)

    马安; 王越; 汤益; 杨再峰; 施晓华; 朱明东; 刘晓龙; 干小仙

    2011-01-01

    应用免疫蛋白质组研究方法筛选、鉴定日本血吸虫尾蚴、童虫可溶性抗原蛋白质。方法日本血吸虫尾蚴可溶性粗抗原(SCAP)、童虫可溶性粗抗原(SLAP)分别用双向凝胶电泳(2-DE)分离蛋白质,每样本同时制3块胶,1块胶进行银染,2块胶通过电转印后再分别用感染兔和正常兔血清作Western印迹分析,确定特异性阳性反应点,再从相应银染胶图上找到匹配的抗原蛋白质点;用MALDI-TOF/TOF串联质谱鉴定抗原蛋白质。结果SCAP、SLAP与感染兔血清免疫反应分别获得94个和68个阳性点,在相应的银染胶图上分别获得33个和31个匹配蛋白质点;用MALDI-TOF/TOF串联质谱鉴定和NCBI数据库检索,鉴定成功率分别为100.0%(20/20)和68.2%(15/22)。已获鉴定的SCAP抗原中蛋白酶占62.5%(10/16),SLAP抗原中蛋白酶占36.4%(4/11);2个抗原蛋白为SCAP和SLAP共有。结论2-DE能有效地分离日本血吸虫可溶性抗原蛋白质,2-D Western印迹法能较好地筛选特异性抗原;2-D Western印迹法阳性点与2-DE胶图蛋白质点匹配率低,低丰度的抗原蛋白质易被漏检;尾蚴和童虫的抗原蛋白质组差异较大。%Objective To screen and identify specific antigenic proteins of Schistosoma japonicum cercariae and schistosomula using immunproteomics approaches. Methods Soluble antigenic proteins of Schistosoma japonicun cercarie (SCAP) and 15 days lung-stage schistosomulum (SLAP) were separated by two-dimensional electrophoresis (2-DE). For each sample, three gels were run in parallel with one gel for silver stain and the other two gels for Western blot using Schistosoma japonicum infected rabbit sera and normal rabbit sera separately. The specific antigenic protein spots were determined on the membrane of Western blot. The matched antigenic protein spots on the sliver stained gels were subsequently analysed by MALDI-TOF/TOF-MS/MS respectively. Results 94 and 68 positive

  14. Schistosoma mansoni: aspectos quantitativos da fertilidade e sobrevida de vermes oriundos de cercárias irradiadas com 3 Krad, em camundongos Schistosoma mansoni: quantitative aspects of the fertility and survival of worms obtained from irradiated cercariae (3 Krad, in mice

    Directory of Open Access Journals (Sweden)

    Gileno de Sá Cardoso

    1990-02-01

    Full Text Available Quatro grupos de camundongos albinos (Mus musculus não isogênicos foram infectados transcutaneamente com cerca de 450 cercárias (das cepas LE e SJ do S. mansoni não irradiadas (grupos controles e irradiadas com 3 Krad de radiação gama proveniente de cobalto-60, com a finalidade de observar o efeito da irradiação gama sobre a fertilidade das fêmeas e a sobrevida dos vermes no sistema porta. A partir do 33º dia ocorre uma certa estabilidade na população dos vermes sobreviventes, ficando esta população constante, notadamente em relação à cepa LE, até o final das observações (90º dia. Concluiu-se que esta dose de radiação gama impede a produção de ovos dos vermes em 98,1% dos camundongos infectados, sendo mortos todos os ovos detectados; as fêmeas são mais resistentes à irradiação e o efeito desta sobre a mortalidade dos machos somente se torna estatisticamente significativo a partir do 61º dia de infecção. O longo tempo de permanência de vermes adultos irradiados estéreis no sistema porta de camundongos e o seu provável envolvimento no desenvolvimento de imunoproteção, tipo imunidade concomitante sem as implicações imunopatológicas para o hospedeiro, são discutidos nesse trabalho.The effect of gamma irradiation on the fertility of female mice, as well as the survival of worms in their portal system, have been observed in four groups of outbred albino mice (Mus musculus, experimentally infected with ca 450 cercariae of Schistosoma mansoni (LE and SJ strains, by transcutaneous route. The cercariae used were a non-irradiated (control groups, and b irradiated with 3 Krad of gamma irradiation (Co-60. From the 33rd day on, some estability in the population of surviving worm could be observed. This population remained constant till the end of the observation period (90th day, notedly in relation to the LE strain. Thus, it was concluded that gamma irradiation (at the dose of 3 Krad is able to hinder the worm egg

  15. Synthesis of new 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine derivatives with an incorporated thiazolidinone moiety and testing their possible serine protease and cercarial elastase inhibitory effects with a possible prospective to block penetration of Schistosoma mansoni cercariae into the mice skin.

    Science.gov (United States)

    Bahgat, Mahmoud Mohamed; Maghraby, Amany Sayed; Heiba, Mogeda Emam; Ruppel, Andreas; Fathalla, Omar Abd-elfattah Mohamed

    2005-09-01

    5-Substituted 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine were synthesized by interaction of 4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonylhydrazide with some aldehydes to give the corresponding Schiff-bases, which after cyclization gave corresponding thiazolidinones. For some of the thiazolidinones, Mannich bases reaction was carried out. All the derivatives were tested for their possible inhibitory effect on Schistosoma mansoni cercarial elastase (CE). Only, N-(4-methylbenzyledine)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-sulfonylhydrazide was found to have potent inhibitory effect on the CE activity with IC50 = 264 microM. Upon its use as a paint for mice tails before infection with S. mansoni cercariae, the compound formulated in jojoba oil caused a significant reduction (93%; P-value = 0.0002) in the worm burden. IgG & IgM in mice sera were measured by using several S. mansoni antigens by ELISA. Sera from treated infected mice (TIM) 2, 4, and 6 weeks (W) post infection (PI) showed 1.2 folds lower, 1.2 folds higher, 1.7 folds lower IgM reactivity against soluble cercarial antigenic preparation (CAP), respectively, when compared with sera collected from infected untreated mice (IUM). Sera from TIM 2, 4, and 6WPI showed 1.3, 1.6, and 1.7 folds higher IgG reactivity, respectively against CAP than the IgG reactivity from IUM. Sera from TIM 2, 4 and 6WPI showed 1.5, 1.2 folds lower and 1.4 folds higher IgM reactivity, respectively against soluble worm antigenic preparation (SWAP) when compared with sera collected from IUM. Sera from TIM 2, 4, and 6WPI showed 1.4, 1 folds lower and 1 fold higher IgG reactivity, respectivley to SWAP when compared with sera from IUM. Sera from TIM 2, 4, and 6WPI had generaly lower IgM and IgG reactivities against soluble egg antigen (SEA) when compared with sera from IUM.

  16. Purification and characterization of an elastinolytic proteinase secreted by cercariae of Schistosoma mansoni.

    Science.gov (United States)

    McKerrow, J H; Pino-Heiss, S; Lindquist, R; Werb, Z

    1985-03-25

    An elastinolytic proteinase secreted by tissue-invasive larvae of Schistosoma mansoni has been purified to homogeneity. Size-exclusion chromatography and chromatofocusing were used to purify the enzyme 18-fold from crude larval secretions. The native enzyme has a molecular weight of 30,000, a pI of 8, a pH optimum of 9, and a calcium dependence of 2 mM. A second Mr 17,000 form of the enzyme was present in crude secretions and appears to be an autoproteolysis product. The enzyme is a serine proteinase that preferentially binds tetrapeptide inhibitors or substrates with an aromatic or hydrophobic residue at the P-1 site. In addition to being active against elastin, the enzyme degrades Azocoll, gelatin, laminin, fibronectin, keratin, and type IV collagen.

  17. Tissue reactions in lambs and kids vaccinated with irradiated and normal amphistome metacercariae (Cercariae indicae XXVI)

    International Nuclear Information System (INIS)

    The intensity of gross and histopathological changes were inversely related to the dose of irradiation. Severe catarrhal enteritis was noticed with non-irradiated metacercariae while with increased irradiation doses the intensity of changes were in decreasing order, however, with 3 Krad dose no severe change was seen. The severe changes of gastro-enteritic lesions were seen from the challenge dose of normal metacercariae in the lambs and kids previously vaccinated with non-irradiated metacercariae. The moderate catarrhal enteritis, mild necrotic lesions and absence of severe lesions produced by the challenge dose of normal metacercariae in the lambs and kids previously vaccinated with 2, 2.5 and 3 Krad level of irradiated metacercariae suggested that the lesions produced by challenge doses were in order of reduced intensity as the dose of irradiation for initial vaccination increased. The cellular infiltration with round cells, plasma cells and macrophages in the mucosa of the small intestine was more in lambs and kids vaccinated with irradiated metacercariae and the order of increase was in correspondent with the level of irradiation. The present study showed that the optimal dose of irradiation for amphistome metacercariae was 3 Krad, where maximum immunological response could be obtained. This also suggests the possibility of immunizing lambs and kids against intestinal amphistomiasis with 3 Krad irradiated metacercariae. (author)

  18. A protease-based biosensor for the detection of schistosome cercariae.

    Science.gov (United States)

    Webb, A J; Kelwick, R; Doenhoff, M J; Kylilis, N; MacDonald, J T; Wen, K Y; McKeown, C; Baldwin, G; Ellis, T; Jensen, K; Freemont, P S

    2016-01-01

    Parasitic diseases affect millions of people worldwide, causing debilitating illnesses and death. Rapid and cost-effective approaches to detect parasites are needed, especially in resource-limited settings. A common signature of parasitic diseases is the release of specific proteases by the parasites at multiple stages during their life cycles. To this end, we engineered several modular Escherichia coli and Bacillus subtilis whole-cell-based biosensors which incorporate an interchangeable protease recognition motif into their designs. Herein, we describe how several of our engineered biosensors have been applied to detect the presence and activity of elastase, an enzyme released by the cercarial larvae stage of Schistosoma mansoni. Collectively, S. mansoni and several other schistosomes are responsible for the infection of an estimated 200 million people worldwide. Since our biosensors are maintained in lyophilised cells, they could be applied for the detection of S. mansoni and other parasites in settings without reliable cold chain access. PMID:27090566

  19. Antigen localization and the induction of resistance in mice vaccinated with irradiated cercariae of Schistosoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Mountford, A.P.; Coulson, P.S.; Wilson, R.A.

    1988-08-01

    The fate of /sup 75/Se-labelled parasites and their released pre-synthesized macromolecules has been followed in three murine infection models. Marked differences were found between the three models. The pattern of migration of normal schistosomula was similar to that previously reported. In addition we have described the transit of parasites through the lymph nodes draining the infection site. Significant quantities of released material were detected in the skin, draining lymph nodes, bloodstream and liver. The circulating material was of parasite origin, macromolecular, and hence potentially antigenic. In comparison to the normal infection, radiation-attenuated parasites (inducing a high level of resistance to challenge) persisted in the skin, draining lymph nodes and lungs, releasing a proportionally greater amount of material in the nodes. In mice exposed to attenuated parasites and treated with the compound RO11-3128 at 24 h (inducing a low level of resistance) there was an early death and rapid clearance of the parasites whilst still in the skin. This situation resulted in the highest levels of released material in the skin, bloodstream and liver, but negligible levels in the draining lymph nodes. We suggest that the persistence of radiation-attenuated parasites in the skin and draining lymph nodes, together with the prolonged release of antigen in the latter site, compared to the normal situation, are major factors in the induction of resistance.

  20. Autoradiographic quantification of the efficacy of niridazole in mice infected with (75)Se-labelled cercariae of Schistosoma mansoni

    International Nuclear Information System (INIS)

    Integrated vector management (IVM) for malaria control requires ecological skills that are very scarce and rarely applied in Africa today. Partnerships between communities and academic ecologists can address this capacity deficit, modernize the evidence base for such approaches and enable future scale up. Community-based IVM programmes were initiated in two contrasting settings. On Rusinga Island, Western Kenya, community outreach to a marginalized rural community was achieved by University of Nairobi through a community-based organization. In Dar es Salaam, Tanzania, Ilala Municipality established an IVM programme at grassroots level, which was subsequently upgraded and expanded into a pilot scale Urban Malaria Control Programme with support from national academic institutes. Both programmes now access relevant expertise, funding and policy makers while the academic partners benefit from direct experience of community-based implementation and operational research opportunities. The communities now access up-to-date malaria-related knowledge and skills for translation into local action. Similarly, the academic partners have acquired better understanding of community needs and how to address them. Until sufficient evidence is provided, community-based IVM remains an operational research activity. Researchers can never directly support every community in Africa so community based IVM strategies and tactics will need to be incorporated into undergraduate teaching programmes to generate sufficient numbers of practitioners for national scale programmes. Academic ecologists at African institutions are uniquely positioned to enable the application of practical environmental and entomological skills for malaria control by communities at grassroots level and should be supported to fulfil this neglected role

  1. The magnitude and kinetics of delayed-type hypersensitivity responses in mice vaccinated with irradiated cercariae of Schistoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Ratcliffe, E.C.; Wilson, R.A. (York Univ. (United Kingdom). Dept. of Biology)

    1991-08-01

    A footpad assay was used to measure the DTH of mice to soluble worm antigens (SWAP), and to living day 7 lung schistosomula, following vaccination and challenge infections with Schistosoma mansoni. DTH to SWAP was first observed on day 10, and reached its maximum on day 17 post-vaccination. Treatment of mice with anti-CD4 antibody on the 3 days prior to footpad challenge completely abrogated this response. Reactivity to living parasites was of a slower order than that to SWAP; it also peaked earlier, on day 10 post-vaccination. By day 35, responsiveness to both sets of antigens had declined almost to control levels. There was no correlation between the level of DTH to living schistosomula, at any time, and the degree of resistance subsequently developed. Percutaneous challenge of vaccinated mice was followed by a resurgence of reactivity to SWAP. This secondary response occurred more rapidly than the primary response, peaking on day 7 post-challenge, and was of a similar magnitude. We were unable to detect a similar recall of DTH to living schistosomula, possibly because the assay was insufficiently sensitive. We conclude that the intensity and kinetics of DTH responsiveness are crucial features of the irradiated vaccine model, and suggest that further investigation of cell-mediated immune reaction, particularly those occuring in the lungs, is vital to a better understanding of events underlying the development and expression of immunity. (author).

  2. Comparison of Th1- and Th2-associated immune reactivities stimulated by single versus multiple vaccination of mice with irradiated Schistosoma mansoni cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Caulada-Benedetti, Z.; Al-Zamel, F.; Sher, A.; James, S. (NIAID, Bethesda, MD (USA))

    1991-03-01

    Mice immunized against Schistosoma mansoni by a single percutaneous exposure to radiation-attenuated parasite larvae demonstrate partial resistance to challenge infection that has been shown to correlate with development of cell-mediated immunity, whereas mice hyperimmunized by multiple exposure to attenuated larvae produce antibodies capable of transferring partial protection to naive recipients. Measurement of Ag-specific lymphokine responses in these animals suggested that the difference in resistance mechanisms may be due to the differential induction of Th subset response by the two immunization protocols. Thus, upon Ag stimulation, singly immunized mice predominantly demonstrated responses associated with Th1 reactivity, including IL-2 and IFN-gamma production, whereas multiply immunized animals showed increased IL-5, IL-4, and IgG1 antibody production associated with enhanced Th2 response. These responses demonstrated some degree of organ compartmentalization, with splenocytes demonstrating higher Th1-related lymphokine production and cells from draining lymph nodes showing stronger proliferation and Th2 type reactivity. However, hyperimmunized mice also continued to demonstrate substantial Th1-associated immune reactivity. Moreover, in vivo Ag challenge elicited activated larvacidal macrophages in hyperimmunized animals. These observations indicate that protective cell-mediated mechanisms associated with induction of CD4+ Th1 cell reactivity predominate in singly vaccinated mice. Further vaccination stimulates Th2 responses, such as enhanced IgG1 production, that may also contribute to protective immunity.

  3. SCANNING ELECTRON MICROSCOPY OF REDIA AND CERCARIA OF FASCIOLA HEPATICA%肝片形吸虫雷蚴与尾蚴的扫描电镜观察

    Institute of Scientific and Technical Information of China (English)

    杨光友; 沙国润; 张同富; 李英

    2001-01-01

    肝片形吸虫的母雷蚴、早期子雷蚴、成熟子雷蚴及尾蚴表被结构经扫描电镜观察:在母雷蚴及早期子雷蚴的口孔周围有乳突分布;雷蚴的围领呈领圈样环绕,围领基部的一侧有一个产孔,产孔的开口处呈唇样的构造.从母雷蚴、早期子雷蚴至成熟子雷蚴的发育,其体表绒毛样构造日趋发达.尾蚴背部密布尖刀形棘,腹部具有许多不规则的突起,其间分布有许多微孔;口吸盘及周围无乳突分布,但在腹吸盘周围分布有排列整齐的指状突起.尾蚴体部与尾部相连处有一环形颈状结构,尾蚴尾干背面为一槽状的皱襞.

  4. Epidemiology of cercarial stage of trematodes in freshwater snails from Chiang Mai province, Thailand

    Institute of Scientific and Technical Information of China (English)

    Thapana Chontananarth; Chalobol Wongsawad

    2013-01-01

    Objective: To investigate the epidemiological situation of cercarial trematodes infection in freshwater snails from different water resources in Chiang Mai province, Thailand. Methods:The snail specimens were collected from 13 districts of Chiang Mai province during April 2008 to February 2012. The prevalence of cercarial infection in snails was investigated using the crushing method. The drawing was done with the help of a camera lucida for the morphological study. Results:A total of 2 479 snail individuals were collected and classified into 7 families, 11 genera, and 14 species, Among them, 8 snails species were found to be infected with an overall prevalence of 17.27% (428/2 479), which infected with nine groups of cercariae;gymnocephalous cercaria, strigea cercaria, megalurous cercaria, monostome cercaria, parapleurolophocercous cercaria (Haplorchis cercaria), pleurolophocercous cercaria, furcocercous cercaria (Transversotrema cercaria), xiphidiocercaria, and virgulate cercaria. The parapleurolophocercous cercaria was found to be the dominant type among the cercarial infection in the snails (64.25%). Conclusions:The various species of snails found in the research location act as the intermediate hosts for the high prevalence of parasitic infection of many species of mammals. This work will provide new information on both the distribution and first intermediate host of trematodes.

  5. Formation of Fasciola hepatica cercaria to metacercaria after escaped from Galba pervia%肝片吸虫尾蚴自小土蜗逸出及其形成囊蚴过程的观察

    Institute of Scientific and Technical Information of China (English)

    张翠阁

    2000-01-01

    @@ 肝片吸虫(Fasciola hepatica Linnaeus,1758)是寄生于牛、羊等哺乳动物胆道,损害肝脏,甚至引起死亡的大型吸虫,对畜牧业发展有重要影响.为了了解其生物学特性,有利于开展防治研究,我们曾实验观察了肝片吸虫尾蚴自中间宿主小土蜗(Galba pervia)逸出及其囊蚴形成的过程,简报如下. 实验在夏季进行.将实验感染肝片吸虫毛蚴后30天以上的小土蜗采集回室内,分养在100 ml的小烧杯内.每个烧杯加水70ml、放小土蜗3-5个,并定时观察.文献记载,肝片吸虫毛蚴自中间宿主逸出和囊蚴形成都是在夜间.笔者有两次在下午观察到尾蚴逸出和囊蚴形成.

  6. [Diversity of trematode larvae in gastropod molluscs in water bodies of Belarus].

    Science.gov (United States)

    Akimova, L N; Shimalova, V V; Bychkova, E I

    2011-01-01

    The analysis of literary data and own investigations of gastropod molluscs on existence of cercariae of trematodes in Belarus was carried out. 13 856 specimens of 11 species and 2 species complexes of freshwater gastropod molluscs were examined on infection with cercariae of trematodes in 2010 by the authors of this article. Total infestation was 13.1% and infection of some molluscs species varied from 0.4% (Dnieper River, Gomel region) to 66.7% (Lukomskoe reservoir, Vitebsk region). The cercariae of 90 trematode species were found. The majority (51 species) at the adult stage parasitize birds. The cercariae of 14 trematode species have medical significance.

  7. La queratotaxia cercariana en la diferenciacion de sexos de schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Luz Arelis Pino

    1988-09-01

    Full Text Available El número de papilas argirófilas superficiales y su modelo de disposición en el tegumento de las cercarias (quetotaxia de Schistosoma mansoni nos permitió diferenciar los sexos a nivel del mencionado estadío larvario, mediante los siguientes critérios: - Mayor homogeneidad en las cercarias machos, en cuanto al número total de papilas ventrales y dorsales a nivel de cuerpo y cola cercarianos (C.V. = 4,1%, que en las cercarias hembras (C. V. = 18,3% (P < 0,001. - Presencia en el 80% de las cercarias machos de cuatro papilas en los cuadrantes "C" ó "D" inferior-izquierdo e inferior-derecho, respectivamente ventrales, mientras que dicho caracter sólo está presente en el 40% de las cercarias hembras (P < 0,001. - Diferencia estadísticamente significativa (P < 0,001 entre el número total promedio de papilas corporales centrales de las cercarias hembras (X = 11,9 ± 0,2 y el de las cercarias machos (X = 11,1 ± 0,3. - Diferencia estadísticamente significativa (P < 0,05 para la mayor distancia promedio entre las papilas AIL y AIIL, de cada cercaria, en relación con el sexo (femenino = 25,5 µm ± 0,33; masculino = 27,3 µm ± 0,26.

  8. 血吸虫对吡喹酮抗药性的研究 Ⅲ 曼氏血吸虫吡喹酮敏感株与抗性株尾蚴对吡喹酮的反应性%STUDIES ON RESISTANCE OF SCHISTOSOMA TO PRAZIQUANTEL Ⅲ. RESPONSE OF CERCARIAE OF PRAZIQUANTEL-RESISTANT AND -SUSCEPTIBLE SCHISTOSOMA MANSONI TO PRAZIQUANTEL

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    目的比较曼氏血吸虫吡喹酮敏感株与抗性株尾蚴阶段对吡喹酮的反应性,旨在运用敏感株与抗性株反应性间的差异,建立现场监测吡喹酮抗性的方法.方法将各虫株尾蚴分别暴露于10-4、10-5、6×10-7、4×10-7 mol/L吡喹酮溶液中,0、20、40、60、80、100 min后,解剖镜下观察尾蚴的泳动、收缩和断尾率的变化.结果尾蚴暴露于10-4 mol/L吡喹酮中即刻停止泳动、沉底并伴有强直性收缩;5 min 后开始出现体与尾部不协调的快速蠕动,尾蚴体区的后端与尾部的前端发生分离即断尾,敏感株断尾尾蚴明显多于抗性株;暴露于10-5 mol/L吡喹酮中40、60、80 min和100 min 后,敏感株尾蚴的断尾率分别为28.2%、52.7%、67.5%和78.0%;抗性株分别为11.3%、28.6%、39.3%和45.5%.暴露于4×10-7 mol/L中80 min和100 min 后,敏感株尾蚴的断尾率为10.3 %和17.0%;抗性株为0.5%和1.1%.结论曼氏血吸虫吡喹酮抗性株和敏感株尾蚴阶段对吡喹酮反应性存在非常显著的差异.提示,将尾蚴移入4×10-7 mol/L吡喹酮溶液中80-100 min,镜下观察其断尾率,作为曼氏血吸虫对吡喹酮敏感性的检测方法,可用于螺体内吡喹酮抗性虫株的现场监测.

  9. Life cycle and structure of the fish digenean Brachyphallus crenatus (Hemiuridae).

    Science.gov (United States)

    Køie, M

    1992-04-01

    Cystophorous cercariae from Retusa obtusa (Montagu) (Gastropoda, Opisthobranchia, Retusidae) develop into adults of Brachyphallus crenatus (Rudolphi, 1802) Odhner, 1905 (Hemiuridae). The free-swimming cercariae were ingested by laboratory-reared Acartia tonsa Dana, and the cercarial body was injected into the hemocoel of the copepod. Two-week-old metacercariae held at 15 C were infective to stickleback Gasterosteus aculeatus Linnaeus. The cercariae of B. crenatus are very similar to the cercariae of Hemiurus luehei Odhner, 1905, and Lecithocladium excisum (Rudolphi, 1819) Lühe, 1901 (Hemiuridae), which develop in closely related opisthobranch snails. Scanning electron microscopy of metacercariae and adults of B. crenatus revealed the annular plications of most of the external surface to be scalelike. The area surrounding the genital pore and the presomatic pit was densely plicated. PMID:1556648

  10. Haplometra cylindracea (Zeder, 1800 (Trematoda: Plagiorchiidae: variation in the dates of cercarial shedding for overwintering Galba truncatula

    Directory of Open Access Journals (Sweden)

    Vignoles P.

    2011-05-01

    Full Text Available Natural infections of Galba truncatula with Haplometra cylindracea were followed from 2001 to 2009 to determine if their characteristics were similar when snails came from water collections frequented by Bufo bufo or by frogs and newts for their egg-laying. Snail samples were collected from both types of sites to count shed cercariae for three days and also free cercariae when snails were dissected. In sites only frequented by B. bufo, cercarial shedding occurred earlier than in those colonized by frogs and newts (March instead of April-May. In contrast, the number of cercariae shed during three successive days was significantly higher in May. This variation in the dates of cercarial shedding might be due, either to a synchronism between cercaria-releasing snails and the presence of the definitive host (tadpoles in water collections, or to an earlier infection of overwintering snails in autumn by H. cylindracea miracidia in the case of toad-frequented sites.

  11. Chronic pathology and longevity of Drepanocephalus spathans infections in juvenile channel catfish

    Science.gov (United States)

    Drepanocephalus spathans (Digenea: Echinostomatidae) is a common parasite of the double-crested cormorant (Phalacrocorax auritus). The cercariae of D. spathans have been shown infective to juvenile channel catfish (Ictalurus punctatus). The developing metacercariae concentrate in the cranial regio...

  12. The neuro-muscular system in fresh-water furcocercaria from Belarus. I Schistosomatidae.

    Science.gov (United States)

    Tolstenkov, Oleg O; Akimova, Ludmila N; Chrisanfova, Galina G; Terenina, Nadezhda B; Gustafsson, Margaretha K S

    2012-01-01

    The neuro-muscular system (NMS) in cercariae of the family Schistosomatidae from Belarus was studied with immunocytochemical methods and confocal scanning laser microscopy. The specimens of Bilharziella polonica were compared with Trichobilharzia szidati and Trichobilharzia franki. The patterns of F-actin in the musculature, 5-HT-immunoreactive (IR), FMRFamide-IR neuronal elements and α-tubulin-IR in sensory receptors and nerves were investigated. No indications of structural differences in the musculature, the 5-HT-IR, FMRF-IR neuronal elements and the general distribution of sensory receptors were noticed between cercariae of Trichobilharzia spp. The number of 5-HT-IR neurons in the cercarial bodies is 16. In cercaria B. polonica, the tail musculature is weaker than in Trichobilharzia spp. A detailed schematic picture of the NMS in the tail of Trichobilharzia spp. cercaria is given. The function of NMS elements in the tail is discussed.

  13. Larval trematodes (Digenea of the great pond snail, Lymnaea stagnalis (L., (Gastropoda, Pulmonata in Central Europe: a survey of species and key to their identification

    Directory of Open Access Journals (Sweden)

    Faltýnková A.

    2007-03-01

    Full Text Available A survey of cercariae and metacercariae (Trematoda, Digenea from the great pond snail (Lymnaea stagnalis in Central Europe (Austria, Czech Republic, South-East Germany, Poland and Slovak Republic is presented, based on a study of 3,628 snails examined from 1998 to 2005. A total of 953 (26.3% L. stagnalis were infected with 24 trematode species comprising 19 species of cercariae and 11 species of metacercariae (six species occurred both as cercarie and metacercarie of eight families. The dominant cercariae were those of Opisthioglyphe ranae (159 hosts infected, Plagiorchis elegans (141 (both family Plagiorchiidae and Echinoparyphium aconiatum (153 (Echinostomatidae; 14 double infections were found. The most frequent metacercariae were those of Neoglyphe locellus (71 (Omphalometridae, E. aconiatum (66, Echinostoma sp. (59 and Moliniella anceps (48 (Echinostomatidae. In the previous studies carried out in Central Europe, a very similar spectrum of nine trematode families of 22 cercariae determined to species level and 43 types of cercariae reported under generic or provisional names, which can be in many cases conspecific with the previous taxa, were found. A simple key to identification of cercariae and metacercariae, together with their illustrations, is provided.

  14. Experimental Life Cycle of Hypoderaeum conoideum (Block, 1872 Diez, 1909(Trematoda: Echinostomatidae Parasite from the North of Iran

    Directory of Open Access Journals (Sweden)

    Hakim AZIZI

    2015-03-01

    Full Text Available Background: Human Echinostomiasis is an intestinal disease caused by the members of family Echinostomatidae parasites. The aim of present research was to identify echinos­tomatidae cercariae emitted by Lymnaea palustris snails from Mazandaran province in the north of Iran based on the morphological and morphometrical charac­teristics of the different stages of experimental parasite life cycle.Methods: Echinostomatidae cercariae were collected from L. palustris (Gastropoda: Lymnaeidae of the north of Iran. To collect metacercaria, 50 healthy snails were infected with cercariae experimentally (50 cercariae for each. To obtain the adult stage, 9 laboratory animals (3 ducks, 2 rats, 2 mice and 2 quails were fed with 60 metacercaria for each. To identify parasite, the different stages of worm were exam­ined using light microscope and then the figures were draw under camera Lucida microscope and measures were determined.Results: Averagely, 15metacercaria were obtained from each snail that had been previously exposed with cercariae. Ducks presented worm eggs in feces after 10-15 days post-infection. Intestinal worms were collected and identified as Hypoderaeum conoideum on the bases of figures and measures of cephalic collar, the number of collar spine, suckers diameter ratio, testes arrangement, etc.Conclusion: H. conoideum cercariae and adult worm are described. This is the first report of the different stages of the experimental life cycle of this parasite in Iran.

  15. Studies on resistance of Schistosoma to praziquantel Ⅻ Comparison of susceptibility between male and female cercariae of praziquantel resistant and susceptible isolates of Schistosoma mansoni to praziquantel%血吸虫对吡喹酮抗药性的研究Ⅻ曼氏血吸虫吡喹酮敏感株和抗性株雌雄尾蚴对吡喹酮敏感性的比较

    Institute of Scientific and Technical Information of China (English)

    梁幼生; M. J. Doenhoff; 戴建荣; 李洪军; 汪伟; 陶永辉; 张键锋; 李伟; 朱荫昌; G. C. Coles

    2007-01-01

    目的 比较曼氏血吸虫吡喹酮敏感株、抗性株雌性与雄性尾蚴对吡喹酮敏感性的差异,为探索血吸虫对吡喹酮抗性产生机制提供线索.方法 分别用曼氏血吸虫吡喹酮敏感株、抗性株感染鼠粪便中的虫卵孵化毛蚴,以单只毛蚴感染单只光滑双脐螺,建立单性别血吸虫尾蚴系;以W1特异性序列为引物,采用直接PCR法鉴别出单性别系尾蚴的性别,分别将敏感株与抗性株的雌、雄尾蚴暴露于不同浓度的吡喹酮溶液中,经一定时间后观察并计算尾蚴的断尾率.结果 曼氏血吸虫尾蚴暴露于10-4、10-5、6×10-7mol/L和4×10-7mol/L吡喹酮溶液中100 min,吡喹酮敏感株雄性尾蚴的断尾率分别为66.7%、75.8%、43.5%和21.7%,雌性的断尾率分别为29.3%、27.9%、12.1%和7.6%,雄性尾蚴的断尾率显著高于雌性尾蚴(P均<0.05),而抗性株雄性尾蚴的断尾率分别为43.3%、39.4%、25.4%和6.9%,雌性尾蚴的断尾率分别为47.0%、38.9%、26.3%和6.3%,两者间差异无统计学意义(P均>0.05).曼氏血吸虫尾蚴分别暴露于10-4、10-5、6×10-7 mol/L和4×10-7mol/L吡喹酮溶液中80 min,敏感株雄性尾蚴的断尾率分别为54.4%、68.6%、42.1%和16.1%,抗性株雄性尾蚴的断尾率分别为30.2%、34.4%、20.1%和2.8%,敏感株显著高于抗性株(P均<0.05).结论 曼氏血吸虫雌雄尾蚴对吡喹酮的敏感性存在差异,雄性尾蚴敏感性高于雌性.曼氏血吸虫吡喹酮抗性的产生与雄虫对吡喹酮的敏感性降低有关.

  16. Environmental Epidemiology of Intestinal Schistosomiasis in Uganda: Population Dynamics of Biomphalaria (Gastropoda: Planorbidae in Lake Albert and Lake Victoria with Observations on Natural Infections with Digenetic Trematodes

    Directory of Open Access Journals (Sweden)

    Candia Rowel

    2015-01-01

    Full Text Available This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P<0.001 in both lakes and negative relationship with conductivity (P=0.04 in Lake Albert. Of the Biomphalaria collected in Lake Albert N=6,183, 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria  N=13,172 were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene.

  17. The identification and characteristics of Echinoparyphium rubrum (Cort. 1914) new comb. (Trematoda, Echinostomatidae) based on experimental evidence of the life cycle

    Science.gov (United States)

    1998-01-01

    The life cycle of Echinoparyphium rubrum (Cort, 1914) comb. n. has been completed experimentally. All of the developmental stages egg, miracidium, sporocyst, mother and daughter rediae, cercaria, metacercaria, and adult were examined and described. The miracidia infected freshwater snails of the genus Physa , P. gyrina and P. occidentalis. Attempts to infect snails of the genera Lymnaea, L. auricularis, L. peregra, L. truncatula and Bulinus, B. truncatus failed. Cercariae infected various pulmonate and prosobranch freshwater snails, mussels, frogs, water turtles and planarians. The adults developed in the small intestine of birds and mammals. The identity and major characteristics of Echinoparyphium rubrum are discussed. Synonyms of E. rubrum are Cercaria rubra Cort, 1914; Cercaria biflexa Faust, 1917; Cercaria chisolenata Faust, 1918; Echinostoma callawayensis Barker et Noll, 1915; Echinostoma revolutum of Johnson (1920); Echinoparyphium elegans of Cannon (1938), of Bain and Trelfall (1977), of Mahoney and Trelfall (1977); and Echinoparyphium recurvatum of Jilek (1977), Harley (1972), Sankurathri and Holmes (1976). Comparisons are made between E. rubrum and its 43-collar-spined allies: E. flexum from North America, E. cinctum from Europe, E. dunni from Asia and E. elegans from Africa.

  18. Combined Effects of Pesticides and Trematode Infections on Hourglass Tree Frog Polypedates cruciger.

    Science.gov (United States)

    Jayawardena, Uthpala A; Rohr, Jason R; Navaratne, Ayanthi N; Amerasinghe, Priyanie H; Rajakaruna, Rupika S

    2016-03-01

    The impact of widespread and common environmental factors, such as chemical contaminants, on infectious disease risk in amphibians is particularly important because both chemical contaminants and infectious disease have been implicated in worldwide amphibian declines. Here we report on the lone and combined effects of exposure to parasitic cercariae (larval stage) of the digenetic trematode, Acanthostomum burminis, and four commonly used pesticides (insecticides: chlorpyrifos, dimethoate; herbicides: glyphosate, propanil) at ecologically relevant concentrations on the survival, growth, and development of the common hourglass tree frog, Polypedates cruciger Blyth 1852. There was no evidence of any pesticide-induced mortality on cercariae because all the cercariae successfully penetrated each tadpole host regardless of pesticide treatment. In isolation, both cercarial and pesticide exposure significantly decreased frog survival, development, and growth, and increased developmental malformations, such as scoliosis, kyphosis, and also edema and skin ulcers. The combination of cercariae and pesticides generally posed greater risk to frogs than either factor alone by decreasing survival or growth or increasing time to metamorphosis or malformations. The exception was that lone exposure to chlorpyrifos had higher mortality without than with cercariae. Consistent with mathematical models that suggest that stress should increase the impact of generalist parasites, the weight of the evidence from the field and laboratory suggests that ecologically relevant concentrations of agrochemicals generally increase the threat that trematodes pose to amphibians, highlighting the importance of elucidating interactions between anthropogenic activities and infectious disease in taxa of conservation concern.

  19. Combined Effects of Pesticides and Trematode Infections on Hourglass Tree Frog Polypedates cruciger

    Science.gov (United States)

    Jayawardena, Uthpala A.; Rohr, Jason R.; Navaratne, Ayanthi N.; Amerasinghe, Priyanie H.; Rajakaruna, Rupika S.

    2016-01-01

    The impact of widespread and common environmental factors, such as chemical contaminants, on infectious disease risk in amphibians is particularly important because both chemical contaminants and infectious disease have been implicated in worldwide amphibian declines. Here we report on the lone and combined effects of exposure to parasitic cercariae (larval stage) of the digenetic trematode, Acanthostomum burminis, and four commonly used pesticides (insecticides: chlorpyrifos, dimethoate; herbicides: glyphosate, propanil) at ecologically relevant concentrations on the survival, growth, and development of the common hourglass tree frog, Polypedates cruciger Blyth 1852. There was no evidence of any pesticide-induced mortality on cercariae because all the cercariae successfully penetrated each tadpole host regardless of pesticide treatment. In isolation, both cercarial and pesticide exposure significantly decreased frog survival, development, and growth, and increased developmental malformations, such as scoliosis, kyphosis, and also edema and skin ulcers. The combination of cercariae and pesticides generally posed greater risk to frogs than either factor alone by decreasing survival or growth or increasing time to metamorphosis or malformations. The exception was that lone exposure to chlorpyrifos had higher mortality without than with cercariae. Consistent with mathematical models that suggest that stress should increase the impact of generalist parasites, the weight of the evidence from the field and laboratory suggests that ecologically relevant concentrations of agrochemicals generally increase the threat that trematodes pose to amphibians, highlighting the importance of elucidating interactions between anthropogenic activities and infectious disease in taxa of conservation concern. PMID:26911919

  20. Combined Effects of Pesticides and Trematode Infections on Hourglass Tree Frog Polypedates cruciger.

    Science.gov (United States)

    Jayawardena, Uthpala A; Rohr, Jason R; Navaratne, Ayanthi N; Amerasinghe, Priyanie H; Rajakaruna, Rupika S

    2016-03-01

    The impact of widespread and common environmental factors, such as chemical contaminants, on infectious disease risk in amphibians is particularly important because both chemical contaminants and infectious disease have been implicated in worldwide amphibian declines. Here we report on the lone and combined effects of exposure to parasitic cercariae (larval stage) of the digenetic trematode, Acanthostomum burminis, and four commonly used pesticides (insecticides: chlorpyrifos, dimethoate; herbicides: glyphosate, propanil) at ecologically relevant concentrations on the survival, growth, and development of the common hourglass tree frog, Polypedates cruciger Blyth 1852. There was no evidence of any pesticide-induced mortality on cercariae because all the cercariae successfully penetrated each tadpole host regardless of pesticide treatment. In isolation, both cercarial and pesticide exposure significantly decreased frog survival, development, and growth, and increased developmental malformations, such as scoliosis, kyphosis, and also edema and skin ulcers. The combination of cercariae and pesticides generally posed greater risk to frogs than either factor alone by decreasing survival or growth or increasing time to metamorphosis or malformations. The exception was that lone exposure to chlorpyrifos had higher mortality without than with cercariae. Consistent with mathematical models that suggest that stress should increase the impact of generalist parasites, the weight of the evidence from the field and laboratory suggests that ecologically relevant concentrations of agrochemicals generally increase the threat that trematodes pose to amphibians, highlighting the importance of elucidating interactions between anthropogenic activities and infectious disease in taxa of conservation concern. PMID:26911919

  1. Non-equilibrium plasma prevention of Schistosoma japonicum transmission

    Science.gov (United States)

    Wang, Xing-Quan; Wang, Feng-Peng; Chen, Wei; Huang, Jun; Bazaka, Kateryna; Ostrikov, Kostya (Ken)

    2016-10-01

    Schistosoma japonicum is a widespread human and animal parasite that causes intestinal and hepatosplenic schistosomiasis linked to colon, liver and bladder cancers, and anemia. Estimated 230 million people are currently infected with Schistosoma spp, with 779 million people at risk of contracting the parasite. Infection occurs when a host comes into contact with cercariae, a planktonic larval stage of the parasite, and can be prevented by inactivating the larvae, commonly by chemical treatment. We investigated the use of physical non-equilibrium plasma generated at atmospheric pressure using custom-made dielectric barrier discharge reactor to kill S. japonicum cercariae. Survival rate decreased with treatment time and applied power. Plasmas generated in O2 and air gas discharges were more effective in killing S. japonicum cercariae than that generated in He, which is directly related to the mechanism by which cercariae are inactivated. Reactive oxygen species, such as O atoms, abundant in O2 plasma and NO in air plasma play a major role in killing of S. japonicum cercariae via oxidation mechanisms. Similar level of efficacy is also shown for a gliding arc discharge plasma jet generated in ambient air, a system that may be more appropriate for scale-up and integration into existing water treatment processes.

  2. The Irradiation Effect Against To The Infectivity Of Metacercaria Of Fasciola Gigantica On Goat

    International Nuclear Information System (INIS)

    An experiment was carried out to study the effect of irradiation against to the infectivity of F.gigantica by using observation the exchange of goat bodies condition. Four groups of experiment animals were inoculated by irradiated meta cercaria of F. gigantica at a doses of 0, 45, 55 and 65Gy, and the other one is the negative control. Each experiment animal received 350 lives meta cercaria. The infectivity of irradiated meta cercaria in goat has been followed in the development of body weight, blood value described as the number of red blood cells (RBC), level of haemoglobin (Hb), percentages of packed cell volume (PCV), eosinofil and the last is pathology anatomic inspection. The results obtained showed that 45 Gy is the optimal dose of irradiation for decreasing infectivity of metacercariae of F.gigantica which have the ability to stimulate the good immune response in the goat

  3. Types of trematodes infecting freshwater snails found in irrigation canals in the East Nile locality, Khartoum, Sudan

    DEFF Research Database (Denmark)

    Mohammed, Nidal A. I.; Madsen, Henry; Ahmed, Abdel Aziz A. R. M.

    2016-01-01

    Background: The planorbid freshwater snails of the two genera, Biomphalaria and Bulinus -have been vigorously studied due to the role they play as intermediate hosts of schistosomiasis. In Sudan specifically, most studies have focused on the chemical and ecological control of the two genera...... snails and one Cleopatra bulimoides snail. Twenty different morphotypes of cercariae were recorded, seven of which appeared not to conform to previously described cercariae from Africa. Xiphidiocercariae type 1 was the most common type of cercariae recovered, accounting for 44.3 % of all infections...... intermediate hosts as the schistosomes. Further studies should be conducted to determine whether some of these trematodes could be manipulated for the biological control of schistosomiasis....

  4. Behavior in Mus musculus of Schistosoma mansoni from mollusks treated with hydrocortisone Comportamento em Mus musculus do Schistosoma mansoni oriundo de moluscos tratados com hidrocortisona

    Directory of Open Access Journals (Sweden)

    Deborah Regina Serrano

    2005-10-01

    Full Text Available 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.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.

  5. In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS

    Directory of Open Access Journals (Sweden)

    Kumari Sunita

    2013-09-01

    Full Text Available SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L. Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae.

  6. Fascioliasis Control: In Vivo and In Vitro Phytotherapy of Vector Snail to Kill Fasciola Larva

    Directory of Open Access Journals (Sweden)

    Kumari Sunita

    2011-01-01

    Full Text Available Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, umbelliferone, azadirachtin, and allicin against larva of Fasciola in infected snail Lymnaea acuminata were tested. Mortality of larvae were observed at 2 h, 4 h, 6 h, and 8 h, of treatment. In in vivo treatment, azadirachtin caused highest mortality in redia and cercaria larva (8 h, LC50 0.11, and 0.05 mg/L whereas in in vitro condition allicin was highly toxic against redia and cercaria (8 h, LC50 0.01, and 0.009 mg/L. Toxicity of citral was lowest against redia and cercaria larva.

  7. Digenetic larvae in Schistosome snails from El Fayoum, Egypt with detection of Schistosoma mansoni in the snail by PCR.

    Science.gov (United States)

    Aboelhadid, Shawky M; Thabet, Marwa; El-Basel, Dayhoum; Taha, Ragaa

    2016-09-01

    The present study aims to detect the digenetic larvae infections in Bulinus truncatus and Biomphalaria alexandrina snails and also PCR detection of Schistosoma mansoni infection. The snails were collected from different branches of Yousef canal and their derivatives in El Fayoum Governorate. The snails were investigated for infection through induction of cercarial shedding by exposure to light and crushing of the snails. The shed cercariae were S. mansoni, Pharyngeate longifurcate type I and Pharyngeate longifurcate type II from B. alexandrina, while that found in B. truncatus were Schitosoma haematobium and Xiphidiocercaria species cercariae. The seasonal prevalence of infection was discussed. Polymerase chain reaction was used for the detection of S. mansoni in the DNA from field collected infected and non infected snails. The results of PCR showed that the pool of B. alexandrina snails which shed S. mansoni cercariae in the laboratory, gave positive reaction in the samples. Pooled samples of field collected B. alexandrina that showed negative microscopic shedding of cercariae gave negative and positive PCR in a consecutive manner. Accordingly, a latent infection in the snail (negative microscopic) could be detected by using PCR. PMID:27605774

  8. Plagiorchis elegans (Digenea: Plagiorchiidae) infections in Stagnicola elodes (Pulmonata: Lymnaeidae): host susceptibility, growth, reproduction, mortality, and cercarial production.

    Science.gov (United States)

    Zakikhani, M; Rau, M E

    1999-06-01

    Eggs of Plagiorchis elegans were readily ingested by Stagnicola elodes of all ages, but were more infective to immature than mature snails. Infection enhanced the growth of the host in a dose-dependent manner. The number of cercariae released by immature snails increased with the age of the snail host; mature snails yielded fewer cercariae. Heavily infected snails tended to die prematurely, thereby reducing their total production of cercariae to levels below those of more lightly infected individuals. Even light infections castrated the snail host. Snails that acquired the infection as juveniles never produced eggs. Actively reproducing snails ceased egg laying within days of infection and never recovered. All parasite effects on the growth and reproduction of the snail host first manifested themselves during the early stages of infection, long before the development of daughter sporocysts and cercariae, and are therefore attributable to the effects of mother sporocysts. The study provides insight into how this natural enemy of mosquito larvae may be established in natural snail populations by means of strategically timed introductions of parasite eggs, with a goal of maximizing cercarial production for the biological control of sympatric mosquito larvae. PMID:10386437

  9. Redescription and life cycle of the monorchiid Postmonorcheides maclovini Szidat, 1950 (Digenea) from the Southwestern Atlantic Ocean: Morphological and molecular data.

    Science.gov (United States)

    Bagnato, Estefanía; Gilardoni, Carmen; Pina, Susana; Rodrigues, Pedro; Cremonte, Florencia

    2016-02-01

    The adult monorchiid, Postmonorcheides maclovini Szidat, 1950, digenean parasite of the Patagonian blennie Eleginops maclovinus (Cuvier) (Eleginopidae) from Puerto Deseado (47° 45' S, 65° 55' W), Argentina, was characterized and its life cycle elucidated. P. maclovinus is the only species of the genus Postmonorcheides, proposed by Szidat (1950) from Tierra del Fuego province (~54° S), Argentina. This digenean uses the Patagonian blennie as definitive host, and the intertidal bivalve Lasaea adansoni (Gmelin) (Lasaeidae) as both first and second intermediate hosts (metacercariae encyst inside sporocysts), being the first record of this clam as intermediate host of trematode parasites. The cercaria may, in addition to encysting in the sporocyst, emerge and presumably infect other intermediate hosts. This is the second report of a monorchiid species with metacercariae encysting inside the sporocyst. Adults were found parasitizing the fish stomach, pyloric caeca and intestine with a prevalence of 100%; sporocysts with cercariae and/or metacercariae were found parasitizing the gonad of the bivalve with a prevalence of 2.78%. The cercariae possess a well-developed tail and eye-spots are absent. The ITS1 sequence from the adult digeneans found in the Patagonian blennie, identified as P. maclovini, was found to be identical to the ITS1 sequences obtained both from sporocysts containing cercariae and encysted metacercariae found in L. adansoni. PMID:26423199

  10. Life-cycle stages of a Posthodiplostomum species (Digenea: Diplostomidae) from Patagonia, Argentina.

    Science.gov (United States)

    Ritossa, Luciano; Flores, Verónica; Viozzi, Gustavo

    2013-10-01

    In Patagonia, populations of the galaxiid fish Galaxias maculatus are parasitized by metacercariae of a species of Posthodiplostomum (Digenea: Diplostomidae). The aim of this work was to describe larval and adult stages of this species in experimental and natural hosts from an Andean Patagonian lake. Specimens of G. maculatus and the pulmonate snail, Anisancylus obliquus, were collected in Patagua Lake. The snails were isolated in individual containers to observe emergence of cercariae, dissected, and examined under a stereoscopic microscope to record sporocysts and cercariae. Fish were examined to obtain metacercariae, and uninfected fish from Gutiérrez Lake were exposed to cercariae from A. obliquus to obtain experimental metacercariae. Chicks and mice were infected with metacercariae from naturally infected G. maculatus to obtain experimental adults. Specimens recovered belong to Posthodiplostomum sp. on the basis of morphological features. This is the first description of sporocysts, cercariae, metacercariae, and adults stages of a Posthodiplostomum species in Patagonia, including data about its natural intermediate hosts. PMID:23628085

  11. Cercarial Chaetotaxy and Sex Differentiation of Schistosoma mansoni Deriving from Humans and Nectomys squamipes (Muridae: Sigmondontinae in Brazil

    Directory of Open Access Journals (Sweden)

    Nilcéa Freire

    2002-01-01

    Full Text Available A comparative study was made between sympatric isolates of Schistosoma mansoni: one from a wild rodent (R Nectomys squamipes and another one from humans (H isolated from a low endemic schistosomiasis transmission area in Brazil. Our purpose was to detect differences between them concerning chaetotaxy (number and pattern of distribution of the argentophilic papillae of the cercariae by means of silver impregnation. No significant difference (x > 0.05 between isolates was noted. Nevertheless, a significant difference (x < 0.05 was observed in the cercarial index (ratio of the distance between the first and the second preacetabular papillae and the distance between the first and the second dorsal preacetabular papillae of male and female cercariae in both isolates. Males presented a greater cercarial index than females. By means of multivariate analysis, male cercariae were distinguished from female cercariae through the following characteristics: average number of dorsal papillae on the right quadrant, average number of ventral middle papillae on the right quadrant (H isolate and average number of dorsal middle papillae on the left quadrant (R isolate. The results suggest that R and H isolates belong to the same population that could complete its life cycle in rodent-snail-rodent fashion.

  12. Relationship between snail population density and infection status of snails and fish with zoonotic trematodes in Vietnamese carp nurseries

    DEFF Research Database (Denmark)

    Clausen, Jesper Hedegaard; Madsen, Henry; Murrell, Kenneth Darwin;

    2012-01-01

    Fish-borne zoonotic trematodes (FZT) are a food safety and health concern in Vietnam. Humans and other final hosts acquire these parasites from eating raw or under-cooked fish with FZT metacercariae. Fish raised in ponds are exposed to cercariae shed by snail hosts that are common in fish farm...... to juvenile fish raised in carp nurseries....

  13. Preliminary study on immunotoxin for the prevention of Schistosomiasis japonica

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@To investigate the effects of immunotoxin (bio-missile) on the prevention of schistosomiasis. The monoclonal antibody NP11-4, located in out-layer membrane of adult worm, membrane of cercariae, membrane of schistosomula, shell of egg and membrane of miracidium in egg, was combined with artesunate (produced by Guilin Pharmaceutical Factory of China) by chemical method to fabricate immunotoxin.

  14. Hsp70 May Be a Molecular Regulator of Schistosome Host Invasion.

    Science.gov (United States)

    Ishida, Kenji; Jolly, Emmitt R

    2016-09-01

    Schistosomiasis is a debilitating disease that affects over 240 million people worldwide and is considered the most important neglected tropical disease following malaria. Free-swimming freshwater cercariae, one of the six morphologically distinct schistosome life stages, infect humans by directly penetrating through the skin. Cercariae identify and seek the host by sensing chemicals released from human skin. When they reach the host, they burrow into the skin with the help of proteases and other contents released from their acetabular glands and transform into schistosomula, the subsequent larval worm stage upon skin infection. Relative to host invasion, studies have primarily focused on the nature of the acetabular gland secretions, immune response of the host upon exposure to cercariae, and cercaria-schistosomulum transformation methods. However, the molecular signaling pathways involved from host-seeking through the decision to penetrate skin are not well understood. We recently observed that heat shock factor 1 (Hsf1) is localized to the acetabular glands of infectious schistosome cercariae, prompting us to investigate a potential role for heat shock proteins (HSPs) in cercarial invasion. In this study, we report that cercarial invasion behavior, similar to the behavior of cercariae exposed to human skin lipid, is regulated through an Hsp70-dependent process, which we show by using chemical agents that target Hsp70. The observation that biologically active protein activity modulators can elicit a direct and clear behavioral change in parasitic schistosome larvae is itself interesting and has not been previously observed. This finding suggests a novel role for Hsp70 to act as a switch in the cercaria-schistosomulum transformation, and it allows us to begin elucidating the pathways associated with cercarial host invasion. In addition, because the Hsp70 protein and its structure/function is highly conserved, the model that Hsp70 acts as a behavior transitional

  15. ANTHELMINTIC ACTIVITY OF CHLOROPHYLLIN AGAINST DIFFERENT LARVAL STAGES OF Fasciola gigantica

    Science.gov (United States)

    SINGH, Divya Jyoti; SINGH, Dinesh Kumar

    2016-01-01

    Fasciolosis is a food borne zoonosis, caused by the digenetic trematode Fasciola. Freshwater lymnaeid snails are the intermediate host of the trematodes. Chlorophyllin, a semi-synthetic derivative of chlorophyll and its formulations obtained from freeze dried cow urine (FCU) had their toxicity tested against redia and cercaria larvae of F. gigantica. The larvicidal activity of chlorophyllin and its formulations were found to depend on both, time and concentration used against the larvae. Toxicity of chlorophyllin + FCU (1:1 ratio) in sunlight against redia larva (8 h LC50: 0.03 mg/mL) was more pronounced than using just chlorophyllin (8 h LC50: 0.06 mg/mL). Toxicity of chlorophyllin + FCU in sunlight against redia (8 h LC50: 0.03 mg/mL) was higher than against cercaria (8 h LC50: 0.06 mg/mL). The larvicidal activity of chlorophyllin in sunlight (redia/cercaria larvae: 8 h LC50: 0.06 mg/mL) was more pronounced than under laboratory conditions (redia: 8 h LC50: 22.21 mg/mL/, cercaria 8 h LC50: 96.21 mg/mL). Toxicity of FCU against both larvae was lower than that of chlorophyllin and chlorophyllin + FCU. Chlorophyllin and its formulations + FCU were 357.4 to 1603.5 times more effective against redia/cercaria larvae in sunlight than under laboratory conditions. The present study has shown that chlorophyllin formulations may be used as potent larvicides against fasciolosis. PMID:27253741

  16. Epidemiological situation and molecular identification of cercarial stage in freshwater snails in Chao-Phraya Basin, Central Thailand

    Institute of Scientific and Technical Information of China (English)

    Sothorn Anucherngchai; Thanawan Tejangkura; Thapana Chontananarth

    2016-01-01

    Objective: To investigate the prevalence of cercarial trematode infection in snails and to examine the reconstruction of the phylogenetic relationship to explain the molecular system of cercarial stage trematodes to estimate the infection rate of in the definite host from the Chao-Phraya Basin. Methods: The snails were collected from 10 provinces of the Chao-Phraya Basin, Thailand by stratified sampling method. The snails were examined for cercarial infection by the crushing method. All DNA specimens were amplified with internal transcribed spacer 3 (ITS3) and ITS4 primer based on PCR technique. The sequence data were aligned and used to reconstruct the phylogenetic tree by unweighted pair-group method with arithmetic means with 10 000 bootstraps. Results: The overall rate of cercarial infection was found to be 5.90%(122/2 067). Snails in the family Thiaridae were found to be in the highest prevalence followed by Lym-naeidae, Bithyniidae, Planorbidae, Viviparidae, and Ampullariidae, respectively, while the Buccinidae family (Clea helena) did not reveal any infections. The frequently found species of cercariae were parapleurolophocercous cercariae, cercariae and megarulous cercariae. The monophyletic tree separated the snails into five groups comprised of Heterophyidae, Strigeidae, Lecithodendriidae, Philophthalmidae and Echinostomatidae using the sequence of Angiostrongylus cantonensis as an out-group. Conclusions: This study was the first to report on cercarial infection in the Chao-Phraya Basin, Thailand. This revealed that a high variety of freshwater snails were infected by cercariae stage trematodes with a high prevalence. The sequence data of ITS2 can be used to investigate the phylogenetic relationships of trematodes at the family level and in each clade of different families separated by the definitive hosts.

