WorldWideScience

Sample records for cercaria

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

    Directory of Open Access Journals (Sweden)

    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

    CERN Document Server

    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. Localization of the cystogenous glands of Opisthorchis viverrini cercariae.

    Science.gov (United States)

    Arunsan, Patpicha; Donthaisong, Chalermlap; Suwannatrai, Kulwadee; Prasopdee, Sattrachai; Kulsantiwong, Jutharat; Suwannatrai, Apiporn; Boonmars, Thidarut; Welbat, Jariya Umka; Oopachitakul, Songpol; Tesana, Smarn

    2014-03-01

    Opisthorchiasis in northeastern Thailand is an important etiology of cholangiocarcinoma. To form the infectious stage, free swimming cercariae penetrate cyprinid fish, shed their tails, and then secret a cystic substance to cover their larval stage to form metacercariae in the fish body. We determined the location of the cystogenous glands in Opisthorchis viverrini cercariae. The cercariae and metacercariae were obtained from the naturally infected snail host, Bithynia siamensis goniomphalos and from cyprinid fish, respectively. The cyst walls of the metacercariae were separated and used to immunize inbred male BALB/c mice to obtain cyst wall antibodies. The general characteristics of the O. viverrini cercariae and metacercariae were studied by hematoxylin and eosin (H&E) staining of sections. The location and ultrastructure of the cystogenous glands of cercariae were studied by immunoperoxidase, immunofluorescence and transmission electron microscopy. The structures and organelles of cercariae and metacercariae could be identified, but the cystogenous glands could not be detected in H&E sections. The immunoperoxidase and immunofluorescence sections revealed positive reactions for cystogenous glands predominanted in the lateral part of the cercariae and were clearly seen in the cyst wall of the metacercariae. The ultrastructure of the cystogenous glands contained semitranslucent electron dense oval shaped granules. If interference occurs during the formation of the cysts by fish immune response, the metacercariae may not develop to maturity. It may be easily digested or degraded by human stomach acid and pepsin. This may be an efficient method for control of O. viverrini infection which requires further detailed study.

  4. Small estuarine fishes feed on large trematode cercariae: Lab and field investigations

    Science.gov (United States)

    Kaplan, A.T.; Rebhal, S.; Lafferty, K.D.; Kuris, A.M.

    2009-01-01

    In aquatic ecosystems, dense populations of snails can shed millions of digenean trematode cercariae every day. These short-lived, free-living larvae are rich in energy and present a potential resource for consumers. We investigated whether estuarine fishes eat cercariae shed by trematodes of the estuarine snail Cerithidea californica. In aquaria we presented cercariae from 10 native trematode species to 6 species of native estuarine fishes. Many of these fishes readily engorged on cercariae. To determine if fishes ate cercariae in the field, we collected the most common fish species, Fundulus parvipinnis (California killifish), from shallow water on rising tides when snails shed cercariae. Of 61 killifish, 3 had recognizable cercariae in their gut. Because cercariae are common in this estuary, they could be frequent sources of energy for small fishes. In turn, predation on cercariae by fishes (and other predators) could also reduce the transmission success of trematodes. ?? 2009 American Society of Parasitologists.

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

    Science.gov (United States)

    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.

  6. Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand

    Science.gov (United States)

    Chontananarth, Thapana; Tejangkura, Thanawan; Wetchasart, Napat; Chimburut, Cherdchay

    2017-01-01

    The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible. PMID:28285506

  7. Morphological Characteristics and Phylogenetic Trends of Trematode Cercariae in Freshwater Snails from Nakhon Nayok Province, Thailand.

    Science.gov (United States)

    Chontananarth, Thapana; Tejangkura, Thanawan; Wetchasart, Napat; Chimburut, Cherdchay

    2017-02-01

    The prevalence of cercarial infection in freshwater snails and their evolutionary trends were studied in Nakhon Nayok province, Thailand. A total of 2,869 individual snails were examined for parasitic infections. The results showed that 12 snail species were found to host larval stages of trematodes with an overall prevalence of 4.7%. The infected specimens included 7 types at the cercarial stage; cercariae, megalurous cercariae, echinostome cercariae, furcocercous cercariae, parapleurolophocercous cercariae, virgulate cercariae, and xiphidiocercariae. Regarding molecular identification, ITS2 sequence data of each larval trematode were analyzed, and a dendrogram was constructed using the neighbor-joining method with 10,000 replicates. The dendrogram was separated into 6 clades (order/family), including Echinostomatida/Echinostomatidae, Echinostomatida/Philophthalmidae, Opisthorchiida/Heterophyidae, Plagiorchiida/Prosthogonimidae, Plagiorchiida/Lecithodendriidae, and Strigeatida/Cyathocotylidae. These findings were used to confirm morphological characteristics and evolutionary trends of each type of cercariae discovered in Nakhon Nayok province. Furthermore, this investigation confirmed that the ITS2 data of cercariae could be used to study on phylogenetic relationships or to determine classification of this species at order and/or family level when possible.

  8. [Isolation of the cercaria Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 (Diplostomatidae) from fresh water mollusks of the Crimea].

    Science.gov (United States)

    Sten'ko, R P

    1976-01-01

    Data on the biology and morphology of cercariae of Diplostomum phoxini (Faust, 1918) Arvy et Buttner, 1954 are given. The cercariae were found in Radix auricularia from the middle part of the Burulcha river (Ukranian SSR, Crimea). In November, 1974 the invasion extensity of mollusks was 16.3%. No cercariae were found in spring and summer samples.

  9. 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

    reported for free-living invertebrates inhabiting benthic ecosystems. These estimates would be much higher if they included all trematode species in an ecosystem, and not just single-species values. Overall, results suggest that trematode cercariae represent potentially important paths of energy flow....... 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Kinetics of the cercaria-schistosomulum transformation in vivo

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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.

  13. Behavioral analysis of Microphallus turgidus cercariae in relation to microhabitat of two host grass shrimp species (Palaemonetes spp.).

    Science.gov (United States)

    O'Leary, Patricia A; Pung, Oscar J

    2017-01-24

    The behavior of Microphallus turgidus cercariae was examined and compared to microhabitat selection of the second intermediate hosts of the parasite, Palaemonetes spp. grass shrimp. Cercariae were tested for photokinetic and geotactic responses, and a behavioral ethogram was established for cercariae in control and grass shrimp-conditioned brackish water. Photokinesis trials were performed using a half-covered Petri dish, and geotaxis trials used a graduated cylinder. Both photokinesis and geotaxis trials were performed in lighted and unlighted conditions. In 9 of 10 photokinesis experiments, over half of the cercariae swam horizontally under the covered half of a Petri dish in both the lighted and the unlighted trials. However, movement of the cercariae to the covered half of the dish was highest (81.4%) when the parasites were exposed to light. In the geotaxis study, most cercariae were found in the bottom third of a graduated cylinder water column in both the lighted and unlighted trials. The most frequently observed activity of individual cercariae in a lighted Petri dish was swimming on the bottom of the dish. Activity patterns of the cercariae were not affected by shrimp-conditioned water. Movement of the cercariae away from light into dark, active swimming at or near the bottom of the water column, and a lack of response to host odors suggest that the cercariae utilize search patterns that place the parasite in the preferred microhabitat of the principle second intermediate host, the grass shrimp P. pugio.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. 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.

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

    Science.gov (United States)

    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.

  18. 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.

  19. A review of the currently recognised zoogonid cercariae, including the identification and emergence ecology of Cercaria capricornia XI (Digenea: Zoogonidae) from Nassarius olivaceus (Gastropoda: Nassariidae) in Central Queensland, Australia.

    Science.gov (United States)

    Barnett, Leonie J; Miller, Terrence L; Cribb, Thomas H

    2014-08-01

    In the present study, we review the known zoogonid cercariae, summarise their life-cycles and first intermediate host distributions, and present a new cercaria, Cercaria capricornia XI (Digenea: Zoogonidae), which was found in one of three nassariid gastropods, Nassarius olivaceus (Bruguière), surveyed in the intertidal zone in the Capricornia region of Central Queensland, Australia. Morphological data and molecular analysis of the ITS2 rDNA region support placement of this cercaria in the family Zoogonidae but do not allow any further resolution of its identity. There are now fifteen cercariae described as belonging to the Zoogonidae; thirteen of these, including the present species, infect neogastropods as first intermediate hosts and two use vetigastropods. This study reinforces the pattern that the Nassariidae is by far the most commonly reported family for the Zoogonidae. Given its richness we predict that the Nassariidae will prove to harbour many more zoogonid species.

  20. Experimental infection of Opisthorchis viverrini cercariae to the cyprinid fish, Barbonymus gonionotus.

    Science.gov (United States)

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

    2014-08-01

    Opisthorchis viverrini is an important public health problem, a major cause of cholangiocarcinoma in the Greater Mekong subregion including Lao PDR, Cambodia, Vietnam and Thailand. Humans acquire the infection by consumption of raw, fermented or partially cooked freshwater cyprinid fish containing infective metacercariae. This study examined the effect of cercarial infection dosage (25-200 cercariae), age (1-60 day) and size (1-24mm) of Barbonymus gonionotus fish on infection success of O. viverrini cercariae. Additionally, the site of cyst formation of O. viverrini cercariae and subsequent development to the metacercariae was examined. The result showed that cercarial infection dose (F4,95=8.52, Pviverrini metacercariae recovery with in every additional fish age, the O. viverrini metacercarial recovery rate increased by 5.4% (Pviverrini cercarial infection dosage, and age and size of fish were important determinants for a successful infection to fish.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y.-E.; Jiang, C.-F.; Han, J.-J.; Li, Y.-L. (Tongji Medical Univ., Wuhan (China). Dept. of Parasitology); Ruppel, A. (Institute for Tropical Hygiene, Heidelberg (Germany))

    1993-06-01

    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 [mu]Watt.min/cm[sup 2]). 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).

  2. Do parasitic trematode cercariae demonstrate a preference for susceptible host species?

    Directory of Open Access Journals (Sweden)

    Brittany F Sears

    Full Text Available Many parasites are motile and exhibit behavioural preferences for certain host species. Because hosts can vary in their susceptibility to infections, parasites might benefit from preferentially detecting and infecting the most susceptible host, but this mechanistic hypothesis for host-choice has rarely been tested. We evaluated whether cercariae (larval trematode parasites prefer the most susceptible host species by simultaneously presenting cercariae with four species of tadpole hosts. Cercariae consistently preferred hosts in the following order: Anaxyrus ( = Bufo terrestris (southern toad, Hyla squirella (squirrel tree frog, Lithobates ( = Rana sphenocephala (southern leopard frog, and Osteopilus septentrionalis (Cuban tree frog. These host species varied in susceptibility to cercariae in an order similar to their attractiveness with a correlation that approached significance. Host attractiveness to parasites also varied consistently and significantly among individuals within a host species. If heritable, this individual-level host variation would represent the raw material upon which selection could act, which could promote a Red Queen "arms race" between host cues and parasite detection of those cues. If, in general, motile parasites prefer to infect the most susceptible host species, this phenomenon could explain aggregated distributions of parasites among hosts and contribute to parasite transmission rates and the evolution of virulence. Parasite preferences for hosts belie the common assumption of disease models that parasites seek and infect hosts at random.

  3. [Characterization of the cercaria of Bucephalus polymorphus Baer, 1827 (Trematoda, Bucephalidae): chetotaxy and excretory system].

    Science.gov (United States)

    Wallet, M; Lambert, A

    1984-01-01

    We describe the excretory system and the chetotaxy of the cercaria of Bucephalus polymorphus Baer, 1827 which develops in Dreissena polymorpha (Lamellibranch, Dreissenidae) in South-East of France. We compare our observations with those realised in Poland and we discuss about the differences observed.

  4. Changes in surface glycosylation and glycocalyx shedding in Trichobilharzia regenti (Schistosomatidae) during the transformation of cercaria to schistosomulum

    Science.gov (United States)

    Řimnáčová, Jana; Turjanicová, Libuše; Bulantová, Jana; Horák, Petr

    2017-01-01

    The invasive larvae (cercariae) of schistosomes penetrate the skin of their definitive hosts. During the invasion, they undergo dramatic ultrastructural and physiological transitions. These changes result in the development of the subsequent stage, schistosomulum, which migrates through host tissues in close contact with host’s immune system. One of the striking changes in the transforming cercariae is the shedding of their thick tegumental glycocalyx, which represents an immunoattractive structure; therefore its removal helps cercariae to avoid immune attack. A set of commercial fluorescently labeled lectin probes, their saccharide inhibitors and monoclonal antibodies against the trisaccharide Lewis-X antigen (LeX, CD15) were used to characterize changes in the surface saccharide composition of the neuropathogenic avian schistosome Trichobilharzia regenti during the transformation of cercariae to schistosomula, both in vitro and in vivo. The effect of various lectins on glycocalyx shedding was evaluated microscopically. The involvement of peptidases and their inhibitors on the shedding of glycocalyx was investigated using T. regenti recombinant cathepsin B2 and a set of peptidase inhibitors. The surface glycocalyx of T. regenti cercariae was rich in fucose and mannose/glucose residues. After the transformation of cercariae in vitro or in vivo within their specific duck host, reduction and vanishing of these epitopes was observed, and galactose/N-acetylgalactosamine emerged. The presence of LeX was not observed on the cercariae, but the antigen was gradually expressed from the anterior part of the body in the developing schistosomula. Some lectins which bind to the cercarial surface also induced secretion from the acetabular penetration glands. Seven lectins induced the shedding of glycocalyx by cercariae, among which five bound strongly to cercarial surface; the effect could be blocked by saccharide inhibitors. Mannose-binding protein, part of the lectin pathway

  5. 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.

  6. The Epigenome of Schistosoma mansoni Provides Insight about How Cercariae Poise Transcription until Infection.

    Directory of Open Access Journals (Sweden)

    David Roquis

    Full Text Available Chromatin structure can control gene expression and can define specific transcription states. For example, bivalent methylation of histone H3K4 and H3K27 is linked to poised transcription in vertebrate embryonic stem cells (ESC. It allows them to rapidly engage specific developmental pathways. We reasoned that non-vertebrate metazoans that encounter a similar developmental constraint (i.e. to quickly start development into a new phenotype might use a similar system. Schistosomes are parasitic platyhelminthes that are characterized by passage through two hosts: a mollusk as intermediate host and humans or rodents as definitive host. During its development, the parasite undergoes drastic changes, most notable immediately after infection of the definitive host, i.e. during the transition from the free-swimming cercariae into adult worms.We used Chromatin Immunoprecipitation followed by massive parallel sequencing (ChIP-Seq to analyze genome-wide chromatin structure of S. mansoni on the level of histone modifications (H3K4me3, H3K27me3, H3K9me3, and H3K9ac in cercariae, schistosomula and adults (available at http://genome.univ-perp.fr. We saw striking differences in chromatin structure between the developmental stages, but most importantly we found that cercariae possess a specific combination of marks at the transcription start sites (TSS that has similarities to a structure found in ESC. We demonstrate that in cercariae no transcription occurs, and we provide evidences that cercariae do not possess large numbers of canonical stem cells.We describe here a broad view on the epigenome of a metazoan parasite. Most notably, we find bivalent histone H3 methylation in cercariae. Methylation of H3K27 is removed during transformation into schistosomula (and stays absent in adults and transcription is activated. In addition, shifts of H3K9 methylation and acetylation occur towards upstream and downstream of the transcriptional start site (TSS. We conclude

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Experimental exposure of adult San Marcos salamanders and larval leopard frogs to the cercariae of Centrocestus formosanus.

    Science.gov (United States)

    Huston, D C; Cantu, V; Huffman, D G

    2014-04-01

    The gill parasite Centrocestus formosanus (Trematoda: Heterophyidae) is an exotic parasite of concern in Texas because it has been shown to infect multiple threatened and endangered fish species. The purpose of this study was to determine if C. formosanus could present a threat to larval anurans, as well as threatened neotenic salamanders endemic to the spring-fed systems of Texas. We exposed adults of the San Marcos salamander Eurycea nana (Caudata: Plethodontidae) and tadpoles of the Rio Grande leopard frog Lithobates berlandieri (Anura: Ranidae) to the cercariae of C. formosanus . The San Marcos salamander showed no signs of metacercarial infection, suggesting that E. nana may be refractory to C. formosanus cercariae. Centrocestus formosanus readily infects the gills of leopard frog tadpoles, but the metacercariae apparently died prior to reaching maturity in our tadpoles.

  12. Analysis of trait mean and variability versus temperature in trematode cercariae: is there scope for adaptation to global warming?

    Science.gov (United States)

    Studer, A; Poulin, R

    2014-05-01

    The potential of species for evolutionary adaptation in the context of global climate change has recently come under scrutiny. Estimates of phenotypic variation in biological traits may prove valuable for identifying species, or groups of species, with greater or lower potential for evolutionary adaptation, as this variation, when heritable, represents the basis for natural selection. Assuming that measures of trait variability reflect the evolutionary potential of these traits, we conducted an analysis across trematode species to determine the potential of these parasites as a group to adapt to increasing temperatures. Firstly, we assessed how the mean number of infective stages (cercariae) emerging from infected snail hosts as well as the survival and infectivity of cercariae are related to temperature. Secondly and importantly in the context of evolutionary potential, we assessed how coefficients of variation for these traits are related to temperature, in both cases controlling for other factors such as habitat, acclimatisation, latitude and type of target host. With increasing temperature, an optimum curve was found for mean output and mean infectivity, and a linear decrease for survival of cercariae. For coefficients of variation, temperature was only an important predictor in the case of cercarial output, where results indicated that there is, however, no evidence for limited trait variation at the higher temperature range. No directional trend was found for either variation of survival or infectivity. These results, characterising general patterns among trematodes, suggest that all three traits considered may have potential to change through adaptive evolution.

  13. Multiple vaccinations with UV- attenuated cercariae in pig enhance protective immunity against Schistosoma japonicum infection as compared to single vaccination

    Directory of Open Access Journals (Sweden)

    Zhang Donghui

    2011-06-01

    Full Text Available Abstract Background Schistosomiasis japonica is a major public health problem in the endemic areas of China, the Philippines, and Indonesia. To date, a vaccine has not been developed against this disease but immunization with UV-attenuated cercariae can induce a high level of protective immunity in Landrace/Yorkshire/Duroc crossbred pigs. To compare the efficacy of a single vaccination and multiple vaccinations with UV-attenuated Schistosoma japonicum cercariae, two groups of pigs received either one or three exposures to 10,000 cercariae attenuated with 400 μw UV. Results Pigs with a single immunization had a 59.33% reduction in adult worm burden, a 89.87% reduction in hepatic eggs and a 86.27% reduction in fecal eggs at eight weeks post-challenge (P P Conclusion The high levels of protection against S. japonicum infection can be achieved with a UV-attenuated vaccine in pigs, and that three vaccinations were possibly more effective than a single vaccination. Moreover, triple vaccinations evoked a more vigorous IFN-γ response and a stronger antibody-mediated response, especially an increase in the levels of IgG2 antibodies.

  14. Experimental and molecular study of cercariae of Clinostomum sp. (Trematoda: Clinostomidae) from Biomphalaria spp. (Mollusca: Planorbidae) in Brazil.

    Science.gov (United States)

    Pinto, H A; Caffara, M; Fioravanti, M L; Melo, A L

    2015-02-01

    Despite the large number of reports of species of Clinostomum from vertebrate hosts in South America, studies evaluating the molluscan transmitters of these parasites are scarce. In the present study, clinostomatoid cercariae shed from 0.02% (4/17,485) specimens of Biomphalaria spp., collected at the Pampulha reservoir, Belo Horizonte, Minas Gerais, Brazil, were used for experimental infection of Poecilia reticulata . Samples of cercariae from molluscs and metacercariae experimentally obtained from fish were subjected to morphological and molecular analyses and compared with species of Clinostomum reported in the Americas. The cercariae and metacercariae, here identified as Clinostomum sp., present general morphology similar to that reported for Clinostomum marginatum , however, from molecular point of view, differ significantly from North American C. marginatum and other species of Clinostomum reported in South America. These results suggest that the diversity of Clinostomum found in Brazil may be underestimated. Additional studies aimed at molecular characterization of South American species of Clinostomum, including the finding of specimens with sequences similar to that reported for C. marginatum in North America are required.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Machado-Silva José Roberto

    2000-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Schistosoma mansoni: the effect of dexamethasone on the cercaria-schistosomulum transformation, in vivo Schistosoma mansoni: o efeito da dexametasona na transformação da cercaria em esquistossômulo, in vivo

    Directory of Open Access Journals (Sweden)

    Alan Laue de Melo

    1994-02-01

    Full Text Available Treatment with dexamethasone (DMS in the early phases of the experimental Schistosoma mansoni infection causes an indirect effect on the cercaria-schistosomulum transformation process. This is observed when naive albino mice are treated with that drug (50 mg/Kg, subcutaneously and infected intraperitonealy 01 hour later with about 500 S. mansoni cercariae (LE strain. An inhibition in the host cell adhesion to the larvae, with a simultaneous delay in the cercaria-schistosomulum transformation, is observed. This effect is probably due to a blockade of the neutrophil migration to the peritoneal cavity of mice, by an impairment of the release of chemotactic substances. Such delay probably favors the killing of S. mansoni larvae, still in the transformation process, by the vertebrate host defenses, as the complement system.O tratamento com dexametasona (DMS nas fases iniciais da infecção experimental com S. mansoni leva a um efeito indireto sobre o processo de transformação da cercária em esquistossômulo, quando camundongos isentos de infecção são tratados com esta droga (50 mg/ kg, subcutâneamente e, 01 hora depois, são infectados intraperitonealmente com cerca de 500 cercárias de S. mansoni (cepa LE. Foi observada uma significativa redução na adesão de células do hospedeiro às larvas, com um atraso simultâneo no processo de transformação das cercárias em esquistossômulos. Este efeito é, provavelmente, devido a um bloqueio inespecifícico da migração neutrofilica para a cavidade peritoneal, através de um bloqueio da liberação de substâncias quimio-táticas. Tal atraso pode permitir a morte das larvas de S. mansoni (ainda em processo de transformação pelas defesas do hospedeiro vertebrado, como o sistema do complemento.

  19. 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.

  20. 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.

  1. The lethality of Euphorbia conspicua to adults of Biomphalaria glabrata, cercaria of Schistosoma mansoni and larvae of Artemia salina.

    Science.gov (United States)

    dos Santos, Aldenir F; de Azevedo, Denise P L; dos Santos Mata, Rosalina da C; de Mendonça, Dina I M Dinis; Sant'Ana, Antônio E Goulart

    2007-01-01

    Leaf extracts of Euphorbia conspicua (Euphorbiaceae), together with the latex and fractions derived therefrom, were evaluated for their molluscicidal and cercaricidal activities and their toxicities to brine shrimps. Whilst the leaf extracts were inactive against Biomphalaria glabrata, the latex, its triterpenic fraction and irritant fractions I and II exhibited high activities against adult snails with LC90 values of 4.87, 10.55, 0.64 and 0.10 microg/mL, respectively. The latex and its derived fractions were considered lethal to the cercaria of Schistosoma mansoni at concentrations of 100 microg/mL. The toxicities of the latex and the irritant fractions, but not of the triterpenic fraction, against Artemia salina were high with LC50 values < 10 microg/mL. The possible application of the latex of E. conspicua as an alternative natural molluscicide is considered.

  2. 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).

  3. 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

    Directory of Open Access Journals (Sweden)

    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

  4. 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).

  5. 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.

  6. 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.

  7. 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.

  8. Digital In-line Holography for Schistosoma Cercariae Detection%同轴数字全息用于血吸虫尾蚴检测研究

    Institute of Scientific and Technical Information of China (English)

    王凤鹏; 李亿保; 谢应茂; 范小林; 郭金水

    2012-01-01

    The traditional microscope is not suitable to observe the schistosoma cercariae which usually floating on the water surface, because it needs an optical focusing process and the wobble or fluctuation of the water surface is difficult to avoid. The basic concept and procedure of digital in-line holography based on convolution are shown mainly for schistosoma cercariae detection. An auto-focus algorithm based on wavelet transform was improved. The max amplitude of high-frequency coefficients in the focal windows was used to evaluate the definition of the reconstructed image instead of the sum of high-frequency coefficients. The evaluation function was maximal only when the reconstructed distance equal to the recording distance in the simulated experiment, which shows the accuracy of the improved algorithm. The experimental device of digital in-line holography was designed for schistosoma cercariae detection. The experimental results show that the auto-focusing method based on wavelet transform can be used in digital holography, and the digital in-line holography can be used to detect schistosoma cercariae when the water surface is fluctuant. The reconstructed image resolution is equivalent to the resolution of digital microscope with 1X micro lens, and the bifurcated tail of schistosoma cercariae can be observed clearly.%由于水的表面易出现抖动或波动情况,而传统的显微镜成像需要精确的光学焦聚过程,因此不适于观察漂浮于水表面的血吸虫尾蚴.本文论述了用同轴数字全息检测血吸虫尾蚴的基本原理.通过对再现像进行小波分析发现,偏离焦点时的小波变换高频系数的幅值比聚焦时要小得多.针对这一特点,本文对小波变换清晰度评价函数进行了改进,将原来利用高频系数之和改为利用聚焦窗口中高频系数的最大幅值为清晰度评价依据.在模拟实验结果中清晰度评价函数极大值出现在再现距离与记录距离相等处,说明

  9. Exceptionally high prevalence of infection of Bithynia siamensis goniomphalos with Opisthorchis viverrini cercariae in different wetlands in Thailand and Lao PDR.

    Science.gov (United States)

    Kiatsopit, Nadda; Sithithaworn, Paiboon; Saijuntha, Weerachai; Boonmars, Thidarut; Tesana, Smarn; Sithithaworn, Jiraporn; Petney, Trevor N; Andrews, Ross H

    2012-03-01

    The carcinogenic liver fluke, Opisthorchis viverrini, requires Bithynia snail intermediate hosts in its life cycle. However, the prevalence of O. viverrini in snail intermediate hosts is typically low (Thailand and The Lao People's Democratic Republic (Lao PDR) and reported high-prevalence levels of O. viverrini. The highest-prevalence levels per locality were 6.93% (mean = 3.04%) in Thailand and 8.37% (mean = 2.01%) in Lao PDR; 4 of 13 localities examined showed prevalence higher than any prevalence previously recorded. The number of cercariae infecting snails and their prevalence were positively correlated with the size of the snails. High prevalence occurred in the Songkram River wetland (Thailand) and the Nam Ngum River wetland (Lao PDR). Our results show that transmission of O. viverrini from humans as well as animal reservoir hosts to snail intermediate hosts is ongoing and potentially increasing in endemic areas across Thailand and Lao PDR.

  10. 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.

  11. In vitro effects of EGCG on Schistosoma japonicum cercariae%表没食子儿茶素没食子酸酯(EGCG)体外抗日本血吸虫尾蚴作用的研究

    Institute of Scientific and Technical Information of China (English)

    冯金梅; 袁发浒; 刘锴; 张泽华; 胡松; 邱文洪; Stephen Hsu; 宋文剑

    2016-01-01

    日本血吸虫尾蚴具有体外杀伤作用,发生的形态结构可能影响其侵袭宿主皮肤的能力.%Objectives To investigate whether epigallocatechin-3-gallate (EGCG) kills Schistosoma japonicum cercariae in vitro and its effects on the ultrastructure of those cercariae in order to evaluate whether EGCG protects against infection with S.japonicum cercariae.Methods Cercariae of S.japonicum were placed in distilled water (control group) or dif ferent concentrations of EGCG (0.2% and 1 %).Cercariae were treated for 30 and 60 min and then observed with a dissecting microscope.Cercariae that were treated for 30 min were also observed using scanning electron microscopy.Male BALB/c mice,6-8 weeks of age,were randomly divided into tlree groups with six animals each:group Ⅰ (control group,infected with S.japonicurn cercariae treated with 0% EGCG for 30 min),group Ⅱ (infected with S.japonicum cercariae treated with 0.1 % EGCG for 30 min),and group Ⅲ (infected with S.japonicum cercariae treated with 1% EGCG for 30 min).All experimental mice were anesthetized and percutaneously infected with 30 cercariae of S.japonicum that were placed on shaved abdominal skin.The animals were maintained in conventional animal housing at the Labo ratory Animal Center of Jianghan University,China.All mice were given standard rodent food pellets and water ad libitum.At six weeks post-infection,the mice were sacrificed and adult worms of S.japonicum were collected,and the rate of infection,the average worm burden,and the rate of worm clearance were calculated.Results Under a dissecting microscope,S.japonicum cercariae treated with 0% EGCG for 30 min (the controls) had a normal morphology and they moved freely,while cercariae treated with 0% EGCG for 60 min were rigid,curled up into a ball,and not moving.Cercariae that were treated with 0.2 % or 1% EGCG for 30 min were highly active,their tails lashed rapidly,they twitched,and their bodies were deformed

  12. Experimental study on a slow-release suspension of bleaching powder to kill schistosome cercariae%漂白粉漂浮缓释剂杀灭日本血吸虫尾蚴的实验研究

    Institute of Scientific and Technical Information of China (English)

    刘德祥; 钟秀丽

    2011-01-01

    Objective To investigate the effectiveness of a slow-release suspension of bleaching powder at killing schistosome cercariae.Methods In still water indoors, the release of available chlorine by a suspension of bleaching powder was observed.Suspensions were prepared with different concentrations of available chlorine and poured into a petri dish.Living cercariae were placed in the dish, and the survival or death of cercariae was observed under a dissecting microscope.Mice were infected with the cercariae and dissected 35 days later; worms were collected and the parasite load was calculated.Results In water, the slow-release suspension of bleaching powder had an available chlorine concentration that effectively killed cercariae for 40 days.Fifty percent of the formulation's particles were floating on the water surface as of day 60.An available chlorine concentration of 1.0 mg/L and 0.5 mg/L killed cercaria in 10 min.Mice infected with cercariae treated with bleaching powder (0.5-0.125 mg/L available chlorine) had significantly lower parasite load than did the control group(P<0.01).Conclusion A slow-release suspension of bleaching powder with an available chlorine concentration of 0.5 mg/L in water was effective at killing cercariae.As of day 60, 50% of the formulation's particles were floating on the water surface.%目的 观察漂白粉漂浮缓释剂对日本血吸虫尾蚴的杀灭效果.方法 在室内静水条件下观察漂白粉漂浮缓释剂的漂浮和释出有效氯情况;将漂白粉缓释剂按有效氯配制成不同浓度,注入培养板中,移入活尾蚴,解剖镜下观察尾蚴的存活时间;用不同浓度的有效氯杀蚴后感染小鼠,35 d解剖,收集成虫,计算鼠的虫负荷.结果 漂白粉漂浮缓释剂在水中释出有效氯有效杀灭尾蚴时间可达40 d,50%缓释剂颗粒在水面漂浮的时间可达60 d;有效氯浓度在1.0和0.5 mg/L时10 min 100%杀死尾蚴,有效氯浓度0.25和0.125 mg/L 30 min 100%

  13. Secretory glands in cercaria of the neuropathogenic schistosome Trichobilharzia regenti - ultrastructural characterization, 3-D modelling, volume and pH estimations

    Directory of Open Access Journals (Sweden)

    Koberna Karel

    2011-08-01

    Full Text Available Abstract Background Cercariae of schistosomes employ bioactive molecules for penetration into their hosts. These are released from specialized unicellular glands upon stimuli from host skin. The glands were previously well-described in the human pathogen Schistosoma mansoni. As bird schistosomes can also penetrate human skin and cause cercarial dermatitis, our aim was to characterize the architecture and ultrastructure of glands in the neurotropic bird schistosome Trichobilharzia regenti and compare it with S. mansoni. In the context of different histolytic enzymes used by these two species, we focused also on the estimations of gland volumes and pH in T. regenti. Results The architecture and 3-D models of two types of acetabular penetration glands, their ducts and of the head gland are shown here. We characterized secretory vesicles in all three gland types by means of TEM and confirmed accuracy of the models obtained by confocal microscopy. The results of two independent approaches showed that the glands occupy ca. one third of cercarial body volume (postacetabular glands ca. 15%, circumacetabular 12% and head gland 6%. The inner environment within the two types of acetabular glands differed significantly as evidenced by dissimilar ability to bind fluorescent markers and by pH value which was higher in circumacetabular (7.44 than in postacetabular (7.08 glands. Conclusions As far as we know, this is the first presentation of a 3-D model of cercarial glands and the first exact estimation of the volumes of the three gland types in schistosomes. Our comparisons between T. regenti and S. mansoni implied that the architecture and ultrastructure of the glands is most likely conserved within the family. Only minor variations were found between the two species. It seems that the differences in molecular composition have no effect on general appearance of the secretory cells in TEM. Fluorescent markers employed in this study, distinguishing between

  14. An ultrastructural study of excretory system development in the cercariae of Prosorhynchoides gracilescens (Rudolphi, 1819) and Prosorhynchus squamatus Odhner, 1905 (Digenea, Bucephalidae).

    Science.gov (United States)

    Podvyaznaya, I M; Galaktionov, K V; Irwin, S W B

    2004-08-01

    The ultrastructure of the developing excretory system of Prosorhynchoides gracilescens and Prosorhynchus squamatus cercariae is described. The development pattern was similar in both species. In early embryos the two main collecting tubes were composed of a layer of cells which were wrapped around the lumen. Later, the tubes fused and the excretory epithelium of the fusion zone and that of the lateral caudal ducts became a syncytium. The collecting tubes in the cercarial body retained their cellular organization. As the tails grew, additional excretory pores were formed in the tail stem where thickened portions of the caudal duct epithelium contacted the surface tegument. Following this, the distal portions of the lateral caudal ducts lost contact with the primary excretory pores and progressively degenerated. Excretory atrium development started with differentiation of secretory active cytons peripheral to the fusion zone. These cells gave rise to cytoplasmic extensions that penetrated the fusion zone wall to eventually form a continuous cytoplasmic layer. This layer eventually replaced some of the fusion zone excretory epithelium and became the lining of the excretory atrium. The anterior end of the fusion zone differentiated into an excretory bladder and a short posterior portion gave rise to the caudal vesicle.

