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Aslan IH, Pourtois JD, Chamberlin AJ, Mitchell KR, Mari L, Lwiza KM, Wood CL, Mordecai EA, Yu A, Tuan R, Palasio RGS, Monteiro AMV, Kirk D, Athni TS, Sokolow SH, N’Goran EK, Diakite NR, Ouattara M, Gatto M, Casagrandi R, Little DC, Ozretich RW, Norman R, Allan F, Brierley AS, Liu P, Pereira TA, De Leo GA. Re-assessing thermal response of schistosomiasis transmission risk: Evidence for a higher thermal optimum than previously predicted. PLoS Negl Trop Dis 2024; 18:e0011836. [PMID: 38857289 PMCID: PMC11207148 DOI: 10.1371/journal.pntd.0011836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 06/26/2024] [Accepted: 05/23/2024] [Indexed: 06/12/2024] Open
Abstract
The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis' thermal optimum at 21.7°C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3°C and 23.6-27.9°C (95% CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.
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Affiliation(s)
- Ibrahim Halil Aslan
- Department of Biology, Stanford University, Stanford, California, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Julie D. Pourtois
- Department of Biology, Stanford University, Stanford, California, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Andrew J. Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Kaitlyn R. Mitchell
- Department of Biology, Stanford University, Stanford, California, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Lorenzo Mari
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Kamazima M. Lwiza
- School of Marine and Atmospheric Sciences, Stony Brook University, New York, New York, United States of America
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Erin A. Mordecai
- Department of Biology, Stanford University, Stanford, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Ao Yu
- Department of Earth System Science, Stanford University, Stanford, California, United States of America
| | - Roseli Tuan
- Pasteur Institute, São Paulo Health Public Office, São Paulo, Brazil
| | | | | | - Devin Kirk
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Tejas S. Athni
- Department of Biology, Stanford University, Stanford, California, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Susanne H. Sokolow
- Department of Biology, Stanford University, Stanford, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | | | | | | | - Marino Gatto
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Renato Casagrandi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - David C. Little
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Reed W. Ozretich
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Rachel Norman
- Computing Science and Mathematics, University of Stirling, Stirling, United Kingdom
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Andrew S. Brierley
- Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, United Kingdom
| | - Ping Liu
- School of Marine and Atmospheric Sciences, Stony Brook University, New York, New York, United States of America
| | - Thiago A. Pereira
- Institute for Stem Cell Biology and Regenerative Medicine, School of Medicine, Stanford University, Stanford, California, United States of America
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Stanford, California, United States of America
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
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Aslan IH, Pourtois JD, Chamberlin AJ, Mitchell KR, Mari L, Lwiza KM, Wood CL, Mordecai EA, Yu A, Tuan R, Palasio RGS, Monteiro AM, Kirk D, Athni TS, Sokolow SH, N’Goran EK, Diakite NR, Ouattara M, Gatto M, Casagrandi R, Little DC, Ozretich RW, Norman R, Allan F, Brierley AS, Liu P, Pereira TA, De Leo GA. Re-assessing thermal response of schistosomiasis transmission risk: evidence for a higher thermal optimum than previously predicted. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.01.04.24300851. [PMID: 38826336 PMCID: PMC11142288 DOI: 10.1101/2024.01.04.24300851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis' thermal optimum at 21.7 °C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3 °C and 23.6-27.9 °C (95 % CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.
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Affiliation(s)
- Ibrahim Halil Aslan
- Department of Biology, Stanford University, Stanford, CA, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Julie D. Pourtois
- Department of Biology, Stanford University, Stanford, CA, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | | | - Kaitlyn R. Mitchell
- Department of Biology, Stanford University, Stanford, CA, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
| | - Lorenzo Mari
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Kamazima M. Lwiza
- School of Marine and Atmospheric Sciences Stony Brook University, New York, NY, USA
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA
| | - Erin A. Mordecai
- Department of Biology, Stanford University, Stanford, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | - Ao Yu
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - Roseli Tuan
- Pasteur Institute, São Paulo Health Public Office, São Paulo, SP, Brazil
| | | | | | - Devin Kirk
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Tejas S. Athni
- Department of Biology, Stanford University, Stanford, CA, USA
- Harvard Medical School, Boston, MA, USA
| | - Susanne H. Sokolow
- Department of Biology, Stanford University, Stanford, CA, USA
- Woods Institute for the Environment, Stanford University, Stanford, CA, USA
| | | | - Nana R. Diakite
- Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d’Ivoire
| | - Mamadou Ouattara
- Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d’Ivoire
| | - Marino Gatto
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Renato Casagrandi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - David C. Little
- Institute of Aquaculture, University of Stirling, Stirling, UK
| | | | - Rachel Norman
- Computing Science and Mathematics, University of Stirling, Stirling, UK
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, London, UK
| | - Andrew S. Brierley
- Scottish Oceans Institute, School of Biology, University of St. Andrews, St. Andrews, UK
| | - Ping Liu
- School of Marine and Atmospheric Sciences Stony Brook University, New York, NY, USA
| | - Thiago A. Pereira
- Institute for Stem Cell Biology and Regenerative Medicine, School of Medicine, Stanford University, Stanford, CA, USA
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Stanford, CA, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
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Status Quo and Future Perspectives of Molecular and Genomic Studies on the Genus Biomphalaria-The Intermediate Snail Host of Schistosoma mansoni. Int J Mol Sci 2023; 24:ijms24054895. [PMID: 36902324 PMCID: PMC10003693 DOI: 10.3390/ijms24054895] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 03/06/2023] Open
Abstract
Schistosomiasis, or also generally known as bilharzia or snail fever, is a parasitic disease that is caused by trematode flatworms of the genus Schistosoma. It is considered by the World Health Organisation as the second most prevalent parasitic disease after malaria and affects more than 230 million people in over 70 countries. People are infected via a variety of activities ranging from agricultural, domestic, occupational to recreational activities, where the freshwater snails Biomphalaria release Schistosoma cercariae larvae that penetrate the skin of humans when exposed in water. Understanding the biology of the intermediate host snail Biomphalaria is thus important to reveal the potential spread of schistosomiasis. In this article, we present an overview of the latest molecular studies focused on the snail Biomphalaria, including its ecology, evolution, and immune response; and propose using genomics as a foundation to further understand and control this disease vector and thus the transmission of schistosomiasis.
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Modeling the efficacy of CRISPR gene drive for snail immunity on schistosomiasis control. PLoS Negl Trop Dis 2022; 16:e0010894. [DOI: 10.1371/journal.pntd.0010894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 11/10/2022] [Accepted: 10/14/2022] [Indexed: 11/05/2022] Open
Abstract
CRISPR gene drives could revolutionize the control of infectious diseases by accelerating the spread of engineered traits that limit parasite transmission in wild populations. Gene drive technology in mollusks has received little attention despite the role of freshwater snails as hosts of parasitic flukes causing 200 million annual cases of schistosomiasis. A successful drive in snails must overcome self-fertilization, a common feature of host snails which could prevents a drive’s spread. Here we developed a novel population genetic model accounting for snails’ mixed mating and population dynamics, susceptibility to parasite infection regulated by multiple alleles, fitness differences between genotypes, and a range of drive characteristics. We integrated this model with an epidemiological model of schistosomiasis transmission to show that a snail population modification drive targeting immunity to infection can be hindered by a variety of biological and ecological factors; yet under a range of conditions, disease reduction achieved by chemotherapy treatment of the human population can be maintained with a drive. Alone a drive modifying snail immunity could achieve significant disease reduction in humans several years after release. These results indicate that gene drives, in coordination with existing public health measures, may become a useful tool to reduce schistosomiasis burden in selected transmission settings with effective CRISPR construct design and evaluation of the genetic and ecological landscape.
