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Tabo Z, Luboobi L, Kraft P, Breuer L, Albrecht C. Control of schistosomiasis by the selective competitive and predatory intervention of intermediate hosts: A mathematical modeling approach. Math Biosci 2024; 376:109263. [PMID: 39089572 DOI: 10.1016/j.mbs.2024.109263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 06/24/2024] [Accepted: 07/24/2024] [Indexed: 08/04/2024]
Abstract
Schistosomiasis, a freshwater-borne neglected tropical disease, disproportionately affects impoverished communities mainly in the tropical regions. Transmission involves humans and intermediate host (IH) snails. This manuscript introduces a mathematical model to probe schistosomiasis dynamics and the role of non-host snail competitors and predators as biological control agents for IH snails. The numerical analyses include investigations into steady-state conditions and reproduction numbers associated with uncontrolled scenarios, as well as scenarios involving non-host snail competitors and/or predators. Sensitivity analysis reveals that increasing snail mortality rates is a key to reducing the IH snail population and control of the transmission. Results show that specific snail competitors and/or predators with strong competition/predation abilities reduce IH snails and the subsequent infectious cercaria populations, reduce the transmission, and possibly eradicate the disease, while those with weaker abilities allow disease persistence. Hence our findings advocate for the effectiveness of snail competitors with suitable competitive pressures and/or predators with appropriate predatory abilities as nature-based solutions for combating schistosomiasis, all while preserving IH snail biodiversity. However, if these strategies are implemented at insignificant levels, IH snails can dominate, and disease persistence may pose challenges. Thus, experimental screening of potential (native) snail competitors and/or predators is crucial to assess the likely behavior of biological agents and determine the optimal biological control measures for IH snails.
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Affiliation(s)
- Zadoki Tabo
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392, Giessen, Germany; Department of Landscape Ecology and Resource Management, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392, Giessen, Germany.
| | - Livingstone Luboobi
- Independent Researcher, C/O Department of Mathematics, Makerere University, Kampala, Uganda
| | - Philipp Kraft
- Department of Landscape Ecology and Resource Management, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392, Giessen, Germany
| | - Lutz Breuer
- Department of Landscape Ecology and Resource Management, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392, Giessen, Germany; Centre for International Development and Environmental Research (ZEU), Justus Liebig University Giessen, Senckenbergstrasse 3, 35390, Giessen, Germany
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392, Giessen, Germany
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Tabo Z, Kalinda C, Breuer L, Albrecht C. Exploring the interplay between climate change and schistosomiasis transmission dynamics. Infect Dis Model 2024; 9:158-176. [PMID: 38268699 PMCID: PMC10805680 DOI: 10.1016/j.idm.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/07/2023] [Accepted: 12/16/2023] [Indexed: 01/26/2024] Open
Abstract
Schistosomiasis, a neglected tropical disease caused by parasitic worms, poses a major public health challenge in economically disadvantaged regions, especially in Sub-Saharan Africa. Climate factors, such as temperature and rainfall patterns, play a crucial role in the transmission dynamics of the disease. This study presents a deterministic model that aims to evaluate the temporal and seasonal transmission dynamics of schistosomiasis by examining the influence of temperature and rainfall over time. Equilibrium states are examined to ascertain their existence and stability employing the center manifold theory, while the basic reproduction number is calculated using the next-generation technique. To validate the model's applicability, demographic and climatological data from Uganda, Kenya, and Tanzania, which are endemic East African countries situated in the tropical region, are utilized as a case study region. The findings of this study provide evidence that the transmission of schistosomiasis in human populations is significantly influenced by seasonal and monthly variations, with incidence rates varying across countries depending on the frequency of temperature and rainfall. Consequently, the region is marked by both schistosomiasis emergencies and re-emergences. Specifically, it is observed that monthly mean temperatures within the range of 22-27 °C create favorable conditions for the development of schistosomiasis and have a positive impact on the reproduction numbers. On the other hand, monthly maximum temperatures ranging from 27 to 33 °C have an adverse effect on transmission. Furthermore, through sensitivity analysis, it is projected that by the year 2050, factors such as the recruitment rate of snails, the presence of parasite egg-containing stools, and the rate of miracidia shedding per parasite egg will contribute significantly to the occurrence and control of schistosomiasis infections. This study highlights the significant influence of seasonal and monthly variations, driven by temperature and rainfall patterns, on the transmission dynamics of schistosomiasis. These findings underscore the importance of considering climate factors in the control and prevention strategies of schistosomiasis. Additionally, the projected impact of various factors on schistosomiasis infections by 2050 emphasizes the need for proactive measures to mitigate the disease's impact on vulnerable populations. Overall, this research provides valuable insights to anticipate future challenges and devise adaptive measures to address schistosomiasis transmission patterns.
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Affiliation(s)
- Zadoki Tabo
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392 Giessen, Germany
- Department of Landscape Ecology and Resource Management, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392 Giessen, Germany
| | - Chester Kalinda
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392 Giessen, Germany
- Bill and Joyce Cummings Institute of Global Health, University of Global Health Equity | Kigali Heights, Plot 772 KG 7 Ave. PO Box 6955, Kigali, Rwanda
| | - Lutz Breuer
- Department of Landscape Ecology and Resource Management, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392 Giessen, Germany
- Centre for International Development and Environmental Research (ZEU), Justus Liebig University Giessen, Senckenbergstrasse 3, 35390 Giessen, Germany
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Heinrich-Buff-Ring 26 (iFZ), 35392 Giessen, Germany
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Guo C, Zhang P, Li J, Zhou C, Yang Z, Zhang Y, Luo Y, Zhou J, Cai Y, Ming Y. The characteristics of intestinal microbiota in patients with chronic schistosomiasis japonica-induced liver fibrosis by 16S rRNA gene sequence. Front Microbiol 2023; 14:1276404. [PMID: 37854336 PMCID: PMC10579597 DOI: 10.3389/fmicb.2023.1276404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 09/19/2023] [Indexed: 10/20/2023] Open
Abstract
Background The intestinal microbiota is known to play a role in the development of liver disease, there is a limited understanding of the intestinal microbiota associated with chronic schistosomiasis japonica. This study sought to explore the characteristics of the intestinal microbiota in patients with chronic schistosomiasis japonica and identify potential biomarkers that could aid diagnosis. Methods A total of 40 residents of Qingshan Island in Yueyang (Hunan, China) were enrolled in this cross-sectional study. These individuals were divided into two groups for analysis of the intestinal microbiota: patients with chronic schistosomiasis japonica-induced liver fibrosis group (CSJ group, n = 10) and a healthy control group (HC group, n = 30). Feces were collected from each participant and analyzed by 16S rRNA gene sequencing, which included species composition analysis at the phylum and family levels, α and β diversity analysis, LEfSe, Kyoto Encyclopedia of Genes and Genome (KEGG) and Clusters of Orthologous Groups of proteins (COG) analysis. Results Our results indicated that Schistosoma japonicum infection changed the composition and abundance of intestinal microbiota at the phylum and family levels. Compared with the HC group, the α and β diversity results showed that CSJ group had low diversity of species of the intestinal microbiome. LEfSe and relative abundance analysis found that the Prevotella 7, Alloprevotella, and Holdemanella genera were significantly higher in the CSJ group than in the HC group. Meanwhile, the ROC analysis showed that the area under the curve (AUC) of Prevotella 7, Alloprevotella, and Holdemanella genera was 0.779, 0.769, and 0.840, respectively. KEGG and COG analysis showed that the Replication and Repair, and Defense Mechanism pathways correlated strongly with chronic schistosomiasis japonica infection. Conclusion The current study was the first to explore differences in the intestinal microbiota of patients with chronic schistosomiasis japonica-induced liver fibrosis and healthy people from Qingshan Island, which indicated that Prevotella 7, Alloprevotella, and Holdemanella genera could have a potential value in non-invasive diagnosis of chronic schistosomiasis japonica-induced fibrosis.
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Affiliation(s)
- Chen Guo
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Pengpeng Zhang
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Junhui Li
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Chen Zhou
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhen Yang
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yu Zhang
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yulin Luo
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Jie Zhou
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, China
| | - Yu Cai
- Hunan Institute of Schistosomiasis Control, Yueyang, Hunan, China
| | - Yingzi Ming
- Organ Transplantation Center, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
- Engineering and Technology Research Center for Transplantation Medicine of the National Ministry of Health, The Third Xiangya Hospital of Central South University, Changsha, Hunan, China
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Li Y, Guo S, Dang H, Zhang L, Xu J, Li S. Oncomelania hupensis Distribution and Schistosomiasis Transmission Risk in Different Environments under Field Conditions. Trop Med Infect Dis 2023; 8:tropicalmed8050242. [PMID: 37235290 DOI: 10.3390/tropicalmed8050242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/15/2023] [Accepted: 04/16/2023] [Indexed: 05/28/2023] Open
Abstract
The goal of schistosomiasis prevention and control in China is shifting from transmission interruption to elimination. However, the area inhabited by the intermediate host, the snail Oncomelania hupensis, has not changed much in recent years. Different environmental types have different impacts on snail breeding, and understanding these differences is conducive to improving the efficiency of snail monitoring and control and to saving resources. Based on previous epidemiological data, we selected 199 villages in 2020 and 269 villages in 2021 from transmission control, transmission interruption, and elimination areas of snail breeding. Snail surveys were conducted in selected villages using systematic sampling and/or environmental sampling methods in six types of snail-breeding environments (canals, ponds, paddy fields, dry lands, bottomlands, and undefined environments). All live snails collected from the field were evaluated for Schistosoma japonicum infection using the microscopic dissection method, and a subsample of snails was subjected to loop-mediated isothermal amplification (LAMP) to assess the presence of S. japonicum infection. Snail distribution data and infection rate and nucleic acid positive rate of schistosomes in snails were calculated and analyzed. The 2-year survey covered 29,493 ha of the environment, in which 12,313 ha of snail habitats were detected. In total, 51.16 ha of new snail habitats and 107.76 ha of re-emergent snail habitats were identified during the survey. The occurrence rate of snails in canals (10.04%, 95% CI: 9.88-10.20%) and undefined environments (20.66%, 95% CI: 19.64-21.67%) was relatively high in 2020, and the density of snails in bottomlands (0.39, 95% CI: 0.28-0.50) and undefined environments (0.43, 95% CI: 0.14-1.60) was relatively high in 2021. Of the 227,355 live snails collected in this study, none were S. japonicum-positive as determined by microscopy. Of the 20,131 pooled samples, however, 5 were S. japonicum-positive based on LAMP analysis, and they were distributed in three environmental types: 3 in bottomland, 1 in dry land, and 1 in a canal. The bottomland environment has a high risk of schistosomiasis transmission because it contains a large area of newly emerging and re-emerging snail habitats, and it also had the most breeding snails infected with S. japonicum. Thus, this habitat type should be the key target for snail monitoring and early warning and for the prevention and control of schistosomiasis.