  17. Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe.

    Science.gov (United States)

    Pfukenyi, D M; Mukaratirwa, S; Willingham, A L; Monrad, J

    2006-09-01

    During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16264 (5418 calves, 5461 weaners and 5385 adults) faecal samples were collected during the entire period of study and 734 (4.5%) were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P Nymphaea caerulea and Typha species. Overall, 2.5% of B. globosus were shedding Schistosoma cercariae. In the highveld, 2.8% of B. globosus were infected with schistosome cercariae and 1.5% in the lowveld, with the figures at individual sites ranging from 0-18.8% in the highveld and from 0-4.5% in the lowveld. The cercariae recorded here were a mixture of S. mattheei and S. haematobium since they share the same intermediate host. The transmission of Schistosoma cercariae exhibited a marked seasonal pattern, being more intensive during the hot, dry season (September/November). PMID:17058440

  18. Viabilidade de miracídios de Schistosoma mansoni, obtidos de fezes e de granulomas hepáticos de camundongos experimentalmente infectados com a linhagem BH Viability of Schislosoma mansoni miracidia obtained from feces and liver granuloma of experimental mice infected with the BH strain

    Directory of Open Access Journals (Sweden)

    Eliana Maria Zanotti-Magalhães

    1988-12-01

    Full Text Available Estudou-se comparativamente a viabilidade, em moluscos hospedeiros, de miracídios de Schistosoma mansoni de duas origens: de ovos eliminados com as fezes e de granulomas hepáticos. Procurou-se saber se havia efeito da origem sobre o número total de cercárias obtidas e sobre o período de eliminação de cercárias. Foram também verificados o período pré-patente da infecção dos moluscos, a sobrevivência do caramujo após a infecção e o sexo das cercárias eliminadas. Concluiu-se que: a o período pré-patente foi maior nos moluscos infectados por miracídios provenientes de granulomas hepáticos; b a sobrevivência dos moluscos após a infecção foi maior naqueles infectados por miracídios provenientes de granulomas hepáticos; c o número de cercadas eliminadas por molusco infectado com miracídios provenientes de granulomas hepáticos foi três vezes maior que o número de cercárias eliminadas por moluscos infectados com miracídios provenientes de ovos eliminados com as fezes.The viability of Schistosoma mansoni miracidia in host molluscs, obtained from two origins is examined: from eggs eliminated with feces of the definitive hosts and liver granuloma eggs. The effect of the origin of the miracidia on the number of cercariae and on the time of cercariae elimination was investigated. The prepatent period of cercariae elimination, snail survival after infection and the sex of the eliminated cercariae were also observed. The following results were obtained: a snails infected with miracidia from liver granuloma eggs took longer to begin to eliminate cercariae; b snail survival after infection was longer in the group infected with miracidia from liver granuloma eggs; c the total number of cercariae produced by the snail group infected with miracidia from liver granuloma eggs was three times that of the group infected with miracidia from eggs eliminated with feces.

  19. [Epidemiological investigation on the intermediate hosts of Paragonimus in Ninghai County of Zhejiang Province].

    Science.gov (United States)

    Liu, Jian-Fa; Wu, Yan; Tang, Zhi-Yuan; Meng, Dan; Yang, Shu-Juan; Jiang, Wen-Wen

    2009-08-01

    Freshwater crabs and snails were collected from Ninghai County in Zhejiang Province, and examined respectively for Paragonimus metacercariae and cercariae. Among 97 freshwater crabs found, the prevalence was 11.3% (11/97) with a mean intensity of 1 metacercariae per crab. It was 10.2% (5/49) and 20.2% (4/20) in the groups weighted 5-15 g and 15-25 g respectively, with an average intensity of 1, and no metacercariae were found in weight group of 25-35 g. Two positive crabs were found from 20 crabs with a low weight (< 5 g). Male to female crabs ratio was 2.5:1, and there was no significant difference in prevalence between males [12.7%(7/55)] and females [9.1% (2/22)]. No cercariae or metacercariae were found in 200 snails (Semisulcospira libertino).

  20. Cercarial emergence pattern of Schistosoma haematobium from Libreville, Gabon.

    Science.gov (United States)

    Mintsa-Nguéma, Rodrigue; Moné, Hélène; Ibikounlé, Moudachirou; Mengué-Ngou-Milama, Krystina; Kombila, Maryvonne; Mouahid, Gabriel

    2014-01-01

    Although schistosomiasis has been a public health issue in Gabon for nearly a century, little is known about its current transmission dynamics. We analyzed the chronobiology of 137 cercarial emission profiles of Schistosoma haematobium from Libreville, the capital of Gabon, located in an open area for schistosomiasis. We found that 88% of the cercariae were shed between 11 a.m. and 3 p.m. and that the average pattern was of circadian type, with the average peak at 1 p.m., and representing 27% of the total number of cercariae of the day. The rhythms of emergence may be associated with environmental pressures on the parasite, especially those related to their definitive hosts.

  1. Differences in the compatibility of infection between the liver flukes Fascioloides magna and Fasciola hepatica in a Colombian population of the snail Galba sp.

    Science.gov (United States)

    Dreyfuss, G; Correa, A C; Djuikwo-Teukeng, F F; Novobilský, A; Höglund, J; Pankrác, J; Kašný, M; Vignoles, P; Hurtrez-Boussès, S; Pointier, J P; Rondelaud, D

    2015-11-01

    Experimental infections of Galba sp. (origin, Colombia) with allopatric isolates of Fasciola hepatica from France or Fascioloides magna from the Czech Republic were carried out during five successive snail generations to determine if this lymnaeid might sustain complete larval development of either parasite. In snails exposed to F. hepatica, 7 of 400 snails harboured several rediae and only two snails contained a small number of free cercariae on day 50 post-exposure. In contrast, the intensity of F. magna infection in Galba sp. progressively increased from the F1 to F5 generations. Spontaneous cercarial shedding of F. magna occurred in 7 of 100 Galba sp. belonging to the F5 generation and the number of shed cercariae did not differ significantly from that noted in control Galba truncatula of French origin. Galba sp. from Colombia can be added to the list of potential intermediate hosts for F. magna.

  2. Molecular diversity of avian schistosomes in Danish freshwater snails

    DEFF Research Database (Denmark)

    Christiansen, Anne Ø.; Olsen, Annette; Buchmann, Kurt;

    2016-01-01

    Avian schistosomes are widespread parasites of snails and waterfowl and may cause cercarial dermatitis (swimmer's itch) in humans, a disease that is frequently reported in European countries. These parasites are known to occur in Denmark, but here, we applied a new approach using molecular tools...... to identify the parasites at species level. In order to do that, 499 pulmonate freshwater snails (Radix sp., Lymnaea stagnalis, Stagnicola sp. and Planorbarius corneus) were sampled from 12 lakes, ponds, and marshes in the greater Copenhagen area. Avian schistosome cercariae were identified by microscopy...... shed different species of Trichobilharzia cercariae: Trichobilharzia szidati was isolated from L. stagnalis, Trichobilharzia franki from Radix auricularia and Trichobilharzia regenti from Radix peregra. In the light of the public health risk represented by bird schistosomes, these findings...

  3. Histological and histomorphometric evaluation of the retina of mice infected with Schistosoma mansoni in its hepatosplenic form Avaliação histológica e histomorfométrica da retina de camundongos infectados pelo Schistosoma mansoni na forma hepatoesplênica

    OpenAIRE

    Maria Cecília de Aguiar Remígio; Carlos Teixeira Brandt; Nicodemos Teles de Pontes Filho; Monica Camelo Pessoa de Azevedo Albuquerque

    2009-01-01

    PURPOSE: To evaluate retinal manifestations of Schistosomiasis mansoni in its hepatosplenic form in mice. METHODS: It was performed a study with two groups of mice; one of them was infected with 40 cercariae of Schistosoma mansoni. After 120 days of the infection, the eyes underwent a retinal microscopy study. The histology findings were reported. Histomorphometric analysis was also performed, including: thickness measurement of the retinal layer and the number of the ganglion layer cells. RE...

  4. Variant abiotic factors and the infection of Fasciola gigantica larval stages in vector snail Indoplanorbis exustus

    OpenAIRE

    Neha Singh; Pradeep Kumar; Dinesh Kumar Singh

    2012-01-01

    The aquatic environment has numerous physical and chemical parameters that may influence the physiology and maturation rate of parasite found inside the vector snail. It may be possible that abiotic factors (temperature, pH, CO2, O2 and conductivity) and higher population density of snails could promote the transmission of parasite and raise their local abundance. In the present paper, we examined that how these environmental factors affect the transmission of cercaria throughout the year 200...

  5. Cockle infection by Himasthla quissetensis - II. The theoretical effects of climate change

    Science.gov (United States)

    de Montaudouin, Xavier; Blanchet, Hugues; Desclaux-Marchand, Céline; Bazairi, Hocein; Alfeddy, Nazik; Bachelet, Guy

    2016-07-01

    Numerous marine populations experience parasite pressure. This is the case of the cockles Cerastoderma edule which are often highly infected by trematode macroparasites. These parasites display a complex life cycle, with a succession of free-living and parasitic stages. Climate, and in particular temperature, is an important modulator of the transmission dynamics of parasites. Consequently, global change is thought to have implications for the epidemiology of infectious diseases. Using Himasthla quissetensis, a dominant parasite of cockles as 2nd intermediate host in Arcachon Bay (France), we used mathematical models of parasite emergence (cercariae) and parasite infection (metacercariae) in cockles as a function of water temperature, in order to study different scenarios of temperature increases. Globally, with a + 0.5 °C to + 6.0 °C simulation, cumulated emergence of cercariae and accumulation of metacercariae tended to decrease or stagnate, respectively. This is the consequence of a trade-off between sooner (spring) and later (autumn) cercariae emergence/infestation on one hand, and a longer inhibition period of cercariae emergence/infestation during the hottest days in summer. Using sea water temperature in Oualidia (Morocco) where mean annual sea temperature is 3 °C higher than in Arcachon Bay, our model predicted infestation all year long (no seasonality). The model gave a correct estimation of the total number of parasites that was expected in cockles. Conversely, observed infestation in Oualidia followed a seasonal pattern like in Arcachon Bay. These results suggest that, if temperature is a strong driver of parasite transmission, extrapolation in the framework of climate change should be performed with caution.

  6. A Ribeiroia spp. (Class: Trematoda) - Specific PCR-based diagnostic

    Science.gov (United States)

    Reinitz, D.M.; Yoshino, T.P.; Cole, R.A.

    2007-01-01

    Increased reporting of amphibian malformations in North America has been noted with concern in light of reports that amphibian numbers and species are declining worldwide. Ribeiroia ondatrae has been shown to cause a variety of types of malformations in amphibians. However, little is known about the prevalence of R. ondatrae in North America. To aid in conducting field studies of Ribeiroia spp., we have developed a polymerase chain reaction (PCR)-based diagnostic. Herein, we describe the development of an accurate, rapid, simple, and cost-effective diagnostic for detection of Ribeiroia spp. infection in snails (Planorbella trivolvis). Candidate oligonucleotide primers for PCR were designed via DNA sequence analyses of multiple ribosomal internal transcribed spacer-2 regions from Ribeiroia spp. and Echinostoma spp. Comparison of consensus sequences determined from both genera identified areas of sequence potentially unique to Ribeiroia spp. The PCR reliably produced a diagnostic 290-base pair (bp) product in the presence of a wide concentration range of snail or frog DNA. Sensitivity was examined with DNA extracted from single R. ondatrae cercaria. The single-tube PCR could routinely detect less than 1 cercariae equivalent, because DNA isolated from a single cercaria could be diluted at least 1:50 and still yield a positive result via gel electrophoresis. An even more sensitive nested PCR also was developed that routinely detected 100 fg of the 290-bp fragment. The assay did not detect furcocercous cercariae of certain Schistosomatidae, Echinostoma sp., or Sphaeridiotrema globulus nor adults of Clinostomum sp. or Cyathocotyle bushiensis. Field testing of 137 P. trivolvis identified 3 positives with no overt environmental cross-reactivity, and results concurred with microscopic examinations in all cases. ?? American Society of Parasitologists 2007.

  7. Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

    OpenAIRE

    Simões Carla; Neves Renata Heisler; Barros Lucas de Andrade; Brito Patrícia Dias; Cravo Cristiane Oliveira; Moura Egberto Gaspar de; Machado-Silva José Roberto

    2002-01-01

    The effects of a protein-restricted diet (8% protein, 81% carbohydrate and 11% lipids) on Schistosoma mansoni infectivity, fecal egg excretion and intestinal egg distribution in Swiss (SW) mice were studied. Pregnant mice received a deficient diet from the middle of gestation until delivery. Seven-days-old mice were exposed to 50 cercariae (BH strain, Brazil). Offspring mice had a free access to the deficient diet since lactation until adulthood. The controls were fed with a commercial mice d...

  8. Structural changes in the jejunal mucosa of mice infected with Schistosoma mansoni, fed low or high protein diets Alterações estruturais na mucosa jejunal de camundongos infectados com Schistosoma mansoni, alimentados com dietas hipo ou hiperprotéicas

    OpenAIRE

    Janira Lúcia Assumpção Couto; Haroldo da Silva Ferreira; Dinalva Bezerra da Rocha; Maria Eugênia Leite Duarte; Monica Lopes de Assunção; Eridan de Medeiros Coutinho

    2002-01-01

    The effects of high and low-protein diets on the structure of the jejunal mucosa were studied in Schistosoma mansoni infected mice (morphology and histomorphometry). Weaning male albino mice were infected with 80 cercariae, fed with high (20%) or low-protein (5%) diets and compared to uninfected controls under the same conditions. Mice were sacrificed 12 weeks after infection. Animals submitted to a low-protein diet showed lower weight curves, mainly when infected. In the jejunal mucosa, fing...

  9. Structural changes in the jejunal mucosa of mice infected with Schistosoma mansoni, fed low or high protein diets

    OpenAIRE

    Couto Janira Lúcia Assumpção; Ferreira Haroldo da Silva; Rocha Dinalva Bezerra da; Duarte Maria Eugênia Leite; Assunção Monica Lopes; Coutinho Eridan de Medeiros

    2002-01-01

    The effects of high and low-protein diets on the structure of the jejunal mucosa were studied in Schistosoma mansoni infected mice (morphology and histomorphometry). Weaning male albino mice were infected with 80 cercariae, fed with high (20%) or low-protein (5%) diets and compared to uninfected controls under the same conditions. Mice were sacrificed 12 weeks after infection. Animals submitted to a low-protein diet showed lower weight curves, mainly when infected. In the jejunal mucosa, fing...

  10. Schistosoma mansoni Antigens Modulate Experimental Allergic Asthma in a Murine Model: a Major Role for CD4+ CD25+ Foxp3+ T Cells Independent of Interleukin-10▿

    OpenAIRE

    Pacífico, Lucila G. G.; Marinho, Fábio A. V.; Fonseca, Cristina T; Michele M Barsante; Pinho, Vanessa; Sales-Junior, Policarpo A.; Luciana S Cardoso; Araújo, Maria Ilma; Carvalho, Edgar M; Cassali, Geovanni D; Teixeira, Mauro M; Oliveira, Sergio C.

    2008-01-01

    In areas where schistosomiasis is endemic, a negative correlation is observed between atopy and helminth infection, associated with a low prevalence of asthma. We investigated whether Schistosoma mansoni infection or injection of parasite eggs can modulate airway allergic inflammation in mice, examining the mechanisms of such regulation. We infected BALB/c mice with 30 S. mansoni cercariae or intraperitoneally injected 2,500 schistosome eggs, and experimental asthma was induced by ovalbumin (...

  11. Risk profiling of schistosomiasis using remote sensing: approaches, challenges and outlook

    OpenAIRE

    Walz, Yvonne; Wegmann, Martin; Dech, Stefan; Raso, Giovanna; Utzinger, Jürg

    2015-01-01

    Background Schistosomiasis is a water-based disease that affects an estimated 250 million people, mainly in sub-Saharan Africa. The transmission of schistosomiasis is spatially and temporally restricted to freshwater bodies that contain schistosome cercariae released from specific snails that act as intermediate hosts. Our objective was to assess the contribution of remote sensing applications and to identify remaining challenges in its optimal application for schistosomiasis risk profiling i...

  12. In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS

    OpenAIRE

    Kumari Sunita; Pradeep Kumar; Vinay Kumar Singh; Dinesh Kumar Singh

    2013-01-01

    SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary com...

  13. Hepatic regeneration after partial hepatectomy in mice infected with Schistosoma mansoni, at the acute and chronic phases of the disease Regeneração hepática após hepatectomia parcial em camundongos infectados com Schistosoma mansoni, nas fases aguda e crônica da doença

    OpenAIRE

    Costa, G.(INFN Sezione di Milano, Milan, Italy); J.R. Cunha-Melo; AGUIAR B.G.; Gonçalves, S. C.; TOPPA N.H.; P. M. Z. Coelho

    1999-01-01

    Outbred male albino mice normal or infected with 30 cercariae of Schistosoma mansoni (LE strain) were submitted to 65% hepatectomy during the acute (70 days) and chronic phase (160 days) phases of the disease. A group of the infected animals was treated with 400 mg/kg of oxamniquine during the acute phase before hepatectomy. Non-infected, infected and treated but not hepatectomized animals were kept as controls. Hepatic regeneration was evaluated by incorporation of tritiated thymidine, intra...

  14. Biomphalaria straminea (Mollusca: Planorbidae) as an intermediate host of Drepanocephalus spp. (Trematoda: Echinostomatidae) in Brazil: a morphological and molecular study.

    Science.gov (United States)

    Pinto, Hudson A; Griffin, Matt J; Quiniou, Sylvie M; Ware, Cynthia; Melo, Alan L

    2016-01-01

    Species of trematodes belonging to the genus Drepanocephalus are intestinal parasites of piscivorous birds, primarily cormorants (Phalachrocorax spp.), and are widely reported in the Americas. During a 4-year malacological study conducted on an urban lake in Brazil, 27-collar-spined echinostome cercariae were found in 1665/15,459 (10.7 %) specimens of Biomphalaria straminea collected. The cercariae were identified as Drepanocephalus spp. by sequencing the 18S (SSU) rDNA, ITS1/5.8S rDNA/ITS2 (ITS), 28S (LSU) rDNA region, cytochrome oxidase subunit 1 (CO1), and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) markers. In experimental life cycle studies, metacercariae developed in laboratory-reared guppies (Poecilia reticulata); however, attempts to infect birds and rodents were unsuccessful. Two closely related morphotypes of cercariae were characterized. One species, identified by molecular markers as a genetic variant of Drepanocephalus auritus (99.9 % similarity at SSU, ITS, LSU; 97.2 % at CO1; 95.8 % at ND1), differs slightly from an archived North American isolate of this species also sequenced as part of this study. A second species, putatively identified as Drepanocephalus sp., has smaller cercariae and demonstrates significant differences from D. auritus at the CO1 (11.0 %) and ND1 (13.6 %) markers. Aspects related to the morphological taxonomic identification of 27-collar-spined echinostome metacercariae are briefly discussed. This is the first report of the involvement of molluscs of the genus Biomphalaria in the transmission of Drepanocephalus and the first report of D. auritus in South America.

  15. Patterns of parasite transmission in polar seas: Daily rhythms of cercarial emergence from intertidal snails

    Science.gov (United States)

    Prokofiev, Vladimir V.; Galaktionov, Kirill V.; Levakin, Ivan A.

    2016-07-01

    Trematodes are common parasites in intertidal ecosystems. Cercariae, their dispersive larvae, ensure transmission of infection from the first intermediate molluscan host to the second intermediate (invertebrates and fishes) or the final (fishes, marine birds and mammals) host. Trematode transmission in polar seas, while interesting in many respects, is poorly studied. This study aimed to elucidate the patterns of cercarial emergence from intertidal snails at the White Sea and Barents Sea. The study, involving cercariae of 12 species, has provided the most extensive material obtained so far in high latitude seas (66-69° N). The experiments were conducted in situ. Multichannel singular spectral analysis (MSSA) used for processing primary data made it possible to estimate the relative contribution of different oscillations into the analysed time series and to separate the daily component from the other oscillatory components and the noise. Cercarial emergence had pronounced daily rhythms, which did not depend on the daily tidal schedule but were regulated by thermo- and photoperiod. Daily emergence maximums coincided with periods favourable for infecting the second intermediate hosts. Cercarial daily emergence rhythms differed in species using the same molluscan hosts which can be explained by cercarial host searching behaviour. Daily cercarial output (DCO) correlated negatively with larval volume and positively with that of the molluscan host except in cercariae using ambuscade behaviour. In the Barents Sea cercariae emerged from their molluscan hosts at lower temperatures than in the warmer White Sea but the daily emergence period was prolonged. Thus, DCO of related species were similar in these two seas and comparable with DCO values reported for boreal seas. Local temperature adaptations in cercarial emergence suggests that in case of Arctic climate warming trematode transmission in coastal ecosystems is likely to be intensified not because of the increased

  16. Immunolocalization of anti-hsf1 to the acetabular glands of infectious schistosomes suggests a non-transcriptional function for this transcriptional activator.

    Directory of Open Access Journals (Sweden)

    Kenji Ishida

    Full Text Available Schistosomiasis is a chronically debilitating disease caused by parasitic worms of the genus Schistosoma, and it is a global problem affecting over 240 million people. Little is known about the regulatory proteins and mechanisms that control schistosome host invasion, gene expression, and development. Schistosome larvae, cercariae, are transiently free-swimming organisms and infectious to man. Cercariae penetrate human host skin directly using proteases that degrade skin connective tissue. These proteases are secreted from anucleate acetabular glands that contain many proteins, including heat shock proteins. Heat shock transcription factors are strongly conserved activators that play crucial roles in the maintenance of cell homeostasis by transcriptionally regulating heat shock protein expression. In this study, we clone and characterize the schistosome Heat shock factor 1 gene (SmHSF1. We verify its ability to activate transcription using a modified yeast one-hybrid system, and we show that it can bind to the heat shock binding element (HSE consensus DNA sequence. Our quantitative RT-PCR analysis shows that SmHSF1 is expressed throughout several life-cycle stages from sporocyst to adult worm. Interestingly, using immunohistochemistry, a polyclonal antibody raised against an Hsf1-peptide demonstrates a novel localization for this conserved, stress-modulating activator. Our analysis suggests that schistosome Heat shock factor 1 may be localized to the acetabular glands of infective cercariae.

  17. Conservation and developmental expression of ubiquitin isopeptidases in Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Roberta Verciano Pereira

    2014-02-01

    Full Text Available Several genes related to the ubiquitin (Ub-proteasome pathway, including those coding for proteasome subunits and conjugation enzymes, are differentially expressed during the Schistosoma mansoni life cycle. Although deubiquitinating enzymes have been reported to be negative regulators of protein ubiquitination and shown to play an important role in Ub-dependent processes, little is known about their role in S. mansoni . In this study, we analysed the Ub carboxyl-terminal hydrolase (UCHs proteins found in the database of the parasite’s genome. An in silico ana- lysis (GeneDB and MEROPS identified three different UCH family members in the genome, Sm UCH-L3, Sm UCH-L5 and Sm BAP-1 and a phylogenetic analysis confirmed the evolutionary conservation of the proteins. We performed quantitative reverse transcription-polymerase chain reaction and observed a differential expression profile for all of the investigated transcripts between the cercariae and adult worm stages. These results were corroborated by low rates of Z-Arg-Leu-Arg-Gly-Gly-AMC hydrolysis in a crude extract obtained from cercariae in parallel with high Ub conjugate levels in the same extracts. We suggest that the accumulation of ubiquitinated proteins in the cercaria and early schistosomulum stages is related to a decrease in 26S proteasome activity. Taken together, our data suggest that UCH family members contribute to regulating the activity of the Ub-proteasome system during the life cycle of this parasite.

  18. Molecular identification of larval trematode in intermediate hosts from Chiang Mai, Thailand.

    Science.gov (United States)

    Chuboon, Suksan; Wongsawad, Chalobol

    2009-11-01

    Snail and fish intermediate hosts were collected from rice fields in 3 districts; Mueang, Mae Taeng and Mae Rim of Chiang Mai Province during April-July 2008. For identification of larval trematode infection, standard (cracked for snail and enzymatically digested for fish) and molecular methods were performed. The results showed that three types of cercariae were found, pleurolophocercus, cotylocercous, and echinostome among 4 species of snail with a prevalence of 29, 23 and 3% respectively. Melanoides tuberculata snail was the most susceptible host for cercariae infection. Four species of metacercariae, Haplorchis taichui, Stellantchasmus falcatus, Haplorchoides sp and Centrocestus caninus, were found with a prevalence of 67, 25, 60 and 20%, respectively. The Siamese mud carp (Henicorhynchus siamensis) was the most susceptible fish host for H. taichui, and half- beaked fish (Dermogenys pusillus) for S. falcatus metacercariae infection, whereas Haplorchoides sp and C. caninus were concomitantly found in Puntius brevis. HAT-RAPD profile confirmed that pleurolophocercus cercariae found in Melanoides tuberculata from Mae Taeng District belonged to H. taichui and in Tarebia granifera from Mueang District were S. falcatus.

  19. The life cycle of Hexangium sigani Goto & Ozaki, 1929 (Digenea: Microscaphidiidae) from the Red Sea.

    Science.gov (United States)

    Hassanine, R M El-Said; Al-Zahrani, D A; Touliabah, H El-S; Youssef, E M

    2016-09-01

    The microscaphidiid Hexangium sigani Goto & Ozaki, 1929 was found in the intestine of Siganus rivulatus, a siganid fish permanently resident in a lagoon within the mangrove swamps on the Egyptian coast of the Gulf of Aqaba. Intra-molluscan stages of this trematode (mother sporocysts, rediae and cercariae) were found in the gonads and digestive gland of Nassarius pullus (Gastropoda: Nassariidae), a common snail in the same lagoon. Consequently, the life cycle of H. sigani was elucidated under natural conditions: eggs are directly ingested by the snail; mother sporocysts and rediae reach maturity 5-7 and 16-17 weeks post-infection; rediae contain 18-26 developing cercariae; fully developed cercariae are monostome, without penetration glands, emerge from the snail during the night 18-19 weeks post-infection and rapidly encyst on aquatic vegetation (there is no second intermediate host); encysted metacercariae are not progenetic; 2-day-old metacercariae encysted on filamentous algae fed to S. rivulatus developed into fully mature worms 5-6 weeks post-infection. The cycle was completed in about 24 weeks. The intra-molluscan stages are very similar to those of Dictyangium chelydrae Stunkard, 1943, the only described intra-molluscan stages of any microscaphidiid. However, they are also similar to those of the family Mesometridae. The present study of H. sigani describes the first complete microscaphidiid life cycle, and implicitly supports the phylogenetic relationship of this family with the Mesometridae inferred from molecular phylogenetic studies. PMID:26279005

  20. Compatibility of Schistosoma mansoni Cameroon and Biomphalaria pfeifferi Senegal.

    Science.gov (United States)

    Southgate, V R; Tchuenté, L A; Théron, A; Jourdane, J; Ly, A; Moncrieff, C B; Gryseels, B

    2000-11-01

    The vectorial capacity of Biomphalaria pfeifferi from Ndiangue, Senegal, was investigated with an allopatric isolate of Schistosoma mansoni from Nkolbisson, Cameroon. The snail infection rate after exposure to a single miracidium per snail (MD1) was 56. 3 %, and 91.6%, for snails exposed to 5 miracidia per snail (MD5). The minimum pre-patent period was 21 days. The mean total cercarial production for the MDI group was 18,511 cercariae per snail, and 9757 cercariae for the MD5 group. The maximum production of cercariae for 1 day was 4892 observed in a snail from the MDI group at day 43 post-infection. The mean longevity of snails was higher in group MD1 (88 days p.i.) than in group MD5 (65 days p.i.). The chronobiological emergence pattern revealed a circadian rhythm with one shedding peak at mid-day. Comparisons are made with the vectorial capacity of the sympatric combination of B. pfeifferi Senegal/S. mansoni Senegal.

  1. Consequence of temperature changes on cercarial shedding from Galba truncatula infected with Fasciola hepatica or Paramphistomum daubneyi

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    Rondelaud Daniel

    2013-01-01

    Full Text Available Experimental infections of Galba truncatula (two populations with Fasciola hepatica or Paramphistomum daubneyi were carried out to study the effect of water temperature changes (3 h at a mean of 12 °C every week on cercarial shedding during the patent period. The results were compared with those of control snails infected according to the same protocol and always maintained at 20 °C. Compared to controls, a significant increase in the number of cercariae-shedding snails, a significantly longer patent period and significantly greater cercarial production were noted in temperature-challenged snails, regardless of the type of digenean infection. In contrast, the number of incompletely formed metacercariae was significantly higher in temperature-challenged snails than in controls. Incompletely formed metacercariae of F. hepatica consisted of cysts whose colour remained whitish after shedding (25.4% for temperature-challenged snails or whose dome was flattened after encystment (74.6%. Those of P. daubneyi were totally dark brown or blackish after formation. These incomplete metacercariae might originate from young differentiating cercariae within the snail body (F. hepatica or from cercariae which died just after encystment (P. daubneyi. The use of regular temperature changes for snails infected with F. hepatica or P. daubneyi must be monitored carefully during collection of metacercariae to select completely formed cysts for infecting definitive hosts.

  2. Aptitude of Lymnaea palustris and L. stagnalis to Fasciola hepatica larval development through the infection of several successive generations of 4-mm-high snails.

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    Vignoles, P; Rondelaud, D; Dreyfuss, G

    2016-06-01

    Bimiracidial infections of Lymnaea palustris and Lymnaea stagnalis (shell height at exposure, 4 mm) with Fasciola hepatica were carried out during six successive snail generations to determine if prevalence and intensity of snail infection increased over time through descendants issuing from eggs laid by parents already exposed to this digenean. Controls were constituted by a French population of Galba truncatula (a single generation) infected according to the same protocol. In a first experiment performed with the F1 to F5 generations of L. palustris, the prevalence and intensity of F. hepatica infection in snails progressively increased. Immature rediae and a few cercariae-containing rediae of the digenean were observed in L. stagnalis from the F3 generation, but no free cercaria was noted in the bodies of this lymnaeid from the F4 to F6 generations. In another experiment carried out with the F6 generation of L. palustris, the prevalence of F. hepatica infection and the number of shed cercariae were significantly lower in L. palustris than in G. truncatula. This mode of snail infection suggests an explanation for cases of human fasciolosis occurring in central France after the collection of wild watercress from beds where L. palustris was the sole lymnaeid.

  3. Lymnaea glabra: progressive increase in susceptibility to Fasciola hepatica through successive generations of experimentally infected snails.

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    Rondelaud, D; Teukeng, F F Djuikwo; Vignoles, P; Dreyfuss, G

    2015-07-01

    Experimental infections of Lymnaea glabra (two populations) with Fasciola hepatica were carried out during seven successive snail generations, to determine if prevalence and intensity of snail infection increased over time through descendants of snails already infected with F. hepatica. Controls were descendants coming from uninfected parents and infected according to the same protocol. No larval forms were found in the bodies of control snails coming from uninfected parents. In contrast, prevalence and intensity of F. hepatica infection in snails originating from infected parents progressively increased from the F2 or F3 to the F6 generation of L. glabra. In another experiment carried out with the F7 generations of L. glabra and a single generation of Galba truncatula (as controls), the prevalence of F. hepatica infection and the total number of cercariae were lower in L. glabra (without significant differences between both populations). If the number of cercariae shed by infected snails was compared to overall cercarial production noted in snails containing cercariae but dying without emission, the percentage was greater in G. truncatula (69% instead of 52-54% in L. glabra). Even if most characteristics of F. hepatica infection were lower in L. glabra, prevalence and intensity of parasite infection increased with snail generation when tested snails came from infected parents. This mode of snail infection with F. hepatica suggests an explanation for cases of fasciolosis occurring in cattle-breeding farms where paramphistomosis is lacking and G. truncatula is absent.

  4. Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca

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    Molla, Eshetu; Giday, Mirutse; Erko, Berhanu

    2013-01-01

    Objective To assess the molluscicidal and cercariacidal activities of aqueous extracts of Balanites aegyptiaca (B. aegyptiaca) against Ethiopian Biomphalaria pfeifferi (B. pfeifferi), Lymnaea natalensis (L. natalensis) and Schistosoma mansoni (S. mansoni) cercariae. Methods Extracts of seeds, endocarp, mesocarp, and fruit of B. aegyptiaca were tested for their activities against adult B. pfeifferi and L. natalensis. The cercariacidal activity of the seeds of the plant was also evaluated against S. mansoni. Bioassays were carried out following the methods recommended by WHO. Snail mortalities were compared between each plant part and snail species, and LC50 and LC90 values for the plant parts tested were computed. The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B. aegyptiaca seeds. Results For the molluscicidal activities of seeds, endocarp, mesocarp and whole fruit, the LC50 values against B. pfeifferi were 56.32, 77.53, 65.51 and 66.63 mg/L, respectively, while the respective LC90 values were 77.70, 120.04, 89.50 and 97.55 mg/L. Similarly, the LC50 values for the seeds, endocarp, mesocarp and whole fruit against L. natalensis were 80.33, 92.61, 83.52 and 87.84 mg/L, respectively, while the respective LC90 values were 102.30, 138.21, 115.42 and 127.69 mg/L. B. pfeifferi were found to be more susceptible to B. aegyptiaca than L. natalensis. S. mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice. The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract. Conclusions The aqueous extracts of different parts of B. aegyptiaca exhibited reasonable molluscicidal activity against B. pfeifferi and L. natalensis, as well as cercariacidal activity against S. mansoni cercariae. However, comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other

  5. Life cycle of Renylaima capensis, a brachylaimid trematode of shrews and slugs in South Africa: two-host and three-host transmission modalities suggested by epizootiology and DNA sequencing

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    Sirgel Wilhelm F

    2012-08-01

    Full Text Available Abstract Background The life cycle of the brachylaimid trematode species Renylaima capensis, infecting the urinary system of the shrew Myosorex varius (Mammalia: Soricidae: Crocidosoricinae in the Hottentots Holland Nature Reserve, South Africa, has been elucidated by a study of its larval stages, epizootiological data in local snails and mammals during a 34-year period, and its verification with mtDNA sequencing. Methods Parasites obtained from dissected animals were mounted in microscope slides for the parasitological study and measured according to standardized methods. The mitochondrial DNA cox1 gene was sequenced by the dideoxy chain-termination method. Results The slugs Ariostralis nebulosa and Ariopelta capensis (Gastropoda: Arionidae act as specific first and second intermediate hosts, respectively. Branched sporocysts massively develop in A. nebulosa. Intrasporocystic mature cercariae show differentiated gonads, male terminal duct, ventral genital pore, and usually no tail, opposite to Brachylaimidae in which mature cercariae show a germinal primordium and small tail. Unencysted metacercariae, usually brevicaudate, infect the kidney of A. capensis and differ from mature cercariae by only a slightly greater size. The final microhabitats are the kidneys and ureters of the shrews, kidney pelvis and calyces in light infections and also kidney medulla and cortex in heavy infections. Sporocysts, cercariae, metacercariae and adults proved to belong to R. capensis by analysis of a 437-bp-long cox1 fragment, which was identical except for three mutations in metacercariae, of which only one silent. Epizootiological studies showed usual sporocyst infection in A. nebulosa and very rare metacercarial infection in A. capensis, which does not agree with high prevalences and intensities in the shrews. Conclusions The presence of monotesticular adult forms and larval prevalences and intensities observed suggest that R. capensis may use two transmission

  6. Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

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    D.M. Pfukenyi

    2006-09-01

    Full Text Available During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16 264 (5 418 calves, 5 461 weaners and 5 385 adults faecal samples were collected during the entire period of study and 734 (4.5 % were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001, calves compared to adult cattle (P < 0.01 and the wet season compared to the dry season (P < 0.01. Faecal egg output peaked from October/ November to March / April for both years of the study. Bulinus globosus, the snail intermediate host of S. mattheei was recorded from the study sites with the highveld having a significantly higher abundance of the snails than the lowveld (P < 0.01. Monthly densities of B. globosus did not show a clearcut pattern although there were peaks between March / May and September / November. The mean num ber of snails collected was positively correlated with the water plants Nymphaea caerulea and

  7. The neuromuscular system in freshwater furcocercaria from Belarus. II Diplostomidae, Strigeidae, and Cyathocotylidae.

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    Tolstenkov, Oleg O; Akimova, Ludmila N; Terenina, Nadezhda B; Gustafsson, Margaretha K S

    2012-02-01

    The neuromuscular system (NMS) in cercariae of Diplostomum pseudospathaceum, Cotylurus szidati, Australapatemon burti, Holostephanus volgensis, and Paracoenogonimus ovatus was studied with immunocytochemical methods and confocal scanning laser microscopy. The patterns of F-actin in the musculature, 5-HT immunoreactive (-IR), FMRF-amide-IR neuronal elements, and α-tubulin-IR in sensory receptors were investigated. The NMS in the five species studied were compared with each other and with three species of Schistosomatidae studied earlier (Bilharziella polonica, Trichobilharzia szidati, and Trichobilharzia franki). No major structural differences in the musculature, the 5-HT-IR or FMRF-IR neuronal elements were noticed between the cercariae. The minor variations observed in the musculature were related to the size and organization of the muscle fibers. The checked pattern formed by the transverse muscle fibers in the tail stems of D. pseudospathaceum, C. szidati, A. burti, H. volgensis, and P. ovatus was not observed in B. polonica, T. szidati, and T. franki. A trend in the differentiation of the longitudinal muscle fibers in the furca from evenly distributed fibers in H. volgensis and P. ovatus to many bundles in D. pseudospathaceum and two well-organized lateral bundles in C. szidati, A. burti, and Trichobilharzia spp. was observed. The transverse muscle fibers in the furca follow the same trend. The number of 5-HT-IR neurons in the cercarial bodies varied between 10 and 16. In cercariae of H. volgensis and P. ovatus, the central nervous system (CNS) was less centralized compared to the CNS in the other species studied, with only two 5-HT-IR marker neurons in each brain ganglion and the other neurons distributed evenly along the main cords. In the tails of H. volgensis and P. ovatus, many transverse 5-HT-IR comissures were found. In the tails of higher strigeidid cercariae, only a few crosslinks were observed. The number and distribution of sensory receptors on the

  8. Laboratory assessment of the molluscicidal and cercariacidal activities of Balanites aegyptiaca

    Institute of Scientific and Technical Information of China (English)

    Eshetu Molla; Mirutse Giday; Berhanu Erko

    2013-01-01

    Objective: To assess the molluscicidal and cercariacidal activities of aqueous extracts ofBalanites aegyptiaca (B. aegyptiaca) against Ethiopian Biomphalaria pfeifferi (B. pfeifferi), Lymnaea natalensis (L. natalensis) and Schistosoma mansoni (S. mansoni) cercariae. Methods:Extracts of seeds, endocarp, mesocarp, and fruit of B. aegyptiaca were tested for their activities against adult B. pfeifferi and L. natalensis. The cercariacidal activity of the seeds of the plant was also evaluated against S. mansoni. Bioassays were carried out following the methods recommended by WHO. Snail mortalities were compared between each plant part and snail species, and LC50 and LC90 values for the plant parts tested were computed. The cercariacidal activity of the plant was assessed by exposing the mice to the cercariae pre-exposed to aqueous extract of B. aegyptiaca seeds. Results:For the molluscicidal activities of seeds, endocarp, mesocarp and whole fruit, the LC50 values against B. pfeifferi were 56.32, 77.53, 65.51 and 66.63 mg/L, respectively, while the respective LC90 values were 77.70, 120.04, 89.50 and 97.55 mg/L. Similarly, the LC50 values for the seeds, endocarp, mesocarp and whole fruit against L. natalensis were 80.33, 92.61, 83.52 and 87.84 mg/L, respectively, while the respective LC90 values were 102.30, 138.21, 115.42 and 127.69 mg/L. B. pfeifferi were found to be more susceptible to B. aegyptiaca than L. natalensis. S. mansoni cercariae exposed to 15 mg/L of extract of seeds were incapable of infecting mice. The mean egg load of tissue was reduced in mice infected with the cercariae exposed to 5 and 10 mg/L of the extract. Conclusions:The aqueous extracts of different parts of B. aegyptiaca exhibited reasonable molluscicidal activity against B. pfeifferi and L. natalensis, as well as cercariacidal activity against S. mansoni cercariae. However, comprehensive laboratory evaluation is recommended prior to field tests of the plant parts since their impact on other

  9. LARVAS DE DIGENEA EN Melanoides tuberculata (GASTROPODA: THIARIDAE EN MEDELLÍN, COLOMBIA Larval stages of digenea from Melanoides tuberculata (Gastropoda: Thiaridae in Medellín, Colombia

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    DANIELA VERGARA

    Full Text Available Se describen las larvas de digeneos que se obtuvieron en Melanoides tuberculata (Gastropoda: Thiaridae, molusco dulceacuícola del que se colectaron 125 especímenes en el lago del Jardín Botánico Joaquín Antonio Uribe de Medellín. En el laboratorio se individualizaron y se estimuló la emisión cercariana con una fuente luminosa. El 9,6 % de los caracoles emitió cercarias. Los moluscos emisores se sacrificaron para obtener los demás estadios larvarios. Las larvas se montaron al microscopio, se midieron y luego se dibujaron. Los caracteres morfológicos permitieron establecer la presencia de Centrocestus formosanus (Heterophyidae y de dos Philophthalmidae. Uno de estos es primer registro para Colombia. Se confirma la sensibilidad de M. tuberculata a infecciones por digeneos, así como la especificidad de los filoftálmidos por moluscos hospedadores de la superfamilia Cerithioidea.The larvae of two trematodes found in the freshwater mollusk Melanoides tuberculata (Gastropoda: Thiaridae are described. 125 snails from the Medellin’s Botanical Garden Joaquín Antonio Uribe were collected. In the laboratory, each individual was placed alone and stimulated with light in order to have cercaria emission. 9.6% of the snails released cercariae. These were separated in three morphologies. From each one, 15 individuals were measured and drawn. Photographs were taken. Based on their morphological characteritics the presence of Centrocestus formosanus (Heterophyidae was determined. The other two morphologies were classified in the family Philophthalmidae. One of them constitutes the first register for Colombia. The sensibility of M. tuberculata to infections by digeneans, and the specificity of the family Philophthalmidae to mollusk hosts of the superfamily Cerithioidea are confirmed

  10. [Demography and the phenomenon of intraspecific competition of Gymnophallidae Morozov, 1955 in the second intermediate hosts (Trematoda, Digenea)].

    Science.gov (United States)

    Bartoli, P

    1981-01-01

    In Gymnophallidae life-cycle, the primary host is very often a Lamelli-branch, rarely a Prosobranch; the second intermediate host is usually a Pelecypod, rarely a Prosobranch or an Annelid. The first host is generally sedentary; consequently, cercariae are not widely spread. The second intermediate host cannot explore all the environment. These characters are not in favour of the parasite. Adaptation of Gymnophallid cycle consists in a very large cercarial productivity (several millions for only one first host). The recruiting modalities of Gymnophallid larvae by the second intermediate host are not always the same. Two different mechanisms have been discovered. The first one consists of a limited recruiting. The number of metacercariae is not always growing up during the host-life. This number depends on the volume of microhabitat. The top number is reached when microhabitat is saturated. The second one consists of a illimited recruiting. The number of parasites increases during all the second host life. This peculiarity is possible because the metacercariae are permanently carried out of the microhabitat where they had settled. Parasites are indeed progressively surrounded by pallial proliferations and become enclosed inside pockets of host tissues. Thus, microhabitat is always free of parasites and infection can go on. There must be a correlation between the mechanism of the recruitment of Gymnophallid larvae by a given second host and the characteristics of the environment where the life cycle unfolds. In confined environment (almost closed lagoons, brackish ponds) the number of cercariae is very large and the recruitment observed is limited. Then, the host-life is preserved. In wide open stations, where hydrodynamism is important, cercariae are scattered. The recruitment observed is illimited. This peculiarity is probably an adaptative factor permitting concentration of larvae in the second intermediate host. PMID:7258994

  11. Genotypic variation in host response to infection affects parasite reproductive rate.

    Science.gov (United States)

    Tavalire, Hannah F; Blouin, Michael S; Steinauer, Michelle L

    2016-02-01

    Parasite fitness is largely influenced by a variation in host response due to the host's genetic background. Here we investigated the impact of host genotype on pathogen success in the snail vector of its castrating parasite, Schistosoma mansoni. We infected five inbred lines of Biomphalaria glabrata with two infection doses and followed their growth, reproductive output and parasite production throughout the course of infection. There was no difference in resistance to infection among inbred lines, but lines varied in their responses to infection and the numbers of parasites produced. Snails did not compensate for castration by increasing their fecundity during the early phase of infection (fecundity compensation). However, some lines were able to delay parasite shedding for up to 30 weeks, thus prolonging reproduction before the onset of castration. Here we propose this strategy as a novel defense against castrating pathogens in snails. Gigantism, a predicted outcome of castration due to energy reallocation, occurred early in infection (gigantism were also characterised by a high parasite production rate and low survivorship, perhaps indicating energy reallocation into parasite production and costly immune defense. We observed no differences in total parasite production among lines throughout the entire course of infection, although lines differed in their parasite reproductive rate. The average rate of parasite production varied among lines from 1300 to 2450 cercariae within a single 2h shedding period, resulting in a total production of 6981-29,509 cercariae over the lifetime of a single snail. Regardless of genetic background, snail size was a strong predictor of parasite reproduction: each millimetre increase in snail size at the time of the first shed resulted in up to 3500 more cercariae over the lifetime of the snail. The results of this study provide a detailed picture of variation in hosts' responses to infection and the resulting impacts on parasite

  12. Surface expression patterns of defined glycan antigens change during Schistosoma mansoni cercarial transformation and development of schistosomula.

    Science.gov (United States)

    Smit, Cornelis H; Homann, Arne; van Hensbergen, Vincent P; Schramm, Gabriele; Haas, Helmut; van Diepen, Angela; Hokke, Cornelis H

    2015-12-01

    During the complex lifecycle of Schistosoma mansoni, a large variety of glycans is expressed. To many of these glycans, antibodies are induced by the infected host and some might be targets for vaccines or diagnostic tests. Spatial changes in glycan expression during schistosome development are largely unexplored. To study the surface-exposed glycans during the important initial stages of infection, we analyzed the binding of a panel of anti-glycan monoclonal antibodies (mAbs) to cercariae and schistosomula up to 72 h after transformation by immunofluorescence microscopy. The mAb specificity toward their natural targets was studied using a microarray containing a wide range of schistosomal N-glycans, O-glycans and glycosphingolipid glycans. With the exception of GalNAcβ1-4(Fucα1-3)GlcNAc (LDN-F), mono- and multifucosylated GalNAcβ1-4GlcNAc (LDN)-motifs were exposed at the surface of all developmental stages studied. Multifucosylated LDN-motifs were present on cercarial glycocalyx-derived O-glycans as well as cercarial glycolipids. In contrast, the Galβ1-4(Fucα1-3)GlcNAc (Lewis X) and LDN-F-motifs, also expressed on cercarial glycolipids, and in addition on a range of cercarial N- and O-glycans, became surface expressed only after transformation of cercariae to schistosomula. In line with the documented shedding of the O-glycan-rich cercarial glycocalyx after transformation these observations suggest that surface accessible multifucosylated LDN-motifs are mostly expressed by O-glycans in cercariae, but principally by glycosphingolipids in schistosomula. We hypothesize that these temporal changes in surface exposure of glycan antigens are relevant to the interaction with the host during the initial stages of infection with schistosomes and discuss the potential of these glycan antigens as intervention targets. PMID:26347524

  13. Fasciola hepatica: effect of the natural light level on cercarial emergence from temperature-challenged Galba truncatula

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    Vignoles Philippe

    2014-01-01

    Full Text Available As abrupt changes in water temperature (thermal shock triggered a significantly greater cercarial emergence of Fasciola hepatica from experimentally infected Galba truncatula, laboratory investigations were carried out to study the influence of light on cercarial emergence in snails subjected to a thermal shock every week (a mean of 12 °C for 3 h during the patent period. Thermal shock for these temperature-challenged (TC snails was carried out outdoors under artificial or natural light, or indoors under constant artificial light. Compared with the infected control snails always reared indoors at 20 °C, the number of cercariae in TC snails subjected to a thermal shock and natural light outdoors was significantly greater. The repetition of this experiment by subjecting TC snails to the same thermal shock indoors under an artificial light level ranging from 600 to 3000 lux did not show any significant difference among the numbers of cercariae in the different subgroups. A detailed analysis of the results noted in the TC snails subjected to natural light during the thermal shock demonstrated that the number of cercariae-releasing snails was significantly higher between 601 and 1200 lux and for the highest nebulosity values (7–8 octas, which corresponds to a sufficiently or completely overcast sky. Contrary to the intensity of artificial light, which did not influence cercarial emergence, the natural light level had a significant effect on this process when F. hepatica-infected snails were subjected to a regular thermal shock during the patent period.

  14. Atividade quimioprofilática de sabonetes contendo óleo essencial de frutos de Pterodon pubescens na esquistossomose mansoni Chemoprophylactic activity of soaps containing essential oil of Pterodon pubescens fruits in Schistosomiasis mansoni

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    D. Santos Filho

    1987-01-01

    Full Text Available It has been studied the chemoprophylactic action on experimental schistosomiasis of the essential oil from Pterodon pubescens "sucupira branca" as an additive through different formulations, in toilet soap. Immediately or 24 hours later, groups of mice were exposed by tail method to Schistosoma mansoni cercariae. After 45 days of the exposition, the protective action of these soaps were evaluated. The results showed different levels of protection, ranging from 29.0 to 100.0%. Further studies are on going with the most promising formulations.

  15. The first intermediate host of Paragonimus westermani in Sri Lanka.

    Science.gov (United States)

    Iwagami, Moritoshi; Rajapakse, R P V Jayanthe; Yatawara, Lalani; Kano, Shigeyuki; Agatsuma, Takeshi

    2009-01-01

    Freshwater snails (family Paludomidae, genus Paludomus) were collected from streams in Hedeniya and Peradeniya (the campus of Peradeniya University), Kandy district, Central Province, Sri Lanka, and found to harbor rediae and cercariae of a Paragonimus sp. These larvae were identified as Paragonimus westermani by using ITS2 DNA sequences. The infection rates of P. westermani in Paludomus sp. in Hedeniya and Peradeniya were 0.1% (one of 1014) and 0.2% (two of 1006), respectively. The snail has not been identified to species in the present study. This is the first report of the snail host of Paragonimus in Sri Lanka.

  16. Morphological description and life cycle of Paragonimus sp. (Trematoda: Troglotrematidae): causal agent of human paragonimiasis in Colombia.

    Science.gov (United States)

    Vélez, Imelda; Velásquez, Luz E; Vélez, Iván D

    2003-08-01

    The first morphological description is made of all stages of the life cycle of a Paragonimus species infecting humans in Colombia. Larval stages were obtained both in vitro and from field collections. Adult Paragonimus spp. are described. The aquatic snail Aroapyrgus sp. serves as an intermediate host of this species, both naturally and experimentally, yielding rediae and cercariae. Crabs (Hypolobocera bouvieri monticola and H. emberarum) were found to be the natural second intermediate hosts, and individuals of another crab species (Strengeria sp.) were also infected in the laboratory.

  17. Prosthogonimus cuneatus (Digenea, Prosthogonimidae in Bithynia tentaculata mollusks in Ukraine

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    Y. P. Zhytova

    2011-01-01

    Full Text Available Parthenitae and larvae of Prosthogonimus cuneatus Rudolphi, 1809 in the fresh water mollusk Bithynia tentaculata s were firstly found in the eastern Polissya (the Psel river bend, Sumy oblast. The paper presents the morphological characteristics of the P. cuneatus cercariae. Comparative analysis of the dimensional data of P. cuneatus sporocysts and larvae with their parthenitae and larvae described by T. A. Krasnolobova (1961, L. F. Filimonova and V. I. Shalyapina (1980, and E. Arystanov (1986 from B. tentaculata, B. inflata and B.caerulans mollusks was made.

  18. First report of Lymnaea columella Say, 1817 (Pulmonata: Lymnaeidae naturally infected with Fasciola hepatica (Linnaeus,1758 (Trematoda: Digenea in Argentina

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    Prepelitchi Lucila

    2003-01-01

    Full Text Available We report the first evidence of natural infection of Lymnaea columella with Fasciola hepatica in Argentina. A sample of 601 snails was collected in May 2003 in northeastern Corrientes, a province bounded on the north by Paraguay, on the east by Brazil and on the southeast by Uruguay. Among 500 examined snails, 44 (8.8% were exclusively infected with F. hepatica. Parasite identification was based on morphological features of cercariae from snails, and of eggs and adult flukes from Wistar rats. We discuss the events suggesting that an enzootic transmission cycle of F. hepatica has been recently established in northeastern Corrientes.

  19. Life history of Pygidiopsis crassus n. sp. (Trematoda, Digenea, Heterophyidae in the neotropical region

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    Margarita Ostrowski de Núñez

    1995-02-01

    Full Text Available The life cycle of Pygidiopsis crassus n. sp. was experimentally reproduced, starting from cercariae from naturally infected Littoridina parchappei collected from Lujan River and different ponds in Buenos Aires Province, Argentina. Metacercariae were found encysted in the body cavity of experimentally and naturally infected fishes Cnesterodon decemmaculatus and naturally infected Jenynsia lineata. Adults were obtained experimentally in chicks and mice. The natural host is unknown. The new species is compared with Pygidiopsis macrostomum Travassos 1928, from Rattus norvegicus and from Noctilio leporinus mastivus, differing in body and egg sizes, in the size relation of oral and ventral sucker and the shape of excretory vesicle.

  20. Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection on the reproduction of Biomphalaria glabrata (Pulmonata: Planorbidae).

