scholarly journals Transmission of Schistosoma mansoni under experimental conditions using the bovine - Biomphalaria glabrata - bovine model

1993 ◽  
Vol 35 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Celina M. Modena ◽  
Paulo Marcos Z. Coelho ◽  
Frederico S. Barbosa ◽  
Walter S. Lima
Keyword(s):  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Endemic Area ◽  
Experimental Period ◽  
Biomphalaria Glabrata ◽  
Snail Population ◽  
Experimental Conditions ◽  
Worm Recovery ◽  
The Mean

Three calves experimentally infected with Schistosoma mansoni, and passing viable eggs in feces, as well as 5 normal calves (coming from a non-endemic area for schistosomiasis) kept as controls, were maintained in an enclosure (850 m² in area). In this enclosure, a tank with water received 500 laboratory reared Biomphalaria glabrata. All the control calves were infected for a period ranging from 79 to 202 days after the beginning of the experiment, and afterwards presented viable S. mansoni eggs in feces. The mean worm recovery was 555. The snail population increased throughout the experimental period, showing a high number of B. glabrata infected with S. mansoni (42% on average). According to the present study, bovine has been suggested as having potentially a role in the maintenance of the life cycle of S. mansoni

Transient non-susceptibility toSchistosoma mansoniassociated with atrial amoebocytic accumulations in the snail hostBiomphalaria glabrata

Parasitology ◽  
1987 ◽  
Vol 95 (3) ◽  
pp. 499-505 ◽  
Author(s):  
C. S. Richards ◽  
D. J. Minchella
Keyword(s):  
Population Dynamics ◽  
Schistosoma Mansoni ◽  
Genetic Control ◽  
Old Age ◽  
Biomphalaria Glabrata ◽  
Egg Laying ◽  
Snail Population ◽  
Host Parasite ◽  
Variable Susceptibility

SUMMARYIn someBiomphalaria glabrata–Schistosoma mansonicombinations snails are susceptible to infection as juveniles, but have variable susceptibility as adults. These snails become non-susceptible at the onset of egg-laying and typically revert to susceptibility in old age. Certain stocks ofB. glabratahave the capacity to form amoebocytic accumulations in the atrium, and this ability is under genetic control. The atrial amoebocytic accumulations are transitory, typically appearing at onset of egg-laying and disappearing after a few months. A snail stock which has genetic tendencies for both adult variable susceptibility and atrial amoebocytic accumulations was studied. An association between the time of occurrence of adult non-susceptibility and atrial accumulation is revealed as snails never became infected withS. mansoniwhen amoebocytic accumulations were present. Developing parasites, however, were not necessarily encapsulated and destroyed by amoebocytes. Some sporocysts were able to delay development until the amoebocytic accumulations disappeared. The timing of atrial amoebocytic accumulations and resulting transient non-susceptibility in this host-parasite combination could influence snail population dynamics.

scholarly journals Experimental Evaluation of the Pathogenicity of Different Strains ofSchistosoma mansoni

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Antônio Aurélio Euzébio ◽  
Nádia Regina Borim Zuim ◽  
Arício Xavier Linhares ◽  
Luiz Augusto Magalhães ◽  
Eliana Maria Zanotti-Magalhães
Keyword(s):  
Schistosoma Mansoni ◽  
Experimental Evaluation ◽  
Biomphalaria Glabrata ◽  
Sao Paulo ◽  
São Paulo ◽  
Ascending Colon ◽  
Worm Recovery ◽  
Tissue Area ◽  
Different Strains ◽  
The City

The pathogenesis of three differentSchistosoma mansonistrains 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 fromBiomphalaria tenagophila(SJ and SD strains) andBiomphalaria glabrata(BH strains). The parameters analyzed were as follows: number ofS. mansonieggs 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.

