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.

Interactions between the plasma proteins of Biomphalaria glabrata (Gastropoda) and the sporocyst tegument of Schistosoma mansoni (Trematoda)

Parasitology ◽  
1986 ◽  
Vol 92 (3) ◽  
pp. 653-664 ◽  
Author(s):  
C. J. Bayne ◽  
E. S. Loker ◽  
Mary A. Yui
Keyword(s):  
Schistosoma Mansoni ◽  
Plasma Proteins ◽  
Biomphalaria Glabrata ◽  
Rabbit Antibody ◽  
Tegumental Surface ◽  
Immunological Interactions ◽  
Resistant Strains ◽  
Host Parasite ◽  
Susceptibility And Resistance

SUMMARYThe tegumental surface of Schistosoma mansoni sporocysts is the site of both nutritive and immunological interactions with haemolymph cells and plasma of Biomphalaria glabrata, the schistosome intermediate host. Within minutes of being placed in host plasma, sporocysts acquire plasma antigens, and within 3 h host plasma antigens are present on the surface at near steady state. Though a wide variety of peptides is acquired, there is selection. Furthermore, some differences occur in the peptides acquired from the plasma of susceptible and resistant strains of snail. Acquired antigens are rapidly processed, and are predominantly undetectable in tegumental extracts after a few hours. In contrast, rabbit antibody on sporocysts remains in situ for at least 48 h, so under some conditions there is stable expression of certain tegumental antigenic determinants.These data, obtained using antibodies to snail plasma antigens and to sporocyst tegumental antigens, are discussed in the light of current ideas on the cellular and molecular basis of susceptibility and resistance in this host#parasite system.

scholarly journals Transcriptome of the parasitic flatworm Schistosoma mansoni during intra-mammalian development

2019 ◽  
Author(s):  
Arporn Wangwiwatsin ◽  
Anna V. Protasio ◽  
Shona Wilson ◽  
Christian Owusu ◽  
Nancy E. Holroyd ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schistosoma Mansoni ◽  
Chronic Infection ◽  
Egg Laying ◽  
Mammalian Host ◽  
Expression Data ◽  
Mammalian Development ◽  
Host Parasite Interactions ◽  
Parasitic Flatworm ◽  
Host Parasite

AbstractSchistosomes are parasitic blood flukes that survive for many years within the mammalian host vasculature. How the parasites establish a chronic infection in the hostile bloodstream environment, whilst evading the host immune response is poorly understood. The parasite develops morphologically and grows as it migrates to its preferred vascular niche, avoiding or repairing damage from the host immune system. In this study, we investigated temporal changes in gene expression during the intra-mammalian development of Schistosoma mansoni. RNA-seq data were analysed from parasites developing in the lung through to egg-laying mature adult worms, providing a comprehensive picture of in vivo intra-mammalian development. Remarkably, genes involved in signalling pathways, developmental control, and adaptation to oxidative stress were up-regulated in the lung stage. The data also suggested a potential role in immune evasion for a previously uncharacterised gene. This study not only provides a large and comprehensive data resource for the research community, but also reveals new directions for further characterising host–parasite interactions that could ultimately lead to new control strategies for this neglected tropical disease pathogen.Author SummaryThe life cycle of the parasitic flatworm Schistosoma mansoni is split between snail and mammalian (often human) hosts. An infection can last for more than 10 years, during which time the parasite physically interacts with its mammalian host as it moves through the bloodstream, travelling through the lungs and liver, to eventually establish a chronic infection in the blood vessels around the host gut. Throughout this complex journey, the parasite develops from a relatively simple larval form into a more complex, sexually reproducing adult. To understand the molecular basis of parasite interactions with the host during this complex journey we have produced genome-wide expression data from developing parasites. The parasites were collected from experimentally-infected mice over its developmental time-course from the poorly studied lung stage, to the fully mature egg-laying adult worm. The data highlight many genes involved in processes known to be associated with key stages of the infection. In addition, the gene expression data provide a unique view of interactions between the parasite and the immune system in the lung, including novel players in host-parasite interactions. A detailed understanding of these processes may provide new opportunities to design intervention strategies, particularly those focussed on the early stages of the infection that are not targeted by current chemotherapy.

Geographical variations in infectivity and susceptibility in the host-parasite system Schistosoma mansoni/Biomphalaria glabrata: no evidence for local adaptation

Parasitology ◽  
2006 ◽  
Vol 133 (3) ◽  
pp. 313-319 ◽  
Author(s):  
F. PRUGNOLLE ◽  
T. DE MEEÛS ◽  
J.P. POINTIER ◽  
P. DURAND ◽  
A. ROGNON ◽  
...  
Keyword(s):  
Schistosoma Mansoni ◽  
Local Adaptation ◽  
Genetic Factors ◽  
Biomphalaria Glabrata ◽  
Metapopulation Dynamics ◽  
Geographical Variations ◽  
Transplantation Experiment ◽  
Host Parasite ◽  
Parasite Populations ◽  
Transplantation Experiments

We investigated local adaptation in the spatially structured natural Biomphalaria glabrata/Schistosoma mansoni host-parasite system in the marshy forest focus of Guadeloupe using cross-transplantation experiments. We demonstrated strong and highly significant variations in susceptibility/infectivity of host and parasite populations, respectively, but found no evidence of local adaptation neither for S. mansoni nor for B. glabrata. Environmental as well as genetic factors are discussed to explain susceptibility/infectivity variations between both host and parasite populations. The absence of local adaptation is discussed in relation to the metapopulation dynamics of both host and parasite, in particular their relative rates of dispersal at the scale under scrutiny. Our study constitutes the first cross-transplantation experiment concerning this host-parasite system of which both hosts and parasites came directly from the wild, excluding laboratory generations and experimental host passages.

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

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 Observations on two biological races of Schistosoma mansoni

1981 ◽  
Vol 76 (3) ◽  
pp. 287-291 ◽  
Author(s):  
W. Lobato Paraense ◽  
Lygia R. Corrêa
Keyword(s):  
Comparative Study ◽  
Schistosoma Mansoni ◽  
Biomphalaria Glabrata ◽  
Prepatent Period ◽  
Snail Species ◽  
Infection Rates ◽  
Paulo State ◽  
Minas Gerais State ◽  
Belo Horizonte ◽  
Host Parasite

A comparative study of the BH strain of Schistosoma mansoni from Belo Horizonte, Minas Gerais state, infective to Biomphalaria glabrata from the same locality, and the SJ strain from São José dos Campos, São Paulo state, infective to B. tenagophila from the latter locality, showed the following differences: 1. Length of adult worms and size of eggs significantly larger in the BH strain. 2. Higher infection rates in the B. glabrata-BH strain association than in the B. tenagophila-SJ strain association, following exposure of each snail to 1 or 10 miracidia. 3.Longer prepatent period (from penetration of miracidium to first shedding of cercariae) in the B. tenagophila-SJ strain association. 4. Infection of both Biomphalaria species when exposed to hybrid miracidia from crosses between the two strains, at lower levels than those resulting from exposure of each snail species to miracidia of the pure sympatric strain. (Both Biomphalaria populations are practically refractory to infection with the allopatric strain). These results are interpreted as pointing to a better host-parasite adjustment in the B. glabrata-BH strain association than in the B. tenagophila-SJ association. The interfertility between the two strains, which produced viable hybrids infective to both Biomphalaria species, supports the conclusion that the observed differences are merely intraspecific, and that the two strains may be considered distinct biological races of Schistosoma mansoni.

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