    Science.gov (United States)

    Zakikhani, M; Rau, M E

    1998-10-01

    Infection with the digenean parasite Plagiorchis elegans dramatically reduced the reproductive output of Biomphalaria glabrata exposed to the parasite as juveniles or adults. The total number of eggs produced by infected snails was reduced to approximately 7 and 13% of control values, respectively. Parasitic castration was attributed to the presence of mother sporocysts that readily established in the tissues of this incompatible host. Infection did not result in the production of cercariae but significantly shortened the life span of juvenile and adult B. glabrata by approximately 23 and 10%, respectively. Plagiorchis elegans also castrated its compatible host, Stagnicola elodes. PMID:9794632

  1. Susceptibility of Biomphalaria tenagophila and Biomphalaria straminea to Schistosoma mansoni infection detected by low stringency polymerase chain reaction

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    JANNOTTI-PASSOS Liana Konovaloff

    2000-01-01

    Full Text Available In order to determine Schistosoma mansoni infection rates in Biomphalaria tenagophila and B. straminea, low stringency polymerase chain reaction (LS-PCR technique was used as a complementary method to light exposure technique. LS-PCR has already been standardized in our laboratory to detect the trematode DNA in B. glabrata. Higher S. mansoni infection rates were detected using conventional method and LS-PCR. The parasite DNA profile was detected in both species after 7-day exposure to miracidia, using LS-PCR. This technique enables early detection of schistosomiasis transmission focuses, in endemic areas, before the beginning of cercariae shedding.

  2. The life history of Pygidiopsis macrostomum Travassos, 1928 (Digenea: Heterophyidae

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    Susana Balmant Emerique Simões

    2009-02-01

    Full Text Available The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d´Orbigny, a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel, Jenynsia multidentata (Jenyns (new host records and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.

  3. Fascioliasis Control: In Vivo and In Vitro Phytotherapy of Vector Snail to Kill Fasciola Larva

    OpenAIRE

    Singh, D.K.; Kumari Sunita

    2011-01-01

    Snail is one of the important components of an aquatic ecosystem, it acts as intermediate host of Fasciola species. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. Life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria in the snail body. In vivo and in vitro toxicity of the plant products and their active component such as citral, ferulic acid, ...

  4. Marine envenomations and aquatic dermatology.

    Science.gov (United States)

    Soppe, G G

    1989-08-01

    Jellyfish stings are usually mild except those caused by species in the South Pacific. The box jellyfish can produce a severe cardiorespiratory insult. The sting of the Portuguese man-of-war is more potent than that of the common jellyfish. The Indo-Pacific area is the source of the most venomous bony fish. Many injuries can be avoided by wearing shoes when walking in shallow water or tide pools. Aquatic-related skin infections may involve unusual organisms. Swimmer's itch, a disease of freshwater bathing, is caused by cercariae. Seabather's eruption produces a rash in swimsuit-covered areas; the etiology is not clear. PMID:2569260

  5. Variant abiotic factors and the infection of Fasciola gigantica larval stages in vector snail Indoplanorbis exustus

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    Neha Singh

    2012-01-01

    Full Text Available The aquatic environment has numerous physical and chemical parameters that may influence the physiology and maturation rate of parasite found inside the vector snail. It may be possible that abiotic factors (temperature, pH, CO2, O2 and conductivity and higher population density of snails could promote the transmission of parasite and raise their local abundance. In the present paper, we examined that how these environmental factors affect the transmission of cercaria throughout the year 2009-2010. The infection of Fasciola gigantica larvae in Indoplanorbis exustus in Ramgarh Lake and GIDA pond was maximum in month of October (40% and minimum in month of November (8.33%. Trend of higher infection in I. exustus was observed in July to October. This study conclusively, shows that variant abiotic factors in different months of the year can significantly alter the infection rate and development process of larvae (sporocyst, redia and cercariae in the snail Indoplanorbis exustus. The paper also includes a discussion on the important factors that influence the timing of molluscicide operation for the control of fascioliosis in the Gorakhpur.

  6. Thermodynamics of miracidial survival and metabolism.

    Science.gov (United States)

    Morley, N J

    2012-10-01

    Miracidia are short-lived, non-feeding (lecithotrophic) free-living stages of trematodes, whose survival is potentially influenced by temperature. Climate change may result in elevated temperatures affecting trematode transmission. Therefore understanding their thermobiology forms an important step in determining the future dynamics of parasite populations. An empirical relationship exists between the mean expected life span of lecithotrophic larvae and the half life of their population (t(0·5)) and therefore t(0·5) is a good indicator of glycogen utilization. In this study experimental data on the effects of temperature on miracidial survival were compiled from the scientific literature and evaluated in terms of metabolism using Q 10 and Arrhenius activation energy (E* or μ). Temperature poorly influenced survival/metabolism with all miracidia having distinct zone(s) of thermostability. Overall there were few differences in Q(10) and E* values between most species temperature ranges whilst there were only limited strain-specific variations in thermal responses of laboratory-maintained Schistosoma mansoni. Miracidia demonstrated a trend of greater thermal resistance than cercariae. In particular, comparative studies on 4 strains of the same species of miracidia and cercariae showed little correlation in thermal biology between the 2 life-history stages. The importance of these results for trematode transmission under global climate change is discussed. PMID:22814411

  7. Verificação de antagonismo entre larvas de Schistosoma mansoni e larvas de outros Digenea em Biomphalaria tenagophila, molusco planobídeo de criadouro natural situado na região de Campinas, SP, Brasil Verification of the antagonism between larvae of Schistosoma mansoni and those of other Digenea in Biomphalaria tenagophila, a planorbid molusc from a natural breeding ground in the region of Campinas, SP, Brazil

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    Soely Maria Pissini Machado

    1988-12-01

    Full Text Available Foi observado o comportamento de larvas de S. mansoni em moluscos prévia e naturalmente infectados por larvas de outros Digenea. Foi verificado que as larvas de S. mansoni não se desenvolveram nos moluscos previamente infectados com purcocercárias longifurcadas com ocelos ou com furcocercárias longifurcadas sem ocelos. Observou-se resistência parcial ao desenvolvimento de S. mansoni nos moluscos previamente infectados por equinostomocercárias ou por distomocercárias com acúleo. A ausência de reação amebocitária em torno dos esporocistos de S. mansoni nos moluscos infectados por outros digenéticos parece indicar a não participação dos amebócitos na resistência oferecida ao desenvolvimento das larvas de S. mansoni.The objective of the present work is to study the development of S. mansoni larvae in snails found naturally infected by other digenetic trematode larvae. It was found that S. mansoni larvae did not develop in snails previoulsy infected by furcicercariae either with or without ocelli. Partial resistance to the development of S. mansoni was observed in snails previously infected by cercariae of Echinostomatidae or by cercariae with aculeus of Distomata. Absence of amoebocitary reaction around the S. mansoni sporocysts in snails previously infected by other digenetic trematodes indicates that amoebocytes did not play any role in the resistance mechanism.

  8. Seasonal variation in toxicity of citral against Fasciola larva

    Institute of Scientific and Technical Information of China (English)

    Kumari Sunita; Pradeep Kumar; Dinesh Kumar Singh

    2014-01-01

    Objective:To test whether the larvicidal activity of citral against Fasciola varies by season. Methods:Mortality of Fasciola larva in different month of year (2011-2012) in in vitro and in vivo condition were observed at 2 h, 4 h, 6 h and 8 h exposure of citral. Results:In vitro toxicity of citral against redia was highest in between the June to August (8 h LC50: 2.58-2.62 mg/L), whereas against cercaria 8 h LC50 was in between 3.44-2.62 mg/L. Highest in vivo toxicity against redia was noted in between June to August (8h LC50: 4.20-5.09 mg/L). The lowest toxicity was observed from November to April. The highest temperature, free carbon dioxide, and lowest pH, dissolved oxygen were observed from June to August. Conclusions:The present study conclusively shows that varying a biotic factor can significantly alter the in vitro and in vivo toxicity of citral against sporocyst redia and cercaria larva.

  9. Experimental evaluation of Candonocypris novaezelandiae (Crustacea: Ostracoda) in the biocontrol of Schistosomiasis mansoni transmission

    Science.gov (United States)

    Yousif, Fouad; Hafez, Sherif; El Bardicy, Samia; Tadros, Menerva; Taleb, Hoda Abu

    2013-01-01

    Objective To test Candonocypris novaezelandiae (Baird) (C. novaezelandiae), sub-class Ostracoda, obtained from the Nile, Egypt for its predatory activity on snail, Biomphalaria alexandrina (B. alexandrina), intermediate host of Schistosoma mansoni (S. mansoni) and on the free-living larval stages of this parasite (miracidia and cercariae). Methods The predatory activity of C. novaezelandiae was determined on B. alexandrina snail (several densities of eggs, newly hatched and juveniles). This activity was also determined on S. mansoni miracidia and cercariae using different volumes of water and different numbers of larvae. C. novaezelandiae was also tested for its effect on infection of snails and on the cercarial production. Results C. novaezelandiae was found to feed on the eggs, newly hatched and juvenile snails, but with significant reduction in the consumption in the presence of other diet like the blue green algae (Nostoc muscorum). This ostracod also showed considerable predatory activity on the free-living larval stages of S. mansoni which was affected by certain environmental factors such as volume of water, density of C. novaezelandiae and number of larvae of the parasite. Conclusions The presence of this ostracod in the aquatic habitat led to significant reduction of snail population, infection rate of snails with schistosme miracidia as well as of cercarial production from the infected snails. This may suggest that introducing C. novaezelandiae into the habitat at schistosome risky sites could suppress the transmission of the disease. PMID:23620849

  10. Biosensor for Hepatocellular Injury Corresponds to Experimental Scoring of Hepatosplenic Schistosomiasis in Mice

    Science.gov (United States)

    Sombetzki, Martina; Koslowski, Nicole; Doss, Sandra; Loebermann, Micha; Trauner, Michael; Reisinger, Emil C.; Sauer, Martin

    2016-01-01

    Severe hepatosplenic injury of mansonian schistosomiasis is caused by Th2 mediated granulomatous response against parasite eggs entrapped within the periportal tissue. Subsequent fibrotic scarring and deformation/sclerosing of intrahepatic portal veins lead to portal hypertension, ascites, and oesophageal varices. The murine model of Schistosoma mansoni (S. mansoni) infection is suitable to establish the severe hepatosplenic injury of disease within a reasonable time scale for the development of novel antifibrotic or anti-infective strategies against S. mansoni infection. The drawback of the murine model is that the material prepared for complex analysis of egg burden, granuloma size, hepatic inflammation, and fibrosis is limited due to small amounts of liver tissue and blood samples. The objective of our study was the implementation of a macroscopic scoring system for mice livers to determine infection-related organ alterations of S. mansoni infection. In addition, an in vitro biosensor system based on the detection of hepatocellular injury in HepG2/C3A cells following incubation with serum of moderately (50 S. mansoni cercariae) and heavily (100 S. mansoni cercariae) infected mice affirmed the value of our scoring system. Therefore, our score represents a valuable tool in experimental schistosomiasis to assess severity of hepatosplenic schistosomiasis and reduce animal numbers by saving precious tissue samples. PMID:27376078

  11. New scope on the relationship between rotifers and Biomphalaria alexandrina snails

    Institute of Scientific and Technical Information of China (English)

    Shereen Farouk Mossallam; Eglal Ibrahim Amer; Iman Fathy Abou-El-Naga

    2013-01-01

    Objective: To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes. Methods:Susceptible laboratory-bred Biomphalaria alexandrina (B. alexandrina) snails were exposed to lab-maintained rotifers; Philodina spp., two weeks before and after being infected with Schistosoma mansoni (S. mansoni) miracidia. The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails. Results:Contamination of B. alexandrina snails with philodina, two weeks before miracidial exposure, was found to hinder the preliminary development of S. mansoni cercariae inside the snail tissues. Furthermore, when snails were contaminated with rotifers two weeks post miracidial exposure; growth of already established cercariae was found to be retarded. The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial emergence, activity and infectivity along the four weeks duration of shedding. In the present study, comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs, which eventually was found to have had an adverse impact on reproduction, growth and survival of the parasite within the snail host, coupled with its performance outside the snail. Conclusions:In future biological control strategies of schistosomiasis, ritifers should be considered as a parasitic scourge of humanity.

  12. Confirmed local endemicity and putative high transmission of Schistosoma mansoni in the Sesse Islands, Lake Victoria, Uganda

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    Kabatereine Narcis B

    2011-03-01

    Full Text Available Abstract The Sesse Islands, in the Ugandan portion of Lake Victoria, have long been considered a low transmission zone for intestinal schistosomiasis. Based on observations of high prevalence of Schistosoma mansoni infection in the northern-most islands of this archipelago, a follow-up survey was conducted to ascertain whether transmission was endemic to this island group, combining parasitological and malacological surveys. Prevalence of intestinal schistosomiasis was again observed to be high, as was intensity of infections which, combined with low reported incidence of treatment, suggests that chemotherapy-based control initiatives are not being maximally effective in this region as high levels of population movement between islands and districts are confounding. The local disease transmission was confirmed by the observations of high abundance of Biomphalaria, as well as field-caught snails shedding S. mansoni cercariae. DNA sequencing of 12 cercariae revealed common mitochondrial cox1 haplotypes, as well as, novel ones, consistent with the high genetic diversity of this parasite in Lake Victoria. Intestinal schistosomiasis is firmly endemic in parts of the Sesse Islands and more broadly, this island group provides an insight into the future challenges to be faced by the Ugandan National Control Programme in regularly reaching these rather remote, inaccessible and largely itinerant communities.

  13. Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection of Biomphalaria glabrata (Pulmonata: Planorbidae) on a challenge infection with Schistosoma mansoni (Digenea: Schistosomatidae).

    Science.gov (United States)

    Zakikhani, M; Smith, J M; Rau, M E

    2003-02-01

    Prior exposure of Biomphalaria glabrata to the eggs of an incompatible digenean, Plagiorchis elegans, rendered this snail host less suitable to a compatible species, Schistosoma mansoni. Although P. elegans failed to develop patent infections in B. glabrata, it reduced the production of S. mansoni cercariae by 88%. Concomitantly, host attributes such as reproduction, growth, and survival were compromised. The effect of P. elegans infection was most severe among snails that, in addition, had developed patent schistosome infections. Although few S. mansoni cercariae were produced, egg production by B. glabrata was only 4% of control values. Furthermore, no doubly infected snails survived for more than 3 wk after patency, whereas controls experienced no mortality during the same time period. The above effects were attributable to the establishment and persistence of P. elegans sporocysts in the tissues of the incompatible snail host. Their indirect antagonistic interaction with thelarval stages of S. mansoni may be mediated, in part, through their long-term stimulation of the host's internal defense mechanisms. These findings are discussed with a view to use P. elegans and other plagiorchiid digeneans as agents in the biological control of snails and snail-borne diseases. PMID:12659305

  14. Pathogenicity of Trichobilharzia spp. for Vertebrates

    Science.gov (United States)

    Lucie, Lichtenbergová; Petr, Horák

    2012-01-01

    Bird schistosomes, besides being responsible for bird schistosomiasis, are known as causative agents of cercarial dermatitis. Cercarial dermatitis develops after repeated contact with cercariae, mainly of the genus Trichobilharzia, and was described as a type I, immediate hypersensitivity response, followed by a late phase reaction. The immune response is Th2 polarized. Primary infection leads to an inflammatory reaction that is insufficient to eliminate the schistosomes and schistosomula may continue its migration through the body of avian as well as mammalian hosts. However, reinfections of experimental mice revealed an immune reaction leading to destruction of the majority of schistosomula in the skin. Infection with the nasal schistosome Trichobilharzia regenti probably represents a higher health risk than infections with visceral schistosomes. After the skin penetration by the cercariae, parasites migrate via the peripheral nerves, spinal cord to the brain, and terminate their life cycle in the nasal mucosa of waterfowl where they lay eggs. T. regenti can also get over skin barrier and migrate to CNS of experimental mice. During heavy infections, neuroinfections of both birds and mammals lead to the development of a cellular immune response and axonal damage in the vicinity of the schistosomulum. Such infections are manifest by neuromotor disorders. PMID:23125918

  15. Pathogenicity of Trichobilharzia spp. for Vertebrates

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    Lichtenbergová Lucie

    2012-01-01

    Full Text Available Bird schistosomes, besides being responsible for bird schistosomiasis, are known as causative agents of cercarial dermatitis. Cercarial dermatitis develops after repeated contact with cercariae, mainly of the genus Trichobilharzia, and was described as a type I, immediate hypersensitivity response, followed by a late phase reaction. The immune response is Th2 polarized. Primary infection leads to an inflammatory reaction that is insufficient to eliminate the schistosomes and schistosomula may continue its migration through the body of avian as well as mammalian hosts. However, reinfections of experimental mice revealed an immune reaction leading to destruction of the majority of schistosomula in the skin. Infection with the nasal schistosome Trichobilharzia regenti probably represents a higher health risk than infections with visceral schistosomes. After the skin penetration by the cercariae, parasites migrate via the peripheral nerves, spinal cord to the brain, and terminate their life cycle in the nasal mucosa of waterfowl where they lay eggs. T. regenti can also get over skin barrier and migrate to CNS of experimental mice. During heavy infections, neuroinfections of both birds and mammals lead to the development of a cellular immune response and axonal damage in the vicinity of the schistosomulum. Such infections are manifest by neuromotor disorders.

  16. Infecção experimental do camundongo albino pelo Schistosoma mansoni. I - Estudo comparativo da eficácia de diferentes vias de infecção

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    Djaira Silva de Azevedo

    1976-08-01

    Full Text Available O presente trabalho tem por objetivo o estudo da eficácia comparativa de diferentes vias de infecção na equistossomose experimental do camundongo albino. Foram utilizados trinta camundongos albinos de ambos os sexos, com idade de dois meses, infectados com cerca de cem cercárias cada um e sacrificados três meses após a infecção. As vias de penetração empregadas foram: oral, transcutânea (por submersão parcial, imersão apenas da cauda e/ou colocação de cercárias em área depilada do abdômen e intraperitoneal. Os resultados obtidos demonstraram que a via mais eficaz foi transcutânea (sub-parcial, e que a maior mortalidade ocorreu no grupo infectado por via intraperitoneal.The comparative efficiency for different infecting routes in experimental schistosomiasis in Swiss albino mice has been studied. Thirty mice, both male and female, two months old, have been each infected with one humdred Schistosoma mansoni cercariae, and sacrificed three months later. The following infecting routes have been used: oral, percutaneous (partial body submersion, tail imersion and dropping of water containg cercariae on a shaved area of the anterior abdominal wall, and intra-peritoneal routes. Per-cutaneous route (partial submersion of the body proved to be the best and the highest mortality occurred in animais intra-peritoneally infected.

  17. Congenital infection of rabbits with Schistosoma japonicum and protective immunity of offspring

    Institute of Scientific and Technical Information of China (English)

    SHI You-en 石佑恩; Abdel-Moneim M Salim 沙里模; NING Chang-xiu 宁长修; GAN Yan 甘燕; ZHU Xiao-hua 朱晓华; PU Ling-yi 卜玲毅

    2004-01-01

    Background Recently congenital infection with Schistosoma japonicum (S. Japonicum) has been domonstrated in pigs, rabbits, mice and dogs. We explored the rabbit as an animal model for the congenital infection of schistosomiasis japonica and assessed the effect of a congenital S. Japonicum infection on the resistance of rabbit kittens to a postnatal challenge infection.Methods Sixteen pregnant New Zealand white rabbits were infected with a single dose of S. Japonicum cercariae. The exposed animals were divided into three groups according to the gestation age at the time of infection. Diagnosis of prenatally acquired S. Japonicum infection in the rabbit kittens was primarily based on serological tests in combination with parasitological and histopathological findings. Congenitally infected kittens were challenged percutaneously with 100 S. Japonicum cercariae to assess the effect of a congenital S. Japonicum infection on kitten resistance to a postnatal challenge infection.Conclusions This study demonstrates the possibility of congenital infection of S. Japonicum in rabbits and the resistance of congenitally infected kittens to a postnatal challenge infection. These results have important implications not only for epidemiological investigations, but also in designing government control programs for schistosomiasis.

  18. Anthelmintic Effect of Bacillus thuringiensis Strains against the Gill Fish Trematode Centrocestus formosanus

    Science.gov (United States)

    Mendoza-Estrada, Luis Javier; Hernández-Velázquez, Víctor Manuel; Arenas-Sosa, Iván; Flores-Pérez, Fernando Iván; Morales-Montor, Jorge; Peña-Chora, Guadalupe

    2016-01-01

    Parasitic agents, such as helminths, are the most important biotic factors affecting aquaculture, and the fluke Centrocestus formosanus is considered to be highly pathogenic in various fish species. There have been efforts to control this parasite with chemical helminthicides, but these efforts have had unsuccessful results. We evaluated the anthelmintic effect of 37 strains of Bacillus thuringiensis against C. formosanus metacercariae in vitro using two concentrations of total protein, and only six strains produced high mortality. The virulence (CL50) on matacercariae of three strains was obtained: the GP308, GP526, and ME1 strains exhibited a LC50 of 146.2 μg/mL, 289.2 μg/mL, and 1721.9 μg/mL, respectively. Additionally, these six B. thuringiensis strains were evaluated against the cercariae of C. formosanus; the LC50 obtained from the GP526 strain with solubilized protein was 83.8 μg/mL, and it could be considered as an alternative control of the metacercariae and cercariae of this parasite in the productivity systems of ornamental fishes. PMID:27294137

  19. Anthelmintic Effect of Bacillus thuringiensis Strains against the Gill Fish Trematode Centrocestus formosanus

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    Luis Javier Mendoza-Estrada

    2016-01-01

    Full Text Available Parasitic agents, such as helminths, are the most important biotic factors affecting aquaculture, and the fluke Centrocestus formosanus is considered to be highly pathogenic in various fish species. There have been efforts to control this parasite with chemical helminthicides, but these efforts have had unsuccessful results. We evaluated the anthelmintic effect of 37 strains of Bacillus thuringiensis against C. formosanus metacercariae in vitro using two concentrations of total protein, and only six strains produced high mortality. The virulence (CL50 on matacercariae of three strains was obtained: the GP308, GP526, and ME1 strains exhibited a LC50 of 146.2 μg/mL, 289.2 μg/mL, and 1721.9 μg/mL, respectively. Additionally, these six B. thuringiensis strains were evaluated against the cercariae of C. formosanus; the LC50 obtained from the GP526 strain with solubilized protein was 83.8 μg/mL, and it could be considered as an alternative control of the metacercariae and cercariae of this parasite in the productivity systems of ornamental fishes.

  20. Anthelmintic Effect of Bacillus thuringiensis Strains against the Gill Fish Trematode Centrocestus formosanus.

    Science.gov (United States)

    Mendoza-Estrada, Luis Javier; Hernández-Velázquez, Víctor Manuel; Arenas-Sosa, Iván; Flores-Pérez, Fernando Iván; Morales-Montor, Jorge; Peña-Chora, Guadalupe

    2016-01-01

    Parasitic agents, such as helminths, are the most important biotic factors affecting aquaculture, and the fluke Centrocestus formosanus is considered to be highly pathogenic in various fish species. There have been efforts to control this parasite with chemical helminthicides, but these efforts have had unsuccessful results. We evaluated the anthelmintic effect of 37 strains of Bacillus thuringiensis against C. formosanus metacercariae in vitro using two concentrations of total protein, and only six strains produced high mortality. The virulence (CL50) on matacercariae of three strains was obtained: the GP308, GP526, and ME1 strains exhibited a LC50 of 146.2 μg/mL, 289.2 μg/mL, and 1721.9 μg/mL, respectively. Additionally, these six B. thuringiensis strains were evaluated against the cercariae of C. formosanus; the LC50 obtained from the GP526 strain with solubilized protein was 83.8 μg/mL, and it could be considered as an alternative control of the metacercariae and cercariae of this parasite in the productivity systems of ornamental fishes. PMID:27294137

  1. Biosensor for Hepatocellular Injury Corresponds to Experimental Scoring of Hepatosplenic Schistosomiasis in Mice

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    Martina Sombetzki

    2016-01-01

    Full Text Available Severe hepatosplenic injury of mansonian schistosomiasis is caused by Th2 mediated granulomatous response against parasite eggs entrapped within the periportal tissue. Subsequent fibrotic scarring and deformation/sclerosing of intrahepatic portal veins lead to portal hypertension, ascites, and oesophageal varices. The murine model of Schistosoma mansoni (S. mansoni infection is suitable to establish the severe hepatosplenic injury of disease within a reasonable time scale for the development of novel antifibrotic or anti-infective strategies against S. mansoni infection. The drawback of the murine model is that the material prepared for complex analysis of egg burden, granuloma size, hepatic inflammation, and fibrosis is limited due to small amounts of liver tissue and blood samples. The objective of our study was the implementation of a macroscopic scoring system for mice livers to determine infection-related organ alterations of S. mansoni infection. In addition, an in vitro biosensor system based on the detection of hepatocellular injury in HepG2/C3A cells following incubation with serum of moderately (50 S. mansoni cercariae and heavily (100 S. mansoni cercariae infected mice affirmed the value of our scoring system. Therefore, our score represents a valuable tool in experimental schistosomiasis to assess severity of hepatosplenic schistosomiasis and reduce animal numbers by saving precious tissue samples.

  2. Radiation-resistant acquired immunity of vaccinated mice to Schistosoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Aitken, R.; Coulson, P.S.; Dixon, B.; Wilson, R.A.

    1987-11-01

    Vaccination of mice with attenuated cercariae of Schistosoma mansoni induces specific acquired resistance to challenge infection. This resistance is immunologically-mediated, possibly via a delayed-type hypersensitivity. Studies of parasite migration have shown that the protective mechanism operates most effectively in the lungs of vaccinated mice. We have probed the mechanism by exposing mice to 500 rads of gamma radiation before challenge infection. Our results show that the effector mechanism operative against challenge larvae is resistant to radiation. In contrast, classical immune responses are markedly suppressed by the same treatment. While leukocyte populations in the blood fall dramatically after irradiation, numbers of cells recoverable by bronchoalveolar lavage are unaffected. We suggest that vaccination with attenuated cercariae establishes populations of sensitized cells in the lungs which trigger the mechanism of resistance when challenge schistosomula migrate through pulmonary capillary beds. Although the cells may be partially disabled by irradiation, they remain responsive to worm antigens and thereby capable of initiating the elimination mechanism. This hypothesis would explain the radiation resistance of vaccine-induced immunity to S. mansoni.

  3. Immunity to Schistosoma mansoni in congenitally athymic, irradiated and mast cell-depleted rats

    Energy Technology Data Exchange (ETDEWEB)

    Ford, M.J.; Bickle, Q.D.; Taylor, M.G.

    1987-04-01

    Immunity to Schistosoma mansoni was investigated in congenitally athymic (Nu/Nu) rats, irradiated rats and in mast cell-depleted rats. Nu/Nu rats failed to develop significant resistance following vaccination with irradiated cercariae, although Nu/Nu recipients of serum from vaccinated Fischer rats (VRS) manifested resistance comparable to heterozygous controls, suggesting that T-cells were required in the induction of resistance but were not involved in the efferent arm of antibody-dependent elimination. Radiosensitive cells (including eosinophils, basophils, neutrophils, lymphocytes and mast cells) were apparently not essential for the antibody-dependent elimination of lung or post-lung stages since irradiated (700-750 rad.) recipients of VRS manifested comparable degrees of resistance to unirradiated controls in spite of a greater than 85% reduction in total blood leucocyte counts after irradiation. Depletion of 99% of tissue mast cells by treatment of rats with Compound 48/80 had no significant effect on the attrition of a challenge infection in rats rendered immune by vaccination with irradiated cercariae or by transfer of VRS. However, there was a significant increase in worm recovery in unimmunized and mast cell-depleted or irradiated rats, indicating that mast cells and perhaps other radio-isotope sensitive cells may be involved in innate resistance.

  4. In vivo T cell depletion regulates resistance and morbidity in murine schistosomiasis

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, S.M.; Linette, G.P.; Doughty, B.L.; Byram, J.E.; Von Lichtenberg, F.

    1987-08-01

    These studies assessed the roles of subpopulations of T lymphocytes in inducing and modulating resistance to schistosomiasis and thereby influencing subsequent morbidity. C57BL/6 mice were depleted in vivo of Lyt-1+, Lyt-2+, and L3T4+ cells by the daily administration of monoclonal antibodies. The development of protective immunity, induced by exposure to irradiated Schistosoma mansoni cercariae as expressed in depleted animals, was compared to that demonstrated in undepleted, normal, and congenitally athymic C57BL/6 mice. The development of morbidity was determined by spleen weight, portal pressure and reticuloendothelial system activity. The results indicated that depletion of specific subpopulations of T lymphocytes minimally affected the primary development of parasites; however, depletion strongly influenced the development of resistance to the parasite and subsequent morbidity due to infection. Depletion of T lymphocytes by anti-Lyt-1+ or anti-L3T4+ antibody decreased the development of resistance, antibody and delayed-type hypersensitivity directed against schistosome antigens. Morbidity due to disease was increased. Depletion of Lyt-2+ cells produced opposite changes with augmented resistance and reduced morbidity. Congenitally athymic mice developed minimal resistance and morbidity. Moreover, resistance was inversely related to the morbidity shown by a given animal. These studies indicate that the development of protective immunity to S. mansoni cercariae is regulated by discrete subpopulations of T lymphocytes. The feasibility of decreasing morbidity by increasing specific immunologically mediated resistance is suggested.

  5. Experimental evaluation of Candonocypris novaezelandiae (Crustacea:Ostracoda) in the biocontrol of Schistosomiasis mansoni transmission

    Institute of Scientific and Technical Information of China (English)

    Fouad Yousif; Sherif Hafez; Samia El Bardicy; Menerva Tadros; Hoda Abu Taleb

    2013-01-01

    Objective: To test Candonocypris novaezelandiae (Baird) (C. novaezelandiae), sub-class Ostracoda, obtained from the Nile, Egypt for its predatory activity on snail, Biomphalariaalexandrina (B. alexandrina), intermediate host of Schistosoma mansoni (S. mansoni) and on the free-living larval stages of this parasite (miracidia and cercariae). Methods:The predatory activity of C. novaezelandiae was determined on B. alexandrina snail (several densities of eggs, newly hatched and juveniles). This activity was also determined on S. mansoni miracidia and cercariae using different volumes of water and different numbers of larvae. C. novaezelandiae was also tested for its effect on infection of snails and on the cercarial production. Results: C. novaezelandiae was found to feed on the eggs, newly hatched and juvenile snails, but with significant reduction in the consumption in the presence of other diet like the blue green algae (Nostoc muscorum). This ostracod also showed considerable predatory activity on the free-living larval stages of S. mansoni which was affected by certain environmental factors such as volume of water, density of C. novaezelandiae and number of larvae of the parasite.Conclusions:The presence of this ostracod in the aquatic habitat led to significant reduction of snail population, infection rate of snails with schistosme miracidia as well as of cercarial production from the infected snails. This may suggest that introducing C. novaezelandiae into the habitat at schistosome risky sites could suppress the transmission of the disease.

  6. r-Sm14 - pRSETA efficacy in experimental animals

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    Ramos Celso Raul Romero

    2001-01-01

    Full Text Available Previous studies carried out with Sm14 in experimental vaccination against Schistosoma mansoni or Fasciola hepatica infections were performed with recombinant Sm14 (rSm14 produced in Escherichia coli by the pGEMEX system (Promega. The rSm14 was expressed as a 40 kDa fusion protein with the major bacteriophage T7 capsid protein. Vaccination experiments with this rSm14 in animal models resulted in consistent high protective activity against S. mansoni cercariae challenge and enabled rSm14 to be included among the vaccine antigens endorsed by the World Health Organization for phase I/II clinical trials. Since the preparation of pGEMEX based rSm14 is time consuming and results in low yield for large scale production, we have tested other E. coli expression systems which would be more suitable for scale up and downstream processing. We expressed two different 6XHis-tagged Sm14 fusion proteins in a T7 promoter based plasmids. The 6XHis-tag fusions allowed rapid purification of the recombinant proteins through a Ni+2-charged resin. The resulted recombinant 18 and 16 kDa proteins were recognized by anti-Sm14 antibodies and also by antiserum against adult S. mansoni soluble secreted/excreted proteins in Western-Blot. Both proteins were also protective against S. mansoni cercariae infection to the same extent as the rSm14 expressed by the pGEMEX system.

  7. Laboratory assessment of molluscicidal and cercariacidal effects of Glinus lotoides fruits

    Science.gov (United States)

    2014-01-01

    Background The negative impact of synthetic molluscicides on the environment and their high cost necessitated search for an alternative approach of using plant extracts for the control of schistosomiasis. The objective of this study was, therefore, to evaluate aqueous and ethyl acetate crude extracts of Glinus lotoides fruits for their cercariacidal activity and molluscicidal effect against schistosome snail intermediate hosts. Methods Assessment of the molluscicidal activity against Biomphalaria pfeifferi was made by immersion method in accordance with WHO guideline. The results of mortality were statistically analyzed using probit analysis. The attenuating effect of the plant on Schistosoma mansoni cercariae was determined using establishment of adult worms as a parasitological parameter post exposure. Results The 24 and 48 hour-LC50 values for the aqueous extract of G. lotoides fruits were 47.1 and 44.1 mg/L, respectively, whereas that of ethyl acetate were 66.1 and 59.6 mg/L, respectively. The 24 and 48 hour LC90 values for the aqueous extract of G. lotoides fruits were 56.96 and 51.0 mg/L, respectively, while that of ethyl acetate were 77.2 and 70.0 mg/L, respectively. The in vitro cercariacidal activity was determined after 2 hrs of exposure to the aqueous plant extract. It was found out that the LC50 and LC90 values were 18.7 and 41.7 mg/L, respectively. Besides, infectivity of Schistosoma mansoni cercariae to mice was determined by exposing mice to cercariae pre-treated with the sub-lethal concentrations (3.7, 11.6 and 18.7 mg/L) of the aqueous extract. A significant reduction in worm burden in mice was obtained at 11.6 mg/L (p molluscicidal activity against B. pfeifferi snails and cercariacidal activity against S. mansoni. Yet, further comprehensive evaluation is recommended for the possible use of G. lotoides against B. pfeifferi and the schistosome parasite. PMID:24713133

  8. Esquistossomose: nova ocorrência de Biomphalaria straminea em Belo Horizonte, Minas Gerais Schistosomiasis: new occurrence of Biomphalaria straminea in Belo Horizonte, Minas Gerais

    Directory of Open Access Journals (Sweden)

    Cecília Pereira de Souza

    1996-12-01

    Full Text Available Em Belo Horizonte, Minas Gerais, Brasil, a Biomphalaria straminea é encontrada na região da Pampulha. Recentemente, o molusco foi encontrado em valas da antiga Barragem de Santa Lúcia, foco extinto de esquistossomose transmitida por B. glabrata. Os moluscos foram coletados e examinados para verificar se estavam naturalmente infectados com Schistosoma mansoni. Os exemplares negativos foram usados para criação ou infecção com a cepa LE de S. mansoni, mantida no laboratório, e outra cepa VGS, obtida de ovos de fezes de escolar de Belo Horizonte. Dentre 1.890 moluscos capturados em 1994 e 1995, nenhum estava infectado com S. mansoni. Dentre 87 exemplares coletados no criadouro e expostos à cepa LE, nove (10,3% eliminaram cercárias; dentre 83 moluscos da F1, dez (12,0% eliminaram cercárias e dentre 88 exemplares coletados e expostos à cepa VGS, dez (11,3% eliminaram cercárias. Em Belo Horizonte, a esquistossomose é transmitida por B. glabrata e B. tenagophila. Entretanto, atualmente existe o risco de aparecimento de novo foco, no qual a B. straminea poderá vir a ser a transmissora, se medidas profiláticas adequadas não forem tomadas pelas autoridades responsáveis pela construção de um parque e lago no local.In Belo Horizonte, Minas Gerais, Brazil, the snail Biomphalaria straminea was found in the Pampulha region. Recently the snail was found in ditches in the old Santa Lúcia Reservoir, a now-extinct focus of schistosomiasis transmission by B. glabrata. The snails were collected and examined to verify whether they were naturally infected with Schistosoma mansoni. Negative specimens were used for breeding or infection with the LE strain of S. mansoni from the laboratory and another strain obtained from eggs found in the feces of a schoolchild (VGS from Belo Horizonte. Among the 1890 snails collected from 1994 to 1995, none were infected with S. mansoni. Among 87 snails collected and exposed to the LE strain, 9 (10.3% shed cercariae

  9. Freshwater snails and crabs infected with Paragonimus in northern suburban of Guangzhou%广州北部山区螺种、蟹类及其感染并殖吸虫的调查

    Institute of Scientific and Technical Information of China (English)

    赵太平; 陆予云; 沈浩贤; 龙小山; 魏桂芬; 罗健留

    2014-01-01

    Objective To investigate the species of freshwater snails, crabs and their natural infection of Paragonimus cercaria, metacercariae in northern suburban of Guangzhou, and understand the distribution of Paragonimus. Methods The freshwater snails and crabs were collected from mountain streams to detect the cercaria and metacercariae of Paragonimus and their identify categories. Results The average infection rate of cercaria in Liangkou town, Lvtian town (Conghua city) and Nankunshan (Longmen county) was 0.32%, 0.15% and 0.03%, respectively. The snail species in both Liangkou town and Nankunshan was identified as Semisulcospira libertina, Tricula in Lvtian town. The average infection rate of metacercariae in Liangkou town, Lvtian town and Nankunshan was 100%, 36.73% and 100%, respectively. The crab species in both Liangkou town and Nankunshan were identified as Sinopotamon pinheense, and Nanhaipotomon pinyuanense in Lvtian town. The cercaria and metacercariae were not found in the samples of freshwater snails and crabs in Zengcheng city and Xinfeng County. Conclusions It,s the first report that Liangkou town and Lvtian town of Conghua city in northern suburban of Guangzhou is the ultra- high infectious focus of Paragonimus westermani infection(GradeⅠ), and Nankunshan town is the moderate infectious focus of Paragonimus skrjabini. (GradeⅢ).%目的:调查广州北部(从化市、增城市、龙门县、新丰县)山区淡水螺、淡水蟹感染并殖吸虫尾蚴、囊蚴的情况,了解并殖吸虫流行分布状况。方法采集山溪螺蛳、溪蟹,检查并殖吸虫尾蚴、囊蚴,鉴定并殖吸虫虫种。结果从化市良口镇螺蛳尾蚴感染率0.32%,螺种为放逸短沟蜷;溪蟹囊蚴感染率100%,蟹种为平和华溪蟹。吕田镇螺蛳尾蚴感染率0.03%,螺种为拟钉螺;溪蟹感染率为36.73%,蟹种为平远南海溪蟹。龙门县南昆山尾蚴感染率0.15%,螺种为放逸短沟蜷;溪蟹囊蚴感染率为100%

  10. [Comparative study on hepatic and intestinal pathological changes in different animals with schistosomiasis japonica].

    Science.gov (United States)

    Zhou, J; Cheng, R; Zeng, X; Yi, X; Luo, X; Wang, L

    1995-01-01

    The pathological changes of livers and intestines were compared among cats, dogs and rabbits infected with Schistosoma japonicum cercariae for three months. The resuults showed that the most serious lesions were seen in rabbits while the slightest were in cats. The granulomatous response was more distinct in livers than in intestines in all the three animals. The increment ratio of egg granuloma in livers was 3.52, 2.64 and 1.81 in rabbits, dogs and cats, respectively. The eggs were deposited singly or in strings, few granuloma formation was observed in the intestines. In addition to inflammatory infiltration, swelling and/or dropping of mucosa the gland destruction and ulcer were also observed in the mucosa. The investigation demonstrated that pathological lesions varied in different animal species.

  11. Evolution of sarcoma 180 (ascitic tumor in mice infected with Schistosoma mansoni

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    Fausto Edmundo Lima Pereira

    1986-03-01

    Full Text Available Mice infected with 60 cercariae of Schistosoma mansoni were more resistant to the sarcoma 180 ascites tumor. Tumor inoculation was performed 50 days after schistosoma infection and the animals were observed and weighed at 48 hours intervals for development and progression of malignancy. In infected mice the weight gain (ascites formation started later and was shorter than in uninfected Controls. Also, the number of tumor cells into the peritoneal cavity 72h after tumor implantation was shorter in infected group than incontrols. This in creased resistance against a transplantable tumor probably is related to the effect of endotoxin on tumoricidal activity of macrophages activated by the infection. The immunodepression induced by Schistosoma mansoni infection enhances the proliferation of endogenous bacteria increasing the amount of endotoxin absorbed from the gut.

  12. Development of Schistosoma mansoni in Biomphalaria tenagophila, Biomphalaria straminea and Biomphalaria glabrata Desenvolvimento do Schistosoma mansoni em Biomphalaria tenagophila, Biomphalaria straminea e Biomphalaria glabrata

    Directory of Open Access Journals (Sweden)

    Cecilia Pereira de Souza

    1995-06-01

    Full Text Available A comparative study of the development of Schistosoma mansoni during the intra-molluscan phase was made by means of histological sections of Biomphalaria tenagophila, B. straminea and B. glabrata from Brazil. Two hundred snails of each species were individually exposed to 50 miracidia of the S. mansoni, AL line. No larvae were observed in the snails fixed 72 h after exposure. In specimens shedding cercariae, 31 days after exposure tissue reactions encapsulating the larvae were seen in B. tenagophila and B. straminea, in the head-foot, mantle collar and renal ducts. No tissue reactions occurred in the digestive glands of these two species. In B. glabrata the presence of numerous sporocysts and cercariae without tissue reactions was observed in the digestive gland, and other organs. The levels of infection of the snails and the average numbers of cercariae shed per day were 32.6% and 79±90 respectively for B. tenagophila, 11.3% and 112±100 for B. straminea and 75.3% and 432±436 for B. glabrata. The lower levels of infection and average numbers of cercariae shed by B. tenagophila and B. straminea are thus related to their more potent internal defense systems.Foi feito estudo comparativo do desenvolvimento do Schistosoma mansoni na fase intra-molusco, através de cortes histológicos, em Biomphalaria tenagophila, B. straminea e B. glabrata. Duzentos moluscos de cada espécie foram expostos individualmente a 50 miracídios de S. mansoni da linhagem AL. Nenhuma larva foi observada nos exemplares fixados 72 horas após a exposição. Nos exemplares eliminando cercárías, 31 dias após a exposição, foram observadas reações teciduais de encapsulamento de larvas em B. tenagophila e B. straminea, na região cefalopodal, colar do manto e dutos renais. Nas glândulas digestivas das duas espécies não foram observadas reações. Em B. glabrata foi registrada a presença de numerosos esporocistos e cercárias sem reação tecidual na gl

  13. Screening of some Nigerian plants for molluscicidal activity.

    Science.gov (United States)

    Kela, S L; Ogunsusi, R A; Ogbogu, V C; Nwude, N

    1989-01-01

    Methanolic (MEOH), evaporated crude water (ECW) and unevaporated crude water (UECW) extracts of 25 Nigerian plants, used for different medicinal and domestic purposes were screened for molluscacidal activity on laboratory-reared Lymnaea natalensis Krauss. Seven of the plants were not active; extracts from 18 (72 per cent) of the plants, some of which are renowned fish poisons, had molluscicidal activity. These were Acacia nilotica, Aristolochia albida, Balanites aegyptiaca, Blighia sapida, Boswellia dalzielii, Detarium microcarpum, Gnidia kraussiana, Kigelia africana, Nauclea latifolia, Opilia celtidefolia, Parkia clappertoniana, Polygonum limbatum, Pseudocedrela kotschyi, Sclerocarya birrea, Securidaca longipedunculata, Ximenia americana, Vetiveria nigritana and Ziziphus abyssinica. The LC50 of these extracts were determined. It is strongly recommended that the toxic effects of these extracts against fish, cercariae, snail eggs and mammals be further investigated so as to determine the right concentration, especially for use in fish ponds. PMID:2626572

  14. Vaccination of Goats with 31 kDa and 32 kDa Schistosoma japonicum Antigens by DNA Priming and Protein Boosting

    Institute of Scientific and Technical Information of China (English)

    Lianfei Tang; Zhijun Zhou; Yuxiao Chen; Yonghui Luo; Linqian Wang; Liyu Chen; Fushen Huang; Xianfang Zeng; Xinyuan Yi

    2007-01-01

    Two Schistosoma japonicum vaccine candidate antigens Sj 31 and Sj 32, which have shown particular promise to induce protective immunity in mice, were used to immunize goats by using a DNA priming-protein boosting strategy in present work. DNA vaccine formulations of the two antigens (VRSj31 and VRSj32) were produced and injected intramuscularly twice at a 2-week interval and then recombinant proteins (rSj31 and rSj32) together with Freund Complete Adjuvant (FCA) were used to boost the goats. The experiment was repeated in different batche cercariae. A strong anamnestic antibody response was induced after boost. A significant reduction of liver egg counts and miracidial hatching was showed in both experiments. Significant protections against challenge infection were elicited with 31.6% of percentage reduction for worm recovery in the second experiment and 20.9% in the first experiment, respectively.

  15. Immunostimulatory effects of extract of Pulicaria crispa before and after Schistosoma mansoni infection.

    Science.gov (United States)

    Maghraby, Amany S; Shalaby, Nagwa; Abd-Alla, Howida I; Ahmed, Samia A; Khaled, Hussein M; Bahgat, Mahmoud M

    2010-01-01

    The immunostimulatory effects of methanolic extract from Pulicaria crispa were investigated in mice before and after infection with Schistosoma mansoni. Mice were subjected for daily intra-peritoneal injection by the extract (33 ng/mouse) for 10 successive days followed by infecting every mouse with 100 S. mansoni cercariae. Treatment with the extract induced significant increase (p < 0.05) in sera-IL-2 before and after infection. Upon using soluble worm antigen preparation or cancer bladder homogenates as antigens in ELISA, the detected levels of IgG were significantly (p < 0.05) higher in sera from treated-infected mice than untreated P. crispa infected mice. Using crude Escherichia coli lysate as an antigen in ELISA, it was detected a significant (p < 0.05) increase in IgG levels in sera from the extract-treated mice before and after infection.

  16. The killifish, fundulus heteroclitus, second intermediate host of the trematode, Ascocotyle (Phagicola) dimunuta

    Science.gov (United States)

    1955-01-01

    Ascocotyle (Phagicola) diminuta was described by Stunkard and Haviland (1924)from the intestine of wild rats collected at the Clason Point dump near New York by the City Board of Health. Feeding experiments have demonstrated that metacercariae encysted in the gills of the common killifish, Fundulus hetero clitus, are stages in the life-cycle of this parasite. The larvae have been found also, although rarely and in small numbers, in the gills of the striped killifish, Fundulus majalis. Since both species of Fundulus are susceptible, it appears probable that the habits of F. heteroclitus occasion greater exposure of this species to the cercariae. It is possible that infection of the fishes occurs during the spawning season when they are in water of low salinity. The asexual stages of these trematodes and the mollusks which harbor them are yet unknown.

  17. Compatibility of Ugandan Schistosoma mansoni isolates with Biomphalaria snail species from Lake Albert and Lake Victoria

    DEFF Research Database (Denmark)

    Adriko, Moses; Standley, Claire J.; Tinkitina, Benjamin;

    2013-01-01

    In order to investigate the capacity of being intermediate host for Schistosoma mansoni, the Ugandan F1 generation of Biomphalaria snail species that were laboratory-bred from parent populations originally collected from either Lake Victoria or Lake Albert was challenged with sympatric and non......-sympatric S. mansoni isolates. After a prepatent period of 20 days, a daily 10-hourly snail shedding for cercariae was done to determine the infection rate, cercarial production per hour and survival period of infected snails. The study suggests that when parasite strains from a different geographical origin...... is used for infection, survival of infected snails increase, leading to an increased transmission potential. Although earlier literature had indicated that the Lake Victoria Biomphalaria sudanica is refractory to S. mansoni, we showed that all Ugandan Biomphalaria spp., including B. sudanica from all...

  18. Acute human schistosomiasis mansoni

    Directory of Open Access Journals (Sweden)

    Ana Rabello

    1995-04-01

    Full Text Available The acute schistosomiasis is the toxemic disease that follow the Schistosoma cercariae active penetration trough screen in the immunologicaly naive vertebrate host. The clinical picture starts two to eight weeks after the first contact with the contaminated water. Susceptible patients present a syndrome comprising fever, diarrhea, toxemia and hepatosplenomegaly. Diagnosis is based on epidemiological and clinical features, presence of Schistosoma eggs in the feces, enlargement of abdominal lymph nodes by ultrasonography and by detection of high antibodies levels against the antigen keyhole limpet haemocyanin. Different rates of cure have been observed with specific medication and for the most severe clinical presentations the use of steroids reduces the systemic and allergic manifestations.

  19. Ocorrência de infecção natural de Fasciola hepatica Linnaeus, 1758 em Lymnaea columella Say, 1817 no Vale do Paraíba, SP, Brasil Natural infection by Fasciola hepatica in Lymnaea columella in the Paraíba river valley, S. Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Marlene Tiduko Ueta

    1980-06-01

    Full Text Available Foram registradas em Piquete, no vale do rio Paraíba do Sul (SP, Brasil, taxas de 1,22% e 0,14% de infecção natural em Lymnaea columella, por Fasciola hepatica. Em um único exemplar de Lymnaea columella dentre os 1.052 examinados, foram observadas rédias com xifidiocercárias, rédias com cercárias de Fasciola hepatica e metacercárias de Echinostomatidae.Infection rates of 1.22% and 0.14% were obtained in Lymnaea columella snails naturally infected by Fasciola hepatica. Samples of the snails were collected in Piquete, a municipality of Paraíba do Sul, a river valley area in the State of S. Paulo. Also observed was one of the 1052 specimen of the Lymnaea columella rediae which had xiphidiocercariae and rediae with Fasciola hepatica cercariae and metacercariae of Echinostomatidae.

  20. Altered patterns of gene expression underlying the enhanced immunogenicity of radiation-attenuated schistosomes.

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    Gary P Dillon

    Full Text Available BACKGROUND: Schistosome cercariae only elicit high levels of protective immunity against a challenge infection if they are optimally attenuated by exposure to ionising radiation that truncates their migration in the lungs. However, the underlying molecular mechanisms responsible for the altered phenotype of the irradiated parasite that primes for protection have yet to be identified. METHODOLOGY/PRINCIPAL FINDINGS: We have used a custom microarray comprising probes derived from lung-stage parasites to compare patterns of gene expression in schistosomula derived from normal and irradiated cercariae. These were transformed in vitro and cultured for four, seven, and ten days to correspond in development to the priming parasites, before RNA extraction. At these late times after the radiation insult, transcript suppression was the principal feature of the irradiated larvae. Individual gene analysis revealed that only seven were significantly down-regulated in the irradiated versus normal larvae at the three time-points; notably, four of the protein products are present in the tegument or associated with its membranes, perhaps indicating a perturbed function. Grouping of transcripts using Gene Ontology (GO and subsequent Gene Set Enrichment Analysis (GSEA proved more informative in teasing out subtle differences. Deficiencies in signalling pathways involving G-protein-coupled receptors suggest the parasite is less able to sense its environment. Reduction of cytoskeleton transcripts could indicate compromised structure which, coupled with a paucity of neuroreceptor transcripts, may mean the parasite is also unable to respond correctly to external stimuli. CONCLUSIONS/SIGNIFICANCE: The transcriptional differences observed are concordant with the known extended transit of attenuated parasites through skin-draining lymph nodes and the lungs: prolonged priming of the immune system by the parasite, rather than over-expression of novel antigens, could thus

  1. Consistent pattern of local adaptation during an experimental heat wave in a pipefish-trematode host-parasite system.

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    Susanne H Landis

    Full Text Available Extreme climate events such as heat waves are expected to increase in frequency under global change. As one indirect effect, they can alter magnitude and direction of species interactions, for example those between hosts and parasites. We simulated a summer heat wave to investigate how a changing environment affects the interaction between the broad-nosed pipefish (Syngnathus typhle as a host and its digenean trematode parasite (Cryptocotyle lingua. In a fully reciprocal laboratory infection experiment, pipefish from three different coastal locations were exposed to sympatric and allopatric trematode cercariae. In order to examine whether an extreme climatic event disrupts patterns of locally adapted host-parasite combinations we measured the parasite's transmission success as well as the host's adaptive and innate immune defence under control and heat wave conditions. Independent of temperature, sympatric cercariae were always more successful than allopatric ones, indicating that parasites are locally adapted to their hosts. Hosts suffered from heat stress as suggested by fewer cells of the adaptive immune system (lymphocytes compared to the same groups that were kept at 18°C. However, the proportion of the innate immune cells (monocytes was higher in the 18°C water. Contrary to our expectations, no interaction between host immune defence, parasite infectivity and temperature stress were found, nor did the pattern of local adaptation change due to increased water temperature. Thus, in this host-parasite interaction, the sympatric parasite keeps ahead of the coevolutionary dynamics across sites, even under increasing temperatures as expected under marine global warming.

  2. Relação entre a patogenicidade do Schistosoma mansoni em camundongos e a susceptibilidade do molusco vetor: III. Mortalidade, pesos corporal e das vísceras Relationship between the pathogenicity of Schistosoma mansoni in mice and the susceptibility of the vector mollusc: III. Mortality, body weight and viscera weights

    Directory of Open Access Journals (Sweden)

    Eliana Maria Zanotti-Magalhães

    1995-08-01

    Full Text Available Estudou-se a relação entre o desenvolvimento da hepatomegalia, da esplenomegalia, peso corporal e taxa de mortalidade em camundongos experimentalmente infectados por Schistosoma mansoni com o grau de susceptibilidade de Biomphalaria glahrata e B. tenagophila nas quais se desenvolveram as cercárias infectantes respectivamente, das linhagens BH e SJ. Foram utilizados como hospedeiro definitivo camundongos Swiss, SPF e como hospedeiros intermediários populações de moluscos selecionados geneticamente para o caráter susceptibilidade. Foram observados menores pesos corporais e das visceras em camundongos infectados com cercárias provenientes de moluscos que apresentaram elevado grau de susceptibilidade. A maior susceptibilidade dos moluscos à infecção pelo S. mansoni correspondeu a uma menor sobrevivência dos camundongos infectados. Os resultados fazem crer que a maior adaptação do parasita ao hospedeiro intermediário, traduzidos pelas taxas mais elevadas de susceptibilidade, pode levar a um comportamento diferente deste parasita no hospedeiro definitivo.The relationship between the development of hepatomegaly, splenomegaly, body weight and mortality rate and the degree of susceptibility of Biomphalaria glabrata and B. tenagophila at which infective cercariae developed was studied. The study utilized Swiss mice, SPF, as definitive hosts and populations of snails genetically selected for character susceptibility as intermediate hosts. Low body weight and smaller viscera were observed in infected mice with cercariae originating from snails that showed a high degree of susceptibility. The higher susceptibility of molluscs infected with S. mansoni corresponded to a lower survival of the infected mice. These results lead to the conclusion that the higher degree of adaptation of the parasite to its intermediate hosts, evidenced by the high indexes of susceptibility, leads to different behaviour on the part of this parasite in its definitive

  3. Germline transgenesis and insertional mutagenesis in Schistosoma mansoni mediated by murine leukemia virus.

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    Gabriel Rinaldi

    Full Text Available Functional studies will facilitate characterization of role and essentiality of newly available genome sequences of the human schistosomes, Schistosoma mansoni, S. japonicum and S. haematobium. To develop transgenesis as a functional approach for these pathogens, we previously demonstrated that pseudotyped murine leukemia virus (MLV can transduce schistosomes leading to chromosomal integration of reporter transgenes and short hairpin RNA cassettes. Here we investigated vertical transmission of transgenes through the developmental cycle of S. mansoni after introducing transgenes into eggs. Although MLV infection of schistosome eggs from mouse livers was efficient in terms of snail infectivity, >10-fold higher transgene copy numbers were detected in cercariae derived from in vitro laid eggs (IVLE. After infecting snails with miracidia from eggs transduced by MLV, sequencing of genomic DNA from cercariae released from the snails also revealed the presence of transgenes, demonstrating that transgenes had been transmitted through the asexual developmental cycle, and thereby confirming germline transgenesis. High-throughput sequencing of genomic DNA from schistosome populations exposed to MLV mapped widespread and random insertion of transgenes throughout the genome, along each of the autosomes and sex chromosomes, validating the utility of this approach for insertional mutagenesis. In addition, the germline-transmitted transgene encoding neomycin phosphotransferase rescued cultured schistosomules from toxicity of the antibiotic G418, and PCR analysis of eggs resulting from sexual reproduction of the transgenic worms in mice confirmed that retroviral transgenes were transmitted to the next (F1 generation. These findings provide the first description of wide-scale, random insertional mutagenesis of chromosomes and of germline transmission of a transgene in schistosomes. Transgenic lines of schistosomes expressing antibiotic resistance could advance

  4. Metacercarial distribution of Centrocestus formosanus among fish hosts in the Guadalupe River drainage of Texas.

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    Fleming, B Paul; Huffman, David G; Bonner, Timothy H; Brandt, Thomas M

    2011-09-01

    We examined the gills of wild fish collected from central Texas for Centrocestus formosanus metacercariae to determine whether this temperature-restricted parasite had invaded the thermally dynamic Guadalupe River via an introduced population in its thermally stable tributary, the Comal River. We collected fish from three sites in the Guadalupe River near its confluence with the Comal River (upstream, at, and downstream) and one site in the Comal River. Centrocestus formosanus infected 14 of the 25 species examined (56.0%) and 171 of the individual fish (27.1%). Several of the infected fish represent new host records for the parasite, and two are listed as species of special concern by the state of Texas. Mean metacercarial intensities varied from 8 to 616 among species, and the highest recorded intensity was greater than 800 in two Guadalupe roundnose minnow Dionda nigrotaeniata. Among the 24 species examined from the Guadalupe River, 11 (45.8%) were infected with C. formosanus. Thorough surveys at the study sites yielded no living specimens of the first obligate intermediate snail host (red-rim melania Melanoides tuberculatus), which must be present to perpetuate the parasite. Thus, the infections were probably due to drifting cercariae that had been shed into the water column upstream of the study area in the Comal River. We therefore investigated spatial patterns in cercarial acquisition using caged fish to determine whether drifting cercariae were present in the water column at the study sites. Of 57 uninfected blacktail shiners Cyprinella venusta exposed to Guadalupe River water downstream from and at the confluence, 52 (91.2%) became infected with C. Formosanus metacercariae at a mean rate of 4 metacercariae/d. This finding extends the known geographic range of this invasive exotic parasite and is the first report of the life cycle being advanced in the fish assemblage of a thermally variable temperate stream in the USA.