  15. 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).

  16. 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.

  17. Effect of a suspension of niclosamide on cercariae of Schistosoma japonicum and prevention of infections%氯硝柳胺悬浮剂灭蚴和预防血吸虫感染的研究

    Institute of Scientific and Technical Information of China (English)

    神学慧; 戴建荣; 李叶芳; 梁幼生; 李洪军; 唐建霞; 陈祥平

    2011-01-01

    Objective To investigate the effect of a suspension of niclosamide (SN) on cercariae of Schistosoma japonicum and effective concentrations of that suspension in order to provide scientific evidence for control strategies to prevent acute schistosomiasis. Methods SN was weighed and formulated into solutions with active concentrations of niclosamide of 1×10-5, 0. 5×10-5, 1×10-6, 0.5×10-6, 1× 10-1, and 0. 5×10-7 ml/100 ml in the lab, and the effect of SN on cercariae was determined. Solutions with an active concentration of niclosamide of 1. 2× 10-5, 1. 2× 10-6, 1. 2 ×10-7, 1.2×10-8, 1.2×10-0, and 1. 2×10-10 were formulated. Cercariae were counted 0, 10 and 30 min after 200 S. japonicum cercariae were transferred to the solutions and 30 min after mice were infected with the cercariae. Forty-five days after infection, the mice were dissected and the state of infection was observed. SN with a concentration of 0. 02 g/ m2 was sprayed for 1 h on the surface of water in the field, and then the infectivity of water was determined using sentinel mice. Results All cercariae were killed after coming into contact with an active concentration of niclosamide of more than 0. 5× 10-6 for 1 min, an active concentration of niclosamide of more than 0. 5× 10-7 for 2 min, or an active concentration of niclosamide of more than 1× 10-8 for 30 min. However, all survived after coming into contact with an active concentration of niclosamide of less than 0. 5 × 10-8 for under 60 min. After the cercariae came into contact with niclosamide of 1. 2 × 10-5 for 10 or 30 min, the cercariae failed to infect mice. When the cercariae were exposed to niclosamide of 1. 2 × 10-6 for 10 min, 80% of mice were infected, and the worm burden of mice was 3. 2 worms per mouse, but 30 min later the rate of infection in mice decreased to 0. Water in the field was infective, with a rate of infection in sentinel mice of 33. 33%. After 0. 02 g/m2 SN was sprayed on the water surface for 1 h, water

  18. 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.

  19. 白头翁总皂苷对日本血吸虫虫卵毛蚴尾蚴的作用%Effect of Pulsatilla chinensis (Bunge) Regel saponins on eggs, miracidia and cercariae of Schistosoma japonicum

    Institute of Scientific and Technical Information of China (English)

    陈岩勤; 许琼明; 诸葛洪祥; 梁幼生; 李笑然; 杨世林

    2013-01-01

    目的 观察白头翁总皂苷(Pulsatilla chinensis(Bunge)Regel saponins,PRS)对日本血吸虫虫卵、毛蚴、尾蚴的杀灭效果,为白头翁总皂苷作为抗血吸虫新药提供理论和实验依据.方法 采用尾蚴腹部贴片法感染ICR小鼠,感染后42 d的鼠肝脏经研磨、过筛获得虫卵,毛蚴由虫卵孵化,尾蚴由阳性感染钉螺光照逸出,采用0、1、2、3、4、5、6、7、8 μg/ml的PRS药液分别于不同时间作用虫卵、毛蚴、尾蚴.结果 不同浓度PRS及对照药物吡喹酮(PZQ)对日本血吸虫虫卵作用24 h的孵化结果显示,PRS对虫卵孵化的抑制效果略优于PZQ,尤其在4μg/ml浓度时,日本血吸虫虫卵对PRS的作用更敏感.1、2、3、4、5、6、7、8 μg/ml的PRS药液作用于毛蚴30 min后,毛蚴死亡率分别为13.47%、26.05%、60.99%、90.84%、100%、100%、100%、100%.作用于尾蚴30 min后,尾蚴的死亡率分别为5.32%、18.81%、44.7%、76.87%、98.28%、100%、100%、100%.毛蚴、尾蚴的死亡率对PRS的作用时间和浓度有一定依赖性.结论 体外实验显示PRS对日本血吸虫虫卵、毛蚴、尾蚴均有杀伤作用,有望成为新的抗血吸虫药物.%Objective To investigate the effect of Pulsatilla chinensis (Bunge) Regel saponins (PRS) against the eggs, mira-cidia, cercariae of Schistosoma japonicum in vitro and compare its efficacy with praziquantel. Methods ICR mice were infected with the cercariae of S. japonicum by the patching abdominal method. The livers of the mice were grinded, screened, and then the eggs of S. japonicum were obtained 42 days post-infection. The miracidia were hatched by using the eggs, and the cercariae were obtained by using the infected Oncomelania snails on the light. The eggs, miracidia and cercariae of S. japonicum were incubated with 0,1,2,3,4,5,6,7,8 μg/ml PRS for different time, and praziquantel (PZQ) was used as the control. Results PRS suppressed the hatching rates of eggs for

  20. 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).

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Toxicity of lapachol and isolapachol and their potassium salts against Biomphalaria glabrata, Schistosoma mansoni cercariae, Artemia salina and Tilapia nilotica.

    Science.gov (United States)

    Lima, Nadja Maria Fernandes; dos Santos, Aldenir Feitosa; Porfírio, Zenaldo; Goulart, Marília O F; Sant'Ana, Antônio Euzébio G

    2002-07-01

    The toxicity of soluble derivatives (potassium salt) of lapachol and isolapachol in different stages of the life cycle of Schistosoma mansoni is evaluated. The potassium salts of isolapachol and lapachol showed significant molluscicidal activity against the adult snail (LC90Artemia salina Leach) indicated very high toxicity for the potassium salt of isolapachol (LC90=1.54 ppm), differently from the potassium salt of lapachol that can be considered non toxic (LC90=176.3 ppm). The same tendency is observed with piscicidal activity, for which the isolapachol salt has showed higher toxicity. The obtained selectivity ratios concerning LC50 and LC90 for lapachol, in relation to Tilapia nilotica lethality assay are 2.33 and 1.26, respectively. Despite the piscicidal toxicity, the use of the salt of lapachol can be recommended for field tests in Schistosomiasis, with caution.

  10. 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).

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 左旋咪唑防御日本血吸虫尾蚴感染的实验研究%EXPERIMENTAL STUDIES ON EFFICACY OF LEVAMISOLE IN PREVENTION FROM SCHISTOSOMA JAPONICUM CERCARIA INFECTION

    Institute of Scientific and Technical Information of China (English)

    杨明瑾; 漏磊君; 严晓岚; 吴玲娟; 李思温

    2004-01-01

    目的探讨左旋咪唑预防日本血吸虫尾蚴感染的作用.方法盐酸左旋咪唑和左旋咪唑碱口服剂量为26.25 mg/kg,分别于小鼠感染前2天口服,连服7 d;涂肤剂为1.0%、2.0%、3.0%、5.0%和7.0%,分别于感染前2、1天和当天涂肤.停药后4周解剖,检获虫体.结果盐酸左旋咪唑水溶液和左旋咪唑碱水溶液分别口服,两者的减虫率都为0;5.0%的盐酸左旋咪唑于感染当天涂肤、7.0%盐酸左旋咪唑于感染前1天涂肤,减虫率均为100.0%;2.0%、3.0%和5.0%的左旋咪唑碱于感染前1天涂药,减虫率即可达到100.0%.结论左旋咪唑涂剂能防御日本血吸虫尾蚴的感染,左旋咪唑碱效果优于盐酸左旋咪唑.口服无效.

  16. TOXICITY OF HEAVY METALS CADMIUM AND ZINC TO CERCARIA OF SCHISTOSOMA JAPONICUM%重金属镉、锌对日本血吸虫尾蚴毒性作用的观察

    Institute of Scientific and Technical Information of China (English)

    卢致民; 唐宏炜; 张进顺; 纪伟华

    2005-01-01

    目的观察重金属镉、锌单独和混合存在时对日本血吸虫尾蚴的毒性作用. 方法分别将40~50个尾蚴置于不同浓度(100、10、1、0.1 mg/L)的镉、锌、镉/锌混合溶液中,20~25℃温箱培养,每隔30 min解剖显微镜下观察尾蚴形态变化与存活数量. 结果尾蚴暴露于浓度为10、100 mg/L的镉、锌、镉/锌混合物溶液后,在相同观察时间内,尾蚴断尾率、死亡率显著高于对照组(P<0.01或P<0.05);尾蚴断尾率、死亡率随镉、锌、镉/锌混合溶液浓度升高而升高,以100 mg/L的镉/锌混合溶液毒性作用最强. 结论重金属镉、锌无论是单独存在还是混合存在,对日本血吸虫尾蚴都有一定的毒性作用,并且浓度越高,毒性作用越强.

  17. Preliminary Study on the Ecology of Trichobilharzia Cercariae in the Huaihe River System%淮河水系毛毕吸虫尾蚴生态的初步研究

    Institute of Scientific and Technical Information of China (English)

    盛似春; 秦志辉; 张明群; 邰燕; 倪仕钢; 文继月

    2004-01-01

    目的了解淮河水系毛毕吸虫尾蚴的生态习性及特征.方法2002年6月至2003年5月,在安徽省淮南市郊淮河水系支流窑河渔场,逐月采集耳萝卜螺压片镜检,用感染毛毕吸虫的阳性螺逸尾蚴,滴瓶遮光法收集尾蚴.用不同时龄尾蚴感染雏鸭,以三角烧瓶顶管法孵化毛蚴检测雏鸭感染率.结果螺体内尾蚴检出率呈明显的季节消长,尾蚴检出率7月份为0.81%,6月为0.65%,4~5月和8~10月均为0.07%~0.26%,逐月差异具有极显著性意义(P<0.01).尾蚴逸出数量呈明显的日周期变化,每天上午8:00~12:00为逸蚴高峰期,温度和光照影响显著.尾蚴具有强烈的趋光性,自然变温(18~25℃)下最长寿命为52 h,半数死亡时间为41 h.对雏鸭感染力与尾蚴时龄关系密切,30 min~8 h时龄感染力最强,40 h以后感染力丧失.结论初步探明淮河水系毛毕吸虫尾蚴的生态习性及特征.

  18. Larval stages of digenetic trematodes in Melanopsis praemorsa snails from freshwater bodies in Palestine

    Institute of Scientific and Technical Information of China (English)

    Sami Bdir; Ghaleb Adwan

    2011-01-01

    Objective: To detect the species of larval trematodes (cercariae) in Melanopsis praemorsa snails from 5 different fresh water bodies in Palestine. Methods: A total of 1 880 Melanopsis praemorsa snails were collected from different fresh water bodies in Palestine from October, 2008 to November, 2010. Cercariae in Melanopsis praemorsa snails were obtained by lighting and crushing methods. The behavior of cercariae was observed using a dissecting microscope. Results: Three different species of larval trematodes were identified from Melanopsis praemorsa snails collected only from Al-Bathan fresh water body, while snails from other water bodies were not infected. These species were microcercous cercaria, xiphidiocercaria and brevifurcate lophocercous cercaria. These cercariae called Cercaria melanopsi palestinia I, Cercaria melanopsi palestinia II and Cercaria melanopsi palestinia III have not been described before from this snail in Palestine. The infection rate of Melanopsis praemorsa collected from Al-Bathan fresh water body was 5.7%, while the overall infection rate of snails collected from all fresh water bodies was 4.3%. Details are presented on the morphology and behavior of the cercariae as well as their development within the snail. Conclusions: These results have been recorded for the first time and these cercariae may be of medical and veterinary importance.

  19. Larval stages of Neoplagioporus elongatus (Goto and Ozaki, 1930) (Opecoelidae: Plagioporinae), with notes on potential second intermediate hosts.

    Science.gov (United States)

    Yano, Ayaka; Urabe, Misako

    2017-04-01

    The morphology of sporocysts and cercariae of Neoplagioporus elongatus (Goto and Ozaki, 1930) is described for the first time. A cotylomicrocercous cercaria obtained from the sorbeoconch snail Semisulcospira nakasekoae was confirmed to be the cercaria of N. elongatus, based on the degree of sequence identity of the COI gene to that of adult worms. Freshwater annelids (oligochaetes and leeches) and some aquatic insects (odonates) were demonstrated experimentally to be potential second intermediate hosts.

  20. The cercarial glycocalyx of Schistosoma mansoni

    OpenAIRE

    1985-01-01

    Cercariae, the freshwater stage of Schistosoma mansoni infectious to man, are covered by a single unit membrane and an immunogenic glycocalyx. When cercariae penetrate the host skin, they transform to schistosomula by shedding tails, secreting mucous and enzymes, and forming microvilli over their surface. Here the loss of the glycocalyx from cercariae transforming in vitro was studied morphologically and biochemically. By scanning electron microscopy, the glycocalyx was a dense mesh composed ...

  1. [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.

  2. 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.

  3. The toxicity of bacillus thuringiensis crystal toxin to cercaria of Schistosoma japonicum cultured in vivo%苏云金芽孢杆菌晶体蛋白对钉螺体内日本血吸虫幼虫的作用

    Institute of Scientific and Technical Information of China (English)

    熊波; 付财; 姚宝安

    2003-01-01

    将不同菌株、不同浓度的苏云金芽孢杆菌伴胞晶体蛋白作用于钉螺体内的日本血吸虫幼虫阶段,经24h和48h后,通过显微镜观察,结果发现4种苏云金芽孢杆菌伴胞晶体蛋白均对钉螺体内血吸虫幼虫有毒杀作用,其中Bt-02的毒杀作用最强.

  4. 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.

  5. 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.

  6. Toxicity of chlorophyllin in different wavelengths of visible light against Fasciola gigantica larvae.

    Science.gov (United States)

    Singh, Divya Jyoti; Singh, D K

    2015-03-01

    Toxicity of chlorophyllin against redia and cercaria larvae of Fasciola gigantica was studied under irradiation of visible light. Highest and lowest toxicity of chlorophyllin against both larvae was noted under red (redia - 8 h LC₅₀ 7.88 mg/10 mL and cercaria - 11.99 mg/10 mL) and green (redia - 8 h LC₅₀ 32.12 mg/10 mL and cercaria - 8 h LC₅₀ 43.80 mg/10 mL) light irradiation respectively. The highest toxicity of chlorophyllin under red light irradiation against redia (8h LC₅₀ 7.88 mg/10 mL)/cercaria (8h LC₅₀ 11.99 mg/10 mL) was followed by white (8 h LC₅₀ redia - 20.48 mg/10 mL, 8 h LC₅₀ cercaria - 18.0 3mg/10 mL), blue (8 h LC₅₀ redia - 33.10 mg/10 mL/ 8 h LC₅₀ cercaria - 19.98 mg/10 mL) and yellow (8 h LC₅₀ redia - 23.87 mg/10 mL/ 8 h LC₅₀ cercaria - 23.48 mg/10 mL). Chlorophyllin treatment in darkness (control I) and without treatment of chlorophyllin, while all other conditions were same as treatment group (control II) caused no mortality of redia/cercaria larva. Chlorophyllin might be a promising new safe strategy to replace synthetic larvicide in fasciolosis control programme.

  7. Morphological and molecular studies on life cycle stages of Diphtherostomum brusinae (Digenea: Zoogonidae) from northern Portugal.

    Science.gov (United States)

    Pina, S; Tajdari, J; Russell-Pinto, F; Rodrigues, P

    2009-12-01

    Diphtherostomum brusinae was first recorded by the present study in the north of Portugal. Sporocysts, containing cercariae and encysted metacercariae, were observed in the gonads and digestive gland of the gastropod Nassarius reticulatus. Metacercariae were also found infecting the foot, mantle border and gills of the cockle Cerastoderma edule. The adult form was lodged in the rectum of the definitive host Diplodus sargus. The morphology of the three parasitic stages was studied by light (LM) and scanning electron microscopy (SEM). Despite the close similarity between cercaria and metacercaria, SEM data provided information that allowed their differentiation, namely the presence of a dense crown of microvilli around the oral cavity of the cercariae, which was absent in the metacercariae. In addition, the metacercariae presented a specific pre-acetabular rectangular band with conspicuous triangular spines. The adult showed characteristics of D. brusinae species, in particular the presence of acetabular lips, compact vitellaria and large elliptical eggs. Sequenced ITS1 data clearly demonstrated that the cercariae and metacercarial cysts from N. reticulatus, the cysts from C. edule and the adult isolated from D. sargus were life cycle stages that belonged to the same species, i.e. D. brusinae. Two transmission strategies in the life cycle of this species were observed: (1) cercariae encyst within the sporocysts of N. reticulatus and await ingestion by the definitive host; and (2) N. reticulatus naturally emits cercariae; they encyst in C. edule or the environment and are ingested by the definitive host.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

    Science.gov (United States)

    Rowel, Candia; Fred, Besigye; Sousa-Figueiredo, Jose C.; Kabatereine, Narcis B.; Stothard, J. Russell

    2015-01-01

    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. PMID:25705680

  13. 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.

  14. [Demonstration of the existence of a marine cycle in the strigeides: Cardiocephalus longicollis Szidat, 1928 (Trematoda: Strigeidae)].

    Science.gov (United States)

    Prevot, G; Bartoli, P

    1980-01-01

    During their investigations on parasitism of fishes and birds in the lagoon of Brusc (Var), the authors have discovered the life cycle of Cardiocephalus longicollis. Cercariae of pharyngeate furcocercous type develop in sporocysts in the digestive gland of the marine prosobranch Nassa corniculum. The cercaria is identified as Cercaria nassae (Dolgikh, 1965) from Nassa reticulata in Black sea; it closely resembles Cercaria nassa (Martin, 1945) from Ilyanassa obsolseta (syn. Nassa obsoleta) at Woods Hole (U.S.A.). Several intermediate hosts have been related; they are the marine fishes Diplodus annularis, D. vulgaris, Boops salpa, Pagellus mormyrus (Sparidae) and Belone belone (Scombresocidae). Metacercariae of tetracotyle type were found in the cavity of optical lobes of the brain. Experimental contamination of fishes: Potamoschistus microps, Blennius sp., Mugil cephalus and Syngnathus abaster has been negative; that of Diplodus annularis and D. sargus, positive. It allowed to follow the development from cercaria to tetracotyle. In Provence natural definitive hosts are Larus argentatus and L. ribidundus; contaminations of these birds with metacercariae experimentally raised in Diplodus annularis and D. vulgaris were successfull. Some observations are pointed out especially the development of the parasite in the definitive host, the organisation of tribocytic organ and the geographical distribution of the parasite.

  15. Schistosoma mansoni: quantification of skin penetration and early migration by differential external radioassay and autoradiography

    Energy Technology Data Exchange (ETDEWEB)

    Georgi, J.R. (New York State College of Veterinary Medicine, Ithaca (USA))

    1982-04-01

    Eleven gamma-emitting radionuclides (/sup 49/Sc, /sup 54/Mn, /sup 59/Fe, /sup 60/Co, /sup 65/Zn, /sup 75/Se (as selenomethionine, selenocystine, selenite and selenate), /sup 109/Cd, /sup 125/Sb, /sup 133/Ba, /sup 137/Cs and /sup 203/Hg) were screened as labelling agents for Schistosoma mansoni cercariae by incubation of infected Biomphalaria glabrata snails in radioactive solution. Only (/sup 75/Se)methionine yielded satisfactorily labelled cercariae. Differential external radioassay, a new technique employing partial body shielding within a total body counter, permitted separate estimation of tail and body radioactivity of conscious mice previously exposed by tail immersion to /sup 75/Se-labelled cercariae, with measurements repeated as often as desired. Approximately 39% of the /sup 75/Se present in emergent cercariae was retained by schistosomula transformed in vitro but this was subject to considerable variation, especially in schistosomula transformed in vivo. Secreted or catabolized label from penetrant cercariae and schistosomula was rapidly removed from the skin by the bloodstream. Numbers of schistosomula in tail skin were directly proportional to the number of reduced silver foci counted on tail autoradiograms; only a very small fraction of tail radioactivity represented unbound ('spurious') label. Migration of schistosomula away from skin was 50% complete at 3.8-4.3 days, as determined by probit analysis of autoradiographic data.

  16. 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

    2016-10-14

    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.

  17. Larval trematodes in freshwater molluscs from the Elbe to Danube rivers (Southeast Germany): before and today.

    Science.gov (United States)

    Faltýnková, Anna; Haas, Wilfried

    2006-10-01

    Studies on life cycles of trematodes have a long tradition in Germany; (Odening 1978) listed a total of 177 trematodes, which can potentially complete their life cycles in German inland waters. However, almost no recent data on the occurrence of larval stages in molluscs are available. Therefore, a survey of trematodes in Southeast Germany was carried out in 2004. A total of 31 species of ten families (29 species of cercariae, seven species of metacercariae, and five species found of both) were found in 311 (4.9%) molluscs of 15 species. The dominant cercariae were Plagiorchis elegans, Echinoparyphium aconiatum, Opisthioglyphe ranae, and Diplostomum pseudospathaceum. Echinoparyphium pseudorecurvatum is reported, for the first time, under its valid scientific name from Germany. In previous studies from the same region, 88 species of cercariae of 16 families were found in 19 species of molluscs (52 cercariae with valid names and 36 not identified to species level). It is proposed that there is still a very similar spectrum of the most common species of cercariae typical for Central Europe as found 20, but also 100-150 years ago.

  18. 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.

  19. 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.

  20. Characterization of the Life Cycle of a Fish Eye Fluke, Austrodiplostomum ostrowskiae (Digenea: Diplostomidae), with Notes on Two Other Diplostomids Infecting Biomphalaria havanensis (Mollusca: Planorbidae) from Catfish Aquaculture Ponds in Mississippi, USA.

    Science.gov (United States)

    Rosser, Thomas G; Alberson, Neely R; Khoo, Lester H; Woodyard, Ethan T; Pote, Linda M; Griffin, Matt J

    2016-04-01

    Ocular diplostomiasis is caused by trematode species in the family Diplostomidae, specifically those in the genera Austrodiplostomum, Diplostomum, and Tylodelphys. Diplostomid trematodes are globally distributed parasites of fish. Heavy infections of diplostomids that parasitize the eyes of fish can result in acute mortality while chronic infections are often characterized by impaired vision or blindness. In the southeastern United States, commercial catfish production is threatened by piscivorous birds and the many trematode species that parasitize them. The life cycles typically involve a piscivorous avian definitive host, a mollusk first intermediate host, and a fish second intermediate host. A survey of parasites infecting the snail host Biomphalaria havanensis (= B. obstructa ) in catfish production ponds was undertaken. Snails were collected from 2 separate ponds during the summer of 2014 and observed for the release of trematode cercariae. A total of 1,740 snails were collected. Three distinct longifurcate pharyngeate cercariae were observed and these cercariae were characterized morphologically and molecularly. Sequencing of ∼4,200 base pairs (bp) of the nuclear ribosomal genes and ∼450 bp of the mitochondrial cytochrome c oxidase gene revealed 3 genetically distinct species. One morphotype shared 99-100% sequence identity with metacercariae from the aqueous and vitreous humors of gizzard shad Dorosoma cepedianum and channel catfish Ictalurus punctatus as well as an adult trematode, Austrodiplostomum ostrowskiae, a parasite of the double-crested cormorant Nannopterum auritus. The remaining 2 cercariae morphotypes shared 99-100% sequence identity with an unidentified Tylodelphys sp. and Austrodiplostomum sp. metacercaria from the brain and eyes of several freshwater fish. Herein we molecularly link the cercaria, metacercaria, and adult stage of the life cycle of A. ostrowskiae, identifying the snail host for this parasite, in addition to providing notes

  1. Toxicity of anti-fouling biocides to Parorchis acanthus (Digenea: Philophthalmidae) cercarial encystment.

    Science.gov (United States)

    Morley, N J; Leung, K M Y; Morritt, D; Crane, M

    2003-03-17

    The toxicity of the anti-fouling biocides tributyltin (TBTO), copper, and Irgarol 1051 (irgarol) at nominal concentrations ranging from 10 to 10,000 microg l(-1) was investigated against the speed of encystment and successful formation of a protective cyst of the cercariae of Parorchis acanthus. For all biocide exposures, cercariae had a much slower rate of encystment and reduced cyst formation than controls. Exposure of the snail host Nucella lapillus for 7 d caused complete cessation of cercarial shedding in irgarol-exposed snails but had no effect on cercarial encystment from TBTO and copper-exposed snails. The mechanisms of toxicity of the biocides are briefly discussed.

  2. Synthesis and cercaricidal activities of a serial of novel self-diffused cercaricides derived from niphensamide

    Institute of Scientific and Technical Information of China (English)

    Wei Guo; Lv Yin Zheng; Yong Quan Wu; Xiao Lin Fan

    2008-01-01

    A serial of novel cercaricides that can self-diffuse on the water surface were designed and synthesized according to the special habit of cercariae larvae.These compounds were derived from niphensamide.While the compounds were dropped on the surface of water,the liquor diffused along the air-water interface and formed thin membranes floating on the water surface immediately.The strong cercaricidal activities against the cercariae larvae of Schistosome japonicum of these compounds have been revealed by further experiments.

  3. Sequential histological changes in Biomphalaria glabrata during the course of Schistosoma mansoni infection

    Directory of Open Access Journals (Sweden)

    Queli Teixeira Lemos

    2001-07-01

    Full Text Available Biomphalaria glabrata, highly susceptible to Schistosoma mansoni, were seen to shed less and less cercariae along the time of infection. Histological examination kept a close correlation with this changing pattern of cercarial shedding, turning an initial picture of no-reaction (tolerance gradually into one of hemocyte proliferation with formation of focal encapsulating lesions around disintegrating sporocysts and cercariae, a change that became disseminated toward the 142nd day post miracidial exposure. Findings were suggestive of a gradual installation of acquired immunity in snails infected with S. mansoni.

  4. Cercarial production from Biomphalaria alexandrina infected with Schistosoma mansoni.

    Science.gov (United States)

    Chu, K Y; Dawood, I K

    1970-01-01

    The present paper deals with longitudinal and cross-sectional methods of counting cercariae shed from Biomphalaria alexandrina in Egypt, both experimentally and naturally infected with schistosomes. By the longitudinal method, the daily output of cercariae was counted from the first shedding from experimentally infected snails and from the day of collection from naturally infected ones. The results show that the size of the snails at the time of shedding exerts a very large effect on the output of cercariae and that the numbers obtained in the laboratory are not representative of cercarial output in the field. By the cross-sectional method, the cercarial output in the first 24 hours from infected snails collected in different months from the field was counted. The results show that output is size-specific. When the size-specific output is adjusted to the size-composition of infected snails taken from the field, it is estimated that the daily output from infected snails in the field may be 957.7 cercariae. However, this number may vary with the season.

  5. Ultrastructural and biochemical detection of biotin and biotinylated polypeptides in Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Santos P.R.P.

    1997-01-01

    Full Text Available Biotinylation is proposed for the identification of surface proteins in Schistosoma mansoni using the streptavidin-HRP conjugate for the detection of labeled polypeptides. However, control samples also showed several endogenous biotinylated polypeptides. In an attempt to determine the possibility of nonspecific binding between the streptavidin-HRP conjugate and polypeptides from S. mansoni, the conjugate was blocked with biotinamidecaproate-N-hydroxysuccinimide ester (BcapNHS before biotin-streptavidin blotting. No bands were detected on the nitrocellulose sheet, demonstrating the specific recognition of biotin by the streptavidin present in the conjugate. Whole cercariae and cercarial bodies and tails showed several endogenous biotinylated polypeptides. The biotin concentration was 13 µg/190,000 cercariae. Adult worms presented less endogenous biotinylated polypeptides than cercariae. These results may be due to changes in the environment from aerobic to anaerobic conditions when cercarial bodies (schistosomula are transformed into adult worms and a decrease in CO2 production may occur. Cercariae, cercarial bodies and adult male worms were examined by transmission electron microscopy employing an avidin-colloidal gold conjugate for the detection of endogenous biotin. Gold particles were distributed mainly on the muscle fibers, but dispersed granules were observed in the tegument, mitochondria and cytosol. The discovery of endogenous biotin in S. mansoni should be investigated in order to clarify the function of this vitamin in the parasite

  6. Protective Effect of Chronic Schistosomiasis in Baboons Coinfected with Schistosoma mansoni and Plasmodium knowlesi

    DEFF Research Database (Denmark)

    Nyakundi, Ruth K; Nyamongo, Onkoba; Maamun, Jeneby;

    2016-01-01

    cercariae. At 14 and 15 weeks postinfection, one group was given praziquantel to treat schistosomiasis infection. Four weeks later, the two groups plus a new malaria control group (n = 8) were intravenously inoculated with 10(5) Plasmodium knowlesi parasites and monitored daily for development of severe...

  7. Treatment Effects and Integrated Morbidity Control of Schistosomiasis

    NARCIS (Netherlands)

    D. Danso-Appiah (Anthony)

    2009-01-01

    textabstractSchistosomiasis is caused by the blood fl uke and leads to signifi cant ill-health and economic burden. The disease is common in the tropics and subtropics and acquired through contact with freshwater bodies infested with the infective cercariae shed from the intermediate host snail. Fro

  8. 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.

  9. 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.

  10. 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

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    Divya Jyoti SINGH

    2016-01-01

    Full Text Available 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.

  13. 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 Lymnaeidae, 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.

  14. Induction of Protective Immune Responses against Schistosomiasis Haematobium in Hamsters and Mice Using Cysteine Peptidase-Based Vaccine

    Directory of Open Access Journals (Sweden)

    Hatem A M Tallima

    2015-03-01

    Full Text Available One of the major lessons we learned from the radiation-attenuated cercariae (RA vaccine studies is that protective immunity against schistosomiasis is dependent on the induction of T helper (Th1/Th2-related immune responses. Since most schistosome larval and adult-worm-derived molecules used for vaccination uniformly induce a polarized Th1 response, it was essential to include a type 2 immune responses-inducing molecule, such as cysteine peptidases, in the vaccine formula. Here we demonstrate that a single subcutaneous injection of Syrian hamsters with 200 microg active papain 1 h before percutaneous exposure to 150 cercariae of Schistosoma haematobium led to highly significant (P 50% in worm burden and worm egg counts in intestine. Immunization of hamsters with 20 microg recombinant glyceraldehyde 3-phosphate dehydrogenase (rSG3PDH and 20 ug 2-cys peroxiredoxin-derived peptide in a multiple antigen peptide construct (PRX MAP together with papain (20 microg/hamster as adjuvant led to considerable (64% protection against challenge S. haematobium infection, similar to the levels reported with irradiated cercariae. Cysteine peptidases-based vaccination was also effective in protecting outbred mice against a percutaneous challenge infection with S. haematobium cercariae. In two experiments, a mixture of Schistosoma mansoni cathepsin B1 (SmCB1 and Fasciola hepatica cathepsin L1 (FhCL1 led to highly significant (P < 0.005 reduction of 70% in challenge S. haematobium worm burden and 60% reduction in liver egg counts. Mice vaccinated with SmCB1/FhCL1/ rSG3PDH mixture and challenged with S. haematobium cercariae three weeks after the second immunization displayed highly significant (P < 0.005 reduction of 72% in challenge worm burden and no eggs in liver of 8-10 mice/group, as compared to unimmunized mice, associated with production of a mixture of type 1 and type 2-related cytokines and antibody responses.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Mintsa-Nguéma Rodrigue

    2014-01-01

    Full Text Available 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.

  17. [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).

  18. Schistosoma japonicum: An ultraviolet-attenuated cercarial vaccine applicable in the field for water buffaloes

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Y.E.; Jiang, C.F.; Han, J.J.; Li, Y.L.; Ruppel, A. (Tongii Medical Univ., Wuhan, Hubei Province (China))

    1990-07-01

    Water buffaloes were vaccinated three times with 10,000 Schistosoma japonicum cercariae irradiated with ultraviolet (uv) light at a dose of 400 microW x min/cm2. The irradiation was performed with cheap, simple, and portable equipment in a rural area of Hubei Province (People's Republic of China). A challenge infection of 1000 untreated cercariae was given to six vaccinated and six naive control buffaloes, while two vaccinated animals were not challenged. The experiment was terminated 6 weeks after the challenge. Control animals had lost body weight and harbored a mean of 110 worms and 37 eggs per gram of liver. The vaccinated animals gained weight after the challenge and developed 89% resistance to infection with S. japonicum. Since schistosomiasis japonica is nowadays transmitted in China predominantly by domestic livestock, a uv-attenuated cercarial vaccine for bovines may contribute to the control of this disease.

  19. 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.

  20. 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.

  1. Susceptibility of Iraqi fresh water snails to infection with Schistosoma haematobium and Schistosoma mansoni Egyptian strains.

    Science.gov (United States)

    Wajdi, N A; Hussain, W I; El-Hawary, M F

    1979-01-01

    A great number of Egyptian workers and farmers are seeking settlement in Iraq and some of them proved to have either Schistosoma Haematobium (S.h.) or Schistosoma mansoni (S.m) or even mixed infection. Besides, there is the possibility that some of the Iraqi fresh water snails may prove to be susceptible to infection by one or both of the Schistosoma Egyptian strains. The present study deals with investigations on the susceptibility of Iraqi B. truncatus, Gyranaulus ehrenbergi, Physa c.f. fontinalis, Lymnea lagetis, Melanoides tuberculata and Melanopsis nodes by these parasites. Egyptian S. haematobium but not Egyptian S. mansoni infect Iraqi B. truncatus and both proved to be unable to infect any of the other snails included in the study. Yet, the number of cercariae shedded by B. truncatus snails infected with the Egyptian S. haematobium strain, was much less that the number of cercariae shedded by these snails when infected with the Iraqi S. Haematobium strain.

