Correlation between Experimental and Human Infection with Schistosoma Mansoni

Global biodiversity loss and disease emergence are two of the most challenging issues confronting science and society. Recently, observed linkages between species-loss and vector-borne infections suggest that biodiversity may help reduce pathogenic infections in humans and wildlife, but the mechanisms underlying this relationship and its applicability to a broader range of pathogens have remained speculative. Here, we experimentally evaluated the effects of host community structure on transmission of the human pathogen, Schistosoma mansoni , which alternates between snail intermediate hosts and vertebrate definitive hosts. By manipulating parasite exposure and community diversity, we show that heterospecific communities cause a 25–50 per cent reduction in infection among snail hosts ( Biomphalaria glabrata ). Infected snails raised alongside non-host snails ( Lymnaea or Helisoma sp.) also produced 60–80 per cent fewer cercariae, suggesting that diverse communities could reduce human infection risk. Because focal host density was held constant during experiments, decreases in transmission resulted entirely from diversity-mediated pathways. Finally, the decrease in infection in mixed-species communities led to an increase in reproductive output by hosts, representing a novel example of parasite-mediated facilitation. Our results underscore the significance of community structure on transmission of complex life-cycle pathogens, and we emphasize enhanced integration between ecological and parasitological research on the diversity–disease relationship.

Download Full-text

Known Allergen Structures Predict Schistosoma mansoni IgE-Binding Antigens in Human Infection

Frontiers in Immunology ◽

10.3389/fimmu.2015.00026 ◽

2015 ◽

Vol 6 ◽

Cited By ~ 14

Author(s):

Edward J. Farnell ◽

Nidhi Tyagi ◽

Stephanie Ryan ◽

Iain W. Chalmers ◽

Angela Pinot de Moira ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Human Infection ◽

Ige Binding

Download Full-text

Risk assessment for the implementation of controlled human Schistosoma mansoni infection trials in Uganda

AAS Open Research ◽

10.12688/aasopenres.12972.1 ◽

2019 ◽

Vol 2 ◽

pp. 17 ◽

Cited By ~ 1

Author(s):

Jan Pieter Koopman ◽

Moses Egesa ◽

Anne Wajja ◽

Moses Adriko ◽

Jacent Nassuuna ◽

...

Keyword(s):

Risk Assessment ◽

The Netherlands ◽

Schistosoma Mansoni ◽

Vaccine Development ◽

Natural Infection ◽

Parasitic Infection ◽

Human Infection ◽

Sub Saharan Africa ◽

Infection Model ◽

Road Map

Schistosomiasis is a parasitic infection highly prevalent in sub-Saharan Africa, and a significant cause of morbidity; it is a priority for vaccine development. A controlled human infection model for Schistosoma mansoni (CHI-S) with potential to accelerate vaccine development has been developed among naïve volunteers in the Netherlands. Because responses both to infections and candidate vaccines are likely to differ between endemic and non-endemic settings, we propose to establish a CHI-S in Uganda where Schistosoma mansoni is endemic. As part of a “road-map” to this goal, we have undertaken a risk assessment. We identified risks related to importing of laboratory vector snails and schistosome strains from the Netherlands to Uganda; exposure to natural infection in endemic settings concurrently with CHI-S studies, and unfamiliarity of the community with the nature, risks and rationale for CHI. Mitigating strategies are proposed. With careful implementation of the latter, we believe that CHI-S can be implemented safely in Uganda. Our reflections are presented here to promote feedback and discussion.

Download Full-text

Increased Blastogenic Responses to Worm Antigen and Loss of Adherent Suppressor Cell Activity after Treatment for Human Infection with Schistosoma mansoni

The Journal of Infectious Diseases ◽

10.1093/infdis/151.2.320 ◽

1985 ◽

Vol 151 (2) ◽

pp. 320-324 ◽

Cited By ~ 7

Author(s):

J. J. Ellner ◽

D. J. Tweardy ◽

G. S. Osman ◽

C. Wilson ◽

A. El Kholy ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Cell Activity ◽

Suppressor Cell ◽

Human Infection

Download Full-text

Interaction ofSchistosoma mansoniSporocysts and Hemocytes ofBiomphalaria

Journal of Parasitology Research ◽

10.1155/2012/743920 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 17

Author(s):

D. Negrão-Corrêa ◽

A. C. A. Mattos ◽

C. A. J. Pereira ◽

R. L. Martins-Souza ◽

P. M. Z. Coelho

Keyword(s):

Developing Countries ◽

Latin America ◽

Schistosoma Mansoni ◽

Intermediate Host ◽

Human Infection ◽

Alternative Strategy ◽

Human Populations ◽

Defense System ◽

Soluble Components

Human infection bySchistosoma mansoniaffects more than 100 million people worldwide, most often in populations of developing countries of Africa, Asia, and Latin America. The transmission ofS. mansoniin human populations depends on the presence of some species ofBiomphalariathat act as an intermediate host. The compatibility betweenS. mansoniand its intermediate host is influenced by behavioral, physiological, and genetical factors of the mollusc and the parasite. The susceptibility level of the mollusc has been attributed to the capacity of internal defense system (IDS)—hemocytes and soluble components of the hemolymph—to recognize and destroy the parasite, and this will be the center of interest of this paper. The schistosome-resistantBiomphalariacan be an alternative strategy for the control of schistosomiasis.