  5. Congenital and nursing effects on the evolution of Schistosoma mansoni infection in mice

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    J. A. Lenzi

    1987-01-01

    Full Text Available Modification of the immune response to schistosomal infection in children or offspring born to mother R infected with Schistosoma mansoni has been demonstrated in human and in experimental schistosomiasis. One of the hypothesis to explain this fact could be the transfer of circulating antigens and antibodies from mother to foetus through the placenta or from mother to child by milk. The results of this spontaneous transference are controversial in the literature. In an attempt to investigate these questions, we studied one hundred and twenty offspring (Swiss mice, sixty born to infected-mothers (group A and sixty born to non-infected mothers (group B. These were percutaneously infected with 50 cercariae/mouse, and divided in six sub-groups (20 mice/sub-group, according to the following schedule: after birth (sub-groups A.I and B.I, 10 days old (sub-groups A.II and B.II and 21 days old (sub-groups A.III and B.III. After the exposure period, the young mice returned to their own mothers for nursing. Six weeks later, the mice were killed. We obtained the following results: 1 There is transference of antibody to cercariae (CAP, adult worms (SWAP and egg antigens (SEA from the infected mothers to the offspring, probably through placenta and milk; 2 Offspring born to infected mothers exhibit much less coagulative hepatic necrosis and show a lower number of eggs in the small intestine and a less intense and predominant exsudative stage of the hepatic granulomas when compared with the exsudative-productive stage of the control groups. The findings suggest that congenital and nursing factors can interfere on the development of the schistosomiasis infection, causing an hyporesponse to the eggs.

  6. Experimental evaluation of Candonocypris novaezelandiae(Crustacea:Ostracoda) in the biocontrol of Schistosomiasis mansoni transmission

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    Fouad; Yousif; Sherif; Hafez; Samia; El; Bardicy; Menerva; Tadros; Hoda; Abu; Taleb

    2013-01-01

    Objective:To test Candonocypris novaezelandiae(Baird)(C.novaezelandiae),sub-class Ostracoda,obtained from the Nile,Egypt for its predatory activity on snail,Biomphalaria alexandrina(B.alexandrina),intermediate host of Schistosoma mansoni(S.mansoni)and on the free-living larval stages of this parasite(miracidia and cercariae).Methods:The predatory activity of C.novaezelandiae was determined on B.alexandrina snail(several densities of eggs,newly hatched and juveniles).This activity was also determined on S.mansoni miracidia and cercariae using different volumes of water and different numbers of larvae.C.novaezelandiae was also tested for its effect on infection of snails and on the cercarial production.Results:C.novaezelandiae was found to feed on the eggs,newly hatched and juvenile snails,but with significant reduction in the consumption in the presence of other diet like the blue green algae(Nostoc muscorum).This ostracod also showed considerable predatory activity on the free-living larval stages of S.mansoni which was affected by certain environmental factors such as volume of water,density of C.novaezelandiae and number of larvae of the parasite.Conclusions:The presence of this ostracod in the aquatic habitat led to significant reduction of snail population,infection rate of snails with schistosme miracidia as well as of cercarial production from the infected snails.This may suggest that introducing C.novaezelandiae into the habitat at schistosome riskv sites could suppress the transmission of the disease.

  7. Effectiveness of synthetic trioxolane OZ78 against Schistosoma japonicum in mice and rabbits.

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    Xiao, Shu-Hua; Xue, Jian; Mei, Jing-Yan; Jiao, Pei-Ying

    2012-06-01

    Antischistosomal activities of a synthetic peroxide OZ78 (an ozonide carboxylic acid) against Schistosoma japonicum have been studied in mice and rabbits. Among 132 mice used, 30 of them were infected with 80-100 S. japonicum cercariae for collection of juvenile and adult schistosomes applied in in vitro tests. The remaining 102 mice were infected with 40 schistosome cercariae used for experimental treatment. Other 13 rabbits infected each with 200 schistosome cercariae were treated orally with OZ78 42 days post-infection. Most treated mice and rabbits were sacrificed 4 weeks post-treatment to collect residual schistosomes for evaluation of the drug efficacy. OZ78 and its sodium salt (OZ78-Na salt) 10-60 μg/mL alone exhibited no in vitro effect against day 14, day 21 schistosomula, and day 35 adult schistosomes. But OZ78 and OZ78-Na salt 10 and 20 μg/mL together with hemin 80 μg/mL showed decrease in worm motor activity and severe damage to the worm tegument and intestine, and all worms died within 3 days post-incubation. After infected mice were treated orally with OZ78 at a single dose of 400 mg/kg for 1 day, 34.9% of the worms shifted to the liver. Three and 7 days post-treatment, 100% of the worms were recovered from the liver. Fourteen days post-treatment, 92.3% of the worms still remained in the liver and 7.7% of the worms returned back to the mesenteric veins. Male and female worms shifted to the liver revealed in apparent shrinkage, degeneration of worm body, depigmentation in gut, and disappearance of ova in the uterus of some female worms. Meanwhile, dead worm and dead worm fragments were found in the liver tissues. In mice infected with various stages of schistosomes and treated orally with single OZ78 400 mg/kg, moderate or potential effect of the drug against day 0 (3-h-old worm), day 7, day 14, and day 21 juvenile worms and day 28, day 35 as well as day 42 adult worms were observed, the differences of total or female worm burdens between each

  8. Protective immunity induced by the anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum%日本血吸虫单克隆抗独特型抗体NP30诱导保护性免疫的研究

    Institute of Scientific and Technical Information of China (English)

    冯振卿; 李玉华; 薛婉芬; 仇镇宁; 李芸茜; 朱昌亮; 管晓虹

    2002-01-01

    Objective To investigate the protective immunity induced by the anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum in mice.Methods An orthogonal table L16(4×212) was selected as the experimental design. Eight-week-old Kunming outbred mice (male and female) were randomly divided into 16 experimental groups and 2 control groups. Control groups were injected with SP2/0 ascites intraperitoneally. Mice from each group were infected with 100±2 cercariae of Schistosoma japonicum in the abdominal skin and were sacrificed on the thirtieth day postchallenge. Adult worms were recovered and counted by perfusion of the left ventricle-portal vein. The SP2/0 ascites injected mice were used as controls and the percentage of protection was calculated.Results Active immunization of mice with NP30 could produce protection levels ranging from 22.36% to 50.46% depending on the different immunity protocols. The best immunization protocol was established from the results.Conclusions Active immunization with NP30 can induce a degree of protection to infection with Schistosoma japonicum cercariae and NP30 is a potential vaccine candidate against Schistosoma japonicum.%目的 观察日本血吸虫单克隆抗独特型抗体NP30主动免疫小鼠诱导的保护性免疫力.方法 选择L16(4×212)正交设计,8周龄昆明种小鼠随机分为16个实验组和2个对照组.对照组腹腔接种SP2/0腹水.所有小鼠在腹部皮肤感染100±2条日本血吸虫尾蚴,尾蚴攻击后第30天处死小鼠,行左心室-门静脉灌注收集成虫,计算减虫率.结果 根据不同的免疫方案,NP30主动免疫可产生22.36%-50.46%的减虫率,并确定了最优免疫方案.结论 提示NP30主动免疫对尾蚴攻击可产生一定的保护力,具有血吸虫疫苗候选分子的潜能.

  9. Estudo da potencialidade de populações de Biomphalaria straminea do Estado de Minas Gerais, como hospedeiras do Schistosoma mansoni Potentiality of the Biomphalaria straminea populations of the State of Minas Gerais, as hosts of Schistosoma mansoni

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    Cecília Pereira de Souza

    1983-09-01

    Full Text Available Caramujos de Biomphalaria straminea, descendentes de exemplares coletados em nove municípios do Estado de Minas Gerais, foram infectados experimentalmente com três cepas de Schistosoma mansoni: "LE", procedente de Belo Horizonte (MG; "SJ", procedente de São José dos Campos (SP e "AL" procedente do Nordeste (AL. As taxas de infeção variaram de 0,0 a 24,0% com a cepa "LE"; de 0,0 a 16% com a cepa "SJ" e de 2,0 a 9,0% com a cepa "AL". Os índices de infecção experimental obtidos foram semelhantes aos registrados por outros autores, para B. straminea dessa região. Comparou-se o número de cercárias de cepa "LE", eliminadas por oito exemplares de B. straminea de Baldim e oito Biomphalaria glabrata do controle, após 30 minutos de exposição à luz. O número de cercárias eliminadas por B. straminea foi de 4.550, aproximadamente cinco vezes menor que o de B. glabrata, 22.679. Discute-se a potencialidade desses moluscos como hospedeiros do S. mansoni nessa região.The decendents of Biomphalaria straminea snails collected in nine regions from the State of Minas Gerais were experimentally infected with three strains of Schistosoma mansoni: "LE", from Belo Horizonte, Minas Gerais; "SJ", from São José dos Campos, State of São Paulo and "AL", from State of Alagoas. The infection rates obtained were of 0 to 24% (LE strain, 0 to 16% (SJ strain and 2 to 9% (AL strain. These infection rates were similar to those obtained by other authors for B. straminea from this region. Comparation were made between the numbers of cercariae (LE strain shed by eight specimens of B. straminea from Baldim and eight B. glabrata of the control group, after 30 minutes of exposure to light. B. straminea shed 4,550 cercariae, about five times less than B. glabrata (22,679. The authors discuss the potentiality of theses molluscs as hosts of S. mansoni in this region.

  10. The Schistosoma mansoni tegumental-allergen-like (TAL protein family: influence of developmental expression on human IgE responses.

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    Colin M Fitzsimmons

    Full Text Available BACKGROUND: A human IgE response to Sm22.6 (a dominant IgE target in Schistosoma mansoni is associated with the development of partial immunity. Located inside the tegument, the molecule belongs to a family of proteins from parasitic platyhelminths, the Tegument-Allergen-Like proteins (TALs. In addition to containing dynein-light-chain domains, these TALs also contain EF-hand domains similar to those found in numerous EF-hand allergens. METHODOLOGY/PRINCIPAL FINDINGS: S. mansoni genome searches revealed 13 members (SmTAL1-13 within the species. Recent microarray data demonstrated they have a wide range of life-cycle transcriptional profiles. We expressed SmTAL1 (Sm22.6, SmTAL2, 3, 4, 5 and 13 as recombinant proteins and measured IgE and IgG4 in 200 infected males (7-60 years from a schistosomiasis endemic region in Uganda. For SmTAL1 and 3 (transcribed in schistosomula through adult-worms and adult-worms, respectively and SmTAL5 (transcribed in cercariae through adult-worms, detectable IgE responses were rare in 7-9 year olds, but increased with age. At all ages, IgE to SmTAL2 (expressed constitutively, was rare while anti-SmTAL2 IgG4 was common. Levels of IgE and IgG4 to SmTAL4 and 13 (transcribed predominantly in the cercariae/skin stage were all low. CONCLUSIONS: We have not measured SmTAL protein abundance or exposure in live parasites, but the antibody data suggests to us that, in endemic areas, there is priming and boosting of IgE to adult-worm SmTALs by occasional death of long-lived worms, desensitization to egg SmTALs through continuous exposure to dying eggs and low immunogenicity of larval SmTALs due to immunosuppression in the skin by the parasite. Of these, it is the gradual increase in IgE to the worm antigens that parallels age-dependent immunity seen in endemic areas.

  11. Biomass and productivity of trematode parasites in pond ecosystems.

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    Preston, Daniel L; Orlofske, Sarah A; Lambden, Jason P; Johnson, Pieter T J

    2013-05-01

    1. Ecologists often measure the biomass and productivity of organisms to understand the importance of populations and communities in the flow of energy through ecosystems. Despite the central role of such studies in the advancement of freshwater ecology, there has been little effort to incorporate parasites into studies of freshwater energy flow. This omission is particularly important considering the roles that parasites sometimes play in shaping community structure and ecosystem processes. 2. Using quantitative surveys and dissections of over 1600 aquatic invertebrate and amphibian hosts, we calculated the ecosystem-level biomass and productivity of trematode parasites alongside the biomass of free-living aquatic organisms in three freshwater ponds in California, USA. 3. Snails and amphibian larvae, which are both important intermediate trematode hosts, dominated the dry biomass of free-living organisms across ponds (snails = 3.2 g m(-2); amphibians = 3.1 g m(-2)). An average of 33.5% of mature snails were infected with one of six trematode taxa, amounting to a density of 13 infected snails m(-2) of pond substrate. Between 18% and 33% of the combined host and parasite biomass within each infected snail consisted of larval trematode tissue, which collectively accounted for 87% of the total trematode biomass within the three ponds. Mid-summer trematode dry biomass averaged 0.10 g m(-2), which was equal to or greater than that of the most abundant insect orders (coleoptera = 0.10 g m(-2), odonata = 0.08 g m(-2), hemiptera = 0.07 g m(-2) and ephemeroptera = 0.03 g m(-2)). 4. On average, each trematode taxon produced between 14 and 1660 free-swimming larvae (cercariae) infected snail(-1) 24 h(-1) in mid-summer. Given that infected snails release cercariae for 3-4 months a year, the pond trematode communities produced an average of 153 mg m(-2) yr(-1) of dry cercarial biomass (range = 70-220 mg m(-2) yr(-1)). 5. Our results suggest that a significant amount of energy

  12. In vivo and in vitro effects of the herbicide Roundup(®) on developmental stages of the trematode Echinostoma paraensei.

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    Monte, Tainá C de C; Garcia, Juberlan; Gentile, Rosana; de Vasconcellos, Maurício Carvalho; Souza, Joyce; Braga, Brunna V; Maldonado, Arnaldo

    2016-10-01

    The exposure of wildlife and humans to toxic residues of Roundup(®) through agricultural practices or the food chain has been reported since the herbicide was found contaminating rivers. Glyphosate, N-(phosphonomethyl)glycine acid, is a nonselective post-emergent herbicide and is formulated as an isopropylamine salt with the surfactant taloamine polyethoxylate (POEA) representing the commercial formulation of Roundup(®). There is little knowledge about the effects of the herbicide on helminth parasites, particularly those whose life cycle is related to water bodies. Here we investigated the effects of the Roundup(®) on the food-borne trematode Echinostoma paraensei in experimental conditions using different developmental stages (eggs, miracidia, cercariae, metacercariae, newly excysted larvae (NEL), helminths at seven days and helminths at fourteen days). Three different herbicide concentrations were tested based on concentrations typically applied in the field: 225, 450 and 900 mg/L. Specimens were analyzed in vitro for hatching miracidia, mortality and excystment rate of metacercariae and in vivo for parasitic load and egg production. There was a significant difference in the hatching miracidia rate only for the newly embryonated eggs. The mortality of specimens and excystment rate of metacercariae were concentration-dependent. There was a significant difference in the miracidia mortality with respect to concentration until 56.3 mg/L. The same effect was observed for cercariae, and mortality was observed from 15 min onwards at concentrations of 225-900 mg/L. At low concentrations, mortality was detected after 30 min. The effects of the herbicide concentration on NEL and on helminths at seven and fourteen days showed a significant difference after 24 h. There was no significant difference in parasitic load and egg production after infection of rodents with exposed metacercariae. All developmental stages of the trematode E. paraensei were affected by

  13. Compatibilidad entre nueve cepas de Biomphalaria glabrata de áreas endémicas y no endémicas y una cepa de Schistosoma mansoni venezolanas

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    Pino Luz A.

    1999-01-01

    Full Text Available Se infectaron experimentalmente 9 lotes de 32 caracoles B. glabrata (de 5 a 7mm de diámetro con miracidios de la cepa C5 de Schistosoma mansoni a razón de 5 miracidios por caracol, pertenecientes a las siguientes cepas: En el área endémica de transmisión de Esquistosomiasis mansoni a Sector Puerta Negra, Lago Valencia, b Cagua c Ingenio Bolívar (Estado Aragua d Mariara e Caserío El 25 f Güigüe (Estado Carabobo. Fuera del área endémica de transmisión g Anzoátegui (Estado Lara, h Chabasquén (Estado Portuguesa, i Sector La Elvira, Caripe (Estado Monagas. El período prepatente intramolusco, osciló entre 23 y 25 días, para las 9 cepas evaluadas. La duración total de la infección fue muy variable desde 20 días para la cepa Chabasquén, hasta 93 días para la de Güigüe.La producción total promedio de cercarias al tercer día de iniciada la emisión varió desde X = 74,4 para la cepa de Mariara, hasta X = 591,7 para la cepa de Chabasquén. Se evidenció la existencia de diferencias estadísticamente significativas (H = 97,4, P < 0,05 en la producción total de cercarias al tercer día de iniciada la emisión, detectándose diferencias estadísticamente significativas para casi todas las 36 combinaciones, excepto para las cuatro siguientes: Mariara/Ingenio Bolívar, Cagua/Caserío El 25, Lago de Valencia/Güigüe y Güigüe/Caripe.En lo que respecta al porcentaje de caracoles que presentaron cura espontánea, los valores mas elevados se obtuvieron en las cepas del Lago de Valencia (88,8%, Cagua (85,2%, Chabasquén (82,6%, Caripe (82,6% y Anzoátegui (80%. Mientras que el porcentaje mas bajo se obtuvo para la cepa de Güigüe (21,4%.

  14. Ciclo biológico de Paraibatrema inesperata n.g., n.sp. (Trematoda, Paramphistomidae, a partir de metacercárias desenvolvidas em Biomphalaria tenagophila (D'Orbigny, 1835 (Mollusca, Planorbidae

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    Marlene Tiduko Ueta

    1981-03-01

    Full Text Available Em exemplares de B. tenagophila, capturados em ambiente natural, foram encontradas paranfistomocercárias de precoce encistamento. Procedeu-se à infecção, per os, de animais de biotério; em camundongos e ratos, verificou-se o desenvolviemnto de trematóide paranfistomídeo desconhecido e que, por suas características, não se enquadra nos g~eneros conhecidos de Paramphistomidae de mamíferos. Para o parasito em apreço é proposta a denominação Paraibatema inesperata n.g, n.sp.. A partir de miracídios, oriundos de ovos eliminados pelos roedores em experiência, procurou-se infectar B. tenagophila e B. glabrata, criadas no moluscário. Verificou-se ser ativa a penetração dos miracídios no tecido do molusco, sendo freqüente a formação de tumorações nas antenas. A evolução experimental no hospedeiro intermediário apresenta-se lenta; ao fim de 40 dias de pós-infecção, não se observou a formação de esporocistos, rédias e cercárias.The new genus and new species of paramphistomid trematode, Paraibatrema inesperata n.g, n.sp., are proposed. The parasite was originally found as a quickly encysting paramphistome cercaria from specimens of the planorbid snail Biomphalaria tenagophila caught in natural habitats. Experimental infection resulted from intubation of metacercariae into the stomach of white mice and rats, which passed eggs in the feces 20 days later. Specimens of B. tenagophila and B. glabrata have been exposed to miracidia from eggs passed by mice. Penetration of the molluscan tegument was observed, but it seems that the larval development of the parasite is slow, inasmuch as no rediae and cercariae have been obtained as yet.

  15. Malacological survey and geographical distribution of vector snails for schistosomiasis within informal settlements of Kisumu City, western Kenya

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    Opisa Selpha

    2011-12-01

    Full Text Available Abstract Background Although schistosomiasis is generally considered a rural phenomenon, infections have been reported within urban settings. Based on observations of high prevalence of Schistosoma mansoni infection in schools within the informal settlements of Kisumu City, a follow-up malacological survey incorporating 81 sites within 6 informal settlements of the City was conducted to determine the presence of intermediate host snails and ascertain whether active transmission was occurring within these areas. Methods Surveyed sites were mapped using a geographical information system. Cercaria shedding was determined from snails and species of snails identified based on shell morphology. Vegetation cover and presence of algal mass at the sites was recorded, and the physico-chemical characteristics of the water including pH and temperature were determined using a pH meter with a glass electrode and a temperature probe. Results Out of 1,059 snails collected, 407 (38.4% were putatively identified as Biomphalaria sudanica, 425 (40.1% as Biomphalaria pfeifferi and 227 (21.5% as Bulinus globosus. The spatial distribution of snails was clustered, with few sites accounting for most of the snails. The highest snail abundance was recorded in Nyamasaria (543 snails followed by Nyalenda B (313 snails. As expected, the mean snail abundance was higher along the lakeshore (18 ± 12 snails compared to inland sites (dams, rivers and springs (11 ± 32 snails (F1, 79 = 38.8, P Biomphalaria snails was higher in the inland (2.7% compared to the lakeshore sites (0.3% (P = 0.0109. B. sudanica was more abundant in sites along the lakeshore whereas B. pfeifferi and B. globosus were more abundant in the inland sites. Biomphalaria and Bulinus snails were found at 16 and 11 out of the 56 inland sites, respectively. Conclusions The high abundance of Biomphalaria and Bulinus spp. as well as observation of field-caught snails shedding cercariae confirmed that besides Lake

  16. Congenital Transmission of Schistosoma japonicumin the Rabbit

    Institute of Scientific and Technical Information of China (English)

    QianBao-zhen; H.O.Bogh; M.V.Johansen; WangPeng-peng

    2005-01-01

    Fourteen pregnant rabbits were each infected with 300 cercariae of Schistosoma japonicum and divided into two groups.Group M (n =8)was infected during mid-gestation (the organogenetic stage)and group L (n=6)was infected during late-gestation (the post-organogenetic stage).Mother rabbits and rabbit kittens were killed 45-60 days after infection and perfused in order to obtain worm counts.Furthermore,faecal egg counts and tissue egg counts from livers were obtained from the mother rabbits as well as the rabbit kittens.All mother rabbits became infected harbouring 207.6+20.2 and 220.0+27.5 adult worms in group M and L,respectively.In groups M and L, 13.5%and 46.7% of the kittens were infected,respectively,In 12 of 14 litters at least one kitten was infected.Tne infected kittens harboured between one and three adult S.japonicum.The livers of the kittens infected with a worm pair displaced lesions,as a result of egg deposition.The results, therefore,show that congenital transmission of S.japonicum can occur in rabbits.The close anatomical resemblance between the rabbit and human placenta may be indicative of the presence of congenital transmssion of S.japomcum infection in humans.

  17. Morphology and life cycle of Apatemon hypseleotris species novum from Australia including metacercariae viability and excystment.

    Science.gov (United States)

    Negm-Eldin, M; Davies, R W

    2002-07-01

    Experimental infection of pigeon squabs and rats with encysted metacercariae from the Western Carp gudgeon (Hypseleotris klunzingeri) showed them to be infected with a new strigeid trematode, Apatemon hypseleotris. Growth and development of A. hypseleotris in pigeons were significantly higher than in rats. Eggs appeared in pigeon faeces within 7-14 days; miracidia hatched within 15-21 days and in the snail Lymnaea tomentosa released within 21 days. Cercariae experimentally encysted in the leeches Helobdella papillornata (86.7%) and Alboglossiphonia australiensis (73.3%). In fish, encystation occurred in the abdominal cavity (100%) and muscles (40%) of Hypseleotris klunzingeri, in the abdominal cavity (80%) and head (30%) of Gambusia affinis and in the abdominal cavity (62.5%) of Oncorhynchus mykiss but no encystation occurred in Moenkhausia pittieri. Freezing (-7 degrees C for 3-7 days or -21 degrees C for 8-12 hours), chilling (6 degrees C for 12 days), boiling (3 minutes) or salting for 3-5 days of encysted metacercariae did not significantly reduce infectivity. In vitro excystation of metacercariae was achieved using pepsin followed by trypsin and/or bile salts. PMID:12161969

  18. Expression profile of the Schistosoma japonicum degradome reveals differential protease expression patterns and potential anti-schistosomal intervention targets.

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    Shuai Liu

    2014-10-01

    Full Text Available Blood fluke proteases play pivotal roles in the processes of invasion, nutrition acquisition, immune evasion, and other host-parasite interactions. Hundreds of genes encoding putative proteases have been identified in the recently published schistosome genomes. However, the expression profiles of these proteases in Schistosoma species have not yet been systematically analyzed. We retrieved and culled the redundant protease sequences of Schistosoma japonicum, Schistosoma mansoni, Echinococcus multilocularis, and Clonorchis sinensis from public databases utilizing bioinformatic approaches. The degradomes of the four parasitic organisms and Homo sapiens were then comparatively analyzed. A total of 262 S. japonicum protease sequences were obtained and the expression profiles generated using whole-genome microarray. Four main clusters of protease genes with different expression patterns were identified: proteases up-regulated in hepatic schistosomula and adult worms, egg-specific or predominantly expressed proteases, cercaria-specific or predominantly expressed proteases, and constantly expressed proteases. A subset of protease genes with different expression patterns were further validated using real-time quantitative PCR. The present study represents the most comprehensive analysis of a degradome in Schistosoma species to date. These results provide a firm foundation for future research on the specific function(s of individual proteases and may help to refine anti-proteolytic strategies in blood flukes.

  19. Immunization of cattle against Schistosome bovis (including pathophysiological studies on schistosome infection in bovines)

    International Nuclear Information System (INIS)

    Bovine schistosomiasis caused by S. bovis constitutes a serious veterinary problem in the Sudan, yet very little is known about the epidemiology, pathogenesis and immunology of the disease. Over the past 5 years, work on these aspects has been conducted at Khartoum and several outlying areas of the White Nile Province in Sudan. In studies involving over 1,000 cattle, it was found that almost 100% of animals are infected by 2 years of age but that the prevalence falls to less than 60% over the following 7 years. There was also a marked reduction in the intensity of infection with increasing age, indicating the development of a high degree of acquired resistance. This was confirmed experimentally by challenging animals from an endemic area with massive numbers of cercariae. These animals completely resisted the challenge whereas animals never previously exposed either died or became moribund due to the severe haemorrhagic diarrhoea resulting from the passage of schistosome eggs through the gut wall. Attempts were made to vaccinate calves using irradiated organisms. These gave 70-80% protection against a challenge infection and this was sufficient to allow these animals to gain weight and remain clinically healthy. Animals not given the vaccine deteriorated. The efficacy of the vaccine was then tested under field conditions and found to give a high level of protection against S. bovis. These animals were also less susceptible to intercurrent infections

  20. Evaluation of the antischistosomal activity of sulfated α-D-glucan from the lichen Ramalina celastri free and encapsulated into liposomes

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    R.V.S. Araújo

    2011-04-01

    Full Text Available The antischistosomal activity of the sulfated polysaccharide α-D-glucan (Glu.SO4 extracted from Ramalina celastri was evaluated after encapsulation into liposomes (Glu.SO4-LIPO in Schistosoma mansoni-infected mice. The effect of treatment with Glu.SO4 and Glu.SO4-LIPO (10 mg/kg on egg elimination, worm burden and hepatic granuloma formation was assessed using female albino Swiss mice, 35-40 days of age, weighing 25 ± 2 g, infected with 150 cercariae/animal (Biomphalaria glabrata, BH strain. Four groups (N = 10 were studied, two controls (empty liposomes and NaCl and two treated groups (Glu.SO4-LIPO and Glu.SO4 using a single dose. Parasitological analysis revealed that Glu.SO4-LIPO was as efficient as Glu.SO4 in reducing egg elimination and worm burden. Treatment with free Glu.SO4 and Glu.SO4-LIPO induced a statistically significant reduction in the number of granulomas (62 and 63%, respectively. Lectin histochemistry showed that wheat germ agglutinin intensely stained the egg-granuloma system in all treated groups. On the other hand, peanut agglutinin stained cells in the control groups, but not in the treated groups. The present results suggest a correlation between the decreasing number of hepatic egg-granulomas and the glycosylation profile of the egg-granuloma system in animals treated with free Glu.SO4 or Glu.SO4-LIPO.

  1. Synthesis, Bioactivity Evaluation, and Toxicity Assessment of Novel Salicylanilide Ester Derivatives as Cercaricides against Schistosoma japonicum and Molluscicides against Oncomelania hupensis

    Science.gov (United States)

    Wang, Weisi; Qin, Zhiqiang; Zhu, Dan; Wei, Yufen; Li, Shizhu

    2015-01-01

    A series of novel salicylanilide ester derivatives were synthesized, characterized, and evaluated for cercaricidal potential against Schistosoma japonicum and molluscicidal potential against Oncomelania hupensis. Four derivatives exhibited remarkable cercaricidal activity superior to that of niclosamide. Among them, the most active compound, 4-chloro-2-((2-methoxy-4-nitrophenyl)carbamoyl)phenyl 4-methoxybenzoate (compound 4c), showed a marked minimum effective cercaricidal concentration as low as 0.43 μM and significant molluscicidal activity, with a 50% lethal concentration (LC50) of 0.206 g/m2. Particularly, compound 4c displayed 88-fold decreased fish toxicity on Danio rerio and 44-fold reduced cytotoxicity on human kidney HEK293 cells in comparison with the toxicity of niclosamide. The results indicated that 4c could serve as a promising drug candidate, with environmental safety properties, against Schistosoma japonicum at transmission stages. The preliminary molecular mechanism of target compounds in Schistosoma japonicum cercariae was also investigated. Salicylanilide ester derivatives exhibited an inhibitory effect on nitric oxide synthase (NOS) but no effect on lactate dehydrogenase (LDH) and acetylcholinesterase (AChE), and a strong and significant correlation between NOS inhibitory efficacy and cercaricidal activity was observed. In addition, 4c could downregulate the expression of NOS in a dose-dependent manner. These results suggested that NOS was probably one of the drug targets of salicylanilide esters. PMID:26503661

  2. Labelling of biological structures with technetium 99 m

    International Nuclear Information System (INIS)

    The labelling of red blood cells (RBC) with technetium 99m (99m Tc) depends on several factors, as the stannous ion (Sn++) concentration, the time and temperature of incubation, the anticoagulant utilized, the presence of plasma proteins (PP) and others. Although the blinding of 99m Tc with hemoglobin and PP are similar, they appear to have specific characteristics as demonstrated by precipitation with alcohol, acetone, trichloroacetic acid, hydrochloric acid and mercury chloride. The bacterial cultures labeled with Technetium-99m, at optimal Sn++ ion concentration, presents a large stability and their viability is not altered by this treatment. The electrophoretic mobility, the hydrophobicity, the cationized ferritin distribution and the adherence to human buccal epithelial cells are not modified either. The possibility of labelling with 99m Tc of planaria and cercariae of Schistossoma mansoni evaluative cycle increases the utilization of this radionuclide to an experimental level. The results described with the labelling of these biological structures with 99m Tc demonstrated that stable labeled and viable operations are obtained. (author)

  3. Diplostomum von Nordmann, 1832 (Digenea: Diplostomidae) in the sub-Arctic: descriptions of the larval stages of six species discovered recently in Iceland.

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    Faltýnková, Anna; Georgieva, Simona; Kostadinova, Aneta; Blasco-Costa, Isabel; Scholz, Tomáš; Skírnisson, Karl

    2014-11-01

    Frequent infections with Diplostomum spp. (Digenea: Diplostomidae) were found in the freshwater snail Radix peregra (Müller) and three fish species, the salmonids Salmo trutta fario L., Salvelinus alpinus (L.) and the gasterosteid Gasterosteus aculeatus L., collected in four lakes in south-western Iceland in 2012. Detailed analysis of the isolates integrating molecular, morphological and ecological data revealed that these belong to Diplostomum spathaceum (Rudolphi, 1819) and five putative new species (three infecting both snails and fish). This paper provides detailed descriptions of the metacercariae of the six species-level lineages of Diplostomum spp. and of the cercariae of three of the lineages discovered in Iceland with comments on the application of ITS1 rDNA for species distinction within Diplostomum von Nordmann, 1832 in the light of the novel data. We strongly suggest the use of molecular evidence based on cox1 gene sequences (in addition to ITS1-5.8S-ITS2 sequences) in association with detailed assessment of the morphology of the larval stages in future studies of Diplostomum spp. in fish and snails.

  4. New perspectives on host-parasite interplay by comparative transcriptomic and proteomic analyses of Schistosoma japonicum.

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    Feng Liu

    2006-04-01

    Full Text Available Schistosomiasis remains a serious public health problem with an estimated 200 million people infected in 76 countries. Here we isolated ~ 8,400 potential protein-encoding cDNA contigs from Schistosoma japonicum after sequencing circa 84,000 expressed sequence tags. In tandem, we undertook a high-throughput proteomics approach to characterize the protein expression profiles of a number of developmental stages (cercariae, hepatic schistosomula, female and male adults, eggs, and miracidia and tissues at the host-parasite interface (eggshell and tegument by interrogating the protein database deduced from the contigs. Comparative analysis of these transcriptomic and proteomic data, the latter including 3,260 proteins with putative identities, revealed differential expression of genes among the various developmental stages and sexes of S. japonicum and localization of putative secretory and membrane antigens, enzymes, and other gene products on the adult tegument and eggshell, many of which displayed genetic polymorphisms. Numerous S. japonicum genes exhibited high levels of identity with those of their mammalian hosts, whereas many others appeared to be conserved only across the genus Schistosoma or Phylum Platyhelminthes. These findings are expected to provide new insights into the pathophysiology of schistosomiasis and for the development of improved interventions for disease control and will facilitate a more fundamental understanding of schistosome biology, evolution, and the host-parasite interplay.

  5. BLOCKADE OF PGE2, PGD2 RECEPTORS CONFERS PROTECTION AGAINST PREPATENT SCHISTOSOMIASIS MANSONI IN MICE.

    Science.gov (United States)

    Abdel-Ghany, Rasha; Rabia, Ibrahim; El-Ahwany, Eman; Saber, Sameh; Gamal, Rasha; Nagy, Faten; Mahmoud, Olaa; Hamad, Rabab Salem; Barakat, Walled

    2015-12-01

    Schistosomiasis is a chronic disease with considerable social impact. Despite the availability of affordable chemotherapy, drug treatment has not significantly reduced the overall number of disease cases. Among other mechanisms, the parasite produces PGE2 and PGD2 to evade host immune defenses. To investigate the role of PGE2 and PGD2 in schistosomiasis, we evaluated the effects of L-161,982, Ah6809 (PGE2 receptor antagonists alone of combined with each other) and MK-0524 (PGD2 receptor antagonist) during prepatent Schistosoma mansoni infection. Drugs were administered intraperitoneally an hour before and 24 hours after infection of C57BL/6 mice with 100 Schistosoma mansoni cercariae. L-161,982, Ah6809, their combination and MK-0524 caused partial protection against pre-patent S. mansoni infection which was mediated by biasing the immune response towards Th1 phenotype. These results showed that blockade of PGE2 and PGD2 receptors confers partial protection against pre-patent S. mansoni infection in mice and that they may be useful as adjunctive therapy to current anti-schistosomal drugs or vaccines. PMID:26939228

  6. Schistosome-Derived Molecules as Modulating Actors of the Immune System and Promising Candidates to Treat Autoimmune and Inflammatory Diseases

    Science.gov (United States)

    Vieira, Anderson Rodrigues Araújo; de Campos, Tatiana Amabile

    2016-01-01

    It is long known that some parasite infections are able to modulate specific pathways of host's metabolism and immune responses. This modulation is not only important in order to understand the host-pathogen interactions and to develop treatments against the parasites themselves but also important in the development of treatments against autoimmune and inflammatory diseases. Throughout the life cycle of schistosomes the mammalian hosts are exposed to several biomolecules that are excreted/secreted from the parasite infective stage, named cercariae, from their tegument, present in adult and larval stages, and finally from their eggs. These molecules can induce the activation and modulation of innate and adaptive responses as well as enabling the evasion of the parasite from host defense mechanisms. Immunomodulatory effects of helminth infections and egg molecules are clear, as well as their ability to downregulate proinflammatory cytokines, upregulate anti-inflammatory cytokines, and drive a Th2 type of immune response. We believe that schistosomes can be used as a model to understand the potential applications of helminths and helminth-derived molecules against autoimmune and inflammatory diseases. PMID:27635405

  7. Schistosomiasis mansoni in Bananal (State of São Paulo, Brazil: II. Intermediate hosts

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    Horacio Manuel Santana Teles

    2002-10-01

    Full Text Available We conducted monthly snail captures in Bananal, State of São Paulo, Brazil, between March 1998 and February 2001, to identify Schistosoma mansoni vectors, estimate seasonal population changes, and delimit foci. We also evaluated the impact of improvements in city water supply and basic sanitation facilities. We identified 28,651 vector specimens, 28,438 as Biomphalaria tenagophila, 49 of them (0.2% infected with S. mansoni, and 213 as B. straminea, none of the latter infected. Vectors predominated in water bodies having some vegetation along their banks. Neither population density nor local vegetation could be linked to vector infection. We found the first infected snails in 1998 (from March to May. Further captures of infected snails ocurred, without exception, from July to December, when rainfall was least. Irrespective of season, overall temperature ranged from 16.5ºC to 21ºC; pH values, from 6.0 to 6.8. Neither factor was associated with snail population density. Frequent contact of people with the river result from wading across it, extracting sand from its bottom, fishing, washing animals, etc. Despite a marked reduction in contamination, cercaria shedding persists. Whatever the location along its urban course, contact with river Bananal, particularly of the unprotected skin, entails risks of infection.

  8. The effects of gamma-irradiation on migration and survival of Schistosoma mansoni schistosomula in mice

    International Nuclear Information System (INIS)

    Infections with irradiated Schistosoma mansoni were established by intramuscular injection of mechanically transformed schistosomula. A dose of 2.3 krad. allowed persistence of a small proportion of worms to adulthood, and of these survivors the majority of the female worms were sexually sterile. However, a small proportion of 2.3 krad.-irradiated females and a larger proportion of similarly irradiated males were capable of pairing successfully with non-irradiated partners. Radiation in the range 2.3 to 10 krad. resulted in slightly reduced peak recoveries from the lungs while 20 krad. resulted in a much reduced and 40 krad. a virtual absence of survival to the lung stage. Increasing doses of radiation in the range 2.3 to 10 krad. resulted in successively fewer parasites reaching the liver. Thus, the major sites of the radiation-induced mortality appeared to be 2.3 krad., mainly in the liver; 4 krad., in the lungs and liver; 10 krad., mainly in the lungs; 20 krad., at the injection site and in the lungs and 40 krad., mainly at the injection site. These infections showed reduced survival following exposure to high doses of radiation compared with the infections, established as percutaneously applied cercariae, which have been reported elsewhere. (author)

  9. The life cycle of Bucephalus margaritae Ozaki & Ishibashi, 1934 (Digenea, Bucephalidae from the coast of Santa Catarina State, Brazil - DOI: 10.4025/actascibiolsci.v32i1.5596

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    Joaber Pereira Junior

    2009-12-01

    Full Text Available The orange disease is considered the main parasitosis in Perna perna mussel. It is caused by a complex life cycle bucephalid, involving three hosts, among them mollusks and fishes. With the aim of contributing to the knowledge of orange disease in mussel culture, the parasite life cycle was investigated. Experimental studies and monthly samples in the study area allowed the identification and characterization of the Bucephalus margaritae life cycle. Larvae and adults of B. margaritae were fixed in 5% formaldehyde, stained with Gomori’s trichrome, clarified in creosote and mounted in Canada balsam. The cercariae are found in the first intermediate host P. perna inside the sporocysts, which have the form of orange and ramified filaments. The metacercariae encysts in the gills and gill cavity of the second intermediate host, the blenniid Hypleurochilus fissicornis. The definitive host Menticirrhus americanus is infected ingesting blenniids parasitized with metacercariae. The high parasitological indexes of B. margaritae suggests that M. americanus and H. fissicornis act as the main definitive and intermediate hosts, respectively, in the trematode life cycle. The blenniid H. fissicornis is a new intermediate host to the species.

  10. Schistosoma mansoni: radiation dose and morphologic integrity of schistosomules as factors for an effective cryopreserved live vaccine

    International Nuclear Information System (INIS)

    The effectiveness of a cryopreserved, irradiated schistosomule vaccine against an homologous Schistosoma mansoni cercarial challenge was tested in C57B1/6 mice. Highly significant levels of protection developed consistently when mice were immunized with the vaccine irradiated at 10-20 Krad, i.e., doses below that considered optimal for irradiated cercariae (50 Krad). Cryopreserved schistosomules irradiated at 10 or 20 Krad induced greater levels of protection than did schistosomules irradiated at 2, 5, 30, or 50 Krad. Protective immunity developed as early as 3 weeks post-immunization. When immunizing inocula were injected at various times post-thaw, or when schistosomule subpopulations of normal-appearing, damaged or dead organisms were injected, those populations which had appeared to sustain the least degree of damage were those most capable of stimulating protective immunity. These findings highlight the hazards of extrapolating conditions considered standard for an irradiated cercarial vaccine to one in which cryopreservation, for storage of the schistosomules, is an added stress

  11. Schistosoma mansoni: vaccination of mice with 10-krad-irradiated, cryopreserved schistosomules

    International Nuclear Information System (INIS)

    Protection against a Schistosoma mansoni cercarial challenge was evaluated in mice immunized with a vaccine composed of 10-krad-irradiated, cryopreserved schistosomules. The level of resistance induced in C57B1/6 or NMRI (CV) mice increased with the number of schistosomules injected. Up to 83% reduction in challenge worm burden was achieved when 5000 schistosomules were injected per mouse. Intramuscular injection of the vaccine was superior to subcutaneous. Multiple immunizations, up to 3 at 4-week intervals, did not increase the resistance induced by a single immunization. A high level of protection developed in as little as 2 weeks and was maintained through at least 12 weeks postimmunization. The vaccine irradiated with 10 krad from either a 60-cobalt or 137-cesium source induced equivalent levels of resistance, and no differences were found in the immunogenicity of vaccines comprised of organisms irradiated as cercariae or as 1- to 3-hr-old schistosomules. These findings are basic to the development of a cryopreserved, live vaccine against schistosomiasis of humans or domestic animals

  12. Differential tolerances to ocean acidification by parasites that share the same host.

    Science.gov (United States)

    MacLeod, C D; Poulin, R

    2015-06-01

    Ocean acidification is predicted to cause major changes in marine ecosystem structure and function over the next century, as species-specific tolerances to acidified seawater may alter previously stable relationships between coexisting organisms. Such differential tolerances could affect marine host-parasite associations, as either host or parasite may prove more susceptible to the stressors associated with ocean acidification. Despite their important role in many ecological processes, parasites have not been studied in the context of ocean acidification. We tested the effects of low pH seawater on the cercariae and, where possible, the metacercariae of four species of marine trematode parasite. Acidified seawater (pH 7.6 and 7.4, 12.5 °C) caused a 40-60% reduction in cercarial longevity and a 0-78% reduction in metacercarial survival. However, the reduction in longevity and survival varied distinctly between parasite taxa, indicating that the effects of reduced pH may be species-specific. These results suggest that ocean acidification has the potential to reduce the transmission success of many trematode species, decrease parasite abundance and alter the fundamental regulatory role of multi-host parasites in marine ecosystems.

  13. Esquistossomose mansônica: II - evolução dos níveis de proteínas séricas e do perfil eletroforético por técnicas de imunoeletroforese quantitativa Schistosomiasis mansoni: II - evolution of the levels of serum proteins and of their electrophoretic pattern as traced by quantitative immunoelectrophoresis

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    Ajax Mercês Atta

    1981-04-01

    Full Text Available Camundongos Swiss foram infectados com 100 cercárias da linhagem mineira (BH do Schistosoma mansoni e sacrificados semanalmente no período de 8 semanas de infecção. Os níveis de proteínas séricas totais destes animais não diferiram dos apresentados pelos animais controles. Os níveis de albumina sérica determinados por "Rocket immunoelectrophoresis" acharam-se diminuídos nas 5.ª, 6.ª e 7.ª semanas de infecção. O perfil obtido por imunoeletroforese cruzada revelou alterações em componentes séricos com mobilidade nas regiões de gama, beta e em menor grau de alfa-globulinas, após a oviposição do parasito.Swiss mice were infected with 100 cercariae of the Belo Horizonte strain of Schistosoma mansoni and were sacrificed weekly during eight weeks following of infection. The levels of serum protein totals in these animals did not differ from those presented by the control animals. However, serum albumin levels that were determined by rocket immunoelectrophoresis were lower during the 5th, 6th, and 7th weeks of infection. The pattern determined by crosed immunoelectrophoresis revealed alterations in serum components with mobility in the gamma and beta regions and, to a lesser degree, alpha-globulins, after oviposition by the parasite.

  14. Parasitological characteristics of Schistosoma mansoni infection in swiss mice with underlying malnutrition

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    Simões Carla

    2002-01-01

    Full Text Available The effects of a protein-restricted diet (8% protein, 81% carbohydrate and 11% lipids on Schistosoma mansoni infectivity, fecal egg excretion and intestinal egg distribution in Swiss (SW mice were studied. Pregnant mice received a deficient diet from the middle of gestation until delivery. Seven-days-old mice were exposed to 50 cercariae (BH strain, Brazil. Offspring mice had a free access to the deficient diet since lactation until adulthood. The controls were fed with a commercial mice diet. A parasitological examination was performed between six and eight weeks post-infection while both groups were necropsied one week later. Mice on the experimental diet showed a significant loss in body weight. There was no significant difference (p > 0.05 in pre-patent period, kinetics of egg excretion and worm recovery from mice on either diet. Significant differences (p < 0.05 were found concerning to the percentage of deposited eggs in the distal segment of the small intestine from hosts on the experimental diet.Our data suggest that experimental malnutrition induced for a long term has no detrimental effect on the acute schistosomiais infection in SW mice.

  15. On the origin of the Biomphalaria glabrata hemocytes

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    Samaly dos Santos Souza

    2006-10-01

    Full Text Available A histologic, morphometric and ultrastructural study performed on Biomphalaria glabrata submitted to infection with Schistosoma mansoni miracidia failed to provide significant evidences that the so-called amebocyte-producing organ (APO is really the central organ for hemocyte production. In infected snails no general reactive changes appeared in the APO, the mitoses were seen only occasionally, and the possibility of cellular hyperplasia was ruled out by morphometric measurements. Under the electron microscope the APO cells presented an essentially epithelial structure, without features indicative of transition toward hemocytes. On the other hand, the present findings pointed to a multicentric origin for the mollusck hemocytes, as earlier studies had indicated. Dense foci of hemocyte collections appeared sometimes around disintegrating sporocysts and cercariae in several organs and tissues of the infected snails, including a curious accumulation of such cells inside the ventricular cavity of the heart. In the heart and other sites, features suggestive of transformation of vascular space endothelial lining cells into hemocytes were apparent. To some extent, the postulated multicentric origin for B. glabrata hemocytes recapitulates earlier embryologic findings in vertebrates, when mesenchymal vascular spaces generate the circulating and phagocytic blood cells.

  16. Preliminary analysis of miRNA pathway in Schistosoma mansoni.

    Science.gov (United States)

    Gomes, Matheus S; Cabral, Fernanda J; Jannotti-Passos, Liana K; Carvalho, Omar; Rodrigues, Vanderlei; Baba, Elio H; Sá, Renata G

    2009-03-01

    RNA silencing refers to a series of nuclear and cytoplasmatic processes involved in the post-transcriptional regulation of gene expression or post-transcriptional gene silencing (PTGS), either by sequence-specific mRNA degradation or by translational arrest. The best characterized small RNAs are microRNAs (miRNAs), which predominantly perform gene silencing through post-transcriptional mechanisms. In this work we used bioinformatic approaches to identify the parasitic trematode Schistosoma mansoni sequences that are similar to enzymes involved in the post-transcriptional gene silencing mediated by miRNA pathway. We used amino acid sequences of well-known proteins involved in the miRNA pathway against S. mansoni genome and transcriptome databases identifying a total of 13 putative proteins in the parasite. In addition, the transcript levels of SmDicer1 and SmAgo2/3/4 were identified by qRT-PCR using cercariae, adult worms, eggs and in vitro cultivated schistosomula. Our results showed that the SmDicer1 and SmAgo2/3/4 are differentially expressed during schistosomula development, suggesting that the miRNA pathway is regulated at the transcript level and therefore may control gene expression during the life cycle of S. mansoni.

  17. A cyclohexanecarboxamide derivative with inhibitory effects on Schistosoma mansoni cercarial serine protease and penetration of mice skin by the parasite.

    Science.gov (United States)

    Bahgat, Mahmoud; Aboul-Enein, Mohamed N; El Azzouny, Aida A; Maghraby, Amany; Ruppel, Andreas; Soliman, Wael M

    2009-01-01

    A cyclohexanecarboxamide derivative, N-phenyl-N-[1-(piperidine-1-carbonyl)cyclohexyl] benzamide (MNRC-5), was evaluated for its inhibitory effects on Schistosoma mansoni cercarial serine protease activity and cercarial penetration. MNRC-5 exerted an inhibitory effect on S. mansoni cercarial serine protease at serial concentrations of the specific chromogenic substrate Boc-Val-Leu-Gly-Arg-PNA for such enzyme family and the inhibitory coefficient (Ki) value was deduced. Moreover, topical treatment of mice tails with the most potent inhibitory concentration of MNRC-5 formulated in jojoba oil successfully blocked cercarial penetration as demonstrated by a significant reduction (75%; p jojoba oil base containing no MNRC-5. In addition, the IgM and IgG reactivities to crude S. mansoni cercarial, worm and egg antigens were generally lower in sera from treated infected mice than untreated infected mice. In conclusion, we report on a new serine protease inhibitor capable for blocking penetration of host skin by S. mansoni cercariae as measured by lowering worm burden and decrease in the levels of both IgM and IgG towards different bilharzial antigens upon topical treatment.

  18. The effects of drugs, ions, and poly-l-lysine on the excretory system of Schistosoma mansoni

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    JR Kusel

    2006-10-01

    Full Text Available We have been able to label the excretory system of cercariae and all forms of schistosomula, immature and adult worms with the highly fluorescent dye resorufin. We have shown that the accumulation of the resorufin into the excretory tubules and collecting ducts of the male adult worm depends on the presence of extracellular calcium and phosphate ions. In the adult male worms, praziquantel (PZQ prevents this accumulation in RPMI medium and disperses resorufin from tubules which have been prelabelled. Female worms and all other developmental stages are much less affected either by the presence of calcium and phosphate ions, or the disruption caused by PZQ. The male can inhibit the excretory system in paired female. Fluorescent PZQ localises in the posterior gut (intestine region of the male adult worm, but not in the excretory system, except for the anionic carboxy fluorescein derivative of PZQ, which may be excreted by this route. All stages of the parasite can recover from damage by PZQ treatment in vitro. The excretory system is highly sensitive to damage to the surface membrane and may be involved in vesicle movement and damage repair processes. In vivo the adult parasite does not recover from PZQ treatment, but what is inhibiting recovery is unknown, but likely to be related to immune effector molecules.

  19. Immunological and parasitological parameters in Schistosoma mansoni-infected mice treated with crude extract from the leaves of Mentha x piperita L.

    Science.gov (United States)

    Dejani, Naiara N; Souza, Laís C; Oliveira, Sandra R P; Neris, Débora M; Rodolpho, Joice M A; Correia, Ricardo O; Rodrigues, Vanderlei; Sacramento, Luis V S; Faccioli, Lúcia H; Afonso, Ana; Anibal, Fernanda F

    2014-08-01

    Schistosomiasis is a chronic disease caused by an intravascular trematode of the genus Schistosoma. Praziquantel is the drug used for treatment of schistosomiasis; nevertheless failure of treatment has been reported. Consequently, the identification of new effective schistosomicidal compounds is essential to ensure the effective control of schistosomiasis in the future. In this work we investigated the immunomodulatory and antiparasitic effects of the crude leaves extract of Mentha x piperita L. (peppermint) on murine Schistosomiasis mansoni. Female Balb/c mice were infected each with 50 S. mansoni cercariae and divided into three experimental groups: (I) untreated; (II) treated daily with M. x piperita L. (100mg/kg) and III) treated on 1/42/43 days post-infection with Praziquantel (500mg/kg). Another group with uninfected and untreated mice was used as a control. Subsequently, seven weeks post-infection, S. mansoni eggs were counted in the feces, liver and intestine. Worms were recovered by perfusion of the hepatic portal system and counted. Sera levels of IL-10, IL-5, IL-13, IFN-γ, IgG1, IgE and IgG2a were assayed by ELISA. Animals treated with a daily dose of M. x piperita L. showed increased sera levels of IL-10, IFN-γ, IgG2a and IgE. Besides, M. x piperita L. treatment promoted reduction in parasite burden by 35.2% and significant decrease in egg counts in the feces and intestine.

  20. Three-dimensional structure of a schistosome serpin revealing an unusual configuration of the helical subdomain

    Energy Technology Data Exchange (ETDEWEB)

    Granzin, Joachim [Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich (Germany); Huang, Ying; Topbas, Celalettin [Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Huang, Wenying [Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Wu, Zhiping [Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Misra, Saurav [Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Hazen, Stanley L. [Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Blanton, Ronald E. [Department of Infectious Diseases, Case Western Reserve University, Cleveland, OH 44190 (United States); Lee, Xavier [Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 (United States); Weiergräber, Oliver H., E-mail: o.h.weiergraeber@fz-juelich.de [Institute of Complex Systems, ICS-6: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2012-06-01

    The crystal structure of ShSPI, a serpin from the blood fluke S. haematobium, reveals some peculiar features of the helical subdomain which have not been observed previously in the serpin superfamily. Parasitic organisms are constantly challenged by the defence mechanisms of their respective hosts, which often depend on serine protease activities. Consequently, protease inhibitors such as those belonging to the serpin superfamily have emerged as protective elements that support the survival of the parasites. This report describes the crystal structure of ShSPI, a serpin from the trematode Schistosoma haematobium. The protein is exposed on the surface of invading cercaria as well as of adult worms, suggesting its involvement in the parasite–host interaction. While generally conforming to the well established serpin fold, the structure reveals several distinctive features, mostly concerning the helical subdomain of the protein. It is proposed that these peculiarities are related to the unique biological properties of a small serpin subfamily which is conserved among pathogenic schistosomes.