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Fogarty CE, Suwansa-ard S, Phan P, McManus DP, Duke MG, Wyeth RC, Cummins SF, Wang T. Identification of Putative Neuropeptides That Alter the Behaviour of Schistosoma mansoni Cercariae. BIOLOGY 2022; 11:biology11091344. [PMID: 36138823 PMCID: PMC9495596 DOI: 10.3390/biology11091344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/31/2022] [Accepted: 09/09/2022] [Indexed: 11/16/2022]
Abstract
Elucidating the infectivity of Schistosoma mansoni, one of the main etiological agents of human schistosomiasis, requires an improved understanding of the behavioural mechanisms of cercariae, the non-feeding mammalian infective stage. This study investigated the presence and effect of cercariae-derived putative neuropeptides on cercarial behaviour when applied externally. Cercariae were peptidomically analysed and 11 neuropeptide precursor proteins, all of which were specific to the Schistosoma genus and most of which highly expressed in the cercarial stage, were identified in cercariae for the first time. Protein–protein interaction analysis predicted the interaction of various neuropeptide precursors (e.g., Sm-npp-30, Sm-npp-33, Sm-npp-35) with cercarial structural proteins (e.g., myosin heavy chain and titin). In total, nine putative neuropeptides, selected based on their high hydrophobicity and small size (~1 kilodalton), were tested on cercariae (3 mg/mL) in acute exposure (1 min) and prolonged exposure (360 min) behavioural bioassays. The peptides AAYMDLPW-NH2, NRKIDQSFYSYY-NH2, FLLALPSP-OH, and NYLWDTRL-NH2 stimulated acute increases in cercarial spinning, stopping, and directional change during active states. However, only NRKIDQSFYSYY-NH2 caused the same behavioural changes at a lower concentration (0.1 mg/mL). After prolonged exposure, AAYMDLPW-NH2 and NYLWDTRL-NH2 caused increasing passive behaviour and NRKIDQSFYSYY-NH2 caused increasing body-first and head-pulling movements. These findings characterise behaviour-altering novel putative neuropeptides, which may inform future biocontrol innovations to prevent human schistosomiasis.
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Affiliation(s)
- Conor E. Fogarty
- Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
| | - Saowaros Suwansa-ard
- Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
| | - Phong Phan
- Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
| | - Donald P. McManus
- QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | - Mary G. Duke
- QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia
| | - Russell C. Wyeth
- Department of Biology, St. Francis Xavier University, Antigonish, NS B2G 2W5, Canada
| | - Scott F. Cummins
- Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
| | - Tianfang Wang
- Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4556, Australia
- Correspondence:
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6
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Oladipo EK, Jimah EM, Irewolede BA, Folakanmi EO, Olubodun OA, Adediran DA, Akintibubo SA, Odunlami FD, Olufemi SE, Ojo TO, Akinro OP, Hezekiah OS, Olayinka AT, Abiala GA, Idowu AF, Ogunniran JA, Ikuomola MO, Adegoke HM, Idowu UA, Akindiya OE, Oluwasanya GJ, Akanbi GM, Bamigboye FO, Aremu RO, Awobiyi HO, Kolapo KT, Oluwasegun JA, Olatunde SK, Adelusi TI. Immunoinformatics design of multi-epitope peptide for the diagnosis of Schistosoma haematobium infection. J Biomol Struct Dyn 2022:1-8. [DOI: 10.1080/07391102.2022.2111358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Elijah Kolawole Oladipo
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Laboratory of Molecular Biology, Bioinformatics and Immunology, Department of Microbiology, Adeleke University, Ede, Osun State, Nigeria
| | | | | | - Elizabeth Oluwatoyin Folakanmi
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Odunola Abimbola Olubodun
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Daniel Adewole Adediran
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Samuel Adebowale Akintibubo
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Foluso Daniel Odunlami
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Seun Elijah Olufemi
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Taiwo Ooreoluwa Ojo
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Omodamola Paulina Akinro
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Oluwaseun Samuel Hezekiah
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Adenike Titilayo Olayinka
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Grace Asegunloluwa Abiala
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Akindele Felix Idowu
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - James Akinwunmi Ogunniran
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Mary Omotoyinbo Ikuomola
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Hadijat Motunrayo Adegoke
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Laboratory of Computational and Biophysical Chemistry, Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Usman Abiodun Idowu
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Olawumi Elizabeth Akindiya
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Biology, Olusegun Agagu University of Science and Technology, Okiti-pupa, Ondo State, Nigeria
| | - Glory Jesudara Oluwasanya
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Laboratory of Molecular Biology, Bioinformatics and Immunology, Department of Microbiology, Adeleke University, Ede, Osun State, Nigeria
| | - Gideon Mayowa Akanbi
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | | | - Rasidat Oyindamola Aremu
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Laboratory of Molecular Biology, Bioinformatics and Immunology, Department of Microbiology, Adeleke University, Ede, Osun State, Nigeria
| | - Hezekiah Oluwajoba Awobiyi
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Laboratory of Molecular Biology, Bioinformatics and Immunology, Department of Microbiology, Adeleke University, Ede, Osun State, Nigeria
| | - Kehinde Temitope Kolapo
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Pure and Applied Biology, Microbiology Unit, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Jerry Ayobami Oluwasegun
- Genomics Unit, Helix Biogen Institute, Ogbomoso, Oyo State, Nigeria
- Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
| | - Simeon Kayowa Olatunde
- Department of Microbiology and Pathology, All Saints University School of Medicine, Roseau, Commonwealth of Dominica, West Indies
| | - Temitope Isaac Adelusi
- Computational Biology/Drug discovery laboratory, Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
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7
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Ouji Y, Hamasaki M, Misu M, Kitamura T, Hamano S, Yoshikawa M. Schistosoma mansoni larvae in vitro cultures using Biomphalaria glabrata extracts. Acta Trop 2022; 235:106636. [DOI: 10.1016/j.actatropica.2022.106636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 07/11/2022] [Accepted: 08/05/2022] [Indexed: 11/01/2022]
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8
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Comprehensive Risk Assessment of Schistosomiasis Epidemic Based on Precise Identification of Oncomelania hupensis Breeding Grounds-A Case Study of Dongting Lake Area. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041950. [PMID: 33671375 PMCID: PMC7923101 DOI: 10.3390/ijerph18041950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 11/16/2022]
Abstract
Spatio-temporal epidemic simulation, assessment, and risk monitoring serve as the core to establishing and improving the national public health emergency management system. In this study, we investigated Oncomelania hupensis breeding grounds and analyzed the locational and environmental preferences of snail breeding in Dongting Lake (DTL), Hunan, China. Using geographic information systems and remote sensing technology, we identified schistosomiasis risk areas and explored the factors affecting the occurrence and transmission of the disease. Several key conclusions were drawn. (1) From 2006 to 2016, the spatial change of potential O. hupensis breeding risk showed a diminishing trend from the eastern and northern regions to southwest DTL. Environmental changes in the eastern DTL region resulted in the lakeside and hydrophilic agglomerations of the O. hupensis populations. The shift in snail breeding grounds from a fragmented to centralized distribution indicates the weakening mobility of the O. hupensis population, the increasing independence of solitary groups, and the growing dependence of the snail population to the local environment. (2) The spatial risk distribution showed a descending gradient from west Dongting area to the east and an overall pattern of high in the periphery of large lakes and low in other areas. The cold-spot areas had their cores in Huarong County and Anxiang County and were scattered throughout the peripheral areas. The hot-spot areas had their center at Jinshi City, Nanxian County, and the southern part of Huarong County. The areas with increased comprehensive risks changed from centralized and large-scale development to fragmented shrinkage with increased partialization in the core area. The risk distribution's center shifted to the northwest. The spatial risk distribution exhibited enhanced concentricity along the major axis and increased dispersion along the minor axis.