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

    OpenAIRE

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

    2006-01-01

    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 4...

  3. A strategy for emergency treatment of Schistosoma japonicum-infested water

    Directory of Open Access Journals (Sweden)

    Li Hong-Jun

    2011-11-01

    Full Text Available Abstract Background Schistosomiasis japonica, caused by contact with Schistosoma japonicum cercaria-infested water when washing, bathing or production, remains a major public-health concern in China. The purpose of the present study was to investigate the effect of a suspension concentrate of niclosamide (SCN on killing cercaria of S. japonicum that float on the water surface, and its toxicity to fish, so as to establish an emergency-treatment intervention for rapidly killing cercaria and eliminating water infectivity. Results At 30 min after spraying 100 mg/L SCN, with niclosamide dosages of 0.01, 0.02, 0.03, 0.04 g/m2, the water infectivity reduced significantly and no infectivity was found at 60 min after spraying SCN. The surface of static water was sprayed with 100 mg/L SCN, the peak concentration was found at 0 min, and the solution diffused to site with a water depth of 10 cm after 10 min. 30 min later, SCN diffused to the whole water body, and distributed evenly. After spraying 100 mg/L SCN onto the surface of the water with a volume of(3.14 × 202×50cm3, with niclosamide dosages of 0.02 g/m2, 96 h later, no death of zebra fish was observed. Conclusions By spraying 100 mg/L SCN, with a niclosamide dosage of 0.02 g/m2 onto the surface of S. japonicum-infested water, infectivity of the water can be eliminated after 30-60 min, and there is no evident toxicity to fish. This cercaria-killing method, as an emergency-treatment intervention for infested water, can be applied in those forecasting and early warning systems for schistosomiasis.

  4. 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.

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

    OpenAIRE

    JR Kusel; FA Oliveira; Todd, M; F Ronketti; SF Lima; ACA Mattos; KT Reis; PMZ Coelho; JA Thornhill; Ribeiro, F.

    2006-01-01

    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 prel...

  6. 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.

  7. Fluorescent imaging of antigen released by a skin-invading helminth reveals differential uptake and activation profiles by antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    Ross A Paveley

    Full Text Available Infection of the mammalian host by the parasitic helminth Schistosoma mansoni is accompanied by the release of excretory/secretory molecules (ES from cercariae which aid penetration of the skin. These ES molecules are potent stimulants of innate immune cells leading to activation of acquired immunity. At present however, it is not known which cells take up parasite antigen, nor its intracellular fate. Here, we develop a technique to label live infectious cercariae which permits the imaging of released antigens into macrophages (MPhi and dendritic cells (DCs both in vitro and in vivo. The amine reactive tracer CFDA-SE was used to efficiently label the acetabular gland contents of cercariae which are released upon skin penetration. These ES products, termed '0-3hRP', were phagocytosed by MHC-II(+ cells in a Ca(+ and actin-dependent manner. Imaging of a labelled cercaria as it penetrates the host skin over 2 hours reveals the progressive release of ES material. Recovery of cells from the skin shows that CFDA-SE labelled ES was initially (3 hrs taken up by Gr1(+MHC-II(- neutrophils, followed (24 hrs by skin-derived F4/80(+MHC-II(lo MPhi and CD11c(+ MHC-II(hi DC. Subsequently (48 hrs, MPhi and DC positive for CFDA-SE were detected in the skin-draining lymph nodes reflecting the time taken for antigen-laden cells to reach sites of immune priming. Comparison of in vitro-derived MPhi and DC revealed that MPhi were slower to process 0-3hRP, released higher quantities of IL-10, and expressed a greater quantity of arginase-1 transcript. Combined, our observations on differential uptake of cercarial ES by MPhi and DC suggest the development of a dynamic but ultimately balanced response that can be potentially pushed towards immune priming (via DC or immune regulation (via MPhi.

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

    OpenAIRE

    Divya Jyoti SINGH; 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. Toxi...

  9. Ultrastructural study on the morphological changes to male worms of Schistosoma mansoni after in vitro exposure to allicin Estudo ultraestrutural das alterações morfológicas de vermes machos de Schistosoma mansoni após exposição in vitro à alicina

    OpenAIRE

    Caliandra Maria Bezerra Luna Lima; Francisca Inês de Sousa Freitas; Liana Clébia Soares Lima de Morais; Marília Gabriela dos Santos Cavalcanti; Lânia Ferreira da Silva; Rafael José Ribeiro Padilha; Constância Gayoso Simões Barbosa; Fábio André Brayner dos Santos; Luiz Carlos Alves; Margareth de Fátima Formiga Melo Diniz

    2011-01-01

    INTRODUCTION: Garlic has a wide range of actions, including antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic actions. This antiparasitic activity has been attributed to allicin, which is the main constituent of garlic. The present study aimed to investigate the in vitro activity of allicin on the tegument of adult Schistosoma mansoni worms using scanning electron microscopy. METHODS: Swiss Webster mice were infected with S. mansoni cercariae (100 per mouse) and sacrificed ...

  10. 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

  11. Molecular investigation of Neorickettsia risticii in trematodes and snails in a region with serological evidence of this agent in horses, state of Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    R.L. Costa

    Full Text Available ABSTRACT In Brazil, some studies have indicated that Neorickettsia risticii circulates in horses, but it is unclear which are the possible intermediate vectors of this bacterium in the country. The aim of this study was to use molecular techniques in order to analyze the presence of N. risticii in snails and larval stages of trematodes in farms in a region with a history of seroreactive horses towards this bacterium, in Rio de Janeiro, Brazil. Convenience sampling was used in the studied region. The collected snails were exposed to incandescent light (60W for 2-4 hours in order to investigate trematodes in larval forms. Deoxyribonucleic acid (DNA was extracted from snail tissue and trematode. Real-time PCR (qPCR technique was used to investigate the presence of a 16S rRNA gene fragment of N. risticii. Snail specimens (n=410 were collected from 11 horse-breeding farms, and the following species were identified: Melanoides tuberculata, Pomacea sp., Biomphalaria tenagophila, Physa acuta, Drepanotrema anatinum and Biomphalaria straminea. Only 3.17% (n=13/410 of the collected snails were infected by trematodes. The cercariae obtained from these snails were classified as Megalourous cercariae, Pleurolophocercus cercariae and Furcocercous cercariae. There was no amplification of the target DNA of N. risticii in the snail and trematode samples tested by qPCR. Based on these data, the transmission of N. risticii by trematodes using these snail species in this region does not appear to occur or occurs at very low rates. Thus, further studies are needed in order to clarify which species of invertebrate hosts are infected by this bacterium and potentially participate in the transmission chain of equine neorickettsiosis in the state of Rio de Janeiro, Brazil.

  12. Snails and trematode infection after Indian Ocean tsunami in Phang-Nga Province, southern Thailand.

    Science.gov (United States)

    Sri-Aroon, Pusadee; Chusongsang, Phiraphol; Chusongsang, Yupa; Pornpimol, Surinthwong; Butraporn, Piyarat; Lohachit, Chantima

    2010-01-01

    The tsunami and non-tsunami affected areas of Takua Pa District, Phang-Nga Province were investigated for fresh- and brackish-water snails that transmit human parasitic diseases during 2006 and 2007. Among 46 snail species found, 17 species of 8 families were freshwater snails, 28 species of another 7 families were brackish-water snails, and 1 species was a land snail. Of these species, 11 freshwater snails, 4 brackish-water snails and 1 land snail were of medical importance. The fresh-water snails were Pomacea canaliculata, Pila angelica, P. gracilis, P. polita, Filopaludina (S.) martensi, F. (F.) s. polygramma, Melanoides tuberculata, Indoplanorbis exuxtus, Radix rubiginosa, Helicorbis umbilicalis, Gyraulus convexiusculus. Four brackish-water snails were Cerithidea cingulata, C. djadjarensis, C. alata, Sermyla riqueti and Achatina fulica was the land snail. I. exutus, M. tuberculata and F. (F.) s. polygramma harbored Xiphidio, Microcercus, Furocercus, Echinostome cercariae, and cercaria without eyespots or tail with hair. Three species of brackish-water snails, Cerithidia cingulata, C. djadjariensis, and C. alata presented with 6 types of trematode cercariae and rediae. Knowledge of medically important snails and their parasitic diseases, and prevention were given to Takua Pa people by poster, pamphlets and broadcasting through community radio.

  13. Seasonal transmission of Opisthorchis viverrini sensu lato and a lecithodendriid trematode species in Bithynia siamensis goniomphalos snails in northeast Thailand.

    Science.gov (United States)

    Namsanor, Jutamas; Sithithaworn, Paiboon; Kopolrat, Kulthida; Kiatsopit, Nadda; Pitaksakulrat, Opal; Tesana, Smarn; Andrews, Ross H; Petney, Trevor N

    2015-07-01

    Seasonal changes play roles in the transmission success of fish-borne zoonotic trematodes (FZT). This study examined the seasonal transmission patterns of Opisthorchis viverrini sensu lato (s.l.) and a virgulate cercaria (family Lecithodendriidae) in the snail intermediate host, Bithynia siamensis goniomphalos in northeast Thailand. Snail samples were collected monthly during the rainy, cool, and hot seasons during 2012-2013 to determine the prevalence and intensity of larval trematode infections. The prevalence of O. viverrini s.l. varied significantly with season, being 0.31%, 1.05%, and 0.37% in the rainy, cool, and hot seasons, respectively (P < 0.05). Similarly, the prevalence of virgulate cercariae was 3.11%, 6.80%, and 1.64% in the rainy, cool, and hot seasons, respectively (P < 0.05). The intensity of larval trematode infections also varied between seasons and peaked in the hot season (P < 0.05) in both species. The snails infected with O. viverrini s.l. were significantly smaller (P < 0.05) and those infected with virgulate cercariae were significantly larger (P < 0.05) than uninfected snails. Seasonal variation and the different sizes of B. s. goniomphalos parasitized by O. viverrini s.l. and virgulate trematodes indicate complex host-parasite interactions with important implications for the epidemiology of O. viverrini s.l.

  14. 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.

  15. Molecular identification of Austrobilharzia species parasitizing Cerithidea cingulata (Gastropoda: Potamididae) from Kuwait Bay.

    Science.gov (United States)

    Al-Kandari, W Y; Al-Bustan, S A; Isaac, A M; George, B A; Chandy, B S

    2012-12-01

    Avian schistosomes belonging to the genus Austrobilharzia (Digenea: Schistosomatidae) are among the causative agents of cercarial dermatitis in humans. In this paper, ribosomal and mitochondrial DNA sequences were used to study schistosome cercariae from Kuwait Bay that have been identified morphologically as Austrobilharzia sp. Sequence comparison of the ribosomal DNA (rDNA) 28S and 18S regions of the collected schistosome cercariae with corresponding sequences of other schistosomes in GenBank revealed high sequence similarity. This confirmed the morphological identification of schistosome cercariae from Kuwait Bay as belonging to the genus Austrobilharzia. The finding was further supported by the phylogenetic tree that was constructed based on the combined data set 18S-28S-mitochondrial cytochrome oxidase I (mtCO1) sequences in which Austrobilharzia sp. clustered with A. terrigalensis and A. variglandis. Sequence comparison of the Austrobilharzia sp. from Kuwait Bay with A. variglandis and A. terrigalensis based on mtCO1 showed a variation of 10% and 11%, respectively. Since the sequence variation in the mtCO1 was within the interspecific range among trematodes, it seems that the Austrobilharzia species from Kuwait Bay is different from the two species reported in GenBank, A. terrigalensis and A. variglandis.

  16. 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.

  17. The life cycle of Monorchis parvus (Digenea: Monorchiidae) demonstrated by developmental and molecular data.

    Science.gov (United States)

    Bartoli, P; Jousson, O; Russell-Pinto, F

    2000-06-01

    Cercaria cerastodermae I, a digenean parasite of Cerastoderma edule, was recorded for the first time in the Atlantic Ocean off the Iberian peninsula. Sporocysts were present in the hemolymph of the digestive gland, gonad, gills, and foot of the mollusc. Most of the cercariae present within sporocysts were encysted as metacercariae. The corresponding adult stages were obtained after experimental infection of several Diplodus sargus artificially reared in fish farms and that had previously been protected against natural infections. Numerous adult specimens of Monorchis parvus were collected in Diplodus annularis along the French Mediterranean coast. Comparison of wild and experimental adults allowed the adult stage of Cercaria cerastodermae I to be identified as M. parvus. Another monorchid, Monorchis monorchis, a parasite of Spondyliosoma cantharus, was found in the same Mediterranean area and compared with M. parvus. Additionally, ITS1 nuclear ribosomal DNA sequences of C. cerastodermae I and of the adults collected in naturally infected D. annularis and S. cantharus were obtained. Sequence data indicate that C. cerastodermae I corresponds to the adult of M. parvus found in D. annularis and is clearly distinct from M. monorchis found in S. cantharus.

  18. Thermodynamics of cercarial survival and metabolism in a changing climate.

    Science.gov (United States)

    Morley, N J

    2011-09-01

    Cercariae are non-feeding free-living stages in the life cycles of trematodes, highly influenced by temperature. Their life span is brief, limited by the depletion of a non-renewable glycogen store. Warmer temperatures under the influence of climate change may promote the transmission of parasites and therefore understanding their thermobiology forms an important step in discerning the future dynamics of parasite populations. An empirical relationship exists between cercarial mean expected life span and the half-life of the population (t0·5) and therefore t0·5 is a good indicator of glycogen utilization. In this study experimental data on the effects of temperature on cercarial survival is compiled from the scientific literature and evaluated in terms of metabolism using Q10 and Arrhenius activation energy (E* or μ), common measures of temperature-mediated reaction rates. Cercariae have a variable response to temperature, which does not appear to be influenced by their life-history attributes or size. There were little differences in Q10 and E* values between most temperature ranges. In almost half the studies examined (7 of 16) cercariae demonstrated a discrete zone of thermostability over a range equivalent to typical individual mean summer temperatures. Distinct intraspecific differences in temperature responses between 3 laboratory strains of Schistosoma mansoni and 2 natural strains of Echinoparyphium recurvatum sensu stricto were apparent. The importance of these results for cercarial biology under global climate change is discussed.

  19. Schistosoma mansoni: assessment of effects of oleic acid, cercarial age and water temperature on parasite-host attraction.

    Science.gov (United States)

    Lee, Vivien S T; Burgess, Jefferey L; Sterling, Charles R; Lutz, Eric A

    2013-09-01

    Although the lifecycle of Schistosoma spp. and pathophysiology of schistosomiasis have been established, the mechanism by which cercariae find their host is not well understood. Speculatively, host infection by random and accidental host contact is not as biologically plausible as a biochemical mechanism of mammalian attraction. A few studies have indicated that biochemical cues and temperature gradients may play a role in host identification, attraction and attachment triggers. This study aimed to elucidate these mechanisms more specifically through evaluation of biochemical, age and temperature influences leading to Schistosoma mansoni cercariae attraction and attachment behaviors. Oleic acid, a common unsaturated free fatty acid in the outer layer of human skin, was tested for cercariae attraction across biologically relevant concentrations. Influence of media type (beeswax, nail varnish and agar), age-dependent behavior variability and environmentally appropriate temperatures (22 and 30 °C) were also evaluated. Results indicated that oleic acid at concentrations of 0.3, 0.9 and 1.8 g/mL in beeswax significantly increased median attachment to media (median attachment of 7.50%, 4.20% and 3.71%, respectively, P0.05). Biochemical, age and environmental factors influencing cercarial host attraction and attachment behavior have been elucidated by this study. This information will inform further development of devices for environmental surveillance and potentially improve cercarial exposure prevention strategies.

  20. Molecular Cytogenetics in Digenean Parasites: Linked and Unlinked Major and 5S rDNAs, B Chromosomes and Karyotype Diversification.

    Science.gov (United States)

    García-Souto, Daniel; Pasantes, Juan J

    2015-01-01

    Digenetic trematodes are the largest group of internal metazoan parasites, but their chromosomes are poorly studied. Although chromosome numbers and/or karyotypes are known for about 300 of the 18,000 described species, molecular cytogenetic knowledge is mostly limited to the mapping of telomeric sequences and/or of major rDNA clusters in 9 species. In this work we mapped major and 5S rDNA clusters and telomeric sequences in chromosomes of Bucephalus minimus, B. australis, Prosorhynchoides carvajali (Bucephaloidea), Monascus filiformis (Gymnophalloidea), Parorchis acanthus (Echinostomatoidea), Cryptocotyle lingua (Opisthorchioidea), Cercaria longicaudata, Monorchis parvus (Monorchioidea), Diphterostomum brusinae, and Bacciger bacciger (Microphalloidea). Whilst single major and minor rDNA clusters were mapped to different chromosome pairs in B. minimus and P. acanthus, overlapping signals were detected on a single chromosome pair in the remaining taxa. FISH experiments using major rDNA and telomeric probes clearly demonstrated the presence of highly stretched NORs in most of the digenean taxa analyzed. B chromosomes were detected in the B. bacciger samples hosted by Ruditapes decussatus. Although the cercariae specimens obtained from Donax trunculus, Tellina tenuis, and R. decussatus were in agreement with B. bacciger, their karyotypes showed striking morphological differences in agreement with the proposed assignation of these cercariae to different species of the genus Bacciger. Results are discussed in comparison with previous data on digenean chromosomes.

  1. 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.

  2. The first record of Centrocestus formosanus (Nishigori, 1924) (Digenea: Heterophyidae) in Egypt.

    Science.gov (United States)

    Yousif, F; Ayoub, M; Tadros, M; El Bardicy, S

    2016-09-01

    The life cycle of Centrocestus formosanus (Digenea: Heterophyidae) was to be successfully completed in the laboratory in the present study. Hundreds of the thiarid snail, Melanoides tuberculata, were collected from the main water course Mansouriya Canal, Giza Governorate, Egypt. The snails were individually exposed to artificial light to determine possible infection with trematode larvae. Fifteen snails were found infected with opthalmopleurolophocercous cercariae (infection index of 1.97). These opthalmopleurolophocercous cercariae shedded from snails were collected and placed in an aquarium with fish intermediate host, Gambusia affinis, to obtain metacercariae encysted in the gills. The gills with metacercariae were fed to albino rats, Rattus norvegicus, to obtain the adult worms. Adult worms were recovered in the small intestine of rats at 7 days after infection and they were identified as Centrocestus formosanus based on the morphological characteristics and the comparison with the previous descriptions in the literature. They were small, 518 × 324 μm in average size and had characteristic 32 circumoral spines around the oral sucker. The morphological characteristics of the developmental stages, from cercariae to adults, of this heterophyid fluke were given here. Therefore, the presence of this fluke is to be confirmed for the first time in Egypt by the present study.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  5. Tradeoff between establishing an infection and killing the host: response of snails ( Physa acuta) to a gradient of trematode (Halipegus eccentricus) exposures.

    Science.gov (United States)

    Gustafson, K D; Bolek, M G

    2015-02-01

    Pond snails ( Physa acuta ) were exposed to a gradient (0, 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, and 50) of trematode (Halipegus eccentricus) eggs and observed to determine egg dose effects on the survival of snails through the prepatent period, snail reproduction, and the production of cercariae. The probability of snail survival through the prepatent period significantly decreased with increasing egg exposures, where the odds of snail survival was 0.94 per trematode egg. Similarly, the probability of snail reproduction significantly decreased with increasing egg exposures, where the odds of snail reproduction was 0.85 per trematode egg. In contrast, the probability of a snail shedding cercariae significantly increased with increasing egg exposures, where the odds of reaching a patent infection were 1.64 per trematode egg. However, snails shedding cercariae that were exposed to higher doses of trematode eggs tended to die sooner. Thus, there appears to be a tradeoff between infecting a snail and killing the host.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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

  10. 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

  11. The life cycle of Zygocotyle lunata (Trematoda, Paramphistomoidea in the subtropical region of South America El ciclo de vida de Zygocotyle lunata (Trematoda, Paramphistomoidea en la región subtropical de América del Sur

    Directory of Open Access Journals (Sweden)

    Margarita Ostrowski de Núñez

    2011-06-01

    Full Text Available The life cycle of the trematode Zygocotyle lunata (Diesing, 1836 is studied, beginning with cercariae from naturally infected Biomphalaria peregrina (d'Orbigny, 1835 and B. tenagophila (d'Orbigny, 1835 from Buenos Aires Province and Salta Province (Argentina, respectively. Adults were recovered from Gallus domesticus (Linnaeus, 1758 and Mus musculus (Linnaeus, 1758. Egg development lasted for 15-23 days at 23-24 C, and 10-12 days at 28-30 C; it was delayed after successive passages through mice, and ceased thereafter. In the snail, sporocysts, located beneath the mantle border, occurred up to 37 days post exposure (PE. Rediae invaded the entire snail body; developing cercarial bodies within rediae were recognized by the presence of a short tail, excretory canals, and eye-spot pigment. Cercariae emerged from snails as early as 20-26 days PE, encysting immediately on any substrate. These can be easily differentiated from those of Paramphistomum Fischoeder, 1901 spp. and Cotylophoron Stiles and Goldberger, 1910 spp., which have lateral excretory tubes forming a ring at the midlevel of the body and usually lack pharyngeal appendages. Metacercariae were infective for at least 6 months. Mature adults were observed 27-32 days PE in mice and 35 days PE in chicks. Biomphalaria tenagophila represents a new intermediate natural host record and Salta Province a new geographic area; Dendrocygna viduata (Linnaeus, 1766 and D. bicolor (Vieillot, 1816 from Venezuela are new host records for Z. lunata.El ciclo de vida del trematode Zygocotyle lunata (Diesing, 1836 (Paramphistomoidea: Zygocotylidae fue estudiado experimentalmente, comenzando con cercarias emergidas de Biomphalaria peregrina (d'Orbigny, 1835 y B. tenagophila (d'Orbigny, 1835 infectadas naturalmente, provenientes de las provincias de Buenos Aires y Salta (Argentina, respectivamente. Los adultos fueron obtenidos de Gallus domesticus (Linnaeus, 1758 y Mus musculus (Linnaeus, 1758. El desarrollo del

  12. Simultaneous infection of Schistosoma mansoni and S. rodhaini in Biomphalaria glabrata: impact on chronobiology and cercarial behaviour

    Directory of Open Access Journals (Sweden)

    Richards Louisa

    2008-12-01

    Full Text Available Abstract Background The chances of a schistosome cercaria encountering a suitable definitive host may be enhanced by emergence from the molluscan intermediate host with maximal glycogen stores and by an appropriate chronobiological rhythm. This study aimed to identify and characterize the effects of potential competitive interactions in the snail host Biomphalaria glabrata, between the closely-related Schistosoma mansoni and S. rodhaini, on phenotypic behavioural traits. It was predicted that inter-specific competition would affect chronobiological emergence rhythms and reduce the activity of schistosome swimming behavioural traits. Biomphalaria glabrata snails (120 were exposed to either S. mansoni or S. rodhaini single infections, or a mixed infection of both species simultaneously and the resulting cercarial phenotypic traits were characterised. Cercariae were identified from co-exposed snails by amplification and sequencing of the mitochondrial cytochrome oxidase subunit 1 (CO1. Results S. mansoni and S. rodhaini largely maintained their distinct chronobiological rhythms after mixed exposures and infections. However, inter-specific competition appeared to result in a restriction of the shedding pattern of S. rodhaini and slight shift in the shedding pattern of S. mansoni. Inter-specific competition also significantly lowered hourly cercarial production for both parasite species in comparison to single exposures and infections and reduced cercarial swimming activity. Conclusion Inter-specific competition was shown to influence cercarial production, chronobiology and activity and should therefore be investigated further in field situations to determine the effects of these changes on parasite fitness (incorporating both host finding and infectivity where these two species overlap. Importantly this competition did not result in a large change in chronobiological emergence of cercariae for either species indicating that it would not have a large

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Susceptibility of 7 freshwater gastropod species in Zimbabwe to infection with Gastrodiscus aegyptiacus (Cobbold, 1876 Looss, 1896 : short communication

    Directory of Open Access Journals (Sweden)

    S. Mukaratirwa

    2004-06-01

    Full Text Available Gastrodiscosis outbreaks due to Gastrodiscus aegyptiacus were recorded in horses in the vicinity of Harare, Zimbabwe, in the absence of Bulinus forskalii, B. senegalensis and Cleopatra sp. which are considered to be the only intermediate host snails. This suggested the possibility of other snail species acting as intermediate hosts in the life cycle of the trematode. A study was carried out to determine the susceptibility of 7 freshwater snail species to infection with G. aegyptiacus. First generation (F-1 of 5 freshwater pulmonate snail species, Bulinus tropicus, Bulinus globosus, Biomphalaria pfeifferi, Helisoma dyuri and Physa acuta that were bred in the laboratory, and 2 prosobranch snail species, Melanoides tuberculata and Cleopatra sp. that were collected from the field were used in this study. Data pertaining to mortalities and cercariae shedding were recorded throughout the experimental period. The prosobranch snails, M. tuberculata and Cleopatra sp. were susceptible to G. aegyptiacus with a minimum prepatent period of 45 days and 54 days, respectively. Bulinus tropicus, P. acuta and H. duryi were susceptible as evidenced by the presence of different generations of rediae and mature cercariae on dissection at 59 days post-infection although attempts to induce the snails to shed from 28 days post-infection did not produce cercariae. Bulinus globosus and Bio. Pfeifferi were refractory to infection. The results revealed the ability of G. aegyptiacus to infect M. tuberculata, Cleopatara sp., B. tropicus, P. acuta and H. duryi under experimental conditions and this may explain the recorded outbreaks of gastrodiscosis in equine populations in Zimbabwe in the absence of the known intermediate hosts. Bulinus tropicus is considered as the most likely major intermediate host of G. aegyptiacus because of its wide distribution in Zimbabwe and is well adapted to a wide variety of environments.

  16. Three monoclonal antibodies with specific binding activity to the excretory system of Schistosoma mansoni: an immunoelectron microscopic study using the gold labeling technique.

    Science.gov (United States)

    de Water, R; Fransen, J A; Schut, D W; Deelder, A M

    1987-09-01

    This study describes three monoclonal antibodies against the excretory system of Schistosoma mansoni. Immunofluorescence revealed antigens forming part of the excretory system of cercariae, adult worms, and miracidia, which were located on the luminal membranes of flame and first tubule cells by immunoelectron microscopy. These antigens are either structural components of the membranes or they derive from excretory fluid and are absorbed during transport and ultrafiltration. Binding specificity of the monoclonal antibodies was tested by immunoelectrophoresis and competitive immunofluorescence; one or two antigens were recognized by each. Reactivity of the antigens after treatment with 7.5% trichloroacetic acid or Rossman's fixative demonstrates at least partial polysaccharide content.

  17. 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.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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. Caracterização de cepas de Schistosoma mansoni por morfometria de vermes adultos provenientes de infecção unissexual Characterization of Schistosoma mansoni strains by morphometry of adult worms derived from single-sex infection

    Directory of Open Access Journals (Sweden)

    José Roberto Machado-Silva

    2003-12-01

    Full Text Available Camundongos foram infectados com cercárias, de um único sexo, de cepas simpátricas do Schistosoma mansoni. Nos vermes adultos, foram encontradas diferenças significativas (pMice were infected with only one sex cercaria derived from sympatric strains of Schistosoma mansoni. Adult worms presented significative differences (p<0.05 regarding suckers, testicular lobes, ovary and thickness of the tegument. Data show that morphometric study of unisexual infection worms can be also used for characterization of Schistosoma mansoni strains.

  3. 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...... ponds. Previous risk assessment on FZT transmission in the Red River Delta of Vietnam identified carp nursery ponds as major sites of transmission. In this study, we analyzed the association between snail population density and heterophyid trematode infection in snails with the rate of FZT transmission...

  4. Freshwater snails and Schistosomiasis mansoni in the state of Rio de Janeiro, Brazil: III - Baixadas Mesoregion

    Directory of Open Access Journals (Sweden)

    Silvana C Thiengo

    2002-10-01

    Full Text Available In this paper, the third of a series dealing with the survey of freshwater gastropods of the state of Rio de Janeiro, the results of collections carried out in the Mesoregion Baixadas from 2000 to 2002 are presented. Twenty-two species, belonging to seven families, were found. As to the snail intermediate hosts of Schistosoma mansoni, the most frequent species was Biomphalaria tenagophila besides some new findings of Biomphalaria straminea. No specimens were found harboring larval forms of S. mansoni although different kinds of cercariae had been observed.

  5. Marine and other aquatic dermatoses

    Directory of Open Access Journals (Sweden)

    Jandhyala Sridhar

    2017-01-01

    Full Text Available Occupational and recreational aquatic activity predisposes our population to a wide variety of dermatoses. Sunburn, urticaria, jellyfish stings, and contact dermatitis to rubber equipment are common allergies that are encountered in the aquatic environment. Among the infections, tinea versicolor, intertrigo, and verruca vulgaris are widespread. Swimmer's itch may occur due to skin penetration by schistosome cercariae, while free-floating nematocysts of marine coelenterates may precipitate seabather's eruption. “Suit squeeze” due to cutaneous barotrauma and lymphoedematous peau d'orange due to decompression are rare, described entities. This review serves as a ready reckoner for Indian dermatologists and medical practitioners to identify and manage these conditions.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Effect of photoperiod change on chronobiology of cercarial emergence of Schistosoma japonicum derived from hilly and marshy regions of China.

    Science.gov (United States)

    Wang, Su-Rong; Zhu, Yuan-Jian; Ge, Qing-Peng; Yang, Meng-Jia; Huang, Ji-Lei; Huang, Wen-Qiao; Zhuge, Hong-Xiang; Lu, Da-Bing

    2015-12-01

    The chronobiology of cercarial emergence appeared to be a genetically controlled behavior, adapted to definitive host species, for schistosome. However, a few physiological and ecological factors, for example the change of photoperiod, were reported to affect the rhythmic emergence of cercariae. Therefore, the effect of photoperiod change on cercarial emergence of two Schistosoma japonicum isolates, the hilly and the marshland, was investigated. Four shedding experiments each under a different photoperiod were conducted. Under a natural photoperiod, two distinct shedding modes, one from the hilly region and one from the marshland, were observed. Under a reversed photoperiod, the regular pattern (i.e. under a natural photoperiod) of S. japonicum cercarial emergence was reversed for the marshland isolate and disappeared for the hilly isolate. With an input of a 2 h darkness from 7am to 9am, the cercarial emergence peak were delayed for the two isolates; whereas with an input of a 2 h darkness from 5pm to 7pm, neither effect on the cercarial emergence rhythm was observed. The total cercariae emerged for both parasite isolates varied with a different photoperiod. The results indicate that the change of photoperiod could affect the chronobiology of S japonicum cercarial emergence.

  9. Alguns aspectos referentes ao estudo de linhagens de Schistosoma mansoni Sambon, 1907, provenientes dos Estados de Minas Gerais e de São Paulo, Brasil Some aspects of Schistosoma mansoni strains originating from the States of Minas Gerais and S. Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Raimundo Carlos Lemos Neto

    1978-09-01

    Full Text Available Foram estudados alguns aspectos do comportamento das linhagens mineira (BE e paulista (SJ do S. mansoni. Pesquisou-se a capacidade de penetração das cercárias de ambas as linhagens e a relação granulomas hepáticos-vermes. Verificou-se que as cercárias da linhagem BH possuem maior capacidade de penetração e que o número de granulomas hepáticos por verme, nas duas linhagens, variou inversamente com o número de vermes por camundongo.Some of the behavioral aspects of the Minas Gerais and S. Paulo states' strains Schistosoma mansoni, concerning the penetration capability of cercariae of each strain and the relationship between hepatic granulomata and worms, were studied. The Minas Gerais' strain cercariae present more penetration capability and the ratio between the numbers of hepatic granulomata and number of worms varied inversely with the number of infecting worms per mouse, in both strains.

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

    Directory of Open Access Journals (Sweden)

    Antônio Aurélio Euzébio

    2012-01-01

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

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

    Science.gov (United States)

    Euzébio, Antônio Aurélio; Zuim, Nádia Regina Borim; Linhares, Arício Xavier; Magalhães, Luiz Augusto; Zanotti-Magalhães, Eliana Maria

    2012-01-01

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

  12. Characterization of export receptor exportins (XPOs) in the parasite Schistosoma mansoni.

    Science.gov (United States)

    Abreu, Fabiano C P; Pereira, Roberta V; Oliveira, Victor F; Gomes, Matheus de S; Jannotti-Passos, Liana K; Borges, William C; Guerra-Sá, Renata

    2013-12-01

    Several proteins and different species of RNA that are produced in the nucleus are exported through the nuclear pore complexes, which require a family of conserved nuclear export receptors called exportins (XPOs). It has been reported that the XPOs (XPO1, XPO5, and XPOT) are directly involved in the transport processes of noncoding RNAs from the nucleus to the cytoplasm and/or from cytoplasm to the nucleus. All three genes are present in fungi, plants, and deuterostome metazoans. However, protostome metazoan species lack one of the three genes across evolution. In this report, we have demonstrated that all three XPO proteins are present in the parasite protostome Schistosoma mansoni. As this parasite has a complex life cycle presenting several stages in different hosts and environments, implying a differential gene regulation, we proposed a genomic analysis of XPOs to validate their annotation. The results showed the conservation of exportin family members and gene duplication events in S. mansoni. We performed quantitative RT-PCR, which revealed an upregulation of SmXPO1 in 24 h schistosomula (sixfold when compared with cercariae), and similar transcription levels were observed for SmXPO5 and SmXPOT in all the analyzed stages. These three XPO proteins have been identified for the first time in the protostome clade, which suggests a higher complexity in RNA transport in the parasite S. mansoni. Taken together, these results suggest that RNA transport by exportins might control cellular processes during cercariae, schistosomula, and adult worm development.