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Affiliation(s)
- Yinlong Li
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
| | - Suying Guo
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
| | - Hui Dang
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
| | - Lijuan Zhang
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
| | - Jing Xu
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
| | - Shizhu Li
- National Institute of Parasitic Disease, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Disease Research), NHC Key Laboratory of Parasite and Vector Biology, WHO Collaborating Center for Tropical Disease, National Center for International Research on Tropical Disease, Shanghai 200025, China
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Lv C, Li YL, Deng WP, Bao ZP, Xu J, Lv S, Li SZ, Zhou XN. The Current Distribution of Oncomelania hupensis Snails in the People's Republic of China Based on a Nationwide Survey. Trop Med Infect Dis 2023; 8:tropicalmed8020120. [PMID: 36828536 PMCID: PMC9962009 DOI: 10.3390/tropicalmed8020120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
Schistosomiasis is a helminth infection caused by the genus Schistosoma, which is still a threat in tropical and sub-tropical areas. In the China, schistosomiasis caused by Schistosoma japonicum is mainly endemic to the Yangtze River valley. The amphibious snail Oncomelania hupensis (O. hupensis) is the unique intermediate host of S. japonicum; hence, snail control is a crucial approach in the process of schistosomiasis transmission control and elimination. In 2016, a nationwide snail survey was conducted involving all snail habitats recorded since 1950 in all endemic counties of 12 provinces. A total of 53,254 existing snail habitats (ESHs) were identified, presenting three clusters in Sichuan Basin, Dongting Lake, and Poyang Lake. The overall habitat area was 5.24 billion m2, of which 3.58 billion m2 were inhabited by O. hupensis. The area inhabited by snails (AIS) in Dongting and Poyang Lakes accounted for 76.53% of the population in the country. Three typical landscape types (marshland and lakes, mountains and hills, and plain water networks) existed in endemic areas, and marshland and lakes had a predominant share (3.38 billion m2) of the AIS. Among the 12 endemic provinces, Hunan had a share of nearly 50% of AIS, whereas Guangdong had no ESH. Ditches, dryland, paddy fields, marshland, and ponds are common habitat types of the ESH. Although the AIS of the marshland type accounted for 87.22% of the population in the whole country, ditches were the most common type (35,025 or 65.77%) of habitat. Six categories of vegetation for ESHs were identified. A total of 39,139 habitats were covered with weeds, accounting for 55.26% of the coverage of the area. Multiple vegetation types of snail habitats appeared in the 11 provinces, but one or two of these were mainly dominant. Systematic sampling showed that the presence of living snails was 17.88% among the 13.5 million sampling frames. The occurrence varied significantly by landscape, environment, and vegetation type. The median density of living snails in habitats was 0.50 per frame (0.33 m × 0.33 m), and the highest density was 40.01 per frame. Furthermore, two main clusters with high snail densities and spatial correlations indicated by hotspot analysis were identified: one in Hunan and Hubei, the other in Sichuan. This national survey is the first full-scale census on the distribution of O. hupensis, which is significant, as transmission interruption and elimination are truly becoming the immediate goal of schistosomiasis control in China. The study discerns the detailed geographic distribution of O. hupensis with the hotspots of snail density in China. It is beneficial to understand the status of the snail population in order to finally formulate further national control planning.
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Affiliation(s)
- Chao Lv
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University, The University of Edinburgh, Shanghai 200025, China
| | - Yin-Long Li
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
| | - Wang-Ping Deng
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
| | - Zi-Ping Bao
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
| | - Jing Xu
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
| | - Shan Lv
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University, The University of Edinburgh, Shanghai 200025, China
- Correspondence: (S.L.); (S.-Z.L.); (X.-N.Z.)
| | - Shi-Zhu Li
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University, The University of Edinburgh, Shanghai 200025, China
- Correspondence: (S.L.); (S.-Z.L.); (X.-N.Z.)
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, China CDC (Chinese Center for Tropical Diseases Research), Key Laboratory on Parasite and Vector Biology, National Health Commission, WHO Collaborating Centre for Tropical Diseases, National Center for International Research on Tropical Diseases, Ministry of Science and Technology, Shanghai 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
- One Health Center, Shanghai Jiao Tong University, The University of Edinburgh, Shanghai 200025, China
- Correspondence: (S.L.); (S.-Z.L.); (X.-N.Z.)
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Nemungadi TG, Furumele TE, Gugerty MK, Djirmay AG, Naidoo S, Kjetland EF. Establishing and Integrating a Female Genital Schistosomiasis Control Programme into the Existing Health Care System. Trop Med Infect Dis 2022; 7:tropicalmed7110382. [PMID: 36422933 PMCID: PMC9696272 DOI: 10.3390/tropicalmed7110382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/02/2022] [Accepted: 11/09/2022] [Indexed: 11/19/2022] Open
Abstract
Female genital schistosomiasis (FGS) is a complication of Schistosoma haematobium infection, and imposes a health burden whose magnitude is not fully explored. It is estimated that up to 56 million women in sub-Saharan Africa have FGS, and almost 20 million more cases will occur in the next decade unless infected girls are treated. Schistosomiasis is reported throughout the year in South Africa in areas known to be endemic, but there is no control programme. We analyze five actions for both a better understanding of the burden of FGS and reducing its prevalence in Africa, namely: (1) schistosomiasis prevention by establishing a formal control programme and increasing access to treatment, (2) introducing FGS screening, (3) providing knowledge to health care workers and communities, (4) vector control, and (5) water, sanitation, and hygiene. Schistosomiasis is focal in South Africa, with most localities moderately affected (prevalence between 10% and 50%), and some pockets that are high risk (more than 50% prevalence). However, in order to progress towards elimination, the five actions are yet to be implemented in addition to the current (and only) control strategy of case-by-case treatment. The main challenge that South Africa faces is a lack of access to WHO-accredited donated medication for mass drug administration. The establishment of a formal and funded programme would address these issues and begin the implementation of the recommended actions.
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Affiliation(s)
- Takalani Girly Nemungadi
- Discipline of Public Health Medicine, School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa
- Communicable Disease Control Directorate, National Department of Health, Pretoria 0001, South Africa
- Correspondence:
| | - Tsakani Ernica Furumele
- Communicable Disease Control Directorate, National Department of Health, Pretoria 0001, South Africa
| | - Mary Kay Gugerty
- Evans School of Public Policy & Governance, University of Washington, Seattle, WA 98195-3055, USA
| | - Amadou Garba Djirmay
- Department of the Control of Neglected Tropical Diseases, World Health Organization, 1211 Geneva, Switzerland
| | - Saloshni Naidoo
- Discipline of Public Health Medicine, School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa
| | - Eyrun Flörecke Kjetland
- Discipline of Public Health Medicine, School of Nursing and Public Health, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South Africa
- Norwegian Centre for Imported and Tropical Diseases, Department of Infectious Diseases Ullevaal, Oslo University Hospital, 0424 Oslo, Norway
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Environmental DNA in human and veterinary parasitology - Current applications and future prospects for monitoring and control. Food Waterborne Parasitol 2022; 29:e00183. [DOI: 10.1016/j.fawpar.2022.e00183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 11/04/2022] [Accepted: 11/09/2022] [Indexed: 11/15/2022] Open
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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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Safety Surveillance of Mass Praziquantel and Albendazole Co-Administration in School Children from Southern Ethiopia: An Active Cohort Event Monitoring. J Clin Med 2022; 11:jcm11216300. [PMID: 36362528 PMCID: PMC9656481 DOI: 10.3390/jcm11216300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/23/2022] [Accepted: 10/23/2022] [Indexed: 11/17/2022] Open
Abstract
Preventive chemotherapy (PC) with praziquantel and albendazole co-administration to all at-risk populations is the global intervention strategy to eliminate schistosomiasis and soil-transmitted helminth (STH) from being public health problems. Due to weak pharmacovigilance systems, safety monitoring during a mass drug administration (MDA) is lacking, especially in sub-Saharan Africa. We conducted large-scale active safety surveillance to identify the incidence, types, severity, and associated risk factors of adverse events (AEs) following praziquantel and albendazole MDA in 5848 school children (5−15 years old). Before MDA, 1484 (25.4%) children were prescreened for S. mansoni and STH infections, of whom 71.8% were infected with at least one parasite; 34.5% (512/1484) had S. mansoni and 853 (57.5%) had an STH infection. After collecting the baseline socio-demographic, clinical, and medical data, including any pre-existing clinical symptoms, participants received single dose praziquantel and albendazole MDA. Treatment-associated AEs were actively monitored on days 1 and 7 of the MDA. The events reported before and after the MDA were cross-checked and verified to identify MDA-associated AEs. The cumulative incidence of experiencing at least one type of MDA-associated AE was 13.3% (95% CI = 12.5−14.2%); 85.5%, 12.4%, and 1.8% of reported AEs were mild, moderate, and severe, respectively. The proportion of experiencing one, two, or ≥ three types of AEs was 57.7%, 34.1%, and 8.2%, respectively. The cumulative incidence of AEs in S. mansoni- and (17.0%) and STH (14.1%)-infected children was significantly higher (p < 0.001, χ2 = 15.0) than in non-infected children (8.4%). Headache, abdominal pain, vomiting, dizziness, and nausea were the most common AEs. Being female, older age, having S. mansoni or STH infection were significant predictors of MDA-associated AEs. In summary, praziquantel and albendazole co-administration is generally safe and tolerable. MDA-associated AEs are mostly mild-to-moderately severe and transient. The finding of few severe AEs and significantly high rates of AEs in helminth-infected children underscores the need to integrate pharmacovigilance in MDA programs, especially in high schistosomiasis and STH endemic areas.
