Faculty Opinions recommendation of Community diversity reduces Schistosoma mansoni transmission, host pathology and human infection risk.

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.

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Correlation between Experimental and Human Infection with Schistosoma Mansoni

Nature ◽

10.1038/201899a0 ◽

1964 ◽

Vol 201 (4922) ◽

pp. 899-901 ◽

Cited By ~ 11

Author(s):

KENNETH S. WARREN

Keyword(s):

Schistosoma Mansoni ◽

Human Infection

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Linking rattiness, geography and environmental degradation to spillover Leptospira infections in marginalised urban settings: an eco-epidemiological community-based cohort study in Brazil

10.1101/2021.09.21.21263884 ◽

2021 ◽

Author(s):

Max T Eyre ◽

Fábio N Souza ◽

Ticiana S. A. Carvalho-Pereira ◽

Nivison Nery ◽

Daiana de Oliveira ◽

...

Keyword(s):

Public Health ◽

Public Health Intervention ◽

Spatial Modelling ◽

The United States ◽

Infection Risk ◽

Human Infection ◽

Global Public Health ◽

Entire Study ◽

Urban Settings ◽

Public Health Burden

Background: Zoonotic spillover from animal reservoirs is responsible for a significant global public health burden, but the processes that promote spillover events are poorly understood in complex urban settings. Endemic transmission of Leptospira, the agent of leptospirosis, in marginalised urban communities occurs through human exposure to an environment contaminated by bacteria shed in the urine of the rat reservoir. However, it is unclear to what extent transmission is driven by variation in the distribution of rats or by the dispersal of bacteria in rainwater runoff and overflow from open sewer systems. Methods: We conducted an eco-epidemiological study in a high-risk community in Salvador, Brazil, by prospectively following a cohort of 1,401 residents to ascertain serological evidence for leptospiral infections. A concurrent rat ecology study was used to collect information on the fine-scale spatial distribution of ‘rattiness’, our proxy for rat abundance and exposure of interest. We developed and applied a novel geostatistical framework for joint spatial modelling of multiple indices of disease reservoir abundance and human infection risk. Results: The estimated infection rate was 51.4 (95\%CI 40.4, 64.2) infections per 1,000 follow-up events. Infection risk increased with age until 30 years of age and was associated with male gender. Rattiness was positively associated with infection risk for residents across the entire study area, but this effect was stronger in higher elevation areas (OR 3.27 95\%CI 1.68, 19.07) than in lower elevation areas (OR 1.14 95\%CI 1.05, 1.53). Conclusions: These findings suggest that, while frequent flooding events may disperse bacteria in regions of low elevation, environmental risk in higher elevation areas is more localised and directly driven by the distribution of local rat populations. The modelling framework developed may have broad applications in delineating complex animal-environment-human interactions during zoonotic spillover and identifying opportunities for public health intervention. Funding: This work was supported by the Oswaldo Cruz Foundation and Secretariat of Health Surveillance, Brazilian Ministry of Health, the National Institutes of Health of the United States (grant numbers F31 AI114245, R01 AI052473, U01 AI088752, R01 TW009504 and R25 TW009338); the Wellcome Trust (102330/Z/13/Z), and by the Fundação de Amparo à Pesquisa do Estado da Bahia (FAPESB/JCB0020/2016). M.T.E is supported by an MRC doctorate studentship. F.N.S. participated in this study under a FAPESB doctorate scholarship.

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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

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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.

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Anisakis spp. in fishery products from Japanese waters: Updated insights on host prevalence and human infection risk factors

Parasitology International ◽

10.1016/j.parint.2020.102137 ◽

2020 ◽

Vol 78 ◽

pp. 102137 ◽

Cited By ~ 2

Author(s):

Tiago Leandro Gomes ◽

Karl Marx A. Quiazon ◽

Maho Kotake ◽

Naoki Itoh ◽

Tomoyoshi Yoshinaga

Keyword(s):

Risk Factors ◽

Infection Risk ◽

Human Infection ◽

Infection Risk Factors ◽

Fishery Products ◽

Japanese Waters ◽

Anisakis Spp

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Spatiotemporal Analysis of Cryptosporidium Species/Genotypes and Relationships with Other Zoonotic Pathogens in Surface Water from Mixed-Use Watersheds

Applied and Environmental Microbiology ◽

10.1128/aem.01924-12 ◽

2012 ◽

Vol 79 (2) ◽

pp. 434-448 ◽

Cited By ~ 35

Author(s):

Graham Wilkes ◽

Norma J. Ruecker ◽

Norman F. Neumann ◽

Victor P. J. Gannon ◽

Cassandra Jokinen ◽

...