  13. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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

  16. Asexual reproduction in Pygospio elegans claparède (Annelida, Polychaeta) in relation to parasitism by Lepocreadium setiferoides (Miller and Northup) (Platyhelminthes, Trematoda).

    Science.gov (United States)

    McCurdy, D G

    2001-08-01

    Life-history theory predicts that parasitized hosts should alter their investment in reproduction in ways that maximize host reproductive success. I examined the timing of asexual reproduction (fragmentation and regeneration) in the polychaete annelid Pygospio elegans experimentally exposed to cercariae of the trematode Lepocreadium setiferoides. Consistent with adaptive host response, polychaetes that became infected by metacercariae of trematodes fragmented sooner than unexposed controls. Parasites were not directly associated with fission in that exposed polychaetes that did not become infected also fragmented earlier than controls. For specimens of P. elegans that were not exposed to trematodes, new fragments that contained original heads were larger than those that contained original tails, whereas original head and tail fragments did not differ in size for infected polychaetes. In infected specimens, metacercariae were equally represented in original head and tail fragments and were more likely to be found in whichever fragment was larger. Despite early reproduction, parasitism was still costly because populations of P. elegans exposed to parasites were smaller than controls when measured 8 weeks later and because exposure to cercariae reduced survivorship of newly divided polychaetes. Taken together, my results suggest that early fragmentation is a host response to minimize costs associated with parasitism.

  17. Pathogenicity of Trichobilharzia spp. for Vertebrates

    Directory of Open Access Journals (Sweden)

    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.

  18. Schistosoma mansoni: migration and attrition of irradiated and challenge schistosomula in the mouse

    Energy Technology Data Exchange (ETDEWEB)

    Mastin, A.J.; Wilson, R.A. (York Univ. (UK)); Bickle, Q.D. (Winches Farm Field Station, St. Albans (UK))

    1983-08-01

    The fate of irradiated, immunizing cercariae and challenge schistosomula was investigated in mice using a quantitative, histological technique which would appear to be more efficient in estimating parasite numbers in skin and lungs than does the tissue mincing and incubation recovery technique used previously by other workers. There was evidence for slight retardation of irradiated parasite migration in skin, but death of schistosomula in the skin appeared negligible. The majority of irradiated parasites remained in the lungs until at least day 21 after infection, and that most schistosomula observed at this time were dead. In mice immunized with irradiated cercariae there was no evidence of attrition of the challenge infection in the skin. The migration profile of challenge parasites in the lungs of immunized animals was not significantly different from that of normal parasites in the lungs of naive animals. Dead challenge parasites were observed in the lungs but their numbers were not considered great enough to account for the final attrition measured by perfusion. It is suggested that the remainder of the attrition of challenge schistosomula may occur in the systemic and/or hepatic portal circulation.

  19. Lack of prezygotic isolation by assortative mating between the two cryptic species of the polytypic Schistosoma intercalatum taxon.

    Science.gov (United States)

    Pagès, J R; Southgate, V R; Tchuem Tchuenté, L A; Jourdane, J

    2001-10-01

    Ten mice were individually exposed to 30 male and 30 female cercariae of Schistosoma intercalatum from Cameroon and to 30 male and 30 female cercariae of S. intercalatum from Zaire. Ten weeks later, the nine surviving mice were killed, and a total of 263 adult schistosomes (228 pairs, 7 unpaired males, 28 unpaired females) were perfused. All worms were identified utilising the random amplified polymorphic DNA technique using primer OPG06 which enables the differentiation of the Cameroon and Zaire genotypes. The data demonstrate that there were no significant differences between the number of homospecific pairs observed compared with the expected number under the null hypothesis. Matings occurred in a random manner indicating that mate choice did not exist for the two genotypes of S. intercalatum. Hence there is no prezygotic isolation mechanism which would prevent the interaction of the two genotypes if they were sympatric. However, as they are allopatric, the possibility of the production of unfit hybrids does not arise. Consequently, the reinforcement of a prezygotic isolating mechanism does not play a significant role in the speciation process.

  20. 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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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.

  2. r-Sm14 - pRSETA efficacy in experimental animals

    Directory of Open Access Journals (Sweden)

    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.

  3. 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

  4. 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.

  5. A molecular genetic study of the variations in metabolic function during schistosome development

    Directory of Open Access Journals (Sweden)

    Patrick J. Skelly

    1995-04-01

    Full Text Available During their complex life cycle schistosomes alternate between the use of stored glycogen and reliance on host glucose to provide for their energy needs. In addition, there is dramatic variation between the relative contribution of aerobic versus anaerobic glucose metabolism during development. We have cloned a set of representative cDNAs that encode proteins involved in glucose uptake, glycolysis, Kreb's cycle and oxidative phosphorylation. The different cDNAs were used as probes to examine the expression of glucose metabolism genes during the schistosome life cycle. Steady state mRNA levels from whole cercariae, isolated cercarial tails, schistosomula and adult worms were analysed on Northern blots and dot blots which were quantified using storage phosphor technology. These studies reveal: (1 Transcripts encoding glycogen metabolic enzymes are expressed to much higher levels in cercarial tails than whole cercariae or schistosomula while the opposite pattern is found for glucose transporters and hexokinase transcripts; (2 Schistosomula contain low levels of transcripts encoding respiratory enzymes but regain the capacity for aerobic glucose metabolism as they mature to adulthood; (3 Male and female adults contain similar levels of the different transcripts involved in glucose metabolism.

  6. Diversity and ancestry of flatworms infecting blood of nontetrapod craniates "fishes".

    Science.gov (United States)

    Orélis-Ribeiro, Raphael; Arias, Cova R; Halanych, Kenneth M; Cribb, Thomas H; Bullard, Stephen A

    2014-01-01

    We herein review all published molecular studies (life history, taxonomy, and phylogeny) and summarize all GenBank sequences and primer sets for the "fish blood flukes". Further, by analysing new and all available sequence data for the partial D1-D2 domains of 28S from 83 blood fluke taxa, we explore the evolutionary expansion of flatworm parasitism in the blood of craniates. Based on this analysis, the blood flukes infecting marine bony fishes (Euteleostei) are monophyletic. The clade comprising the chondrichthyan blood fluke plus the marine euteleost blood flukes is the sister group to tetrapod blood flukes (spirorchiids and schistosomes). The innominate blood fluke cercariae from freshwater gastropods were monophyletic and sister to the clade comprising spirorchiids and schistosomes, but low nodal support indicated that they may represent a distinct blood fluke lineage with phylogenetic affinities also to fish blood flukes. Blood flukes that utilize gastropod intermediate hosts were monophyletic (unidentified gastropod cercariae+tetrapod blood flukes) and those utilizing bivalves and polychaetes were monophyletic (marine fish blood flukes). Low or no taxon sampling among blood flukes of basal fish lineages and primary division freshwater fish lineages are significant data gaps needing closure. We also note that no record of an infection exists in a hagfish (Myxiniformes), lamprey (Petromyzontiformes), or nontetrapod sarcopterygiian, i.e., coelacanth (Coelacanthimorpha) or lungfish (Dipnoi). The present phylogenetic analysis reiterated support for monophyly of Schistosomatidae and paraphyly of spirorchiids, with the blood flukes of freshwater turtles basal to those of marine turtles and schistosomes.

  7. Molecular diversity of avian schistosomes in Danish freshwater snails.

    Science.gov (United States)

    Christiansen, Anne Ø; Olsen, Annette; Buchmann, Kurt; Kania, Per W; Nejsum, Peter; Vennervald, Birgitte J

    2016-03-01

    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 and subjected to molecular investigation by sequencing and phylogenetic analysis of the 5.8S and ITS2 ribosomal DNA for species identification. Additionally, snail hosts belonging to the genus Radix were identified by sequencing and phylogenetic analysis of partial ITS2 ribosomal DNA. Three out of 499 snails 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 are of concern and, particularly, the presence of the potentially neuro-pathogenic species, T. regenti, in Danish freshwaters calls for attention.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Radix natalensis (Gastropoda: Lymnaeidae, a potential intermediate host of Fasciola hepatica in Egypt

    Directory of Open Access Journals (Sweden)

    Dar Y.

    2010-09-01

    Full Text Available Experimental infections of Egyptian Radix natalensis with French miracidia of Fasciola hepatica were carried out to determine if this snail might act as an intermediate host in the life cycle of this digenean in Egypt. Single exposures of R. natalensis to miracidia (2/snail and two successive exposures (a total of 4 miracidia/snail were performed using lymnaeids measuring 1 to 6 mm in height. Live larval forms of F. hepatica were noted in single- and double-exposed snails. In double exposures, a significant increase of snail survival on day 28 post-exposure (at 24 °C and an decrease in prevalence were noted when the height of snails at exposure was increasing. Cercariae of F. hepatica were shed by these snails (90.7/snail during a mean patent period of 24.3 days. All snails have released these cercariae during 2-13 waves of shedding. According to these results, R. natalensis can be considered a potential intermediate host of F. hepatica in Egypt.

  14. Ivermectin efficacy against Biomphalaria, intermediate host snail vectors of Schistosomiasis.

    Science.gov (United States)

    Katz, Naftale; Araújo, Neusa; Coelho, Paulo Marcos Zech; Morel, Carlos Medicis; Linde-Arias, Ana Rosa; Yamada, Takeshi; Horimatsu, Yuki; Suzuki, Koh; Sunazuka, Toshiaki; Ōmura, Satoshi

    2017-03-15

    The impact of ivermectin on adult snails of the genus Biomphalaria (B. glabrata, B. tenagophila and B. straminea), B. glabrata infected with Schistosoma mansoni, snail egg-masses cercariae and miracidia, as well as on guppy fish (Poecilia reticulata) was examined and evaluated. Biomphalaria snails, egg-masses, parasite stages and guppies were all exposed to different concentrations of ivermectin for 24 h, followed by regular observations of mortality. The calculated lethal doses of ivermectin were around an LD50 of 0.03 μg ml(-1), and an LD90 of 0.3 μg ml(-1) for the three species of snails. Specimens of B. glabrata actually shedding parasite cercariae all died when exposed to ivermectin at a concentration of a mere 0.01 μg ml(-1). Ivermectin B1a, the major (80%) component of commercially available ivermectin, proved to be inactive, and it was the minor (20%) component, ivermectin B1b, which caused snail death. Snail egg-masses were not affected, even at the highest concentration of 100 μg ml(-1). With respect to S. mansoni parasite stages, 0.2 μg ml(-1) ivermectin killed 50% of cercariae and miracidia within five minutes, rising to 90% after 30 min. Mortality of guppy fish within 24 h of exposure to ivermectin at concentrations of 0.5 μg ml(-1) and 0.01 μg ml(-1), were 100% and 30%, respectively. The concentration of 0.01 μg ml(-1) that killed Schistosoma mansoni-infected snails only caused 30% mortality in guppy fish. Ivermectin can be considered a promising molluscicide, especially as it is more potent against infected snails than uninfected ones, although it has no impact on egg-masses. Ivermectin and its derivatives could be explored in the search for a new agent to help control schistosomiasis transmission.The Journal of Antibiotics advance online publication, 15 March 2017; doi:10.1038/ja.2017.31.

  15. Distribution of trematodes in snails in ponds at integrated small-scale aquaculture farms.

    Science.gov (United States)

    Boerlage, Annette S; Graat, Elisabeth A M; Verreth, Johan A; de Jong, Mart C M

    2013-03-01

    In integrated small-scale aquaculture farming, animal and human excreta maybe used as fish feed and pond fertilizer, thereby enhancing transmission of fish-borne zoonotic trematodes (FZTs) from final hosts, like humans, pigs and chickens, to snails. Areas within a pond could vary in trematode egg-load due to the immediate bordering land, and this might provide implications for control of these trematodes or sampling in field studies measuring FZT prevalence in snails. We therefore estimated the effect of bordering land use on prevalence and FZT burden in snails in different areas within small-scale aquaculture ponds. Nine sampling areas within a pond were assigned in six ponds. For each sampling area, about 120 Melanoides tuberculata snails were collected. Based on land use bordering a sampling area, these were categorized in 5 risk-categories: low-risk (road, rice planted in pond, agriculture, or middle of pond), human access point to pond, livestock sty (pigs or poultry), both human access point and livestock sty, and water connection to canal. In total, 5392 snails were collected. Percentages of snails with parapleurolophocercous cercariae varied between 6% in areas categorized as low-risk and areas with livestock sty only to 15% in areas with both human access point and livestock sty; only this 15% was significantly different from the prevalence in the low-risk category. Percentages of snails with xiphidio cercariae did not differ between risk-categories and varied between 5% and 10%. Mean snail size was 15.2mm, and was significantly associated with both the probability of infection as well as parasite burden. Very small differences in parasite burden were found at different land use areas; the maximum difference was about 11 cercariae. This study demonstrated only small differences between areas surrounding a pond on risk of snails to be infected with fish-borne trematodes within different pond areas. In field studies on FZTs in M. tuberculata snails in ponds

  16. [Intestinal schistosomiasis in the freshwater mangrove of Guadalupe (French Antilles). Ecology of the vector, Biomphalaria glabrata and its parasite Schistosoma mansoni (author's transl)].

    Science.gov (United States)

    Pointier, J P; Theron, A

    1979-01-01

    In the freshwater mangrove of Dubelloy-Devarieux (Guadalupe), the dynamics of populations of B. glabrata and the transmission of S. mansoni, mostly depends on the alternation of dry and rainy season. The flooding of the mangrove (in september), permits a yearly renewal of the malacological populations. The sizes analysis of the snails shows that the life cycle of B. glabrata include two rainy seasons separated by one dry season. The prevalence of B. glabrata (0,25%) and cercariae densities (0,8 c/l) are very slow. The acrophase of the rhythm of presence in standing waters is reached at 2 pm. Men and rats are infected. The infections of rats is of 20% at the beginning of the rainy season and of 100% at the end of the rainy season. Principal factors involved in the infection of rats are discussed.

  17. 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.

  18. 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.

  19. 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.

  20. Susceptibility of Biomphalaria alexandrina to the plant Azolla pinnata and some herbicides in relation to infection with Schistosoma mansoni miracidia.

    Science.gov (United States)

    Zidan, Z H; Hafez, A M; Abdel-Megeed, M I; el-Emam, M A; Ragab, F M; el-Deeb, F A

    1998-04-01

    Molluscicidal activity of the herebicides 2,4-D and Graminol, as well as both extracts and dry powder of the plant Azolla pinnata were evaluated against B. alexandrina snails. It was observed that 2,4-D proved to be the most toxic compound among he tested ones, showing LC90 of 52 ppm after 24 h of exposure. Ethanol extract of Azolla showed the highest molluscicidal activity against the tested snails compared with the other extracts and dry powder (LC90 = 3300 ppm). Ethanol extract at 6600 ppm after 3 h of exposure killed 100% and 19.4% of S. mansoni miracidia and cercariae, respectively. The molluscicidal activity of 2,4-D was not influenced by the presence of Azolla (900 plants/liter) for 7 days, while Graminol effect was significantly reduced. However, the infectivity of S. mansoni miracidia to B. alexandrina snails was not affected by Azolla existence.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Immunoelectron microscopical localization of a circulating antigen in the excretory system of Schistosoma mansoni. Ultrastructural localization studies of the excretory system of S. mansoni.

    Science.gov (United States)

    Bogers, J J; Nibbeling, H A; Van Marck, E A; Deelder, A M

    1995-01-01

    In this study the excretory system of Schistosoma mansoni was ultrastructurally examined with a recently described monoclonal antibody (mAb) against a circulating antigen. In previous studies this mAb was found to have affinity for the excretory system. Strong immunoreactivity was found on the flagella of the flame cells and of the collecting ducts throughout the worm. The eggshell and the space between the miracidium and the eggshell showed strong reactivity with a declining gradient towards the exterior, suggesting a secretion process. In cercariae, immunoreactivity was restricted to the tegument, whereas in schistosomula the labeling pattern resembled that of the adult worm, demonstrating positive reactivity of the flame cells and no immunostaining of the tegument. This stage-dependent differential expression of different antigens in the excretory system and in the tegument could suggest a maturation process of the excretory system.

  3. The schistosome excretory system: a key to regulation of metabolism, drug excretion and host interaction.

    Science.gov (United States)

    Kusel, John R; McVeigh, Paul; Thornhill, Joyce A

    2009-08-01

    There is a gulf between the enormous information content of the various genome projects and the understanding of the life of the parasite in the host. In vitro studies with adult Schistosoma mansoni using several substrates suggest that the excretory system contains both P-glycoproteins and multiresistance proteins. If both these families of protein were active in vivo, they could regulate parasite metabolism and be responsible for the excretion of drugs. During skin penetration, membrane-impermeant molecules of a wide range of molecular weights can be taken into the cercaria and schistosomulum through the nephridiopore, through the surface membrane or through both. We speculate that this uptake process might stimulate novel signalling pathways involved in growth and development.

  4. 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%

  5. [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.

  6. 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.

  7. 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

  8. Associations between trematode infections in cattle and freshwater snails in highland and lowland areas of Iringa Rural District, Tanzania.

    Science.gov (United States)

    Nzalawahe, Jahashi; Kassuku, Ayub A; Stothard, J Russell; Coles, Gerald C; Eisler, Mark C

    2015-09-01

    The epidemiology of trematode infections in cattle was investigated within highland and lowland areas of Iringa Rural District, in southern Tanzania. Fecal samples were collected from 450 cattle in 15 villages at altitudes ranging from 696 to 1800 m above the sea level. Freshwater snails were collected from selected water bodies and screened for emergence of cercariae. The infection rates in cattle were Fasciola gigantica 28·2%, paramphistomes 62·8% and Schistosoma bovis 4·8%. Notably, prevalence of trematode infections in cattle was much higher in highland (altitude > 1500 m) as compared with lowland (altitude snails collected included Lymnaea natalensis, Bulinus africanus, Bulinus tropicus, Bulinus forskali, Biomphalaria pfeifferi, Melanoides tuberculata and Bellamya constricta with a greater proportion of highland (75%) than lowland (36%) water bodies harbouring snails. Altitude is a major factor shaping the epidemiology of F. gigantica and paramphistomes infections in cattle in Iringa Rural District with greater emphasis upon control needed in highland areas.

  9. 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.

  10. 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...

  11. 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...... and subjected to molecular investigation by sequencing and phylogenetic analysis of the 5.8S and ITS2 ribosomal DNA for species identification. Additionally, snail hosts belonging to the genus Radix were identified by sequencing and phylogenetic analysis of partial ITS2 ribosomal DNA. Three out of 499 snails...

  12. A comparative parasitologic study on Biomphalaria glabrata snail and C3H/He mice infected with human and murine isolates of Schistosoma mansoni derived from Sumidouro, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Nilcéa Freire

    2003-09-01

    Full Text Available Experiments were carried out to analyze the biological characteristics of two sympatric isolates of Schistosoma mansoni derived from humans and murines in a low endemic transmission area (Sumidouro county, state of Rio de Janeiro, Brazil. Sympatric reared-laboratory Biomphalaria glabrata and C3H/He mice were used as experimental hosts. Parameters assessed comprised: precercarial period, infectivity and mortality (snails, prepatent period, infectivity (percentage of cercariae maturation into adult worm and intestinal egg count (mice. The murine isolate showed a shorter precercarial period and higher infectivity than human isolate (p 0.05. These data suggest that both isolates are local sub-populations, providing support for the hypotheses that in a same biotope mixed populations or sub-populations circulate among their main host (human beings and/or rodent as an anfixenous infection.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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.

  15. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Infecção experimental de camundongos albinos com cercárias de Schistosoma mansoni Sambon, 1907, previamente submetidas a ação de termofosfato magnesiano

    Directory of Open Access Journals (Sweden)

    Roberto Milward-de-Andrade

    1989-04-01

    Full Text Available Foi realizada infecção experimental de camundongos albinos ("Swiss inbred" com cercárias de Schistosoma mansoni, cepa LE, submetidas à ação do adubo termofosfato magnesiano (Tfm, usualmente utilizado em latossolos tropicais e capaz, quando ingerido, de provocar o bloqueio da ovogênese de moluscos planorbídeos. Nas condições do experimento, observou-se a infecção dos roedores. Porém, o número de ovos eliminados pelo grupo controle, representado por cinco camundongos, foi sensivelmente maior que o do grupo Tfm, ainda que a recuperação de vermes, por perfusão, tenha sido bem menor. Do grupo Tfm, foram recuperados 163 (98,2% vermes adultos machos e apenas 3 (1,8% fêmeas, isoladas. Do grupo controle, a perfusão proporcionou 53 vermes adultos, sendo 13 machos, 18 fêmeas e 11 casais. Cada camundongo foi exposto a 150 cercárias.Experimental infection of white mice (Swiss inbred with LE strain Scistosoma mansoni cercariae submitted to the action of magnesium thermophosphate (Tfm, usually used in tropical latosoils, was performed. This product is able to block ovogenesis of planorbid molluscs. In these experimental conditions, rodents were infected. But, the number of eggs released by the control group (five mice was markedly greater than that of the Tfm group, although a short number of worms were recovered by perfusion. From the Tfm group, 163 adult worms (98,2% were recovered and only 3 females (1,8%. Of the control group, perfusion recovered 62 adult worms (22 male worms, 18 female and 11 couples. Each mice was exposed to 150 cercariae.

  18. Opisthorchis viverrini infection in the snail and fish intermediate hosts in Central Vietnam.

    Science.gov (United States)

    Dao, Ha Thanh Thi; Dermauw, Veronique; Gabriël, Sarah; Suwannatrai, Apiporn; Tesana, Smarn; Nguyen, Giang Thanh Thi; Dorny, Pierre

    2017-02-24

    Opisthorchis viverrini, a carcinogenic fish borne fluke, requires freshwater snails and fish as intermediate hosts. Opisthorchiasis is endemic in parts of Southeast Asia, including Central and South Vietnam. In this region the transmission by intermediate hosts has received little attention. Therefore, freshwater snails and wild fish from Bau My Tho, an opisthorchiasis endemic area in Binh Dinh Province were collected for examination of O. viverrini cercariae and metacercariae, respectively. A total of 12,000 snails belonging to six families, of which 1616 Bithynia snails representing Bithynia siamensis goniomphalos and Bithynia funiculata; as well as 754 fish representing 12 species were examined. Shedding of O. viverrini cercariae was observed only in B. s. goniomphalos and B. funiculata, at infection rates of 0.86% and 0.14%, respectively. O. viverrini infection in Bithynia spp. was significantly associated with the habitat but not with the species and the shell size of Bithynia spp. O. viverrini metacercariae were found in 10 fish species representing both Cyprinidae and non-Cyprinidae families. The prevalence of O. viverrini infection in fish was significantly associated with species. Carassius auratus, a fish species commonly eaten raw, Rasbora aurotaenia and Puntius brevis had the highest prevalence of 74.0%, 55.8% and 31.6%, respectively. Sharing of the same snail and fish intermediate host species was found for O. viverrini and a O. viverrini duck-genotype that are sympatric in the study region. This study is the first to report on the intermediate host species of O. viverrini in Central Vietnam and indicates a high risk of acquiring opistorchiasis when eating raw fish dishes.

  19. The Mannose Receptor (CD206) is an important pattern recognition receptor (PRR) in the detection of the infective stage of the helminth Schistosoma mansoni and modulates IFNγ production.

    Science.gov (United States)

    Paveley, Ross A; Aynsley, Sarah A; Turner, Joseph D; Bourke, Claire D; Jenkins, Stephen J; Cook, Peter C; Martinez-Pomares, Luisa; Mountford, Adrian P

    2011-11-01

    In this study, infective larvae of the parasitic helminth Schistosoma mansoni were shown to contain a large number of glycosylated components specific for the Mannose Receptor (MR; CD206), which is an important pattern recognition receptor (PRR) of the innate immune system. MR ligands were particularly rich in excretory/secretory (E/S) material released during transformation of cercariae into schistosomula, a process critical for infection of the host. E/S material from carboxyfluorescein diacetate succinimidyl ester (CFDA-SE)-labelled cercariae showed enhanced binding by cells lines that over-express the MR. Conversely, uptake was significantly lower by bone marrow-derived macrophages (MΦ) from MR(-/-) mice, although they were more active as judged by enhanced pro-inflammatory cytokine production and CD40 expression. After natural percutaneous infection of MR(-/-) mice with CFDA-SE-labelled parasites, there were fewer cells in the skin and draining lymph nodes that were CFDA-SE(+) compared with wild-type mice, implying reduced uptake and presentation of larval parasite antigen. However, antigen-specific proliferation of skin draining lymph node cells was significantly enhanced and they secreted markedly elevated levels of IFNγ but decreased levels of IL-4. In conclusion, we show that the MR on mononuclear phagocytic cells, which are plentiful in the skin, plays a significant role in internalising E/S material released by the invasive stages of the parasite which in turn modulates their production of pro-inflammatory cytokines. In the absence of the MR, antigen-specific CD4(+) cells are Th1 biased, suggesting that ligation of the MR by glycosylated E/S material released by schistosome larvae modulates the production of CD4(+) cell specific IFNγ.

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

    Directory of Open Access Journals (Sweden)

    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

  1. In Vitro Assessment of Anthelmintic Activities of Rauwolfia vomitoria (Apocynaceae Stem Bark and Roots against Parasitic Stages of Schistosoma mansoni and Cytotoxic Study

    Directory of Open Access Journals (Sweden)

    Emmanuel Mouafo Tekwu

    2017-01-01

    Full Text Available Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemotherapy. The reliance on a single drug, praziquantel, is a motivation for the search of novel antischistosomal compounds. This study investigated the anthelmintic activity of the stem bark and roots of Rauwolfia vomitoria against two life stages of Schistosoma mansoni. Both plant parts were found to be active against cercariae and adult worms. Within 2 h of exposure all cercariae were killed at a concentration range of 62.5–1000 µg/mL and 250–1000 µg/mL of R. vomitoria stem bark and roots, respectively. The LC50 values determined for the stem bark after 1 and 2 h of exposure were 207.4 and 61.18 µg/mL, respectively. All adult worms exposed to the concentrations range of 250–1000 µg/mL for both plant parts died within 120 h of incubation. The cytotoxic effects against HepG2 and Chang liver cell assessed using MTT assay method indicated that both plant extracts which were inhibitory to the proliferation of cell lines with IC50 > 20 μg/mL appear to be safe. This report provides the first evidence of in vitro schistosomicidal potency of R. vomitoria with the stem bark being moderately, but relatively, more active and selective against schistosome parasites. This suggests the presence of promising medicinal constituent(s.

  2. Variation among genotypes in responses to increasing temperature in a marine parasite: evolutionary potential in the face of global warming?

    Science.gov (United States)

    Berkhout, Boris W; Lloyd, Melanie M; Poulin, Robert; Studer, Anja

    2014-11-01

    Climates are changing worldwide, and populations are under selection to adapt to these changes. Changing temperature, in particular, can directly impact ectotherms and their parasites, with potential consequences for whole ecosystems. The potential of parasite populations to adapt to climate change largely depends on the amount of genetic variation they possess in their responses to environmental fluctuations. This study is, to our knowledge, the first to look at differences among parasite genotypes in response to temperature, with the goal of quantifying the extent of variation among conspecifics in their responses to increasing temperature. Snails infected with single genotypes of the trematode Maritrema novaezealandensis were sequentially acclimatised to two different temperatures, 'current' (15°C) and 'elevated' (20°C), over long periods. These temperatures are based on current average field conditions in the natural habitat and those predicted to occur during the next few decades. The output and activity of cercariae (free-swimming infective stages emerging from snails) were assessed for each genotype at each temperature. The results indicate that, on average, both cercarial output and activity are higher at the elevated acclimation temperature. More importantly, the output and activity of cercariae are strongly influenced by a genotype-by-temperature interaction, such that different genotypes show different responses to increasing temperature. Both the magnitude and direction (increase or decrease) of responses to temperature varied widely among genotypes. Therefore, there is much potential for natural selection to act on this variation, and predicting how the trematode M. novaezealandensis will respond to the climate changes predicted for the next century will prove challenging.

  3. Increased surfacing behavior in longnose killifish infected by brain-encysting trematode.

    Science.gov (United States)

    Fredensborg, B L; Longoria, A N

    2012-10-01

    Some parasites modify the behavior of intermediate hosts to increase the probability of transmission to the next host in their life cycle. In habitats where this is common, parasites play an important role in predator-prey links and food web dynamics. In this study we used laboratory observations to investigate the behavior of longnose killifish, Fundulus similis, that were naturally infected with metacercariae of the trematode, Euhaplorchis sp. A, from Laguna Madre, south Texas. In particular, we examined whether there was a relationship between the number of metacercariae lodged on the brain of the infected fish and behaviors that made the fish more conspicuous to avian final hosts. We also quantified the abundance and cercariae production of this parasite in its first intermediate snail host, Cerithidea pliculosa , and examined the seasonal variation of Euhaplorchis sp. A in F. similis . Our data demonstrated that Euhaplorchis sp. A affected the surfacing behavior of F. similis in an intensity-dependent manner. Fish with many infections spent longer time at the surface of the water than fish with few infections. Our data also show that Euhaplorchis sp. A is a common parasite in the first intermediate host and produces close to 4,000 cercariae m(-2) day(-1). Consequently 97% of all fish collected and necropsied were infected, with little seasonal variation in the mean abundance of the parasite. Based on our data, Euhaplorchis sp. A is likely important to predator-prey links in Gulf of Mexico estuary food webs, similar to the closely related Euhaplorchis californiensis in southern California. We expect that other closely related species elsewhere may have similar effects on other fish hosts, emphasizing the need for incorporating trophically transmitted parasites in estuarine food web studies.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Comparative Transcriptomic Exploration Reveals Unique Molecular Adaptations of Neuropathogenic Trichobilharzia to Invade and Parasitize Its Avian Definitive Host.

    Science.gov (United States)

    Leontovyč, Roman; Young, Neil D; Korhonen, Pasi K; Hall, Ross S; Tan, Patrick; Mikeš, Libor; Kašný, Martin; Horák, Petr; Gasser, Robin B

    2016-02-01

    To date, most molecular investigations of schistosomatids have focused principally on blood flukes (schistosomes) of humans. Despite the clinical importance of cercarial dermatitis in humans caused by Trichobilharzia regenti and the serious neuropathologic disease that this parasite causes in its permissive avian hosts and accidental mammalian hosts, almost nothing is known about the molecular aspects of how this fluke invades its hosts, migrates in host tissues and how it interacts with its hosts' immune system. Here, we explored selected aspects using a transcriptomic-bioinformatic approach. To do this, we sequenced, assembled and annotated the transcriptome representing two consecutive life stages (cercariae and schistosomula) of T. regenti involved in the first phases of infection of the avian host. We identified key biological and metabolic pathways specific to each of these two developmental stages and also undertook comparative analyses using data available for taxonomically related blood flukes of the genus Schistosoma. Detailed comparative analyses revealed the unique involvement of carbohydrate metabolism, translation and amino acid metabolism, and calcium in T. regenti cercariae during their invasion and in growth and development, as well as the roles of cell adhesion molecules, microaerobic metabolism (citrate cycle and oxidative phosphorylation), peptidases (cathepsins) and other histolytic and lysozomal proteins in schistosomula during their particular migration in neural tissues of the avian host. In conclusion, the present transcriptomic exploration provides new and significant insights into the molecular biology of T. regenti, which should underpin future genomic and proteomic investigations of T. regenti and, importantly, provides a useful starting point for a range of comparative studies of schistosomatids and other trematodes.

  6. Comparative Transcriptomic Exploration Reveals Unique Molecular Adaptations of Neuropathogenic Trichobilharzia to Invade and Parasitize Its Avian Definitive Host.

    Directory of Open Access Journals (Sweden)

    Roman Leontovyč

    2016-02-01

    Full Text Available To date, most molecular investigations of schistosomatids have focused principally on blood flukes (schistosomes of humans. Despite the clinical importance of cercarial dermatitis in humans caused by Trichobilharzia regenti and the serious neuropathologic disease that this parasite causes in its permissive avian hosts and accidental mammalian hosts, almost nothing is known about the molecular aspects of how this fluke invades its hosts, migrates in host tissues and how it interacts with its hosts' immune system. Here, we explored selected aspects using a transcriptomic-bioinformatic approach. To do this, we sequenced, assembled and annotated the transcriptome representing two consecutive life stages (cercariae and schistosomula of T. regenti involved in the first phases of infection of the avian host. We identified key biological and metabolic pathways specific to each of these two developmental stages and also undertook comparative analyses using data available for taxonomically related blood flukes of the genus Schistosoma. Detailed comparative analyses revealed the unique involvement of carbohydrate metabolism, translation and amino acid metabolism, and calcium in T. regenti cercariae during their invasion and in growth and development, as well as the roles of cell adhesion molecules, microaerobic metabolism (citrate cycle and oxidative phosphorylation, peptidases (cathepsins and other histolytic and lysozomal proteins in schistosomula during their particular migration in neural tissues of the avian host. In conclusion, the present transcriptomic exploration provides new and significant insights into the molecular biology of T. regenti, which should underpin future genomic and proteomic investigations of T. regenti and, importantly, provides a useful starting point for a range of comparative studies of schistosomatids and other trematodes.

  7. 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,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.