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Optimizing Implementation of Preventive Chemotherapy against Soil-Transmitted Helminthiasis and Intestinal Schistosomiasis Using High-Resolution Data: Field-Based Experiences from Côte d’Ivoire. Diseases 2022; 10:diseases10040066. [PMID: 36278565 PMCID: PMC9590038 DOI: 10.3390/diseases10040066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/07/2022] [Accepted: 09/14/2022] [Indexed: 11/17/2022] Open
Abstract
Background: Despite efforts to control neglected tropical diseases (NTDs) using preventive chemotherapy (PC), soil-transmitted helminthiases and schistosomiasis remain widely prevalent in sub-Saharan Africa. The current PC regimen in endemic settings is defined based on health district-level prevalence. This work aims to highlight the need for high-resolution data when elimination, rather than morbidity control, is the targeted goal. Methodology: Cross-sectional parasitological surveys were conducted from July to August 2019 and from September to October 2019, respectively, across the entire Dabou and Jacqueville health districts in southern Côte d’Ivoire. From every village, 60 school-aged children (6–15 years) were randomly selected and invited to provide one fresh stool sample, whereof duplicate Kato–Katz thick smears were prepared and read by two independent technicians. Principal Findings: 4338 school-aged children from 77 villages were screened from the Dabou (n = 2174; 50.12%, 39 villages) and Jacqueville (n = 2164; 49.88%, 38 villages) health districts. The prevalence of any soil-transmitted helminth (STH) infection was 12.47% and 11.09% in the Dabou and Jacqueville health districts, respectively. Species-specific district-level prevalence remained below 10%, varying between 0.51% (hookworm in Jacqueville) and 9.06% (Trichuris trichiura in Dabou). However, when considering sub-districts or villages only, several STH infection hotspots (five sub-districts with ≥20% and four villages with more than 50% infected) were observed. Schistosoma mansoni infection was found in less than 1% of the examined children in each health district. Conclusions/Significance: We conclude that keeping health district-level prevalence as a reference for PC implementation leaves many high-risk sub-districts or villages requiring PC (≥20% prevalence) untreated. To avoid maintaining those high-risk villages as STH reservoirs by skipping control interventions and jeopardizing the successes already achieved in STH control through PC during the past two decades, precision mapping is required. Further investigation is needed to assess cost-efficient approaches to implement small-scale disease surveillance.
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Morales-Vicente DA, Zhao L, Silveira GO, Tahira AC, Amaral MS, Collins JJ, Verjovski-Almeida S. Single-cell RNA-seq analyses show that long non-coding RNAs are conspicuously expressed in Schistosoma mansoni gamete and tegument progenitor cell populations. Front Genet 2022; 13:924877. [PMID: 36204320 PMCID: PMC9531161 DOI: 10.3389/fgene.2022.924877] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
Schistosoma mansoni is a flatworm that causes schistosomiasis, a neglected tropical disease that affects over 200 million people worldwide. New therapeutic targets are needed with only one drug available for treatment and no vaccine. Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with low or no protein-coding potential. In other organisms, they have been shown as involved with reproduction, stem cell maintenance and drug resistance, and they tend to exhibit tissue-specific expression patterns. S. mansoni expresses thousands of lncRNA genes; however, the cell type expression patterns of lncRNAs in the parasite remain uncharacterized. Here, we have re-analyzed publicly available single-cell RNA-sequencing (scRNA-seq) data obtained from adult S. mansoni to identify the lncRNAs signature of adult schistosome cell types. A total of 8023 lncRNAs (79% of all lncRNAs) were detected. Analyses of the lncRNAs expression profiles in the cells using statistically stringent criteria were performed to identify 74 lncRNA gene markers of cell clusters. Male gamete and tegument progenitor lineages clusters contained most of the cluster-specific lncRNA markers. We also identified lncRNA markers of specific neural clusters. Whole-mount in situ hybridization (WISH) and double fluorescence in situ hybridization were used to validate the cluster-specific expression of 13 out of 16 selected lncRNA genes (81%) in the male and female adult parasite tissues; for one of these 16 gene loci, probes for two different lncRNA isoforms were used, which showed differential isoform expression in testis and ovary. An atlas of the expression profiles across the cell clusters of all lncRNAs detected in our analysis is available as a public website resource (http://verjolab.usp.br:8081). The results presented here give strong support to a tissue-specific expression and to a regulated expression program of lncRNAs in S. mansoni. This will be the basis for further exploration of lncRNA genes as potential therapeutic targets.
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Affiliation(s)
- David A. Morales-Vicente
- Laboratório de Parasitologia, Instituto Butantan, São Paulo, Brazil
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Lu Zhao
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Gilbert O. Silveira
- Laboratório de Parasitologia, Instituto Butantan, São Paulo, Brazil
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
| | - Ana C. Tahira
- Laboratório de Parasitologia, Instituto Butantan, São Paulo, Brazil
| | - Murilo S. Amaral
- Laboratório de Parasitologia, Instituto Butantan, São Paulo, Brazil
| | - James J. Collins
- Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, United States
| | - Sergio Verjovski-Almeida
- Laboratório de Parasitologia, Instituto Butantan, São Paulo, Brazil
- Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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Miranda GS, Rodrigues JGM, Silva JKADO, Camelo GMA, Silva-Souza N, Neves RH, Machado-Silva JR, Negrão-Corrêa DA. New challenges for the control of human schistosomiasis: The possible impact of wild rodents in Schistosoma mansoni transmission. Acta Trop 2022; 236:106677. [PMID: 36063905 DOI: 10.1016/j.actatropica.2022.106677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/27/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022]
Abstract
Schistosomiasis is a neglected parasitic disease caused by digenean trematodes from the genus Schistosoma that affects millions of people worldwide. Despite efforts to control its transmission, this disease remains active within several endemic regions of Africa, Asia, and the Americas. In addition to the deficits in sanitation and educational structure, another major obstacle hindering the eradication of schistosomiasis is the ability of Schistosoma spp. to naturally infect multiple vertebrate hosts, particularly wild rodents. Due to climate change and other anthropogenic disturbances, contact between humans and wild animals has increased, and this has contributed to more frequent interactions between Schistosoma species that typically infect different hosts. This new transmission dynamic involving Schistosoma spp., humans, wild rodents, and livestock could potentially increase the frequency of Schistosoma hybridization and the establishment of new genotypes and strains. Although it is not currently possible to precisely measure how this biological phenomenon affects the epidemiology and morbidity of schistosomiasis, we speculate that these Schistosoma variants may negatively impact control strategies, treatment regimens, and disease burden in humans. In the present study, we discuss the natural infections of wild rodents with Schistosoma spp., the role of these animals as Schistosoma spp. reservoirs, and how they may select hybrids and strains of Schistosoma mansoni. We also discuss measures required to shed light on the actual role of the wild rodents Nectomys squamipes and Holochilus sciureus in the transmission and morbidity of schistosomiasis in Brazil.
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Affiliation(s)
- Guilherme Silva Miranda
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Avenida Antônio Carlos 6627, Campus Pampulha, Belo Horizonte, MG CEP: 31270-010, Brazil; Department of Biology, Federal Institute of Education, Science and Technology of Maranhão, São Raimundo das Mangabeiras, Brazil
| | - João Gustavo Mendes Rodrigues
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Avenida Antônio Carlos 6627, Campus Pampulha, Belo Horizonte, MG CEP: 31270-010, Brazil
| | - Jeferson Kelvin Alves de Oliveira Silva
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Avenida Antônio Carlos 6627, Campus Pampulha, Belo Horizonte, MG CEP: 31270-010, Brazil
| | - Genil Mororó Araújo Camelo
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Avenida Antônio Carlos 6627, Campus Pampulha, Belo Horizonte, MG CEP: 31270-010, Brazil
| | - Nêuton Silva-Souza
- Department of Chemistry and Biology, State University of Maranhão, São Luis, Brazil
| | - Renata Heisler Neves
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Biomedical Center, University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - José Roberto Machado-Silva
- Department of Microbiology, Immunology and Parasitology, Faculty of Medical Sciences, Biomedical Center, University of the State of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Deborah Aparecida Negrão-Corrêa
- Department of Parasitology, Institute of Biological Sciences, Federal University of Minas Gerais, Avenida Antônio Carlos 6627, Campus Pampulha, Belo Horizonte, MG CEP: 31270-010, Brazil.