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9
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Impact of seven years of mass drug administration and recrudescence of Schistosoma haematobium infections after one year of treatment gap in Zanzibar: Repeated cross-sectional studies. PLoS Negl Trop Dis 2021; 15:e0009127. [PMID: 33577601 PMCID: PMC7880478 DOI: 10.1371/journal.pntd.0009127] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/12/2021] [Indexed: 11/25/2022] Open
Abstract
Background Considerable progress towards the elimination of urogenital schistosomiasis was made by the Zanzibar Elimination of Schistosomiasis Transmission project from 2012 till 2016, when biannual praziquantel mass drug administration (MDA) alone or with additional snail control or behaviour change interventions were implemented. Annual MDA was continued in 2017 and 2018, but not in 2019, imposing a 16-month treatment gap. We monitored the Schistosoma haematobium prevalence from 2012 till 2020 and assessed recrudescence patterns with focus on 2020. Methodology Repeated cross-sectional surveys were conducted from 2011/12 till 2020 in 90 communities and 90 schools in Zanzibar. Annually, around 4,500 adults and up to 20,000 schoolchildren were surveyed. The S. haematobium prevalence was detected by urine filtration and reagent strips. In 2020, risk factors for infection were investigated using generalized estimated equation models. Principal findings In adults, the apparent S. haematobium prevalence was 3.9% in 2011 and 0.4% in 2020. In schoolchildren, the prevalence decreased from 6.6% in 2012 to 1.2% in 2019 with vicissitudes over the years. Prominent recrudescence of infection from 2.8% in 2019 to 9.1% (+225%) in 2020 was observed in 29 schools with historically moderate prevalences (≥10%). Compared with 2019, reinfection in 2020 was particularly striking in boys aged 9–16 years. Being male was a risk factor for infection in 2020 (adults: odds ratio (OR): 6.24, 95% confidence interval (95% CI): 1.96–19.60; schoolchildren: OR: 2.06, 95% CI: 1.52–2.78). Living near to a natural freshwater body significantly increased the odds of infection in adults (OR: 2.90, CI: 1.12–7.54). Conclusions/Significance After 11 rounds of MDA over 7 years and a 16-month treatment gap, the urogenital schistosomiasis prevalence considerably rebounded in hotspot areas. Future elimination efforts in Zanzibar should focus on re-intensifying MDA plus additional interventions in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted surveillance-response. Schistosomiasis is a neglected tropical disease caused by parasitic blood flukes of the genus Schistosoma. On the Zanzibar islands, United Republic of Tanzania, interventions to eliminate urogenital schistosomiasis commenced in 2012. From 2012 to 2016, the population was treated biannually with praziquantel and, additionally, some areas received mollusciciding against the intermediate host snail, or educational measures for behavior change. Mass drug administration (MDA) with praziquantel was continued annually in 2017 and 2018, but not in 2019. As a result of the interventions, the overall S. haematobium prevalence was reduced to 0.4% in adults and 3.4% in schoolchildren in 2020. However, in some areas, the MDA gap in 2019 resulted in a considerable rebound of infections. The recrudescence in 2020 was particularly striking for boys aged 9–16 years. In general, in 2020, male participants had higher odds of infection than females. Adults living near to a natural freshwater body also showed an increased risk of S. haematobium infection. Future elimination efforts in Zanzibar should focus on re-intensifying elimination interventions, including MDA, snail control and behavior change in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted interventions, such as surveillance-response.
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10
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Yang X, Zhang Q, Ma L, Sun QX, Liang S, Zhou JX. Afforestation suppresses Oncomelania hupensis snail density through influencing algae in beaches of the Dongting Lake. PLoS Negl Trop Dis 2021; 15:e0009100. [PMID: 33539386 PMCID: PMC7888596 DOI: 10.1371/journal.pntd.0009100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 02/17/2021] [Accepted: 01/04/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Oncomelania snails serve as the sole intermediate host for Schistosoma japonicum, one of the most important neglected tropical diseases in the world. Afforestation suppression of the Oncomelania hupensis snail has been a long-term effective national strategy to decrease snail density in China. Many previous studies have made clear that vegetation (biotic factors) and soil (abiotic factors) were the basic requirements for snail survival on beaches. Moreover, a lot of research on snail control has been focused on the specific influencing environmental factors for snail survival, such as the vegetation community structure, species composition, diversity index, and the physical and chemical properties of the soil. Most of the existing research has studied the influence of a single factor on snail population density. Conversely, there have been only a few studies focused on the food sources and food composition of the snails. The current research situation on snail control has indicated that the mechanisms underlying ecological snail control have not been systematically characterized. The question of whether biotic or abiotic factors were more important in influencing snail survival remains unclear. Afforestation on beaches has significantly suppressed snail density in China so far. In this study, we proposed that the reduction of snail density was not affected by a single factor but by the interactions of multiple related factors introduced by afforestation. Moreover, different biotic and abiotic factors have significantly different effects on snail control. Therefore the goal of this study was to evaluate the relative importance and interactions of related biotic and abiotic factors on snail density. Methods: Four major vegetation communities: Sedge, Reed, Artificial poplar (3 years of age) and Artificial poplar (5 years of age), on the beaches of the Yangtze River in China were selected for vegetation and snail surveys, as well as for soil sampling. Structural Equation Model (SEM) analysis was used to assess the interactions of biotic and abiotic factors in the context of snail ecology. The soil properties were considered as abiotic factors, while algae of Chlorophyta, Cyanophyta and Bacillariophyta phyla were considered to be biotic factors. In the path analysis, the total effect between the variables was the sum of the direct and indirect effects. RESULTS The snail density had significant correlations with soil properties, such as water content, bulk density, capillary porosity and pH value, as well as with all three types of soil algae, Chlorophyta, Cyanophyta, and Bacillariophyta. Snail density had a direct negative relationship with capillary porosity and soil bulk density, an indirect negative relationship with soil pH value and an indirect positive relationship with soil water content via soil algae. Meanwhile, as an important food source for the snail, the Chlorophyta, Cyanophyta and Bacillariophyta algae had a significant positive correlation with snail density. High soil pH had a negative impact on Chlorophyta, Bacillariophyta, while soil water content had a positive impact on Chlorophyta, and soil bulk density had a negative impact on Cyanophyta. In addition, the soil pH value and soil bulk density both had negative correlations with soil water content. CONCLUSION Afforestation of the beach environment can significantly reduce the snail population density by altering ecological factors. Soil algae (biological factors) might be the key element that drives ecological snail control. As important habitat determinants, the impact of the properties of the soil (non-biological factors) on the snail population was largely mediated through soil algae.