  8. Preliminary investigation on in vitro-cultivation and manipulation of Schistosoma japonicum sporocysts%日本血吸虫胞蚴的体外培养和操作初探

    Institute of Scientific and Technical Information of China (English)

    江艳; 龚仁敏; 杨艺; 李小红; 刘毅; 朱传刚; 陆珂; 郑浩

    2011-01-01

    目的 探究一种体外培养日本血吸虫胞蚴的新方法,并通过体外注射,感染阴性钉螺,培养阳性钉螺.方法 将日本血吸虫虫卵孵化的毛蚴与作为滋养层的草地夜蛾(Spodoptera frugiperda)卵巢细胞(sf9细胞)共培养,观察毛蚴的生长情况,并拍摄生长照片.用显微注射针将3~5只母胞蚴注射到钉螺体内,计算钉螺的存活率及尾蚴的阳性率,用钉螺逸出的尾蚴人工感染昆明鼠,检测尾蚴的活力,用组织化学染色法和PCR方法鉴定尾蚴的相关基因特性.结果 毛蚴培养至第12小时观察到纤毛板已脱落,培养2~3 d的虫体呈不断的伸缩运动,此后母胞蚴维持该状态并不转化成子胞蚴.3次实验的钉螺存活率依次为24.72%、28.23%和57.89%,活螺阳性率依次为4.55%、8.57%和14.29%.阳性钉螺释放的尾蚴具有感染性,且具有与日本血吸虫相同的基因特性.结论 体外培养毛蚴通过显微注射可以人工感染钉螺并逸出有感染活力的尾蚴,为日本血吸虫幼虫的体外操作提供一种新的方法.%Objective To explore a new method of in vitro cultivation of Schistosoma japonicum sporocysts,infection of negative snails through in vitro-injection,and cultivation of positive snails.Methods Isolated miracidia were directly cultivated in sf9 cells-conditioned medium,the growth of miracidia was observed and the growth picture was taken.3-5 mother sporocysts were inoculated into the snails body using a microscopic needle.The survival rate of the snails and the positive rate of cercariae were calculated.Kunming mice were infected with the cercariac and the activity of cercariae Was detected.The related gene characteristics of cercariae was identified by histochemical examination and PCR method.Results The pictures of miracidia were recorded after co-cultivation for 1 h,12 h,24 h and 3 d.The shedding of the cilia of miracidia occurred within 12 h,parasites exhibited continuous stretching movements after

  9. [The Wormicidal Substances Of Fresh Water Fishes On Clonorchis Sinensis: II. Preliminary Research On The Wormicidal Substances From Mucous Substances Of Various Fresh Water Fishes

    Science.gov (United States)

    Rhee, Jae Ku; Baek, Byeong Kirl; Ahn, Byung Zun; Park, Young Jun

    1980-06-01

    The present work which was investigated in July 1979, was to observe the wormicidal effects of the external mucous substances of 9 species of fresh water fishes (Cyprinus carpio, Parasilurus asotus, Anguilla japonica, Ophicephalus argus, Carassius carassius; golden crusian carp, Misgurnus anguillicaudatus, Zacco platypus, Pseudorasbora parva and Carassius carassius; crusian carp) on cercaria, liberated metacercaria and adult of Clonorchis sinensis. The mucous substances extracted by ether from the above 9 species of fishes were separated into many spots on the silica gel thin layer chromatography, and divided into many fractions in the silica gel column chromatography which used petroleum ether (30%) and chloroform (70%) as a solvent. 1. On the silica gel thin layer chromatography of ether extracts from 9 species of fresh water fishes, each of the Rf. values which had wormicidal effect on the cercaria of C. sinensis were different from others; Rf. value of C. carassius (crusian carp) was 0.937, 0.709 in O. argus, 0.612 in A. japonica, 0.576 in P. asotus, 0.451 in C. carpio, 0.701 in Z. platypus, 0.385 in C. carassius(golden crusian carp) and 0.15 in P. parva. Time for wormicide was different from each other, too. It took 14 min. in a case of C. carassius(crusian carp), 25 min. in Z. platypus, 26 min. in C. carassius(golden crusian carp), 28 min. in C. carpio, 30 min. in P. asotus, 35 min. in O. argus, 40 min. P. parva and 180 min. in A. japonica. But any of the spots of M. anguillicaudatus did not show wormicidal effect on the cercaria within 10 hours. 2. In the silica gel column chromatography of ether extracts from 9 species of fresh water fishes, the fractions which had wormicidal effect on the metacercaria of C. sienesis were different from each other; in a case of C. carassius(crusian carp), the first fraction only had wormicidal effect, the 2nd in P. asotus, the 3rd in O. argus, the 4th in C. carassius(golden crusian carp), the 2nd in C. carpio and the 4th in

  10. Impact of trematode parasitism on the fauna of a North Sea tidal flat

    Science.gov (United States)

    Lauckner, G.

    1984-03-01

    The impact of larval trematodes on the fauna of a North Sea tidal flat is considered at the individual and at the population level, depicting the digenean parasites of the common periwinkle, Littorina littorea, and their life cycles, as an example. On the German North Sea coast, L. littorea is first intermediate host for 6 larval trematodes representing 6 digenean families — Cryptocotyle lingua (Heterophyidae), Himasthla elongata (Echinostomatidae), Renicola roscovita (Renicolidae), Microphallus pygmaeus (Microphallidae), Podocotyle atomon (Opecoelidae) and Cercaria lebouri (Notocotylidae). All except P. atomon utilize shore birds as final hosts; adult P. atomon parasitize in the intestine of teleosts, mainly pleuronectid flatfish. Second intermediate hosts of C. lingua are various species of fish; the cercariae of H. elongata encyst in molluscs and polychaetes, those of R. roscovita in molluscs; M. pygmaeus has an abbreviated life cycle; C. lebouri encysts free on solid surfaces; and the fish trematode P. atomon utilizes benthic crustaceans, mainly amphipods, as second intermediate hosts. On the tidal flats of the Königshafen (Sylt), up to 77% of the periwinkles have been found to be infested by larval trematodes. Maximum infestations in individual samples were 23% for C. lingua, 47% for H. elongata and 44% for R. roscovita. The digeneans cause complete ‘parasitic castration’ of their carriers and hence exclude a considerable proportion of the snails from the breeding population. Infestation reduces the longevity of affected hosts, and size-related, trematode-induced differential mortality causes changes in the normal size-frequency distribution of individual snail-age classes. Young flatfish Pleuronectes platessa from the Königshafen are 100% infested with metacercariae of C. lingua. Heavy infestation of the gills causes obstruction of blood vessels and respiratory impairment; metacercariae in the eyes and optic nerves cause visual and neurological

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

    Directory of Open Access Journals (Sweden)

    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.

  12. The invasive Chinese pond mussel Sinanodonta woodiana (Lea, 1834 as a host for native symbionts in European waters

    Directory of Open Access Journals (Sweden)

    Anna Cichy

    2016-01-01

    Full Text Available Biological invasions are commonly observed in both the natural habitats and those which are altered by human activities. An understanding of the mechanisms involved in the successful introduction, establishment and invasion of exotic taxa is essential in predicting of changes in biodiversity and community structure. Symbiont-mediated interactions between exotic and native hosts are of special interest due to the indirect effects on population dynamics. The aim of this study was to estimate the presence of symbionts in Chinese pond mussel Sinanodonta woodiana (Lea, 1834, an exotic species of mussel in European fresh waters. The number of 340 individuals of S. woodiana was collected from Polish water bodies, including thermally heated lakes and fish ponds with natural thermal regime. The examination of mussels revealed the presence of Rhipidocotyle campanula sporocysts and cercariae (Digenea: Bucephalidae, water mites Unionicola ypsilophora (Acari: Hydracarina, oligochaetes Chaetogaster limnaei limnaei (Oligochaeta: Naididae and chironomids Glyptotendipes sp. (Diptera: Chironomidae. The global prevalence of mussels inhabited by Ch. limnaei limnaei was 7.6%, by water mites and chironomids 3.5%, and by R. campanula cercariae 2.0%. The significant difference in the number of mussels with symbionts was identified between heated lakes and fish ponds (χ2=4.15; df=1, P=0.04, with a higher global prevalence of mussels in fish ponds (22.3% compared to heated lakes (13.7%. R. campanula or U. ypsilophora were only found in mussels collected from thermally polluted lakes or fish ponds, respectively. Chironomid larvae and oligochaetes occurred in both types of water bodies. However, Glyptotendipes sp. inhabited mussels with a higher global prevalence in fish ponds than in thermally polluted lakes, while Ch. limnaei limnaei was observed mainly in hosts from heated lakes, and only from one fish pond that were not drained. Our findings indicate that the alien

  13. Estudo sobre o papel dos eosinofilos na destruição dos esquistossomulos do Schistosoma mansoni in vivo: (Nota prévia Role of eosinophils in destruction of schistosomula of Schistosoma mansoni in vivo (preliminary report

    Directory of Open Access Journals (Sweden)

    Zilton A. Andrade

    1984-09-01

    Full Text Available Esquistossômulos obtidos através de processo mecânico foram injetados na veia da cauda de camundongos Balb/c (2.000 esquist./0,15ml e as reações pulmonares foram estudadas histologicamente após 24, 48, 72 e 96 horas. Os animais estavam divididos em quatro grupos: 1 animais normais injetados com esquistossômulos vivos; 2 animais normais injetados com esquistossõmulos mortos; 3 animais infectados há dez semanas com 30 cercárias do Schistosoma mansoni e injetados com esquistossômulos vivos e 4 animais semelhantes aos do grupo acima, mas injetados com esquistossômulos mortos. As reações pulmonares bem desenvolvidas em torno dos esquistossômulos, só foram observadas nos animais injetados com esquistossômulos mortos e foram mais intensas e com maior quantidade de eosinófilos nos animais já infectados. estes resultados diferem daqueles observados in vitro, em que os esquistossômulos são destruídos por um sistema composto de anticorpos específicos, complemento e eosinófilos, estas últimas células destruindo as larvas por citoaderência, degranulação e citotoxidade. O presente trabalho indica que in vitro a infilstração de eosinófilos ocorre após a morte das larvas, no animal sensibilizado.Schistosoma mansoni cercariae mechanically transformed into schistosomula were injected, eitherdead or alive, into the tail vein (2.000 larvae/0,15ml of Balb/c mice which were either previously infected with S. mansoni (10 weeks/50 cercariae or non-infected. Histological examination of the lungs 24,48,72 and 96 hours after injection revealed that inflammatory reaction around schistosomula occurred only in the groups injected with dead schistosomula (killed by freezing and thawing. in non-infected animals the reaction was predominantly macrophagic while in those infected many eosinophis appeared around the dead larvae. These results are at variance with those obtained in vitro and suggest that in vitro the participation of eosinophils in

  14. Epidemiological study on Clonorchis sinensis infection in Shenzhen area of Zhujiang delta in China.

    Science.gov (United States)

    Zhang, Renli; Gao, Shitong; Geng, Yijie; Huang, Dana; Yu, Lei; Zhang, Shunxiang; Cheng, Jingquan; Fu, Yucai

    2007-06-01

    To study the transmission route and epidemiological features of Clonorchis sinensis infection in Shenzhen area, which is the biggest immigration city in the south of China, we examined 1,473 individuals (710 males and 763 females) to assess the current status of C. sinensis infection among the people in a village of Shenzhen in Zhujiang delta of Guangdong province, China. Freshwater snails, 630, of different species known as the first intermediate host of C. sinensis were collected and examined for cercaria infection, and 430 freshwater fishes of different species as the second intermediate host were examined for metacercaria infection. Among 1,473 people examined, 70 (4.75%) were found infected with C. sinensis. By counting eggs per gram feces (EPG), it was found that the intensity of infection in males was stronger than that of females, and the average EPG was 41.87 in all population. Snails, 1.15%, were infected with cercariae of C. sinensis. The average infection rate of freshwater fishes of 15 species with metacercariae of C. sinensis was 16.97%, and the carps reached the highest infection rate (40.74%). A questionnaire was designed with 12 questions covering socioeconomic conditions and human behavior, contamination of the environment, and fishponds. Of 1,473 interviewees, 54% did not know about fluke disease or its transmission route, 12% of those who knew about the fluke believed that the infection causes no harm or only slight harm to their health. Of the interviewees, 27%, ate raw fish at least one to two times per month. Of families, 5% used the same utensils for both raw fish and cooked food. Of the fishpond owners, 40% fed their fishes with feces of domestic animals and humans. All these factors of unhealthy behaviors, poor knowledge, inappropriate farming/fishery practices, and eating raw fish have made the prevalence of clonorchiasis increase in humans in the Shenzhen area. It is urgent to perform a control program, including health education

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

    Directory of Open Access Journals (Sweden)

    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%.

  16. 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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  19. A circular analysis of chronobiology of Schistosoma japonicum cercarial emergence from hilly areas of Anhui, China.

    Science.gov (United States)

    Su, Jing; Zhou, Feng; Lu, Da-Bing

    2013-10-01

    About 46 mammal species have been suspected as reservoir hosts for Schistosoma japonicum and therefore the track of the target parasites, in relation to definitive host species, may be of great importance in terms of theoretical and practical implications. The circadian rhythm of cercariae emergence, a genetically controlled behavior for parasites to adapt to their definitive hosts, may seem to be a perfect biological marker for S. japonicum. In this study, a late (or nocturnal) cercarial emergence pattern was observed on the parasites from one hilly region in Anhui of China, where rodents serve as reservoirs, and on the first generation of the parasites. Moreover, by using the circular statistics, the homogeneity of parasites in such trait was also demonstrated. All these provide evidence for the genetically controlled biological trait, which seems essential in the investigation of macro- or micro-dynamics of parasite transmission of interest. This is particularly true in the case of S. japonicum when multiple parasite isolates or strains are more likely to exist.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. New locality record for Haplorchoides mehrai and possible interactions with Opisthorchis viverrini metacercariae in cyprinid fishes in Northeast Thailand.

    Science.gov (United States)

    Manpratum, Yupin; Kaewkes, Wanlop; Echaubard, Pierre; Sripa, Banchob; Kaewkes, Sasithorn

    2017-02-01

    Metacercariae of Opisthorchis viverrini, a carcinogenic liver fluke, and Haplorchoides sp., a trematode maturing in catfish, are commonly found in cyprinid fish, the second intermediate hosts of both flukes. However, the specific identity of Haplorchoides sp. in Thailand and a precise assessment of the effects of co-infections with O. viverrini have never been clarified. Therefore, we aimed to identify the species of Haplorchoides and to investigate possible interactions of the two trematode species in cyprinid fishes. Based on the morphology and morphometry of the cercaria, metacercaria, and adult stages, the Haplorchoides species found was identified as Haplorchoides mehrai Pande and Shukla 1976. Thailand is formally recorded as a new locality for H. mehrai, where naturally infected hosts include the snail Melanoides tuberculata (first intermediate host), the cyprinid fishes Hampala dispar, Cyclocheilichthys apogon, Puntius leiacanthus, Labiobarbus burmanicus, and Cirrhina jullieni (second intermediate hosts), and a catfish, Mystus nemurus (definitive host). The co-infection rates of O. viverrini and H. mehrai were significantly associated with fish species and fish body region (P < 0.001), with an overall significantly higher average intensity of H. mehrai (126.26 metacercariae/fish) than that of O. viverrini (18.02 metacercariae/fish). Further work is required to demonstrate the extent and mechanisms of possible interactions between these trematode species in the fish host. These data may provide a better understanding of O. viverrini transmission dynamics, and help design integrated control interventions.

  3. Cloning and characterization of SmZF1, a gene encoding a Schistosoma mansoni zinc finger protein

    Directory of Open Access Journals (Sweden)

    Souza Paulo R Eleutério de

    2001-01-01

    Full Text Available The zinc finger motifs (Cys2His2 are found in several proteins playing a role in the regulation of transcripton. SmZF1, a Schistosoma mansoni gene encoding a zinc finger protein was initially isolated from an adult worm cDNA library, as a partial cDNA. The full sequence of the gene was obtained by subcloning and sequencing cDNA and genomic fragments. The collated gene sequence is 2181 nt and the complete cDNA sequence is 705 bp containing the full open reading frame of the gene. Analysis of the genome sequence revealed the presence of three introns interrupting the coding region. The open reading frame theoretically encodes a protein of 164 amino acids, with a calculated molecular mass of 18,667Da. The predicted protein contains three zinc finger motifs, usually present in transcription regulatory proteins. PCR amplification with specific primers for the gene allowed for the detection of the target in egg, cercariae, schistosomulum and adult worm cDNA libraries indicating the expression of the mRNA in these life cycle stages of S. mansoni. This pattern of expression suggests the gene plays a role in vital functions of different life cycle stages of the parasite. Future research will be directed to elucidate the functional role of SmZF1.

  4. 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.

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

    Science.gov (United States)

    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.

  6. 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.

  7. [Environmental and social determinants in schistosomiasis mansoni in Ravena, Minas Gerais, Brazil].

    Science.gov (United States)

    Coura-Filho, P; Farah, M W; Rezende, D F; Lamartine, S S; Carvalho, O S; Katz, N

    1995-01-01

    This study identified the role of biological and social determinants in the transmission of schistosomiasis mansoni in Ravena, Minas Gerais, Brazil, in 1980. This data was used to characterize the clinical and epidemiological profiles of the endemic desease in the population, allowing for the determination of the efficacy of the potable water supply and the specific treatment of those infected with S. mansoni. The district contains three locations, Ravenopolis, Ravena and Lavapes, where the prevalence of the endemic disease was, 20.1%, 42.6% and 63.9%, respectively. The prevalence in the district was statistically higher in men. The age brackets that displayed differences by gender were 10-14 and 15-19 years. Severity of infection was statistically different among individuals within the 10-14 year bracket in ali three locations, and in the 15-19 year bracket among individuals from Ravenopolis and Ravena. The hepatointestinal form was associated with age, and individuals under 15 years of age presented risk of infection 8.85 times higher than adults. Multivariable analysis of the factors involved in transmission of the disease showed that Lavapes was independently associated with infection. In that area, poor sanitary conditions and the proximity of houses to streams infested with S. marsoni cercariae facilitated infection of neighborhood women while performing domestic activities, as well as men digging sand from the streams for construction. These results show the focal nature of transmission of the endemic requiring specific intervention for effective control of disease.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. [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.

  10. Cell types and structures involved in tench, Tinca tinca (L.), defence mechanisms against a systemic digenean infection.

    Science.gov (United States)

    Dezfuli, B S; Lui, A; Pironi, F; Manera, M; Shinn, A P; Lorenzoni, M

    2013-06-01

    Histopathological and ultrastructural investigations were conducted on 36 tench, Tinca tinca (L.), from Lake Trasimeno (Italy). The gills, intestine, liver, spleen, kidney and heart of 21 individuals were found to harbour an extensive infection of larvae of an unidentified digenean trematode. The eyes, gonads, swim bladder and muscles were uninfected. The parasites in each tissue type were embedded in a granulomatous proliferation of tissue, forming a reactive fibroconnective capsule around each larva. Most of the encysted larvae were metacercariae, in a degenerative state, but on occasion some cercariae were found. Many of the granulomas were either necrotic or had a calcified core. Within the granuloma of each, the occurrence of granulocytes, macrophages, rodlet cells and pigment-bearing macrophage aggregates was observed. Hearts bore the highest parasitic infection. Whilst the presence of metacercariae within the intestine was found positioned between the submucosa and muscle layers, metacercariae in the liver were commonly found encysted on its surface where the hepatocytes in close contact with the granuloma were observed to have electron-lucent vesicles within their cytoplasm. Metacercariae encysting adjacent to the cartilaginous rods of gill filaments were seen to elicit a proliferation of the cartilage from the perichondrium. Rodlet cells, neutrophils and mast cells were frequently observed in close proximity to, and within, infected gill capillaries. Given the degenerated state of most granulomas, a morphology-based identification of the enclosed digeneans was not possible.

  11. Non-indigenous benthic fishes as new hosts for Bucephalus polymorphus Baer, 1827 (Digenea: Bucephalidae in the Vistula River basin, Poland

    Directory of Open Access Journals (Sweden)

    Kvach Y.

    2011-02-01

    Full Text Available Two Ponto-Caspian gobiid species, the racer goby, Babka gymnotrachelus, and the monkey goby, Neogobius fluviatilis, the introduced fishes in the Vistula River, Poland, were found being infected with metacercariae of Bucephalus polymorphus. The encysted larvae were located in muscles and fins of these fish. The adult specimens occurred in the gut of another non-indigenous species, the Chinese sleeper Perccottus glenii. The life cycle of B. polymorphus in the Vistula River drainage includes three non-indigenous components: 1 the zebra mussel Dreissena polymorpha, the source of cercariae; 2 gobiids (the racer and monkey gobies, which are new in this water drainage but could play more important role in the life cycle than habitual cyprinids, thanks to their small size (favorable in transmission through the food-web; 3 the Chinese sleeper, a new accidental definitive host. The presence of these non-indigenous components in the life cycle maintains the distribution and further spread of B. polymorphus in the colonized area.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Current status of fasciolosis in Vietnam: an update and perspectives.

    Science.gov (United States)

    Bui, T D; Doanh, P N; Saegerman, C; Losson, B

    2016-09-01

    Vietnam is recognized to be endemic for fasciolosis. However, most of the available publications have not been published in international journals. This review is based on national and international Vietnamese publications and highlights the current status of fasciolosis in Vietnam. It also provides some information available for neighbouring countries. Updated data on responsible species, distribution, transmission and control aspects are summarized. The central region of Vietnam is reported as being highly endemic for fasciolosis, with a high number of human patients (more than 20,000 in 2011). Fasciola gigantica is reported to be the main species in Vietnam. However, hybrids between F. gigantica and F. hepatica were identified. Both humans and animals are infected by the ingestion of raw vegetables and possibly contaminated drinking water. Three lymnaeid snail species (Austropeplea viridis, Radix auricularia and Radix rubiginosa) may act as intermediate hosts of Fasciola spp. However, due to the likely misidentification of snail species and cercariae during the past decade the critical analysis of published data is difficult. A better understanding of transmission aspects of fasciolosis would allow the implementation of preventive measures of this important neglected zoonotic disease.

  14. 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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Chemotherapy-based control of schistosomiasis haematobia. 3. Snail studies monitoring the effect of chemotherapy on transmission in the Msambweni area, Kenya.

    Science.gov (United States)

    Sturrock, R F; Kinyanjui, H; Thíongo, F W; Tosha, S; Ouma, J H; King, C H; Koech, D; Siongok, T K; Mahmoud, A A

    1990-01-01

    Regular snail sampling was performed at 40 sites, representing the principal snail habitats, during a 4 year chemotherapy programme targetted at school-children in the Msambweni area of the coastal plain of Kenya. Populations of Bulinus africanus group snails, primarily from pools, showed seasonal variations, dropping when sites dried out and rising when they were refilled by the rains. Transmission, judged by the recovery of snails shedding typical fucocercous cercariae, continued throughout the treatment period at very low levels (less than 1% of the snails collected were infected) with peaks in October/November and in January/February after seasonal rains. Spatially, most infected snails were recovered from 2 large pools near the sea, close to the school that responded least well to the initial chemotherapy programme. Later, infected snails were found sporadically in inland pools, rice fields and temporary streams near another school where there was evidence of substantial reinfection as the study progressed. The snail findings are consistent with a reduction but not elimination of transmission associated with the chemotherapy programme.

  19. [Demonstration of life cycle with four obligatory hosts of the Hemiurid Trematodes].

    Science.gov (United States)

    Kechemir, N

    1978-01-01

    Research on the transmission of Hemiurid Trematode Halipegus ovocaudatus in experimental and natural conditions demonstrates the following: --the miracidium grows into a sporocyst producing rediae in the Mollusc Planorbis planorbis; -- the cystophorous cercariae become mesocercariae in the hemocoele of Copepodes or finally Ostracodes when swallowed; -- the mesocercariae become matacercariae in the mesenteron of larval Odonates (Zygoptera and Anisoptera) when these larvae swallow the Crustacea; -- the metacercariae become become adults in the Amphibial Rana ridibundal perezi which feeds on dragonflies. The four hosts (Mollusc -- Crustacean -- Odonat -- Amphibian) are obligatory in the life cycle for it is impossible to infect the Insects directly with the cecariae or the frog (tadpoles as well as adults) with the mesocercariae. The different stages of the life cycle of H. oveocaudatus aredescribed and the mode of the transmission is compared with the other species of Halipegus and with the Trematodes in general. The adaptative value of the lengthening of the cycle is discussed from the point of view of the conquest of terrestrial hosts by the Hemiurid Trematodes.

  20. WRECKING THE CURVE: ALTERED FUNCTIONAL RESPONSE OF TETRAGONEURIA (ODONATA: CORDULIIDAE) NAIADS INFECTED WITH METACERCARIAE OF HAEMATOLOECHUS FLOEDAE.

    Science.gov (United States)

    Leaphart, James C; Zelmer, Derek A

    2017-01-24

    The ubiquity of host-parasite interactions and their potential for substantial representation, in terms of overall biomass, within ecosystems suggests that parasites have the capacity to influence energy flow within an ecosystem. While the influence of certain parasites on prey behavior has been well-documented, parasites could also exert an influence on ecosystem dynamics by influencing predator feeding behavior. The functional response of Tetragoneuria naiads was characterized by presenting naiads with varying abundances of Daphnia magna, after which a subset of the naiads were exposed to cercariae of Haematoloechus floedae, and the feeding trials repeated for both the control and exposed odonates. A type II functional response was chosen as an appropriate model for comparison. An indicator variable approach to nonlinear regression of the functional response data indicated that infected odonate naiads spent significantly more time foraging than they did prior to infection, whereas there was no significant change in the functional response of the control naiads. Infected odonates also had a slower rate of growth. These results imply a metabolic cost to infection of Tetragoneuria naiads by H. floedae that might is associated with the encapsulating response to the metacercariae that was observed in infected naiads.

  1. 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.

  2. Digenean parasites of the marine gastropods Littorina littorea and Gibbula umbilicalis in the Northern Portuguese Atlantic coast, with a review of digeneans infecting the two gastropod genera

    Directory of Open Access Journals (Sweden)

    Graça Costa

    2016-05-01

    Full Text Available Objective: To study the digenean parasites of the prosobranch gastropods, Littorina littorea (L. littorea and Gibbula umbilicalis (G. umbilicalis from rocky shores of the Northern Atlantic coast of Portugal. Methods: A total of 413 L. littorea and 2603 G. 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 of L. 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 and Lecithochirium furcolabiatum with a combined prevalence of 3%. Histological observations of gonads of L. littorea revealed 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 adds G. umbilicalis as another first intermediate host for Cainocreadium labracis and extends its geographical range to the Portuguese Atlantic coast. Cercariae of Lecithochirium furcolabiatum were previously reported from G. umbilicalis. A literature review of digeneans occurring in the gastropod genera Gibbula and Littorina is given.

  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. Functional visualization of the excretory system of adult Schistosoma mansoni by the fluorescent marker resorufin.

    Science.gov (United States)

    Sato, H; Kusel, J R; Thornhill, J

    2002-12-01

    Excretion of metabolic wastes as well as xenobiotics is a major concern of all living organisms, and the Platyhelminthes including Schistosoma mansoni possess the protonephridial excretory system for their survival. Except for some ultra-structural and biochemical information, little is known about the protonephridium of platyhelminths due to a lack of established techniques for exploring the excretory activity. This study describes a new technique to assess the excretory activity of S. mansoni by use of the fluorescent marker resorufin, which is a potential substrate of the drug efflux pump, P-glycoprotein. After simple diffusion into the schistosome body, fluorescent resorufin was concentrated in the excretory tubules by an energy-dependent mechanism and excreted via the nephridiopore. The present technique of labelling functionally the excretory system was applicable to adult worms, but not schistosomula or cercariae. A variety of modulators known to interfere with mammalian P-glycoprotein function perturbed resorufin excretion from male adult schistosomes, including cyclosporin A, Ro11-2933, verapamil, or nifedipine. This technique of labelling the excretory system with fluorescent resorufin has enabled us to study aspects of the physiological function, hitherto unknown, of the protonephridial system of S. mansoni.

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

    Science.gov (United States)

    Kusel, J R; Oliveira, F A; Todd, M; Ronketti, F; Lima, S F; Mattos, A C A; Reis, K T; Coelho, P M Z; Thornhill, J A; Ribeiro, F

    2006-09-01

    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.

  6. An ultrastructural study of the cercarial excretory system in Bucephaloides gracilescens and Prosorhynchus squamatus.

    Science.gov (United States)

    Podvyaznaya, I M; Galaktionov, K V

    2004-06-01

    The ultrastructure of the flame cells, capillaries, collecting tubes, excretory bladder, excretory atrium, caudal vesicle, lateral caudal ducts and excretory pores of cercariae of Bucephaloides gracilescens (Rudolphi, 1819) Hopkins, 1954 and Prosorhynchus squamatus Odhner, 1905 (Digenea: Bucephalidae) is described. Both species are essentially similar except for some details. The terminal parts of the protonephridia have all the structural features that are typical of trematodes. The collecting tubes in the cercarial body are composed of cells that are wrapped around the lumen. The main collecting tubes are joined to the excretory bladder syncytium by septate junctions. Features of P. squamatus excretory bladder epithelium indicate that it is involved in secretory activity, but this is not the case in B. gracilescens. In both species the luminal surface of the excretory bladder epithelium is increased by lamellae, and the basal plasma membrane forms invaginations. In the bladder syncytium of P. squamatus both apical lamellae and basal invaginations are more developed and mitochondria are also more numerous. The excretory atrium is lined by a syncytium with nucleated cytons located in the surrounding parenchyma. The atrium lining is not continuous with the body tegument and possesses specific secretory inclusions and a thick glycocalyx. Septate junctions connect the atrium syncytium to the excretory bladder epithelium at its anterior end and to the syncytial excretory epithelium lining the caudal vesicle and the lateral caudal ducts at its posterior. In the excretory pores the caudal duct syncytium is joined to the tegument by septate desmosomes.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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

  10. 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

    Directory of Open Access Journals (Sweden)

    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.

  11. Use of /sup 75/Se tracer and autoradiographic techniques in the study of schistosomiasis

    Energy Technology Data Exchange (ETDEWEB)

    Chandiwana, S.K. (New York State Veterinary Coll., Ithaca, NY (USA))

    1988-12-01

    The paper provides an overview of recent studies on the use of /sup 75/Se to tag larval schistosomes and to monitor their migration and distribution patterns in naive mice and those previously exposed to cercariae. The principles and techniques of radioassay and autoradiography in studying various aspects of /sup 75/Se-labelled larval schistosomes are described. The main shortcoming of radioassay in monitoring location and movement of labelled schistosomula is that some of the label dissociates from the schistosomula and accumulates in host tissues, notably the liver. Dissociated label is indistinguishable from schistosomula-bound label making monitoring of parasite migration extremely difficult. This difficulty is overcome by compressed tissue autoradiography where labelled schistosomula can be seen as reduced silver foci on an autoradiographic film, whereas dissociated label is too diffusely distributed to produce such reduced silver foci. Furthermore, using autoradiography, quantitative information on parasite migration in normal and immunized laboratory animals can be obtained that would be impossible using traditional recovery techniques. In addition to using /sup 75/Se tracer in migration studies, the radio-isotope has potential for elucidating various aspects of schistosome transmission ecology and snail population dynamics in natural waters. (author).

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

    Directory of Open Access Journals (Sweden)

    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

  13. Four marine digenean parasites of Austrolittorina spp. (Gastropoda: Littorinidae) in New Zealand: morphological and molecular data.

    Science.gov (United States)

    O'Dwyer, Katie; Blasco-Costa, Isabel; Poulin, Robert; Faltýnková, Anna

    2014-10-01

    Littorinid snails are one particular group of gastropods identified as important intermediate hosts for a wide range of digenean parasite species, at least throughout the Northern Hemisphere. However nothing is known of trematode species infecting these snails in the Southern Hemisphere. This study is the first attempt at cataloguing the digenean parasites infecting littorinids in New Zealand. Examination of over 5,000 individuals of two species of the genus Austrolittorina Rosewater, A. cincta Quoy & Gaimard and A. antipodum Philippi, from intertidal rocky shores, revealed infections with four digenean species representative of a diverse range of families: Philophthalmidae Looss, 1899, Notocotylidae Lühe, 1909, Renicolidae Dollfus, 1939 and Microphallidae Ward, 1901. This paper provides detailed morphological descriptions of the cercariae and intramolluscan stages of these parasites. Furthermore, partial sequences of the 28S rRNA gene and the mitochondrial gene cytochrome c oxidase subunit 1 (cox1) for varying numbers of isolates of each species were obtained. Phylogenetic analyses were carried out at the superfamily level and along with the morphological data were used to infer the generic affiliation of the species.

  14. Aristolochia gehrtiiinhibits liver toxicity and apoptosis inSchistosoma malayensis infection

    Institute of Scientific and Technical Information of China (English)

    Khaled M M Koriem; Razmy E Shahabudin; Rafiq Z Jamaludin

    2014-01-01

    Objective:To evaluate a protective effect ofAristolochia gehrtii(A. gehrtii) leaves to inhibit liver toxicity and apoptosis inSchistosoma malayensis(S. malayensis) infection.Methods:Forty male albino mice were divided into four equal groups: group1 control including non-infected healthy mice and groups2,3 &4 subcutaneously infected withS. malayensis cercariae where groups3 &4 pretreated withA. gehrtii leaves(200 mg/kg, bwt) & cinnamoylamide(250 mg/kg, bwt), respectively.Results:S. malayensis caused a significant increase in serumAST, ALT,ALP,MDA,NO, bilirubin, urea, creatinine, total cholesterol,LDL, triglycerides, andHDL levels.The pretreatment ofA. gehrtii leaves and cinnamoylamide significantly inhibited that increase.On the other hand,S. malayensis induced a significant decrease in serum total protein, albumin, globulin, albumin/globulin ratio, bloodSOD andGPx, whileA. gehrtii leaves and cinnamoylamide pretreatment increased the above parameters.Treatment withA. gehrtii leaves and cinnamoylamide toS. malayensis infected mice increased p53 expression but decreased bcl-2 expression.These results were supported by histopathological investigations.Conclusions:A. gehrtii inhibits liver toxicity and apoptosis inS. malayensis infection and this effect is associated with the major cinnamoylamide ingredient ofA. gehrtii leaves.