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Identification of a linear B-cell epitope on the Schistosoma japonicum saposin protein, SjSAP4: Potential as a component of a multi-epitope diagnostic assay. PLoS Negl Trop Dis 2022; 16:e0010619. [PMID: 35816547 PMCID: PMC9302751 DOI: 10.1371/journal.pntd.0010619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/21/2022] [Accepted: 06/29/2022] [Indexed: 11/19/2022] Open
Abstract
Background Schistosoma japonicum is one of three major species of blood flukes causing schistosomiasis, a disease, which continues to be a major public health issue in the Philippines. SjSAP4, a member of a multigene family of saposin-like proteins, is a recognized immunodiagnostic biomarker for schistosomiasis japonica. This study aimed to identify linear B-cell epitopes on SjSAP4 and to validate their potential as components of a multi-epitope assay for the serological diagnosis of schistosomiasis japonica. Methodology SjSAP4-derived peptides were expressed as GST-peptide-fused proteins and these were Western blot probed with human serum samples from S. japonicum Kato-Katz (KK)-positive individuals and uninfected controls. A core epitope was further identified by Western blotting through probing a series of truncated peptides with the schistosomiasis patient sera. The diagnostic performance of the core epitope-containing peptides and the full-length SjSAP4 was evaluated by enzyme-linked immunosorbent assay (ELISA) using a panel of sera collected from subjects resident in a schistosomiasis-endemic area of the Philippines. Main findings As a result of the peptide mapping, one peptide (P15) was found to be highly immunogenic in the KK-positive individuals. We subsequently showed that -S163QCSLVGDIFVDKYLD178- is a core B-cell epitope of P15. Subsequent ELISAs incorporating SjSAP4, SjSAP4-Peptide and SjSP-13V2-Peptide showed a sensitivity of 94.0%, 46.0% and 74.0%, respectively, and a specificity of 97.1%, 100% and 100%, respectively. Notably, complementary recognition of the B-cell epitopes (SjSAP4-Peptide and SjSP-13V2-Peptide) was observed in a subset of the KK-positive individuals. A dual epitope-ELISA (SjSAP4-Peptide + SjSP-13V2-Peptide-ELISA) showed a diagnostic sensitivity of 84.0% and a specificity of 100%. Conclusions/Significance In this study, -S163QCSLVGDIFVDKYLD178- was identified as a dominant linear B-cell epitope on SjSAP4. This peptide and the complementary recognition of other B-cell epitopes using sera from different KK-positive individuals can provide the basis of developing a multi-epitope assay for the serological diagnosis of schistosomiasis. The recent road map (2021–2030) released by WHO for controlling or eliminating neglected tropical diseases (NTDs) highlights diagnostics as a major focus. Development and deployment of accurate, affordable and field-friendly diagnostics/surveillance tools will be crucial for the control and elimination of schistosomiasis. Multi-epitope chimeric antigens, constructed based on linear B-cell epitopes identified from highly antigenic antigens, may achieve not only an equivalent or superior diagnostic performance compared to the parent immunogens but also exhibit more optimal physicochemical properties. However, to date, only a limited number of linear B-cell epitopes have been identified for the serological diagnosis of schistosomiasis. In this study, we identified a linear B-cell epitope (-S163QCSLVGDIFVDKYLD178-) on SjSAP4, a recognized immunodiagnostic biomarker for schistosomiasis japonica, and validated its potential as a component of a multi-epitope assay for the serological diagnosis of schistosomiasis japonica. Notably, differential recognition of B-cell epitopes (SjSAP4-Peptide and SjSP-13V2-Peptide) was observed in a subset of subjects positive by the Kato-Katz technique for the disease. A dual epitope-ELISA (SjSAP4-Peptide + SjSP-13V2-Peptide-ELISA) showed a superior diagnostic performance (84.0% sensitivity and 100% specificity) than individual-epitope ELISAs. The findings in this study provide support for the development of multi-epitope antigen-based diagnostics for schistosomiasis.
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Zhu H, Liu JB, Xiao Y, Tu ZW, Shan XW, Li B, Wu JL, Zhou XR, Sun LC, Xia J, Liu S, Huang XB. Efforts to eliminate schistosomiasis in Hubei province, China: 2005-2018. Acta Trop 2022; 231:106417. [PMID: 35318000 DOI: 10.1016/j.actatropica.2022.106417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 03/17/2022] [Accepted: 03/17/2022] [Indexed: 11/01/2022]
Abstract
BACKGROUND The Hubei province is one of the most schistosomiasis-epidemic-prone provinces in China. A series of strategies were adopted by the government to curb the rebound schistosomiasis endemic status that has prevailed since the early 2000s. This study aimed to elucidate the trends of schistosomiasis transmission and to appraise the effectiveness of the integrated control strategy in lake and marshland areas. METHODS Surveillance data of schistosomiasis in the Hubei province between 2005 and 2018 were analyzed, including conventional health control measures, integrated strategies, and measures that focused on the infection source. According to the local annual plan for schistosomiasis control in endemic counties, previous measures were human and snail control and surveillance. Residents aged 6-65 years were screened by an immunological detection method called indirect hemagglutination assay (IHA) after the transmission season each year. All residents who tested positive were then asked to provide a fecal sample for examination by the miracidium hatching technique (MHT) to detect the presence of schistosomes. Moreover, systematic snail surveys were conducted as a part of the combined environmental sampling method. The latter included integrated strategies and measures that focused on the infection source. Bovine stool samples were also collected and concurrently assessed using the MHT by the agriculture department, river-hardening slope protection was constructed by the water conservancy department, and forestation promotion was conducted by the forest department. The effectiveness of the integrated control strategy was assessed using two indicators of resident and livestock infection rates and three indicators of snail epidemics across all endemic areas. RESULTS From 2005 to 2018, a total of 28. 46 million and 2. 05 million residents were assessed by immunological (IHA) and etiological (MHT) detection techniques, respectively. Snail surveys and molluscicide application were performed in 2. 26 hectares and 0. 37 hectares, respectively. Moreover, 2. 60 million bovines were assessed by etiological detection techniques (MHT). The river-hardening slope protection project was implemented in 503 places, and 46 thousand hectares in endemic areas underwent environmental modification. Forestation was implemented at an area of 0. 15 million hectares. Between 2005 and 2018, the epidemic indicators, including resident and livestock infection rates and the infested areas and infection rate of snails, all presented downward trends. The resident infection rate decreased from 3. 78% in 2005 to 0% in 2016, which persisted through 2018. The livestock infection rate decreased from 5. 63% in 2005 to 0% in 2013, which also persisted through 2018. From 2005 to 2018, the snail-inhabited area was slightly reduced, but the area of infected snails decreased to 0 in 2012; this persisted through 2018. All counties met the goal for schistosomiasis infection control, transmission control, and disruption of schistosomiasis activity in 2008, 2013, and 2018 separately. That means the goal has been achieved in each stage. CONCLUSIONS The decline of the schistosomiasis epidemic rate demonstrates that the Chinese government was successful in meeting its public health goal in Hubei province. In the next decade, precision interventions must be implemented in endemic counties with a relatively low epidemic status to achieve the goals of the Outline of the Healthy China 2030 Plan. A similar strategy can be applied in other countries to eliminate schistosomiasis globally.
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15
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Li YL, Dang H, Guo SY, Zhang LJ, Feng Y, Ding SJ, Shan XW, Li GP, Yuan M, Xu J, Li SZ. Molecular evidence on the presence of Schistosoma japonicum infection in snails along the Yangtze River, 2015-2019. Infect Dis Poverty 2022; 11:70. [PMID: 35717331 PMCID: PMC9206329 DOI: 10.1186/s40249-022-00995-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/05/2022] [Indexed: 12/12/2022] Open
Abstract
Background Due to sustained control activities, the prevalence of Schistosoma japonicum infection in humans, livestock and snails has decreased significantly in P. R. China, and the target has shifted from control to elimination according to the Outline of Healthy China 2030 Plan. Applying highly sensitive methods to explore the presence of S. japonicum infection in its intermediate host will benefit to assess the endemicity or verify the transmission interruption of schistosomiasis accurately. The aim of this study was to access the presence of S. japonicum infection by a loop-mediated isothermal amplification (LAMP) method through a 5-year longitudinal study in five lake provinces along the Yangtze River. Methods Based on previous epidemiological data, about 260 villages with potential transmission risk of schistosomiasis were selected from endemic counties in five lake provinces along the Yangtze River annually from 2015 to 2019. Snail surveys were conducted in selected villages by systematic sampling method and/or environmental sampling method each year. All live snails collected from field were detected by microscopic dissection method, and then about one third of them were detected by LAMP method to assess the presence of S. japonicum infection with a single blind manner. The infection rate and nucleic acid positive rate of schistosomes in snails, as well as the indicators reflecting the snails’ distribution were calculated and analyzed. Fisher's exact test was used to examine any change of positive rate of schistosomes in snails over time. Results The 5-year survey covered 94,241 ha of environment with 33,897 ha of snail habitats detected accumulatively. Totally 145.3 ha new snail habitats and 524.4 ha re-emergent snail habitats were found during 2015–2019. The percentage of frames with snails decreased from 5.93% [45,152/761,492, 95% confidence intervals (CI): 5.88–5.98%] in 2015 to 5.25% (30,947/589,583, 95% CI: 5.19–5.31%) in 2019, while the mean density of living snails fluctuated but presented a downward trend generally from 0.20 snails/frame (155,622/761,492, 95% CI: 0.17–0.37) in 2015 to 0.13 snails/frame (76,144/589,583, 95% CI: 0.11–0.39) in 2019. A total of 555,393 live snails were collected, none of them was positive by dissection method. Totally 17 pooling snail samples were determined as positives by LAMP method among 8716 pooling samples with 174,822 of living snails, distributed in 12 villages of Hubei, Hunan, Jiangxi and Anhui provinces. The annual average positive rate was 0.41% (95% CI: 0.13–0.69%) in 2015, 0% in 2016, 0.36% (95% CI: 0.09–0.63%) in 2017, 0.05% (95% CI: 0–0.16%) in 2018, 0.05% (95% CI: 0–0.15%) in 2019, respectively, presenting a downward trend from 2015 to 2019 with statistical significance (χ2 = 11.64, P < 0.05). Conclusions The results suggest that S. japonicum infection still persisted in nature along the Yangtze River and traditional techniques might underestimate the prevalence of schistosomiasis in its intermediate hosts. Exploring and integrating molecular techniques into national surveillance programme could improve the sensitivity of surveillance system and provide guidance on taking actions against schistosomiasis. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-022-00995-9.