Increased oviposition and growth in immature Biomphalaria glabrata after exposure to Schistosoma mansoni

Parasitology ◽  
1986 ◽  
Vol 93 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Joyce A. Thornhill ◽  
Janet T. Jones ◽  
J. R. Kusel
Keyword(s):  
Schistosoma Mansoni ◽  
Biomphalaria Glabrata ◽  
Median Number ◽  
Egg Laying ◽  
Exposed Group ◽  
Control Group ◽  
Egg Mass ◽  
Trematode Parasite ◽  
Compensatory Response ◽  
The Mean

SUMMARYBiomphalaria glabrata snails are known to be castrated by infection with the trematode parasite Schistosoma mansoni 4–6 weeks post-infection. The pattern of oviposition in the first 35 days post-exposure (p.e.) was investigated, in snails aged 14 weeks and measuring 7–10 mm diameter which had not commenced egg-laying, by counting the numbers of eggs laid in 7-day intervals. A group of exposed snails was compared with a control non-exposed group. The exposed group included both parasitized and non-parasitized snails, and showed a significant increase in the median number of eggs laid during the periods 14–21 and 22–28 days p.e. Throughout the entire 35-day period exposed non-parasitized snails laid significantly more eggs than control snails, while parasitized snails laid significantly more eggs than controls during days 22–28 p.e. and significantly fewer during days 29–35 p.e. Parasitized snails also laid significantly more eggs/egg mass in the period 16–28 days p.e. than did control snails. Growth of the snails was measured. By day 28 p.e. the mean diameter of the exposed group was significantly greater than that of the control group. The increase in oviposition by snails soon after exposure is discussed in terms of a compensatory response for expected future suppression of egg-laying. The fact that parasitized and non-parasitized snails both show increased oviposition indicates that normal development of the parasite is not necessary to trigger the response.

scholarly journals Comparative clinical and ultrasound study of egg-negative and egg-positive individuals from Schistosoma mansoni low morbidity endemic areas, and hospitalized patients with hepatosplenic disease

2005 ◽  
Vol 38 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Telcia V.B. Magalhães ◽  
Giovanni Gazzinelli ◽  
Maria Carolina B. Alvarez ◽  
F.C. Lima e Silva ◽  
Lucia Alves Oliveira Fraga ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Clinical Examination ◽  
Endemic Area ◽  
Left Lobe ◽  
Stool Examination ◽  
Periportal Fibrosis ◽  
Ultrasound Study ◽  
Mean Size ◽  
Midclavicular Line ◽  
The Mean

Two hundred and twenty three subjects from a Schistosoma mansoni low morbidity endemic area and nine hospitalized hepatosplenic patients were submitted to stool test and clinical examination and abdomen ultrasound assessments. According to stool examination and ultrasound results, they were grouped as follows: G1 - 63 Schistosoma mansoni egg-negative individuals; G2 - 141 egg-positive patients and without evidence of periportal fibrosis; G3 - 19 egg-positive patients with periportal echogenicity (3-6mm); and G4 - 9 hepatosplenic patients with periportal echogenicity (> 6mm). Hepatomegaly detected by physical examination of the abdomen evaluated in the midclavicular line was verified in G1, G2 and G3, respectively, in 11.1, 12.1 and 26.3%. In G1, G2 and G3, periportal thickening occurred only in schistosomal patients (8.5%). Mild pathological alterations in patients that cannot yet be detected by clinical examination were detectable in the liver by ultrasound and can be due to fibrosis. The degree of mild periportal fibrosis was diminished in 57.9% of patients 12 months after treatment of schistosomiasis with oxamniquine. At ultrasonography, the mean liver left lobe measurement of G3 was larger than that of G1, and that of G4 larger than that of G1 and G2. The mean size of the spleen of G4 was significantly larger than that of the other three groups, and that of G3 larger than that of G1 and G2.

scholarly journals Analysis of Rhodopsin G Protein-Coupled Receptor Orthologs Reveals Semiochemical Peptides for Parasite (Schistosoma Mansoni) and Host (Biomphalaria Glabrata) Interplay

2021 ◽  
Author(s):  
Phong Phan ◽  
Di Liang ◽  
Min Zhao ◽  
Russell C. Wyeth ◽  
Conor Fogarty ◽  
...  
Keyword(s):  
Life Cycle ◽  
Schistosoma Mansoni ◽  
G Protein ◽  
Serotonin Receptor ◽  
Biomphalaria Glabrata ◽  
Host Finding ◽  
Parasite Development ◽  
Future Research ◽  
Helminth Parasites ◽  
G Protein Coupled