  15. High fat diet has a prominent effect upon the course of chronic schistosomiasis mansoni in mice

    Directory of Open Access Journals (Sweden)

    Alba Cristina Miranda de Barros Alencar

    2009-07-01

    Full Text Available This study investigated whether a long-term high-fat diet has an effect on the outcome of chronic murine schistosomiasis mansoni compared to a standard diet. Swiss Webster female mice (3 weeks old were fed each diet for up to six months and were then infected with 50 Schistosoma mansoni cercariae. Their nutritional status was assessed by monitoring total serum cholesterol and body mass. Infected mice were examined 6-17 weeks post infection to estimate the number of eggs in faeces. Mice were euthanised the next day. Total serum cholesterol was lower in infected mice in comparison to uninfected controls (p = 0.0055. In contrast, body mass (p = 0.003, liver volume (p = 0.0405, spleen volume (p = 0.0124, lung volume (p = 0.0033 and faecal (p = 0.0064 and tissue egg density (p = 0.0002 were significantly higher for infected mice fed a high-fat diet. From these findings, it is suggested that a high-fat diet has a prominent effect on the course of chronic schistosomiasis mansoni in mice.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. New Perspectives on Host-Parasite Interplay by Comparative Transcriptomic and Proteomic Analyses of Schistosoma japonicum.

    Directory of Open Access Journals (Sweden)

    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.

  18. Schistosomiasis: Water Contact Pattern and Snail Infection Rates in Opa Reservoir and Research Farm Ponds in Obafemi Awolowo University, Ile-Ife, Nigeria

    Directory of Open Access Journals (Sweden)

    I.E. Ofoezie

    2006-01-01

    Full Text Available Human water contact pattern and Schistosoma infection rates in snails were studied in Opa Reservoir and Research Farm Ponds in Obafemi Awolowo University campus for a 12 month period covering both seasons of the annual cycle. This is with a view to know the water contact pattern and relate this to the potential for schistosomiasis transmission in the water bodies. Generally, water contact activities were more diverse and longer in the reservoir than in the ponds. Seasonal and daily variations were pronounced with water contact being most intense in the rainy season and in the early hours of the day till about noon. The water contact behavior in this area were quite age and sex related. The frequency and duration of contacts made by males were significantly higher than those of females (pSchistosoma showed that no infected snail was found in the ponds but infected snails were found in the reservoir in a site, S3, in November and December, 2002. Water contact pattern in this study was site specific with 76.1% of the total contacts made at the site where human Schistosoma type cercariae were also found. The implications are discussed.

  19. Optimization of Conditions for In Vitro Culture of the Microphallid Digenean Gynaecotyla adunca.

    Science.gov (United States)

    West, Jenna; Mitchell, Alexandra; Pung, Oscar J

    2014-01-01

    In vitro cultivation of digeneans would aid the development of effective treatments and studies of the biology of the parasites. The goal of this study was to optimize culture conditions for the trematode, Gynaecotyla adunca. Metacercariae of the parasite from fiddler crabs, Uca pugnax, excysted in trypsin, were incubated overnight to permit fertilization, and were cultured in different conditions to find those that resulted in maximum worm longevity and egg production. When cultured in media lacking serum, worms lived longer in Hanks balanced salt solution and Dulbecco's Modified Eagle medium/F-12 (DME/F-12) than in RPMI-1640 but produced the most eggs in DME/F-12. Worm longevity and egg production increased when worms were grown in DME/F-12 supplemented with 20% chicken, horse, or newborn calf serum but the greatest number of eggs was deposited in cultures containing horse or chicken serum. Horse serum was chosen over chicken serum due to the formation of a precipitate in chicken serum. The optimal concentration of horse serum with respect to egg production ranged from 5 to 20%. Infectivity of eggs deposited by worms in culture was tested by feeding eggs to mud snails, Ilyanassa obsoleta. None of these snails produced G. adunca cercariae.

  20. Optimization of Conditions for In Vitro Culture of the Microphallid Digenean Gynaecotyla adunca

    Directory of Open Access Journals (Sweden)

    Jenna West

    2014-01-01

    Full Text Available In vitro cultivation of digeneans would aid the development of effective treatments and studies of the biology of the parasites. The goal of this study was to optimize culture conditions for the trematode, Gynaecotyla adunca. Metacercariae of the parasite from fiddler crabs, Uca pugnax, excysted in trypsin, were incubated overnight to permit fertilization, and were cultured in different conditions to find those that resulted in maximum worm longevity and egg production. When cultured in media lacking serum, worms lived longer in Hanks balanced salt solution and Dulbecco’s Modified Eagle medium/F-12 (DME/F-12 than in RPMI-1640 but produced the most eggs in DME/F-12. Worm longevity and egg production increased when worms were grown in DME/F-12 supplemented with 20% chicken, horse, or newborn calf serum but the greatest number of eggs was deposited in cultures containing horse or chicken serum. Horse serum was chosen over chicken serum due to the formation of a precipitate in chicken serum. The optimal concentration of horse serum with respect to egg production ranged from 5 to 20%. Infectivity of eggs deposited by worms in culture was tested by feeding eggs to mud snails, Ilyanassa obsoleta. None of these snails produced G. adunca cercariae.

  1. 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.

  2. 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.

  3. Changes in the small intestine of Schistosoma mansoni-infected mice fed a high-fat diet.

    Science.gov (United States)

    Alencar, Alba Cristina Miranda de Barros; Neves, Renata Heisler; de Oliveira, Albanita Viana; Machado-Silva, José Roberto

    2012-05-01

    The consumption of a high-fat diet modifies both the morphology of the small intestine and experimentally tested effects of schistosomiasis mansoni. However, whether a schistosomiasis infection associated with a high-fat diet causes injury to the small intestine has never been investigated. Mice were fed either a high-fat or a standard-fat diet for 6 months and were then infected with Schistosoma mansoni cercariae. Physical characteristics of the intestinal tissue (mucosal thickness, small intestinal villi length and height, and abundance of goblet cells and enterocytes on the villous surface) and the distribution of granulomas along the intestinal segments and their developmental stage were measured at the time of sacrifice (9 or 17 weeks post-infection). The group fed a high-fat diet exhibited different granuloma stages, whereas the control group possessed only exudative granulomas. The chronically infected mice fed a high-fat diet exhibited higher granuloma and egg numbers than the acutely infected group. Exudative, exudative/exudative-productive and exudative-productive granulomas were present irrespective of diet. Computer-aided morphometric analysis confirmed that villus length, villus width, muscular height and submucosal height of the duodenal and jejunal segments were affected by diet and infection. In conclusion, a high-fat diet and infection had a significant impact on the small intestine morphology and morphometry among the animals tested.

  4. Impact of Climate Variability on Prevalence of Urinary Schistosomiasis over Sunyani in the Transition Belt of Ghana

    Science.gov (United States)

    Tay, S. K.; Amekudzi, L. K.; Tagoe, G.

    2012-04-01

    A study has been conducted to determine the impact of climate variability on Schistosoma haematobium infection among patients and school children in Sunyani between 2006 and 2009. Urine samples from the subjects were collected and examined in the laboratory using the filtration technique for the detection and quantification of Schistosomiasis haematobium eggs. The prevalence rate of urinary schistosomiasis at the Sunyani Regional Hospital for 2006, 2007, 2008 and 2009 were found to be 0.24%, 0.55%, 0.55% and 0.75% respectively while that for Methodist Junior High School in 2008 and 2009 were 60.1% and 60.3% respectively. A decrease in the relative humidity and average annual rainfall were identified as factors contributory to the increase in urinary Schistosomiasis prevalence rate. The temperature values obtained throughout the study period did not have any significant effect on the prevalence rate. The temperature values, however, were those that enhanced cercarial incubation (15-35˚C) with a resultant increase in shedding of cercariae leading to more infections among water contacts. The infection rate due to stream Amama was 20.1%, while that due to river Tano was 36.6%. The highest risk group was children aged 15-19 years. Praziquantel was administered to treat the infection, producing a cure rate of 93%. Recognition of urinary Schistosomiasis as a public health problem in Ghana is the main challenge to prevention and control of the disease.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Susceptibility of Some Wild Rodents Widely Distributed in Egyptian Foci to Schistosoma mansoni Infection under Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Ismail M. Al-Sharkawi

    2011-01-01

    Full Text Available The most important definitive host of Schistosoma mansoni is the human, however, numerous other mammalian species were found to be infected with this parasite. Among these species, the wild rodents are the most common. In this study, the susceptibility of some wild rodents widely distributed in Egypt to S. mansoni infection was evaluated. Five wild species were tested for the susceptibility of S. mansoni infection in vitro; including Mus musculus (black mice, Acomys cahirinus (Cairo spiny mice, Rattus rattus (house rats, Rattus norvegilcus (Norway rats, Rattus norvegicus (albino rats and Arvicanthis niloticus (Nile rats. Laboratory mice were used as a positive control. Rodents were infected individually with 150 S. mansoni cercariae by tail immersion and housed for 8 week post-infection. The results reported that the Nile rats showed the highest number of worm burden (90 worms, while the Norway rats and the laboratory rats showed the lowest numbers among the tested species. This study also showed that the Nile rats, the house rats and the Norway rats yielded high number of eggs in the liver tissues. In contrast, the Cairo spiny mice, the black mice and albino rats yielded low number of eggs in the liver tissue. As compared to the permissive host albino mice, the Nile rats, the black mice, the Cairo spiny mice and the house rats showed comparable granuloma size. In contrast, albino rats and Norway rats showed a small granuloma size. Alltogether, these data showed that S. mansoni infection to these wild rodents was species dependant.

  7. Effects of garlic on Schistosoma mansoni harbored in albino mice: molecular characterization of the host and parasite.

    Science.gov (United States)

    Riad, Nahed H A; Taha, Hoda A; Mahmoud, Yomna I

    2013-04-15

    Garlic has been used for its health benefits for thousands of years. Modern research confirmed many of the healing properties of garlic, including its antiparasitic activity. This study was designed to evaluate the antischistosomal action of garlic through detecting the changes in DNA profile of Schistosoma mansoni worms and the infected mouse. Forty mice were subcutaneously infected with ~200 Schistosoma mansoni cercariae/mouse. Infected mice were divided into four equal groups: non-treated, prophylactic, therapeutic, and continuously-treated. Non-infected control and garlic-treated groups were assigned for the sake of comparison. Garlic extract (50mg/kg bw/mouse) was given orally, day after day, at a fixed daytime. Seven weeks post-infection, adult schistosomes were recovered by perfusion and the livers of the mice were excised out and were processed for DNA extraction and Random Amplification of Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR). The results showed that garlic exerted no major changes in the genome of schistosomes. Nevertheless, that schistosomal infection induced genetic alterations in the DNA of mice, and garlic was able to ameliorate such alterations to a great extent.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. 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.

  10. On the origin of the Biomphalaria glabrata hemocytes

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Taken to the limit--Is desiccation stress causing precocious encystment of trematode parasites in snails?

    Science.gov (United States)

    O'Dwyer, Katie; Poulin, Robert

    2015-12-01

    When hosts experience environmental stress, the quantity and quality of resources they provide for parasites may be diminished, and host longevity may be decreased. Under stress, parasites may adopt alternative strategies to avoid fitness reductions. Trematode parasites typically have complex life cycles, involving asexual reproduction in a gastropod first intermediate host. A rare phenomenon, briefly mentioned in the literature, and termed 'precocious encystment' involves the next stage in the parasites' life cycle (metacercarial cyst) forming within the preceding stage (redia), while still inside the snail. In the trematode Parorchis sp. NZ using rocky shore snails exposed to long periods outside water, we hypothesised that this might be an adaptive strategy against desiccation, preventing parasite emergence from the snail. To test this, we first investigated the effect of prolonged desiccation on the survival of two species of high intertidal snails. Secondly, we measured the reproductive output (cercarial production) of the parasite under wet and dry conditions. Finally, we quantified the influence of desiccation stress on the occurrence of precocious encystment. Snail mortality was higher under dry conditions, indicating stress, and it was somewhat exacerbated for infected snails. Parasite reproductive output differed between wet and dry conditions, with parasites of snails kept in dry conditions producing more cercariae when placed in water. Little variation was observed in the occurrence of precocious encystment, although some subtle patterns emerged. Given the stresses associated with living in high intertidal environments, we discuss precocious encystment as a possible stress response in this trematode parasite.

  13. 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.

  14. Viability of developmental stages of Schistosoma mansoni quantified with xCELLigence worm real-time motility assay (xWORM).

    Science.gov (United States)

    Rinaldi, Gabriel; Loukas, Alex; Brindley, Paul J; Irelan, Jeff T; Smout, Michael J

    2015-12-01

    Infection with helminth parasites causes morbidity and mortality in billions of people and livestock worldwide. Where anthelmintic drugs are available, drug resistance is a major problem in livestock parasites, and a looming threat to public health. Monitoring the efficacy of these medicines and screening for new drugs has been hindered by the lack of objective, high-throughput approaches. Several cell monitoring technologies have been adapted for parasitic worms, including video-, fluorescence-, metabolism enzyme- and impedance-based tools that minimize the screening bottleneck. Using the xCELLigence impedance-based system we previously developed a motility-viability assay that is applicable for a range of helminth parasites. Here we have improved substantially the assay by using diverse frequency settings, and have named it the xCELLigence worm real-time motility assay (xWORM). By utilizing strictly standardized mean difference analysis we compared the xWORM output measured with 10, 25 and 50 kHz frequencies to quantify the motility of schistosome adults (human blood flukes) and hatching of schistosome eggs. Furthermore, we have described a novel application of xWORM to monitor movement of schistosome cercariae, the developmental stage that is infectious to humans. For all three stages, 25 kHz was either optimal or near-optimal for monitoring and quantifying schistosome motility. These improvements in methodology sensitivity should enhance the capacity to screen small compound libraries for new drugs both for schistosomes and other helminth pathogens at large.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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.

  17. 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).

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Chronobiology of trematode cercarial emergence: from data recovery to epidemiological, ecological and evolutionary implications.

    Science.gov (United States)

    Théron, André

    2015-04-01

    One major challenge for parasites with complex cycles consists to succeed in the transmission from one host to the next host. To maximize the probability of encountering the right host, numerous trematode species have selected various emergence rhythms occurring during the escape of the short-lived cercariae from the mollusc host. Cercarial shedding patterns are beautiful examples of adaptation of the parasite for a successful rendezvous with its subsequent host. In this review, after an analysis of the technical and statistical aspects specific to such studies, we compile the knowledge and unresolved issues we have about the synchronization of these rhythms, their genetic support and the role of the host physiology or activity. We are also interested on how cercarial rhythmicity influences cercarial densities in waters of transmission sites and then the risk of host infection in case of schistosomiasis. Ecological significance of the inter- and intra-specific diversity of these rhythms is emphasized as well as the evolutionary implication of new chronotypes resulting from the capture of new host species and promoting reproductive isolation and alloxenic speciation. Currently, genome sequence data now available for some trematodes such as the schistosomes provide an unprecedented resource for new research approaches that should contribute identification of the genes and mechanisms involved in determining the cercarial shedding rhythms observed.

  20. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Therapeutic effect of Arctium lappa in Schistosoma haematobium associated kidney disturbance: biochemical and molecular effects.

    Science.gov (United States)

    Koriem, Khaled M M; Idris, Zulzamri H; Haron, Hasniza F; Omar, Nurulhuda A; Lazain, Halita S

    2016-12-01

    Schistosoma haematobium (S. haematobium) infection has been found to be strongly associated with bladder cancer, which necessitates for discover of a natural new therapeutic agent. The aim of this study was to evaluate the therapeutic effect of Arctium lappa seed extract in S. haematobium associated kidney disturbance. Forty male albino mice were used and divided into four equal groups; group 1 control includes non-infected healthy mice, groups 2, 3 and 4 subcutaneous infected with S. haematobium cercariae. Groups 3 co-treated daily with oral dose of A. lappa seed extract (300 mg/kg, bwt) for 15 days in the same time of S. haematobium infection. Groups 4 post-treated daily for 15 days with oral dose of A. lappa seed extract (300 mg/kg, bwt) after 15 days of S. haematobium infection. The results obtained revealed that S. haematobium significantly decreased kidney weight and serum sodium, potassium and chloride, but increased urinary volume, urinary excretion of sodium, potassium and chloride, serum urea, creatinine and uric acid. Schistosoma haematobium also significantly decreased kidney superoxide dismutase, glutathione peroxidase and reduced glutathione levels while increased kidney lipid peroxidation level. Co- and post-treatment with A. lappa seed extract restore all the above parameters to approach the normal values. These results were supported with histopathological examinations. In conclusion, A. lappa seed extract has therapeutic effect in kidney disturbance caused by S. haematobium where co-treatment of A. lappa seed extract was more effective than post-treatment of the extract.

  3. 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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Inhibition of Granulomatous Inflammation and Prophylactic Treatment of Schistosomiasis with a Combination of Edelfosine and Praziquantel.

    Directory of Open Access Journals (Sweden)

    Edward Yepes

    Full Text Available Schistosomiasis is the third most devastating tropical disease worldwide caused by blood flukes of the genus Schistosoma. This parasitic disease is due to immunologic reactions to Schistosoma eggs trapped in tissues. Egg-released antigens stimulate tissue-destructive inflammatory and granulomatous reactions, involving different immune cell populations, including T cells and granulocytes. Granulomas lead to collagen fibers deposition and fibrosis, resulting in organ damage. Praziquantel (PZQ is the drug of choice for treating all species of schistosomes. However, PZQ kills only adult Schistosoma worms, not immature stages. The inability of PZQ to abort early infection or prevent re-infection, and the lack of prophylactic effect prompt the need for novel drugs and strategies for the prevention of schistosomiasis.Using in vitro and in vivo approaches, we have found that the alkylphospholipid analog edelfosine kills schistosomula, and displays anti-inflammatory activity. The combined treatment of PZQ and edelfosine during a few days before and after cercariae infection in a schistosomiasis mouse model, simulating a prophylactic treatment, led to seven major effects: a killing of Schistosoma parasites at early and late development stages; b reduction of hepatomegaly; c granuloma size reduction; d down-regulation of Th1, Th2 and Th17 responses at late post-infection times, thus inhibiting granuloma formation; e upregulation of IL-10 at early post-infection times, thus potentiating anti-inflammatory actions; f down-regulation of IL-10 at late post-infection times, thus favoring resistance to re-infection; g reduction in the number of blood granulocytes in late post-infection times as compared to infected untreated animals.Taken together, these data suggest that the combined treatment of PZQ and edelfosine promotes a high decrease in granuloma formation, as well as in the cellular immune response that underlies granuloma development, with changes in the

  6. 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

  7. 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.

  8. Effect of pond water depth on snail populations and fish-borne zoonotic trematode transmission in juvenile giant gourami (Osphronemus goramy) aquaculture nurseries.

    Science.gov (United States)

    Thien, P C; Madsen, H; Nga, H T N; Dalsgaard, A; Murrell, K D

    2015-12-01

    Infection with fish-borne zoonotic trematodes (FZT) is an important public health problem in many parts of Southeast Asia. People become infected with FZT when eating raw or undercooked fish that contain the infective stage (metacercariae) of FZT. The parasites require specific freshwater snails as first intermediate host and a variety of fish species, both wild caught and cultured, as second intermediate host. Aquaculture production has grown almost exponentially in SE Asia and in order to produce fish free from FZT metacercariae, it is important to mitigate factors promoting transmission to fish. Here we report results from a cross-sectional study to look at the association between pond depth and infection with FZT in giant gourami nursery ponds. Density of intermediate host snails was positively associated with pond depth (count ratio associated with a 1m increase in pond depth was 10.4 (95% C.L.: 1.61-67.1, p200 fry m(-3)) was associated with lower host snail density (count ratio=0.15) than low stocking density (<100 fry m(3)). Ponds stocked with 100-200 fry m(-3) had snail counts 0.76 (95% C.L.: 0.33-1.75, p n.s.) of those in ponds stocked with fry density of <100 fry m(-3). Since density of intermediate snail hosts was associated with FZT transmission to fish, effort should be taken to reduce snail density prior to stocking the fry, but focus should also be on habitats surrounding ponds as transmission may occur through cercariae produced outside ponds and carried into ponds with water pumped into ponds.

  9. 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.

  10. Integrative taxonomy identifies a new species of Phyllodistomum (Digenea: Gorgoderidae) from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), in Central Veracruz, Mexico.

    Science.gov (United States)

    Razo-Mendivil, Ulises; Pérez-Ponce de León, Gerardo; Rubio-Godoy, Miguel

    2013-12-01

    Phyllodistomum inecoli n. sp. is described from the twospot livebearer, Heterandria bimaculata (Teleostei: Poeciliidae), collected in the Río La Antigua basin, Veracruz, Mexico. The new species is described and characterised by using a combination of morphology, scanning electron microscopy, and sequences of nuclear and mitochondrial genes. Diagnostic characters of the new species of Phyllodistomum include a genital pore opening at the level of the caecal bifurcation; oval vitellarium, situated just posterior to the ventral sucker and not extended laterally and anterior extracaecal uterine loops variable in extension (reaching the anterior, median or posterior margin of the ventral sucker). P. inecoli n. sp. most closely resembles P. brevicecum, a species described as a parasite of the central mudminnow, Umbra limi, in other parts of North America; however, the genital pore in P. brevicecum is situated between the caecal bifurcation and the ventral sucker, the ovary is larger, the vitellarium is lobed and extended laterally and the anterior portion of the uterus extends to the posterior margin of the ventral sucker. Comparison of about 1,500–2,200 nucleotides of cox1 and 28S rDNA and ITS1 strongly supports the status of P. inecoli as a new species. Bayesian inference analysis of combined datasets of 28S rDNA and cox1 sequences showed that P. inecoli n. sp. and the other species found in freshwater fishes of Mexico, including the species complex of P. lacustri, are not sister species. Phylogenetic analysis based on 28S rDNA sequences of several gorgoderid taxa revealed the close relationship of P. inecoli n. sp. with several species of Phyllodistomum, Gorgodera and Gorgoderina with cystocercous cercariae developing in sphaeriid bivalves. Dot-plot analysis of ITS1 sequences of P. inecoli n. sp. revealed the presence of eight repetitive elements with different length, which together represent almost half the length of ITS1.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. The role of damselflies (Odonata: Zygoptera) as paratenic hosts in the transmission of Halipegus eccentricus (Digenea: Hemiuridae) to anurans.

    Science.gov (United States)

    Bolek, Matthew G; Tracy, Heather R; Janovy, John

    2010-08-01

    Halipegus eccentricus is a common hemiurid trematode in the eustachian tubes of North America frogs. However, the life cycle of this species has never been completely elucidated. Studies on H. eccentricus suggest that it has a 3-host life cycle. Here, we show through fieldwork and host specificity experimental infections that the life cycle of Halipegus eccentricus utilizes 4 hosts. Metamorphosed anurans become infected with H. eccentricus by feeding on infected damselflies; worms reside in the stomach of anurans, migrate to the eustachian tubes within 32-39 days post-exposure (DPE), and release eggs 50-60 DPE. Cystophorous cercariae develop in Physa gyrina snails within 32-35 DPE, infect ostracod ( Cypridopsis sp.) second intermediate hosts, and develop to metacercariae. Fifteen- to 19-day-old metacercariae from ostracods are infective to both damselfly larvae and metamorphosed anurans. Field surveys of damselflies and tadpoles, along with laboratory exposure of damselfly larvae, metamorphosed anurans, and tadpoles with infected ostracods, indicated that only metamorphosed anurans and damselflies become infected with H. eccentricus , whereas field-collected tadpoles and laboratory-exposed tadpoles were never infected with H. eccentricus . Because little morphological change occurred in the metacercaria stage of H. eccentricus between the ostracod second intermediate host and damselfly host, and metamorphosed anurans became infected with H. eccentricus metacercariae recovered from both host groups, we suggest that odonates serve as paratenic hosts in this life cycle. Additionally, our field work and experimental infections provide data on the use of odonates as the route of infection by another North American Halipegus sp. that matures in the stomach of frogs. Our data indicate that when the life cycles are known, the use of odonates as the route of infection to anurans is common in the life cycles of Halipegus spp., and all species exhibit remarkable infection

  13. 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.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Haemolymph Components of Infected & None Infected Lymnaea Snails with Xiphidiocercariae

    Directory of Open Access Journals (Sweden)

    AA Saboor Yaraghi

    2011-03-01

    Full Text Available Background: In this study the haemolymph components of infected and none infected Lymnaea gedrosiana with xiphidiocercaria larvae was compared.Methods: Five hundred Fifty Lymnaea snails were collected from Ilam and Mazandaran prov­inces, Iran, during 2008-2009. The snails were transported to the lab at Tehran University of Medi­cal Sciences and their cercarial sheddings were studied. Haemolmyphs of snails were ex­tracted and cells were counted using haemocytometer and cell-surface carbohydrate were recog­nized by conjugated lectin (Lentil. Haemolymph protein concentrations were measured by Brad­ford protein assay method and soluble protein compositions were determined on sodium dodecyl sulphate polyacrilamide gel electrophoresis (SDS-PAGE.Result: From the 550 examined Lymnaea snails for cercariae, 27 snails were infected with xiphidiocer­cariae. Mean of haemolymph cells (haemocyte number were obtained 93480±2.43 (cells/ml for none infected snails (25 snail and 124560±2800 (cells/ml for infected snails (25 snail. Mannose carbohydrate was recognized on haemocyte of none infected and infected snails. Mean of protein concentration of haemolymph plasma was obtained as 1354 ± 160 μg/ml (1.4 mg/ml for none infected snails (25 snails and 1802±138 μg/ml (1.8 mg/ml for infected snail (25 snails. Comparing to none infected snails, the SDS-PAGE results of haemolymph plasma of infected snails, showed an extra protein band (70 kDa. The results showed a significant differ­ence between the amounts and the kinds of proteins in haemolymph of infected and none infected snails.Conclusion: This information might be useful to understand of parasite detection, adhesion, engulf­ment and antigen agglutination by snail.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Septins of Platyhelminths: identification, phylogeny, expression and localization among developmental stages of Schistosoma mansoni.

    Science.gov (United States)

    Zeraik, Ana E; Rinaldi, Gabriel; Mann, Victoria H; Popratiloff, Anastas; Araujo, Ana P U; Demarco, Ricardo; Brindley, Paul J

    2013-01-01

    Septins are a family of eukaryotic GTP binding proteins conserved from yeasts to humans. Originally identified in mutants of budding yeast, septins participate in diverse cellular functions including cytokinesis, organization of actin networks, cell polarity, vesicle trafficking and many others. Septins assemble into heteroligomers to form filaments and rings. Here, four septins of Schistosoma mansoni are described, which appear to be conserved within the phylum Platyhelminthes. These orthologues were related to the SEPT5, SEPT10 and SEPT7 septins of humans, and hence we have termed the schistosome septins SmSEPT5, SmSEPT10, SmSEPT7.1 and SmSEPT7.2. Septin transcripts were detected throughout the developmental cycle of the schistosome and a similar expression profile was observed for septins in the stages examined, consistent with concerted production of these proteins to form heterocomplexes. Immunolocalization analyses undertaken with antibodies specific for SmSEPT5 and SmSEPT10 revealed a broad tissue distribution of septins in the schistosomulum and colocalization of septin and actin in the longitudinal and circular muscles of the sporocyst. Ciliated epidermal plates of the miracidium were rich in septins. Expression levels for these septins were elevated in germ cells in the miracidium and sporocyst. Intriguingly, septins colocalize with the protonephridial system of the cercaria, which extends laterally along the length of this larval stage. Together, the findings revealed that schistosomes expressed several septins which likely form filaments within the cells, as in other eukaryotes. Identification and localization demonstrating a broad distribution of septins across organs and tissues of schistosome contributes towards the understanding of septins in schistosomes and other flatworms.

  19. Septins of Platyhelminths: identification, phylogeny, expression and localization among developmental stages of Schistosoma mansoni.

    Directory of Open Access Journals (Sweden)

    Ana E Zeraik

    Full Text Available Septins are a family of eukaryotic GTP binding proteins conserved from yeasts to humans. Originally identified in mutants of budding yeast, septins participate in diverse cellular functions including cytokinesis, organization of actin networks, cell polarity, vesicle trafficking and many others. Septins assemble into heteroligomers to form filaments and rings. Here, four septins of Schistosoma mansoni are described, which appear to be conserved within the phylum Platyhelminthes. These orthologues were related to the SEPT5, SEPT10 and SEPT7 septins of humans, and hence we have termed the schistosome septins SmSEPT5, SmSEPT10, SmSEPT7.1 and SmSEPT7.2. Septin transcripts were detected throughout the developmental cycle of the schistosome and a similar expression profile was observed for septins in the stages examined, consistent with concerted production of these proteins to form heterocomplexes. Immunolocalization analyses undertaken with antibodies specific for SmSEPT5 and SmSEPT10 revealed a broad tissue distribution of septins in the schistosomulum and colocalization of septin and actin in the longitudinal and circular muscles of the sporocyst. Ciliated epidermal plates of the miracidium were rich in septins. Expression levels for these septins were elevated in germ cells in the miracidium and sporocyst. Intriguingly, septins colocalize with the protonephridial system of the cercaria, which extends laterally along the length of this larval stage. Together, the findings revealed that schistosomes expressed several septins which likely form filaments within the cells, as in other eukaryotes. Identification and localization demonstrating a broad distribution of septins across organs and tissues of schistosome contributes towards the understanding of septins in schistosomes and other flatworms.

  20. Fasciola hepatica and lymnaeid snails occurring at very high altitude in South America.

    Science.gov (United States)

    Mas-Coma, S; Funatsu, I R; Bargues, M D

    2001-01-01

    Fascioliasis due to the digenean species Fasciola hepatica has recently proved to be an important public health problem, with human cases reported in countries of the five continents, including severe symptoms and pathology, with singular epidemiological characteristics, and presenting human endemic areas ranging from hypo- to hyperendemic. One of the singular epidemiological characteristics of human fascioliasis is the link of the hyperendemic areas to very high altitude regions, at least in South America. The Northern Bolivian Altiplano, located at very high altitude (3800-4100 m), presents the highest prevalences and intensities of human fascioliasis known. Sequences of the internal transcribed spacers ITS-1 and ITS-2 of the nuclear ribosomal DNA of Altiplanic Fasciola hepatica and the intermediate snail host Lymnaea truncatula suggest that both were recently introduced from Europe. Studies were undertaken to understand how the liver fluke and its lymnaeid snail host adapted to the extreme environmental conditions of the high altitude and succeeded in giving rise to high infection rates. In experimental infections of Altiplanic lymnaeids carried out with liver fluke isolates from Altiplanic sheep and cattle, the following aspects were studied: miracidium development inside the egg, infectivity of miracidia, prepatent period, shedding period, chronobiology of cercarial emergence, number of cercariae shed by individual snails, survival of molluscs at the beginning of the shedding process, survival of infected snails after the end of the shedding period and longevity of shedding and non-shedding snails. When comparing the development characteristics of European F. hepatica and L. truncatula, a longer cercarial shedding period and a higher cercarial production were observed, both aspects related to a greater survival capacity of the infected lymnaeid snails from the Altiplano. These differences would appear to favour transmission and may be interpreted as strategies

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Galectin-3, histone deacetylases, and Hedgehog signaling: Possible convergent targets in schistosomiasis-induced liver fibrosis

    Science.gov (United States)

    de Oliveira, Felipe Leite; Carneiro, Katia; Brito, José Marques; Cabanel, Mariana; Pereira, Jonathas Xavier; Paiva, Ligia de Almeida; Syn, Wingkin; Henderson, Neil C.; El-Cheikh, Marcia Cury

    2017-01-01

    Schistosomiasis affects approximately 240 million people in the world. Schistosoma mansoni eggs in the liver induce periportal fibrosis and hepatic failure driven by monocyte recruitment and macrophage activation, resulting in robust Th2 response. Here, we suggested a possible involvement of Galectin-3 (Gal-3), histone deacetylases (HDACs), and Hedgehog (Hh) signaling with macrophage activation during Th1/Th2 immune responses, fibrogranuloma reaction, and tissue repair during schistosomiasis. Gal-3 is highly expressed by liver macrophages (Kupffer cells) around Schistosoma eggs. HDACs and Hh regulate macrophage polarization and hepatic stellate cell activation during schistosomiasis-associated fibrogenesis. Previously, we demonstrated an abnormal extracellular matrix distribution in the liver that correlated with atypical monocyte–macrophage differentiation in S. mansoni-infected, Gal-3-deficient (Lgals3-/-) mice. New findings explored in this review focus on the chronic phase, when wild-type (Lgals3+/+) and Lgals3-/- mice were analyzed 90 days after cercariae infection. In Lgals3-/- infected mice, there was significant inflammatory infiltration with myeloid cells associated with egg destruction (hematoxylin and eosin staining), phagocytes (specifically Kupffer cells), numerically reduced and diffuse matrix extracellular deposition in fibrotic areas (Gomori trichrome staining), and severe disorganization of collagen fibers surrounding the S. mansoni eggs (reticulin staining). Granuloma-derived stromal cells (GR cells) of Lgals3-/- infected mice expressed lower levels of alpha smooth muscle actin (α-SMA) and eotaxin and higher levels of IL-4 than Lgals3+/+ mice (real-time PCR). The relevant participation of macrophages in these events led us to suggest distinct mechanisms of activation that culminate in defective fibrosis in the liver of Lgals3-/- infected mice. These aspects were discussed in this review, as well as the possible interference between Gal-3, HDACs

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Septins of Platyhelminths: Identification, Phylogeny, Expression and Localization among Developmental Stages of Schistosoma mansoni

    Science.gov (United States)

    Zeraik, Ana E.; Rinaldi, Gabriel; Mann, Victoria H.; Popratiloff, Anastas; Araujo, Ana P. U.; DeMarco, Ricardo; Brindley, Paul J.