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Affiliation(s)
- Yin-Long Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China.,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China
| | - Hui Dang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China.,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China
| | - Su-Ying Guo
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China.,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China
| | - Li-Juan Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China.,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China
| | - Yun Feng
- Jiangsu Provincial Institute of Schistosomiasis Control, Wuxi, Jiangsu Province, 214064, People's Republic of China
| | - Song-Jun Ding
- Anhui Provincial Institute of Schistosomiasis Control, Hefei, Anhui Province, 230061, People's Republic of China
| | - Xiao-Wei Shan
- Hubei Provincial Institute of Schistosomiasis Control, Hubei Center for Disease Control, Wuhan, Hubei Province, 430079, People's Republic of China
| | - Guang-Ping Li
- Hunan Provincial Institute of Schistosomiasis Control, Hunan Province 414000, Yueyang, People's Republic of China
| | - Min Yuan
- Jiangxi Provincial Institute of Parasitic Disease, Nanchang, Jiangxi Province, 330006, People's Republic of China
| | - Jing Xu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China. .,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China. .,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China. .,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China.
| | - Shi-Zhu Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai, 200025, People's Republic of China.,NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, People's Republic of China.,WHO Collaborating Centre for Tropical Diseases, Shanghai, 200025, People's Republic of China.,National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China
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Deng W, Wang S, Wang L, Lv C, Li Y, Feng T, Qin Z, Xu J. Laboratory Evaluation of a Basic Recombinase Polymerase Amplification (RPA) Assay for Early Detection of Schistosoma japonicum. Pathogens 2022; 11:pathogens11030319. [PMID: 35335643 PMCID: PMC8955429 DOI: 10.3390/pathogens11030319] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/25/2022] [Accepted: 03/03/2022] [Indexed: 02/01/2023] Open
Abstract
Early detection of Schistosoma japonicum (S. japonicum) within its intermediate and definitive hosts is crucial for case finding and disease surveillance, especially in low-endemic areas. Recombinase polymerase amplification (RPA) has many advantages over traditional methods of DNA-amplification, such as polymerase chain reaction (PCR), including high sensitivity and specificity whilst being deployable in resource-poor schistosomiasis-endemic areas. Here, we evaluated the performance of a basic RPA assay targeting the 28srDNA gene fragment of S. japonicum (Sj28srDNA) using schistosome-infected Oncomelania hupensis (O. hupensis) and mouse models, compared to the traditional pathological method and a PCR assay. Overall S. japonicum infection prevalence within O. hupensis hosts by microscopic dissection, PCR and RPA was 9.29% (13/140), 32.14% (45/140) and 51.43% (72/140), respectively, presenting significant differences statistically (χ2 = 58.31, p < 0.001). It was noteworthy that infection prevalence by PCR and RPA performed was 34.44% (31/90) and 53.33% (48/90) in snails within 6 weeks post-infection, while the dissection method detected all samples as negatives. In addition, the basic RPA assay presented positive results from the fourth week post-infection and third day post-infection when detecting fecal DNA and serum DNA, respectively, which were extracted from a pooled sample from mice infected with 20 S. japonicum cercariae. This study suggests that the RPA assay has high potential for early detection of S. japonicum infection within its intermediate and definitive hosts.
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Cantara A, Luo Y, Dobrovolná M, Bohalova N, Fojta M, Verga D, Guittat L, Cucchiarini A, Savrimoutou S, Häberli C, Guillon J, Keiser J, Brázda V, Mergny JL. G-quadruplexes in helminth parasites. Nucleic Acids Res 2022; 50:2719-2735. [PMID: 35234933 PMCID: PMC8934627 DOI: 10.1093/nar/gkac129] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 02/07/2022] [Accepted: 02/25/2022] [Indexed: 12/12/2022] Open
Abstract
Parasitic helminths infecting humans are highly prevalent infecting ∼2 billion people worldwide, causing inflammatory responses, malnutrition and anemia that are the primary cause of morbidity. In addition, helminth infections of cattle have a significant economic impact on livestock production, milk yield and fertility. The etiological agents of helminth infections are mainly Nematodes (roundworms) and Platyhelminths (flatworms). G-quadruplexes (G4) are unusual nucleic acid structures formed by G-rich sequences that can be recognized by specific G4 ligands. Here we used the G4Hunter Web Tool to identify and compare potential G4 sequences (PQS) in the nuclear and mitochondrial genomes of various helminths to identify G4 ligand targets. PQS are nonrandomly distributed in these genomes and often located in the proximity of genes. Unexpectedly, a Nematode, Ascaris lumbricoides, was found to be highly enriched in stable PQS. This species can tolerate high-stability G4 structures, which are not counter selected at all, in stark contrast to most other species. We experimentally confirmed G4 formation for sequences found in four different parasitic helminths. Small molecules able to selectively recognize G4 were found to bind to Schistosoma mansoni G4 motifs. Two of these ligands demonstrated potent activity both against larval and adult stages of this parasite.
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Affiliation(s)
- Alessio Cantara
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Yu Luo
- CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405 Orsay, France.,Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Michaela Dobrovolná
- Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic
| | - Natalia Bohalova
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Miroslav Fojta
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Daniela Verga
- CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405 Orsay, France.,CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France
| | - Lionel Guittat
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France.,Université Sorbonne Paris Nord, UFR SMBH, Bobigny, France
| | - Anne Cucchiarini
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Solène Savrimoutou
- ARNA Laboratory, Université de Bordeaux, INSERM U1212, CNRS UMR 5320, UFR des Sciences Pharmaceutiques, Bordeaux, France
| | - Cécile Häberli
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jean Guillon
- ARNA Laboratory, Université de Bordeaux, INSERM U1212, CNRS UMR 5320, UFR des Sciences Pharmaceutiques, Bordeaux, France
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Václav Brázda
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic
| | - Jean Louis Mergny
- Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
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18
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Molecular Techniques as Alternatives of Diagnostic Tools in China as Schistosomiasis Moving towards Elimination. Pathogens 2022; 11:pathogens11030287. [PMID: 35335611 PMCID: PMC8951378 DOI: 10.3390/pathogens11030287] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/13/2022] [Accepted: 02/21/2022] [Indexed: 12/15/2022] Open
Abstract
Schistosomiasis japonica caused by the trematode flukes of Schistosoma japonicum was one of the most grievous infectious diseases in China in the mid-20th century, while its elimination has been placed on the agenda of the national strategic plan of healthy China 2030 after 70 years of continuous control campaigns. Diagnostic tools play a pivotal role in warfare against schistosomiasis but must adapt to the endemic status and objectives of activities. With the decrease of prevalence and infection intensity of schistosomiasis in human beings and livestock, optimal methodologies with high sensitivity and absolute specificity are needed for the detection of asymptomatic cases or light infections, as well as disease surveillance to verify elimination. In comparison with the parasitological methods with relatively low sensitivity and serological techniques lacking specificity, which both had been widely used in previous control stages, the molecular detection methods based on the amplification of promising genes of the schistosome genome may pick up the baton to assist the eventual aim of elimination. In this article, we reviewed the developed molecular methods for detecting S. japonicum infection and their application in schistosomiasis japonica diagnosis. Concurrently, we also analyzed the chances and challenges of molecular tools to the field application process in China.