  1. Taurine drinking ameliorates hepatic granuloma and fibrosis in mice infected with Schistosoma japonicum

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    Yan-Rong Yu

    2016-04-01

    Full Text Available In schistosomiasis, egg-induced hepatic granuloma formation is a cytokine-mediated, predominantly CD4+ Th2 immune response that can give rise to hepatic fibrosis. Hepatic fibrosis is the main cause of increased morbidity and mortality in humans with schistosome infection. Taurine has various physiological functions and hepatoprotective properties as well as anti-inflammatory and immunomodulatory activity. However, little is known about the role of taurine in schistosome egg-induced granuloma formation and fibrosis. We aimed to evaluate the therapeutic potential of taurine as preventative treatment for Schistosoma japonicum infection. Mice infected with S. japonicum cercariae were supplied with taurine drinking water (1% w/v for 4 weeks starting at 4 weeks post-infection. Taurine supplementation significantly improved the liver pathologic findings, reduced the serum levels of aminotransferases and area of hepatic granuloma, and prevented fibrosis progression. In addition, taurine decreased the expression of the granulomatous and fibrogenic mediators transforming growth factor β1, tumor necrosis factor α, monocyte chemotactic protein 1α and macrophage inflammatory protein 1α as well as the endoplasmic reticulum stress marker glucose-regulated protein 78. Thus, taurine can significantly attenuate S. japonicum egg-induced hepatic granuloma and fibrosis, which may depend in part on the downregulation of some relevant cytokine/chemokines and reducing the endoplasmic reticulum stress response.

  2. The life cycle of Mesostephanus indicum Mehra, 1947 (Digenea: Cyathocotylidae).

    Science.gov (United States)

    Sheena, P; Manjula, K T; Subair, K T; Janardanan, K P

    2007-09-01

    The life cycle of the cyathocotylid fluke, Mesostephanus indicum Mehra, 1947 infecting the pariah kite, Milvus migrans govinda (Accipitridae), is elucidated. The species, reported by Mehra (Proc Nat Acad Sci India 17:1-52, 1947) from Buteo rufinus rufinus (Accipitridae), was transferred to the genus Prohemistomum by Dubois (Rev Suiss de Zool 58:639-691, 1951). However, it is retained in the genus Mesostephanus because of the presence of vaginal sphincter and caudal appendage, which are the characters of the genus. Its first intermediate host is the gastropod snail, Bellamya bengalensis (Viviparidae), which released the furcocercous cercariae. The prohemistomulum-type metacercariae encysted in the muscle tissues of the freshwater fish Rasbora daniconius and Puntius sophore (Cyprinidae), Mystus malabaricus (Bagridae), Heteropneustes fossilis (Heteropneustidae), Aplocheilus lineatus (Cyprinodontidae), Etroplus maculatus and E. suratensis (Cichlidae), and Pseudosphromenus cupanus (Belontidae). Recovery of M. indicum from M. m. govinda forms a new host record, and this is the first report of the life cycle of the genus from India. PMID:17514481

  3. Digenean parasites of the marine gastropodsLittorina littorea andGibbula umbilicalis in the Northern Portuguese Atlantic coast, with a review of digeneans infecting the two gastropod genera

    Institute of Scientific and Technical Information of China (English)

    Graa Costa; Snia Soares; Fernando Carvalho; Joo Bela

    2016-01-01

    Objective:To study the digenean parasites of the prosobranch gastropods,Littorina littorea(L. littorea) andGibbula umbilicalis (G. umbilicalis) from rocky shores of the Northern Atlantic coast of Portugal. Methods: A total of 413L. littorea and 2 603G. umbilicalis were collected from rocky shores, at Aveiro estuary, Aguda Beach, and Foz Beach at Porto (Northern Atlantic coast of Portugal) from January to July 2014 and February 2014 to January 2015, respectively. Gonads and digestive glands of the gastropods were examined under light microscopy for the presence of digeneans. Infected gonads ofL. littorea were prepared for histological observation, whereas digeneans found in G. umbilicalis were studied and identified with the aid of light and scanning electron microscopy. Results: Two species of digeneans were found infecting the digestive gland and gonads of G. umbilicalis, namely,Cainocreadium labracis andLecithochirium furcolabiatum with a combined prevalence of 3%. Histological observations of gonads ofL. littorearevealed the infection with digeneans, with considerable replacement of gonadal tissues. These digeneans were not identified to species level. The prevalence of digeneans in this snail host was 0.7%. Conclusions: The present study addsG. umbilicalis as another first intermediate host for Cainocreadium labracis and extends its geographical range to the Portuguese Atlantic coast. Cercariae ofLecithochirium furcolabiatum were previously reported fromG. umbilicalis. A literature review of digeneans occurring in the gastropod generaGibbulaandLittorina is given.

  4. Melanoides tuberculata (Mollusca: Thiaridae as an intermediate host of Centrocestus formosanus (Trematoda: Heterophyidae in Brazil Melanoides tuberculata (Mollusca: Thiaridae como hospedeiro intermediário de Centrocestus formosanus (Trematoda: Heterophyidae no Brasil

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    Hudson Alves Pinto

    2010-08-01

    Full Text Available Pleurolophocercous cercariae emerged from naturally infected Melanoides tuberculata from Minas Gerais State, Brazil, were used to perform experimental infection of laboratory-reared Poecilia reticulata. Mature metacercariae were obtained from the gills of fishes and force-fed to Mus musculus. The adult parasites which recovered from small intestines of mice were identified as Centrocestus formosanus. This is the first report of M. tuberculata as intermediate host of this heterophyid in Brazil.Cercárias do tipo pleurolofocerca emergidas de Melanoides tuberculata naturalmente infectados coletados na represa da Pampulha, Belo Horizonte, Minas Gerais, Brasil, foram utilizadas para a infecção experimental de Poecilia reticulata criados em laboratório. Metacercárias maduras foram obtidas nas brânquias dos peixes e administradas por via oral a Mus musculus. Parasitos adultos recuperados no intestino delgado dos camundongos foram identificados como Centrocestus formosanus. Este é o primeiro relato de M. tuberculata como hospedeiro intermediário deste parasito no Brasil.

  5. The life cycle of Asymphylodora perccotti sp. n. (Trematoda: Lissorchiidae) in the Russian Southern Far East.

    Science.gov (United States)

    Besprozvannykh, Vladimir V; Ermolenko, Alexey V; Atopkin, Dmitry M

    2012-06-01

    Specimens of Asymphylodora perccotti sp. n. (Trematoda: Lissorchidae) were found in the esophagus of the freshwater fish Perccottus glenii (Odobantidae) taken from the Bolshaya Ussurka River Basin (Primorsky Region, Russian Southern Far East). The first intermediate host of this trematode is a gastropod, Parafossarulus manchouricus, and the secondary hosts are the same mollusk and Boreoelona ussuriensis. Specimens of the new species are similar to A. amnicolae identified by Stunkard in 1959, but the mature worms have larger suckers and shorter ceca. The cercariae of these species are distinguished by body, suckers and pharynx size. These organs in A. perccotti sp. n. are more than one-third larger than what is observed in A. amnicolae. In addition, the new species lacks the capacity for progenesis. Finally, the new species is unusual in that it resides in the fish esophagus instead of the intestine, as is common for most Asymphylodora species. Partial ribosomal DNA sequences and phylogenetic reconstruction sequence data indicate that these worms represent a new digenean species. PMID:22037488

  6. Cloning and Molecular Characterization of the Schistosoma mansoni Genes RbAp48 and Histone H4

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    Patrícia P Souza

    2002-10-01

    Full Text Available The human nuclear protein RbAp48 is a member of the tryptophan/aspartate (WD repeat family, which binds to the retinoblastoma (Rb protein. It also corresponds to the smallest subunit of the chromatin assembly factor and is able to bind to the helix 1 of histone H4, taking it to the DNA in replication. A cDNA homologous to the human gene RbAp48 was isolated from a Schistosoma mansoni adult worm library and named SmRbAp48. The full length sequence of SmRbAp48 cDNA is 1036 bp long, encoding a protein of 308 amino acids. The transcript of SmRbAp48 was detected in egg, cercariae and schistosomulum stages. The protein shows 84% similarity with the human RbAp48, possessing four WD repeats on its C-terminus. A hypothetical tridimensional structure for the SmRbAp48 C-terminal domain was constructed by computational molecular modeling using the b-subunit of the G protein as a model. To further verify a possible interaction between SmRbAp48 and S. mansoni histone H4, the histone H4 gene was amplified from adult worm genomic DNA using degenerated primers. The gene fragment of SmH4 is 294 bp long, encoding a protein of 98 amino acids which is 100% identical to histone H4 from Drosophila melanogaster.

  7. [Schistosomiasis in an ecotourism area in Minas Gerais State, Brazil].

    Science.gov (United States)

    Massara, Cristiano Lara; Amaral, Graciela Larissa; Caldeira, Roberta Lima; Drummond, Sandra Costa; Enk, Martin Johannes; Carvalho, Omar dos Santos

    2008-07-01

    This paper discusses schistosomiasis transmission in São José da Serra, a village with a population of 500 in the county of Jaboticatubas, Minas Gerais State, Brazil. The area receives thousands of visitors a year for ecotourism. The study was motivated by a case of acute schistosomiasis involving a couple that spent the 2007 Carnival (Mardi Gras) holiday in the area. Stool tests from 268 local residents (53.6% of the population) showed that 35 (13%) were positive for the infection. A comparison with a previous survey (2005) in the same location showed an increase in the schistosomiasis-positive rate from 9.6% to 12.5%, among the 56 individuals who participated in both surveys. A malacological survey of 65 Biomphalaria glabrata snails showed one specimen (1.5%) eliminating cercariae. In a similar survey in 2005, no positive snail specimens were found. The study indicates that active schistosomiasis transmission is occurring in the area, and that integrated educational programs are needed for both the local community and tourists.

  8. PENULARAN SCHISTOSOMIASIS DI DESA DODOLO DAN MEKARSARI DATARAN TINGGI NAPU SULAWESI TENGAH

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    Rosmini Rosmini

    2012-09-01

    Full Text Available The transmission of schistosomiasis is still ongoing in Dodolo and Mekarsari Villages ofNapu highland, Poso District. The people who infected with Schistosoma japonicum, intermediate host. Oncomelania hnpensis lindoensis snails that infected by cercaria. infective stage of S. japonicum and reservoir host, rats, which infected by S. japonicum were still (bund. The purpose of this study was to identify the transmission of schistosomiasis at Dodolo and Mekarsari Villages, Napu highland. The epidemiological investigation was analyzed using observational study with cross sectional design. Data collections were conducted, including stool, snail and rat suryeys. Stool samples were examined by the Kato-Katz method and rats were dissected to identify the prevalence rate of schistosomiasis in human and rats. Snails were examined using crushing method to identify the infection rate of the snails. Prevalence rate of schistosomiasis in human, rats (Rattus exulans and infection rate O. hnpensis lindoensis snails in Dodolo were 6,9%, 8,3%, 2,8% and in Mekarsari were 6,1%, 10% 2,6% respectively. Prevalence of schistosomiasis in Dodolo and Mekarsari villages is still high, so we need continuous surveillance.   Keywords: Schistosomiasis, Schistosoma japonicum, O. hupensis lindoensis, Dodolo, Mekarsari

  9. Optimization of metacercarial production for three digenean species by the use of petri dishes for raising lettuce-fed Galba truncatula.

    Science.gov (United States)

    Rondelaud, D; Fousi, M; Vignoles, P; Moncef, M; Dreyfuss, G

    2007-03-01

    Experimental infections of Galba truncatula with Fasciola hepatica, Fascioloides magna, or Paramphistomum daubneyi were carried out at 20 degrees C to determine if the use of 14-cm petri dishes for breeding lettuce-fed snails enhanced the characteristics of snail infections. Compared to infected snails raised in boxes up to day 30 post-exposure and later in individual 35-mm dishes, the survival of G. truncatula kept in 14-cm dishes and the shell height of cercariae-shedding snails during the first 45 days were higher, whatever the digenean species is. The consequence of such enhanced characteristics was a greater production of metacercariae in the case of F. hepatica (1.7 to 5.6 times higher) and P. daubneyi (2.3 times). In contrast, metacercariae of F. magna were few in number, whatever the method of snail breeding is, and this might be explained by a still incomplete adaptation between the parasite of Czech origin and the French population of G. truncatula. The use of these 14-cm dishes reduced the time necessary for snail maintenance and metacercaria collection, thus allowing a decrease in the cost price of these larvae for commercial production. PMID:17061111

  10. First molecular identification of Australapatemon burti (Miller, 1923) (Trematoda: Digenea: Strigeidae) from an intermediate host Radix labiata (Rossmaessler) (Gastropoda: Lymnaeidae) in Europe.

    Science.gov (United States)

    Aksenova, Olga V; Bespalaya, Yulia V; Bolotov, Ivan N; Kondakov, Alexander V; Sokolova, Svetlana E

    2016-01-01

    The strigeid digenean species Australapatemon burti (Miller, 1923) (Trematoda: Digenea: Strigeidae) was originally described from North America, but recorded in the Neotropical region (Drago et al. 2007; Hernández-Mena et al. 2014; Blasco-Costa et al. 2016) and in Central Europe (Faltýnková et al. 2007). In Europe, this species is rare, and there is not much information about its range (Faltýnková et al. 2007; Soldánová et al. 2012). Australapatemon burti has a complex life cycle with three larval stages, two of which (sporocyst and cercaria) use several species of freshwater snails, and the third stage (metacercaria) use non-specific host hirudineans (Dubois 1968; Davies & Ostrowski de Núñez 2012; Blasco-Costa et al. 2016). Adult flukes are parasitic in the intenstines of various waterfowl species, such as ducks and swans (Drago et al. 2007; Hernández-Mena et al. 2014). Currently, the molecular data on this parasite species includes only nucleotide sequences of four adult specimens from Mexico (Hernández-Mena et al. 2014). Their hosts were Mexican duck, Anas diazi Ridgway, American Wigeon, Anas americana Gmelin, Cinnamon Teal, Anas cyanoptera Vieillot, and Ruddy Duck, Oxyura jamaicensis (Gmelin) (Anserformes: Anatidae). PMID:27395696

  11. Habitat and host specificity of trematode metacercariae in fiddler crabs from mangrove habitats in Florida.

    Science.gov (United States)

    Smith, Nancy F; Ruiz, Gregory M; Reed, Sherry A

    2007-10-01

    Fiddler crabs (Uca spp.) are common inhabitants of temperate and tropical coastal communities throughout the world, often occupying specific microenvironments within mangrove and salt marsh habitats. As second intermediate hosts for trematodes, we investigated patterns of host distribution and parasitism for 3 species of sympatric fiddler crabs in mangrove habitats adjacent to the Indian River Lagoon, Florida. Fiddler crab distribution varied among species, with Uca speciosa dominating the low and mid intertidal regions of mangrove banks. This species also exhibited higher prevalence and abundance of Probolocoryphe lanceolata metacercariae compared with Uca rapax, which is relatively more abundant in the high intertidal zone. We conducted a field experiment to test whether U. speciosa was more heavily parasitized by P. lanceolata as a result of its habitat distribution by raising U. speciosa and U. rapax under identical environmental conditions. After exposure to shedding cercariae under the same field conditions, all individuals of U. speciosa became parasitized by P. lanceolata, whereas no U. rapax were parasitized, suggesting that differences in parasitism were driven by host selection. PMID:18163332

  12. Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

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    Ana Lisa do Vale Gomes

    2006-10-01

    Full Text Available This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA. The efficiency was 0.99 and the correlation coefficient (R² was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83ºC. The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

  13. Chromatographic Fingerprint Analysis and Effects of the Medicinal Plant Species Mitracarpus frigidus on Adult Schistosoma mansoni Worms

    Science.gov (United States)

    Fabri, Rodrigo Luiz; Aragão, Danielle Maria de Oliveira; Florêncio, Jônatas Rodrigues; Pinto, Nícolas de Castro Campos; Mattos, Ana Carolina Alves; Coelho, Paulo Marcos Zech; Castañon, Maria Christina Marques Nogueira; Vasconcelos, Eveline Gomes; Pinto, Priscila de Faria; Scio, Elita

    2014-01-01

    The aims of this work were to evaluate the in vitro and in vivo schistosomicidal properties of the methanolic extract of the aerial parts of Mitracarpus frigidus (MFM) and to determine its HPLC profile. For the in vitro experiment, four pairs of adult worms, obtained from infected mice, were exposed to different concentrations of MFM (100 to 400 μg/mL) for 24 and 48 h and analyzed under an inverted microscope. For the in vivo experiment, mice were inoculated with cercariae and, 20 days after infection, MFM (100 and 300 mg/kg) was administered orally for the following 25 days. Mice were euthanized after 60 days. MFM showed in vitro schistosomicidal activity, exhibiting the opening of the gynaecophoral canal of some male schistosomes, the presence of contorted muscles, vesicles, and the darkening of the paired worms skin. In vivo experiments showed that MFM treatments significantly reduced total worm count, as praziquantel, showing a decrease in liver and spleen weight. Also, a significant reduction in granuloma density was observed. MFM treatment did not cause alterations in the liver function of either infected or noninfected mice. The HPLC chromatogram profile showed the presence of kaempferol-O-rutinoside, rutin, kaempferol, psychorubrin, and ursolic acid. PMID:24901000

  14. Chromatographic Fingerprint Analysis and Effects of the Medicinal Plant Species Mitracarpus frigidus on Adult Schistosoma mansoni Worms

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    Rodrigo Luiz Fabri

    2014-01-01

    Full Text Available The aims of this work were to evaluate the in vitro and in vivo schistosomicidal properties of the methanolic extract of the aerial parts of Mitracarpus frigidus (MFM and to determine its HPLC profile. For the in vitro experiment, four pairs of adult worms, obtained from infected mice, were exposed to different concentrations of MFM (100 to 400 μg/mL for 24 and 48 h and analyzed under an inverted microscope. For the in vivo experiment, mice were inoculated with cercariae and, 20 days after infection, MFM (100 and 300 mg/kg was administered orally for the following 25 days. Mice were euthanized after 60 days. MFM showed in vitro schistosomicidal activity, exhibiting the opening of the gynaecophoral canal of some male schistosomes, the presence of contorted muscles, vesicles, and the darkening of the paired worms skin. In vivo experiments showed that MFM treatments significantly reduced total worm count, as praziquantel, showing a decrease in liver and spleen weight. Also, a significant reduction in granuloma density was observed. MFM treatment did not cause alterations in the liver function of either infected or noninfected mice. The HPLC chromatogram profile showed the presence of kaempferol-O-rutinoside, rutin, kaempferol, psychorubrin, and ursolic acid.

  15. An overview of freshwater snails in Asia with main focus on Vietnam.

    Science.gov (United States)

    Madsen, H; Hung, N M

    2014-12-01

    Freshwater snails have received much attention for their role as intermediate hosts for trematodes causing disease in people and animals such as schistosomiasis and various food-borne trematodes. While effective medical treatment exists for some of these diseases there is need for preventive measures to reduce transmission, e.g. control of intermediate hosts because transmission patterns are often complicated due to presence of reservoir final hosts. In order to implement control measures against the intermediate host snails with minimal impact on the freshwater ecosystems and their biodiversity, a profound knowledge on transmission patterns of the trematodes is required and this is partly related to distribution, habitat preferences, and seasonal variation in density of the intermediate host species. Identification of snail species can be problematic on the basis of morphological and anatomical characters alone as some species show morphological plasticity and similarly morphological differentiation of cercariae found in snails may be difficult and this could lead to biased perceptions of intermediate host spectra and transmission patterns. In this paper, we give an overview of the snail families and their medical and veterinary importance in Asia but with main focus on Vietnam. PMID:25149356

  16. Reprint of "An overview of freshwater snails in Asia with main focus on Vietnam".

    Science.gov (United States)

    Madsen, H; Hung, N M

    2015-01-01

    Freshwater snails have received much attention for their role as intermediate hosts for trematodes causing disease in people and animals such as schistosomiasis and various food-borne trematodes. While effective medical treatment exists for some of these diseases there is need for preventive measures to reduce transmission, e.g. control of intermediate hosts because transmission patterns are often complicated due to presence of reservoir final hosts. In order to implement control measures against the intermediate host snails with minimal impact on the freshwater ecosystems and their biodiversity, a profound knowledge on transmission patterns of the trematodes is required and this is partly related to distribution, habitat preferences, and seasonal variation in density of the intermediate host species. Identification of snail species can be problematic on the basis of morphological and anatomical characters alone as some species show morphological plasticity and similarly morphological differentiation of cercariae found in snails may be difficult and this could lead to biased perceptions of intermediate host spectra and transmission patterns. In this paper, we give an overview of the snail families and their medical and veterinary importance in Asia but with main focus on Vietnam. PMID:25446169

  17. Rural tourism: a risk factor for schistosomiasis transmission in Brazil.

    Science.gov (United States)

    Enk, Martin Johannes; Amaral, Graciela Larissa; Costa e Silva, Matheus Fernandes; Silveira-Lemos, Denise; Teixeira-Carvalho, Andréa; Martins-Filho, Olindo Assis; Correa-Oliveira, Rodrigo; Gazinnelli, Giovanni; Coelho, Paulo Marcos Zech; Massara, Cristiano Lara

    2010-07-01

    This paper reports an outbreak of acute schistosomiasis among 38 tourists who rented a country house in the district of Igarapé, the metropolitan region of Belo Horizonte, Brazil, during a holiday period in 2006. A total number of 32 individuals were positive for Schistosoma mansoni. Results of stool examinations revealed individual S. mansoni egg counts per gram of faeces (epg) ranging from 4-768 epg with a geometric mean egg count of 45. The most frequent clinical symptoms were abdominal pain (78.1%), headache (75%), fever (65.6%), dry cough (65.2%) and both diarrhoea and asthenia (59.4%). A malacological survey of the area, where 22 specimens of Biomphalaria glabrata were collected, revealed three (13.6%) specimens eliminating Schistosoma cercariae. This investigation re-confirms a recently described pattern of schistosomiasis infection, resulting in the acute form of the disease and connected to rural tourism, which contributes to the spread of the disease among the middle-class and into non-endemic areas. The lack of specific knowledge about acute schistosomiasis among health services causes an increased number of unnecessary diagnostic procedures and delays in accurate diagnosis and treatment, resulting in considerable discomfort for the patients. PMID:20721505

  18. Stability of Schistosoma mansoni progeny to antischistosomal drugs

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    Luiz Candido de Souza Dias

    1985-08-01

    Full Text Available The susceptibility of the MAP Brazilian strain (F1 to F5 progenies of S. mansoni to four antischistosomal drugs has been reported in a previous study. In the present investigation, progeny F14 of the same strain, was tested for stability to the same 4 drugs. A new medication, Oltipraz (35,972 RP, was added to the study. Five groups of 12 mice infected with cercariae by tail immersion were treated with hycanthone, oxamniquine, niridazole, praziquantel and Oltipraz. An untreated group was used as control. Schistosomal activity was assessed by the localization of worms in the portal vein system, by oogram changes, and percentage of parasite reduction. The stability of the susceptibility of progeny F14 did not change in relation to generations F1 to F5; the progeny was resistant to hycanthone and oxamniquine; but sensitive to niridazole, praziquantel and Oltipraz. We emphasize the importance of the phenomenon of resistance of the worm in view of the fact that oxamniquine has been widely used in Brazilian areas where mansonic schistosomiasis is endemic.

  19. Cloning of a cDNA encoding a surface antigen of Schistosoma mansoni schistosomula recognized by sera of vassinated mice

    Energy Technology Data Exchange (ETDEWEB)

    Dalton, J.P.; Tom, T.D.; Strand, M.

    1987-06-01

    Spleen cells of mice vaccinated with radiation-attenuated Schistosoma mansoni cercariae were used to produce monoclonal antibodies directed against newly transformed schistosomular surface antigens. One of these monoclonal antibodies recognized a polypeptide of 18 kDa. Binding was measured by radioimmunoassay. This glycoprotein was purified by monoclonal antibody immunoaffinity chromatography and a polyclonal antiserum was prepared against it. Immunofluorescence assays showed that the polyclonal antiserum bound to the surface of newly transformed schistosomula and lung-stage organisms but not to the surface of liver-stage and adult worms. Using this polyclonal antiserum we isolated recombinant clones from an adult worm cDNA expression library constructed in lambdagt11. Clone 654.2 contained an insert of 0.52 kilobase and hybridized to a 1.2-kilobase mRNA species from adult worms. Most importantly, clone 654.2 produced a fusion protein of 125 kDa that was reactive with sera of vaccinated mice that are capable of transferring resistance. This result encourages future vaccination trials with the fusion protein.

  20. Primeira ocorrência de Biomphalaria straminea no Sul Goiano, Brasil First occurrence of Biomphalaria straminea in the South Goiano, Brazil

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    Carlos Henrique Marchiori

    1999-12-01

    Full Text Available Relata-se a primeira ocorrência do Biomphalaria straminea no Sul do Estado de Goiás, em ambiente natural. Trinta exemplares de Biomphalaria straminea foram coletados em janeiro de 1998, em Cachoeira Dourada de Goiás. Verificou-se que a falta de saneamento e de educação sanitária da população e a presença do caramujo são condições fundamentais para o estabelecimento de um foco de transmissão.The objective of this note is to report the occurrence of the Biomphalaria straminea in the county of Cachoeira Dourada in the south of Goiás, and with that enhance the knowledge about its geographical distribution in the state. More than identify the species, the collection of thirty samples helped study and verify the presence of cercariae, especially because they were found in a setting which offers proper conditions to the development of a focal transmission site of schistosomiasis.

  1. UVB-induced immune suppression and infection with Schistosoma mansoni

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, F.P.; Lewis, F.A. [George Washington Univ., Washington, DC (United States). School of Medicine]|[Biomedical Research Inst., Rockville, MD (United States)

    1995-01-01

    Irradiation with ultraviolet B (UVB, 290-320 nm) causes a systematic immunosuppression of cell-mediated immunity. The question of whether UV immunosuppression modulates the course of infectious diseases is important because UVB levels in sunlight are sufficient to predict significant UV-induced immunosuppression at most latitudes. We have investigated the effect of immunosuppressive doses of UVB on the disease caused by the helminth parasite Schistosoma mansoni. C57BL/6 mice were irradiated once or three times weekly over 60-80 days with UV from a bank of FS40 sunlamps. Each UV treatment consisted of an immunosuppressive UV dose, as determined by suppression of contact hypersensitivity to trinitrochlorobenzene, corresponding to about 15-30 min of noonday tropical sunlight exposure under ideal clear sky conditions. Cumulative UV doses were between 80 and 170 kJ/m{sup 2}. Worm and egg burdens, liver granuloma diameters and liver fibrosis showed minimal changes (< 20%) compared with parameters in unirradiated animals. Ultraviolet irradiation (a total of 55 kJ/m{sup 2} administered in six treatments) did not impair the resistance to rechallenge conferred by vaccination with {sup 60}Co-irradiated cercariae. We have observed a dichotomy between UV immnosuppression and both disease and vaccination in this helminth infection, in contrast to the effects of UVB shown in other infectious diseases. (author).

  2. Rural tourism: a risk factor for schistosomiasis transmission in Brazil

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    Martin Johannes Enk

    2010-07-01

    Full Text Available This paper reports an outbreak of acute schistosomiasis among 38 tourists who rented a country house in the district of Igarapé, the metropolitan region of Belo Horizonte, Brazil, during a holiday period in 2006. A total number of 32 individuals were positive for Schistosoma mansoni. Results of stool examinations revealed individual S. mansoni egg counts per gram of faeces (epg ranging from 4-768 epg with a geometric mean egg count of 45. The most frequent clinical symptoms were abdominal pain (78.1%, headache (75%, fever (65.6%, dry cough (65.2% and both diarrhoea and asthenia (59.4%. A malacological survey of the area, where 22 specimens of Biomphalaria glabrata were collected, revealed three (13.6% specimens eliminating Schistosoma cercariae. This investigation re-confirms a recently described pattern of schistosomiasis infection, resulting in the acute form of the disease and connected to rural tourism, which contributes to the spread of the disease among the middle-class and into non-endemic areas. The lack of specific knowledge about acute schistosomiasis among health services causes an increased number of unnecessary diagnostic procedures and delays in accurate diagnosis and treatment, resulting in considerable discomfort for the patients.

  3. Schistosoma mansoni: respuesta celular hepática de ratones Balb/c infectados unisexualmente

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    Wolfan Araque

    2006-12-01

    Full Text Available The granulomatous response in animals infected with Schistosoma mansoni is attributed to the host reaction against the eggs, although the role of the adult worm is still controversial. The hepatic inflammatory response was studied in BALB/c mice unisexually (UNI infected with cercariae of S. mansoni by histopatology, immunofluorescence, immunohistochemistry and immunoelectronmicroscopy. The size of inflammatory infiltrate in liver of UNI infected mice, mean ± SD (33,9 ± 18, 86 µm2, the cells present included macrophages, lymphocytes, plasmocytes and few eosinophils. CD4+ and CD8+ cells in UNI infected mice were observed ( 2 to 4 cells/µm2 close to the worms and two patterns, either diffuse or in clusters in distant zones, in UNI and bisexual infections (BIS. The activated macrophages were observed close to worms and to schistosomal pigment. The results suggest that the adult worm is capable of inducing hepatic inflammatory response without granuloma formation, which elicit a significant in vivo macrophage and lymphocyte infiltrate, with probable implications in the pathogenesis of the murine schistosomiasis

  4. Schistosomiasis in Egypt: A never-ending story?

    Science.gov (United States)

    Othman, Ahmad A; Soliman, Rasha H

    2015-08-01

    Schistosomiasis has plagued the Egyptian population since the antiquity. The disease is still a public health problem in Egypt, despite the tendency of being overlooked. In the first part of this review, the past and current trends of schistosomiasis in Egypt are reviewed, including history, epidemiology, morbidity, therapy, and control of the disease. Most of these aspects are more or less relevant to other schistosome-endemic regions all over the world. As only one drug is currently available for individual treatment and preventive mass chemotherapy, the quest for complementary measures is urgently warranted. Indeed, one promising approach is the discovery of a vaccine. Herein, we point out the efforts of the Egyptian scientists to develop an efficacious and affordable vaccine against schistosomiasis - a step forward in the battle of elimination of Schistosoma infection. Based on the candidate vaccine antigens, four types of vaccine formulations are discussed: purified antigen vaccines, DNA constructs, attenuated cercariae, and excretory-secretory antigen vaccines. Finally, this review provides insights into this ancient seemingly long-lasting parasitic disease. PMID:25959770

  5. Local adaptation of the trematode Fasciola hepatica to the snail Galba truncatula

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    Dreyfuss G.

    2012-08-01

    Full Text Available Experimental infections of six riverbank populations of Galba truncatula with Fasciola hepatica were carried out to determine if the poor susceptibility of these populations to this digenean might be due to the scarcity or the absence of natural encounters between these snails and the parasite. The first three populations originated from banks frequented by cattle in the past (riverbank group whereas the three others were living on islet banks without any known contact with local ruminants (islet group. After their exposure, all snails were placed in their natural habitats from the end of October up to their collection at the beginning of April. Compared to the riverbank group, snails, which died without cercarial shedding clearly predominated in the islet group, while the other infected snails were few in number. Most of these last snails released their cercariae during a single shedding wave. In islet snails dissected after their death, the redial and cercarial burdens were significantly lower than those noted in riverbank G. truncatula. Snails living on these islet banks are thus able to sustain larval development of F. hepatica. The modifications noted in the characteristics of snail infection suggest the existence of an incomplete adaptation between these G. truncatula and the parasite, probably due to the absence of natural contact between host and parasite.

  6. Fasciola hepatica: comparative metacercarial productions in experimentally-infected Galba truncatula and Pseudosuccinea columella.

    Science.gov (United States)

    Vignoles, Philippe; Dreyfuss, Gilles; Rondelaud, Daniel

    2015-01-01

    As large numbers of metacercariae of Fasciola hepatica are necessary for research, experimental infections of Galba truncatula and Pseudosuccinea columella with this digenean were carried out to determine the better intermediate host for metacercarial production and, consequently, the most profitable snail for decreasing the cost price of these larvae. Pre-adult snails (4 mm in shell height) originating from two populations per lymnaeid species were individually exposed to two or five miracidia, raised at 23 °C and followed for cercarial shedding up to their death. Compared to values noted in G. truncatula, the survival of P. columella on day 30 post-exposure was significantly greater, while the prevalence of F. hepatica infection was significantly lower. In the four P. columella groups, metacercarial production was significantly greater than that noted in the four groups of G. truncatula (347-453 per cercariae-shedding snail versus 163-275, respectively). Apart from one population of G. truncatula, the use of five miracidia per snail at exposure significantly increased the prevalence of F. hepatica in P. columella and the other population of G. truncatula, whereas it did not have any clear effect on the mean number of metacercariae. The use of P. columella for experimental infections with F. hepatica resulted in significantly higher metacercarial production than that noted with G. truncatula, in spite of a lower prevalence for the former lymnaeid. This finding allows for a significant decrease in the cost price of these larvae for commercial production.

  7. Fasciola hepatica: comparative metacercarial productions in experimentally-infected Galba truncatula and Pseudosuccinea columella

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    Vignoles Philippe

    2015-01-01

    Full Text Available As large numbers of metacercariae of Fasciola hepatica are necessary for research, experimental infections of Galba truncatula and Pseudosuccinea columella with this digenean were carried out to determine the better intermediate host for metacercarial production and, consequently, the most profitable snail for decreasing the cost price of these larvae. Pre-adult snails (4 mm in shell height originating from two populations per lymnaeid species were individually exposed to two or five miracidia, raised at 23 °C and followed for cercarial shedding up to their death. Compared to values noted in G. truncatula, the survival of P. columella on day 30 post-exposure was significantly greater, while the prevalence of F. hepatica infection was significantly lower. In the four P. columella groups, metacercarial production was significantly greater than that noted in the four groups of G. truncatula (347–453 per cercariae-shedding snail versus 163–275, respectively. Apart from one population of G. truncatula, the use of five miracidia per snail at exposure significantly increased the prevalence of F. hepatica in P. columella and the other population of G. truncatula, whereas it did not have any clear effect on the mean number of metacercariae. The use of P. columella for experimental infections with F. hepatica resulted in significantly higher metacercarial production than that noted with G. truncatula, in spite of a lower prevalence for the former lymnaeid. This finding allows for a significant decrease in the cost price of these larvae for commercial production.

  8. The Effect of an Eextremely Low Frequency Magnetic Field on Larvae Production in the Parasite-Host System: Fasciola hepatica-Galba truncatula: a Preliminary Study.

    Science.gov (United States)

    Kołodziejczyk, Lidia; Podraza, Wojciech; Gonet, Bolesław; Dzika, Ewa; Kosik-Bogacka, Danuta I

    2016-01-01

    The aim of this study was to determine the effect of an extremely low-frequency magnetic field (ELFMF) on the production of liver fluke larvae in a parasite-host system: Fasciola hepatica--Galba truncatula. Both F. hepatica eggs and F. hepatica-infected snails were exposed to an ELFMF (50 Hz, 2.0 mT) for 14 days and 36 days, respectively. F. hepatica-infected snails were divided into 4 groups, 10 specimens each. The snails of groups I and II were infected with F. hepatica larvae--miracidia obtained from control cultures, while the snails of groups III and IV were infected with miracidia reared from eggs that had been incubated in an ELFMF. After infection, the snails of groups II and IV were placed in an ELFMF, while those of groups I (control) and III were housed outside the ELFMF. At 36 days post-infection (dpi) there were no statistically significant differences between the number of F. hepatica larvae--cercariae and metacercariae, obtained from G. truncatula snails in the control group (group I) and the snail groups exposed to ELFMF (groups II, III and IV). However, a statistically significant difference between the average number of F. hepatica larvae in snail groups III and IV may indicate that the duration of exposure to ELFMF, i.e. embryogenesis period vs. the entire larval development, played a role in the production of F. hepatica larvae, and resulted in a reduction of their number.

  9. COMMUNITY CO-DESIGNED SCHISTOSOMIASIS CONTROL INTERVENTIONS FOR SCHOOL-AGED CHILDREN IN ZANZIBAR.

    Science.gov (United States)

    Person, B; Knopp, S; Ali, S M; A'kadir, F M; Khamis, A N; Ali, J N; Lymo, J H; Mohammed, K A; Rollinson, D

    2016-09-01

    Top-down biomedical interventions to control schistosomiasis in sub-Saharan Africa have had limited success, primarily because they fail to engage with the social, political, economic and ecological contexts in which they are delivered. Despite the call to foster community engagement and to adapt interventions to local circumstances, programmes have rarely embraced such an approach. This article outlines a community co-designed process, based upon Human-Centered Design, to demonstrate how this approach works in practice. It is based on initial work undertaken by social science researchers, public health practitioners and community members from the Zanzibar Islands, Tanzania, between November 2011 and December 2013. During the process, 32 community members participated in a qualitative and quantitative data-driven workshop where they interpreted data on local infections from S. haematobium and co-designed interventions with the assistance of a facilitator trained in the social sciences. These interventions included the implementation of novel school-based education and training, the identification of relevant safe play activities and events at local schools, the installation of community-designed urinals for boys and girls and the installation of community-designed laundry-washing platforms to reduce exposure to cercariae-contaminated fresh water. It is suggested that the a community co-designed process, drawing from Human-Centered Design principles and techniques, enables the development of more sustainable and effective interventions for the control of schistosomiasis. PMID:27428066

  10. Schistosome-Derived Molecules as Modulating Actors of the Immune System and Promising Candidates to Treat Autoimmune and Inflammatory Diseases.

    Science.gov (United States)

    Janssen, Luis; Silva Santos, Gisele Lorranna; Muller, Herick Sampaio; Vieira, Anderson Rodrigues Araújo; de Campos, Tatiana Amabile; de Paulo Martins, Vicente

    2016-01-01

    It is long known that some parasite infections are able to modulate specific pathways of host's metabolism and immune responses. This modulation is not only important in order to understand the host-pathogen interactions and to develop treatments against the parasites themselves but also important in the development of treatments against autoimmune and inflammatory diseases. Throughout the life cycle of schistosomes the mammalian hosts are exposed to several biomolecules that are excreted/secreted from the parasite infective stage, named cercariae, from their tegument, present in adult and larval stages, and finally from their eggs. These molecules can induce the activation and modulation of innate and adaptive responses as well as enabling the evasion of the parasite from host defense mechanisms. Immunomodulatory effects of helminth infections and egg molecules are clear, as well as their ability to downregulate proinflammatory cytokines, upregulate anti-inflammatory cytokines, and drive a Th2 type of immune response. We believe that schistosomes can be used as a model to understand the potential applications of helminths and helminth-derived molecules against autoimmune and inflammatory diseases. PMID:27635405

  11. Identification and characterization of surface antigens in parasites, using radiolabelling techniques

    International Nuclear Information System (INIS)

    Surface proteins of Schistosoma sp and Leishmania sp were studied using 125-Iodine as tracer. The surface proteins were labelled by the Lactoperoxidase method and the proteins then separated using SDS PAG electrophoresis and autoradiography. The possible immunogens were then separated using immunoprecipitation and Fluorescent Antibody techniques using sera from patients or from artificially immunized rabbits. Four common antigens were identified from the surfaces of male and female adult worms, cercariae and schistosomulae of S.mansoni. These antigens, which had molecular weights of 150,000, 78,000, 45,000, and 22,000 were also isolated from the surfaces of S.haematobium adults. The surface antigens on promastigotes of a Kenyan strain of Leishmania donovani were separated into three protein antigens with molecular weights of 66,000, 59,000 and 43,000 respectively. The 59,000 molecular weight antigen was a glycoprotein and was common to promastigotes of an American and Indian strain of L.donovani and to L.braziliensis mexicana. None of the isolated antigens have been shown to have a protective effect when vaccinated into mice, but the study illustrates the value of radionuclide tracers in the unravelling of the mosaic of antigens which parasites possess

  12. The prolonged use of niclosamide as a molluscicide for the control of Schistosoma mansoni Uso prolongado da niclosamida como moluscicida para o controle do Schistosoma mansoni

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    Pedro Coura-Filho

    1992-10-01

    Full Text Available Applications of niclosamide at three-monthly intervals were undertaken for 14 years in foci of Biomphalaria glabrata in the water sources of Peri-Peri (Capim Branco, MG. All the residents of the area were submitted to an annual fecal examination (Kato/Katz and those individuals eliminating Schistosoma mansoni eggs were treated with oxamniquine. A malacological survey was undertaken at three-monthly intervals by means of ten scoops with a perforated ladle each ten metres along the two banks of the ditches and streams of the region. Where snails were found, molluscicide was applied by means of dripping or aspersion using a 3 ppm aqueous suspension of niclosamide. Initially, a mean of 14.3% of snails in the region were found to be eliminating cercariae. Following the first four applications of molluscicide, this was reduced to 0.0% and maintained at about 1.5% throughout the program. Thus, there was a continued possibility of schistosomiasis transmission in the area and it was observed that the population of snails reestablished itself within three months of molluscicide application. The results obtained in this study do not encourage the continual use of niclosamide as the only method of control of schistosomiasis.Aplicações trimestrais de niclosamida foram realizadas catorze anos em focos de Biomphalaria glabrata nas coleções hídricas de Peri-Peri, (Capim Branco, MG. Anualmente, os residentes da área eram submetidos a um exame coproscópio (Kato-Katz e os que eliminavam ovos de Schistosoma mansoni nas fezes eram tratados com oxarnniquine. O levantamento malacológico trimestral foi realizado através de dez conchadas a cada dez metros nas duas margens das valas e córregos da região. Onde eram encontrados caramujos aplicava-se o moluscicida pela técnica de gotejamento ou aspersão de suspensão aquosa da niclosamida a 3 ppm. O índice médio de caramujos eliminando cercarias na região era de 14,3%. Após as quatro primeiras aplica

  13. Epidemiological studies of amphistome infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

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    D.M. Pfukenyi

    2005-09-01

    intermediate host for amphistomes was B. tropicus with a prevalence of infection of 8.5 %. However, amphistome cercariae were also recorded in Biom. Pfeifferi and B. forskalii. Amphistome cercariae were recorded from both the highveld and lowveld areas with peak prevalence during the post-rainy season (March to May. Metacercariae were found on herbage from the fringes of the snail habitats between February and August, with most of the metacercariae concentrated on herbage 0-1 m from the edges of the habitats. Based on the epidemiological findings a control programme was devised. From this study, large burdens of immature flukes could be expected in cattle during the dry months. Since adult cattle would be resistant to the pathogenic effects of the migrating immature amphistomes the target for control would be young animals being exposed to the infection for the first time. Therefore, the first anthelmintic treatment can be administered in calves in mid June when maximum migration of immature amphistomes starting 3-4 weeks after infection in the early dry season would be expected. A second treatment could be given in late July or early August to remove potentially dangerous burdens of immature flukes acquired later in the dry season. Where resources permit, another strategy would be to treat against the mature flukes in March or April in order to reduce the number of eggs deposited on pastures and the opportunity for infection of the intermediate host snails. To reduce cercarial shedding by the intermediate host snails molluscicides can also be applied during the peak transmission periods (April/May and August/September.

  14. 福建省政和县东部并殖吸虫病疫源地调查%Investigation on epidemic foci of paragonimiasis in eastern part of Zhenghe County,Fujian Province

    Institute of Scientific and Technical Information of China (English)

    林本翔; 魏焕旺; 李友松; 吴世清; 孔凡真; 范治金; 汤保贵; 陈财

    2016-01-01

    Objective To investigate the species and hosts of Paragonimus and its infection rate in eastern part of Zhenghe County,Fujian Province,so as to determine the local foci of Paragonimus. Methods The snails,crabs and stools of wild cats were collected for the examinations of cercariae,metacercariae and eggs of Paragonimus. The geographical and environmental conditions of the areas were also investigated. Results A total of 4 890 Pseudobythinella jianouensis snails and 1 035 Semisul⁃cospira liberlina snails were examined,and the cercariae of Paragonimus were only found in P. jianouensis,with an infection rate of 0.10%(5/4 890). Bottapotamon zhengheensis sp. nov. as the second intermediate host of P. skrjabini,were examined, and the infection rate was 85.29%(29/34)and the average numbers of metacercariae per crab and per gram of crab tissues were 3.85 and 0.62,respectively. Thirty⁃six Sinopotamun fujianensis crabs,as the second intermediate host of P. westermani,were examined,and the infection rate was 38.89%(14/36)and the average numbers of metacercariae per crab and per gram of crab tissues were 6.43 and 0.03,respectively. The eggs of Paragonimus were detected in 1 of 2 muck specimens of wild cats. Conclu⁃sion The data suggest that there is a focus of middle⁃to⁃high level of infection caused by P. westermani and P. skrjabini in the eastern part of Zhenghe County.%目的:对福建省政和县东部并殖吸虫虫种、宿主种类及其感染率进行调查,以确定当地并殖吸虫病疫源地。方法采集政和县当地淡水螺、蟹及野猫粪便,检查螺体内并殖吸虫尾蚴、蟹体内囊蚴和野猫粪便中的虫卵。结果共检查1035只放逸短沟蜷和4890只建瓯拟小豆螺;仅在建瓯拟小豆螺体内发现并殖吸虫尾蚴,其感染率为0.10%(5/4890)。检查政和博特溪蟹34只,其中29只感染斯氏并殖吸虫囊蚴,感染率为85.29%,每只蟹及每克蟹组织平均囊蚴数分别为3.85个和0.62

  15. HOSPES PERANTARA DAN HOSPES RESERVOIR FASCIOLOPSIS BUSKI DI INDONESIA Studi Epidemiologi F. buski di Kabupaten Hulu Sungai Utara, Kalimantan Selatan Tahun 2002 dan 2010

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    Anorital -

    2013-12-01

    Full Text Available ABSTRACT Buski intestinal worm disease (fasciolopsiosis is an endemic disease in some villages in the Hulu Sungai Utara district. Since the discovery of the case in 1982 until recently, the fasciolopsiosis prevalence has not showed a declining trend. Even in some periods it seems to rise, despite mitigation efforts continue to be implemented through various surveys, which ended with the drugs administration.Unidentified intermediate hosts and reservoir hosts is one constraint in the disease control.To determine the epidemiological cycle of F. buski, two studies were conducted by two research institutions under the Research and Development Agency in 2002 by Anorital, etal. and 2010 by Annida.Results from both studies showed that there were 3 kinds of water plants (second intermediate host consumed by communities; the lily (Nymphea alba, bird lotus(Nymphea lotus and water spinach (Ipomea aquatica which was positive of Metasercariae and Cercariae. Two of four types of freshwater snails (the first intermediate host specimens examined were positive of redia and cercariae; kalambuai snail (Lymnea sp. and flat snails (Indoplanorbis sp.. One of four animal manure specimens examined was positive of F. buski egg (found in buffalo dung. It was also found two egg specimens from chicken and alabio duck manure whichis resembled to F. buski. But in terms ofsize, it was much smaller than the egg of F. buski. Despite these positive findings, the confirmation from experienced research institutions is needed. It is expected that the Buski intestinal worm disease (fasciolopsiosis control can be conducted effectively. An in-depth study is also needed. Key words: Fasciolopsis buski, fasciolopsiosis. ABSTRAK Penyakit kecacingan buski (fasciolopsiosis merupakan penyakit yang endemis di beberapa desa di kabupaten Hulu Sungai Utara. Sejak ditemukan kasus penyakit ini pada tahun 1982 dan sampai saat ini, prevalensi fasciolopsiosis tidak menunjukkan kecenderungan menurun

  16. Esquistossomose mansoni em duas mesorregiões do Estado de Alagoas Schistosomiasis mansoni in two mesoregions of the State of Alagoas

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    Janira Lúcia Assumpção Couto

    2005-08-01

    mesoregion of the Agreste Alagoano. The snails collected for analysis came from different types of habitats, namely streams, springs, ditches, dams, swamps, wells and ponds. The snails were collected from February 1996 through December 1998. The identification of Biomphalaria glabrata was made through anatomical analysis of the soft inner parts of the snails after having been removed their shells. As for the detection of cercariae of Schistosoma mansoni, the crush technique was applied in order to calculate the percentage of infection rates. Among the areas surveyed, 32 municipalities (80% of the total, presented the species Biomphalaria glabrata, six of which containing snails infected with cercariae of the parasite. Penedo presented the highest infection rate (6.6%, followed by Ibateguara (5.6%. Lower rates were noticed in Chã Preta (2.7%, in Murici (2.5%, Porto Real do Colégio (0.1% and Igreja Nova (0.1%.The coproparasitologic analyses conducted at the Fundação Nacional de Saúde in 1997, 1998/1999 and 2000, confirmed the importance of schistosomiasis mansoni in the areas surveyed in this work.

  17. A contribution to the study of acute schistosomiasis (an experimental trial Contribuição ao estudo da esquistossomose aguda (uma tentativa experimental

    Directory of Open Access Journals (Sweden)

    Zilton A. Andrade

    1987-09-01

    Full Text Available In an attempt to establish an experimental model of acute schistosomiasis, sequential histological changes were investigated in the skin, lung, liver and spleen of mice infected with 30 or 100 cercariae of Schistosoma mansoni according to four sets of experiments: single infection, repeated infections, unisexual infection and infection in mice born from infected mothers. Animals were killed every other day from exposure up to 50 days after infection. Only mild, isolated, focal inflammatory changes were found before the appearance of mature eggs in the liver, even when repeated infections were made. Severe changes of reactive hepatitis and splenitis appeared suddenly when the first mature eggs were deposited, around the 37th to 42nd day after infection. The mature eggs induced lytic and coagulative necrosis of hepatocytes around them which was soon followed by dense infiltration of eosinophils. So, mature egg-induced lesions appeared as the major factors in the pathogenesis of acute schistosomiasis in mice. Mice born from infected mothers were apparently able to rapidly modulate the egg-lesions, forming early fibrotic granulomas. The murine model of acute schistosomiasis appeared adequate for the study of pathology and pathogenesis of acute schistosomiasis.Numa tentativa para se estabelecer um modelo experimental para o estudo da esquistossomose aguda foram estudadas as alterações presentes na pele, pulmões, fígado e baço de comundongos submetidos a infecção com 30 ou 100 cercarias do Schistosoma mansoni e divididos em quatro tipos de experimentos: infecção simples, infecções repetidas, infecção unissexuada e infecção em animais provenientes de mães infectadas. Os animais foram sacrificados em dias alternados a partir do momento da infecção até 50 dias depois. As lesões encontadas na fase pré-postural foram discretas e poucas, mesmo quando os animais foram submetidos a infecções repetidas. As alterações mais súbitas e

  18. Urinary Schistosomiasis in Urban and Semi-Urban Communities in South-Eastern Nigeria

    Directory of Open Access Journals (Sweden)

    Ogochukwu Caroline Okeke

    2013-09-01

    Full Text Available Background: In view of the massive rural-to-urban migration in Nigeria, investiga­tions on transmission of urinary schistosomiasis were carried out in ur­ban and semi-urban communities in Nike Lake area of Enugu State, Nigeria.Methods: Urine samples of school children were tested for micro-haematuria using reagent strips followed by microscopic examination for Schistosoma haemato­bium eggs. Water contact sites were also identified and sampled for snails.Results: The overall prevalence of S. haematobium eggs in school children was 4.64%. The mean intensity of infection was 1.14 + 0.41 eggs/10ml urine. Males had insignificantly higher prevalence and intensity of S. haematobium infec­tion than females. The youngest age group (4-7 years had no infection. The preva­lence of micro-haematuria (6.2% was higher than that of microscopy, and this correlated positively with prevalence (r=0.65, P < 0.01 and intensity (r=0.50, P < 0.01 of the infection. Potential intermediate host of human shistosome collected were: Bulinus globosus, B. senegalensis and Biomphalaria pfeifferi. How­ever, only B. globosus shed cercariae of S. haematobium, with a snail infection rate of 0.73%. Transmission was in the dry season coinciding with the drying of wells.Conclusion: The results revealed that urinary schistosomiasis is prevalent, and that B. globosus and not B. truncatus as previously reported is the main interme­diate host of urinary schistosomiasis in this part of Enugu State

  19. Melatonin and schistosomal antigens ameliorate the anti-oxidative and biochemical response to Schistosoma mansoni infection in hamster

    Institute of Scientific and Technical Information of China (English)

    Nahla S.El-SHENAWY; Maha F.M.SOLIMAN; Shimaa E.Abel-RAHMAN

    2009-01-01

    The present study was designed to investigate the potential protective effect of melatonin as an antioxidant separately or in combination with antigens (cercarial; CAP or soluble worm; SWAP) against Schistosoma mansoni infection in hamsters. Each hamster was sensitized with an initial immunization of 0.6 ml of the extracted antigen (30 μg protein/mL). After four days, a second injection of 0.4 mL was given (20 μg protein/mL). Then, each hamster was exposed to 260±20 S.mansoni cercariae followed with melatonin treatment (3.5 mg/kg) for thirty days from the 1st day of post infection. Levels of lipid peroxidation (LPO) products, catalase (CAT) activity, hepatic glutathione (GSH) and biochemical changes in the liver and kidneys functions were investigated. The results revealed a high significant increasing of LPO and decreasing of CAT and GSH in liver of infected hamsters. Biochemical observations showed severe damage in the liver enzyme activities and increasing cholesterol level in infected animals. Melatonin co-treatment with antigen to the infected-hamster attenuated the increase of LPO and restored the activity of CAT and levels of hepatic GSH. Also, the biochemical damages in the liver and kidneys functions were reduced. The present study suggests that melatonin may be useful in combating free radical-induced damage due to infection toxicity. The immunization with previous antigens resulted in a remarkable improvement on the liver enzyme activities, which were increased after infection. Thus, vaccination of hamsters with antigens (both CAP and SWAP) and melatonin treatment has more potent effect on the enhancement of antioxidant and biochemical of S.mansoni infected-hamster than each treatment separately. Immunization of the hamster with SWAP followed by melatonin was the best way among the other regime treatments to improve the biochemical and antioxidant parameters of the infected-hamsters[Current Zoology 55(2):165-172,2009].

  20. Dynamic Observation of Liver Fibrosis in Mice Infected with Schistosoma japonica

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The expression of TNF-α in the liver at different periods post Schistosoma japonica infection and the effect on liver fibrosis after supplementary injection of these eytokines were investigated. The mice infected with schistosome cercariae were divided into 3 groups: normal control group, TNF-α-untreated infection group and TNF-α-treated infection group. ABC immunohistochemistry and pathologic image multimedia quantification system were applied to dynamically detect the activity of TNF-α. The results showed that the levels of TNF-α in the liver in TNF-α-untreated infection group were slowly decreased with prolongation of infection time (from 8th, 11th, 14th to 18th week), while in the TNF-α-treated infection group, those were increased significantly after intraperitoneal injection of TNF-α at 6th week after infection. At first to 8th week after the final injection of TNF-α, the intrahepatic TNF-α levels in the TNF-α-treated infection group were significantly higher than in the other two groups (P<0.01), and the granulomatous inflammation and fibrosis in the liver were also milder in the normal control group. It was concluded that at the early stage of Schistosoma japonica infection mouse liver mainly released Th1 cytokine and TNF-α from Th1 activated macrophages. Six weeks after infection (post egg deposition), exogenous supplement with intraperitoneal injection of TNF-α could induce the enhanced expression of Th1 cytokines and alleviate the liver granulomatous inflammation and fibrosis.