    2013-01-01

    Septins are a family of eukaryotic GTP binding proteins conserved from yeasts to humans. Originally identified in mutants of budding yeast, septins participate in diverse cellular functions including cytokinesis, organization of actin networks, cell polarity, vesicle trafficking and many others. Septins assemble into heteroligomers to form filaments and rings. Here, four septins of Schistosoma mansoni are described, which appear to be conserved within the phylum Platyhelminthes. These orthologues were related to the SEPT5, SEPT10 and SEPT7 septins of humans, and hence we have termed the schistosome septins SmSEPT5, SmSEPT10, SmSEPT7.1 and SmSEPT7.2. Septin transcripts were detected throughout the developmental cycle of the schistosome and a similar expression profile was observed for septins in the stages examined, consistent with concerted production of these proteins to form heterocomplexes. Immunolocalization analyses undertaken with antibodies specific for SmSEPT5 and SmSEPT10 revealed a broad tissue distribution of septins in the schistosomulum and colocalization of septin and actin in the longitudinal and circular muscles of the sporocyst. Ciliated epidermal plates of the miracidium were rich in septins. Expression levels for these septins were elevated in germ cells in the miracidium and sporocyst. Intriguingly, septins colocalize with the protonephridial system of the cercaria, which extends laterally along the length of this larval stage. Together, the findings revealed that schistosomes expressed several septins which likely form filaments within the cells, as in other eukaryotes. Identification and localization demonstrating a broad distribution of septins across organs and tissues of schistosome contributes towards the understanding of septins in schistosomes and other flatworms. PMID:24367716

  6. Developmental gene expression profiles of the human pathogen Schistosoma japonicum

    Directory of Open Access Journals (Sweden)

    McManus Donald P

    2009-03-01

    Full Text Available Abstract Background The schistosome blood flukes are complex trematodes and cause a chronic parasitic disease of significant public health importance worldwide, schistosomiasis. Their life cycle is characterised by distinct parasitic and free-living phases involving mammalian and snail hosts and freshwater. Microarray analysis was used to profile developmental gene expression in the Asian species, Schistosoma japonicum. Total RNAs were isolated from the three distinct environmental phases of the lifecycle – aquatic/snail (eggs, miracidia, sporocysts, cercariae, juvenile (lung schistosomula and paired but pre-egg laying adults and adult (paired, mature males and egg-producing females, both examined separately. Advanced analyses including ANOVA, principal component analysis, and hierarchal clustering provided a global synopsis of gene expression relationships among the different developmental stages of the schistosome parasite. Results Gene expression profiles were linked to the major environmental settings through which the developmental stages of the fluke have to adapt during the course of its life cycle. Gene ontologies of the differentially expressed genes revealed a wide range of functions and processes. In addition, stage-specific, differentially expressed genes were identified that were involved in numerous biological pathways and functions including calcium signalling, sphingolipid metabolism and parasite defence. Conclusion The findings provide a comprehensive database of gene expression in an important human pathogen, including transcriptional changes in genes involved in evasion of the host immune response, nutrient acquisition, energy production, calcium signalling, sphingolipid metabolism, egg production and tegumental function during development. This resource should help facilitate the identification and prioritization of new anti-schistosome drug and vaccine targets for the control of schistosomiasis.

  7. 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).

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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].

  11. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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

  14. Ocorrência de linhagens humana e silvestre de Schistosoma mansoni, na pré-amazônia: I - estudo em moluscos Occurrence of wild and human strains of Schistosoma mansoni in lower Amazonia: I - study in moluscs

    Directory of Open Access Journals (Sweden)

    Othon de Carvalho Bastos

    1982-10-01

    Full Text Available Foram isoladas na região da Baixada Maranhense (Brasil, linhagens humana (H e silvestre(S de Schistosoma mansoni a partir de miracídios eclodidos de ovos encontrados em fezes de doentes humanos autóctones da Região e de fígados de roedores silvestres naturalmente infectados. Biomphalaria glabrata, descentes de caramujos coletados no campo, foram expostos, isoladamente, aos miracídios H e S, mantidos isolados em moluscário e observados durante 100 dias. Moluscos normais foram mantidos nas mesmas condições de ambiente em que foram submetidos os infectados e tomados como controle da experiência. Foram anotados os indices de infecção dos moluscos, as datas da eliminação de cercárias, quantidade de larvas eliminadas e mortalidade dos moluscos. Os dados sugeriram melhor adaptação do esquistossomo da linhagem H à B. glabrata. A linhagem S, por sua vez, foi três vezes mais virulenta do que a linhagem H. Estes dados foram comparados com os encontrados na literatura especializada e verificado diversidades nos comportamentos parasitológicos das linhagens em estudo, quando comparados com os encontrados nas linhagens H e S oriundas do Vale do Rio Paraíba do Sul, no Estado de São Paulo (Brasil.The wild (W and human (H strains of Schistosoma mansoni were isolated in the Lowland Region of the Maranhão State (Brazil. The snail progenies from Biomphalaria glabrata collected from that region were exposed to the W miracidia, obtained from livers of wild rodents, and H miracidia from eggs in human stools. A control gruop of normal snails was kept in the same conditions as the infected one. The date of the elimination of cercariae, the quantity of eliminated larvae, the infection index of the moluscs and the mortality rate of the snails were recorded. These data suggested better adaptation of the H strain to B. glabrata. The W strain presented three times more virulence to snails than the H strain. These results were compared with published

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

    Directory of Open Access Journals (Sweden)

    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

  17. RNA interference in Schistosoma mansoni schistosomula: selectivity, sensitivity and operation for larger-scale screening.

    Directory of Open Access Journals (Sweden)

    Saša Stefanić

    transcript-dependent (from 40 to >75% knockdown relative to controls and this may have contributed to the lack of obvious phenotypes observed, even after prolonged incubations of 3 weeks. Within minutes of their mechanical preparation from cercariae, schistosomula accumulated fluorescent macromolecules in the gut indicating that the gut is an important route through which RNAi is expedited in the developing parasite. CONCLUSIONS: Transient RNAi operates gene-selectively in S. mansoni newly transformed schistosomula yet the sensitivity of individual gene targets varies. These findings and the operational parameters defined will facilitate larger RNAi screens.

  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. The importance of gobies (Gobiidae, Teleostei) as hosts and transmitters of parasites in the SW Baltic

    Science.gov (United States)

    Zander, C. D.; Strohbach, U.; Groenewold, S.

    1993-02-01

    The parasite fauna of five goby species (Gobiidae, Teleostei) was investigated in the Baltic Sea during the period 1987 to 1990. 13 parasite species were found in samples from the Lübeck Bight: Bothriocephalus scorpii, Schistocephalus sp. (Cestoda); Cryptocotyle concavum, Cryptocotyle lingua, Podocotyle atomon, Derogenes varicus (Digenea); Hysterothylacium sp. (cf. auctum), Contracaecum sp., Anisakis simplex (Nematoda); Corynosoma sp., Echinorhynchus gadi, Neoechinorhynchus rutili, Pomphorhynchus laevis (Acanthocephala). The number of parasite species were: 10 in the sand goby Pomatoschistus minutus, 8 in the black goby Gobius niger, 7 in the two-spotted goby Gobiusculus flavescens, 6 in the common goby Pomatoschistus microps, and 5 in the painted goby Pomatoschistus pictus. Neoechinorhynchus rutili occurred only in P. minutus, and Corynosoma sp. only in G. niger. The extent to which the gobies were parasitized clearly depended on the respective ways of life and, moreover, on the kind of prey ingested by the hosts. Additionally, the age of the hosts might be important. The highest rate of parasitism, more than 60%, was reached by Hysterothylacium sp. in G. niger and by Cryptocotyle concavum in P. microps. Infestation incidence lay mostly below 40% which means a satellite species status (Holmes, 1991). The number of parasite species was highest in summer; the highest intensities of single parasites occurred in spring ( Podocotyle atomon) or autumn ( Crytocotyle concavum). Bothriocephalus scorpii, Hysterothylacium sp. and Podocotyle infested their juvenile hosts very early, but only Hysterothylacium was accumulated by G. niger during its whole life span, whereas Bothriocephalus persisted also in older gobies in low intensities. The cercariae of Cryptocotyle spp. penetrate actively into their hosts; all the other parasites named were transmitted in larval form by prey organisms which consisted mainly of planktonic and benthic crustaceans. The gobies were final hosts

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

    Directory of Open Access Journals (Sweden)

    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

  1. Evaluating the Biological and Ecological Factors Influencing Transmission of Larval Digenetic Trematodes: A Test of Second Intermediate Host Specificity of Two North American Halipegus Species.

    Science.gov (United States)

    Stigge, Heather A; Bolek, Matthew G

    2016-12-01

    approximate 2-fold difference in the average percentage of worms that established in odonates from the ostracod, Cypridopsis sp., than from the harpacticoid copepod, Phyllognathopus sp., and the difference was nearly 3-fold between Cypridopsis sp. and the cyclopoid copepod, Thermocyclops sp. Therefore, despite all 3 microcrustacean species becoming infected, not all species were equally suited for transmission and completion of the life cycle. Differences among the 3 microcrustacean species in cercaria ingestion, metacercarial growth and development, and odonate predation rates on infected microcrustacean species were important factors in determining transmission of the 2 Halipegus species to odonate hosts.

  2. Morphology and molecules reveal the alien Posthodiplostomum centrarchi Hoffman, 1958 as the third species of Posthodiplostomum Dubois, 1936 (Digenea: Diplostomidae) in Europe.

    Science.gov (United States)

    Stoyanov, Borislav; Georgieva, Simona; Pankov, Plamen; Kudlai, Olena; Kostadinova, Aneta; Georgiev, Boyko B

    2017-01-01

    Metacercariae of two species of Posthodiplostomum Dubois, 1936 (Digenea: Diplostomidae) were subjected to morphological and molecular studies: P. brevicaudatum (von Nordmann, 1832) from Gasterosteus aculeatus (L.) (Gasterosteiformes: Gasterosteidae), Bulgaria (morphology, cox1 and ITS1-5.8S-ITS2) and Perca fluviatilis L. (Perciformes: Percidae), Czech Republic (morphology, cox1, ITS1-5.8S-ITS2 and 28S); and P. centrarchi Hoffman, 1958 from Lepomis gibbosus (L.) (Perciformes: Centrarchidae), Bulgaria (morphology, cox1 and ITS1-5.8S-ITS2) and Slovakia (cox1 and ITS1-5.8S-ITS2). In addition, cercariae of P. cuticola (von Nordmann, 1832) from Planorbis planorbis (L.) (Mollusca: Planorbidae), Lithuania (morphology and cox1) and metacercariae of Ornithodiplostomum scardinii (Schulman in Dubinin, 1952) from Scardinius erythrophthalmus (L.) (Cypriniformes: Cyprinidae), Czech Republic, were examined (morphology, cox1, ITS1-5.8S-ITS2 and 28S). These represent the first molecular data for species of Posthodiplostomum and Ornithodiplostomum Dubois, 1936 from the Palaearctic. Phylogenetic analyses based on cox1 and ITS1-5.8S-ITS2, using O. scardinii as the outgroup and including the three newly-sequenced Posthodiplostomum spp. from Europe and eight published unidentified (presumably species-level) lineages of Posthodiplostomum from Canada confirmed the distinct status of the three European species (contrary to the generally accepted opinion that only P. brevicaudatum and P. cuticola occur in the Palaearctic). The subspecies Posthodiplostomum minimum centrarchi Hoffmann, 1958, originally described from North America, is elevated to the species level as Posthodiplostomum centrarchi Hoffman, 1958. The undescribed "Posthodiplostomum sp. 3" of Locke et al. (2010) from centrarchid fishes in Canada has identical sequences with the European isolates of P. centrarchi and is recognised as belonging to the same species. The latter parasite, occurring in the alien pumpkinseed sunfish

  3. Biogeography of tropical Indo-West Pacific parasites: a cryptic species of Transversotrema and evidence for rarity of Transversotrematidae (Trematoda) in French Polynesia.

    Science.gov (United States)

    Cribb, Thomas H; Adlard, Robert D; Bray, Rodney A; Sasal, Pierre; Cutmore, Scott C

    2014-04-01

    by other life cycle traits. We hypothesise that the characters of large short-lived cercariae, short-lived miracidia, the absence in the life-cycle of second intermediate hosts that are capable of transporting the species, and definitive and first intermediate hosts that have limited vagility combine to give marine Transversotrematidae limited dispersal capacity and a propensity for localised speciation.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

  6. 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

  7. Hepatic stereology of schistosomiasis mansoni infected-mice fed a high-fat diet

    Directory of Open Access Journals (Sweden)

    Renata Heisler Neves

    2006-10-01

    Full Text Available High-fat diets induce weight gain and fatty liver in wild-type mice. Schistosomiasis mansoni infection also promotes hepatic injury. This study was designed to quantify hepatic alterations in schistosomiasis mansoni-infected mice fed a high fat-rich chow compared to mice fed a standard rodent chow, using stereology. Female SW mice fed each either high-fat diet (29% lipids or standard chow (12% lipids over 8 months, and then were infected with Schistosoma mansoni cercariae. Four experimental groups were studied: infected mice fed a high-fat diet (IHFC or standard chow (ISC, uninfected mice fed a high-fat diet (HFC or standard chow (SC. Mice were sacrificed during early infection (9 weeks from exposure. The following hepatic biometry and the stereology parameters were determined: volume density (hepatocytes [h], sinusoids [s], steatosis [st] and hepatic fibrosis [hf]; numerical density (hepatocyte nuclei - Nv[h]; absolute number of total hepatocyte N[h], normal hepatocyte N[nh], and binucleated hepatocyte N[bh], percentage of normal hepatocyte P[nh] and binucleated hepatocyte P[bh]. IHFC and HFC groups exhibited TC, HDL-C, LDL-C, and body mass significantly greater (p < 0.05 than control group. No significant differences were found regards liver volume (p = 0.07. Significant differences were observed regards P[nh] (p = 0.0045, P[bh] (p = 0.0045, Nv[h] (p = 0.0006, N[h] (p = 0.0125, N[bh] (p = 0.0164 and N[nh] (p = 0.0078. IHFC mice group presented 29% of binucleated hepatocytes compared to HFC group (19%, ISC group (17% and SC (6%. Volume density was significantly different between groups: Vv[h] (p = 0.0052, Vv[s] (p = 0.0025, Vv[st] (p = 0.0004, and Vv[hf] (p = 0.0007. In conclusion, schistosomiasis mansoni infection with concurrent high-fat diet promotes intensive quantitative changes in hepatic structure, contributing to an increasing on hepatic regeneration.

  8. 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

    Directory of Open Access Journals (Sweden)

    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

  9. Experimental schistosomiasis in the Common Marmoset Callithrix jacchus Esquistossomose experimental no Sagüi Callithrix jacchus

    Directory of Open Access Journals (Sweden)

    Ana Luna de Oliveira

    2004-06-01

    Full Text Available In order to evaluate Callithrix jacchus as an animal model for mansoni schistosomiasis, a group of 10 male animals were once percutaneously exposed to 250 cercariae of the Schistosoma mansoni SLM (São Lourenço da Mata strain. Animals were periodically bled for measuring serum level of enzymes and proteins and for blood cell counting. When comparing pre-infection to post-infection values, a significant increase was found for alkaline phosphatase at 15 to 120 days p.i., differential counts of eosinophil at 45 and 60 days, and total protein and global eosinophil counts at 120 days. No Schistosoma mansoni eggs were found in stools. Adult worms of small size were recovered from five animals. At day 120, the number of Schistosoma mansoni eggs/g of tissue was 0-289.7 (liver, 0-30.1 (large intestine and 0-171.4 (small intestine. These findings lead us to classify Callithrix jacchus as a non-permissive host to the SLM strain of Schistosoma mansoni.Com o objetivo de avaliar o Callithrix jacchus (sagüi como modelo experimental para a esquistossomose, um grupo de 10 animais, machos, adultos jovens, foram expostos a 250 cercárias da cepa SLM (São Lourenço da Mata do Schistosoma mansoni, pela via percutânea. A intervalos de 15 dias até 120 dias apos infecção foram dosados os níveis de proteínas totais e enzimas séricas, além de realizados exames parasitológico e hematológico. Aumento significativo foi observado para: fosfatase alcalina a partir do 150 dia; contagem global de eosinófilos aos 120 dias, e diferencial de eosinófilos aos 45 e 60 dias p.i. Nao se observou ovos de Schistosoma nas fezes. Á perfusão cinco animais apresentaram vermes adultos. Todos os vermes encontrados eram diminutos. O número de ovos foi 0-289,7 ovos/g de tecido no fígado, 0-30,1 no intestino grosso, 0-171,4 no intestino delgado. Esta observaçoes levam-nos a concluir que o Callithrix jacchus seja não-permissivo ao Schistosoma.

  10. Development and validation of a mtDNA multiplex PCR for identification and discrimination of Calicophoron daubneyi and Fasciola hepatica in the Galba truncatula snail.

    Science.gov (United States)

    Martínez-Ibeas, A M; González-Warleta, M; Martínez-Valladares, M; Castro-Hermida, J A; González-Lanza, C; Miñambres, B; Ferreras, C; Mezo, M; Manga-González, M Y

    2013-07-01

    Paramphistomosis and Fasciolosis caused by Calicophoron daubneyi and Fasciola hepatica, respectively, are frequent and important trematodoses in ruminant livestock worldwide. Both parasites use the same snail, Galba truncatula, as intermediate host. The aim of this study was to develop and validate an analytical method based on a mitochondrial DNA (mtDNA) multiplex PCR technique which would allow the early and specific identification, in one step, of C. daubneyi and F. hepatica infection in G. truncatula. First of all, a 1035 bp fragment of mtDNA from adult C. daubneyi worms was obtained. Then two pairs of specific mtDNA primers, which amplified a DNA fragment of 885 pb in the case of C. daubneyi, and of 425 pb in that of F. hepatica, were designed. By means of the multiplex PCR technique developed, there was always a specific amplification in samples from adult F. hepatica and C. daubneyi, but not from Calicophoron calicophorum, Cotylophoron cotylophorum, Cotylophoron batycotyle or Dicrocoelium dendriticum. Likewise, specific amplifications of the expected DNA fragments happened in all samples from snails harbouring larval stages of C. daubneyi or F. hepatica, previously detected by microscopy. However, amplifications were not seen when DNA from snails harbouring other Digenea (Plagiorchiidae, Notocotylidae and furcocercous cercariae) was analysed. Moreover, DNA from G. truncatula molluscs free from infection was not amplified. The multiplex PCR assay permitted infection in the snails experimentally infected with 4 miracidia to be detected as early as day 1 p.i. in the case of F. hepatica and with only 2 miracidia from day 2 p.i. in both, C. daubneyi and F. hepatica. Nevertheless it was necessary to wait until days 29 and 33 p.i. to see C. daubneyi and F. hepatica immature redia, respectively, using microscope techniques. The detection limit of the PCR technique was very low: 0.1 ng of DNA from C. daubneyi and 0.001 ng of DNA from F. hepatica. This allowed

  11. A Novel Toll-Like Receptor (TLR Influences Compatibility between the Gastropod Biomphalaria glabrata, and the Digenean Trematode Schistosoma mansoni.

    Directory of Open Access Journals (Sweden)

    Emmanuel A Pila

    2016-03-01

    snails, which shed S. mansoni cercariae 1-week before the susceptible controls. Our results represent the first functional characterization of a gastropod TLR, and demonstrate that BgTLR is an important snail immune receptor that is capable of influencing infection outcome following S. mansoni challenge.

  12. The effect of increasing water temperatures on Schistosoma mansoni transmission and Biomphalaria pfeifferi population dynamics: an agent-based modelling study.

    Directory of Open Access Journals (Sweden)

    Nicky McCreesh

    Full Text Available There is increasing interest in the control and elimination of schistosomiasis. Little is known, however, about the likely effects of increasing water-body temperatures on transmission.We have developed an agent-based model of the temperature-sensitive stages of the Schistosoma and intermediate host snail life-cycles, parameterised using data from S. mansoni and Biomphalaria pfeifferi laboratory and field-based observations. Infection risk is calculated as the number of cercariae in the model, adjusted for their probability of causing infection.The number of snails in the model is approximately constant between 15-31°C. Outside this range, snail numbers drop sharply, and the snail population cannot survive outside the range 14-32°C. Mean snail generation time decreases with increasing temperature from 176 days at 14°C to 46 days at 26°C. Human infection risk is highest between 16-18°C and 1pm and 6-10pm in calm water, and 20-25°C and 12-4pm in flowing water. Infection risk increases sharply when temperatures increase above the minimum necessary for sustained transmission.The model suggests that, in areas where S. mansoni is already endemic, warming of the water at transmission sites will have differential effects on both snails and parasites depending on abiotic properties of the water-body. Snail generation times will decrease in most areas, meaning that snail populations will recover faster from natural population reductions and from snail-control efforts. We suggest a link between the ecological properties of transmission sites and infection risk which could significantly affect the outcomes of interventions designed to alter water contact behaviour--proposing that such interventions are more likely to reduce infection levels at river locations than lakes, where infection risk remains high for longer. In cooler areas where snails are currently found, increasing temperatures may significantly increase infection risk, potentially leading

  13. 家鸭具有作为血吸虫转运宿主的可能性%STUDY ON THE POSSIBILITY OF DUCK AS TRANSPORT HOSTS FOR SCHIS TOSOMA JAPONICUM

    Institute of Scientific and Technical Information of China (English)

    沈立成; 杨艺; 陆珂; 李浩; 石耀军; 朱传刚; 王海生

    2012-01-01

    为研究日本血吸虫(Shistosomia japonicum)卵通过家鸭消化系统后的孵化能力,将人工感染血吸虫尾蚴45d的小鼠剖杀,取肝脏和小肠制成匀浆,并进行虫卵计数,将带有虫卵的肝脏及小肠匀浆液分别灌喂家鸭,观测不同时间收集鸭粪的毛蚴孵出情况。结果显示,经过家鸭体内2h后,粪便中孵化率达到峰值,相对孵化率分别为0.61%和4.066%;7h后,没有虫卵能孵化出毛蚴。同一批次的虫卵所孵化的毛蚴中,大约经过4h后其孵化率达到峰值。结果表明,日本血吸虫虫卵通过家鸭消化系统后仍有部分依然保持孵化能力,家鸭具有可能作为血吸虫的转运宿主,拥有传播血吸虫有效虫卵的能力。%To study the hatchability of Schistosomia japonicum eggs in duck digestive system, mice were infected with S.japonicum cercarias and sacrificed 45 days later. The liver or intestine homogenates containing eggs were fed to ducks. Duck faeces were collected to examine the hatchability of eggs using miracidia hatching technique. Viable eggs were recovered from all ducks although the hatchability significantly declined after the passage through ducks. The hatching peak reached at 2 hours post ingestion. The relative hatchability rates were 0.61% and 4.066% for liver or intestine homogenates. No miracidia were found at 7 hours after ingestion. The hatch rate reached its peak after approximately 4 hours' hatching although some miracidia were found at 12 hours. The eggs recovered from duck faeces maintained hatchability, which suggested that ducks might play a role in transmission of S.japonicum.

  14. Oogram studies in mice infected with Schistosoma mansoni and treated with dexamethasone Oograma em camundongos infectados com Schistosoma mansoni e tratados com dexametasona

    Directory of Open Access Journals (Sweden)

    Marco Victor Hermeto

    1994-04-01

    Full Text Available Mice infected with about 90 cercariae of Schistosoma mansoni (LE strain were treated during five consecutive days with dexamethasone (50 mg/Kg, subcutaneously, starting on the 42th day of infection. Groups of five mice were then daily sacrificed from the first day after onset of treatment until the first day after. The perfusion of the portal system was performed and a piece of the intestine was processed for qualitative and quantitative oograms. This treatment carries to larger numbers of eggs in the tissues of treated mice, when compared with untreated groups. No changes were observed in the kinetics of oviposition, as all stages of viable eggs were observed in the tissues of treated and control mice. These data reinforce the hypothesis of a partial blockade of the egg excretion in immunossupressed mice.Camundongos infectados com cerca de 90 cercárias da cepa LE de Schistosoma mansoni foram tratados durante 5 dias consecutivos com dexametasona (50mg/ Kg, subcutaneamente a partir do 42º dia de infecção. Grupos de cinco camundongos foram sacrificados diariamente após o primeiro dia do início do tratamento até o primeiro dia após o término. A perfusão do sistema porta foi feita e fragmentos do intestino foram processados para a realização de oogramas qualitativos e quantitativos. O tratamento leva a um maior número de ovos nos tecidos dos camundongos tratados, se comparado com os grupos não tratados. Nenhuma mudança foi observada na cinética de oviposição, e ovos viáveis em todos os estádios evolutivos foram observados nos tecidos de camundongos tratados e controles. Estes dados reforçam a hipótese de um bloqueio parcial na saída de ovos dos tecidos do intestino para o lúmem intestinal em camundongos imunossuprimidos.

  15. Effect of ferulic sesquiterpene compounds on the enzymes of schistosomulum%阿魏倍半萜类对血吸虫童虫酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    余小飞; 赵红梅; 卢昊

    2012-01-01

    小鼠感染日本血吸虫尾蚴后第6天起灌服阿魏倍半萜类300rag/(kg·次),每周1次,共4次。于每次给药后的第3、5天收集童虫,制成匀浆,作薄层凝胶电泳,胶中有关同工酶经底物显色,作酶活性定性观察。另设相应时间的不给药对照组。结果显示,该药对苹果酸脱氢酶、6一磷酸甘露糖酶I、酸性磷酸酶有明显抑制作用,对磷酸葡萄糖异构酶的活性影响不明显。该结果表明,阿魏倍半萜类对血吸虫童虫的能量代谢以及对红细胞的消化有抑制作用。%Mice compounds at 300 infected with sehistosome cercariae were orally administrated with ferulic sesquiterpene mg/kg on 6th post-infection once a week for 4 weeks. Schistosomula were collected and ground into homogenate on 3^nl and 5th after every time of administration. Thin layer starch gel electrophoresis was used to observe the activity of enzymes in the homogenate. Control group was also designed (dnlg free mice). The results showed that the activities of malic dehydrogenase,6-phophate mannosease and acid phosphatase were obviously inhibited in the experimental group,but the activity of phosphoglucoisomerase was not inhibited. It indicated that the energymetabolism effect of intestinal wall of the worm on digesting red-ceils could be inhib compounds. of schistosomulum and the it by ferulic sesquiterpene

  16. 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

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. 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

  20. 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.

  1. 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

  2. 臭氧对离体华支睾虫囊蚴生命力的影响%Effects of ozone on the viability of Clonorchis sinensis metacercariae in vitro

    Institute of Scientific and Technical Information of China (English)

    卫萍; 盛金凤; 刘小玲

    2013-01-01

    [Objective]This research studied the effects of ozone on the viability of Clonorchis sinensis metacercariae in vitro to provide reference for exploring methods for killing metacercaria parasite and for meat preservation. [Method] Pseudorasbora parva and silver floating fish liver obtained from the river of Qipuling village, Hengzhou town, Heng County were observed under tabletting microscopy; then, using positive fish tested with liver fluke metacercaria as study subject, the metacercariae from infected fish were obtained using artificial gastric juice digestion. Afterwards, the metacercaria separated into 50/group were divided into several groups in distilled water, effects of different ozone modes, time, and initial concentrations on the isolated metacercariae were compared. [Result]When the ozone passed into the distilled water for 10 min, the mortality rate of metacercariae from first passing the ozone through metacercariae was significantly lower than of the metacercariae from first passing the metacercaria after ozone. By the treatment of first passing metacercaria after ozone, as the ozone access time increased, the metacercaria mortality rate significantly increased. After passing ozone for 10 min, the metacercaria mortality rate reached higher than 70.00%, and the remaining metacercariae without excystation basically exhibited no activities. After passing ozone for 20 min, the metacercaria mortality rate reached 100.00%, so all of the metacercariae exhibited no activities. Under airtight conditions, the higher the initial concentration of ozone in distilled water, the higher the metacercariae mortality rate. The activities of liver fluke metacercaria manifestations in the ozone water were observed as follows: in the beginning of ozone passing, the metacercaria tried to violently break the cercaria walls; as the ozone passing time prolonged, part of the encysted metacercaria broke through the walls, but finally the cercariae activities slowed down until

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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

  5. 重组日本血吸虫磷酸丙糖转移酶免疫保护性的研究%Preliminary study of recombinant the triosephosphate transferase in immuno-protection of Schistosoma japonicum

    Institute of Scientific and Technical Information of China (English)

    陈多玲; 张婧; 姚涌; 汪学龙

    2012-01-01

    Objective To observe the immuno-protection in mice attacked with cercaria for a new vaccine candidate of Schistosoma japonicum, the recombinant protein triosephosphate transferase (SjTPM). Methods The BALB/c mice were immunized with the recombinant SjTPM in the dose of 50μg/100μl、 100μg/100μl and 200μg/100μl, the saline solution was used for control group, then attacked with cercaria. The percentage of worm reduction and egg reduction was calculated to evaluate the immuno-protection effect. HE staining method was used to detect the hepatic changes and granulomatous changes in the liver tissue. Results The percentage of worm reduction was 27.1%,32.1% and 35.2%, respectively, in the experimental groups. The number of eggs in liver tissue was reduced by 34.2% ,39.29% ,43.66%, respectively. There were remarkable difference among the experimental groups and control group by t-test. There was no remarkable difference between the experimental groups by X2-test. Gross observation showed that the livers in control groups were dark brown and hard, with miliary nodules or worm eggs diffused in the livers. The recombinant SjTPM group has some extent of amelioration, the livers were bright red, relative soft and smooth, with less nodules of worm eggs in livers. Hepatic histological section demonstrated that there're generous large granulo- degeneration and necrosis of hepatic cells. The recombinant SjTPM vaccine group reversed the hepatic injury better than the control group. The structure of hepatic lobule was integrated on the whole, and the inflammatory reaction around the worm egg granulomas was light. Conclusion The molecular vaccine of rSjTPM had some immuno-protection effect.It suggested that rSjTPM was a potential candidate of S.japonicum.%目的 观察重组日本血吸虫磷酸丙糖转移酶(rSj-TPM)在小鼠抗血吸虫感染中的免疫保护作用,寻找新的血吸虫疫苗候选分子.方法 以rSj-TPM每鼠50μg/100μl、100μg/100μl和200μg/100μl

  6. Atividade antiparasitária do artemether na esquistossomose mansônica experimental Antischistosomal activity of artemether in experimental Schistosomiasis mansoni

    Directory of Open Access Journals (Sweden)

    Susana Zevallos Lescano

    2004-02-01

    the effect of intramuscular injection of artemether in mice experimentally infected with Schistosoma mansoni , at the time of infection, during schistosomula maturation and after the beginning of egg-laying. METHODS: Eighty adult females Balb/c mice were divided into 8 groups with 10 animals each. Seven groups were infected with S. mansoni using 60 cercariae for each animal, inoculated subcutaneously, and the remaining group was maintained without infection. Among the seven infected groups, six were treated with artemether, according to the following schedule: three groups received doses of 100 mg/kg on days 0, 20 or 60 after inoculation of the cercariae; the other three received 50 mg/kg of artemether, also on days 0, 20 or 60. At the end of the 9th, 10th and 11th weeks after infection all the mice infected with S. mansoni were submitted to fecal examination using the Kato-Katz technique. On the 80th day of the experiment, the surviving animals were sacrificed and submitted to perfusion of the portal system in order to recover the worms. Body, liver and spleen weights of each animal were determined at that time. RESULTS: A reduction in egg-laying and the number of worms recovered was observed in mice treated with artemether (50 or 100 mg/kg on the 20th day after infection. The decrease in the number of worms was more notable among S. mansoni females. A significant decrease in liver and spleen weights was also seen on the 20th day among animals treated with 50 or 100 mg/kg of artemether and also among those that received the drug at a dose of 50 mg/kg 60 days after infection. CONCLUSIONS: Evidence of the antischistosomal activity of artemether was shown, even at a dose of 50 mg/kg, when the drug was administered during the schistosomula maturation period in the portal system of the vertebrate host.

  7. Determinantes ambientais e sociais da esquistossomose mansoni em Ravena, Minas Gerais, Brasil Environmental and social determinants in schistosomiasis mansoni in Ravena, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Pedro Coura-Filho

    1995-06-01

    specific treatment of those infected with S. mansoni. The district contains three locations, Ravenopolis, Ravena and Lavapes, where the prevalence of the endemic disease was, 20.1%, 42.6% and 63.9%, respectively. The prevalence in the district was statistically higher in men. The age brackets that displayed differences by gender were 10-14 and 15-19 years. Severity of infection was statistically different among individuals within the 10-14 year bracket in ali three locations, and in the 15-19 year bracket among individuals from Ravenopolis and Ravena. The hepatointestinal form was associated with age, and individuals under 15 years of age presented risk of infection 8.85 times higher than adults. Multivariable analysis of the factors involved in transmission of the disease showed that Lavapes was independently associated with infection. In that area, poor sanitary conditions and the proximity of houses to streams infested with S. marsoni cercariae facilitated infection of neighborhood women while performing domestic activities, as well as men digging sand from the streams for construction. These results show the focal nature of transmission of the endemic requiring specific intervention for effective control of disease.