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Affiliation(s)
- Xiao Yang
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Academy of Forest Inventory and Planning, National Forestry and Grassland Administration, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing, China
- Engineering Research Center of Forestry Ecological Engineering, Ministry of Education, Beijing, China
| | - Qian Zhang
- Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Li Ma
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing, China
- Engineering Research Center of Forestry Ecological Engineering, Ministry of Education, Beijing, China
| | - Qi-Xiang Sun
- Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Song Liang
- Department of Environmental and Global Health, College of Public Health and Health Professions, and Emerging Pathogens Institute, University of Florida, Gainesville, Florida United States of America
| | - Jin-Xing Zhou
- School of Soil and Water Conservation, Beijing Forestry University, Beijing, China
- Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing, China
- Engineering Research Center of Forestry Ecological Engineering, Ministry of Education, Beijing, China
- * E-mail:
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11
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Huang Q, Gurarie D, Ndeffo-Mbah M, Li E, King CH. Schistosoma transmission in a dynamic seasonal environment and its impact on the effectiveness of disease control. J Infect Dis 2020; 225:1050-1061. [PMID: 33263735 PMCID: PMC8921996 DOI: 10.1093/infdis/jiaa746] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND A seasonal transmission environment including seasonal variation of snail population density and human-snail contact patterns can affect the dynamics of Schistosoma infection and the success of control interventions. In projecting control outcomes, conventional modeling approaches have often ignored seasonality by using simplified intermediate-host modeling, or by restricting seasonal effects through use of yearly averaging. METHODS We used mathematical analysis and numerical simulation to estimate the impact of seasonality on disease dynamics and control outcomes, and to evaluate whether seasonal averaging or intermediate-host reduction can provide reliable predictions of control outcomes. We also examined whether seasonality could be used as leverage in creation of effective control strategies. RESULTS We found models that used seasonal averaging could grossly overestimate infection burden and underestimate control outcomes in highly seasonal environments. We showed that proper intra-seasonal timing of control measures could make marked improvement on the long-term burden reduction for Schistosoma transmission control, and we identified the optimal timing for each intervention. Seasonal snail control, implemented alone, was less effective than mass drug administration, but could provide additive impact in reaching control and elimination targets. CONCLUSION Seasonal variation makes Schistosoma transmission less sustainable and easier to control than predicted by earlier modeling studies.
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Affiliation(s)
- Qimin Huang
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, USA
| | - David Gurarie
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, USA.,Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, USA
| | - Martial Ndeffo-Mbah
- Department of Veterinary and Integrative Biosciences, College of Veterinary and Biomedical Sciences, Texas A&M University, College Station, USA.,School of Public Health, Texas A&M University, College Station, USA
| | - Emily Li
- Ascension St. Vincent Indianapolis, Family Medicine Residency, Indianapolis, USA
| | - Charles H King
- Center for Global Health and Diseases, School of Medicine, Case Western Reserve University, Cleveland, USA.,Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, USA.,WHO Collaborating Centre for Research and Training for Schistosomiasis Elimination, Cleveland, USA
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12
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King CH, Yoon N, Wang X, Lo NC, Alsallaq R, Ndeffo-Mbah M, Li E, Gurarie D. Application of Schistosomiasis Consortium for Operational Research and Evaluation Study Findings to Refine Predictive Modeling of Schistosoma mansoni and Schistosoma haematobium Control in Sub-Saharan Africa. Am J Trop Med Hyg 2020; 103:97-104. [PMID: 32400357 PMCID: PMC7351296 DOI: 10.4269/ajtmh.19-0852] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
An essential mission of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was to help inform global health practices related to the control and elimination of schistosomiasis. To provide more accurate, evidence-based projections of the most likely impact of different control interventions, whether implemented alone or in combination, SCORE supported mathematical modeling teams to provide simulations of community-level Schistosoma infection outcomes in the setting of real or hypothetical programs implementing multiyear mass drug administration (MDA) for parasite control. These models were calibrated using SCORE experience with Schistosoma mansoni and Schistosoma haematobium gaining and sustaining control studies, and with data from comparable programs that used community-based or school-based praziquantel MDA in other parts of sub-Saharan Africa. From 2010 to 2019, models were developed and refined, first to project the likely SCORE control outcomes, and later to more accurately reflect impact of MDA across different transmission settings, including the role of snail ecology and the impact of seasonal rainfall on snail abundance. Starting in 2014, SCORE modeling projections were also compared with the models of colleagues in the Neglected Tropical Diseases Modelling Consortium. To explore further possible improvement to program-based control, later simulations examined the cost-effectiveness of combining MDA with environmental snail control, and the utility of early impact assessment to more quickly identify persistent hot spots of transmission. This article provides a nontechnical summary of the 11 SCORE-related modeling projects and provides links to the original open-access articles describing model development and projections relevant to schistosomiasis control policy.
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Affiliation(s)
- Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nara Yoon
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, Ohio
| | - Xiaoxia Wang
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, Ohio
| | - Nathan C Lo
- Department of Medicine, University of California, San Francisco, San Francisco, California
| | - Ramzi Alsallaq
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | | | - Emily Li
- School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - David Gurarie
- Department of Mathematics, Applied Mathematics and Statistics, Case Western Reserve University, Cleveland, Ohio.,Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
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13
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Hoover CM, Sokolow SH, Kemp J, Sanchirico JN, Lund AJ, Jones IJ, Higginson T, Riveau G, Savaya A, Coyle S, Wood CL, Micheli F, Casagrandi R, Mari L, Gatto M, Rinaldo A, Perez-Saez J, Rohr JR, Sagi A, Remais JV, De Leo GA. Modelled effects of prawn aquaculture on poverty alleviation and schistosomiasis control. NATURE SUSTAINABILITY 2020; 2:611-620. [PMID: 33313425 PMCID: PMC7731924 DOI: 10.1038/s41893-019-0301-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 04/26/2019] [Indexed: 05/23/2023]
Abstract
Recent evidence suggests that snail predators may aid efforts to control the human parasitic disease schistosomiasis by eating aquatic snail species that serve as intermediate hosts of the parasite. Potential synergies between schistosomiasis control and aquaculture of giant prawns are evaluated using an integrated bio-economic-epidemiologic model. Combinations of stocking density and aquaculture cycle length that maximize cumulative, discounted profit are identified for two prawn species in sub-Saharan Africa: the endemic, non-domesticated Macrobrachium vollenhovenii, and the non-native, domesticated Macrobrachium rosenbergii. At profit maximizing densities, both M. rosenbergii and M. vollenhovenii may substantially reduce intermediate host snail populations and aid schistosomiasis control efforts. Control strategies drawing on both prawn aquaculture to reduce intermediate host snail populations and mass drug administration to treat infected individuals are found to be superior to either strategy alone. Integrated aquaculture-based interventions can be a win-win strategy in terms of health and sustainable development in schistosomiasis endemic regions of the world.