  1. Discovery of Antischistosomal Drug Leads Based on Tetraazamacrocyclic Derivatives and Their Metal Complexes.

    Science.gov (United States)

    Khan, M O Faruk; Keiser, Jennifer; Amoyaw, P N A; Hossain, Mohammad F; Vargas, Mireille; Le, Justin G; Simpson, Natalie C; Roewe, Kimberly D; Freeman, TaRynn N Carder; Hasley, Travis R; Maples, Randall D; Archibald, Stephen J; Hubin, Timothy J

    2016-09-01

    Praziquantel (PZQ) is the only drug available for the treatment of schistosomiasis, and since its large-scale use might be associated with the onset of resistance, new antischistosomal drugs should be developed. A series of 26 synthetic tetraazamacrocyclic derivatives and their metal complexes were synthesized, characterized, and screened for antischistosomal activity by application of a phased screening program. The compounds were first screened against newly transformed schistosomula (NTS) of harvested Schistosoma mansoni cercariae, then against adult worms, and finally, in vivo using the mouse model of S. mansoni infection. At a concentration of 33 μM, incubation with a total of 12 compounds resulted in the mortality of NTS at the 62% to 100% level. Five of these showing 100% inhibition of viability of NTS at 10 μM were selected for further screening for determination of the 50 inhibitory concentrations (IC50s) against both NTS and adult worms. Against NTS, all 5 compounds showed IC50s comparable to the IC50 of the standard drug, PZQ (0.87 to 9.65 μM for the 5 compounds versus 2.20 μM for PZQ). Three of these, which are the bisquinoline derivative of cyclen and its Fe(2+) and Mn(2+) complexes, showed micromolar IC50s (1.62 μM, 1.34 μM, and 4.12 μM, respectively, versus 0.10 μM for PZQ) against adult worms. In vivo, the worm burden reductions were 12.3%, 88.4%, and 74.5%, respectively, at a single oral dose of 400 mg/kg of body weight. The Fe(2+) complex exhibited activity in vivo comparable to that of PZQ, pointing to the discovery of a novel drug lead for schistosomiasis. PMID:27324765

  2. Bioquímica da esquistossomose mansônica: envolvimento dos siderossomos nos processos inflamatórios hepáticos

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    Luiz Erlon Araújo Rodrigues

    1990-06-01

    Full Text Available Os processos inflamatórios que se desenvolvem durante as etapas avançadas da esquistossomose mansônica hepática foram relacionados, com o acúmulo de siderossomos, a capacidade dos íons ferrosos/férricos de desencadearem a formação de radicais livres e aperoxidação de lipídios membranáceos, assim como à diminuição da estabilidade das membranas dos diversos componentes do compartimento lisossômico hepático. Os lisossomos isolados de figados de camundongos infectados por 100 cercárias, com 80 e 100 dias de infecção, foram respectivamente, 2,5 e quase 4 vezes mais frágeis que os controles, isolados de figados de camundongos não infectados. A presença de siderossomos em grande quantidade foi demonstrada por espectrometria aos raios-X.The inflammatory processes that develop during the advanced stages of hepatic Schistosomiasis mansoni have been related in this study to: (a accumulation of siderosomes; (b capacity of the ferrous/ferric ions to unleash the formation of free radicals; (c peroxidation of membranaceous lipids and; (d reduction of stability of the membranes of several components of the hepatic lysosomal compartment. The lysosomes isolated from the livers of infected mice by 100 cercariae, with 80 and 100 days of infection, were respectively 2.5 and almost 4 times weaker than the control ones isolated from livers of non-infected mice. The presence of a great quantity of siderosomes has been demonstrated by transmission electronic microscopy and X-ray spectrometry microanalysis.

  3. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni.

    Science.gov (United States)

    Arican-Goktas, Halime D; Ittiprasert, Wannaporn; Bridger, Joanna M; Knight, Matty

    2014-09-01

    Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro that Biomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their nuclear location and becoming up-regulated. This also happens in vivo in live intact snails, where early exposure to miracidia also elicits non-random repositioning of genes. We reveal differences in the nuclear repositioning between the response of parasite susceptible snails as compared to resistant snails and with normal or live, attenuated parasites. Interestingly, the stress response gene heat shock protein (Hsp) 70 is only repositioned and then up-regulated in susceptible snails with the normal parasite. This movement and change in gene expression seems to be controlled by the parasite. Other differences in the behaviour of genes support the view that some genes are responding to tissue damage, for example the ferritin genes move and are up-regulated whether the snails are either susceptible or resistant and upon exposure to either normal or attenuated parasite. This is the first time host genome reorganisation has been seen in a parasitic host and only the second time for any pathogen. We believe that the parasite elicits a spatio-epigenetic reorganisation of the host genome to induce favourable gene expression for itself and this might represent a fundamental mechanism present in the human host infected with schistosome cercariae as well as in

  4. Influence of Trichobilharzia regenti (Digenea: Schistosomatidae on the defence activity of Radix lagotis (Lymnaeidae Haemocytes.

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    Vladimír Skála

    Full Text Available Radix lagotis is an intermediate snail host of the nasal bird schistosome Trichobilharzia regenti. Changes in defence responses in infected snails that might be related to host-parasite compatibility are not known. This study therefore aimed to characterize R. lagotis haemocyte defence mechanisms and determine the extent to which they are modulated by T. regenti. Histological observations of R. lagotis infected with T. regenti revealed that early phases of infection were accompanied by haemocyte accumulation around the developing larvae 2-36 h post exposure (p.e. to the parasite. At later time points, 44-92 h p.e., no haemocytes were observed around T. regenti. Additionally, microtubular aggregates likely corresponding to phagocytosed ciliary plates of T. regenti miracidia were observed within haemocytes by use of transmission electron microscopy. When the infection was in the patent phase, haemocyte phagocytic activity and hydrogen peroxide production were significantly reduced in infected R. lagotis when compared to uninfected counterparts, whereas haemocyte abundance increased in infected snails. At a molecular level, protein kinase C (PKC and extracellular-signal regulated kinase (ERK were found to play an important role in regulating these defence reactions in R. lagotis. Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells. These data provide the first integrated insight into the immunobiology of R. lagotis and demonstrate modulation of haemocyte-mediated responses in patent T. regenti infected snails. Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.

  5. Occurrence of a Snail Borne Disease, Cercarial Dermatitis (Swimmer Itch in Doon Valley (Uttarakhand, India.

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    Rakesh Kumar Jauhari

    2014-02-01

    Full Text Available 'Cercarial dermatitis' also known as swimmers itch (Skin allergies is caused by a trematode parasite, Schistosoma which has two hosts - an invertebrate (snail and a vertebrate (livestock, human being. Although the availability of both vector snails and pathogens at the selected site the Doon Valley in northern India has already been confirmed but there was a hazy picture of the disease, whether it is due to entrance of cercariae or due to wild variety of grass (Parthenium hysterophorus. The present study is an attempt to provide a way forward towards the vector snails and snail borne diseases in the study area.Snail sampling and identification was done by applying standard methods / using Keys & Catalogues. Associated parasites and cercariometry in snails has been worked out by cercarial shedding. Human involvement at zo-onotic level has been performed in collaboration with Health centers and socio- economic aspect of inhabitants of study area.The snail diversity encountered 19 species including the vector species such as Indoplanorbis exustus, Gyraulus convexiusculus, Melanoides tuberculata and Lymnaea acuminata. The cercarial diversity comprised Furcocercous, Monostome, Amphistome and liver fluke / Xiphidiocercaria. During the study (2009-2010, 0.173% was found with cercarial dermatitis among human population in the selected area. The symptoms of disease recorded were red spots and swellings on effected parts of skin. Frequent visits of livestock to the water body and presence of vector snails provides a clue in completing the life cycle of the parasite of the family Schistosomatidae.Cercarial dermatitis has been considered a potential risk at those places where warm blooded and snail's hosts share a link with aquatic bodies with particular emphasis to temperature and time of year.

  6. Two New Species of Homalometron (Digenea: Apocreadiidae) from Nearctic Freshwater Fundulids, Elucidation of the Life Cycle of H. cupuloris, and Molecular Phylogenetic Analysis of Some Congeners.

    Science.gov (United States)

    Fayton, Thomas J; Curran, Stephen S; Andres, Michael J; Overstreet, Robin M; McAllister, Chris T

    2016-02-01

    Two species of digeneans belonging in Homalometron are described from Nearctic freshwater fundulid fishes: Homalometron robisoni n. sp. is described from the Blackstripe Topminnow, Fundulus notatus, from Oklahoma and Homalometron frocioneae n. sp. is described from the Banded Killifish, Fundulus diaphanus, from New York. Homalometron robisoni n. sp. differs from all congeners by having vitelline follicles that extend into the forebody, a feature that necessitates altering the generic diagnosis for the genus. Homalometron frocioneae n. sp. may be distinguished from North and Middle American congeners by the position of the intestinal bifurcation (relatively more posterior in the forebody than in other species) and tegumental spine coverage on the body (spines are absent from the posterior body extremity and on most of the dorsal surface). Comparison of ribosomal DNA (ITS 1 and 2 regions, 5.8S gene, and partial fragment of 28S gene) from the 2 new species and some congeners from the Western Hemisphere provided evidence for the validity of the 2 new species and affirmed a close relationship between H. robisoni n. sp. and Homalometron pallidum. Comparison of ribosomal DNA from newly collected Homalometron spp. and larval stages of an apocreadiid from brackish water hydrobiid snails (cercariae in rediae in Littoridinops palustris and metacercariae in L. palustris and Amnicola limosa ) from a tidal river in Mississippi revealed that larval stages represented Homalometron cupuloris. A phylogeny based on Bayesian inference analysis using partial 28S rDNA gene fragments from 14 species of Homalometron (all from the Western Hemisphere) and 1 megaperine and rooted by a second megaperine was conducted and produced a strongly supported phylogram that estimates the interrelationships among species. The estimated phylogeny suggests that ecological factors such as salinity and food web interactions between species of Homalometron, intermediate hosts, and fishes drive

  7. Effect of praziquantel administration on hepatic stereology of mice infected with Schistosoma mansoni and fed a low-protein diet

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    L.A. Barros

    2009-09-01

    Full Text Available A study was undertaken to investigate the effect of administering praziquantel (PZQ, focusing on the liver stereological findings of malnourished mice infected with Schistosoma mansoni. Thirty female Swiss Webster mice (age: 21 days; weight: 8-14 g were fed either a low-protein diet (8% or standard chow (22% protein for 15 days. Five mice in each group were infected with 50 cercariae each of the BH strain (Brazil. PZQ therapy (80 mg/kg body weight, per day was started on the 50th day of infection and consisted of daily administration for 5 days. Volume density (hepatocytes, sinusoids and hepatic fibrosis was determined by stereology using a light microscope. Body weight gain and total serum albumin levels were always lower in undernourished mice. Our stereological study demonstrated that treatment increased both volume density of hepatocytes in mice fed standard chow (47.56%, treated group and 12.06%, control and low-protein chow (30.98%, treated group and 21.44%, control, and hepatic sinusoids [standard chow (12.52%, treated group and 9.06%, control, low-protein chow (14.42%, treated group and 8.46%, control], while hepatic fibrosis was reduced [standard chow (39.92%, treated group and 78.88%, control and low-protein chow (54.60%, treated group and 70.10%, control]. On the other hand, mice fed low-protein chow decreased density volume of hepatocytes and hepatic fibrosis. In conclusion, our findings indicate that treatment with PZQ ameliorates hepatic schistosomiasis pathology even in mice fed a low-protein diet.

  8. Diagnostic and prognostic value of cell free circulating Schistosoma mansoni DNA: an experimental study.

    Science.gov (United States)

    Eraky, Maysa Ahmad; Aly, Nagwa Shaban Mohamed

    2016-09-01

    Searching for a more sensitive and accurate marker for schistosomiasis diagnosis and treatment follow up is a potential necessity. Hereby, we evaluated usefulness of circulating free DNA as a marker for schistosomiasis diagnosis, assessing drug efficacy and monitoring the control interventions impact using SYBR green real-time PCR. A batch of mice were infected by 90 ± 10 Schistosoma mansoni cercariae. Starting from the 2nd day post infection (p.i.), groups of 2 or 3 mice were sacrificed every 3 days until 30 days p.i. The remaining animals were treated by a single dose of 400 mg/kg mefloquine and sacrificed in group at 5, 10, 21 days post treatment (35, 40, 51 days p.i.). Using SYBR green real time qPCR, pooled sera DNA were extracted and amplified. The results showed that, circulating free S. mansoni DNA was detected from the 2nd day post infection (p.i.) onwards with gradual decrease in the cycle threshold value Ct which indicates the gradual elevation of the DNA level (Log quantity was 2.6-3.1 IU/ml), As the infection progressed, DNA quantity was increased(Log quantity was 6.29 IU/ml). Initial increase of circulating free DNA was observed 10 days post treatment (40 days p.i.) (Log quantity was 7.38 IU/ml). That was followed by a progressive decrease in DNA level by the end of 21st day, post treatment (51 p.i.) (Log quantity 4.35 IU/ml). In conclusion, circulating free S. mansoni DNA is a reliable marker in the diagnosis of schistosomiasis and for assessing drug efficacy and monitoring the impact of control interventions. PMID:27605830

  9. Composição e sazonalidade dos moluscos do alto rio Paraná, Brasil, e sua potencialidade como hospedeiros intermediários de digenéticos - DOI: 10.4025/actascibiolsci.v30i3.5018 Composition and seasonality of mollusks from the upper Paraná river, Brazil, and their potentiality as intermediate hosts for digeneans - DOI: 10.4025/actascibiolsci.v30i3.5018

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    Gilberto Cezar Pavanelli

    2008-10-01

    Full Text Available Este trabalho analisa a composição e a sazonalidade das espécies de moluscos potenciais hospedeiros intermediários de trematódeos digenéticos, bem como fornece informações a respeito das possíveis infecções por diplostomídeos nesta comunidade, em ambientes lênticos da planície de inundação do alto rio Paraná. Foram coletadas e analisadas dez espécies de moluscos, e houve nítida sazonalidade na densidade e abundância dos moluscos, correlacionada significativamente com a temperatura da água. Os maiores valores observados foram entre os meses de novembro de 2002 a fevereiro de 2003. Apenas Biomphalaria peregrina caracterizou-se como hospedeiro para Diplostomidae, pois nesta espécie foram encontradas 32 cercárias de Hysteromorpha triloba em março de 2003.This study analyzes the composition and seasonality of mollusk species as potential intermediate hosts for digenean trematodes, and also supplies information regarding the possible infections by diplostomidae in that community, in lentic environments of the upper Paraná river floodplain. Ten species of mollusks were collected and analyzed, with noticeable seasonality in the density and abundance of mollusks, significantly correlated with water temperature. The highest values observed were in the period between November 2002 and February 2003. Only Biomphalaria peregrina was characterized as a host for diplostomidae, given that 32 cercariae of Hysteromorpha triloba were found in this species in March 2003.

  10. Antischistosomal activity of ginger (Zingiber officinale) against Schistosoma mansoni harbored in C57 mice.

    Science.gov (United States)

    Mostafa, Osama M S; Eid, Refaat A; Adly, Mohamed A

    2011-08-01

    The repeated chemotherapy of schistosomiasis has resulted in the emergence of drug-resistant schistosome strains. The development of such resistance has drawn the attention of many authors to alternative drugs. Many medicinal plants were studied to investigate their antischistosomal potency. The present work aimed to evaluate antischistosomal activity of crude aqueous extract of ginger against Schistosoma mansoni. Sixteen mice of C57 strain were exposed to 100 ± 10 cercariae per mouse by the tail immersion method; the mice were divided into two groups: untreated group and ginger-treated one. All mice were sacrificed at the end of 10th week post-infection. Worm recovery and egg counting in the hepatic tissues and faeces were determined. Surface topography of the recovered worms was studied by scanning electron microscopy. Histopathological examination of liver and intestine was done using routine histological procedures. The worm burden and the egg density in liver and faeces of mice treated with ginger were fewer than in non-treated ones. Scanning electron microscopical examination revealed that male worms recovered from mice treated with ginger lost their normal surface architecture, since its surface showed partial loss of tubercles' spines, extensive erosion in inter-tubercle tegumental regions and numerous small blebs around tubercles. Histopathological data indicated a reduction in the number and size of granulomatous inflammatory infiltrations in the liver and intestine of treated mice compared to non-treated mice. The results of the present work suggested that ginger has antischistosomal activities and provided a basis for subsequent experimental and clinical trials.

  11. Isolation and preservation of schistosome eggs and larvae in RNAlater® facilitates genetic profiling of individuals

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    Webster Bonnie L

    2009-10-01

    Full Text Available Abstract Although field-sampling procedures to capture gDNA from individual schistosome larval stages directly from their natural hosts exist, they do pose some technical and logistical challenges hampering certain epidemiological studies. The aim of this study was to develop, refine and evaluate an alternative methodology, which enables better preservation of large numbers of individual schistosome larval stages and eggs collected in low resource endemic areas, to provide PCR-quality DNA for multi-locus genetic analysis. The techniques reported here present simple and effective short-term field and long-term laboratory preservation and storage systems for individually sampled schistosome eggs and larval stages using a commercially available aqueous stabilisation reagent, RNAlater® eliminating the need for more cumbersome resources such as refrigerators, heaters and centrifuge equipment for immediate specimen processing. Adaptations to a general gDNA extraction method are described, that enables the acquisition of a gDNA extract (~50 μl, facilitating multiple molecular analyses of each sampled schistosome. The methodology provided PCR-quality mitochondrial and nuclear DNA from laboratory cercariae, miracidia and eggs that had been stored at up to 37°C for 2 weeks and at 4°C for 6 months and also from field collected samples. This present protocol provides significant epidemiological, ethical and practical advantages over existing sampling methods and has the potential to be transferred to studies on other organisms, especially where specimens are unable to be seen by the naked eye, are difficult to handle and need to be obtained from a field environment.

  12. Developmental expression analysis and immunolocalization of a biogenic amine receptor in Schistosoma mansoni

    Science.gov (United States)

    El-Shehabi, Fouad; Vermeire, Jon J.; Yoshino, Timothy P.; Ribeiro, Paula

    2013-01-01

    A Schistosoma mansoni G-protein coupled receptor (SmGPCR) was previously cloned and shown to be activated by the biogenic amine, histamine. Here we report a first investigation of the receptor’s subunit organization, tissue distribution and expression levels in different stages of the parasite. A polyclonal antibody was produced in rabbits against the recombinant third intracellular loop (il3) of SmGPCR. Western blot studies of the native receptor and recombinant protein expressed in HEK293 cells showed that SmGPCR exists both as a monomer (65 kDa) and an apparent dimer of ≈130 kDa These species were verified by immunoprecipitation of SmGPCR from S. mansoni extracts, using antibody that was covalently attached to agarose beads. Further investigation determined that the SmGPCR dimer was resistant to treatment with various detergents, 4 M urea and 0.1 M DTT but could be made to dissociate at acidic pH, suggesting the dimer is non-covalent in nature. Confocal immunofluorescence studies revealed significant SmGPCR immunoreactivity in sporocysts, schistosomula and adult worms but not miracidia. SmGPCR was found to be most widely expressed in the schistosomula, particularly the tegument, the subtegumental musculature and the acetabulum. In the adult stage we detected SmGPCR immunofluorescence mainly in the tubercles of male worms and, to a lesser extent, the body wall musculature. Localization in sporocysts was mainly confined to the tegument and cells within parenchymal matrices. A realtime quantitative reverse-transcription PCR analysis revealed that SmGPCR is upregulated at the mRNA level in the parasitic stages compared to the free-living miracidium and cercariae, and it is particularly elevated during early sporocyst and schistosomula development. The results identify SmGPCR as an important parasite receptor with potential functions in muscle and the tegument of S. mansoni. PMID:19545530

  13. The effects of temperature and light on the survival, development, and infectivity of Plagiorchis elegans eggs.

    Science.gov (United States)

    Zakikhani, M; Rau, M E

    1998-12-01

    Plagiorchis elegans eggs were incubated at 0, 4, 10, 20, or 30 C under a 12-hr:12-hr (L:D) photoperiod for 120 days. Approximately one-quarter of the eggs had already initiated the process of embryonation when passed with the feces of the hamster (Mesocricetus auratus), the experimental definitive host. Eggs failed to embryonate at 0 C and died within 2 days. Incubation at 4 C allowed full embryonation, but the mean number of embryonated eggs per day (1.32+/-0.15) and the mean number of eggs available over the course of incubation (egg days) (219.00+/-2.24) remained low. These values increased progressively as incubation temperatures rose and reached levels of 3.59+/-0.30 and 1,467.50+/-4.56, respectively, at 20 C. Although incubation at 30 C further increased the mean number of eggs per day (5.45+/-0.56), the mean number of egg days declined sharply to 735.25+/-4.71, suggesting that elevated temperatures enhanced embryonation but lowered the survival of embryonated eggs. This was also reflected in the infectivity of eggs over time. Embryonated eggs incubated at 10 and 20 C remained infective significantly longer than eggs incubated at higher or lower temperatures. Incubation in constant light yielded significantly lower mean numbers of embryonated eggs per day (1.86+/-0.09) and mean number of egg days (96.25+/-0.99) than incubation in constant darkness (2.23+/-0.17 and 701.50+/-2.86 eggs, respectively) but did not affect the infectivity of embryonated eggs. The data suggest that at moderate temperatures and shielded from light, fully embryonated eggs of P. elegans may survive in the aquatic environment for a period of months. Such eggs may serve as a source of infection for populations of Stagnicola elodes and ensure the sustained production of the highly entomopathogenic cercariae required for mosquito control. PMID:9920308

  14. A loop-mediated isothermal amplification (LAMP assay for early detection of Schistosoma mansoni in stool samples: a diagnostic approach in a murine model.

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    Pedro Fernández-Soto

    2014-09-01

    Full Text Available Human schistosomiasis, mainly due to Schistosoma mansoni species, is one of the most prevalent parasitic diseases worldwide. To overcome the drawbacks of classical parasitological and serological methods in detecting S. mansoni infections, especially in acute stage of the disease, development of cost-effective, simple and rapid molecular methods is still needed for the diagnosis of schistosomiasis. A promising approach is the loop-mediated isothermal amplification (LAMP technology. Compared to PCR-based assays, LAMP has the advantages of reaction simplicity, rapidity, specificity, cost-effectiveness and higher amplification efficiency. Additionally, as results can be inspected by the naked eye, the technique has great potential for use in low-income countries.A sequence corresponding to a mitochondrial S. mansoni minisatellite DNA region was selected as a target for designing a LAMP-based method to detect S. mansoni DNA in stool samples. We used a S. mansoni murine model to obtain well defined stool and sera samples from infected mice with S. mansoni cercariae. Samples were taken weekly from week 0 to 8 post-infection and the Kato-Katz and ELISA techniques were used for monitoring the infection. Primer set designed were tested using a commercial reaction mixture for LAMP assay and an in house mixture to compare results. Specificity of LAMP was tested using 16 DNA samples from different parasites, including several Schistosoma species, and no cross-reactions were found. The detection limit of our LAMP assay (SmMIT-LAMP was 1 fg of S. mansoni DNA. When testing stool samples from infected mice the SmMIT-LAMP detected S. mansoni DNA as soon as 1 week post-infection.We have developed, for the first time, a cost-effective, easy to perform, specific and sensitive LAMP assay for early detection of S. mansoni in stool samples. The method is potentially and readily adaptable for field diagnosis and disease surveillance in schistosomiasis-endemic areas.

  15. 2-Cys peroxiredoxins from Schistosoma japonicum: the expression profile and localization in the life cycle.

    Science.gov (United States)

    Kumagai, Takashi; Osada, Yoshio; Kanazawa, Tamotsu

    2006-10-01

    Peroxiredoxin (Prx) is known to be an antioxidant protein that protects the organisms against various oxidative stresses and functions as a signal transductor. Here, we determined the full-length cDNA sequences of three types of Prx from an Asian blood fluke, Schistosoma japonicum: Prx-1, Prx-2 and Prx-3. According to the deduced amino acid sequences, only Prx-3 had a mitochondria-targeting sequence. Using RT-PCR, it was shown that these Prx genes were constitutively expressed in the eggs, cercariae and adult worms of the schistosome. Western blot analysis using antisera specific for each Prx revealed that all the three Prx proteins existed in these developmental stages. By immunolocalization analysis, Prx-1 existed on the surface of a miracidium and in the space between a miracidium and an eggshell. Furthermore, Prx-1 was deposited in the host tissues around the eggs. In adult worms, Prx-1 was not only expressed in the tegument, but also contained in their excretory/secretory products. The surface of the 7 day-schistosomula was stained with anti-Prx-1 antiserum. On the other hand, Prx-2 only existed inside the miracidia in eggs. In addition, Prx-2 was mainly detected in the sub-tegumental tissues, parenchyma, vitelline gland and gut epithelium of the adult worms, but was not detected in the tegument of adults and schistosomula. Taken together with previous reports by other investigators, these data suggest that Prx-1 acts to protect the parasite against the ROS produced by host immune cells, and that Prx-2 plays important roles in intracellular redox signaling and/or in the reduction of ROS generated through the hemoglobinolytic process in the digestive tract. PMID:16806527

  16. Schistosomiasis vaccine development: progress and prospects

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    Bergquist NR

    1998-01-01

    Full Text Available The undisputed, worldwide success of chemotherapy notwithstanding, schistosomiasis continues to defy control efforts in as much rapid reinfection demands repeated treatment, sometimes as often as once a year. There is thus a need for a complementary tool with effect for the longer term, notably a vaccine. International efforts in this direction have been ongoing for several decades but, until the recombinant DNA techniques were introduced, antigen production remained an unsurmountable bottleneck. Although animal experiments have been highly productive and are still much needed, they probably do not reflect the human situation adequately and real progress can not be expected until more is known about human immune responses to schistosome infection. It is well-known that irradiated cercariae consistently produce high levels of protection in experimental animals but, for various reasons, this proof of principle cannot be directly exploited. Research has instead been focussed on the identification and testing of specific schistosome antigens. This work has been quite successful and is already at the stage where clinical trials are called for. Preliminary results from coordinated in vitro laboratory and field epidemiological studies regarding the protective potential of several antigens support the initiation of such trials. A series of meetings, organized earlier this year in Cairo, Egypt, reviewed recent progress, selecteded suitable vaccine candidates and made firm recommendations for future action including pledging support for large-scale production according to good manufacturing practice (GMP and Phase I trials. Scientists at the American Centers for Disease Control and Prevention (CDC have drawn up a detailed research plan. The major financial support will come from USAID, Cairo, which has established a scientific advisory group of Egyptian scientists and representatives from current and previous international donors such as WHO, NIAID, the

  17. Post-splenectomy infections in chronic schistosomiasis as a consequence of bacterial translocation

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    Kedma de Magalhães Lima

    2015-06-01

    Full Text Available INTRODUCTION : Bacterial translocation is the invasion of indigenous intestinal bacteria through the gut mucosa to normally sterile tissues and internal organs. Schistosomiasis may cause alterations in the immune system and damage to the intestines, portal system and mesenteric lymph nodes. This study investigated bacterial translocation and alterations in the intestinal microbiota and mucosa in schistosomiasis and splenectomized mice. METHODS : Forty female 35-day-old Swiss Webster mice were divided into the following four groups with 10 animals each: schistosomotic (ESF, splenectomized schistosomotic (ESEF, splenectomized (EF and control (CF. Infection was achieved by introduction of 50 Schistosoma mansoni (SLM cercariae through the skin. At 125 days after birth, half of the parasitized and unparasitized mice were subjected to splenectomy. Body weights were recorded for one week after splenectomy; then, the mice were euthanized to study bacterial translocation, microbiota composition and intestinal morphometry. RESULTS : We observed significant reductions in the weight increases in the EF, ESF and ESEF groups. There were increases of at least 1,000 CFU of intestinal microbiota bacteria in these groups compared with the CF. The EF, ESF and ESEF mice showed decreases in the heights and areas of villi and the total villus areas (perimeter. We observed frequent co-infections with various bacterial genera. CONCLUSIONS : The ESEF mice showed a higher degree of sepsis. This finding may be associated with a reduction in the immune response associated with the absence of the spleen and a reduction in nutritional absorption strengthened by both of these factors (Schistosoma infection and splenectomy.

  18. Dynamics of Infected Snails and Mated Schistosoma Worms within the Human Host

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    G. Besigye-Bafaki

    2005-01-01

    Full Text Available Male and female worms are independently distributed within a human host each with a Poisson probability distribution mass function. Mating takes place immediately when partners are available. It was found that the mated worm function is non-linear near the origin and becomes almost linear as the worms increase. They increase with increase in the worm load due to aggregation of worms. This also increases the infection of snails which are secondary hosts. On the analysis of the model, three equilibrium states were found, two of which were stable and one unstable. A stable endemic equilibrium within a community is very much undesirable. So the main objective of the model was to have the point O(0,0 as the only equilibrium point. This is a situation where there are no worms within the human host and the environment is free of infected snails. A critical point, above which the disease would be chronic and below which the disease would be eradicated, was found and analyzed. The parameters indicated that to achieve a disease free environment, the death rate of worms within the human host should be much greater than the cercariae that penetrate the human. Also the death rate of infected snails should be much higher than the contact rate between the miracidia and the snails. It was concluded that de-worming and killing of snails should be emphasized for disease control and educating the masses on the modes of disease transmission is quite necessary for prevention of the disease.

  19. Infectivity and development of Opisthorchis viverrini metacercariae in immunosuppressed Barbonymus gonionotus fingerlings (Cyprinidae).

    Science.gov (United States)

    Donthaisong, Chalermlap; Arunsan, Patpicha; Suwannatrai, Kulwadee; Prasopdee, Sattrachai; Kulsantiwong, Jutharat; Wongmaneeprateep, Sutee; Suwannatrai, Apiporn; Tesana, Smarn

    2016-10-01

    Opisthorchiasis caused by Opisthorchis viverrini infection, is a serious public health problem in Lao PDR, Cambodia, Vietnam and Thailand. Cyprinid fish are required for the transmission of O. viverrini metacercariae to fish eating-mammal hosts including humans. The transmission of infective metacerariae is an important event, potentially resulting in the development of cholangiocarcinoma in cases of chronic opisthorchiasis. For a better understanding of the development of O. viverrini metacercariae in the second intermediate host, Barbonymus gonionotus (Cyprinidae), the immune response of infected B. gonionotus through fibrous tissue formation and superoxide dismutase (SOD) activity were investigated. The immunosuppressant (prednisolone) was administered to B. gonionotus infected with O. viverrini cercariae to study infectivity and development of the metacercariae. Additionally, the effects of prednisolone were studied by the investigation of fibrous tissue formation around the metacercariae, as well as SOD activity. In our study, prednisolone administered prior to infection in B. gonionotus had higher metacercarial recovery when compared to the non-administered control group. On the other hand, the administration of prednisolone after the O. viverrini infection allowed metacercariae to develop to the infective stage. Energy consumption from encystation to the infective stage required 443.9-463.7degree-days. The results show that immunosuppression decreases fibrous tissue and SOD activity in infected fish, and also affects the ability of O. viverrini metacercariae to develop to the infective stage. The immune response to metacercarial development of O. viverrini in cyprinid fish should be further studied to gain a greater understanding of this process, and hence, a better understanding of the mechanism(s) involved in metacercarial wall formation. PMID:27338181

  20. Generation of a Novel Bacteriophage Library Displaying scFv Antibody Fragments from the Natural Buffalo Host to Identify Antigens from Adult Schistosoma japonicum for Diagnostic Development.

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    Christopher G Hosking

    2015-12-01

    Full Text Available The development of effective diagnostic tools will be essential in the continuing fight to reduce schistosome infection; however, the diagnostic tests available to date are generally laborious and difficult to implement in current parasite control strategies. We generated a series of single-chain antibody Fv domain (scFv phage display libraries from the portal lymph node of field exposed water buffaloes, Bubalus bubalis, 11-12 days post challenge with Schistosoma japonicum cercariae. The selected scFv-phages showed clear enrichment towards adult schistosomes and excretory-secretory (ES proteins by immunofluorescence, ELISA and western blot analysis. The enriched libraries were used to probe a schistosome specific protein microarray resulting in the recognition of a number of proteins, five of which were specific to schistosomes, with RNA expression predominantly in the adult life-stage based on interrogation of schistosome expressed sequence tags (EST. As the libraries were enriched by panning against ES products, these antigens may be excreted or secreted into the host vasculature and hence may make good targets for a diagnostic assay. Further selection of the scFv library against infected mouse sera identified five soluble scFv clones that could selectively recognise soluble whole adult preparations (SWAP relative to an irrelevant protein control (ovalbumin. Furthermore, two of the identified scFv clones also selectively recognised SWAP proteins when spiked into naïve mouse sera. These host B-cell derived scFvs that specifically bind to schistosome protein preparations will be valuable reagents for further development of a cost effective point-of-care diagnostic test.

  1. Inhibitory effects of prostaglandin E1 on activation of hepatic stellate cells in rabbits with schistosomiasis

    Institute of Scientific and Technical Information of China (English)

    Wei-Long Zou; Zhen Yang; Yun-Jin Zang; Dong-Jian Li; Zhi-Peng Liang; Zhong-Yang Shen

    2007-01-01

    BACKGROUND:Liver ifbrosis is the result of an imbalance between synthesis and degradation of extracellular matrix proteins of the liver. At the cellular and molecular levels, this progressive process is mainly characterized by activation of hepatic stellate cells (HSCs). Schistosoma japonica is one of the most prevalent causes of liver ifbrosis in China. It is characterized by hepatocyte damage, inlfammation, and chronic parasite egg-induced granuloma formation leading to ifbrosis. This study aimed to investigate the inhibitory effects of prostaglandin E1 (PGE1) on activation of HSCs and the alteration of type Ⅰ and Ⅲ collagen in rabbits with schistosomiasis. The study may promote the clinical application of praziquantel and PGE1 as a combined therapy to reverse hepatic ifbrosis caused by schistosomiasis. METHODS: Rabbits were percutaneously infected with cercaria of S. japonicum. Seven rabbits were subjected to intravenous injections of PGE1 (2.5 μg/kg daily) from days 60 to 120 after infection. The ultrastructural changes in activated HSCs were observed under transmission electron microscopy. The expression ofα-smooth muscle actin (α-SMA) was detected by immunohistochemistry. Fibril-forming collagens were detected by picrosirius staining. RESULTS: Activation of HSCs was a characteristic alteration in schistosome-induced hepatic ifbrosis. The expression of contraction-related α-SMA and the content of collagens were increased. Exogenous PGE1 markedly inhibited the activation of HSCs and reduced the expression of α-SMA around the hepatic sinusoids (P CONCLUSIONS:Activation of HSCs may play a key role in the progress of schistosome-induced hepatic ifbrosis. PGE1 effectively protects rabbit liver from ifbrosis, at least in part by inhibiting the activation of HSCs.

  2. Endocannabinoids Anandamide and Its Cannabinoid Receptors in Liver Fibrosis after Murine Schistosomiasis

    Institute of Scientific and Technical Information of China (English)

    Hongyan LIU; Xiao GAO; Ruixian DUAN; Qiao YANG; Yaowen ZHANG; Yongwei CHENG; Yan GUO; Wangxian TANG

    2009-01-01

    This study examined endogenous cannabinoid (ECB)-anandamide (AEA) and its can-nabinoid receptors (CBR) in mice liver with the development of schistosomajaponicum.Mice were infected with schistosoma by means of pasting the cercaria onto their abdomens.Liver fibrosis was pathologically confirmed nine weeks after the infection.High performance liquid chromatography (HPLC) was employed to determine the concentration of AEA in the plasma of mice.Immunofluorescence was used to detect the expression of CBR 1 and CBR2 in liver tissue.Morphological examination showed typical pathological changes,with worm tubercles of schistosoma deposited in the liver tissue,fibrosis around the worm tubercles and infiltration or soakage ofinfiammatory cells.Also,CBRI and CBR2 were present in hepatocytes and hepatic sinusoids of the two groups,but they were obviously enhanced in the schistosoma-infected mice.However,the average optical density of CBR1 in the negative control and fibrosis group was 13.28±7.32 and 30.55±7.78,and CBR2 were 28.13±6.42 and 52.29±4.24 (P<0.05).The levels of AEA in the fibrosis group were significantly increased as compared with those of the control group.The concentrations of AEA were (0.37±0.07) and (5.67±1.34) ng/mL (P<0.05).It is concluded that the expression of endocannabinoids AEA and its cannabinoid receptor CBR were significantly increased in schistosoma-infected mice.Endogenous endocannabinoids may be involved in the development of schistosoma-induced liver fibrosis.

  3. A role for CD4 sup + but not CD8 sup + T cells in immunity to Schistosoma mansoni induced by 20 krad-irradiated and Ro 11-3128-terminated infections

    Energy Technology Data Exchange (ETDEWEB)

    Vignali, D.A.A.; Bickle, Q.D.; Taylor, M.G. (London School of Hygiene and Tropical Medicine (UK)); Crocker, P. (Oxford Univ. (UK). Sir William Dunn School of Pathology); Cobbold, S.; Waldmann, H (Cambridge Univ. (UK). Dept. of Pathology)

    1989-08-01

    The role of CD4{sup +} (L3/T4{sup +}) and CD8{sup +} (Lyt-2{sup +}) T cells in immunity to Schistosoma mansoni induced by 20 krad-irradiated and Ro 11-terminated infections in mice was investigated directly by in vivo depletion of these subsets with cytotoxic rat monoclonal antibodies (mAb). Effective physical depletion was demonstrated by flow cytometric analysis and immunohistochemical staining. Functional depletion of helper activity following anti-CD4 treatment was indicated by an abrogation of concanavalin A(Con A)-induced colony-stimulating factor (CSF) release, while anti-CD8 treatment had no effect in these assays. Pre-existing S. mansoni-specific antibody levels were unaffected by anti-CD4 and anti-CD8 treatment. In vivo depletion of CD4 {sup +} T cells resulted in a dramatic reduction in immunity induced by one (up to 100%) and two (up to 70%) vaccinations with 20 krad-irradiated cercariae and also of resistance induced by Ro 11-attenuated infections (up to 100%). Depletion of CD8{sup +} T cells had no effect on resistance induced by any of the vaccination protocols investigated. A correlation was observed between resistance and T cell-induced, macrophage-mediated killing of schistosomula in vitro, both of which were abrogated following anti-CD4 treatment but were unaffected by CD8{sup +} T-cell depletion. The possible role of CD4{sup +} T cells in vivo and the implications for vaccine development are discussed. (author).

  4. Modulation of expression and activity of cytochrome P450s and alteration of praziquantel kinetics during murine schistosomiasis

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    Mara A Gotardo

    2011-03-01

    Full Text Available In this study, we investigated the expression and activity of liver cytochrome P450s (CYPs and praziquantel (PZQ kinetics in mice infected with Schistosoma mansoni. Swiss Webster (SW mice of both genders were infected (100 cercariae on postnatal day 10 and killed on post-infection days (PIDs 30 or 55. Non-infected mice of the same age and sex served as controls. Regardless of mouse sex, infection depressed the activities of CYP1A [ethoxy/methoxy-resorufin-O-dealkylases (EROD/MROD], 2B9/10 [pentoxy/benzyloxy-resorufin-O-dealkylases (PROD, BROD], 2E1 [p-nitrophenol-hydroxylase (PNPH] and 3A11 [erythromycin N-demethylase (END] on PID 55 but not on PID 30. On PID 55, infection decreased liver CYP mRNA levels (real-time reverse transcription-polymerase chain reaction. On PID 30, whereas mRNA levels remained unaltered in males, they were depressed in females. Plasma PZQ (200 and 400 mg/kg body weight intraperitoneally levels were measured (high-performance liquid chromatography at different post-treatment intervals. In males and females, infection delayed the PZQ clearance on PID 55, but not on PID 30. Therefore, it can be concluded that schistosomiasis down-modulated CYP expression and activity and delayed PZQ clearance on PID 55, when a great number of parasite eggs were lodged in the liver. On PID 30, when egg-laying was initiated by the worms, no change of CYP expression and activity was found, except for a depression of CYP1A2 and 3A11 mRNAs in female mice.

  5. Diagnostic accuracy and applicability of a PCR system for the detection of Schistosoma mansoni DNA in human urine samples from an endemic area.

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    Martin Johannes Enk

    Full Text Available Schistosomiasis caused by Schistosoma mansoni, one of the most neglected human parasitoses in Latin America and Africa, is routinely confirmed by microscopic visualization of eggs in stool. The main limitation of this diagnostic approach is its lack of sensitivity in detecting individual low worm burdens and consequently data on infection rates in low transmission settings are little reliable. According to the scientific literature, PCR assays are characterized by high sensitivity and specificity in detecting parasite DNA in biological samples. A simple and cost effective extraction method for DNA of Schistosoma mansoni from urine samples in combination with a conventional PCR assay was developed and applied in an endemic area. This urine based PCR system was tested for diagnostic accuracy among a population of a small village in an endemic area, comparing it to a reference test composed of three different parasitological techniques. The diagnostic parameters revealed a sensitivity of 100%, a specificity of 91.20%, positive and negative predictive values of 86.25% and 100%, respectively, and a test accuracy of 94.33%. Further statistical analysis showed a k index of 0.8806, indicating an excellent agreement between the reference test and the PCR system. Data obtained from the mouse model indicate the infection can be detected one week after cercariae penetration, opening a new perspective for early detection and patient management during this stage of the disease. The data indicate that this innovative PCR system provides a simple to handle and robust diagnostic tool for the detection of S. mansoni DNA from urine samples and a promising approach to overcome the diagnostic obstacles in low transmission settings. Furthermore the principals of this molecular technique, based on the examination of human urine samples may be useful for the diagnosis of other neglected tropical diseases that can be detected by trans-renal DNA.

  6. Unusual snail species involved in the transmission of Fasciola hepatica in watercress beds in central France

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    Dreyfuss G.

    2002-06-01

    Full Text Available Four freshwater pulmonate species (Lymnaea ovata, L. stagnalis, Physa acuta, Planorbis leucostomawere living in several watercress beds known for their relationships with human cases of fasciolosis, whereas L. truncatula was never found. The aims of these studies were to determine the prevalence of natural infections with Fasciola hepatica in snails and to verify if these species might ensure the full larval development of this trematode (with cercarial shedding] when they were experimentally subjected to F. hepatica only, or to co-infections with an other trematode species. Investigations were so carried out in six snail populations living in watercress beds (including three for P. acuta and in four others originating from three brooks or a pond (as controls. Snails naturally infected with F. hepatica were found in two watercress beds inhabited by L. ovata (prevalence of infection: 1.4 % and P. leucostoma (0.1 %, respectively. The L. ovata from the watercress bed could be infected at a higher size than those from the control population and the prevalence of this infection was greater in the bed population. Similar findings were noted for L. stagnalis. Despite single or dual infections, the results obtained with the four populations of P. acuta were unsuccessful. In contrast, the co-infections of young P. leucostoma with Paramphistomum daubneyi and F. hepatica resulted in the shedding of some F. hepatica cercariae. According to the authors, the occurrence of fasciolosis in these watercress beds would be the consequence of frequent natural encounters between parasite and snails (L. ovata, L. stagnalis, or of co-infections with P. daubneyi and F. hepatica (P. leucostoma. In watercress beds only colonized by P. acuta, a lymnaeid species would have ensured the larval development of F. hepatica but it would have been eliminated by P. acuta, as this last species was known to be invasive and could colonize open drainage ditches on siliceous soil.

  7. Diversification of Schistosoma japonicum in Mainland China revealed by mitochondrial DNA.

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    Qin Ping Zhao

    Full Text Available BACKGROUND: Schistosoma japonicum still causes severe parasitic disease in mainland China, but mainly in areas along the Yangtze River. However, the genetic diversity in populations of S. japonicum has not been well understood across its geographical distribution, and such data may provide insights into the epidemiology and possible control strategies for schistosomiasis. METHODOLOGY/PRINCIPAL FINDINGS: In this study infected Oncomelania snails were collected from areas in the middle and lower (ML reaches of the Yangtze River, including Hubei, Hunan, Anhui, Jiangxi and Jiangsu provinces, and in the upper reaches of the river, including Sichuan and Yunnan provinces in southwest (SW China. The adult parasites obtained from experimentally infected mice using isolated cercariae were sequenced individually for several fragments of mitochondrial regions, including Cytb-ND4L-ND4, 16S-12S and ND1. Populations in the ML reaches exhibited a relatively high level of diversity in nucleotides and haplotypes, whereas a low level was observed for populations in the SW, using either each single fragment or the combined sequence of the three fragments. Pairwise analyses of F-statistics (Fst revealed a significant genetic difference between populations in the ML reaches and those in the SW, with limited gene flow and no shared haplotypes in between. It is rather obvious that genetic diversity in the populations of S. japonicum was significantly correlated with the geographical distance, and the geographical separation/isolation was considered to be the major factor accounting for the observed difference between populations in the ML reaches and those in the SW in China. CONCLUSIONS: S. japonicum in mainland China exhibits a high degree of genetic diversity, with a similar pattern of genetic diversity as observed in the intermediate host snails in the same region in China.

  8. 叶巢外睾吸虫感染钉螺对钉螺体内日本血吸虫发育的影响%Studies on Antagonism between Exorchis ovariolobularis and Schistosoma japonicum in Oncomelania hupensis

    Institute of Scientific and Technical Information of China (English)

    叶向群

    2001-01-01

    目的探讨在日本血吸虫中间宿主湖北钉螺体内叶巢外睾吸虫和日本血吸虫的对抗性.方法通过叶巢外睾吸虫和日本血吸虫对湖北钉螺的双重感染,计算血吸虫的感染率和尾蚴逸出量,常规石蜡切片观察钉螺组织学变化.结果钉螺在感染血吸虫37 d后再感染外睾吸虫,经一定时间后检查发现,血吸虫的感染率为52.9%,显著低于同时单独感染日本血吸虫对照组的感染率(75.9%);先感染叶巢外睾吸虫,经10、32、60、100和120 d不同的时间间隔后再感染日本血吸虫的钉螺,血吸虫感染率分别为64%、66.7%、65.2%、56.4%和57.1%,而单独感染日本血吸虫对照组钉螺血吸虫感染率为90.5%,经统计检验,各双重感染实验组血吸虫与对照组的感染率间差异具有显著或非常显著性意义(P《0.05或P《0.01).对各试验组及对照组钉螺逸出尾蚴试验发现,试验组钉螺血吸虫尾蚴逸出量均显著低于对照组的逸出量.组织学观察发现各双重感染组钉螺消化腺萎缩,消化腺盲囊间隙只有少量血吸虫子胞蚴,血吸虫子胞蚴皱缩、变形及不规则,且子胞蚴中只含稀疏的尾蚴胚球,有的子胞蚴中已无胚球;而单独感染血吸虫的对照组中血吸虫均发育到成熟的子胞蚴或尾蚴.结论钉螺体内叶巢外睾吸虫和日本血吸虫之间存在一定的对抗性,而叶巢外睾吸虫在这种对抗中占优势.%Objective To examine the antagonistic interactions between Schistosoma japonicum and Exorchis ovariolobularis in the snail host, Oncomelania hupensis. Methods The infection rate and average number of cercariae of S.japonicum were examined in O. hupensis which had been suverinfected with S.japonicum and E. ovariolobularis. The experimental snails were histologically observed by paraffin section. Results When snails were fed with eggs of E. ovariolobularis 37 days later than S.japonicum infection, the infection rate of S .japonicum (52

  9. Investigation on the Hosts with Natural Paragonimus Infection and Species Identification in Jinhua Prefecture of Zhejiang Province%浙江省金华地区并殖吸虫自然宿主调查及虫种鉴定

    Institute of Scientific and Technical Information of China (English)

    楼宏强; 胡野; 金耀建; 余新图; 王岚; 何旭英; 屠平光

    2011-01-01

    Objective To investigate the natural hosts infected with Paragonimus sp. And identify the species of the parasite in selected counties/districts of Jinhua prefecture in Zhejiang Province. Methods Three townships/towns were randomly sampled from each of the 9 counties/districts in Jinhua as pilot spots for the survey. Fresh-water snails were collected from the fields for examining cercariae. Crabs were collected and detected for metacercariae by routine technique and the metacercariae were fed to dogs purchased in areas free from paragonimiasis. Fecal materials of dogs and cats around the villages and streams where crabs were found infected were collected for examining eggs. The artificially infected dogs were sacrificed 55 d after infection to receive adult worms. The size of cercariae, metacercariae, eggs and adult worms was measured. After the DNA of the adult worm was extracted, PCR was used to amplify the COI gene and ITS2 gene of the mitochondria from the worms. Homology with relative strains/isolates was analyzed and phylo-genetic tree constructed. Results The survey demonstrated that the snail Semisulcospira libertina and the crab Sinopotamon chekiangense served as the first and second intermediate hosts respectively. Natural infection was found in Wucheng District with an infection rate of 0.2% (2/1 088) in snails and 76.7% (46/60) in crabs in Shafan township, and an infection index (II) of 2.0 in crabs, 0.1% (1/1 683) in snails and 53.0% (46/60) in crabs with an II of 0.9 inLangya town. The infection rate was 0 (0/575) in snails and 30.0% (18/60) in crabs with an II of 0.1 in Baimu township of Wuyi County. Paragonimus eggs were detected in feces of stray cats with a positive rate of 8.3% (1/12) in Shafan and 0.6% (1/17) in Langya. The size and morphology of the cercariae, metacercariae, eggs and adult worms were similar to those of Paragonimus westermani. The sequences of the COI and ITS2 genes were with 390 bp and 363 bp respectively, indicating a

  10. Ensaios preliminares do Guaiacum officinale L. como moluscicida Preliminary tests of Guaiacum officinale L. as molluscicide

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    Nelymar Martineli Mendes

    1993-12-01

    Full Text Available Suspensões aquosas do pericarpo do fruto, da casca da raiz, das folhas e das sementes de Guaiacum officinale foram testadas como moluscicida, cercaricida e piscicida em diferentes concentrações. Em laboratório, a suspensão do pericarpo do fruto apresentou 100% de mortalidade a 100 ppm para desovas de B. glabrata, a 20 ppm para caramujos adultos de Biomphalaria glabrata, B. straminea e B. tenagophila, a 5 ppm para Lebistes reticulatus (peixes e a 1 ppm para cercárias de Schistosoma mansoni. O extrato etanólico do pericarpo do fruto não foi ativo para caramujo adulto de B. glabrata. As doses letais para 90% dos caramujos adultos (DL90, após 24 horas de exposição, usando a suspensão do pericarpo do fruto foram de: 15 ppm para B. glabrata; 14 ppm para B. straminea e 18 ppm para B. tenagophila. As DL90 das suspensões das casca da raiz, sementes e folhas contra B. glabrata foram de 57, 33 e 15 ppm, respectivamente. No campo, coma suspensão do pericarpo do fruto a mortalidade de caramujos adultos de B. glabrata foi de 68% a 20 ppm e 100% a 40 ppmAqueous suspensions of fruit's pericarp, leaves, root's bark and seeds of Guaiacum officinale were tested at different concentrations as molluscicide, cercaricide and piscicide. In the laboratory the suspension of fruit's pericarp produced 100% mortality for egg masses of B. glabrata at 100 ppm, for adult snails of Biomphalaria glabrata, B. straminea and B. tenagophila at 20 ppm, for Lebistes reticulatus (fishes at 5 ppm and Schistosoma mansoni's cercariae at 1 ppm. The ethanolic extract of fruit's pericarp was not active against adult snails of B. glabrata. The letal dose for adult snails(DL90 of the aqueous suspension of fruit's pericarp after 24 hours exposure, were: 15 ppm for B. glabrata; 14 ppm for B. straminea and 18 ppm for B. tenagophila. The DL90 of aqueous suspensions of root's bark, seeds and leaves were 57 ppm, 33 ppm and 15 ppm, respectively. In the field, B. glabrata adult snail

  11. Scanning electron microscope observation on tegumental damage of 21-d-old Schistosoma japonicum induced by praziquantel%吡喹酮对21-d日本血吸虫童虫皮层损害的扫描电镜观察

    Institute of Scientific and Technical Information of China (English)

    肖树华; 沈炳贵

    1995-01-01

    AIM: To study the effect of praziquantel (Pra) on the tegument of 21-d-old schistosomula, mice infected with Schistosoma japonicum cercariae for 21 d were treated ig with Pra at a single dose. METHOD: Groups of mice were killed at different intervals within 48 h, and the worms were collected by perfusion for scanning electron microscopic observation. RESULTS: When the dose used was moderate swelling, fusion or even erosion and collapsed of the tegumental ridges, which was characterized by swelling of the discoid sensory structures. At higher dose of 500 mg were seen, but more extensive and serious.d, severe swelling, erosion and peeling of the tegument accompanied by the attachment of the host leukocytes on the damaged surface were seen. CONCLUSION: Pra exhibited a direct killing effect on 21-d-old schistosomula.%目的:观察吡喹酮对21-d童虫皮层的作用.方法:小鼠于感染日本血吸虫尾蚴达21 d时,ig1剂吡喹酮,并在治疗后1-48 h的不同时间内剖杀取虫,作扫描电镜观察.结果:吡喹酮的剂量为300 mg·kg-1时,宿主体内的21-d童虫示有轻度或中度的皮层褶嵴肿胀、融合、糜烂或破溃,且以盘状感觉器的肿胀为特征.用吡喹酮的较高剂量500 mg·kg-1治疗,虫的体表亦有相似的变化,但较广泛和严重.若每dig吡喹酮500 mg·kg-1,连给3 d,则虫的皮层严重肿、糜烂和剥落,并伴有宿主的白细胞附着.结论:结果表明,吡喹酮对21-d童虫有直接杀死作用.

  12. Evolution of sarcoma 180 (ascitic tumor in mice infected with Schistosoma mansoni

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    Fausto Edmundo Lima Pereira

    1986-03-01

    Full Text Available Mice infected with 60 cercariae of Schistosoma mansoni were more resistant to the sarcoma 180 ascites tumor. Tumor inoculation was performed 50 days after schistosoma infection and the animals were observed and weighed at 48 hours intervals for development and progression of malignancy. In infected mice the weight gain (ascites formation started later and was shorter than in uninfected Controls. Also, the number of tumor cells into the peritoneal cavity 72h after tumor implantation was shorter in infected group than incontrols. This in creased resistance against a transplantable tumor probably is related to the effect of endotoxin on tumoricidal activity of macrophages activated by the infection. The immunodepression induced by Schistosoma mansoni infection enhances the proliferation of endogenous bacteria increasing the amount of endotoxin absorbed from the gut.Camundongos infectados com 60 cercárias de Schistosoma mansoni tomaram-se mais resistentes ao sarcoma 180 na forma de tumor ascítico. A inoculação das células tumorais foi feita no 50º dia de infecção e a evolução do tumor foi acompanhada através dapesagem dos animais com intervalos de 48 horas. Nos camundongos infectados o ganho de peso (formação da ascite começou mais tarde e foi menor do que nos controles não infectados. Também o número de células tumorais na cavidade peritoneal 72 horas após a implantação do tumor foi menor no grupo infectado. Este aumento de resistência a um tumor transplantávelpossivelmente está relacionado ao efeito de endotoxinas sobre a atividade tumoricida dos macrofagos ativados pela infecção. A imunossupressão induzida pela infecção favorece a proliferação de bactérias da flora endógena aumentando a quantidade de endotoxinas absorvidas pelo intestino.