Abstract Background: Schistosomiasis is a medically significant disease caused by helminth parasites of the genus Schistosoma. The schistosome life cycle requires chemically mediated interactions with an intermediate (aquatic snail) and definitive (human) host. Blocking parasite development within the snail stage requires improved understanding of the interactions between the snail host and the Schistosoma water-borne free-living form (miracidium). Innovations in snail genomics and aquatic chemical communication provide an ideal opportunity to explore snail-parasite coevolution at the molecular level. Rhodopsin G protein-coupled receptors (GPCRs) are of particular interest in studying how trematode parasites navigate towards their snail hosts. The potential role of GPCRs in parasites makes them candidate targets for new antihelminthics that disrupt the intermediate host life-cycle stages, thus preventing subsequent human infections.Results: A genomic-bioinformatic approach was used to identify GPCR orthologs between the snail Biomphalaria glabrata and miracidia of its obligate parasite Schistosoma mansoni. We show that 8 S. mansoni rhodopsin GPCRs expressed within the miracidial stage share overall amino acid similarity with 8 different B. glabrata rhodopsin GPCRs, particularly within transmembrane domains, suggesting conserved structural features. These GPCRs include an orphan peptide receptor as well as several with strong sequence homologies with rhabdomeric opsin receptors, a serotonin receptor, a sulfakinin (SK) receptor, an allatostatin-A (buccalin) receptor and an FMRFamide receptor. Buccalin and FMRFa peptides were identified in water conditioned by B. glabrata, and we show synthetic buccalin and FMRFa can stimulate significant rates of change of direction and turn-back responses in S. mansoni miracidia.Conclusions: Ortholog GPCRs were identified in S. mansoni miracidia and B. glabrata. These GPCRs may detect similar ligands, including snail-derived odorants that could facilitate miracidial host finding. These results lay the foundation for future research elucidating the mechanisms by which GPCRs mediate host finding which can lead to the potential development of novel anti-schistosome interventions.

Influence of intramolluscan larval stages of Echinostoma liei on the infectivity of Schistosoma mansoni cercariae

1990 ◽  
Vol 64 (1) ◽  
pp. 71-74 ◽  
Author(s):  
J. Jourdane ◽  
J. B. Mounkassa ◽  
D. Imbert-Establet
Keyword(s):  
Schistosoma Mansoni ◽  
Interspecific Competition ◽  
Control Experiment ◽  
Marked Decrease ◽  
Biomphalaria Glabrata ◽  
Strong Decrease ◽  
Larval Stages ◽  
The Mean

ABSTRACTDuring co-infection of Biomphalaria glabrata with Schistosoma mansoni and Echinostoma liei, S. mansoni cercariae released before the complete resorption of S. mansoni sporocysts show a very strong decrease of their infectivity in mice. Under conditions of high interspecific competition (i.e. when the snails are infected by E. liei 8 days after infection by S. mansoni), the mean overall worm return is five times lower than that of the control experiment. A marked decrease of the infectivity of cercariae is also noted when snails, infected exclusively with either sporocysts of S. mansoni or rediae of E. liei, are associated in the same tank.

scholarly journals Evaluation of original Roundup® effects on Biomphalaria glabrata (Say, 1818)

Biotemas ◽  
2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Marta Julia Faro ◽  
Vanessa Silva Moura ◽  
Ronaldo Carvalho Augusto ◽  
Mauricio Carvalho Vasconcellos
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Schistosoma Mansoni ◽  
Reproductive Biology ◽  
Experimental Period ◽  
Biomphalaria Glabrata ◽  
Reproductive Activity ◽  
Lethal Concentration ◽  
Control Group ◽  
Egg Masses