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Affiliation(s)
- Christopher M. Hoover
- Division of Environmental Health Sciences, University of California, Berkeley School of Public Health, Berkeley, CA 94720 USA
| | - Susanne H. Sokolow
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
- Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA 94305 USA
| | - Jonas Kemp
- Program in Human Biology, Stanford University, Stanford, CA 94305 USA
| | - James N. Sanchirico
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616 USA
| | - Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, School of Earth, Energy and Environmental Sciences, Stanford University, Stanford, CA 94305 USA
| | - Isabel J. Jones
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
| | - Tyler Higginson
- Middlebury Institute of International Studies at Monterey, Monterey, CA 93940 USA
| | - Gilles Riveau
- Biomedical Research Center EPLS, Saint Louis, Senegal
| | - Amit Savaya
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Shawn Coyle
- Kentucky State University, Aquaculture Division, Aquaculture Research Center, Frankfort, KY 40601 USA
| | - Chelsea L. Wood
- University of Washington, School of Aquatic and Fishery Sciences, Seattle, WA 98195 USA
| | - Fiorenza Micheli
- Hopkins Marine Station and Center for Ocean Solutions, Stanford University, Pacific Grove, CA 93950 USA
| | - Renato Casagrandi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Lorenzo Mari
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Marino Gatto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milano, Italy
| | - Andrea Rinaldo
- Laboratory of Ecohydrology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Switzerland
| | - Javier Perez-Saez
- Laboratory of Ecohydrology, School of Architecture, Civil and Environmental Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Switzerland
| | - Jason R. Rohr
- Department of Biological Sciences, Eck Institute of Global Health, Environmental Change Initiative University of Notre Damea, Notre Dame, IN, 46556 USA
- Department of Integrative Biology, University of South Florida, Tampa, FL, 33620 USA
| | - Amir Sagi
- Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Justin V. Remais
- Division of Environmental Health Sciences, University of California, Berkeley School of Public Health, Berkeley, CA 94720 USA
| | - Giulio A. De Leo
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950 USA
- Woods Institute for the Environment and Center for Innovation in Global Health, Stanford University, Stanford, CA 94305 USA
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14
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Li EY, Gurarie D, Lo NC, Zhu X, King CH. Improving public health control of schistosomiasis with a modified WHO strategy: a model-based comparison study. LANCET GLOBAL HEALTH 2020; 7:e1414-e1422. [PMID: 31537371 PMCID: PMC7024988 DOI: 10.1016/s2214-109x(19)30346-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 07/08/2019] [Accepted: 07/18/2019] [Indexed: 01/19/2023]
Abstract
Background Schistosomiasis is endemic in many low-income and middle-income countries. To reduce infection-associated morbidity, WHO has published guidelines for control of schistosomiasis based on targeted mass drug administration (MDA) and, in 2017, on supplemental snail control. We compared the current WHO guideline-based strategies from 2012 to an alternative, adaptive decision making framework for control in heterogeneous environments, to estimate their predicted relative effectiveness and time to achievement of defined public health goals. Methods In this model-based comparison study, we adapted an established transmission model for Schistosoma infection that couples local human and snail populations and includes aspects of snail ecology and parasite biology. We calibrated the model using data from high-risk, moderate-risk, and lower-risk rural villages in Kenya, and then simulated control via MDA. We compared 2012 WHO guidelines with a modified adaptive strategy that tested a lower-prevalence threshold for MDA and shorter intervals between implementation, evaluation, and modification. We also explored the addition of snail control to this modified strategy. The primary outcomes were the proportion of simulations that achieved the WHO targets in children aged 5–14 years of less than 5% (2020 morbidity control goal) and less than 1% (2025 elimination as a public health problem goal) heavy infection and the mean duration of treatment required to achieve these goals. Findings In high-risk communities (80% baseline prevalence), current WHO strategies for MDA were not predicted to achieve morbidity control (<5% prevalence of heavy infections) in 80% of simulations over a 10-year period, whereas the modified adaptive strategy was predicted to achieve this goal in over 50% of simulations within 5 years. In low-risk and moderate-risk communities, current WHO guidelines from 2012 were predicted to achieve morbidity control in most simulations (96% in low-risk and 41% for moderate-risk), although the proposed adaptive strategy reached this goal in a shorter period (mean reduction of 5 years). The model predicted that the addition of snail control to the proposed adaptive strategy would achieve morbidity control in all high-risk communities, and 54% of communities could reach the goal for elimination as a public health problem (<1% heavy infection) within 7 years. Interpretation The modified adaptive decision making framework is predicted to be more effective than the current WHO guidelines in reaching 2025 public health goals, especially for high-prevalence regions. Modifications in current guidelines could reduce the time and resources needed for countries who are currently working on achieving public health goals against schistosomiasis. Funding University of Georgia Research Foundation, The Bill & Melinda Gates Foundation, and the Medical Scientist Training Program at Stanford University School of Medicine.
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Affiliation(s)
- Emily Y Li
- School of Medicine, Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA.
| | - David Gurarie
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, Cleveland, OH, USA
| | - Nathan C Lo
- Department of Medicine, University of California, San Francisco, San Francisco, CA, USA
| | - Xuewei Zhu
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, Cleveland, OH, USA
| | - Charles H King
- School of Medicine, Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
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15
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Walker JW, Kittur N, Binder S, Castleman JD, Drake JM, Campbell CH, King CH, Colley DG. Environmental Predictors of Schistosomiasis Persistent Hotspots following Mass Treatment with Praziquantel. Am J Trop Med Hyg 2020; 102:328-338. [PMID: 31889506 PMCID: PMC7008331 DOI: 10.4269/ajtmh.19-0658] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Schistosomiasis control programs rely heavily on mass drug administration (MDA) campaigns with praziquantel for preventative chemotherapy. Areas where the prevalence and/or intensity of schistosomiasis infection remains high even after several rounds of treatment, termed "persistent hotspots" (PHSs), have been identified in trials of MDA effectiveness conducted by the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) in Kenya, Mozambique, Tanzania, and Côte d'Ivoire. In this analysis, we apply a previously developed set of criteria to classify the PHS status of 531 study villages from five SCORE trials. We then fit logistic regression models to data from SCORE and publically available georeferenced datasets to evaluate the influence of local environmental and population features, pre-intervention infection burden, and treatment scheduling on PHS status in each trial. The frequency of PHS in individual trials ranged from 35.3% to 71.6% in study villages. Significant relationships between PHS status and MDA frequency, distance to freshwater, rainfall, baseline schistosomiasis burden, elevation, land cover type, and village remoteness were each observed in at least one trial, although the strength and direction of these relationships was not always consistent among study sites. These findings suggest that PHSs are driven in part by environmental conditions that modify the risk and frequency of reinfection.
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Affiliation(s)
- Joseph W Walker
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, Georgia.,University of Georgia College of Public Health, Athens, Georgia
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Jennifer D Castleman
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - John M Drake
- Odum School of Ecology, University of Georgia, Athens, Georgia.,Center for the Ecology of Infectious Disease, University of Georgia, Athens, Georgia
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia
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16
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Strahan R, McAdam D, Paul E. Change in schistosomiasis-related liver disease with repeated praziquantel treatment in school children in rural Zambia. Trop Doct 2020; 50:216-221. [PMID: 32356671 DOI: 10.1177/0049475520921281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Repeated praziquantel treatment for schistosomiasis is an effective method to reduce disease burden. Ultrasonographic methods were used to assess the severity of schistosoma mansoni-related liver disease and demonstrate improvement following treatment. We compared data from 733 children in 2010 and 972 children in 2018 to determine the effect of repeated praziquantel treatment on prevalence of liver disease. Three age groups were compared across three liver disease classifications (normal, mild, severe). From 2010 to 2018, there was a significant reduction in prevalence of severe liver disease in all age groups (P = 0.03 for 5-10 years, P < 0.001 for 11-15 years and 16-20 years). In both male and female students, the proportion having a normal liver significantly increased (P < 0.001) from 2010 to 2018, in the 11-15-year-olds and 16-20-year-olds, demonstrating that liver disease significantly reduced in these age groups. This study demonstrates a reduction in schistosomiasis-related morbidity with repeated praziquantel treatment.