  13. 日本血吸虫感染鼠巨噬细胞IL-13Rα2的表达%Expression on IL-13Rα2 in macrophages of Schistosoma japonicum-infected mice

    Institute of Scientific and Technical Information of China (English)

    王维; 郑胜生; 祁瑶; 闻惠琴; 刘丽丽; 沈继龙

    2011-01-01

    目的 检测IL-13的诱骗受体IL-13Rα2在血吸虫病巨噬细胞的表达,为从细胞水平探讨Th2型免疫性疾病分子病理机制奠定基础.方法 建立日本血吸虫病鼠模型,采用免疫荧光标记法分别检测肝肉芽肿和原代巨噬细胞IL-13Rα2蛋白的表达情况.结果 荧光显微镜下观察:肝肉芽肿内可见似"咖啡豆样"散在分布的IL-13Rα2免疫阳性信号,巨噬细胞膜内缘呈异常增强的环状荧光.结论 巨噬细胞是IL-13Rα2阳性表达细胞,IL-13Rα2是血吸虫病重要的免疫病理调节分子.%The purpose of this study was to investigate the expression on intracellular proteins of IL-13Rα2 in the macrophages of Schistosomiasis japonicum mice, and to offer the experiment foundation for elucidating IL-13 responding cell and mechanism of fibrogenesis in Th2-mediated diseases. A large number of mice were exposed to cercariae and established S. japonicum mouse model. IL-13Rα2 expressed in the granulomas of liver tissues and peritoneal macrophages was determined by immunofluorescent labeling with primary antibody of goat anti-mouse IL-13Rα2 antibody and monoclonal anti-CD68 antibody,respectively. Coffee bean-like IL-13Rα2 positive staining was showed in the hepatic granuloma in fluorescentmicroscopy. Co-expression of IL-13Rα2 and CD68 protein in peritoneal macrophages from 8-week infected mice was observed. It exhibited the distribution of IL-13Rα2 in cytoplasm concentrated on the inner layer of membrane in macrophages. It's suggested that IL-13Rα2 expressing macrophages might be a critical contributor to the immunopathogenesis of schistosomiasis.

  14. Atividade quimioprofilática na esquistossomose mansoni de sabonetes contendo óleo essencial de frutos de Pterodon pubescens Chemoprophylactic activity in schistosomiasis mansoni of soaps containing essential oil from the fruits of Pterodon pubescens

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    Naftale Katz

    1993-04-01

    Full Text Available Foi estudada a ação quimioprofilática na esquistossomose experimental do óleo essencial do fruto de Pterodon pubescens Benth (Leguminosae, incorporado a diferentes formulações de sabonete. As formulações foram usadas topicamente nas caudas de camundongos que, imediatamente, 24,72 ou 168 horas após, foram expostos a cercárias de Schistosoma mansoni, pelo método de imersão da cauda. A proteção foi avaliada 45 dias após a exposição, quando os camundongos foram sacrificados e os vermes recolhidos por perfusão. Os resultados mostraram níveis de proteção variando de 0,0 a 100% conforme a formulação usada. Foi também desenvolvida uma metodologia que possibilitou a avaliação do sabonete protetor quando camundongos foram expostos à infecção natural em córregos infestados com caramujos na periferia de Belo Horizonte, MG. Resultados promissores foram obtidos, uma vez que houve proteção de 57,5 e 31,1% quando os animais foram ensaboados 24 e 48 horas antes. Estudos preliminares de avaliação de irritação e toxicidade foram favoráveis e mostraram que esta nova arma profilática poderá auxiliar no controle da esquistossomose.The chemoprophylactic action of the essential oil of the fruit of Pterodon pubescens Benth (Leguminosae, incorpored in different soap formulations, was studied in experimental schistosomiasis. The formulations were used locally on the tails of mice which were exposed to Schistosoma mansoni cercariae immediately, 24, 72 or 168 hours later by the method of tail immersion. Protection was evaluated 45 days after exposure when the mice were sacrificed and the worms collected by perfusion. The results showed levels of protection varying from 0.0 to 100% depending on the formulation used. A methodology that allowed the evaluation of soap protection of mice exposed to natural infection in snail infested streams on the outskirts of Belo Horizonte, MG, was also developed. Promising results were obtained in that

  15. Phage displaying peptides mimic schistosoma antigenic epitopes selected by rat natural antibodies and protective immunity induced by their immunization in mice

    Institute of Scientific and Technical Information of China (English)

    Min Wang; Xin-Yuan Yi; Xian-Ping Li; Dong-Ming Zhou; McReynolds Larry; Xian-Fang Zeng

    2005-01-01

    AIM: To obtain the short peptides mimic antigenic epitopes selected by rat natural antibodies to schistosomes, and to explore their immunoprotection against schistosomiasis in mice.METHODS: Adults worm antigens (AWA) were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked transferred immunoblotting methods with normal SD rat sera (NRS). The killing effects on schistosomula with fresh and heat-inactivated sera from SD rats were observed. Then the purified IgG from sera of SD rats was used to biopan a phage random peptide library and 20 randomly selected positive clones were detected by ELISA and 2 of them were sequenced.Sixty female mice were immunized thrice with positive phage clones (0, 2nd, 4th wk). Each mouse was challenged with 40 cercariae, and all mice were killed 42 d after challenge. The worms and the liver eggs were counted. RESULTS: NRS could specifically react to the molecules of 75 000, 47 000, 34 500 and 23 000 of AWA. Sera from SD rats showed that the mortality rate of schistosomula was 76.2%, and when the sera were heat-inactivated in vitro, the mortality rate was decreased to 41.0% after being cultured for 48 h. The specific phages bound to IgG were enriched about 300-folds after three rounds of biopanning. Twenty clones were detected by ELISA, 19 of them bound to the specific IgG of rat sera. Immunization with these epitopes was carried out in mice. Compared with the control groups, the mixture of two mimic peptides could induce 34.9% (P = 0.000) worm reduction and 67.6% (P = 0.000) total liver egg reduction in mice. Two different mimic peptides could respectively induce 31.0% (P = 0.001), 14.5% (P = 0.074) worm reduction and 61.2% (P = 0.000), 35.7% (P = 0.000) total liver egg reduction. The specific antibody could be induced by immunization of the mimic peptides, and the antibody titer in immunized mice reached more than 1:6 400 as detected by ELISA.CONCLUSION: Specific peptides mimic antigenic

  16. 日本血吸虫反式剪接前导RNA的鉴定%Identification and Characterization of an mRNA Trans-splicing Leader in Schistosoma Japonicum

    Institute of Scientific and Technical Information of China (English)

    李锐; 贺亮; 郝力力

    2012-01-01

    RNA trans-splicing occurs in a wide range of eukaryotes, from protozoa to chordates. To investigate the SL RNA-mediated trans-splicing in the zoonotic trematode Schistosoma japonicum, a spliced-leader (SL) RNA was cloned in adults using race. The 36-nucleotide SL in S. Japonicum was derived from a 90-nucleotide nonpolyadenylylated RNA transcript encoded by 55 copies of SL genes dispersed in the genome confirmed by blot and real time PCR. Differential transcription patterns of the SL gene in the parasite developmental stages were observed using real time PCR. Predominant expression of SL RNA was found in the two developmental stages, egg and cercariae. Expression of SL RNA transcripts in female was the least. No significant expression difference between male and schistosomulum (3 d and 14 d) was observed. In summary, trans-splicing of spliced leader might acted as an important mechanism of post-transcriptional gene regulation in S. Japonicum.%RNA反式剪接现象广泛存在于真核生物中,包括单细胞原虫以及低等脊索动物.为鉴定日本血吸虫中是否存在SL RNA介导的反式剪接,运用Race方法从成虫中克隆出了1个90 nt的SL RNA基因,36 nt的RNA前导序列正是来源于此90 nt的无PolyA结构的SL RNA,并通过Northern进一步证实了该基因的存在.同时采用荧光定量和Southern对其拷贝数、基因组上的分布方式以及虫体不同阶段的表达量进行了鉴定,发现SL RNA具有55个拷贝并在基因组上呈散在分布;在虫卵和尾蚴时期SL RNA基因的转录丰度最高,雌虫阶段最低,雄虫、3天童虫以及14天童虫阶段无明显差别.结果表明,SL RNA介导的反式剪接可能是日本血吸虫基因转录后重要的调控机制之一.

  17. Antischistosomal activity of acridanone- hydrazones in Cebus monkeys experimentally infected with the SJ strain of Schistosoma mansoni

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    Paulo Marcos Zech Coelho

    1995-09-01

    Full Text Available In this study, four compounds were utilized at the dose of 12.5mg/kg body weight, p.o., to treat Cebus monkeys experimentally infected with about 200 cercariae of Schistosoma mansoni (SJ strain, via transcutaneous route. The oograms performed with rectal snips, as well as stool examinations carried out periodically, showed no viable eggs of the parasite, from day 29 to 226post-treatment. The perfusion undertaken after killing the animals showed absence of worms in the treated monkeys, whereas 83 worms were recovered from the control, thus corroborating the results obtained by means of oograms and coproscopy. These results confirm the efficacy of 9-acridanone- hydrazones previously tested against the LE strain of S. mansoni. The low curative dose and apparent absence of toxicity render these dmgs an important therapeutic reserve, taking into consideration the reports on the resistance of S. mansoni to the modern drugs oxamniquine and praziquantel.No presente trabalho, quatro compostos foram utilizados na dose de 12,5mg/kg de peso, por via oral, em macacos infectados transcutaneamente com cerca de 200 cercárias de Schistosoma mansoni. Os oogramas realizados com fragmentos de mucosa retal e os exames de fezes realizados, periodicamente, demonstraram a ausência de ovos viáveis do parasito a partir do 29- até o 226a dia pós-tratamento. A perfusão, apôs sacrifício dos animais tratados, não detectou vermes, enquanto que do macaco cotztrole 83 vermes foram recuperados, confirmando assim os resultados dos oogramas e da coproscopia. Estes resultados confirmam a eficácia das 9-acridanonas- hydrazonas já observada anteriormente contra a cepa LE de S. mansoni. A baixa dosagem curativa e aparente ausência de toxicidade colocam estas drogas como uma reserva terapêutica importante, tendo em vista o relato de resistência do S. mansoni às drogas modernas oxamniquína e praziquantel.

  18. Molecular Characterization of the Schistosoma mansoni Zinc Finger Protein SmZF1 as a Transcription Factor

    Science.gov (United States)

    D'Astolfo, Diego S.; Cardoso, Fernanda C.; Rajão, Matheus A.; Mourão, Marina M.; Gava, Elisandra; Oliveira, Sérgio C.; Macedo, Andréa M.; Machado, Carlos R.; Pena, Sérgio D. J.; Kitten, Gregory T.; Franco, Glória R.

    2009-01-01

    Background During its development, the parasite Schistosoma mansoni is exposed to different environments and undergoes many morphological and physiological transformations as a result of profound changes in gene expression. Characterization of proteins involved in the regulation of these processes is of importance for the understanding of schistosome biology. Proteins containing zinc finger motifs usually participate in regulatory processes and are considered the major class of transcription factors in eukaryotes. It has already been shown, by EMSA (Eletrophoretic Mobility Shift Assay), that SmZF1, a S. mansoni zinc finger (ZF) protein, specifically binds both DNA and RNA oligonucleotides. This suggests that this protein might act as a transcription factor in the parasite. Methodology/Principal Findings In this study we extended the characterization of SmZF1 by determining its subcellular localization and by verifying its ability to regulate gene transcription. We performed immunohistochemistry assays using adult male and female worms, cercariae and schistosomula to analyze the distribution pattern of SmZF1 and verified that the protein is mainly detected in the cells nuclei of all tested life cycle stages except for adult female worms. Also, SmZF1 was heterologously expressed in mammalian COS-7 cells to produce the recombinant protein YFP-SmZF1, which was mainly detected in the nucleus of the cells by confocal microscopy and Western blot assays. To evaluate the ability of this protein to regulate gene transcription, cells expressing YFP-SmZF1 were tested in a luciferase reporter system. In this system, the luciferase gene is downstream of a minimal promoter, upstream of which a DNA region containing four copies of the SmZF1 putative best binding site (D1-3DNA) was inserted. SmZF1 increased the reporter gene transcription by two fold (p≤0.003) only when its specific binding site was present. Conclusion Taken together, these results strongly support the hypothesis

  19. Epidemiology and control of intestinal schistosomiasis on the Sesse Islands, Uganda: integrating malacology and parasitology to tailor local treatment recommendations

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    Fenwick Alan

    2010-07-01

    Full Text Available Abstract Background Intestinal schistosomiasis is often widespread among the populations living around Lake Victoria and on its islands. The Sesse Island group (containing some 84 islands, however, is typically assumed to be a low prevalence zone, with limited transmission, but has never been surveyed in detail. Here, we present a rapid mapping assessment, bringing together snail and parasite information, at 23 sites for the presence of intermediate host snails and at 61 sites for the prevalence of intestinal schistosomiasis in school-aged children (N = 905. Two different diagnostic tools were used and compared at 45 of these sites: Kato-Katz thick faecal smears and circulating cathodic antigen (CCA urine dipsticks. Results Biomphalaria snails were found at 11 sites but in low numbers; none was found shedding schistosome cercariae. At 22 out of the 45 sites, local prevalence by urine and/or stool diagnostics was in excess of 50%, although mean prevalence of intestinal schistosomiasis overall was 34.6% (95% confidence intervals (CI = 31.0-38.3% by Kato-Katz and 46.5% (95% CI = 42.7-50.4% by CCA if 'trace' reactions were considered infection-positive (if considered infection-negative, mean prevalence was 28.1% (95% CI = 24.7-31.7%. Diagnostic congruence between CCA and Kato-Katz was poor and significant discordance in estimated prevalence by location was found, with each often inferring different mass drug administration regimes. Conclusions Accurate estimation of schistosome prevalence is important for determining present and future treatment needs with praziquantel; the wide range of schistosome prevalence across the Sesse Island group requires a treatment regime largely tailored to each island. In high prevalence locations, further malacological sampling is required to confirm the extent of local transmission, especially on the northern islands within the group. The observation that different diagnostic tests can provide varying results in

  20. Comportamento da cepa LE de Schistosoma mansoni, após passagem em hospedeiro humano infectado acidentalmente

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    Neusa Araújo

    1986-12-01

    Full Text Available Uma auxiliar de laboratório infectou-se acidentalmente, com cercárias de Schistosoma mansoni, cepa LE, mantida rotineiramente em nossos laboratórios. Decorridos 5 meses, o exame parasitológico de fezes revelou 108 ovos/g . A pacientefoi tratada com oxamniquine, porém a infecção continuou ativa (6 ovos/g. Foi então obtido o isolado SSF mantido no modelo Biomphalaria glabrata - camundongo albino. Os resultados obtidos no estudo comparativo, entre o isolado SSF e a cepa LE, que lhe deu origem, mostraram que a duração do período pré-patente e o índice de infectividade em camundongos, bem como a resposta aos agentes esquistossomicidas (hycanthone, oxamniquine epraziquantel não apresentaram diferenças estatisticamente significativas. Por outro lado, o número de miracídios obtidos dos intestinos e fígados dos camundongos infectados foi o dobro com a cepa LE, quando comparados com aquele do isolado SSF. Também a variação do peso dos animais foi bastante diferente. Concluiu-se que apenas uma passagem pelo hospedeiro humano não mudou substancialmente as características da cepa estudada.A laboratory technician was accidentally infected with the LE strain of Schistosoma mansoni cercariae maintained in our laboratories. After 5 months infection parasitological examination revealed 108 eggs/g faeces. Althrough treated with oxamniquine, the infection still persisted (6 eggs/g of faeces. An isolate (SSF was obtained from that person and maintained in Biomphalaria glabrata - Swiss mouse by alternate passage. The experimental comparative results between the newly obtained SSF isolate and the original LE strain showed that the differences in pre-patent period, the mice infectivity level and the schistosomicidal response to hycanthone, oxamniquine and praziquantel was not statistically significant. On the other hand the number of miracidia recovered from intestines and livers of equally infected mice was twice as miich in the LE strain than

  1. Animal Host of Schistosoma japonicum and Transmission of Schistosomiasis in Poyang Lake Region

    Institute of Scientific and Technical Information of China (English)

    林丹丹; 刘跃民; 胡飞; 张绍基

    2003-01-01

    本文从鄱阳湖区洲滩野粪污染指数、实验流行病学研究及耕牛放牧、尾蚴分析和钉螺感染的季节性变化等方面阐明了鄱阳湖区日本血吸虫的主要动物宿主为耕牛,病牛(尤其是 3岁以下耕牛)为当地血吸虫病的主要传染源;分析了鄱阳湖区血吸虫传播特征,每年春季(4~6月),为血吸虫在终宿主(人和牛)和中间宿主相互传播的"交汇点";涨水季节(7~8月)为血吸虫非易感季节,秋季(9~10月)为人畜感染的高峰,冬季(11月~翌年 3月),为洲滩枯水期,血吸虫传播休止.终宿主和中间宿主的易感区域均为村旁的洲滩.%The article clarified, according to the recent research results which have been done in Poyang Lake region of Jiangxi province, bovines are the most important animal hosts of Schistosoma japonicum and infected bovines are main infectious sources of Schistosomiasis in Poyang Lake region. Spring (March to June) is the " cross transmission stage" between definitive host and intermediate host, that is, spring is not only the susceptible season of infection for livestock and human, but also is the susceptible season of infection for snails. In flood season (July to August), the transmission of Schistosomiasis between livestock and snails belong to " low level phase" . Autumn (September to Octber) is the second seasonal peak of cercariae and is the susceptible season of infection for livestock and human. Winter(November to Feburary in next year) is the non- susceptible season of infection. Most of the susceptible zones of infection for livestock, human and snails are the marshlands near the endemic villages.

  2. Paeoniflorin prevents hepatic fibrosis of Schistosomiasis japonica by inhibiting TGF-β1 production from macrophages in mice

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to investigate the effect of paeoniflorin (PAE)on hepatic fibrosis of mice with Schistosomiasis japonica in vivo and in vitro,a model of hepatic fibrosis caused by schistosomiasis was established in mice infected with cercariae of Schistosomajaponicum.Then,PAE was orally administered before and after praziquantel treatment and both therapeutics were given simultaneously at different time points after the infection.The concentration of serum hyaluronic acid(HA)was determined by radioimmunoassay(RIA).Hepatic granuloma and fibrosis were evaluated via HE and Masson staining.The expression of s-smooth muscle actin(α-SMA),transforming growth factor 131(TGF-β1)and collagen I(Col Ⅰ)protein was detected by immunohistochemistry.The effect of soluble egg antigen(SEA)and PAE on the production of TGF-131 from mouse peritoneal macrophages (PMφs)was investigated by RT-PCR,Western blotting and ELISA.The effect of TGF-β1 in optimum macrophage-conditioned medium(OPMCM)on the proliferation of hepatic stellate cells(HSCs)and collagen secretion from HSCs with anti-TGF-β1 antibody was explored by MTT assay and ELISA.The results show that PAE could significantly reduce the concentration of serum HA,the size of egg granuloma,the severity of hepatic fibrosis and the expression of α-SMA,TGF-β1 and Col I protein in the pre-treatment group.However,in sim-or post-treatment group,PAE did not have any significant therapeutic effect.TGF-β1 could be secreted from PMφs stimulated by SEA.Meanwhile,the production of TGF-β1 from PMφs could be depressed significantly by PAE in a concentration-dependent manner.TGF-β1 could promote the proliferation of HSCs and the secretion of collagens.In a word,PAE can prevent hepatic granuloma and fibrosis caused by schistosomiasis japonica through the inhibition of the secretion of TGF-β1 from PMφs,the proliferation and activation of HSCs and the secretion of collagens from HSCs.

  3. The influence of the regional basic diet from northeast Brazil on health and nutritional conditions of mice infected with Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Eridan M. Coutinho

    1992-03-01

    Full Text Available Protein nutritionalstatus indicators were studied in weanling albino Swiss mice infected with S. mansoni andfed the Regional Basic Diet (RBDfrom Northeast Brazil, a multideficient diet of low-protein content. Each mouse was infected percutaneously with 80 cercariae. The experiment lasted 63 days. The growth curve, food consumption, protein intake, weight gain, Protein Efficiency Ratio (PER and Net Protein Ratio (NPR were the parameters investigated. RBD-fed mice showed a marked weight loss, a lower food and protein intake, a slower body weight gain and lower rates of food protein utilization when compared to casein-fed animals. Differences between infected and non-infected mice were not consistent. The present results suggest that the effects of RBD-induced malnutrition on health and nutritional conditions of the mice are more severe than those of Manson's schistosomiasis, in the initial phase of the disease.Indicadores do estado nutrictional de proteínas foram estudados em camundongos albinos suíços recém- desmamados e infectados com S. mansoni, aos quais foi administrada a Dieta Básica Regional (DBR do Nordeste do Brasil. Cada camundongo foi infectado com 80 cercárias, por via percutânea. O experimento teve a duração de 63 dias. Os parâmetros investigados foram: evolução ponderai, consumo alimentar, ingestão protéica, ganho ponderai, Coeficiente de Eficiência Protéica (PER e Coeficiente de Eficiência Protéica Líquida (NPR. Os camundongos alimentados com a DBR revelaram acentuada perda de peso, menor consumo alimentar e protéico, maior lentidão no ganho em peso relacionado com a fase de crescimento e taxas menos elevadas de utilização da proteína dietética, quando comparados com os controles (alimentados com dieta balanceada, à base de 22,60% de caseína. As diferenças encontradas entre camundongos infectados e não infectados, não foram consistentes. Os resultados sugerem que os efeitos provocados pela m

  4. Parasitological and malacological surveys reveal urogenital schistosomiasis on Mafia Island, Tanzania to be an imported infection.

    Science.gov (United States)

    Stothard, J Russell; Ameri, Haji; Khamis, I Simba; Blair, Lynsey; Nyandindi, Ursuline S; Kane, Richard A; Johnston, David A; Webster, Bonnie L; Rollinson, David

    2013-11-01

    To confirm the local endemicity of Schistosoma haematobium on Mafia Island, Tanzania, conjoint parasitological and malacological surveys were undertaken in July 2006 with parasitological investigations supplemented with case-history questionnaires. A total of 238 children (125 girls and 113 boys, mean age of 13.9 years) across 9 primary schools were examined. The prevalence of micro-haematuria and egg-patent infection was 18.1% (CI95=9.6-33.6) and 4.2% (CI95=1.9-7.6), respectively but a strong female bias was observed for micro-haematuria (5.6F:1M) contrasting with a strong male bias for the presence of eggs (1F:4M). All egg-patent infections were of light-intensity (<10eggs/10ml). No clear associations between infection prevalence and local water-contact, by school, were found and all 10 of the egg-positive children had a travel history to the nearby mainland or Zanzibar. Inspection of community diagnostic registers at Kilindoni Hospital revealed a low proportion (<2%) of egg-patent infection for 20,306 samples tested in the 2000-2005 period. A total of 43 freshwater sites, a third of which were previously sampled in 1999 and 2002, were surveyed and 11 species of freshwater mollusc were found. Four species of Bulinus (B. nasutus, B. forskalii, B. barthi and B. sp.) were encountered across 13 sites with B. nasutus restricted to 3 of these towards the north of the island. No collected snail was observed to shed schistosome cercariae. Further characterisation of B. nasutus and S. haematobium included infection challenge on two occasions, with miracidia obtained from egg-patent children from Mafia and Unguja islands as well as DNA barcoding of snails and schistosomes. B. nasutus was shown refractory to infection. With the substantial travel to and from Mafia, the refractory nature of local snails and evidence from DNA barcoding in schistosomes and snails, we conclude that urogenital schistosomiasis is an imported infection. PMID:23010161

  5. Effect of ozonide OZ418 against Schistosoma japonicum harbored in mice.

    Science.gov (United States)

    Xue, Jian; Wang, Xiaofang; Dong, Yuxiang; Vennerstrom, Jonathan L; Xiao, Shu-hua

    2014-09-01

    The in vitro and in vivo efficacies of ozonide carboxylic acid OZ418 against Schistosoma japonicum were investigated. For in vitro experiments, juvenile (14-day-old) and adult schistosomes were collected from mice infected with 80-100 S. japonicum cercariae for 14 and 35 days post-infection and the worms were maintained in Roswell Park Memorial Institute (RPMI) 1640 supplemented by 10% calf serum. Against 35-day-old adult S. japonicum, OZ418 resulted in weakened worm motor activity, injury to the worm body, emergence of vacuoles along the worm surface, and death. A similar outcome was seen in 14-day-old juvenile S. japonicum exposed to OZ418. Ineffective concentrations (1, 5, and 10 μg/mL) of OZ418 also interacted with hemin to significantly increase the killing effect against adult schistosomes. The LC50 value of OZ418 against juvenile (14-day-old) and adult schistosomes were identical--16.2 μg/mL, whereas the corresponding LC95 values were 30.7 and 22.7 μg/mL, respectively. Treatment of adult and juvenile (14-day-old) S. japonicum-infected mice with single 200-400-mg/kg oral doses of OZ418 produced total worm burden reductions of 68.5-84.1 and 37.5-50.9%, respectively. Further study showed that in mice infected with various stages of schistosomes and treated with a single oral OZ418 400 mg/kg, poor efficacy was seen in the 3-h-old juvenile worm group, while 14-day-old and 21-day-old juvenile worm groups exhibited less efficacy with total worm burden reductions of 42.6-52.4%. On the other hand, similar and higher total worm burden reductions (64.2-76.0%) were seen in the 7-day-old juvenile worm group and 28-day-old as well as 35-day-old adult worm groups. Furthermore, the mean worm burden reductions of the 7-day-old juvenile worm group and 35-day-old adult worm group were statistically significantly higher than that of the 14-day-old or 21-day-old juvenile worm group (P < 0.01 or <0.05). These data suggest that OZ418 has promising efficacy against 7-day

  6. Glycomic Analysis of Life Stages of the Human Parasite Schistosoma mansoni Reveals Developmental Expression Profiles of Functional and Antigenic Glycan Motifs.

    Science.gov (United States)

    Smit, Cornelis H; van Diepen, Angela; Nguyen, D Linh; Wuhrer, Manfred; Hoffmann, Karl F; Deelder, André M; Hokke, Cornelis H

    2015-07-01

    Glycans present on glycoproteins and glycolipids of the major human parasite Schistosoma mansoni induce innate as well as adaptive immune responses in the host. To be able to study the molecular characteristics of schistosome infections it is therefore required to determine the expression profiles of glycans and antigenic glycan-motifs during a range of critical stages of the complex schistosome lifecycle. We performed a longitudinal profiling study covering schistosome glycosylation throughout worm- and egg-development using a mass spectrometry-based glycomics approach. Our study revealed that during worm development N-glycans with Galβ1-4(Fucα1-3)GlcNAc (LeX) and core-xylose motifs were rapidly lost after cercariae to schistosomula transformation, whereas GalNAcβ1-4GlcNAc (LDN)-motifs gradually became abundant and predominated in adult worms. LeX-motifs were present on glycolipids up to 2 weeks of schistosomula development, whereas glycolipids with mono- and multifucosylated LDN-motifs remained present up to the adult worm stage. In contrast, expression of complex O-glycans diminished to undetectable levels within days after transformation. During egg development, a rich diversity of N-glycans with fucosylated motifs was expressed, but with α3-core fucose and a high degree of multifucosylated antennae only in mature eggs and miracidia. N-glycan antennae were exclusively LDN-based in miracidia. O-glycans in the mature eggs were also diverse and contained LeX- and multifucosylated LDN, but none of these were associated with miracidia in which we detected only the Galβ1-3(Galβ1-6)GalNAc core glycan. Immature eggs also exhibited short O-glycan core structures only, suggesting that complex fucosylated O-glycans of schistosome eggs are derived primarily from glycoproteins produced by the subshell envelope in the developed egg. Lipid glycans with multifucosylated GlcNAc repeats were present throughout egg development, but with the longer highly fucosylated

  7. Do schistosome vaccine trials in mice have an intrinsic flaw that generates spurious protection data?

    Science.gov (United States)

    Wilson, R Alan; Li, Xiao-Hong; Castro-Borges, William

    2016-01-01

    The laboratory mouse has been widely used to test the efficacy of schistosome vaccines and a long list of candidates has emerged from this work, many of them abundant internal proteins. These antigens do not have an additive effect when co-administered, or delivered as SWAP homogenate, a quarter of which comprises multiple candidates; the observed protection has an apparent ceiling of 40-50%. We contend that the low level of maturation of penetrating cercariae (~32% for Schistosoma mansoni) is a major limitation of the model since 68/100 parasites fail to mature in naïve mice due to natural causes. The pulmonary capillary bed is the obstacle encountered by schistosomula en route to the portal system. The fragility of pulmonary capillaries and their susceptibility to a cytokine-induced vascular leak syndrome have been documented. During lung transit schistosomula burst into the alveolar spaces, and possess only a limited capacity to re-enter tissues. The acquired immunity elicited by the radiation-attenuated (RA) cercarial vaccine relies on a pulmonary inflammatory response, involving cytokines such as IFNγ and TNFα, to deflect additional parasites into the alveoli. A principal difference between antigen vaccine protocols and the RA vaccine is the short interval between the last antigen boost and cercarial challenge of mice (often two weeks). Thus, after antigen vaccination, challenge parasites will reach the lungs when both activated T cells and cytokine levels are maximal in the circulation. We propose that "protection" in this situation is the result of physiological effects on the pulmonary blood vessels, increasing the proportion of parasites that enter the alveoli. This hypothesis will explain why internal antigens, which are unlikely to interact with the immune response in a living schistosomulum, plus a variety of heterologous proteins, can reduce the level of maturation in a non-antigen-specific way. These proteins are "successful" precisely because they

  8. Changes of the Levels of Blood NO and TNF-α Concentrations in Water Buffaloes and Goats Infected with Fasciola hepatica

    Institute of Scientific and Technical Information of China (English)

    WANG Bing-yun; CHEN Long; MAO Xin-zhi; GU You-fang; Gonzalez-Gallego j

    2003-01-01

    Changes of concentrations were studied in water buffaloes and goats infected with Fasciola he-patica on blood NO(nitric oxide) and TNF-α(tumor necrosis factor-α). Twenty healthy male castrated waterbuffaloes of 2 - 3 years old and weighing 300 - 500 kg as well as six goats were confirmed free of fasciolosis byfecal examination and Dot-ELISA. Two studies were conducted using the water buffaloes. In the first experi-ment, 8 water buffaloes were randomly divided into control group (n=3) and infection group (n=5). Eachbuffalo in the infected group received orally 60 metacercariae of F. hepatica per day for 20 days (total 1 200metacercariae) to produce a chronic infection. In the second experiment, 12 water buffaloes were randomly di-vided into infected (n=9) and control group (n=3). Each buffalo in the infected group was given a singleoral dose of 1 600 metacercariae to produce an acute infection. The 6 goats were randomly divided into two in-fected groups and a control group. The sheep in two infections received a single oral dose of 200 and 500 meta-cercariae respectively, the control group remained uninfected. Blood NO and TNF-α concentrations of the testanimals were measured by a reductive enzyme assay and RIA, respectively. Blood NO concentration in bothacutely and chronically infected water buffaloes progressively increased from week 3 post-infection and was sig-nificantly greater than that of the control group (P<0.05) at the 5th week (acute infection) and 7th week(chronic infection), and remaining at higher concentration for the remaining period of the studies. BloodTNF-αt concentrations in both chronically and acutely infected water buffaloes also increased after infection. Inthe goat experiment, plasma NO concentrations in both infection groups increased from week 3 after infection,and remained higher than that of the control group until the end of the experiment. TNF-α concentrations ingoats in infection group 1 and 2 gradually increased after

  9. Evidence Suggesting that Fasciola gigantica Might be the Most Prevalent Causal Agent of Fascioliasis in Northern Iran

    Directory of Open Access Journals (Sweden)

    K Ashrafi

    2004-10-01

    Full Text Available Following the occurrence of two large outbreaks in Gilan province, northern Iran, the public health importance of human fascioliasis has increased significantly. The mixed infections of Fasciola gigantica and F. hepatica within a given domestic animal individual suggest a very complicate picture of possible circulation ways of the parasite and the possibility for humans to be infected with both species. Elucidating these circulation ways is very critical for understanding the epidemiology and transmission of the disease and being ascertain how animals and humans enter the different liver fluke circulations in this endemic zone. The main objective of the present study was to investigate the distribution and natural infections of local lymnaeids, environmental characteristics related to the disease transmission and determining the most prevalent fasciolids and definitive hosts in human endemic areas of Gilan province. Bandar-Anzali and Rasht are the most important endemic areas with most of the cases of human disease during the epidemics and inter-epidemic periods. Sheep raising is not normal in these regions, while cattle is the most common definitive host. According to the data obtained from slaughterhouse observations in Bandar-Anzali and Rasht, the main fasciolid in local cattle is F. gigantica. Of 928 adult liver flukes collected from 13 infected livers of cattle, in Rasht and Bandar-Anzali slaughterhouses, 91.1% were diagnosed as F. gigantica and 8.9% as F. hepatica. L. gedrosiana and L. palustris were the most prevalent lymnaeid snails in this endemic zone. It appears that L. truncatula is not prevalent in Bandar-Anzali and Rasht and surroundings of these endemic cities. Of 4830 different snails studied, only seven L. gedrosiana were found to be infected with larval stages (rediae and cercariae of Fasciola sp. Experimental infections of 15 common laboratory mice by metacercariae, obtained from those naturally infected snails, were carried

  10. Epidemic distribution of Paragonimus in northern suburban of Guangzhou%广州北部山区并殖吸虫流行分布现状初步研究

    Institute of Scientific and Technical Information of China (English)

    陆予云; 乔亚峰; 沈浩贤; 邝浩成; 刘巧; 赵太平; 龙小山; 罗健留; 冼少龙; 傅广华

    2011-01-01

    In order to investigate the distribution of Paragonimus in northern suburban of Guangzhou, snails and crabs were collected from mountain streams and the cercariae and metacercariae of Paragonimus were detected and dissected. Cats and dogs were artificially infected with the metacercariae of Paragonimus from infected crabs, as results, the adult worms of Paragonimus were detected from these cats and dogs. The COI and ITS2 sequence analysis were performed in the adult worm samples, and the sequence results were compared with those of Paragonimus sequence in GenBank. It was found that for snail samples in Liangkou, Nankun Mountain and Lvtian areas, the average infection rates of cercariae were 0.32% (4/1,210), 0.15% (3/2,000) and 0. 03% (1/310) . The snail species in both Liangkou and Nankun Mountain areas were identified as Semisulcospira libertine, while the snail species in Lvtian area was Tricula. ;for crab samples in Liangkou area, the average infection rate of P. westermani metacercariae was 100% (35/35), and the crab species were identified as Sinopotamon pinheense. T he average numbers of the metacercariae in per crab and per gram of crab were 79.4 and 11.12, respectively. The highest numbers of metacercariae in one crab was 1 050. And for crab samples in Nankun Mountain area, the average infection rate of P. westermani metacercariae was also 100% (59/59), and the crab species were also identified as Sinopotamon pinheense. The average numbers of the metacercariae in per crab and per gram of crab were 105.66 and 7.87, respectively. For crab samples in Lvtian area, the average infection rate of Pagumogonimus skrjabini was 36.73% (36/98), and the crab species were identified as Nanhaipotomon pinyuanense. The average numbers of the metacercariae in per crab and per gram of crab were 4.55 and 0.53, respectively. The DNA sequences for COI and ITS2 from the adult worms of P. westermani from the Liangkou and Nankun Mountain areas detected 99%, 98% and

  11. 粤北山区并殖吸虫流行分布现状初步研究%Epidemiological survey of Paragonimus in northern Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    傅广华; 邓文强; 刘巧; 陆予云; 李旭文; 陈少华; 李宏光; 王萌

    2012-01-01

    目的 了解粤北地区并殖吸虫流行分布现状.方法 采集并解剖每处调查点山溪中螺蛳及溪蟹,查找并殖吸虫尾蚴和囊蚴.以所获囊蚴人工感染猫、犬,解剖猫、犬查找并殖吸虫成虫.取成虫样本,与GenBank里并殖吸虫的COI基因与ITS2基因序列比对,进行基因序列分析.结果 里东、叟里元、下洞河、太坪和小坑5处调查点溪蟹三平正并殖吸虫囊蚴感染率分别为74.54﹪ (41/53)、68.91﹪ (32/47)、77.77﹪(24/32) 、76.92﹪ (40/52)和81.5% (22/27),溪蟹物种均鉴定为平和华溪蟹.与GenBank三平正并殖吸虫基因序列比对,5处成虫样本COI基因同源性分别为99.5%、100%、99.5%、99.5%和100%,ITS2基因同源性为100%.大洞调查点的螺蛳检出并殖吸虫短尾尾蚴,感染率为0.058% (1/1,700),螺蛳物种鉴定为放逸短沟蜷,溪蟹检出卫氏并殖吸虫囊蚴,感染率为38.09%(32/84),溪蟹物种亦鉴定为平和华溪蟹.大洞成虫样本COI基因与卫氏并殖吸虫同源性100%,ITS2基因与卫氏并殖吸虫同源性99.5%.结论 粤北地区新发现三平正并殖吸虫高度疫源地5处,第二中间宿主为平和华溪蟹.5处疫源地虫种间无差异.卫氏并殖吸虫高度疫源地1处,第一中间宿主为放逸短沟蜷,第二中间宿主为平和华溪蟹.%The objective is to determine the epidemiological distribution of Paragonimus in northern Guangdong Province . Cercariae and metacercariae of Paragonimus were isolated from freshwater snails and crabs , and randomly collected at each study sites in northern Guangdong Province . Adult worms were obtained from experimentally infected cats and dogs . The gene sequences of cytochrome c oxidase subnnit 1 (COI) and second internal transcribed spacer (ITS2) region from adult worms were aligned with those of Paragonimus spp. deposited in GenBank database . Infection rates for the metacercariae of Euparagonimus cenocopiosus in Sinopotamonpinheense recorded at five of the six

  12. Biomphalaria straminea no Peru e sua suscetibilidade a cepas brasileiras de Schistosoma mansoni

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    C.A. Cuba Cuba

    1977-12-01

    species has notbeen described before in Peru. Progeny from these specimens tested for susceptíbility to the BH and SJ strains of Schistosoma mansoni which under natural conditions develop in B. glabrata of Belo Horizonte and B. tenagophila of São José dos Campos, respectively. Eighty specimens were exposed to the BH strain of which 13 or 16.2% devetoped infection with secondary sporocysts. However no elimination of cercariae was observed even in a specimen which lived 88 days after exposure. No spontaneous cure was found in this batch. Of 40 B. strami nea exposed to strain SJ, 9 or 22.5% became infected but only two eliminated a few cercariae on two consecutive days at 57 and 77 days after exposure. One died and one underwent spontaneous cure. In two other infected snails in which infection was visible through the shell spontaneous cure was noted. Serial histological sections of 9 snails were made after individual exposure to 50 miracidia of the BH strain and fixed 6-120 hours after exposure. These showed sporocysts in development and invaded by amebocytes without forming granutomas in the host tissues, demonstra ting the snails were susceptible. The population studied behaved experimental/y in a manner similar to other populations of B. straminea tested in the laboratory in that a low susceptibility was demonstra ted. However this does not exclude the possibility that this species could maintain the parasitic cycle in its area of distribution.

  13. Comportamento experimental de amostras de Schistosoma mansoni em relação às formas clínicas de esquistossomose: I. Estudo em camundongos Experimental behavior of samples of Schistosoma mansoni in relation to clinical forms of schistosomiasis: I. Study in mice

    Directory of Open Access Journals (Sweden)

    Mario José da Conceição

    1986-03-01

    ção da doença.Twenty isolates of Schistosoma mansoni were obtained from patients, all males 13 to 30 years old, autochtonous from the Village of Capitão Andrade, municipality of Itanhomi, state of Minas gerais, where an evolutive study of Manson's schistosomiasis is being performed since 1973. The isolates came from six patients with schistosome-infections (type I0, six with the hepato-instestinal form (type Ii, and eight with the hepaoesplenic form (type III. Each isolate was inoculated in mice divided in three groups of 16, exposed to 25, 50 and 100 cercariae, respectively. Controls were 12 uninfected mice. After 90 days adult worms were recovered from the portal by perfusion, from four mice of each experimental groups. Mice dying at various intervals and half of the rest f mice in each group sacrificed on the 90th and the 180th days were studied according to the following parameters: 1 weight of liver, spleen, lung and instestine; 2 egg count in the small intestine (proximal and medial and large intestine (distal. The average numbers of worms obtained by perfusion from groups I, II and III were 21.9%, 22% and 17.8% respectively. The average natural mortality rates of mice submitted to infection with 25,50 and 100 cercariae were, respectively, 12.4%, 23.2% and 40.2% for group I,4.7%, 19.5% and 22.2% for group II and 11.4%, 29.5% and 41.6% for group III, being therefore proportional to the inocula. The weight of the organs of the infected animals and the number of S. mansoni eggs was always proportional to the inoculum and the highest number of eggs were found in the median and proximal portion of the intestines in all three groups. The conclusion was the following: there was no correlation between the clinical forms of schistosomiasis and the behaviour of the isolates of S. mansoni in mice, the parasitological alternations being proportional to the inoculum used and the duration of the infection.

  14. Immunoprotection of SjP14 DNA vaccine against Schistosoma japonicum infection in mice%日本血吸虫调宁蛋白样蛋白P14基因疫苗对小鼠免疫保护作用研究

    Institute of Scientific and Technical Information of China (English)

    唐小牛; 汪礼文; 姚勇; 汪学龙

    2012-01-01

    immunized with pcD-NA3. l( + )-SjP14 alone (100 jig/mouse ·time). And mice in the synergistic group were injected with pcDNA3. l( + )-S/P14 (100 jig/mouse · time) plus pcDNA3. l( + )-S^GST (100 fig/mouse · time). Two weeks after the last immunization, the cer-cariae of S. japonicum were infected to mice percutaneously (30+ 1 per mouse). Six weeks later, all mice were sacrificed by cervical dislocation. The adult worms were collected and the worm reduction rate was calculated as an index to evaluate the protective effect of DNA vaccines. Meanwhile, the liver was removed and some of them were digested and counted for the egg reduction rate. HE staining method was used to detect the hepatic changes and granuloma. After immunizing the mice, the results showed that DNA vaccine pcDNA3. l( + )-S)P14 enhanced the immune function of mice infected with cercariae of S. ja-ponicumi and the worm reduction rate and egg reduction rate reached to 44. 6% and 61. 6% , respectively. When combined with DNA vaccine pcDNA3. 1 ( + )-SjGST, the protective effect was significantly strengthened, and both worm and egg burdens were reduced markedly. The worm reduction rate and egg reduction rate reached to 56. 2% and 73. 5%, respectively. The structure of hepatic lobule was integrated togeth-er, and the inflammatory reaction around the egg granulomas was slight. It's suggested that the pcDNA3. l( + )-S/P14 DNA vaccine has some immunoprotection effect on S. japonicum infection, and the protective effect could be enhanced significantly by combining with pcDNA3. l( + )-SjGST DNA vaccine.

  15. Importância epidemiológica de alguns animais silvestres na esquistossomose mansônica Epidemiologic importance of some wild rodents in the schistosomiasis mansoni

    Directory of Open Access Journals (Sweden)

    Urara Kawazoe

    1983-10-01

    ência da contaminação humana, na natureza. Porém, é possível que, futuramente, H. b. leucogaster na presença de B. glabrata, possa servir de reservatório da esquistossomose, na natureza, quando encontrados em abundância e desde que adaptados com cepas adequadas do parasita.The importance of some wild rodents as possible reservoir hosts of S. mansoni related to the epidemiologic chain of this parasite and some biological aspects of these rodents were studied in semi-natural habitats. The experiment was performed in an enclosed area of about 1,000 m² situated in Taubaté, State of S. Paulo, one of the endemic area of human schistosomiasis, during a period of three years and six months (from August 1973 to December 1976. Wild rodents of the following species were used as definitive hosts: Holochilus brasiliensis leucogaster, Zygodontomys lasiurus, Oryzomys nigripes eliurus and Cavia aperea aperea. Biomphalaria tenagophila and B. glabrata were used as intermediate hosts. From August 1973 to January 1976 it was not possible to find any B. tenagophila eliminating S. mansoni cercariae nor any rodents infected with the same parasite. In August, 1975, egg patches of B. glabrata snails were accidentaly introduced into the area and in 1976 some adult snails were eliminating S. mansoni cercariae. In that same year, two Holochilus that were born in the area were discharging S. mansoni eggs in their feces. Some biological data were collected from 41 H. b. leucogaster of which 28 individuals were introduced into and 14 were born in the area. The majority of body weights of rodents born in the area and captured for the first time was between 20 and 50 grams. In this group of 41 rodents observed, body weight continued to increase throughout the life span of each individual sampled. Z. lasiurus and C. a. aperea did not show any infection with S. mansoni and they did not leave any progeny in the area. O. n. eliurus reproduced in the area and remaining there for about 100 days did

  16. Ciclo Vital de Schistosoma mansoni através do Holochilus brasiliensis (Desmarest, 1818 em ambiente semi-natural (Trematoda, Shistosomatidae; Rodentia, Cricetidae

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    Omar dos Santos Carvalho

    1976-10-01

    ções ditas semi-naturais. Os primeiros estudos, entretanto, de Antunes, Milward de Andrade, Katz & Coelho4,,em 1971 e de Antunes5, em 1971 foram feitos utilizando-se o Nectomys s. squamipes.Close to the Pampulha Lake, Belo Horizonte, MG (Brazil, there were collected (july/72 -November/73 28 specimens of Holochilus brasiliensis, 11 of them (39.3% eliminating S. mansoni viable eggs in their faeces. Miracidia from the strain above ("H" could infected Biomphalaria glabrata, the cercariae shed later being also able to infect albino mice, from whose faeces 35,3% of adult worms were recovered in the end of the experiment. S. mansoni cercariae from human strain ("LE" infected 7 H. brasiliensis laboratory specimens, and 30,5% of adult worms could be recovered in the end of 60 days. Anatomopathological studies of H. brasiliensis demonstrated generalized infection, granulomes being detected in the esophagus, stomach, intestines (small and large, tiver, spleen, pancreas and abdominal lymphnodes. Fibrous thickenning of the portal vein intima, granulomes in portal spaces an incipient fibrosis of portal and interlobular spaces were the lesion triggered by the presence of S. mansoni eggs in the liver. In semi-natural surroundings (Fig. 1, the life cycle of S. mansoni could be completed, with no human interference, by using B. glabrata experimentally infected with trematodes from "LE" strain, laboratory-bred H. brasiliensis and B. glabrata specimens from hat seminatural surroundings. It was observed that both strains ("H" and "LE" displayed similar behaviour, no morphological differences having been detected between their eggs and adult worms. Field and laboratory studies demonstrated Holochilus brasiliensis to be a satisfactory intermediate host of S. mansoni. It is than possible that, under certains ecological conditions, the cricetids under study may eventually be integrated in the trematode natural cycle, independently from or parallely the presence of man. It must finally be pointed out

  17. 大麻素受体1与FAK在血吸虫肝纤维化小鼠肝组织中的表达%Expression and significance of cannabinoid receptor 1 and FAK in hepatic tissues of schistosomal hepatic fibrosis mice

    Institute of Scientific and Technical Information of China (English)

    欧阳兵; 彭忠田; 王培

    2014-01-01

    目的:探讨大麻素受体1(CB1)与黏着斑激酶(FAK)在血吸虫肝纤维化小鼠肝组织中的表达。方法将32只昆明小鼠分为正常组(n=10)和模型组(n=22),两组动物均普通喂养,8周后处死取肝组织。模型组小鼠采用腹壁贴附法建立血吸虫肝纤维化小鼠模型。根据纤维化程度将模型组分为Ⅰ级肝纤维化组(n=4)、Ⅱ级肝纤维化组(n=8)和Ⅲ级肝纤维化组(n=10)。HE染色观察病理变化,Masson染色观察肝纤维化程度,免疫组织化学法检测不同纤维化组CB 1的表达,RT-PCR法检测各组CB 1 mRNA及FAK mRNA的表达。结果模型组可见明显虫卵结节及纤维化改变;不同纤维化组均可见CB 1、CB 1 mRNA及FAK mRNA表达,且随着肝脏纤维化程度的增加,CB1、CB1 mRNA及FAK mRNA的表达增加(P<0.05)。结论 CB1和FAK参与了血吸虫肝纤维化的发生与发展。%Objective To investigate the expression and significance of cannabinoid receptor 1 (CB1)and focal adhe-sion kinase (FAK)in hepatic tissues of schistosomal hepatic fibrosis mice.Methods A total of 32 Kunming mice were randomly divided into two groups:normal control group (n=10)and model group (n=22).The schistosome-induced liver fibrosis models were established by attaching cercaria to the skin on the ventral side of the mice and allo-wing infection to occur via direct penetration.All mice were raised normally,and at week 8 all mice were sacrificed to gain hepatic tissue samples.Mice in the model group were divided into 3 subgroups according to the severity of hepatic fibrosis.The pathological changes were determined by HE staining,the degrees of fibrosis were examined by Masson staining,the expression of CB1 was detected by immunohistochemical method,and the expressions of FAK mRNA and CB 1 mRNA were tested by reverse transcription polymerase chain reaction (RT-PCR).Results In the model group, significant schistosome egg

  18. 日本血吸虫SIEA66-68kDa抗原的分离、纯化及免疫保护性研究%Isolation and purification of the 66-68 kDa soluble immature egg antigen Schistosoma japonicum and its protective immunity

    Institute of Scientific and Technical Information of China (English)

    姜孝新; 汪世平; 刘雪琴; 李庆华; 刘明社; 何卓; 彭先楚; 徐绍锐

    2011-01-01

    To investigate the immunoprotection of 66-68 kDa soluble antigen of immature egg of Schistosoma japonicum (SIEA66-68kDa) and to evaluate its feasibility of being used as a molecular vaccine antigen, the SIEA66-68kDa was prepared through SDS-PAGE electrophoresis, protein band resection, electro-elution and ultrafiltration, and the isolated product of protein was used as antigen to immunize Kunming strain of mice. After 3 courses of immunization, mice were challenged with cercariae of S. japonicum, and the reduction rates of worms and eggs were compared with those of the control group with inoculation of PBS. It was found that the mono-specific antibody response against SIEA66-68kDa protein could be induced in mice immunized with this protein. The SIEA66-68kDa could induce significant reduction in adult worms (41.70 %). The rates of egg reduction in the SIEA66-68kDa group reach 51.23%, 59.26% and 45.17% in the liver, intestine tissue and feces, respectively, with significant difference when compared with the control group. It is concluded that the 66-68 kDa immature egg antigen of S. japonicum could protect the Kunming strain of mice from the infection of this parasite, and it could be regarded as the target antigen for the preparation of vaccine against S. japonicum infection.%目的 研究日本血吸虫未成熟虫卵可溶性抗原66-68kDa (SIEA66-68kDa)的动物免疫保护力,并对其作为天然分子疫苗的可行性进行评估.方法 采用电泳切胶、电洗脱、超滤离心等技术,分离纯化SIEA66-68kDa天然分子抗原,免疫小鼠,待其产生抗体后进行尾蚴攻击感染(40尾/只),计算减虫率和减卵率.结果 SIEA66-68kDa天然蛋白质分子能刺激机体产生抗日本血吸虫的作用,其减虫率为41.70%,每克肝脏减卵率为51.23%,雌虫子宫减卵率为29.30%,每克大肠减卵率为59.26%,每克粪便减卵率为45.17%,与对照组相比差异具有统计学意义(P<0.05).结论 SIEA66-68kDa天然分子抗

  19. 日本血吸虫虫卵、童虫和雌雄成虫膜蛋白的双向电泳%Analysis of membrane proteins from egg, schistosomulum, adult male and female worm of Schistosoma japonicum by two dimensional electrophoresis

    Institute of Scientific and Technical Information of China (English)

    程国锋; 冯新港; 林矫矫; 石耀军; 陆柯; 周元聪; 蔡幼民

    2005-01-01

    Membrane proteins were extracted from eggs, schistosomulum, adult male and female worms of Schistosoma japonicum in order to analyze the differently expressed profile by two dimensional electrophoresis. Schistosomulum and adult worms were obtained from rabbits infected with 1 500 cercariaes on 14 and 42 days after challenge, respectively. Adult male and female worms on 42 days were manually detached and stored into liquid nitrogen until use. Eggs were collected by PercollTM from the liver of rabbits. ProteoPrep Membrane Extraction KitTM was employed to extracted membrane proteins by reducing and alkylating with TBP and iodoacetamide from 200mg of eggs, schistosomulums, adult male worm and female worms, respectively. Immobilized pH gradient strips with a linear pH range of 3-10(130mm) were rehydrated together with membrane proteins (30μg) in 250μl solution containing 7mol urea, 2mol thiourea, 2% SB3-10, 4% CHAPS, 40mmol Tris, 30mmol DTT, then separated on 12.5% SDS polyacrylamide gel for the second dimensional electrophoresis. Gels were stained with silver, scanned by Labscan, and analyzed using ImageMasterTM Analysis software. The 2D maps of egg, schistosomulum, adult female worm and male worm were showed 78±3, 67±3, 108±4 and 122±4 spots respectively. There were 35±1 spots which showed specific expression in female worm as compared with male worm, but 45±2 spots were in male worms. Most differently expressed spots between male and female worms were located in the area of 40-70kD and pI 4-7. The large number of unique spots from sehistosomulum was located in the area of alkalescence. The 2D map of for adult male worms uniquely showed 5 spots as compared with that of schistosomulum and female worm. The female worm showed 4 unique spots as compared with that of schistosomulum, egg and male worm. The unique spots between male and female worms were identified by the database of SWISS 2D-PAGE according to the molecular weight and isoelectronic point

  20. Studies on Schistosomiasis japonica and Saponins

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    Edito Garcia

    1980-01-01

    Full Text Available The molluscicidal activity of the bark of Entada phaseoloides and extracts from tubers of its related specie, Entada parvifolia against Oncomelania quadrasi, the snail intermediate host of Shistosoma japonicum in the Philippines were determined.The commercial gogo bark applied to waters with O. quadrasi, in the proportion of 2 gms/liter will kill 100% of snails within 24 hours. At this concentration miracidia and cercariae of S. japonicum in the same waters will die within one hour, thus, making the water safe or noninfective for some time. At the dose 100 gms/sqm of water-covered terrestial snail habitats, provided previously cleared of vegetations, at least 90% of O. quadrasi will die within 24 hours. These measures can be practical on a self-help basis by inhabitants of schistosomiasis endemic areas where gogo plant grows or where its bark is marketed.At dilution of 1:5,000 saponin extracted from tubers of E. parvifolia killed at least 90% of snails after 24 hours exposure while ethanol (crude saponin and other extracts require at least 1:2,000 concentration to kill at least 90% of O. quadrasi. At these concentrations and the expenses and time involved in the preparation of these extracts, they are not economical or practical for large scale use of molluscicides.It is suggested that methods of extraction and purification which require little time of preparation and a cheaper but of higher recovery rate of molluscicidal principles be developed.Surveys of barrios in three towns of Leyte, endemic for Schistosomiasis japonica using the circum oval-precipitin test (COPT and stool examination in the same subjects were undertaken. Findings show that the use of blood COPT method is advantageous over that of the stool examination in schistosomiasis surveys as its prescribed procedure is simple, specific and more sensitive. Moreover, the prevalence rate it determined was higher than that obtained by the stool examination in all three towns studied with

  1. HISTOLOGICAL STUDIES ON THE DEVELOPMENT OF EURYTREMA COELOMATICUM IN THE SNAILS BRADYBAENA SIMILARIS FERUSSAC%腔阔盘吸虫在贝类宿主体中发育的组织学研究

    Institute of Scientific and Technical Information of China (English)

    杨玉荣

    2001-01-01

    internal and external cyst walls, the internal cyst wall surrounded the central area that the germ cells aggregate. After 3 months postinfection, daughter sporocyst present the cercarial embroys. At 118 days postinfection, the cercariae in daughter sporocyst were mature and daughter sporocyst moved to pulmonary cavity.