The objective of this work is to evaluate the action of original Roundup® on the snail Biomphalaria glabrata infected and not infected by Schistosoma mansoni by observing its mortality and reproductive biology. Snails were submitted for 30 days to aqueous solutions of original Roundup at concentrations of 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.018, 0.016, 0.014, 0.012 and 0.01 (%) to determine LC50. To analyze the reproductive activity of B. glabrata, against the pesticide, four B. glabrata groups were formed: infected and exposed to the pesticide; infected and not exposed (control); not infected and exposed; and not infected and not exposed(control). LC50 (0.012% aqueous solution of original Roundup) caused mortality of at most up to 95% for 24, 48 and 72 h during the experimental period (30 days), and lost effect totally after 27 days. The reproductive activity of the non-infected and exposed snails was 30.3 ± 20.5 eggs in 2.7 ± 1.2 egg masses, and there was a reduction of 51% in the average number of hatched snails (11.5 ± 7.5) in comparison to the control group (23.9 ± 18.0) for four weeks (p = 0.003). The results indicate that the lethal concentration (LC50) of the 0.012% aqueous solution of original Roundup has a significant action on Biomphalaria glabrata for up to 27 days. Roundup significantly diminished the fertility of infected and exposed snails in comparison with the control group.

scholarly journals Biological parameters of Amblyomma coelebs Neumann, 1906 (Acari: Ixodidae) under experimental conditions

2018 ◽  
Vol 27 (1) ◽  
pp. 80-85 ◽  
Author(s):  
André de Abreu Rangel Aguirre ◽  
Vinicius da Silva Rodrigues ◽  
Ivaneide Nunes da Costa ◽  
Marcos Valerio Garcia ◽  
Leandro de Oliveira Souza Higa ◽  
...  
Keyword(s):  
Life Cycle ◽  
Blood Meal ◽  
Egg Mass ◽  
Average Weight ◽  
Biological Parameters ◽  
Natural Conditions ◽  
Experimental Conditions ◽  
Forest Reserve ◽  
The Mean ◽  
Hatching Rates

Abstract One generation of Amblyomma coelebs life cycle under experimental conditions was evaluated. Ten tick pairs were allowed to feed on rabbits under laboratory conditions (LC), resulting six engorged females with a mean weight of 1,403.9 mg. Two females were maintained in a forest reserve under natural conditions (NC), and four were maintained in incubators (LC). The engorgement period lasted 10.33 days. Pre-oviposition periods were 10.75 (NC) and 22 days (LC). The mean egg-mass weight was 514.76 mg, and the blood meal conversion index was 36.67% (LC). Incubation period under NC and LC were 91 and 56.33 days and hatching rates were 50% and 28.33%, respectively. Larval engorgement period ranged from 4 to 10 days, with average weight of 1.1 mg. Engorged larvae were incubated under NC and LC, with a premolt period of 27 to 36 days and molting rate of 7.1% and 28.7%, respectively. Nymphal engorgement period ranged from 5 to 7 days, with a mean weight of 18.8 mg and a recovery rate of 54.54%. In LC, the ecdysis mean period was 24.5 days, and molting rate was 44.44%, resulting in 24 adult A. coelebs. Our results show a life cycle of 187.45 (NC) and 149 (LC) days.

Thermal preferences of resistant and susceptible strains ofBiomphalaria glabrata(Gastropoda) exposed toschistosoma mansoni(Trematoda)

Parasitology ◽  
1991 ◽  
Vol 103 (3) ◽  
pp. 357-362 ◽  
Author(s):  
H. Lefcort ◽  
C. J. Bayne
Keyword(s):  
Schistosoma Mansoni ◽  
Resistant Strain ◽  
Thermal Gradient ◽  
Biomphalaria Glabrata ◽  
Defense System ◽  
Significant Drop ◽  
Preferred Temperature ◽  
Post Exposure ◽  
The Mean ◽  
Thermal Preferences

The thermal preferences of two strains of the snailBiomphalaria glabrata, one resistant to, and one susceptible to, the parasiteSchistosoma mansoniwere determined in an aquatic thermal gradient. Snails were tested without exposure to the parasite, and 2 h and 5 weeks after exposure to trematode miracidia. The mean temperature selected by susceptible strain snails 2 h post-exposure tended to be lower than that of unexposed controls, although this was not statistically significant. In this strain, at 5 weeks post-exposure, the preferred temperature dropped by 1.9±0.5°C. The resistant strain displayed a significant drop of 1.8±0.6°C 2 h post-exposure. These results are consistent with the hypothesis that a drop in mean temperatures selected by snails is due to altered levels of endogenous cytokines such as IL-1 or TNF in association with parasite activation of the snail internal defense system.

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