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Affiliation(s)
- Rodney Strahan
- Radiology, Chitokoloki Mission Hospital, Chitokoloki, North Western Province, Zambia
| | - David McAdam
- Medical Director, Chitokoloki Mission Hospital, Chitokoloki, North Western Province, Zambia
| | - Eldho Paul
- Monash Centre for Health Research and Implementation, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia
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17
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Castillo MG, Humphries JE, Mourão MM, Marquez J, Gonzalez A, Montelongo CE. Biomphalaria glabrata immunity: Post-genome advances. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 104:103557. [PMID: 31759924 PMCID: PMC8995041 DOI: 10.1016/j.dci.2019.103557] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 11/11/2019] [Accepted: 11/16/2019] [Indexed: 06/10/2023]
Abstract
The freshwater snail, Biomphalaria glabrata, is an important intermediate host in the life cycle for the human parasite Schistosoma mansoni, the causative agent of schistosomiasis. Current treatment and prevention strategies have not led to a significant decrease in disease transmission. However, the genome of B. glabrata was recently sequenced to provide additional resources to further our understanding of snail biology. This review presents an overview of recently published, post-genome studies related to the topic of snail immunity. Many of these reports expand on findings originated from the genome characterization. These novel studies include a complementary gene linkage map, analysis of the genome of the B. glabrata embryonic (Bge) cell line, as well as transcriptomic and proteomic studies looking at snail-parasite interactions and innate immune memory responses towards schistosomes. Also included are biochemical investigations on snail pheromones, neuropeptides, and attractants, as well as studies investigating the frontiers of molluscan epigenetics and cell signaling were also included. Findings support the current hypotheses on snail-parasite strain compatibility, and that snail host resistance to schistosome infection is dependent not only on genetics and expression, but on the ability to form multimeric molecular complexes in a timely and tissue-specific manner. The relevance of cell immunity is reinforced, while the importance of humoral factors, especially for secondary infections, is supported. Overall, these studies reflect an improved understanding on the diversity, specificity, and complexity of molluscan immune systems.
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Affiliation(s)
- Maria G Castillo
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA.
| | | | - Marina M Mourão
- Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, Fiocruz Minas, Brazil
| | - Joshua Marquez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Adrian Gonzalez
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | - Cesar E Montelongo
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
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18
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Becker JM, Ganatra AA, Kandie F, Mühlbauer L, Ahlheim J, Brack W, Torto B, Agola EL, McOdimba F, Hollert H, Fillinger U, Liess M. Pesticide pollution in freshwater paves the way for schistosomiasis transmission. Sci Rep 2020; 10:3650. [PMID: 32107456 PMCID: PMC7046736 DOI: 10.1038/s41598-020-60654-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 02/14/2020] [Indexed: 12/19/2022] Open
Abstract
Schistosomiasis is a severe neglected tropical disease caused by trematodes and transmitted by freshwater snails. Snails are known to be highly tolerant to agricultural pesticides. However, little attention has been paid to the ecological consequences of pesticide pollution in areas endemic for schistosomiasis, where people live in close contact with non-sanitized freshwaters. In complementary laboratory and field studies on Kenyan inland areas along Lake Victoria, we show that pesticide pollution is a major driver in increasing the occurrence of host snails and thus the risk of schistosomiasis transmission. In the laboratory, snails showed higher insecticide tolerance to commonly found pesticides than associated invertebrates, in particular to the neonicotinoid Imidacloprid and the organophosphate Diazinon. In the field, we demonstrated at 48 sites that snails were present exclusively in habitats characterized by pesticide pollution and eutrophication. Our analysis revealed that insensitive snails dominated over their less tolerant competitors. The study shows for the first time that in the field, pesticide concentrations considered “safe” in environmental risk assessment have indirect effects on human health. Thus we conclude there is a need for rethinking the environmental risk of low pesticide concentrations and of integrating agricultural mitigation measures in the control of schistosomiasis.
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Affiliation(s)
- Jeremias M Becker
- Helmholtz Centre for Environmental Research - UFZ, Department System-Ecotoxicology, Permoserstrasse 15, 04318, Leipzig, Germany.,RWTH Aachen University, Department of Ecosystem Analysis, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany
| | - Akbar A Ganatra
- International Centre of Insect Physiology and Ecology (icipe), Human Health department, P.O. Box 30772-00100, Nairobi, Kenya. .,Egerton University, Biological sciences, P.O Box 536-20115, Njoro, Kenya.
| | - Faith Kandie
- RWTH Aachen University, Department of Ecosystem Analysis, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany.,International Centre of Insect Physiology and Ecology (icipe), Human Health department, P.O. Box 30772-00100, Nairobi, Kenya
| | - Lina Mühlbauer
- Helmholtz Centre for Environmental Research - UFZ, Department System-Ecotoxicology, Permoserstrasse 15, 04318, Leipzig, Germany.,Ruprecht-Karl-University of Heidelberg, Faculty of Biosciences, Im Neuenheimer Feld 234, 69120, Heidelberg, Germany
| | - Jörg Ahlheim
- Helmholtz Centre for Environmental Research - UFZ, Department System-Ecotoxicology, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Werner Brack
- Helmholtz Centre for Environmental Research - UFZ, Department System-Ecotoxicology, Permoserstrasse 15, 04318, Leipzig, Germany.,RWTH Aachen University, Department of Ecosystem Analysis, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany
| | - Baldwyn Torto
- International Centre of Insect Physiology and Ecology (icipe), Human Health department, P.O. Box 30772-00100, Nairobi, Kenya
| | - Eric L Agola
- Centre for Biotechnology Research and Development, Kenya Medical Research institute (KEMRI), P.O. Box 54840-00200, Nairobi, Kenya.,The Technical University of Kenya, P.O. Box 52428-00200, Nairobi, Kenya
| | - Francis McOdimba
- International Centre of Insect Physiology and Ecology (icipe), Human Health department, P.O. Box 30772-00100, Nairobi, Kenya.,Egerton University, Biological sciences, P.O Box 536-20115, Njoro, Kenya
| | - Henner Hollert
- RWTH Aachen University, Department of Ecosystem Analysis, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany.,Department Evolutionary Ecology and Environmental Toxicology, Institute of Ecology, Evolution and Diversity, Faculty Biological Sciences, Goethe University Frankfurt, Frankfurt, 60438, Germany
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (icipe), Human Health department, P.O. Box 30772-00100, Nairobi, Kenya.
| | - Matthias Liess
- Helmholtz Centre for Environmental Research - UFZ, Department System-Ecotoxicology, Permoserstrasse 15, 04318, Leipzig, Germany. .,RWTH Aachen University, Department of Ecosystem Analysis, Institute for Environmental Research, Worringerweg 1, 52074, Aachen, Germany.