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19
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Nigo MM, Odermatt P, Salieb–Beugelaar GB, Morozov O, Battegay M, Hunziker PR. Epidemiology of Schistosoma mansoni infection in Ituri Province, north-eastern Democratic Republic of the Congo. PLoS Negl Trop Dis 2021; 15:e0009486. [PMID: 34855748 PMCID: PMC8638996 DOI: 10.1371/journal.pntd.0009486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 05/14/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Schistosomiasis, caused by Schistosoma mansoni, is of great significance to public health in sub-Saharan Africa. In the Democratic Republic of Congo (DRC), information on the burden of S. mansoni infection is scarce, which hinders the implementation of adequate control measures. We assessed the geographical distribution of S. mansoni infection across Ituri province in north-eastern DRC and determined the prevailing risk factors. METHODS/PRINCIPAL FINDINGS Two province-wide, community-based studies were conducted. In 2016, a geographical distribution study was carried out in 46 randomly selected villages across Ituri. In 2017, an in-depth study was conducted in 12 purposively-selected villages, across the province. Households were randomly selected, and members were enrolled. In 2016, one stool sample was collected per participant, while in 2017, several samples were collected per participant. S. mansoni eggs were detected using the Kato-Katz technique. In 2017, a point-of-care circulating cathodic S. mansoni antigen (POC-CCA) urine test was the second used diagnostic approach. Household and individual questionnaires were used to collect data on demographic, socioeconomic, environmental, behavioural and knowledge risk factors. Of the 2,131 participants in 2016, 40.0% were positive of S. mansoni infection. Infection prevalence in the villages ranged from 0 to 90.2%. Of the 707 participants in 2017, 73.1% were tested positive for S. mansoni. Prevalence ranged from 52.8 to 95.0% across the health districts visited. Infection prevalence increased from north to south and from west to east. Exposure to the waters of Lake Albert and the villages' altitude above sea level were associated with the distribution. Infection prevalence and intensity peaked in the age groups between 10 and 29 years. Preschool children were highly infected (62.3%). Key risk factors were poor housing structure (odds ratio [OR] 2.1, 95% 95% confidence interval [CI] 1.02-4.35), close proximity to water bodies (OR 1.72, 95% CI 1.1-2.49), long-term residence in a community (OR 1.41, 95% CI 1.11-1.79), lack of latrine in the household (OR 2.00, 95% CI 1.11-3.60), and swimming (OR 2.53, 95% CI 1.20-5.32) and washing (OR 1.75, 95% CI 1.10-2.78) in local water bodies. CONCLUSIONS/SIGNIFICANCE Our results show that S. mansoni is highly endemic and a major health concern in Ituri province, DRC. Infection prevalence and intensity, and the prevailing socioeconomic, environmental, and behavioural risk factors in Ituri reflect intense exposure and alarming transmission rates. A robust plan of action is urgently needed in the province.
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Affiliation(s)
- Maurice M. Nigo
- Nanomedicine Translation Group, Intensive Care Unit, University Hospital Basel, University of Basel, Basel, Switzerland
- CLINAM–European Foundation for Clinical Nanomedicine, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Institut Supérieur des Techniques Médicales (ISTM) Nyankunde, Bunia, Democratic Republic of Congo
| | - Peter Odermatt
- University of Basel, Basel, Switzerland
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Georgette B. Salieb–Beugelaar
- Nanomedicine Translation Group, Intensive Care Unit, University Hospital Basel, University of Basel, Basel, Switzerland
- CLINAM–European Foundation for Clinical Nanomedicine, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Oleksii Morozov
- Nanomedicine Translation Group, Intensive Care Unit, University Hospital Basel, University of Basel, Basel, Switzerland
- CLINAM–European Foundation for Clinical Nanomedicine, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Manuel Battegay
- University of Basel, Basel, Switzerland
- Department of Infectiology & Hospital Hygiene, University Hospital Basel, Basel, Switzerland
| | - Patrick R. Hunziker
- Nanomedicine Translation Group, Intensive Care Unit, University Hospital Basel, University of Basel, Basel, Switzerland
- CLINAM–European Foundation for Clinical Nanomedicine, Basel, Switzerland
- University of Basel, Basel, Switzerland
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20
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Biendl S, Häberli C, Keiser J. Discovery of novel antischistosomal scaffolds from the open access Pandemic Response Box. Expert Rev Anti Infect Ther 2021; 20:621-629. [PMID: 34612126 DOI: 10.1080/14787210.2022.1990042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Treatment and control of schistosomiasis rely on a single drug, praziquantel. New orally active antischistosomals featuring novel molecular scaffolds are urgently needed to prevent the emergence of resistance. METHODS We screened 400 drug-like compounds contained in the open-access Pandemic Response Box (PRB) against newly transformed schistosomula (NTS) at a concentration of 10 µM scoring death, changes in motility, and morphological alterations. Compounds displaying an activity ≥66% at 72 h underwent testing against adult Schistosoma mansoni in vitro. Fast-acting (≥66% at 24 h), nontoxic drugs focusing on late-stage and approved drugs were investigated in the patent S. mansoni mouse model. RESULTS We identified 26 hits active against NTS, of which 17 elicited ≥66% activity against adult S. mansoni following 24 h of drug exposure. The highest activity against adult S. mansoni was observed with MMV1581558 (EC50 value of 0.18 ± 0.01 µM) and nitazoxanide (0.47 ± 0.07 µM). Of the five compounds tested in vivo, MMV1581558 and the approved drug ozanimod reduced average worm burden versus controls by 42 % and 36 %, respectively, after a single oral dose of 200 mg/kg bodyweight in mice harboring a chronic S. mansoni infection. CONCLUSION MMV1581558 discovered from screening the PRB represents a novel antischistosomal scaffold with high in vitro antischistosomal activity amenable to chemical modification for drug development.
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Affiliation(s)
- Stefan Biendl
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Cécile Häberli
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
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21
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De Boni L, Msimang V, De Voux A, Frean J. Trends in the prevalence of microscopically-confirmed schistosomiasis in the South African public health sector, 2011-2018. PLoS Negl Trop Dis 2021; 15:e0009669. [PMID: 34529659 PMCID: PMC8445405 DOI: 10.1371/journal.pntd.0009669] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/20/2021] [Indexed: 11/25/2022] Open
Abstract
Background Schistosomiasis, also known as bilharzia, is a chronic parasitic blood fluke infection acquired through contact with contaminated surface water. The illness may be mild or can cause significant morbidity with potentially serious complications. Children and those living in rural areas with limited access to piped water and services for healthcare are the most commonly infected. To address the prevalence of the disease in parts of South Africa (SA) effective national control measures are planned, but have not yet been implemented. This study aimed to estimate the prevalence and trends of public sector laboratory-confirmed schistosomiasis cases in SA over an eight-year (2011–2018) period, to inform future control measures. Methodology & principal findings This is a descriptive analysis of secondary data from the National Health Laboratory Service (NHLS). The study included all records of patients for whom microscopic examination detected Schistosoma species eggs in urine or stool specimens from January 2011 to December 2018. Crude estimates of the prevalence were calculated using national census mid-year provincial population estimates as denominators, and simple linear regression was used to analyse prevalence trends. A test rate ratio was developed to describe variations in testing volumes among different groups and to adjust prevalence estimates for testing variations. A total number of 135 627 schistosomiasis cases was analysed with the highest prevalence observed among males and individuals aged 5–19 years. We describe ongoing endemicity in the Eastern Cape Province, and indicate important differences in the testing between population groups. Conclusion While there was no overall change in the prevalence of schistosomiasis during the analysis period, an average of 36 people per 100 000 was infected annually. As such, this represents an opportunity to control the disease and improve quality of life of affected people. Laboratory-based surveillance is a useful method for reporting occurrence and evaluating future intervention programs where resources to implement active surveillance are limited. This is the first paper to describe the prevalence of human schistosomiasis in South Africa using nationally representative data. The prevalence remained consistent during the eight-year period, independent of increasing annual testing volumes. Groups with the highest burden included males and individuals aged 5–19 years. The schistosomiasis-endemic provinces of Limpopo, Mpumalanga and KwaZulu-Natal emerged as the highest-burdened areas, and ongoing endemicity in Eastern Cape Province was demonstrated. Western Cape Province likely reported cases imported from endemic provinces rather than being acquired by local transmission. In summary, schistosomiasis remains an important public health problem in South Africa that needs long-term sustainable, effective standardised interventions to reduce the burden. Passive laboratory-based surveillance is a practical tool for reporting prevalence, and could be used to monitor and evaluate future intervention programs.
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Affiliation(s)
- Liesl De Boni
- South African Field Epidemiology Training Programme, Johannesburg, South Africa
- University of the Witwatersrand, Johannesburg, South Africa
- * E-mail:
| | - Veerle Msimang
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
| | - Alex De Voux
- South African Field Epidemiology Training Programme, Johannesburg, South Africa
| | - John Frean
- University of the Witwatersrand, Johannesburg, South Africa
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Johannesburg, South Africa
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22
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Schistosomiasis Model Incorporating Snail Predator as Biological Control Agent. MATHEMATICS 2021. [DOI: 10.3390/math9161858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Schistosomiasis is a parasitic disease caused by the schistosoma worm. A snail can act as the intermediate host for the parasite. Snail-population control is considered to be an effective way to control schistosomiasis spread. In this paper, we discuss the schistosomiasis model incorporating a snail predator as a biological control agent. We prove that the solutions of the model are non-negative and bounded. The existence condition of equilibrium points is investigated. We determine the basic reproduction number when the predator goes to extinction and when the predator survives. The local stability condition of disease-free equilibrium point is proved using linearization, and the Lienard–Chipart and Routh–Hurwitz criteria. We use center-manifold theory to prove the local stability condition of the endemic equilibrium points. Furthermore, we constructed a Lyapunov function to investigate the global stability condition of the disease-free equilibrium points. To support the analytical results, we presented some numerical simulation results. Our findings suggest that a snail predator as a biological control agent can reduce schistosomiasis prevalence. Moreover, the snail-predator birth rate plays an essential role in controlling schistosomiasis spread.
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23
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Longoni SS, Piubelli C, Perandin F, Rizzi E, Luchetta N, Degani M, Tais S, Mori A, Bisoffi Z. Preliminary evaluation of a new Schistosoma Immunochromatographic Test. Acta Trop 2021; 219:105893. [PMID: 33872586 DOI: 10.1016/j.actatropica.2021.105893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 03/04/2021] [Accepted: 03/15/2021] [Indexed: 11/27/2022]
Abstract
Over 90% of schistosomiasis infections occur in sub-Saharan Africa. A rapid ICT test would be a cheap and easy tool that could be used also in the field. We preliminarily evaluated the performance of a new Schistosoma black-latex based IgG-IgM ICT (Black-ICT) on serum samples. The results indicate a high sensitivity (98.0%) but the specificity depends on the application of a cut-off value that can discriminate between positive and negative samples. Considering a possible direct application of this test on blood from finger prick, the results are promising, providied that a signal intensity scale is developed, guiding the result interpretation.