  8. 室内繁殖东方田鼠感染日本血吸虫的实验研究%Study of closed colony of Microtus fortis infected with Schistosoma japonicum

    Institute of Scientific and Technical Information of China (English)

    成钢; 曾文虎; 王京仁; 王文彬; 李淑红

    2013-01-01

    目的 比较室内繁殖东方田鼠与昆明鼠感染日本血吸虫后不同阶段脏器病变以及体内日本血吸虫发育与存活状况.方法 采用日本血吸虫尾蚴感染健康东方田鼠和昆明鼠,在感染后12、20、40d剖杀,观察并比较东方田鼠以及昆明鼠肝、肾、肺等脏器组织病变及体内日本血吸虫发育与存活情况.结果 日本血吸虫感染后12、20 d昆明小鼠和感染40d后东方田鼠的内脏器官均未出现明显病变;感染12 d及20d后的东方田鼠肝脏、肾脏及脾脏出现明显白色结节,且以感染12d的组织病变更为明显,部分东方田鼠病变组织仅见于肝脏.病理切片显示,病变肝脏和肾脏组织中存在完整日本血吸虫虫体,与正常组织界限分明;而无病变的肝脏和肾脏组织病理切片未发现虫体.结论 室内繁殖东方田鼠感染日本血吸虫后12d免疫反应剧烈且存在明显的个体差异.%Objective To understand the pathological changes of tissues and organs in Microtusfortis infected with Schistosoma japonicum for further insight into the biological dynamic variation and explore immune mechanisms of M.fortis against S.japonicum infection.Methods The healthy M.fortis and mouse were infected with cercariae of S.japonicum through abdominal skin.On the day 12,20 and 40,the M.fortis and mouse were sacrificed by cervical dislocation and dissected.The liver and kidney slices of M.fortis and mouse of the different groups were prepared and stained with hematoxylin eosin stain (HE) by conventional techniques,respectively.Results We did not find obvious lesions on the internal organs of mouse 12 d and 20 d after the infection and the lesions of M.fortis 40 d after the infection.However,white nodules appeared on the liver,kidney and spleen of the M.fortis 12 d and 20 d after the infection,and there were a lot of S.japonicum worms on pathological sections of inflamed liver and kidney tissues,and the boundary between worms and

  9. 南京所见一种裂体吸虫与日本血吸虫形态及生活史比较%DESCRIPTION OF A KIND OF SCHISTOSOMA IN NANJING REGION

    Institute of Scientific and Technical Information of China (English)

    徐国余; 陈天明; 赵勇进; 陈广梅; 庞浩

    2001-01-01

    In the paper, some morphological and biological materials of a kind of Schistosoma obtained from mice or rabbits experimentally infected with cercariae from natural snail living in Nanjing are presented as follows: (1) Adult worms superficially resemble to Schistosoma japonicum but smaller in size. For instance, male worms from mice 45d after infection measure (7.14±0.64) mm × (0.58±0.03) mm. In average, oral sucker is 0.54 mm ×0.59 mm, and ventral sucker 0.65 mm×0.68 mm which goes beyond the body width and no pronounced rim found. There are usually 8 testes in two series. Dosal integument presents densely clublike spines. Females from mice 45d after infection measure (7.19±1.12) mm×(0.37±0.02) mm. Oral suckers are bigger than ventral ones. The uterus contains as many as 20~80 eggs at one time. Egg has lateral hook-ring spine. (2) The typical habitat for oviposition is in small and terminal veins of superior and inferior mesenteric veins, potal veins in liver and vesical venous plexus. (3) In mice, the patent period is 32.6 d±1.2 d which is shorter than that of S. japonicum while in Oncomelania snails it is 9 wks under 26℃ which is 1 wk longer tahn that of S. japonicum. (4) Study on snail compatibility showed that infection rate of this Schistosma was 3.7%~6.6% but of S. japonicum 31.7%~46.6%.%用自然环境中钉螺逸出的尾蚴感染小鼠和兔,获得了一种比日本血吸虫小的裂体吸虫。雄虫大小(7.14±0.64)mm×(0.58±0.03)mm,口吸盘较大0.54mm×0.59mm;腹吸盘更大0.65mm×0.68mm,超过虫体宽度,且圆边构造不明显;睾丸4~8个,多为8个,重叠排成两行;背部有密集杵状小棘。雌虫(7.19±1.12)mm×(0.37±0.02)mm,子宫内有虫卵20~80个。雌雄合抱寄生在肠系膜下静脉、肠系膜上静脉、肝内门脉血管和膀胱静脉丛的小静脉和末梢静脉中。虫卵有钩状或环状微侧刺。终宿主小鼠的虫卵开放前期32.6d±1.2d,比日本血吸虫短1.4d

  10. Socio-economic, health and nutritional status of the villagers in the Nong Wai irrigation area, Khon Kaen, Northeast Thailand.

    Science.gov (United States)

    Harinasuta, C; Sornamani, S; Migasena, P; Vivatanasesth, P; Pongpaew, P; Intarakao, C; Vudhivai, N

    1976-12-01

    findings indicating that the children had sufficient protein intake. The results of the urinary hydroxyproline-creatinine index suggested that many of the children in both groups of the villages were at marginal malnutrition status. Surveys on domestic animals including cattle, buffaloes, pigs, and field rats revealed no important zoonotic diseases except leptospirosis in a few rats. Some fish were found to harbour metacercariae of Opisthorchis viverrini, while some snails were positive for cercariae of O. viverrini, Schistosoma spindale, and Echinostoma malayanum. The overall findings indicated that the water resource development by establishing better irrigation, resulted in an improved socio-economic and nutritional status among the villagers, but health conditions and associated parasitic diseases and some nutritional deficiency still existed in the children. However, the findings from this study provide only preliminary data concerning the socio-economic status, health, and nutritional status of the villagers in the irrigation area...

  11. 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

  12. Effect of mefloquine administered orally at single, multiple, or combined with artemether, artesunate, or praziquantel in treatment of mice infected with Schistosoma japonicum.

    Science.gov (United States)

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

    2011-02-01

    The purpose of the study is to explore the efficacy of mefloquine administered orally at single, multiple doses, or in combination with artesuante, artemether, or praziquantel in mouse--Schistosoma japonicum model. A total of 205 mice were divided into 4 batches and each batch of mice was infected percutaneously with 40 S. japonicum cercariae for 35 days. The infected mice were treated orally with mefloquine at single doses, multiple daily doses, or combined with artesunate, artemether, or praziquantel, while infected but untreated mice served as control. All treated animals were killed 4 weeks post-treatment for assessment of effect. When infected mice were treated orally with mefloquine at single or multiple daily doses under the same total dose levels, the tendency to decrease the efficacy was seen. Particularly, when a lower single dose of 100 mg/kg was divided equally into five daily doses of 20 mg/kg, the efficacy decreased statistically significant (Pmefloquine or artesuante at a single dose of 100 mg/kg, a moderate effect against schistosomes was observed. No further significant reduction of total and female worm burdens was seen, when the two drugs combined together at the same dose level. On the other hand, administration of mefloquine combined with artesunate at single dose of 50 mg/kg, which exhibited no effect against schistosomes, resulted in significant reduction of total and female worm burdens in comparison with the groups treated with mefloquine and artesunate alone at the same dose level. Similar results were observed in treatment of infected mice with mefloquine in combination with artemether at the smaller dose of 50 mg/kg. The total worm burden was significantly lower than that of control and the female worm burden was also significant lower than that of groups treated with mefloquine and artemether alone. Interestingly, in administration of mefloquine 100 mg/kg combined with artemether 100 mg/kg to the infected mice, all female worms were

  13. Confocal laser scanning microscopic observation on adult Schistosoma japonicum harbored in mice following treatment with single-dose mefloquine.

    Science.gov (United States)

    Xiao, Shu-Hua; Sun, Jun; Xue, Jian

    2012-06-01

    The aim of the present study is to assess the mefloquine-induced alteration of adult Schistosoma japonicum using confocal laser scanning microscopy (CLSM). Eight out of ten mice infected with 60-80 S. japonicum cercariae for 35 days were treated orally with mefloquine at a single dose of 400 mg/kg. Four groups of two mice were killed at 24 h and 3, 7, and 14 days post-treatment, and schistosomes were collected by perfusion from the liver and mesenteric veins, fixed in 70% alcohol, stained with acid carmine, and examined by CLSM. Worms obtained from untreated mice served as controls. Twenty-four hours post-treatment, focal tegument of adult male and female worms, which composed of fine and short villus-like materials, became thicker and longer, or disorder arrangement, while the musculatures beneath the tegument revealed in focal and irregular swelling with various degrees. In the gut of male and female schistosomes, severe dilatation accompanied by swelling, collapse, and peeling of gut mucosa was universal. In the reproductive organs, no apparent alteration in the testis structure of male worms was seen, while in female worms, slight damage to the ovary included loose arrangement of mature ovary cells accompanied by some of them degenerated and collapsed. As to vitelline glands, severe damage, such as swelling, indistinction, fusion or collapse of vitelline cells, and apparent swelling of parenchymal tissues in vitelline gland lobules, was seen. Meanwhile, abnormal ova emerged in the uterus at this time point. Three to 7 days post-treatment, the damage to the worms aggravated either in extent or in severity along with time. In some focally swollen worm body, the parenchymal tissues revealed in severe swelling. In addition, a large piece of degenerated and necrotic parenchymal tissues emerged closed to the severe destructed oral or ventral sucker. In the gut of male and female worms, the major alterations manifested by focal collapse or peeling of mucosa, and

  14. Further studies on mefloquine and praziquantel alone or interaction of both drugs against Schistosoma japonicum in vitro.

    Science.gov (United States)

    Xiao, Shu-hua; Xue, Jian; Zhang, Hao-bing

    2012-03-01

    The aim of the present study is to further understand and analyze the interaction of mefloquine with praziquantel against adult Schistosoma japonicum in vitro. Mice infected with S. japonicum cercariae for 35-37 days were sacrificed, and adult schistosomes were collected by perfusion. Schistosomes were placed to each of 12 wells of a Falcon plate and maintained in RPMI 1640 supplemented by 10% calf serum. For determination of 50% and 95% lethal concentration (LC50 and LC95) of the two drugs in vitro, schistosomes were exposed to mefloquine at concentrations of 1, 2, 3, 4, 5, 6, 7, and 10 μg/mL or praziquantel at concentrations of 0.001, 0.01, 0.05, 0.1, 0.2, 0.5, 1, 10, and 30 μg/mL. The plate was incubated at 37°C in 95% air + 5% CO₂ for 72 h. According to the half-life of oral mefloquine and praziquantel in mice, mefloquine combined with praziquantel simultaneously, mefloquine administered within 1 h after praziquantel and praziquantel administered within 17 h after mefloquine were used to evaluate the effect of mefloquine in combination with praziquantel against S. japonicum in vitro. The results showed that the LC50 and LC95 of mefloquine calculated by the Bliss method were 6.17 μg/mL (95% confidence limits, 5.84-6.517 μg/mL) and 8.703 μg/mL (95% confidence limits, 7.632-9.797 μg/mL), respectively. As to praziquantel, no worm death was seen when schistosomes were exposed to praziquantel at concentrations of 0.005-0.2 μg/mL for 72 h. While in the worms exposed to praziquantel 1, 10, and 30 μg/mL, strong spasmodic contractions of the worm body and vesiculation along the worm surface were observed, but 48-75% of the schistosomes survived the exposure in 72-h incubation. Meanwhile, the number of dead worms that emerged in each group was not proportion to the increasing concentrations. Therefore, it is not appropriate to calculate the LC50 and LC95 of praziquantel. For evaluation of the interaction with the two drugs, praziquantel 0.1 or 0.2

  15. 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

    Directory of Open Access Journals (Sweden)

    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

  16. 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

  17. 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.

  18. 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

    Directory of Open Access Journals (Sweden)

    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.

  19. Studies on Schistosomiasis japonica and Saponins

    Directory of Open Access Journals (Sweden)

    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

  20. Ultrastructural study on the morphological changes to male worms of Schistosoma mansoni after in vitro exposure to allicin Estudo ultraestrutural das alterações morfológicas de vermes machos de Schistosoma mansoni após exposição in vitro à alicina

    Directory of Open Access Journals (Sweden)

    Caliandra Maria Bezerra Luna Lima

    2011-06-01

    Full Text Available INTRODUCTION: Garlic has a wide range of actions, including antibacterial, antiviral, antifungal, antiprotozoal and anthelmintic actions. This antiparasitic activity has been attributed to allicin, which is the main constituent of garlic. The present study aimed to investigate the in vitro activity of allicin on the tegument of adult Schistosoma mansoni worms using scanning electron microscopy. METHODS: Swiss Webster mice were infected with S. mansoni cercariae (100 per mouse and sacrificed 50 days later to acquire the adult worms. These worms were collected by perfusion and placed in RPMI medium 1,640 at 37°C before transferring to RPMI media containing 0 (control, 5, 10, 15 and 20mg/mL of allicin, where they were incubated for 2h. The worms were fixed in 2.5% glutaraldehyde solution, washed twice, post-fixed in osmium tetroxide, washed twice and then dehydrated with ascending grades of ethanol. The samples were air-dried, mounted on stubs, gold coated in an ion sputtering unit and viewed using a scanning electron microscope. RESULTS: A concentration of 5mg/mL caused wrinkling in the tegument; a concentration of 10mg/mL resulted in changes to tubercles and loss or modification of spines. With 15 and 20mg/mL increasing damage to the tegument could be seen, such as vesicle formation and the presence of ulcers. CONCLUSIONS: These findings demonstrate the effect of allicin on adult S. mansoni worms and indicate that most of the changes occur at concentrations greater than that normally indicated for treatment.INTRODUÇÃO: O alho apresenta uma ampla gama de ações, incluindo antibacteriana, antiviral, antifúngico, antiprotozoário e anti-helmíntico. Esta atividade antiparasitária tem sido atribuída à alicina, que é o principal constituinte do alho. O presente estudo teve como objetivo investigar a ação in vitro da alicina no tegumento de vermes adultos de Schistosoma mansoni utilizando a microscopia eletrônica de varredura. M

  1. 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

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

    Directory of Open Access Journals (Sweden)

    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

  3. Cloning and function analysis of high mobility group box 1(HMGB1)protein of Schistosoma japonicum(Mainland strain)%日本血吸虫高速泳动家族B1蛋白基因的克隆表达与功能分析

    Institute of Scientific and Technical Information of China (English)

    姚媛; 许永良; 杨静; 余传信; 宋丽君; 殷旭仁; 王玠; 金一; 沈双; 张伟; 高玒

    2014-01-01

    Objective To clone and express a high mobility group box 1(HMGB1)protein of Schistosoma japonicum(Main-land strain)and analyze its function. Methods The DNA fragment of open reading frame encoding Sj HMGB1 protein was ampli-fied by RT-PCR from the mRNA of S. japonicum worms,then it was subcloned into the expression vector pET28a(+)to form the recombinant expression plasmid SjHMGB1-pET28a. The recombinant expression plasmid was transformed into the component E. coli BL21(DE3),and the tranformant containing recombinant expression plasmid was induced with IPTG to express the recombi-nant protein SjHMGB1. The recombinant SjHMGB1 protein was purified by affinity chromatography with nickel chelating affinity chromatography agarose gel. The Gel retard experiment and animal immunization were performed to analyze the DNA binding ca- pacity and the immunologic property of recombinant SjHMGB1. The expression levels of HMGB1 in different life cycle stages of S. japonicum were analyzed by Western bloting and RT-PCR. Female ICR mice were immunized with the recombinant SjHMGB1 pro-tein and infected with 45±2 cercariae of S. japonicum after three immunizations. Forty-two days post-infection,the worms and eggs of S. japonicum were recovered from the portal vein and liver tissue,respectively. The worm and egg reduction rates were calculat-ed respectively. Results A 530 bp of specific DNA fragment was amplified from mRNA of S. japonicum by RT-PCR,which was the open reading frame(ORF)encoding SjHMGB1protein confirmed by DNA sequencing analysis. The recombinant expression plasmid SjHMGB1-pET28a was constructed by cloning the ORF of SjHMGB1 into a expression vector pET28a(+). The bacterium transformants containing the recombinant plasmid expressed a soluble recombinant protein about 28 kDa after induced by IPTG, and the recombinant SjHMGB1 protein was purified by nickel chelating affinity chromatography. The gel retard experiment showed that the recombinant SjHMGB1 protein could bind

  4. 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

    Institute of Scientific and Technical Information of China (English)

    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].

  5. A potential vector of Schistosoma mansoni in Uruguay Um vetor potencial do Schistosoma mansoni no Uruguai

    Directory of Open Access Journals (Sweden)

    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

  6. Dynamic changes in the collagen metabolism of liver fibrosis at the transcription level in rabbits with Schistosomiasis japonica%兔日本血吸虫病肝纤维化胶原代谢的转录水平动态变化

    Institute of Scientific and Technical Information of China (English)

    陈峰; 蔡卫民; 陈智; 陈祥明; 刘荣华

    2002-01-01

    目的从转录水平研究兔日本血吸虫病肝纤维化形成过程中胶原的合成与降解的规律.方法以日本血吸虫尾蚴感染新西兰兔形成肝纤维化动物模型,于感染后4、6、8、10、12、16、20、24和28周手术取肝脏组织,用RT-PCR加Dot blot法检测肝组织Ⅰ型、Ⅲ型、Ⅳ型胶原以及降解胶原的基质金属蛋白酶MMP-1和MMP-9的mRNA水平,并进行肝组织病理学检测,观察虫卵肉芽肿大小和肝纤维化程度的变化.结果在兔感染血吸虫初期,肝组织Ⅰ型胶原、Ⅲ型胶原、Ⅳ型胶原、MMP-1和MMP-9 mRNA水平均上升,且大多在感染后第10周达到峰值,Ⅰ型胶原mRNA水平是正常的12.0倍,Ⅲ型胶原为11.0倍,Ⅳ型胶原为6.6倍,MMP-1和MMP-9 mRNA水平分别是正常水平的10.0倍和11.0倍,大致与虫卵肉芽肿,即炎症反应变化一致.其后胶原和胶原酶mRNA均下降,至28周,Ⅰ型胶原、Ⅲ型胶原和Ⅳ型胶原mRNA水平降至正常水平的2~3倍(P0.05).本研究显示血吸虫感染初期胶原合成与降解处于平衡状态,而感染后期胶原的合成多于胶原的降解.结论从转录水平证实胶原合成大于降解时可导致肝纤维化形成.%Objective To study the role of the synthesis and degradation of collagen at the transcription level during liver fibrogenesis due to schistosomiasis japonica in rabbits. Methods New Zealand rabbits challenged by cercariae of Schistosoma japonicum (S. japonicum) were served as animal models for liver fibrosis. Liver specimens were collected through operations at 4, 6, 8, 10, 12, 16, 20, 24 and 28 wks after challenge. Type Ⅰ collagen, type Ⅲ collagen, type Ⅳ collagen, MMP-1 and MMP-9 mRNA levels of liver tissue were detected by RT-PCR+Dot blot. The size of egg granulomas and the degree of liver fibrosis were measured by histopathological examinations. Results Type Ⅰ collagen, type Ⅲ collagen, type Ⅳ collagen, MMP-1 and MMP-9 mRNA levels increased simultaneously in the

  7. 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

  8. 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

  9. 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

    Institute of Scientific and Technical Information of China (English)

    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

  10. 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.

  11. 上海市市售食品食源性寄生虫污染状况调查%Investigation on food contamination with parasites in Shanghai market

    Institute of Scientific and Technical Information of China (English)

    张小萍; 马杏宝; 蒋守富; 洪国宝; 傅英华; 何艳燕; 马晓疆; 王真瑜; 张耀光; 朱倩

    2012-01-01

    Objective To understand the contamination status of food with parasites in Shanghai market, so as to provide the evidence for formulating the surveillance strategy in parasitic diseases and provide the technical support in the food safety. Methods The freshwater fish products, marine products, vegetables, snails and frogs were sampled with the cluster random method in the farmer-trades and supermarkets of the 18 districts in Shanghai City during 2005-2010 period, and all the specimen were screened by the digestion method, or crushing method or dissection method or saline floatation method to check the parasite meta-cercaria or larvae or eggs. Results A total of 5 185 specimen in 23 species of fishes were screened in fresh-water products, with parasite infection rate of 1.93%. About 4 033 specimens of 20 species of fishes and shrimps were screened and 1.76% of samples were infected with Clonorchis sinensis. Among all kind of fishes, the highest infection rate was 7.83%(48/613)in Pseudorasbora parve. No any infected specimen was found among 1 152 specimen of fresh water crustacean screened. Anisakis spp. were found in 12.7% of 433 specimens of 23 species of seawater products, among them, the higher infection rate of Anisakis spp. was found in Pneumatophorus japonicas and Trichiurus haiunela with their infection rates of 50.00% (13/26) and 23.46% (42/179), respectively, which much higher than those found in other seawater products (P < 0.01). In 37 kinds of vegetables, the parasite eggs were found in one of 428 specimens with its infection rate of 0.47%, while no any parasite egg was found in 103 specimens of 10 kinds of fruits. No any Angiostrongylus cantonensis larvae were found in 330 snails, 31.37% of 102 frogs were found infected with Spiro-metra mansoni spargana. No any contamination with parasites was found in 116 meat specimens of pigs and cattle. In the same time, the intestinal parasite infection rate of residents was 0.42%(131/31 239). Conclusions It is

  12. 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

  13. Estudo seccional sobre esquistossomose mansônica no Município de Riachuelo, Estado de Sergipe

    Directory of Open Access Journals (Sweden)

    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.

  14. 淮南地区曼氏迭宫绦虫病流行的危险因素调查%Risk factors of Spirometra mansoni taeniasis prevalence in Huainan area

    Institute of Scientific and Technical Information of China (English)

    刘群红; 何云鹏; 陶慧慧; 朱玉霞

    2012-01-01

    The purpose of the study was to explore the current situation of Spirometra mansoni taeniasis and its risk factors in Huainan area.and provide the theoretical basis of guarding against this disease. An epidemiological field investigation has been employed in waters of Huainan geographic region regarding the infection of procercoid in Cyclops, the infection of Sparganum mansoni from frog muscles and the fecal egg infection of Spirometra mansoni from domestic cats or dogs with random sampling for estimating the prevalence of infection due to the parasites described above. Additionally, a survey on the prevalence of Spirometra mansoni taeniasis has been employed regarding environmental and social factors by questionnaire. Result indicates that infection rate with cercariae of Cyclops around the 6 urban districts or counties from Huainan area were 2% in Tianjia'an, 1% in Xiejiaji, 1 % in Bagongshan, 2% in Panji, 2% in Datong, and 3% in Fengtai. Total infection rate of the infected frog was 7. 33% , and ratio on the eggs of Spirometra mansoni detected in the feces of cats and dogs were ranged from 0% to 15% and 0% to 5% respectively. Result of the survey showed that no individual farmer was with the knowledge about prevention of Spirometra mansoni taeniasis (0%). The 14. 7% of the surveyed farmers, in general, were accustomed to prey on frogs; 3. 13% of them had digested frogs under-cooked; 36. 29% had fed the cats or dogs with raw frogs. The overall infection rates with both procercoid of Cyclops and frog Sparganum mansoni appeared considerably high in Huainan areas as a result of the final hosts infected by the eggs. To effectively prevent and control sparganosis mansoni, we should strengthen the medical knowledge popularization and education among farmers.%目的 探讨淮南地区曼氏迭宫绦虫病流行现状及其危险因素,为曼氏迭宫绦虫病的预防提供理论基础.方法 采用现场流行病学调查的方法,对淮南市各辖区水域剑水蚤

  15. 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

  16. Immuno-protection of SJIR-2 DNA vaccine with microspheres adjuvant in mice challenged with Schistosoma japonicum%日本血吸虫SJIR-2纳米微球核酸疫苗的免疫保护性研究

    Institute of Scientific and Technical Information of China (English)

    王正印; 潘丽红; 汪学龙

    2016-01-01

    after the last immunization, each mouse was infected by cercaria of Schistosoma japonicum, sera of mice in each group were collected before each immunization and challenge infection. ELISA was used to de-tect the change of IgG in each group of micesera. 42 days later, all mice were sacrificed. The adult worms and eggs were collected and counted, and the worm and egg reduction rates were calculated as well. Results The recombi-nant plasmid pEGFP-SJIR-2 was successfully constucted, and there was significant difference in the numbers of worm and egg between CHS-PLGA-pEGFP-SJIR-2 group and PBS group ( P<0. 01 ) . The worm andegg reduction rates in CHS-PLGA-pEGFP-SJIR-2 group were 37. 36% and 46. 82% respectively. The IgG levels in mice sera of CHS-PLGA-pEGFP-SJIR-2 group were remarkably higher (P<0. 01) compared with PBS group. On the contrary, there was no significant difference between both pEGFP plasmid group and CHS-PLGA group in the numbers of worm and egg compared with PBS group. Conclusion SJIR-2 nanometer microspheres nucleic acid vaccine has some immuno-protection against Schistosoma japonicum infection in BALB/c mice,while it is worth further studying for it’ s potential value to be a candidate antigen molecule of Schistosoma japonicum vaccine.

  17. Survival of Oncomelania Snails from Lake Regions and Mountain Regions and Their Susceptibility to Schistosoma Japonicum under Simulated Field Conditions%模拟自然条件下湖沼型和山区型钉螺存活率及其血吸虫易感性研究

    Institute of Scientific and Technical Information of China (English)

    龚珍强; 李传昌; 汪雁; 黄重峰; 刘大仁; 陶波; 周宪民; 邹节新

    2014-01-01

    Objective To compare the 4-month survive rates of ribbed shell Oncomelania snails from lake regions of Xingzi County of Jiangxi Province,ribbed shell Oncomelania snails from mountain regions of Yushan County of Jiangxi Province and smooth shell Oncomelania snails from mountain regions of Pengshan County of Sichuan Province and their susceptibility to Schis-tosoma japonicum under simulated natural conditions.Methods Lake-region ribbed shell On-comelania snails,mountain-region ribbed shell Oncomelania snails and mountain-region smooth shell Oncomelania snails were collected from Xingzi County of Jiangxi Province,Yushan County of Jiangxi Province and Pengshan County of Sichuan Province,respectively.The infected and un-infected snails were screened using the cercariae escaping method.The Schistosoma japonicum-in-fected snails from Xingzi County were used to infect a rabbit.The liver was removed and miracidia were obtained after 45 days.Then snails were infected with the miracidia at a ratio of 120 at 26-30 ℃ under fluorescent lamp irradiation.These infected snails were fed for 4 months in Schistoso-miasis Control Station of Xingzi County under simulated natural conditions,and the survival rate and infection rate were determined.Results Oncomelania snails from mountain regions of Yushan County of Jiangxi Province and mountain regions of Pengshan County of Sichuan Province could survive under simulated natural conditions in Xingzi County of Jiangxi Province.But their survival rates were significantly lower than those from lake regions of Xingzi County of Jiangxi Province (P < 0.001 ).Furthermore,Oncomelania snails from lake regions of Xingzi County of Jiangxi Province and mountain regions of Yushan County of Jiangxi Province,but not those from moun-tain regions of Pengshan County of Sichuan Province,were easily infected with Schistosoma ja-ponicum miracidia from Xingzi County of Jiangxi Province.In addition,the infection rate of snails from lake regions of Xingzi

  18. 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

    Directory of Open Access Journals (Sweden)

    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.

  19. 2014年湖南省血吸虫病流行区风险监测结果分析%Analysis on the surveillance over risks of schistosomiasis endemic areas in Hunan Province in 2014

    Institute of Scientific and Technical Information of China (English)

    李广平; 周杰; 胡本骄; 汤凌; 李以义; 杨建平; 任光辉

    2016-01-01

    Objective To make an accurate knowledge on the risk status of schistosomiasis transmis⁃sion in endemic areas in Hunan Province in 2014 for evidences to plan scientific strategies for control and prevention of this disease. Methods Twenty-five administrative villages in 13 counties (cities, districts, farms) were selected as risk surveillance sites, and hatching test(1 aliquot of feces subjected to 3 tests) was used to determine the schistosome infection status in all livestock and feces collected in open fields. Sys⁃tematic sampling method was used to measure the status of snail prevalence, and modified crushing-cer⁃cariae escaping method and loop-mediated isothermal amplification(LAMP) technique were applied to detecting the infected snails. Activities of humans and livestock were also observed in the susceptible zones within the 25 surveillance villages. Results Livestock were being fed in 92%of surveillance villages. The infection rate was 1.10%, 1.00%, 1.00% and 0.93%, respectively in Qingang village under Quyuan administrative district, Jichang village and Beihu village of Yueyang county, Kangling village of Yuanji⁃ang city. Sails were found in marshlands within the 25 surveillance villages, and no positive snails were seen in 23 samples obtained in even number frames and tested with crushing-cercariae escaping method. How⁃ever, 6 positive samples(collected in the odd number frames from the marshland in Mingxing, Hanshou county;Zhongxin, Jinshi city;Yuantan and Dongfanghong, Xiangying county;Baota, Quyuan administrative district and Dingshan, Yunxi district) were detected with LAMP method. Livestock were pastured in 56%of risk areas, and the livestock were over 50 in 4 the susceptible areas(the marshland in Baota;Qingang, Quyu⁃an administrative district; Dingshan and Xinshe, Yunxi district). Human actives(totally 43 people being seen) were found in 44% of risk areas. 607 aliquots of livestock feces, including 592 aliquots of feces from cattle and

  20. Preliminary Observation on the Effect of Mefolquine against Egg Granuloma Formation in the Liver of Mice Infected with Schistosoma japonicum%甲氟喹对感染小鼠日本血吸虫虫卵肉芽肿形成影响的初步观察

    Institute of Scientific and Technical Information of China (English)

    肖树华; 张超威

    2013-01-01

    形成具有抑制作用.%Objective To explore whether mefolquine possesses the effect on granuloma formation induced by Schistosoma japonicum eggs. Methods Seventeen out of twenty-eight mice infected with 20 S. japonicum cercariae for 35 days were treated orally with mefloquine at a single dose of 200 mg/kg, and groups of 2-3 mice were sacrificed at various intervals post-treatment. The livers removed from each group of mice were fixed in 10% formaldhyde. While the remained 11 untreated mice divided into 6 groups (1-2 mice per group) were sacrificed at the same time periods as groups of mice treated with mefloquine, and their livers served as untreated corresponding controls. The granulomas with single egg in the center were counted and their diameters were measured using an ocular micrometer. The liver tissue sections were stained with hematoxylin and eosin (HE), Foot's or Mallory's methods for observation on histopathological alteration of egg granulomas, and on the appearance of reticular and collagen fibers within the granulomas. Results After infected mice were treated with mefloquine for 3, 7, 14, 21, 28 and 35 days, i.e., 38, 42, 49, 56, 63, and 70 days post-infection, the mean diameters of granuloma with single egg measured in the liver tissues section were (161 ±19), (175±13), (195±9), (171±40), (180±13), and (145±25)μm, respectively, and each of them was significantly lower than that of its corresponding control group of (189±18), (197±11), (211±12), (208±19), (203±16), and (207±36) μm (P<0.01 or P<0.05). Histopatological observation showed that in mice treated with mefloquine, the eosinophil-predominant inflammatory cells around the egg granuloma were sustained to 14-21 d post treatment (49-56 d post infection), which was significantly different from the corresponding control groups that all the eggs were surrounded by fibroblasts at 42 d post infection. Up to 28-35 d post treatment (63-70 d post infection), the boundary of egg granulomas distributed in the liver tissues of

  1. 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.

  2. 慢性血吸虫感染对脓毒症小鼠保护作用的研究%The protective effect of chronic schistosoma japonica infestation against sepsis in mice

    Institute of Scientific and Technical Information of China (English)

    杜林林; 梁艳冰; 唐皓; 陈志斌; 李振宇; 吴敬国; 胡旭初; 梁华平; 马中富

    2011-01-01

    preliminarily study the protective effect of chronic schistosoma japonica (SJ)infestation against sepsis in mice and its mechanism. Methods BALB/c male mice were used, and the experiment was divided into three parts. Experiment 1: chronic SJ infestation model was reproduced by SJ cercaria inoculation through abdominal skin for 8 weeks. Twenty mice were randomly grouped into normal group (n=10) and SJ group (n=10). The levels of interleukins (IL-4, IL-10), tumor necrosis factor-α(TNF-α) and interferon-γ (IFN-γ) in serum were detected by enzyme linked immunosorbent assay (ELISA).Real-time polymerase chain reaction (PCR) was employed to detect the levels of IL-10 mRNA and TNF-αmRNA in abdominal macrophages. This experiment was meant to evaluate immune state in mice with chronic SJ infestation. Experiment 2: lipopolysaccharide (LPS) was intraperitoneally injected to reproduce sepsis model. Thirty mice were randomly grouped into LPS group (n=15) and SJ-LPS group (n=15). The levels of cytokines were determined by ELISA at 0, 24, 48 and 72 hours after LPS injection. This experiment was meant to detect the effect of chronic SJ infestation in mice during the septic process. Experiment 3 : two types of sepsis model were reproduced by cecal ligation and puncture (CLP) and LPS injection, respectively. The survival rate of mice with chronic SJ infestation in 72 hours in either type of sepsis was evaluated. Results Experiment 1, compared with normal group [IL-4 (56.32±8.66) ng/L, IL-10 (48.17±7.23) ng/L],chronic SJ infestation showed an increase in serum IL-4 [(151. 35 ± 12. 24) ng/L] and IL-10 [(133. 22 ±11. 09) ng/L, both P<0. 05]. Chronic SJ infestation also resulted in an increase in IL-10 mRNA expression (SJ group 4. 46±1. 82, normal group 1. 52±0. 60) and inhibited TNF-α mRNA expression (SJ group 1. 61±0.93, normal group 2. 32±1.03) in abdominal macrophages (both P<0. 05), indicating that macrophages could be differentiated into alternative activated macrophages