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19
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Buck JC, De Leo GA, Sokolow SH. Concomitant Immunity and Worm Senescence May Drive Schistosomiasis Epidemiological Patterns: An Eco-Evolutionary Perspective. Front Immunol 2020; 11:160. [PMID: 32161583 PMCID: PMC7053360 DOI: 10.3389/fimmu.2020.00160] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/21/2020] [Indexed: 11/13/2022] Open
Abstract
In areas where human schistosomiasis is endemic, infection prevalence and egg output are known to rise rapidly through childhood, reach a peak at 8-15 years of age, and decline thereafter. A similar peak ("overshoot") followed by return to equilibrium infection levels sometimes occurs a year or less after mass drug administration. These patterns are usually assumed to be due to acquired immunity, which is induced by exposure, directed by the host's immune system, and develops slowly over the lifetime of the host. Other explanations that have been advanced previously include differential exposure of hosts, differential mortality of hosts, and progressive pathology. Here we review these explanations and offer a novel (but not mutually exclusive) explanation, namely that adult worms protect the host against larval stages for their own benefit ("concomitant immunity") and that worm fecundity declines with worm age ("reproductive senescence"). This explanation approaches schistosomiasis from an eco-evolutionary perspective, as concomitant immunity maximizes the fitness of adult worms by reducing intraspecific competition within the host. If correct, our hypothesis could have profound implications for treatment and control of human schistosomiasis. Specifically, if immunity is worm-directed, then treatment of long-standing infections comprised of old senescent worms could enable infection with new, highly fecund worms. Furthermore, our hypothesis suggests revisiting research on therapeutics that mimic the concomitant immunity-modulating activity of adult worms, while minimizing pathological consequences of their eggs. We emphasize the value of an eco-evolutionary perspective on host-parasite interactions.
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Affiliation(s)
- Julia C. Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States
| | - Susanne H. Sokolow
- Department of Biology, Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States
- Woods Institute for the Environment, Stanford University, Stanford, CA, United States
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20
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Wood CL, Sokolow SH, Jones IJ, Chamberlin AJ, Lafferty KD, Kuris AM, Jocque M, Hopkins S, Adams G, Buck JC, Lund AJ, Garcia-Vedrenne AE, Fiorenza E, Rohr JR, Allan F, Webster B, Rabone M, Webster JP, Bandagny L, Ndione R, Senghor S, Schacht AM, Jouanard N, Riveau G, De Leo GA. Precision mapping of snail habitat provides a powerful indicator of human schistosomiasis transmission. Proc Natl Acad Sci U S A 2019; 116:23182-23191. [PMID: 31659025 PMCID: PMC6859407 DOI: 10.1073/pnas.1903698116] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Recently, the World Health Organization recognized that efforts to interrupt schistosomiasis transmission through mass drug administration have been ineffective in some regions; one of their new recommended strategies for global schistosomiasis control emphasizes targeting the freshwater snails that transmit schistosome parasites. We sought to identify robust indicators that would enable precision targeting of these snails. At the site of the world's largest recorded schistosomiasis epidemic-the Lower Senegal River Basin in Senegal-intensive sampling revealed positive relationships between intermediate host snails (abundance, density, and prevalence) and human urogenital schistosomiasis reinfection (prevalence and intensity in schoolchildren after drug administration). However, we also found that snail distributions were so patchy in space and time that obtaining useful data required effort that exceeds what is feasible in standard monitoring and control campaigns. Instead, we identified several environmental proxies that were more effective than snail variables for predicting human infection: the area covered by suitable snail habitat (i.e., floating, nonemergent vegetation), the percent cover by suitable snail habitat, and size of the water contact area. Unlike snail surveys, which require hundreds of person-hours per site to conduct, habitat coverage and site area can be quickly estimated with drone or satellite imagery. This, in turn, makes possible large-scale, high-resolution estimation of human urogenital schistosomiasis risk to support targeting of both mass drug administration and snail control efforts.
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Affiliation(s)
- Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195;
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
| | - Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
| | | | - Kevin D Lafferty
- Western Ecological Research Center, United States Geological Survey, Santa Barbara, CA 93106
- Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Armand M Kuris
- Marine Science Institute, University of California, Santa Barbara, CA 93106
| | - Merlijn Jocque
- Aquatic and Terrestrial Ecology, Royal Belgian Institute of Natural Sciences, 1000 Brussels, Belgium
| | - Skylar Hopkins
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Grant Adams
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195
| | - Julia C Buck
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, NC 28403
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, CA 94305
| | - Ana E Garcia-Vedrenne
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095
| | - Evan Fiorenza
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195
| | - Jason R Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, IN 46556
| | - Fiona Allan
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Bonnie Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Muriel Rabone
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London SW7 5BD, United Kingdom
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
| | - Joanne P Webster
- London Centre for Neglected Tropical Disease Research, Imperial College London School of Public Health, London W2 1PG, United Kingdom
- Centre for Emerging, Endemic, and Exotic Diseases, Department of Pathology and Population Sciences, Royal Veterinary College, University of London, London NW1 0TU, United Kingdom
| | - Lydie Bandagny
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Raphaël Ndione
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Simon Senghor
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Anne-Marie Schacht
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Nicolas Jouanard
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
- Station d'Innovation Aquacole, BP 524 Saint-Louis, Senegal
| | - Gilles Riveau
- Biomedical Research Center Espoir Pour La Santé, BP 226 Saint-Louis, Senegal
| | - Giulio A De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950
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21
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Rabone M, Wiethase JH, Allan F, Gouvras AN, Pennance T, Hamidou AA, Webster BL, Labbo R, Emery AM, Garba AD, Rollinson D. Freshwater snails of biomedical importance in the Niger River Valley: evidence of temporal and spatial patterns in abundance, distribution and infection with Schistosoma spp. Parasit Vectors 2019; 12:498. [PMID: 31640811 PMCID: PMC6805334 DOI: 10.1186/s13071-019-3745-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 10/09/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Sound knowledge of the abundance and distribution of intermediate host snails is key to understanding schistosomiasis transmission and to inform effective interventions in endemic areas. METHODS A longitudinal field survey of freshwater snails of biomedical importance was undertaken in the Niger River Valley (NRV) between July 2011 and January 2016, targeting Bulinus spp. and Biomphalaria pfeifferi (intermediate hosts of Schistosoma spp.), and Radix natalensis (intermediate host of Fasciola spp.). Monthly snail collections were carried out in 92 sites, near 20 localities endemic for S. haematobium. All bulinids and Bi. pfeifferi were inspected for infection with Schistosoma spp., and R. natalensis for infection with Fasciola spp. RESULTS Bulinus truncatus was the most abundant species found, followed by Bulinus forskalii, R. natalensis and Bi. pfeifferi. High abundance was associated with irrigation canals for all species with highest numbers of Bulinus spp. and R. natalensis. Seasonality in abundance was statistically significant in all species, with greater numbers associated with dry season months in the first half of the year. Both B. truncatus and R. natalensis showed a negative association with some wet season months, particularly August. Prevalences of Schistosoma spp. within snails across the entire study were as follows: Bi. pfeifferi: 3.45% (79/2290); B. truncatus: 0.8% (342/42,500); and B. forskalii: 0.2% (24/11,989). No R. natalensis (n = 2530) were infected. Seasonality of infection was evident for B. truncatus, with highest proportions shedding in the middle of the dry season and lowest in the rainy season, and month being a significant predictor of infection. Bulinus spp. and Bi. pfeifferi showed a significant correlation of snail abundance with the number of snails shedding. In B. truncatus, both prevalence of Schistosoma spp. infection, and abundance of shedding snails were significantly higher in pond habitats than in irrigation canals. CONCLUSIONS Evidence of seasonality in both overall snail abundance and infection with Schistosoma spp. in B. truncatus, the main intermediate host in the region, has significant implications for monitoring and interrupting transmission of Schistosoma spp. in the NRV. Monthly longitudinal surveys, representing intensive sampling effort have provided the resolution needed to ascertain both temporal and spatial trends in this study. These data can inform planning of interventions and treatment within the region.