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24
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Sheehy C, Lawson H, Andriamasy EH, Russell HJ, Reid A, Raderalazasoa GU, Dodge G, Kornitschky R, Penney JMS, Ranaivoson TN, Andrianiaina A, Emmanoela JS, Bustinduy AL, Stothard JR, Andrianjaka L, Spencer SA. Prevalence of intestinal schistosomiasis in pre-school aged children: a pilot survey in Marolambo District, Madagascar. Infect Dis Poverty 2021; 10:87. [PMID: 34172089 PMCID: PMC8235251 DOI: 10.1186/s40249-021-00871-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/07/2021] [Indexed: 12/28/2022] Open
Abstract
School-aged children (SAC) have a considerable burden of intestinal schistosomiasis in Madagascar yet its burden in pre-school aged children (PSAC) is currently overlooked. To assess the at-risk status of PSAC, we undertook a pilot epidemiological survey in June 2019 examining children (n = 89), aged 2–4-years of balanced gender, in six remote villages in Marolambo District, Madagascar. Diagnosis included use of urine-circulating cathodic antigen (CCA) dipsticks and coproscopy of stool with duplicate Kato-Katz (K-K) thick smears. Prevalence of intestinal schistosomiasis by urine-CCA was 67.4% (95% confidence interval [CI]: 56.5–77.2%) and 35.0% (95% CI: 24.7–46.5%) by K-K. The relationship between faecal eggs per gram (epg) and urine-CCA G-scores (G1 to G10) was assessed by linear regression modelling, finding for every increment in G-score, epg increased by 20.4 (6.50–34.4, P = 0.006). Observed proportions of faecal epg intensities were light (78.6%), moderate (17.9%) and heavy (3.6%). Soil-transmitted helminthiasis was noted, prevalence of ascariasis was 18.8% and trichuriasis was 33.8% (hookworm was not reported). Co-infection of intestinal schistosomiasis and soil-transmitted helminthiasis occurred in 36.3% of PSAC. These results provide solid evidence highlighting the overlooked burden of intestinal schistosomiasis in PSAC, and they also offer technical guidance for better surveillance data for the Madagascan national control programme. ![]()
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Affiliation(s)
- Caitlin Sheehy
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK.
| | | | | | - Hannah J Russell
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | - Alice Reid
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - Graham Dodge
- Department of Imaging, Brighton and Sussex University Hospital NHS Trust, Brighton, BN2 5BA, UK
| | - Robbie Kornitschky
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | - James M StJ Penney
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK
| | | | - Antsa Andrianiaina
- Faculté de Médecine, Université D'Antananarivo, Antananarivo, Madagascar
| | - Jenny S Emmanoela
- Faculté de Médecine, Université D'Antananarivo, Antananarivo, Madagascar
| | - Amaya L Bustinduy
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | | | - Stephen A Spencer
- The University of Manchester Medical School, University of Manchester, Manchester, M13 9NT, UK.,Postgraduate Medical Centre, Royal United Hospitals Bath NHS Foundation Trust, Bath, BA1 3NG, UK
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Aula OP, McManus DP, Jones MK, Gordon CA. Schistosomiasis with a Focus on Africa. Trop Med Infect Dis 2021; 6:109. [PMID: 34206495 PMCID: PMC8293433 DOI: 10.3390/tropicalmed6030109] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 12/19/2022] Open
Abstract
Schistosomiasis is a common neglected tropical disease of impoverished people and livestock in many developing countries in tropical Africa, the Middle East, Asia, and Latin America. Substantial progress has been made in controlling schistosomiasis in some African countries, but the disease still prevails in most parts of sub-Saharan Africa with an estimated 800 million people at risk of infection. Current control strategies rely primarily on treatment with praziquantel, as no vaccine is available; however, treatment alone does not prevent reinfection. There has been emphasis on the use of integrated approaches in the control and elimination of the disease in recent years with the development of health infrastructure and health education. However, there is a need to evaluate the present status of African schistosomiasis, primarily caused by Schistosoma mansoni and S. haematobium, and the factors affecting the disease as the basis for developing more effective control and elimination strategies in the future. This review provides an historical perspective of schistosomiasis in Africa and discusses the current status of control efforts in those countries where the disease is endemic.
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Affiliation(s)
- Oyime Poise Aula
- School of Public Health, Faculty of Medicine, University of Queensland, Brisbane 4006, Australia;
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane 4006, Australia
| | - Donald P. McManus
- School of Public Health, Faculty of Medicine, University of Queensland, Brisbane 4006, Australia;
| | - Malcolm K. Jones
- School of Veterinary Sciences, University of Queensland, Gatton 4343, Australia;
| | - Catherine A. Gordon
- School of Public Health, Faculty of Medicine, University of Queensland, Brisbane 4006, Australia;
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26
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Xiong YH, Xu XN, Zheng B. Patented technologies for schistosomiasis control and prevention filed by Chinese applicants. Infect Dis Poverty 2021; 10:84. [PMID: 34118989 PMCID: PMC8199835 DOI: 10.1186/s40249-021-00869-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/25/2021] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Many valuable and productive patented technologies have been developed to control schistosomiasis in China in the past 70 years. We conducted a research to analyse patented technologies for schistosomiasis control and prevention filed by Chinese applicants for determining the future patent layout. METHODS The patent databases of China National Intellectual Property Administration and Baiten were comprehensively searched, and patented technologies for schistosomiasis control and prevention, published between January 1950 and December 2020 filed by Chinese applicants were sorted on 30 December 2020. The patent types, technical fields, and patent development trends were analysed using patent indexing. RESULTS There are 184 valid schistosomiasis control technology patents, among them 128 invention patents. The patents related to schistosomiasis control and prevention technology have gone through the germination, growth, and maturity stages. These phases correspond with three phases in schistosomiasis control in China. The main technical aspects were fundamental research (n = 37), detection (n = 13), chemotherapy (n = 61), and armamentarium/devices (n = 73), of which the number of patents for detection for diagnosis was smaller. The top three specialised technical fields for patents subgroups, focusing on antiparasitic agents, DNA or RNA, vectors and medicines, of which schistosomicides are the major dominant subgroup. CONCLUSIONS We recommend that technologies to be patented for schistosomiasis control and prevention be focused on detection, preliminary studies for molecular detection methods should be significantly enhanced, and patent layout must be performed, which will, in turn, promote accuracy of early diagnosis, not only in humans but also in livestock. It is necessary to develop more anti-schistosomal drugs safely and effectively, exceptionally eco-friendly molluscicides and herbal extracts anti-schistosomes, improve treatment, develop vaccines for use in humans.
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Affiliation(s)
- Yan-Hong Xiong
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, National Health Commission, WHO Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Ministry of Science and Technology, Shanghai, 200025, China
| | - Xue-Nian Xu
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, National Health Commission, WHO Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Ministry of Science and Technology, Shanghai, 200025, China
| | - Bin Zheng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Chinese Center for Tropical Diseases Research, Key Laboratory of Parasite and Vector Biology, National Health Commission, WHO Centre for Tropical Diseases, National Center for International Research On Tropical Diseases, Ministry of Science and Technology, Shanghai, 200025, China.
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27
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Assis TMD, Rabello A, Cota G. Economic evaluations addressing diagnosis and treatment strategies for neglected tropical diseases: an overview. Rev Inst Med Trop Sao Paulo 2021; 63:e41. [PMID: 34037157 PMCID: PMC8149103 DOI: 10.1590/s1678-9946202163041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 04/23/2021] [Indexed: 11/22/2022] Open
Abstract
Neglected tropical diseases (NTDs) are those affecting vulnerable people and
causing additional social and economic burden. The aim of this study was to
carry out a general overview of the health economic assessments involving the
diagnosis and treatment of six NTDs: cutaneous leishmaniasis (CL), Chagas
disease, cysticercosis, filariasis, schistosomiasis and visceral leishmaniasis
(VL). The literature search was based on two of the main medical literature
databases (Medline and SciELO) and identified 46 studies. Twenty-six studies
(57%) addressed therapeutic strategies, while other 20 (43%) assessed diagnostic
or both diagnostic and therapeutic approaches. The studies were published
between 1994 and 2021, and 57% of them (26/46) were carried out in four
countries. Cost-effectiveness analyses were conducted in 59% (27/46) of the
studies. Economic studies of NTDs have timidly increased in recent years.
Despite the improvement of analytical methods, completeness and accuracy of
information, there are few new technologies applied to NTDs and public health
systems. In addition, economic studies for NTDs are concentrated in a few
countries. Thus, this review points out the need for investment in research,
development and training of human resources dedicated to the economic analysis
in health, especially on NTDs, as a strategy to reduce inequalities by
optimizing the use of health resources.