Keyword(s):

Land Use ◽

Surface Water ◽

Water Samples ◽

Regression Tree ◽

Infection Risk ◽

Human Infection ◽

Classification And Regression Tree ◽

Odds Ratios ◽

Content Type ◽

Zoonotic Pathogens

ABSTRACTNearly 690 raw surface water samples were collected during a 6-year period from multiple watersheds in the South Nation River basin, Ontario, Canada.Cryptosporidiumoocysts in water samples were enumerated, sequenced, and genotyped by detailed phylogenetic analysis. The resulting species and genotypes were assigned to broad, known host and human infection risk classes. Wildlife/unknown, livestock, avian, and human host classes occurred in 21, 13, 3, and <1% of sampled surface waters, respectively.Cryptosporidium andersoniwas the most commonly detected livestock species, while muskrat I and II genotypes were the most dominant wildlife genotypes. The presence ofGiardiaspp.,Salmonellaspp.,Campylobacterspp., andEscherichia coliO157:H7 was evaluated in all water samples. The greatest significant odds ratios (odds of pathogen presence when host class is present/odds of pathogen presence when host class is absent) forGiardiaspp.,Campylobacterspp., andSalmonellaspp. in water were associated, respectively, with livestock (odds ratio of 3.1), avian (4.3), and livestock (9.3) host classes. Classification and regression tree analyses (CART) were used to group generalized host and human infection risk classes on the basis of a broad range of environmental and land use variables while tracking cooccurrence of zoonotic pathogens in these groupings. The occurrence of livestock-associatedCryptosporidiumwas most strongly related to agricultural water pollution in the fall (conditions also associated with elevated odds ratios of other zoonotic pathogens occurring in water in relation to all sampling conditions), whereas wildlife/unknown sources ofCryptosporidiumwere geospatially associated with smaller watercourses where urban/rural development was relatively lower. Conditions that support wildlife may not necessarily increase overall human infection risks associated withCryptosporidiumsince mostCryptosporidiumgenotypes classed as wildlife in this study (e.g., muskrat I and II genotype) do not pose significant infection risks to humans. Consequently, from a human health perspective, land use practices in agricultural watersheds that create opportunities for wildlife to flourish should not be rejected solely on the basis of their potential to increase relative proportions of wildlife fecal contamination in surface water. The present study suggests that mitigating livestock fecal pollution in surface water in this region would likely reduce human infection risks associated withCryptosporidiumand other zoonotic pathogens.

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Cryptosporidium and Giardia in recreational water in Belgium

Journal of Water and Health ◽

10.2166/wh.2015.268 ◽

2015 ◽

Vol 13 (3) ◽

pp. 870-878 ◽

Cited By ~ 9

Author(s):

Amimul Ehsan ◽

Stijn Casaert ◽

Bruno Levecke ◽

Liesbet Van Rooy ◽

Joachim Pelicaen ◽

...

Keyword(s):

Infection Risk ◽

Human Infection ◽

Water Bodies ◽

Recreational Water ◽

Swimming Pools ◽

Giardia Infection ◽

Recreational Activities ◽

Cryptosporidium Oocysts ◽

Water Recreation ◽

Giardia Cysts

The objective of this study was to investigate the presence of Cryptosporidium and Giardia in different recreational water bodies in Belgium and to estimate the infection risk associated with swimming and other recreational activities. Cryptosporidium oocysts and/or Giardia cysts were detected in three out of 37 swimming pools, seven out of 10 recreational lakes, two out of seven splash parks and four out of 16 water fountains. In the swimming pools no infection risk for Cryptosporidium could be calculated, since oocysts were only detected in filter backwash water. The risk of Giardia infection in the swimming pools varied from 1.13 × 10−6 to 2.49 × 10−6 per swim per person. In recreational lakes, the infection risk varied from 2.79 × 10−5 to 5.74 × 10−5 per swim per person for Cryptosporidium and from 7.04 × 10−5 to 1.46 × 10−4 for Giardia. For other outdoor water recreation activities the estimated infection risk was 5.71 × 10−6 for Cryptosporidium and 1.47 × 10−5 for Giardia. However, most positive samples in the recreational lakes belonged to species/genotypes that are either animal-specific or predominantly found in animals. No Cryptosporidium was found in splash parks and water fountains, but the presence of Giardia cysts suggests a risk for human infection. The infection risk of Giardia infection during a 3.5-minute visit to a splash park for children equalled 1.68 × 10−4.

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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

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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.

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