  2. Infecção natural de roedores silvestres pelo Schistosoma mansoni Natural infection of sylvatic rodents by Schistosoma mansoni

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    Tânia Maria Correa Silva

    1989-06-01

    . Miracidia isolated from the eggs recovered from Nectomys readly infected laboratory-raised Bahia strain of Biophalaria glabrata. Cercariae then obtained infected Swiss mice in a similar way as the human strains of S. mansoni kept in laboratory. Also, Swiss mice left in contact with water collections in Planalto were easily infected, which proved the transmissibility potential of the area. In conclusion: sylvatic rodents in the area of Planalto tolerate well S. mansoni infection, eliminate viable eggs in the stools, are usually infected with a strain probably of human origin and therefore may play a role in maintaining parasite cycle in the area.

  3. Schistosoma japonicum-infected hamsters (Mesocricetus auratus) used as a model in experimental chemotherapy with praziquantel, artemether, and OZ compounds.

    Science.gov (United States)

    Xiao, Shu-hua; Mei, Jing-yan; Jiao, Pei-ying

    2011-02-01

    The purpose of the study is to better understand the antischistosomal properties of artemether, praziquantel, and ozonide (OZ) compounds (synthetic trioxolanes, secondary ozonides) in hamster (Mesocricetus auratus) model. A total of 230 male hamsters infected each with 100 Schistosoma japonicum cercariae were used in the study. Groups of five to ten hamsters were treated orally with artemether, praziquantel, and OZ78 or OZ277 7-35 days post-infection at single doses of 50, 100, 150, or 200 mg/kg. Untreated but infected hamsters in each batch of test served as the control. All treated hamsters were sacrificed 4 weeks post-treatment for collection of residual worms using perfusion technique. Nonparametric method (Mann-Whitney test) was used to analyze the data. In groups of five hamsters treated with artemether 7, 14, 21, 28, and 35 days post-infection at single doses of 150 and 200 mg/kg, the difference of mean worm burden between each treated group and control group was statistically significant (P0.05). Further test with various single doses of 50-200 mg/kg confirmed the similar susceptibility of 7-day-old juvenile and 35-day-old adult schistosomes to artemether. After administration of praziquantel 100 mg/kg to groups of five hamsters 7, 21, and 35 days post-infection, higher worm burden reduction of 95.5% was seen in the group with 35-day-old adult schistosomes while in the groups with 7- and 21-day-old juvenile schistosomes, poor efficacy was seen with mean worm burden reductions of 36.6% and 35.6%. In the same batch of hamster treated with praziquantel 200 mg/kg, the moderate effect of the drug against 7- and 21-day-old worms was seen, but their mean worm burden was significantly higher than that of the group with adult schistosomes. In comparison of artemether and praziquantel against various stages of schistosomes, the results further demonstrated that artemether possessed similar effect against juvenile and adult schistosomes in hamsters, while praziquantel

  4. Patogenesis of pipe-stem fibrosis of the liver (experimental observation on murine Schistosomiasis Patogenia da fibrose "pipe-stem" do fígado (observações experimentais na esquistossomose murina

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    Zilton A. Andrade

    1987-09-01

    Full Text Available Mice infected with 30 cercariae of Schistosoma mansoni developed portal and septal fibrosis due to the massive and concentrated deposition of eggs in the periportal areas which occurred following the 16th week after infection. The lesion resembled pipe-stem fibrosis seen in human hepatosplenic schistosomiasis in the following characters: portal fibrosis interconnecting portal spaces as well as portal spaces and central canals; portal inflammation; periovular granulomas; vascular obstruction and telangiectasia. The liver parenchyma maintained its normal architecture. Vascular injection techniques with Indian ink and vinylite revealed that the portal system developed numerous dilated collateral venules coming from the large and medium-sized portal branches, about 10 weeks after schistosome infection. The lodging of schistosome eggs into these collaterals resulted in granulomatous inflammation and fibrosis along all the portal tracts, thus forming the pipe-stem lesion. Although not readily demonstrable grossly, the pipe-stem fibrosis of murine schistosomiasis has many similarities with the human lesion and can be considered to have the same basic pathogenesis.Camundongos infectados com 30 cercárias do Schistosoma mansoni desenvolveram fibrose porta em virtude de um depósito progressivo e concentrado de ovos na região periportal, o que aconteceu a partir da 16ª semana da infecção. Esta fibrose certas características da chamada fibrose "pipe-stem" do homem vista na forma hepatoesplênica da esquistossomose, tais como obstrução das radiculas porta, telangiectasia, conexão fibrosa entre espaços porta e entre estes e veias centrais, além de certo grau de fibrose septal, presença dos granulomas em várias fases evolutivas e reação inflamatória crônica difusa, enquanto o parênquima hepático mantinha a sua estrutura lobular normal. As técnicas de injeção vascular com tinta da China e com vinilite feitas no sistema porta permitiram a

  5. Avaliação da esquistossomose e de outras parasitoses intestinais, em escolares do município de Bambuí, Minas Gerais, Brasil Evaluation of the schistosomiasis and others intestinal parasitosis in the school children of Bambuí county, Minas Gerais, Brazil

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    Roberto Sena Rocha

    2000-10-01

    children shed eggs of Schistosoma mansoni. The only intermediate host found was Biomphalaria glabrata and none of them was shedding cercariae of S. mansoni. When these data were compared with data from other surveys previously effected in the county, a decline was observed in the prevalence of all parasites. Some hypotheses which may explain this decline are discussed, such as: intense urbanization process and improvement of social-sanitary conditions of the county.

  6. Efficiency of Immunization of Mice with Irradiated Antigen Against Schistosoma mansoni Infection in Comparison with Praziquantel

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    Mona A. El-Gawish, Manar N. Hafez, Fatma A. Eid* Maha G. Soliman*

    2006-12-01

    Full Text Available Introduction: The present study is an attempt to evaluate the protective effect of schistosomula antigen and the current antischistosomal drug praziquantel (PZQ as a reference drug on mice infected with S. mansoni. Material and Methods: Mice were vaccinated by irradiated or non-irradiated schistosomula antigen, both at a dose of 100 ug protein/mice once weekly for 3 weeks, before infection with alive cercariae and compared with the treatment with i.m. injection of praziquantel at a dose of 40 mg/kg b.wt. 4 times once weekly for 4 weeks after infection. The degree of resistance or protection induced by immunization and chemotherapy was assessed 45 days post­infection and evaluated by physiological, parasitological, immunological as well as histological parameters. Results: The results indicated that immunization with -irradiated antigen at 20 Krad or the treatment with PZQ resulted in significant reduction in ova count in liver and intestine tissues more than those vaccinated with non-irradiated antigen compared with infected group. Immunized group with irradiated antigen and the group treated with PZQ showed a significant decrease in liver enzymes activity (ALT, AST and -GT, while in immunized group with non-irradiated antigen, there was a significant increase in AST and -GT as compared to infected group. The level of alkaline phosphatase enzyme was significantly increased in all investigated groups compared to infected one. Treatment with PZQ or immunization with irradiated or non-irradiated schistosomula antigen induced amelioration in serum IL-10 and TNF-. Scanning electron microscope demonstrated normal mature worms in infected group after 45 days from infection. In contrast, many changes were detected in the rest groups as alterations in the tegument, implosion of tubercles which appeared pealed and sloughed off and most of the spines were detached and separated. Histological examination of liver sections of infected mice revealed lobular

  7. Effect of Artemether on the Tegument of Adult Schistosoma haematobium Recovered from Mice%蒿甲醚对感染小鼠体内埃及血吸虫皮层的损害

    Institute of Scientific and Technical Information of China (English)

    肖树华; Marcel TANNER; 沈炳贵; Jürg UTZINGER; Jacques CHOLLET

    2006-01-01

    Objective To assess the effect of artemether on the tegument of adult Schistosoma haematobium harbored in mice. Methods Ten mice were infected subcutaneously with 100-120 S. haematobium cercariae each. At day 81 post-infection, 8 mice were treated orally with 400 mg/kg artemether. Mice were sacrificed at 1, 3, 7 and 14 days post-treatment, and schistosomes were collected by the perfusion technique, fixed and examined under a scanning electron microscope. Schistosomes obtained from the 2 untreated mice served as a control. Results Twenty-four hours post-treatment, tubercles on the tegument of male worms showed lesions, characterized by enlargement, collapse and partial peeling off from the border with the tegument. In both male and female worms, the tegument showed focal or extensive swelling, fusion, vacuolization, erosion, peeling, and destruction of sensory structures. Three days post-treatment,tegumental alterations further aggravated; particularly severe damage was the swelling or collapse of the oral sucker observed in both sexes. In addition, extensive swelling, erosion and peeling of tegumental ridges and destruction of discoidlike sensory structures were seen in female worms. Seven to 14 days post-treatment, moderate-to-severe damage was still evident in some worms, whereas other worms surviving the treatment showed apparent recovery in most parts of their tegument. Conclusion Artemether causes extensive and severe tegumental damage in adult S. haematobium.%目的 评价蒿甲醚对小鼠体内埃及血吸虫皮层的损害作用.方法 8只小鼠于感染埃及血吸虫尾蚴后81 d,用单剂蒿甲醚400 mg/kg口服治疗.治疗后1、3、7和14 d各剖杀2只小鼠,用灌注法收集血吸虫,并按常规方法固定和处置虫体,作扫描电镜观察.从另2只未作治疗的感染小鼠取虫作对照.结果 用蒿甲醚治疗后24 h,雄虫的皮层结节肿大、破溃或从皮层上剥落;在雄虫和雌虫的体表可查见有局灶性或广泛的

  8. Effects of dihydroartemisinin, artemether, and artesunate administered orally in multiple doses or in combination to treat mice with schistosomiasis%双氢青蒿素、青蒿琥酯和蒿甲醚连续给药及伍用治疗小鼠血吸虫 效果观察

    Institute of Scientific and Technical Information of China (English)

    李洪军; 汪伟; 曲国立; 戴建荣; 陶永辉; 李幼子; 邢云天; 魏剑英; 梁幼生

    2011-01-01

    Objective To investigate the effects of dihydroartemisinin, artesunate, and artemether administered orally in multiple doses or in combination to treat mice with schistosomiasis in'order to provide an experimental basis for treatment of the causes of schistosomiasis japonica. Methods Mice were infected with 40±l Schistosoma ja ponicum cercariae via the abdomen and treated with dihydroartemisinin, artesunate, and artemether at multiple doses or in combination (all doses were 300 mg/kg) on days 6 - 8 or 34 - 36 post-infection. Mice were sacrificed on day 50 post-infection, the adult worms were recovered, and the total and female worm reduction rates were calculated. Results Administration of dihydroartemisinin, artesunate, or artemether for 3 successive days reduced the total worm burden by 79. 5% -86. 0% and the female worm burden by 79. 4% -86. 7% depending on the treatment protocol followed on days 6 - 8 post-infection, though differences in the total and female worm burden were not statistically significant (all P values < 0. 05). When the same treatment was given on days 34 - 36 post-infection, the total worm burden decreased 73. 8% - 75. 8% and the female worm burden decreased 88. 7% - 93. 1%, though differences in the total and female worm burden were not statistically significant (all P values < 0. 05). Conclusion Administration of dihydroartemisinin, artesunate, and artemether in multiple doses or in combination affected both juvenile and adult S. japonicum, but there was no obvious difference in the effectiveness of the two forms of administration.%目的 观察双氢青蒿素、青蒿琥酯和蒿甲醚连续给药或伍用治疗小鼠血吸虫病的效果,为日本血吸虫病病原学治疗提供药物配伍实验依据.方法 采用腹部贴片感染法,每鼠感染日本血吸虫尾蚴40±1条,分别于感染后6~8 d(童虫期)和34~36 d(成虫期),以300 mg/kg双氢青蒿素、青蒿琥酯和蒿甲醚连续给药及3种药物等

  9. Hepatic regeneration after partial hepatectomy in mice infected with Schistosoma mansoni, at the acute and chronic phases of the disease Regeneração hepática após hepatectomia parcial em camundongos infectados com Schistosoma mansoni, nas fases aguda e crônica da doença

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    G. COSTA

    1999-07-01

    Full Text Available Outbred male albino mice normal or infected with 30 cercariae of Schistosoma mansoni (LE strain were submitted to 65% hepatectomy during the acute (70 days and chronic phase (160 days phases of the disease. A group of the infected animals was treated with 400 mg/kg of oxamniquine during the acute phase before hepatectomy. Non-infected, infected and treated but not hepatectomized animals were kept as controls. Hepatic regeneration was evaluated by incorporation of tritiated thymidine, intraperitoneally injected into non-hepatectomized and hepatectomized animals, 24 hours after surgery. The results showed that removal of 65% of the hepatic parenchyma, during the acute phase, led to a statistically significant increase of thymidine incorporation, when compared with the uninfected hepatectomized controls. This phenomenon was not observed at the chronic phase. Treatment with oxamniquine administered during the acute phase led to a decrease in thymidine incorporation rate 160 days after infection (90 days after treatment and 24 hours after hepatectomy. The data suggest that infection with S. mansoni represents a considerable stimulus for the regenerative capacity of the liver during the acute, but not the chronic phase of disease.Camundongos albinos não-isogênicos, normais ou infectados com 30 cercárias de Schistosoma mansoni (cepa LE foram submetidos a hepatectomia parcial (65% na fase aguda (70 dias ou crônica (160 dias da doença. Um grupo de animais infectados foi tratado, na fase aguda, com 400 mg/kg oxamniquine antes da hepatectomia. Animais não infectados, infectados e tratados mas não hepatectomizados, foram mantidos como controles. A regeneração hepática foi avaliada pela incorporação de timidina tritiada, injetada peritonealmente em animais hepatectomizados ou não, 24 horas após cirurgia. Os resultados mostraram que a remoção de 65% do parênquina hepático, na fase aguda, levou a um aumento estatisticamente significativo da

  10. Decay of antibody isotypes against early developmental stages of Schistosoma mansoni after treatment of schistosomiasis patients

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    Herminia Yohko KANAMURA

    1997-09-01

    Full Text Available Antibodies to a number of parasite antigens are found in schistosomiasis patients, and antibodies to early developmental stages were demonstrated to be efficient immunologic markers for the diagnosis of schistosomiasis. In the present study, decay patterns of IgM and IgG antibodies against cercariae and schistosomula were investigated, in comparison to antibodies against worms and eggs in schistosomiasis patients after chemotherapy, for an investigation of seroepidemiologic aspects. Data obtained in the study of 359 serum samples from patients with Schistosoma mansoni infection, noninfected individuals, and patients followed-up for a period of 12 to 15 months after treatment provided the basis to postulate a general pattern for the kinetics of antibody decay. Before treatment, the antibody pattern was represented by a unimodal curve, which shifted to a bimodal curve after treatment, and ended with a unimodal curve similar to that for the noninfected group. Different types of antibodies were classified into four categories according to their decay features, and anti-schistosomulum IgM was classified into the moderate-decay caterogy, whereas other antibodies to early parasite stages were classified into the slow-decay category. The present methodology permits the identification of the most suitable antibodies to be detected in field control programs for schistosomiasis or other parasitosesEm pacientes com esquistossomose, são encontrados anticorpos contra grande número de antígenos parasitários, e aqueles contra formas evolutivas jovens do parasita demonstraram que eram eficientes marcadores imunológicos para o diagnóstico da esquistossomose. Padrões de queda de anticorpos IgM e IgG contra cercária e esquistossômulo foram aqui estudados, comparativamente aos dos anticorpos contra verme e ovo, em pacientes esquistossomóticos após quimioterapia, abordando aspectos soroepidemiológicos. Dados obtidos no estudo de 359 amostras de soros

  11. Effects of Schistosoma japonicum infection on the expression of Arg-1 and Fizz-1 proteins in liver tis-sues of mice with high-fat diet induced obesity%日本血吸虫感染对高脂饮食小鼠肝组织Arg-1和 Fizz-1表达的影响

    Institute of Scientific and Technical Information of China (English)

    孙科; 赵娜; 王维; 李素梅

    2014-01-01

    effects on mice with diet induced obesity were induced dur-ing acute infection of Schistosoma japonicum cercariae(6 weeks). The chronic infection of Schistosoma ja-ponicum cercariae(12 weeks)might be helpful in reversing hepatic insulin resistance in mice with diet in-duced obesity by changing the polarity of macrophages in liver tissues.%目的:探讨日本血吸虫感染对高脂饮食小鼠巨噬细胞选择性活化和肥胖小鼠肝脏胰岛素抵抗的影响及可能机制。方法36只雄性 C57BL/6J 小鼠,随机分为正常对照组(normal control group,NC 组;n=12)、高脂饮食组(high-fat diet group,HF 组;n=12)及高脂饮食复合日本血吸虫感染组(high-fat diet with Schistosoma japonicum infection group,HSj 组;n=12)。分别在高脂饲养第6周末及12周末时检测空腹血糖(fasting peripheral blood glucose,FBG)、空腹血浆胰岛素(fasting plasma insulin,FINS)水平,并计算胰岛素抵抗指数(insulin resistance index,HOMA-IR);逆转录-聚合酶链反应(RT-RCR)和免疫组化分别检测肝脏组织 IL-6及选择活化型巨噬细胞的特异性标志物精氨酸酶-1(arginase-1,Arg-1)、发现于炎症区域(found in inflammatory zone-1,Fizz-1)mRNA 和蛋白表达情况。结果感染第6周末及12周末,HF 组 HOMA-IR 均高于 NC 组和 HSj 组(P﹤0.05);HF 组感染12周末的 HOMA-IR 比感染6周末高(P>0.05)。感染6周末 HF 组和 HSj 组 IL-6表达明显高于 NC 组(P﹤0.05),12周末 HF 组 IL-6表达明显高于 HSj 组和 NC 组(P﹤0.05)。感染第6周末及12周末,HF 组Arg-1、Fizz-1表达均低于 NC 组(P﹤0.05);感染第12周末 HSj 组 Arg-1表达最高,HF 组 Arg-1表达最少;感染第6周末及12周末,HSj 组 Fizz-1表达均高于 HF 组和 NC 组(P﹤0.05)。结论血吸虫尾蚴急性感染(6周)小鼠可能会发挥促炎作用,慢性感染(12周)可能是通过改变肝组织

  12. Colonização de Pomacea haustrum (Reeve, 1856 em localidade com esquistossomose mansoni: Baldim, MG (Brasil. (Prosobranchia, Pilidae Colonization of Pomacea haustrum (Reeve, 1856 at localility with Schistosomiasis mansoni: Baldim, MG (Brazil

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    Roberto Milward-de-Andrade

    1979-06-01

    introduced into 5 brooks and 2 ditches where Biomphalaria glabrata (primarily and B. straminea (secondarily predominated. From 1968 to 1971, the infection rate of B. glabrata by S. mansoni ranged from 2.1% to 11.9%. None of the B. straminea specimens collected, however, were seen to be liberating cercariae of this trematode. After the introduction of Pilidae, only once were two positive B. glabrata specimens (1.8% detected. A decrease in the planorbide population was observed, as well as an increase in the pomacea density to 20.0 and 121.6 specimens per square meter in the brooks and ditches, respectively. P. haustrum density was estimated by the "quadrat" method. Of the planorbides in the experiment, 65.2% (1,526 were collected from July/68 to July/72 and the rest were obtained after the introduction of the predator-competitor species, as follows: 15.0% (352 in 1976; 16.1% (377 in 1977; and 3.7% (87 in 1978. Although transferred from a lenitic medium (Sete Lagoas, MG, the pomaceae became perfectly adapted to the lotic collections of Baldim, and proved to be capable of replacing the original B. glabrata populations of several biotopes or, at least, of becoming predominant, with no damage to the new ecosystems. Based on the data presented above and the knowledge previously acquired in the study of the biology and ecology of the species, it is believed that, under similar conditions, Pomacea haustrum (Reeve, 1856 - and, by extension, P. lineata (Spix, 1827 and P. canaliculata (Lamarck, 1822, as well as other species from the same genus - may be successfully used in the biological control of the intermediate hosts of S. mansoni.

  13. Studies on the effect and mechanism of CD4+ CD25+ regulatory T calls in Schistosoma japonicum immune evasion%CD4+CD25+调节性T细胞在血吸虫免疫逃避中的作用及机制研究

    Institute of Scientific and Technical Information of China (English)

    唐春莲; 郭思洁; 杨进; 祝青; 刘晓宏

    2014-01-01

    目的 探讨CD4+ CD25+调节性T细胞(Tregs)在日本血吸虫免疫逃避中的作用及其机制.方法 雌性BALB/c小鼠随机分成3组,即正常对照组、感染对照组和抗CD25单克隆抗体(anti-CD25 mAb)组,各感染组每只小鼠均经腹部皮肤感染日本血吸虫尾蚴40条,感染后两周anti-CD25 mAb组每只小鼠经腹腔注射anti-CD25 mAb 300 μg,其它组注射等体积的PBS,感染后5周杀鼠冲虫,计数每只小鼠虫荷.收集脾细胞及培养上清,流式细胞术检测脾淋巴细胞中CD4+ CD25+ Tregs百分比.双抗夹心ELISA法测定脾细胞培养上清中的γ-干扰素(IFN-γ)、IL-4、IL-5、IL-10的含量.结果 Anti-CD25mAb组虫荷(23.17 ±6.94)明显低于感染对照组[(30.17 ±5.85),P=0.047];感染对照组脾淋巴细胞中CD4+ CD25+ Tregs百分比(2.68 ±0.12)%明显高于正常对照组[(1.98±0.33%),P=0.049],而anti-CD25mAb组脾淋巴细胞中CD4+ CD25+ Tregs百分比(1.28±0.30)%明显低于感染对照组(P=0.000);anti-CD25mAb组脾细胞培养上清中IFN-γ的含量(386.87±24.85) pg/mL明显高于感染对照组[(61.32±8.75) pg/mL,P=0.000],其余细胞因子组间无统计学意义.结论 anti-CD25 mAb能部分封闭CD4+ CD25+ Tregs后有利于机体清除日本血吸虫,其机制可能为增强Th1型免疫反应,宿主CD4+ CD25+ Tregs有助于日本血吸虫逃避宿主的免疫攻击.%Objective To explore the effect and mechanism of CD4 + CD25 + Tregs in S.japonicum immune evasion.Methods Female BALB/c mice were randomly divided into normal control group,infected control and anti-CD25 mAb group.Each mouse was infected percutaneously with 40 S.japonicum cercaria.After 2 weeks infection,anti-CD25 mAb group was injected intraperitoneal with 300 μg anti-CD25 mAb each mouse.After 5 weeks infection,all mice were succumbed to measure worm burden.The percent of CD4+ CD25 + Tregs in spleen was measured with flow cytometer.The expression of gamma interferon (IFN-γ),interleukin-4 (IL-4),interleukin-5

  14. Cloning and Expression of Metalloprotease Gene from Schistosoma japoncum and its Immunoprotective Efficiency%日本血吸虫金属蛋白酶基因的克隆和表达及其对小鼠的免疫保护性研究

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    徐斌; 鞠川; 卢艳; 莫筱谨; 冯正; 许学年; 胡薇

    2011-01-01

    Objective To clone and express a metalloprotease gene of Schistosoma japonicum, purify the expressed protein, and investigate the induced immune response in mice and its localization in the parasite. Methods Specific primers were designed according to the EST sequence and used for amplification of the encoding sequence from the S.japonicum cDNA clone containing S.japonicum metalloprotease. The gene was subcloned into pET-28a plasmid and expressed, and the recombinant protein was purified with HisoTag affinity chromatography. Western blotting was used to analyze the immunogenicity. Eighteen C57BC/6 mice were divided into two groups. Mice in group A were immunized each with 25 μg purified recombinant SjB04 at every 2 weeks for 3 times. Mice in group B received only adjuvant as control. Each mouse was challenged by (40±2) cercariae at the third week after the last immunization. Fecal samples were collected for 6 days from 37th days after challenge. Eggs per gram feces and rate of egg reduction were calculated. S.japonicum adult worms were collected from infected mice, and used for preparing frozen sections and indirect immunofluorescence staining with specific polyclone antibody to S. japonicum metalloprotease. Results The metalloprotease gene SjB04 was cloned, sequenced and expressed. The immuno-fluorescence localization showed that SjB04 protein distributed mainly in the intestinal epithelium of the adult worm. The recombinant protein was specifically recognized by the S. japonicum-infected rabbit sera, showing that the expressed product possessed antigenicity. Mice immunized with the recombinant protein revealed a reduction in numher of adult worms, eggs in feces by 27.1% and 57.8%,respectively. Conclusion The recombinant protein of' S.japonicum metalloprotease has been obtained with Mr 36500.The protein locates in the intestinal epithelium of adult worm. Immunization with the SjB04 protein induces significant reduction of fecal eggs.%目的 克隆和表达

  15. 广东省部分地区卫氏并殖吸虫分布与DNA序列分析%Geographic distribution and gene sequencing of Paragonimus westermani in some areas of Guangdong Province

    Institute of Scientific and Technical Information of China (English)

    陆予云; 刘巧; 唐高兴; 沈浩贤; 钟建新; 谢权超; 傅广华; 陈玉莲; 李豪彬

    2013-01-01

    dissected to detect adult worms of P.westermani.The COI and ITS2 gene sequences of those adult worms were compared with those of known Paragonimus specimen deposited in the GenBank.Results All of the first intermediate hosts in five survey sites of Liangkou,Nankun,Mountain,Dadong,Muxi,Guowu,were identified as Semisulcospira libertina,whose cercariae infection rates were 0.33%,0.15%,0.058%,0.10%,and 0.05%,respectively; the second intermediate hosts in above five sites were all identified as Sinopotamon denticulatum,whose metacercariae infection rates were 100%,100%,38.09%,55.36%,and 65.26%,respectively.The numbers of metacercariae in the five sites were 79.4,105.66,9.16,16.18,and 15.6 per positive crab,respectively,and 11.12,7.87,0.58,0.69,and 0.85 per gram of crab,respectively.All the metacercariae were identical to those of P.westermani.Adult worms and eggs of P.westermani were found in both reservoir hosts of domestic cats and dogs infected artificially.By comparing the COI genes of five representative samples from each survey site with that of Paragonimus #AF219379.21,AF540958.1 from GenBank,we found out the homology to be 99%,99%,99%,98%,and 99%,respectively.In addition,a comparison of the ITS2 gene sequences between the above five samples and Paragonimus #DQ836243.1,DQ351845.1,AB354217.1 from GenBank revealed 98%,99%,98%,98%,and 98% gene homology,respectively.Conclusion Two ultra-high and three high endemic areas of P.westermani are discovered in Guangdong Province.No obvious differences were found among the types of P.westermani in the above five endemic areas.

  16. Seasonal dynamics of the cercarial and metacercarial stages of the microphallid trematode Maritrema eroliae(Digenea: Microphallidae)%滨鹬马蹄吸虫(复殖目:微茎科)的尾蚴和囊蚴期的季节动态

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    M. A. AL-KANDARI; J. M. ABDUL-SALAM; M. A. MOUSSA; B. S. SREELATHA

    2007-01-01

    emergence(i.e., indicating mature infection)in snails. Cercarial emergence from snails was significantly seasonal, a minimum temperature of 20℃ in the Bay must be exceeded to activate emergence. Overall prevalence of infections decreased in larger(older)snails, suggesting parasite interference with host survival and consequently with host population structure. There was a significant correlation between metacercarial abundance and crab size; larger crabs harbored more metacercariae suggesting host tolerance to parasite accumulation. No correlations were detected between metacercarial prevalence and crab size or sex. The presence of mature parasites throughout the year in crabs of both sexes and all size classes, demonstrated by in vitro metacercarial excystment and liberation of ovigerous flukes, suggests continuous transmission from crab to bird is possible. In general, the transmission dynamics of M.eroliae in the Bay are coordinated between the two invertebrate host species and appears to be controlled by a set of temperature-dependent activities influencing the availability of susceptible host populations and infective larval stages, cercariae and metacercariae[Acta Zoologica Sinica 53(3):463-469,2007].

  17. 表达mIFN-γ的重组链球菌的构建及其对重组Sj-F1链球菌疫苗免疫调节作用研究%Construction of recombinant streptococcus expressing mIFN-γ and immunoregulation on recombinant Sj-F1 streptococcus

    Institute of Scientific and Technical Information of China (English)

    彭丹; 杨明; 刘玮; 陈利玉

    2013-01-01

    mice were challenged with S.japonicum cercariae.The immunoprotection was assessed by worm and egg reduction percentage.[Results] The recombinant mIFN-γ Streptococcus was successfully constructed.Immunization experiment showed co-immunization with recombinant mIFN-γ Streptococcus and recombinant Sj-F1 Streptococcus provided 31.56% worm reduction rates and 47.48% egg reduction rates in mice.Compared with that of mice administrated with only recombinant Sj-F1 Streptococcus,the worm and egg reduction rates in co-immunized mice were increased.[Conclusion] The recombinant mIFN-γ Streptococccus can express mIFN-γ.The recombinant mIFN-γ Streptococcus can significantly enhance the protective immunity against S.japonicum infection induced by recombinant Sj-F1 Streptococcus vaccine.

  18. 江苏省血吸虫病监测预警系统的研究Ⅴ长江水域血吸虫毛蚴感染性的监测%Surveillance and forecast system of schistosomiasis in Jiangsu Province V Monitoring of infectivity of Schistosoma japonicum miracidia of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    戴建荣; 洪青标; 梁幼生; 李洪军; 孙乐平; 邢云天; 汪伟; 李幼子; 高扬; 张联恒; 高原

    2011-01-01

    Jiangsu section of the Yangtze River, 500 snails were placed into each site from May to September, once every month. Twenty-eight hours later, all the snails were transferred and raised in an incubator at 25 °C. Two months after the first recovery, the snail infection was detected each month by using the cer-caria-shedding test. Three months after the final placement, all the snails were dissected for observation of the infection. The activities of humans and domestic animals were surveyed in the settings where infected snails were found. The database of surveillance results of sentinel snails in the Yangtze River, Jiangsu Province was established, and the geographical distribution map of site with infected snails was drawn, and the probability that snails were infected with S. Japonicum was estimated. Results A total of 44 717 sentinel snails were placed in 45 sites during the period of 5 months, and 43 477 recovered, with a recovery rate of 97. 23%. A total of 81 410 snails were detected by the cercaria-shedding test, no infections were found. A total of 13 033 snails were dissected, and 5 were infected, with an infection rate of 0. 038%. The probability of snail infection in water was 4. 11 out of a million. Five sites with infected snails were found in 45 sites, with an occurrence rate of 11. 11%. The sites with infected sentinel snails were distributed in south bank (3, 21.43%), north bank (1, 5.56%) and river center (1, 7.69%), respectively.The occurrence rate of sites with infected snails in south bank was 3. 8 times more than that in north bank. Among the 5 sites, 3 were anchor points of boat fishermen. Conclusions The contamination of S. Japonicum eggs in south bank of the Yangtze River is higher than that in north bank in Jiangsu Province, and the anchor point of boat fisherman is one of the important contamination regions. The floating bottle-nylon bag sentinel snails testing method is an effective approach to monitor the contamination of S. Japonicum eggs in

  19. Morbidade da esquistossomose mansoni no Brasil: II - Estudo em quatro áreas de campo nos Estados de Minas Gerais, Sergipe e Paraíba Morbidity of schistosomiasis mansoni in Brazil: II - Study in 4 field areas in the states of Minas Gerais, Sergipe and Paraiba

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    J. Rodrigues Coura

    1983-03-01

    , and Padre Paraíso, both in Minas Gerais State and two others in the Northeast Region (Riachuelo, Sergipe State and Alhandra, Paraíba State. The total sample studied in the four areas was 4,870, divided as follows: Capitão Andrade (area1 - 1,369; Riachuelo (area 2 - 850; Padre Paraíso (area 3 - 1,736; and Alhandra (area 4 - 915. In area 1, with a total population of 1,480 inhabitants, a study of the entire population was attempted. In areas 2, 3, and 4, due to the large number of inhabitants, a systematic sample by conglomerates was studied, of approximately 25 per cent of the population (family grouping of one in every four residences. The study consisted of an evaluation of the economic and sanitary conditions of the population, of contact with the local foci of transmission of schistosomiasis, of the frequency and intensity of infection by S. mansoni and of the relation between parasite load and the different clinical forms of the disease in different age groups. In parallel, a study was carried out of the intermediate hosts in each area and of the frequency of infection with S. mansoni cercariae. The prevalence of active S. mansoni infection was 60.8, 50.5, 63.1 and 46.6 per cent in areas 1, 2, 3 and, with a median egg elimination of 207, 77.6, 391 and 211 per gram, respectively. Progressive increases in frquency of infection of parasite load and of serious forms of the disease were observed from the first to the third decade in the areas of the Southeast Region and a later increase in the same parameters in the Northeast Region. Other correlations between clinical forms of the disease and age groups, sex, and ethnical origins of the patients, as well as frequency among the planorbids, were carried out.

  20. Bioquímica da esquistossomose mansônica: V - atividade mitocondrial em fígados e rins de sagüis (Callitrix penicillata infestados pelo Schistosoma mansoni Biochemistry of mansonic schistosomiasis: V - mitochondrial activity in livers and kidneys of marmosets (Callitrix penicillata infected with Schistosoma mansoni

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    Luiz Erlon A. Rodrigues

    1983-04-01

    , tipo necrose.Mitochondria isolated from livers and kidneys of marmosets (Callitrix penicillata wich were infected with 200 cercariae were studied, not less than 80 but not more than 100 days after infection, with regard to their endogenous respiratory activities. Sodium succinate and alpha keto glutarate were used as substrates. Each experiment was compared with a control specimen, using isolated mitochondria of livers and kidneys from non infected animals. The measurement of the respiratory activity was made polarographically and expressed in microliters of oxygen consumed per milligram of total protein per minute. The results showed that the endogenous respiration of mitochondria isolated from infected animals was always greater than those observed in the control specimens. A stimulus of 217% to the liver and of 84% to the kidney were observed. The sodium succinate activated the respiration of the control livers approximately 85% and provoked an inhibition of 39% in the infected marmoset. Concerning the kidneys this same substrate stimulated both, about 84% and 94% respectively. The alpha keto glutarate stimulated the hepatic mitochondrial respiration approximately 48% and the renal respiration about 84%. In reference to the schistosomotic animals, the alpha keto glutarate did not modify the mitochondrial respiratory capacity of the kidney but did inhibit that of the liver by 58%. The data obtained from our experimental conditions suggest that the liver suffers, much more, in biochemical terms, from mansonic schistosomiasis, than do the kidneys. The activities of the succinate dehydrogenase system and of the alpha keto glutarate complex, permitted the biochemical identification of the different degrees of cellular lesions, mainly in the liver, in our schistosomotic marmosets. These lesions varied from the simplest ones, caused by physical-chemical modifications of the membrane systems, to the most serious ones, such as necrosis.

  1. Estudo seccional sobre esquistossomose mansônica no Município de Riachuelo, Estado de Sergipe

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    Antonio Paulo de Menezes

    1980-12-01

    da esquistossomose mansônica, estando 12 naturalmente infectados. A única espécie encontrada foi a B. glabrata.A sectional dinic and epidemiological study was performed aiming to define the morbidity of the S. mansoni infection in the human population of Riachuelo, Sergipe, in Northeastern of Brazil. Eight hundred and fifty persons from the above community (25% were random-selected and studied: 835 of them had a stool examination done by Lutz sedimentation (Hoffman, Pons and Janer technique and S. mansoni egg counting by Katos' method. A skin test with antigen from adult worm was performed in 393 persons from the sample. The average prevalence of the S. mansoni infections in the population (viable eggs in the stool was 50.54%. The prevalence of the infection by S. mansoni in children under 5 years was considerable lower (6.15% than in the groups from 6-10 (41.5% and in those from 11 to 50 years (average of 75% of infection. The skin test positivity was marked higher than the stool examination in ali ihese groups, but there was a good correaltion between these two methods in ali groups. However in the groups over 50 years there was a drop to 48.3% in the stool positivity for S. mansoni eggs but the skin test remained with a very high positivity (94.11%. There was no difference of positivity either in the stools or in the skin test in relation to the sex but regarding to the race there was a higher prevalence of the infection in blacks and ",mestiços" than in whites. Clinically 73.17% of the infected people were classified in group I (intestinal infection, 24.39% in group II (hepato-intestinal and only 2.43% in the group III (hepatosplenic form. Biomphalaria glabrata was the single vector found in five focci surrounding the community. The infection rate by cercarias of S. mansoni in 1.208 snails colected was ofabout 1% (12 snails positives.

  2. A potential vector of Schistosoma mansoni in Uruguay Um vetor potencial do Schistosoma mansoni no Uruguai

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    W. Lobato Paraense

    1989-09-01

    Full Text Available Susceptibily experiments were carried out with a Biomphalaria straminea-like planorbid snail (Biomphalaria aff. straminea, species inquirenda from Espinillar, near Salto (Uruguay, in the area of the Salto Grande reservoir, exposed individually to 5 miracidia of Schistosoma mansoni (SJ2 and BH2 strains. Of 130 snails exposed to the SJ2 strain, originally infective to Biomphalaria tenagophila, 30 became infected (23%. The prepatent (precercaria period ranged from 35 to 65 days. The cercarial output was irregular, following no definite pattern, varying from 138 to 76,075 per snail (daily average 4.3 to 447.5 and ending up with death. Three specimens that died, without having shed cercarie, on days 69 (2 and 80 after exposure to miracidia, had developing secondary sporocysts in their tissues, justifying the prospect of a longer precercarial period in these cases. In a control group of 120 B. teangophila, exposed to the SJ2 strain, 40 became infected, showing an infection rate (33.3% not significantly different from that of the Espinillar snail (X [raised to the power of] 2 = 3.26. No cercarie were produced by any of the Espinilar snails exposed to miracidia of the BH2 strain, originally infective to Biomphalaria glabrata. Four specimens showed each a primary sporocyst in one tentacle, which disappeared between 15 and 25 days post-exposure, and two others died with immature, very slender sporocysts in their tissues on days 36 and 54. In a control group of 100 B. glabrata exposed to BH2 miracidia, 94 shed cercariae (94% and 6 remained negative. Calculation of Frandsen's (1979a, b TCP/100 index shows that "Espinillar Biomphalaria-SJ2 S. mansoni" is a vector-parasite "compatible" combination. Seeing that tenagophila-borne schistosomiasis is prevalent in Rio de Janeiro and São Paulo states and has recently spread sothwards to Santa Catarina state, and the range of B. tenagophila overlaps taht of the Espinillar Biomphalaria, the possibility of

  3. 血吸虫病肝纤维化小鼠中肝星状细胞迁移功能改变的实验研究%Alterations of hepatic stellate cells on movement abilities in mice infected with Schistosoma ;japonicum

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    李兰; 王亚琦; 王洪武; 孙颖; 黄加权; 范翔雪; 宁琴

    2014-01-01

    目的:探讨影响日本血吸虫病肝纤维化小鼠肝组织中肝星状细胞(HSCs)迁移运动功能变化的相关因素。方法 SPF级6~8周龄Balb/c小鼠16只,随机分为模型组(8只)和对照组(8只),以血吸虫尾蚴腹部贴附法建立感染模型,正常组予以生理盐水代替。于感染后8周末处理小鼠,取部分肝组织石蜡包埋,进行病理学评估,免疫荧光染色检测HSCs(α-SMA,红光)运动蛋白Fascin(绿光)的表达;另取部分肝组织,采用Real-time PCR方法检测迁移诱导因子转化生长因子β1(TGF-β1)、血小板源性生长因子(PDGF)以及单核细胞趋化因子1(MCP-1)的表达以及HSCs运动蛋白α-SMA、Fascin的表达。结果8周末时,模型组小鼠肝组织中已形成明显肝纤维化。模型组小鼠肝组织中TGF-β1、PDGF 以及MCP-1的基因表达水平分别是对照组的30倍、14倍及14倍,差异具有统计学意义(P=0.033、P=0.039以及P=0.037);同时,模型组中HSCs运动相关蛋白α-SMA和Fascin的基因表达水平分别是对照组的9倍和5倍,差异具有统计学意义(P=0.004、P=0.018);荧光共聚焦结果提示,模型组小鼠肝组织中α-SMA(红色)和Fascin(绿色)表达部位一致,集中在虫卵周围肝纤维化区域,较对照组二者表达明显增加,且红绿光分布多重叠。结论诱导HSCs运动迁移的因子表达增加和HSCs自身的运动相关蛋白表达增加均有利于HSCs运动迁移能力增强。%Objective To analyze the relevant changes of hepatic stellate cells (HSCs) migration in mice with Schistosoma japonicum infection. Methods A total of 16 SPF balb/c mice aged 6-8 weeks, were randomly divided into two groups, namely, control group (n=8) and infected group (n=8). The mice from the infected group were suffered from skin infection by schistosome cercariae, while the mice in control group were given an equal volume of saline

  4. 日本血吸虫感染不同相容性动物宿主的比较研究%Comparative study on Schistosoma japonicum infection in different permissive animal hosts

    Institute of Scientific and Technical Information of China (English)

    杨健美; 林矫矫; 苑纯秀; 冯新港; 傅志强; 石耀军; 刘金明; 洪炀; 李浩; 陆珂

    2012-01-01

    The aim was to understand the difference for worm development , worm morphology and host's histopatholo-gy in Schistosoma j aponicum (S. j aponicum) infected animal hosts , including natural hosts and experimental animal hosts . We artificially infected six animal hosts (yellow cattle , water buffalo , goat, New Zealand rabbit , BALB/c mice , and Wistar rat) with the same source of S . japonicum cercariae . The parasites were perfused through the hepatic portal vein on day 49 after infection. The male and female worms were detached manually and counted , and the length and width of the worms were measured . The results showed that the worm recoveries in permissive hosts were higher than that in non permissive hosts , and the length of the worms from permissive hosts were greater than those from non permissive hosts . Parasites in all the hosts could develop into maturation and cause liver damage in their hosts except for Wistar rat . The livers from permissive hosts were fulfilled with white egg nodules , and composed of egg- granulomas ; while the livers from water buffalo were red but with few egg nodules ; the livers from Wistar rat had no damage at all . The histologies! sections from livers of infected natural hosts showed that in yellow cattle and goat , hepatocytes displayed mild swelling , and a large number of inflammatory cells were seen to be in -filtrating and aggregating , including eosinophils and lymphocytes , and typical striped eosinophilic deposits were observed . Compared with yellow cattle and goat , the structural integrity of the hepatic lobules in infected buffalo was intacted in the liv -ers . There was actinomorphous distribution of hepatic cord centered on central veins , polygonal hepatocytes without edema and inflammatory cell infiltration , leaving only scattered neutrophils and monocytes . This study provides reference data for labora- tory and field studies in understanding the differences of S. j aponicum infection in different

  5. Protective effect of SjC23-Hsp70 DNA vaccine and interleukin-12 on Schistosoma japonicum infection in water buffalos%日本血吸虫SjC23-Hsp70 DNA疫苗与IL-12对水牛保护性作用的研究

    Institute of Scientific and Technical Information of China (English)

    胡平成; 夏大; 崔虹艳; 张苹芳; 何永康; 喻鑫玲; 孙振球

    2012-01-01

    目的:研究日本血吸虫中国大陆株23 kD膜蛋白-热休克蛋白(SjC23-Hsp70)DNA疫苗联合佐剂白细胞介素12(IL-12)质粒DNA对水牛的免疫保护作用.方法:将血吸虫病非流行区8~10月龄健康水牛45头随机分为A组(SjC23-Hsp70+IL-12)、B组(SjC23+IL- 12)和C组(pVAX+IL-12),每组15头.每头牛经肩部肌注免疫3次,每次间隔28 d.末次免疫后28 d,每头牛感染日本血吸虫尾蚴1000条.解剖前2天及当天分别收集粪便1次,用定量法检测虫卵和毛蚴数.攻击感染后56天解剖所有水牛,经胸主动脉灌冲法收集成虫,计数成虫数,检测每克肝组织虫卵数.结果:A,B组与C组相比,分别获得45.70%和26.61%的减雌率,44.51%和25.84%的减虫率,41.10%和31.63%的减粪卵率,48.11%和38.07%的减毛蚴率及43.39%和31.95%的减肝卵率.A组的5个率均比B组高(P<0.05).结论:用SjC23-Hsp70 DNA疫苗和IL-12联合免疫水牛可获得明显的免疫保护作用.%Objective: To determine the immune-protective effect of Japan Schistosoma (Chinese mainland strain) 23 kD membrane protein-heat shock protein (SjC23-Hsp70) DNA vaccine plus adjuvant-induced interleukin-12 (IL-12) plasmid DNA on Schistosoma japonicum infection in water buffalos. Methods: Forty-five health water buffalos (8-10 months old) in non-endemic area of schistosomiasis were randomly assigned into group A (SjC23-Hsp70+IL-12, 300 μg), group B (SjC23+IL-12, 300 μg) and group C (pVAX+IL-12, 300 μg), 15 in each group. Each buffalo was immuned by shoulder intramuscular injection for 3 times, at an interval of 28 days. Twenty-eight days after the last immunization, each buffalo was infected with 1000 Japan cercariae of Schistosoma. Fecal examinations were conducted 2 days and 1 day before the perfusion, and on the day of perfusion. The number of hatching miracidia and eggs per gram feces was recorded. Fifty-six days after the infection, the buffalos were sacrificed and perfused via the descending

  6. 3种青蒿素衍生物对日本血吸虫吡喹酮抗性株童虫的体内作用效果观察%In-vivo efficacy of three artesiminin derivatives against schistosomulum of praziquantel-resistant Schistosoma japonicum

    Institute of Scientific and Technical Information of China (English)

    卢萍; 汪伟; 曲国立; 戴建荣; 梁幼生

    2014-01-01

    目的:观察3种青蒿素衍生物双氢青蒿素、青蒿琥酯和蒿甲醚对日本血吸虫吡喹酮抗性株童虫的体内作用效果。方法以经11轮亚治疗剂量吡喹酮筛选的日本血吸虫为吡喹酮抗性株,以未暴露于吡喹酮的日本血吸虫作为吡喹酮敏感株,收集2虫株尾蚴感染小鼠,以300 mg/kg双氢青蒿素、青蒿琥酯和蒿甲醚对感染后7~8 d童虫分别进行2次灌服用药(总剂量600 mg/kg),所有小鼠于感染后45 d解剖,收集小鼠体内成虫并计数,计算减虫率和减雌率。结果300 mg/kg双氢青蒿素、蒿甲醚和青蒿琥酯2日疗法(总剂量600 mg/kg)对日本血吸虫吡喹酮敏感株7~8 d童虫的减虫率为69.8%~71.0%,减雌率为75.4%~79.8%;对日本血吸虫吡喹酮抗性株7~8 d童虫的减虫率为64.6%~66.1%,减雌率为69.3%~71.1%,差异均无统计学意义(均P>0.05)。结论日本血吸虫吡喹酮抗性株对青蒿素类衍生物双氢青蒿素、青蒿琥酯和蒿甲醚依然敏感,青蒿素衍生物与吡喹酮在日本血吸虫中不存在交叉抗药性。%Objective To evaluate the in-vivo efficacy of three artemisinin derivatives artemether, artesunate and dihydroartemisinin against schistosomulum of praziquantel-resistant Schistosoma japonicum,. Methods The S. japonicum subjected to subcurative dose of praziquantel for 11 rounds was served as a praziquantel-resistant strain, while the field-derived strain without exposure to praziquantel was served as a praziquantel-susceptible strain. The mice infected with the two strains of cercaria were treated with artemether, artesunate and dihydroartemisinin at a single dose of 300 mg/kg by gavage in days 7 and 8 post-infection, respectively. All mice were dissected 45 days post-infection, and the adult worms were collected to estimate worm and female worm burden reductions caused by drug treatment. Results Administration of artemether, artesunate and dihydroartemisinin at a single

  7. 蒿甲醚对感染小鼠体内埃及血吸虫超微结构的影响%Ultrastructural Alterations of Adult Schistosoma haematobium Harbored in Mice Following Artemether Administration

    Institute of Scientific and Technical Information of China (English)

    肖树华; J(U)rg UTZINGER; 沈炳贵; Marcel TANNER; Jacques CHOLLET

    2006-01-01

    目的 观察蒿甲醚对小鼠体内埃及血吸虫成虫超微结构的损害.方法 8只小鼠于感染埃及血吸虫尾蚴后81 d用单剂蒿甲醚400 mg/kg口服治疗.治后24 h、3 d、7 d和14 d各剖杀2只小鼠,用灌注法收集血吸虫,并按常规方法固定和处置虫体,作透射电镜观察.从另2只未治疗的感染小鼠体内取虫作对照.结果 蒿甲醚对血吸虫皮层超微结构的损害主要是皮层基质的肿胀、溶解和空泡变化,基底膜消失和部份受损皮层破裂;在感觉器和皮层结节中,常见其内部结构广泛溶解.在肌层、实质组织、合体细胞和肠管上皮细胞中,查见局灶性或广泛的溶解、粗面内质网减少及线粒体空泡变化和变性.雌虫卵黄细胞的严重变化是空泡变化、粗面内质网减少、卵黄球融合以及受损卵黄细胞破溃等.上述雌、雄虫变化于感染小鼠用蒿甲醚治疗后24 h即可见到,并逐渐加重,3~7 d后最重.治后14 d,部分雌、雄虫仍示有超微结构的损害,但同时亦观察到受损虫组织的恢复.结论 蒿甲醚对埃及血吸虫成虫的皮层和皮层下组织具有广泛和严重的超微结构损害.%Objective To perform a temporal examination of ultrastructural alterations in adult Schistosoma haematobium due to artemether Methods Eight mice infected with 100-120 S. haematobium cercariae for 81 days were treated intragastrically with 400 mg/kg artemether. At 24 hours, 3, 7 and 14 days post-treatment, groups of 2 mice were sacrificed and schistosomes collected by the perfusion technique. Worm samples were fixed and examined by transmission electron microscopy. Schistosomes were also obtained from 2 untreated mice that served as control.Results Typical ultrastructural alterations included swelling, lysis and vacuolization of the tegumental matrix, and disappearance of basal membrane. In sensory organelles and tubercles, there was extensive or local lysis of internal structure. In the

  8. Clinical Diagnosis and Treatment in an Outbreak of Fasciola gigantica Infection in Yunnan Province%云南省首次暴发巨片形吸虫感染的临床诊治分析

    Institute of Scientific and Technical Information of China (English)

    顾伟; 苏慧勇; 邹静; 李芹翠; 陈白云; 林灿松; 焦建明

    2012-01-01

    Objective To carry out clinical diagnosis and treatment of Fasciola gigantica infection during an outbreak in Yunnan Province. Methods Data on epidemiololgy, diagnosis and treatment were collected from 27 patients. A questionnaire survey to the patients and partial villagers was carried out including history of raw food-eating and pet-raising. Animal feces were collected and examined by precipitation method and eggs incubation method. Cattle from two patients families were dissectd to find Fasciola infection. Serum samples from patients, family members, and villagers were detected. Possible intermediate snails were collected from the vicinity of streams and ponds in 15 villages where patients lived. Results The earliest onset of symptoms among the patients was on March 10, 2011 and the last case was on January 10, 2012. The clinical manifestations were mainly fever with unknown reason, decreasing hemoglobin, increasing eosinophils, and hepatosplenomegaly. No parasite eggs were found in feces. Antibodies against F. gigantica were positive by ELISA in 23 patients. Fasciola eggs were then found in 4 patients' feceson February 16, 2012. F. gigantica eggs and adults were found in the hepatobiliary system of dissected cattle. Triclabendazole [10mg/(kg·d) x2 d] was administered orally for the patients and the clinical symptoms eased. Snails including Physa acuta, Radix swinhoei and Galba pervia were collected and cercariae were found in only one snail. Conclusion An outbreak of F. gigantica infection has been confirmed and the diagnosed cases effectively treated with triclabendazole.%目的 分析云南省首次暴发巨片形吸虫(Fasciola gigantica)感染的临床诊治过程,为今后对该病的诊治提供参考.方法 收集27例患者的发病、诊断和治疗资料.对患者及其家属和部分村民进行问卷调查,内容包括生食史和宠物饲养史等.采集各类动物粪便,使用粪便沉淀法和虫卵孵育法进行粪检.

  9. Estudos sobre a Esquistosomose em Pernambuco, Brasil

    Directory of Open Access Journals (Sweden)

    Aggeu Magalhães

    1940-01-01

    Full Text Available Os autores referem os resultados dos estudos sobre esquistosomose realisados, em Pernambuco, de Novembro de 1938 a Dezembro de 1939. Não se extendem em discussão, nem comentarios, tampouco, relacionam suas verificações com o que já foi relatado sobre o assunto em trabalhos nacionais e estrangeiros, pelo fato de que, não se trata de um resultado definitivo e sim de atividades que irão proseguir. Os estudos sistematicos em torno da endemia esquistosomica foram executados em duas localidades diversas pela população e pela situação geografica e ecologica. Pontezinha é uma povoação de 1200 habitantes localizada proximo a um conjunto de charcos e lagõas de agua dôce onde pululam caramujos do tipo olivaceus de Spix, e apresenta uma taxa de infestação de 21,4% para individuos do sexo masculino, e de 14,7% para os do sexo feminino. A distribuição por grupos de idade mostra que a incidencia cresce até o grupo de 16 a 20 anos de idade, quando atinge a percentagem de 37,8%, para decrescer em seguida. Em Vitoria a incidencia foi maior nos indivíduos do sexo feminino, atingindo a taxa de 41,4%, dando o sexo masculino a taxa de 36,9%. Por idade a percentagem maxima é atingida pelo grupo de 11 a 15 anos. Vitoria é uma cidade de 1500 habitantes, construida á margem do rio Tapacurá, onde se encontram numerosos caramujos do tipo centimetralis Lutz. A divergencia de incidencia corre por conta dos habitos da população e pela utilização que ela faz do rio, sendo maior em Vitoria porque a proximidade do rio facilita o uso de suas aguas para banho e serviços domesticos, condicionando este ultimo fato, a maior infestação das mulheres. O estudo da frequencia da infestação dos caramujos por cercarias de diversos trematodios, permite suspeitar uma relação inversa entre a taxa de infestação e o diametro maximo atingido pelos caramujos, parecendo este fato confirmar os trabalhos de Vianna Martins sobre a identidade dos hospedeiros

  10. 云南省大理州大片形吸虫群体感染26例分析%Twenty six cases of human Fasciola gigantica infection in Dali, Yunnan province

    Institute of Scientific and Technical Information of China (English)

    陈木新; 罗家军; 陈家旭; 艾琳; 许学年; 吕山; 焦建明; 苏慧勇; 臧伟; 诸廷俊; 蔡玉春

    2012-01-01

    same epidemiological characteristics.ELISA detection was used in the 26 patients,family members and other healthy population,the results of all the 26 patients were positive(100.0%,26/26) ; the positive rates of the 57 family members and other health people of the same village were 31.6% (18/57) and 17.1% (6/35),respectively.The results of sequencing and BLAST program showed that the pathogen was Fasciola gigantica with the similarity between 99%-100%.PCR amplification also confirmed that the eggs were Fasciola gigantica eggs with an approximately 1000 bp band on agarose gel.After treatment with Triclabendazole,body temperature of the patients dropped to normal and symptoms improved markedly.Moreover,329 Limnaea peregra snails were collected including 5 ones with redia and one-tailed cercariae which were preliminary identified as the larva of Fasciola gigantica.There were also eggs of Fasciola gigantica detected in one stool of cattle and one of goat.Conclusions Eating raw food is the leading cause of the onset of the disease.Triclabendazole is the drug of choice to treat Fasciolasis.Health education should be strengthened by government and disease prevention and control departments in order to make the local residents to understand the potential hazard of eating raw aquatic vegetable and drinking unboiled water,which is the key to prevent the occurrence of the disease.