Download Full-text

Hidden association between Schistosoma mansoni and Ascaris lumbricoides infections

Revista de Ciências Médicas e Biológicas ◽

10.9771/cmbio.v10i2.5265 ◽

2011 ◽

Vol 10 (2) ◽

pp. 146

Author(s):

Munir Chamone ◽

Elza Erichsen ◽

Gregorio Saraiva Atuncar ◽

Alan Lane De Melo

Keyword(s):

Immune Response ◽

Schistosoma Mansoni ◽

Ascaris Lumbricoides ◽

Human Infection ◽

Negative Association ◽

Cytotoxic Antibodies ◽

Cytotoxic Antibody

The parasitism by Ascaris lumbricoides tends to affect the course of human infection with Schistosoma mansoni on several levels. At least two aspects were addressed in this communication: (1) the influence of the immune response with complement-activating antibody functions (cytotoxic antibody against schistosomula) and (2) the interference between these species of helminths indicated by analyses carried out after the rearrangement of data from seven prevalence surveys from the literature to illustrate our purpose. In fact, the approach focusing on these seven hidden authors' contributions has not been previously submitted considering the associations between S. mansoni and A. lumbricoides infections. Present findings suggest that the occurrence of A. lumbricoides infection affects both the development of cytotoxic antibodies against schistosomula and the prevalence of S. mansoni infection that features a negative association.

Download Full-text

Comparison of different chemotherapy strategies against Schistosoma mansoni in Machakos District, Kenya: effects on human infection and morbidity

Parasitology ◽

10.1017/s0031182000059850 ◽

1991 ◽

Vol 103 (3) ◽

pp. 339-355 ◽

Cited By ~ 52

Author(s):

A. E. Butterworth ◽

R. F. Sturrock ◽

J. H. Ouma ◽

G. G. Mbugua ◽

A. J. C. Fulford ◽

...

Keyword(s):

Schistosoma Mansoni ◽

Primary Schools ◽

Incidence Rates ◽

Human Infection ◽

Intensity Of Infection ◽

Pre Treatment ◽

Long Term Impact ◽

Number Of Individuals ◽

Theoretical Considerations

A comparison was made of the long-term impact of different methods of administration of chemotherapy (oxamniquine, 30 mg/kg in divided doses; or praziquantel, 40 mg/kg) on prevalence and intensity of Schistosoma mansoni infection in four areas in Kangundo Location, Machakos District, Kenya. In Area A, treatment was offered in October 1983 and again in April 1985 to all infected individuals. In Area H, treatment was offered in April 1985 to individuals excreting ≥ 100 eggs per gram (epg) of faeces. In Area H, treatment was offered in April 1985 to all infected school children, within the framework of the primary schools. In the witness area, Area W, treatment was given in April 1985, for ethical reasons, to a small number of individuals excreting ≥ 800 epg. Prevalence and intensities of infection were subsequently monitored at yearly intervals for three complete post-treatment years. In the Area S schools, clinical examination was also carried out at yearly intervals. Treatment of all infected individuals on two occasions (Area A) was the most effective and long-lasting way of reducing prevalence and intensity of infection. In this area, however, some earlier interventions had been carried out and pre-treatment intensities were lower than in the other areas. Treatment only of infected schoolchildren (Area S) also had a marked and prolonged effect, comparable to or better than treatment of individuals with heavy infections (Area H). Treatment of infected schoolchildren also caused a persistent reduction in the prevalence of hepatomegaly, and there was suggestive evidence from intensities of infection in community stool surveys (but not from incidence rates) of an effect on transmission. In all study areas, reinfection was most rapid and most intense among children. These findings are discussed in the light of theoretical considerations and of results from other studies, both on schistosomiasis and on intestinal helminths. We conclude that, in areas of low morbidity such as Kangundo, chemotherapy of schoolchildren only, at intervals of up to 3 years, is a satisfactory way of producing a long-term reduction in both intensity of infection and morbidity.

Download Full-text

Risk assessment for the implementation of controlled human Schistosoma mansoni infection trials in Uganda

AAS Open Research ◽

10.12688/aasopenres.12972.2 ◽

2019 ◽

Vol 2 ◽

pp. 17

Author(s):

Jan Pieter Koopman ◽

Moses Egesa ◽

Anne Wajja ◽

Moses Adriko ◽

Jacent Nassuuna ◽

...

Keyword(s):

Risk Assessment ◽

The Netherlands ◽

Schistosoma Mansoni ◽

Vaccine Development ◽

Natural Infection ◽

Parasitic Infection ◽

Human Infection ◽

Sub Saharan Africa ◽

Infection Model ◽

Road Map

Schistosomiasis is a parasitic infection highly prevalent in sub-Saharan Africa, and a significant cause of morbidity; it is a priority for vaccine development. A controlled human infection model for Schistosoma mansoni (CHI-S) with potential to accelerate vaccine development has been developed among naïve volunteers in the Netherlands. Because responses both to infections and candidate vaccines are likely to differ between endemic and non-endemic settings, we propose to establish a CHI-S in Uganda where Schistosoma mansoni is endemic. As part of a “road-map” to this goal, we have undertaken a risk assessment. We identified risks related to importing of laboratory vector snails and schistosome strains from the Netherlands to Uganda; exposure to natural infection in endemic settings concurrently with CHI-S studies, and unfamiliarity of the community with the nature, risks and rationale for CHI. Mitigating strategies are proposed. With careful implementation of the latter, we believe that CHI-S can be implemented safely in Uganda. Our reflections are presented here to promote feedback and discussion.

Download Full-text