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Affiliation(s)
- Muriel Rabone
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Joris Hendrik Wiethase
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Anouk Nathalie Gouvras
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Tom Pennance
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
- School of Biosciences, Cardiff University, Cardiff, CF10 3AT UK
| | - Amina Amadou Hamidou
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
| | - Bonnie Lee Webster
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Rabiou Labbo
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
- Centre de Recherche Médicale et Sanitaire (CERMES), Institut Pasteur International Network, 634 Bd de la Nation, BP 10887, Niamey, Niger
| | - Aidan Mark Emery
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
| | - Amadou Djirmay Garba
- Réseau International Schistosomoses, Environnement Aménagement et Lutte (RISEAL-Niger), 333, Avenue des Zarmakoye, B.P. 13724, Niamey, Niger
- World Health Organization, Geneva, Switzerland
| | - David Rollinson
- Department of Life Sciences, Natural History Museum, Cromwell Rd, South Kensington, London, SW7 5BD UK
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22
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Nelwan ML. Schistosomiasis: Life Cycle, Diagnosis, and Control. Curr Ther Res Clin Exp 2019; 91:5-9. [PMID: 31372189 PMCID: PMC6658823 DOI: 10.1016/j.curtheres.2019.06.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 06/06/2019] [Indexed: 12/20/2022] Open
Abstract
Three main schistosomiasis species can infect humans; S. haematobium, S. japonicum, and S. mansoni. The parasites life cycle includes two kind of reproduction; asexual reproduction in snails and sexual reproduction in mammals. Multiple diagnostic techniques are used. Currently praziquantel is the only drug therapy approved for control of schistosomiasis but other promising candidate drugs (e.g. SpAE, and ruthenium compounds) are being tested. A number of vaccine candidates exist including SmCB1, SjAChE, and SmCB. Genetic manipulations are being investigated.
Background Human schistosomiasis is a parasitic disease caused by blood-worms that infect multiple organs, including the liver, intestine, bladder, and urethra. This disease may be eliminated with Praziquantel, vaccines, and gene therapy. Aims In this review, the author describes the progress in a study of schistosomiasis that focused on the life cycle, diagnosis, and control. Methodology The author searched the PubMed Database at NCBI for articles on schistosomiasis published between 2014 and 2018. All articles were open access and in English. Results The life cycle of this parasites involve two hosts: snails and mammals. Manifestations of schistosomiasis can be acute or chronic. Clinical manifestations of acute schistosomiasis can include fever and headache. Symptoms of chronic infections can include dysuria and hyperplasia. Infection can occur in several sites including the bile ducts, intestine, and bladder. The different sites of infection and symptoms seen are related to which of the species involved. Five species can infect humans. The three most commons are S. haematobium, S. japonicum, and S. mansoni. Detection tools for people with schistosomiasis can include the Kato-Katz and PCR. Praziquantel is at present the only effective treatment of this disease. In the future, vaccination or gene therapy may be used. Conclusion Kato-Katz and PCR are tools for detecting schistosomiasis on humans. Praziquantel, diagnosis, vaccines, and gene therapy are useful methods for eliminating schistosomiasis.
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Affiliation(s)
- Martin L. Nelwan
- Address correspondence to: Department of Animal Science, Nelwan Institution for Human Resource Development, Jl A Yani No. 24, Palu, Indonesia.
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23
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Niu Y, Li R, Qiu J, Xu X, Huang D, Shao Q, Cui Y. Identifying and Predicting the Geographical Distribution Patterns of Oncomelania hupensis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16122206. [PMID: 31234446 PMCID: PMC6616429 DOI: 10.3390/ijerph16122206] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/11/2019] [Accepted: 06/18/2019] [Indexed: 11/16/2022]
Abstract
Schistosomiasis is a snail-borne parasitic disease endemic to the tropics and subtropics, whose distribution depends on snail prevalence as determined by climatic and environmental factors. Here, dynamic spatial and temporal patterns of Oncomelania hupensis distributions were quantified using general statistics, global Moran’s I, and standard deviation ellipses, with Maxent modeling used to predict the distribution of habitat areas suitable for this snail in Gong’an County, a severely affected region of Jianghan Plain, China, based on annual average temperature, humidity of the climate, soil type, normalized difference vegetation index, land use, ditch density, land surface temperature, and digital elevation model variables; each variable’s contribution was tested using the jackknife method. Several key results emerged. First, coverage area of O. hupensis had changed little from 2007 to 2012, with some cities, counties, and districts alternately increasing and decreasing, with ditch and bottomland being the main habitat types. Second, although it showed a weak spatial autocorrelation, changing negligibly, there was a significant east–west gradient in the O. hupensis habitat area. Third, 21.9% of Gong’an County’s area was at high risk of snail presence; and ditch density, temperature, elevation, and wetting index contributed most to their occurrence. Our findings and methods provide valuable and timely insight for the control, monitoring, and management of schistosomiasis in China.
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Affiliation(s)
- Yingnan Niu
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Rendong Li
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
| | - Juan Qiu
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
| | - Xingjian Xu
- Hubei Provincial Center for Disease Control and Prevention, Wuhan 430079, China.
| | - Duan Huang
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qihui Shao
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ying Cui
- Key Laboratory of Monitoring and Estimate for Environment and Disaster of Hubei Province, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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24
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A Call for Systems Epidemiology to Tackle the Complexity of Schistosomiasis, Its Control, and Its Elimination. Trop Med Infect Dis 2019; 4:tropicalmed4010021. [PMID: 30699922 PMCID: PMC6473336 DOI: 10.3390/tropicalmed4010021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 12/20/2022] Open
Abstract
Ever since the first known written report of schistosomiasis in the mid-19th century, researchers have aimed to increase knowledge of the parasites, their hosts, and the mechanisms contributing to infection and disease. This knowledge generation has been paramount for the development of improved intervention strategies. Yet, despite a broad knowledge base of direct risk factors for schistosomiasis, there remains a paucity of information related to more complex, interconnected, and often hidden drivers of transmission that hamper intervention successes and sustainability. Such complex, multidirectional, non-linear, and synergistic interdependencies are best understood by looking at the integrated system as a whole. A research approach able to address this complexity and find previously neglected causal mechanisms for transmission, which include a wide variety of influencing factors, is needed. Systems epidemiology, as a holistic research approach, can integrate knowledge from classical epidemiology, with that of biology, ecology, social sciences, and other disciplines, and link this with informal, tacit knowledge from experts and affected populations. It can help to uncover wider-reaching but difficult-to-identify processes that directly or indirectly influence exposure, infection, transmission, and disease development, as well as how these interrelate and impact one another. Drawing on systems epidemiology to address persisting disease hotspots, failed intervention programmes, and systematically neglected population groups in mass drug administration programmes and research studies, can help overcome barriers in the progress towards schistosomiasis elimination. Generating a comprehensive view of the schistosomiasis system as a whole should thus be a priority research agenda towards the strategic goal of morbidity control and transmission elimination.
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