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Affiliation(s)
- Tália Machado de Assis
- Fundação Oswaldo Cruz, Instituto René Rachou, Pesquisa Clínica e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, Minas Gerais, Brazil.,Centro Federal de Educação Tecnológica de Minas Gerais, Contagem, Minas Gerais, Brazil
| | - Ana Rabello
- Fundação Oswaldo Cruz, Instituto René Rachou, Pesquisa Clínica e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, Minas Gerais, Brazil
| | - Gláucia Cota
- Fundação Oswaldo Cruz, Instituto René Rachou, Pesquisa Clínica e Políticas Públicas em Doenças Infecciosas e Parasitárias, Belo Horizonte, Minas Gerais, Brazil
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Zheng JX, Xia S, Lv S, Zhang Y, Bergquist R, Zhou XN. Infestation risk of the intermediate snail host of Schistosoma japonicum in the Yangtze River Basin: improved results by spatial reassessment and a random forest approach. Infect Dis Poverty 2021; 10:74. [PMID: 34011383 PMCID: PMC8135174 DOI: 10.1186/s40249-021-00852-1] [Citation(s) in RCA: 9] [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: 03/23/2021] [Accepted: 04/23/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Oncomelania hupensis is only intermediate snail host of Schistosoma japonicum, and distribution of O. hupensis is an important indicator for the surveillance of schistosomiasis. This study explored the feasibility of a random forest algorithm weighted by spatial distance for risk prediction of schistosomiasis distribution in the Yangtze River Basin in China, with the aim to produce an improved precision reference for the national schistosomiasis control programme by reducing the number of snail survey sites without losing predictive accuracy. METHODS The snail presence and absence records were collected from Anhui, Hunan, Hubei, Jiangxi and Jiangsu provinces in 2018. A machine learning of random forest algorithm based on a set of environmental and climatic variables was developed to predict the breeding sites of the O. hupensis intermediated snail host of S. japonicum. Different spatial sizes of a hexagonal grid system were compared to estimate the need for required snail sampling sites. The predictive accuracy related to geographic distances between snail sampling sites was estimated by calculating Kappa and the area under the curve (AUC). RESULTS The highest accuracy (AUC = 0.889 and Kappa = 0.618) was achieved at the 5 km distance weight. The five factors with the strongest correlation to O. hupensis infestation probability were: (1) distance to lake (48.9%), (2) distance to river (36.6%), (3) isothermality (29.5%), (4) mean daily difference in temperature (28.1%), and (5) altitude (26.0%). The risk map showed that areas characterized by snail infestation were mainly located along the Yangtze River, with the highest probability in the dividing, slow-flowing river arms in the middle and lower reaches of the Yangtze River in Anhui, followed by areas near the shores of China's two main lakes, the Dongting Lake in Hunan and Hubei and the Poyang Lake in Jiangxi. CONCLUSIONS Applying the machine learning of random forest algorithm made it feasible to precisely predict snail infestation probability, an approach that could improve the sensitivity of the Chinese schistosome surveillance system. Redesign of the snail surveillance system by spatial bias correction of O. hupensis infestation in the Yangtze River Basin to reduce the number of sites required to investigate from 2369 to 1747.
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Affiliation(s)
- Jin-Xin Zheng
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, China
| | - Shang Xia
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine; One Health Center, The University of Edinburgh, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Shan Lv
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine; One Health Center, The University of Edinburgh, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Yi Zhang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, China
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine; One Health Center, The University of Edinburgh, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Robert Bergquist
- Ingerod, Brastad, Sweden/formerly with the UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR), World Health Organization, Geneva, Switzerland
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; NHC Key Laboratory of Parasite and Vector Biology, Shanghai, 200025, China.
- School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine; One Health Center, The University of Edinburgh, Shanghai Jiao Tong University, Shanghai, 200025, China.
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Favre TC, Massara CL, Beck LCNH, Cabello RKSA, Pieri OS. Adherence to diagnosis followed by selective treatment of schistosomiasis mansoni and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to and after the implementation of educational actions. Parasite Epidemiol Control 2021; 13:e00208. [PMID: 33732914 PMCID: PMC7941185 DOI: 10.1016/j.parepi.2021.e00208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/21/2020] [Accepted: 02/25/2021] [Indexed: 11/24/2022] Open
Abstract
Introduction Brazilian guidelines for schistosomiasis elimination recommend regular search of infection carriers and their timely treatment. This study evaluates the effect of educational actions (EAs) among schoolchildren on adherence to diagnosis and treatment, as well as on knowledge of the disease. Methods In April/2013, a questionnaire was applied to 6th-to-8th-grade pupils of eight public schools to evaluate prior knowledge of disease and self-reported risk behavior. Baseline parasitological survey (PS) was done in May/2013, followed by selective treatment and cure assessment. The schools were then randomly allocated to experimental (EG) and control (CG) groups, with and without EAs, respectively. EAs were conducted for 3 months from August/2013. Questionnaire was reapplied in November/2013, April/2014, October/2014, and October/2015 to evaluate changes in knowledge about the disease and self-reported risk behavior. Two further annual PSs (May/2014 and May/2015), each followed by treatment of positives, allowed to evaluate between-group differences and intra-group changes in adherence to diagnosis and treatment, and to follow-up prevalence and intensity of infection. Results Adherence to diagnosis did not differ significantly between EG (84.1%) and CG (81.1%) at baseline but was significantly higher in EG in subsequent PSs. Overall, adherence to treatment was higher than 90% in all three PSs; cure was 98.4%, egg-reduction was 99.8% and reinfection, 2.8%. Prevalence fell significantly in EC (from 23.5% to 6.8%) and CG (from 21.8% to 2.4%), the same occurring with intensity (from 54.2 to 4.6 epg in EG and from 38.4 to 1.3 epg in CG). Disease knowledge increased significantly in EG and CG; knowledge about disease transmission increased significantly more in the EG. Self-reported risk behavior remained above 67% and did not differ significantly between EG and CG. Conclusion EAs increased adherence of schoolchildren and improved knowledge about the disease, confirming that EAs are an important tool to enhance schoolchildren participation in control campaigns. Educational actions improved adherence to stool testing. Disease knowledge also improved with educational actions. Risk behavior stayed high despite educational actions.
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Affiliation(s)
- Tereza Cristina Favre
- Environmental and Health Education Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Cristiano Lara Massara
- Helmintology and Medical Malacology Research Group, René Rachou Institute, Fiocruz, Minas Gerais, Brazil
| | | | | | - Otavio Sarmento Pieri
- Environmental and Health Education Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
- Corresponding author.
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Barry A, Olsson S, Khaemba C, Kabatende J, Dires T, Fimbo A, Minzi O, Bienvenu E, Makonnen E, Kamuhabwa A, Oluka M, Guantai A, van Puijenbroek E, Bergman U, Nkayamba A, Mugisha M, Gurumurthy P, Aklillu E. Comparative Assessment of the Pharmacovigilance Systems within the Neglected Tropical Diseases Programs in East Africa-Ethiopia, Kenya, Rwanda, and Tanzania. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041941. [PMID: 33671293 PMCID: PMC7922898 DOI: 10.3390/ijerph18041941] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 11/16/2022]
Abstract
Monitoring the safety of medicines used in public health programs (PHPs), including the neglected tropical diseases (NTD) program, is a WHO recommendation, and requires a well-established and robust pharmacovigilance system. The objective of this study was to assess the pharmacovigilance systems within the NTD programs in Ethiopia, Kenya, Rwanda, and Tanzania. The East African Community Harmonized Pharmacovigilance Indicators tool for PHPs was used to interview the staff of the national NTD programs. Data on four components, (i) systems, structures, and stakeholder coordination; (ii) data management and signal generation; (iii) risk assessment and evaluation; and (iv) risk management and communication, were collected and analyzed. The NTD programs in the four countries had a strategic master plan, with pharmacovigilance components and mechanisms to disseminate pharmacovigilance information. However, zero individual case safety reports were received in the last 12 months (2017/2018). There was either limited or no collaboration between the NTD programs and their respective national pharmacovigilance centers. None of the NTD programs had a specific budget for pharmacovigilance. The NTD program in all four countries had some safety monitoring elements. However, key elements, such as the reporting of adverse events, collaboration with national pharmacovigilance centers, and budget for pharmacovigilance activity, were limited/missing.
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Affiliation(s)
- Abbie Barry
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden; (A.B.); (S.O.); (U.B.)
| | - Sten Olsson
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden; (A.B.); (S.O.); (U.B.)
| | - Christabel Khaemba
- Pharmacy and Poisons Board, Kenya Lenana Road, P.O. Box 27663-00506 Nairobi, Kenya;
| | - Joseph Kabatende
- Rwanda Food and Drugs Authority, Nyarutarama Plaza, KG 9 Avenue Kigali, Rwanda;
| | - Tigist Dires
- Ethiopian Food and Drug Authority, Africa Avenue, Kirkos Sub City, P.O. Box 5681 Addis Ababa, Ethiopia;
| | - Adam Fimbo
- Tanzania Medicines and Medical Devices Authority, Off Mandela Road, Mabibo, P.O. Box 77150 Dar Es Salaam, Tanzania; (A.F.); (A.N.)
| | - Omary Minzi
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. Box 65013 Dar es Salaam, Tanzania; (O.M.); (A.K.)
| | - Emile Bienvenu
- College of Medicine and Health Sciences, University of Rwanda, KK 737 Kigali, Rwanda; (E.B.); (M.M.)
| | - Eyasu Makonnen
- Department of Pharmacology and Clinical Pharmacy, College of Health Sciences, Addis Ababa University, P.O. Box 9086 Addis Ababa, Ethiopia;
- Center for Innovative Drug Development and Therapeutic Trials for Africa (CDT Africa), College of Health Sciences, Addis Ababa University, P.O. Box 9086 Addis Ababa, Ethiopia
| | - Appolinary Kamuhabwa
- Department of Clinical Pharmacy and Pharmacology, School of Pharmacy, Muhimbili University of Health and Allied Sciences, P. O. Box 65013 Dar es Salaam, Tanzania; (O.M.); (A.K.)
| | - Margaret Oluka
- Department of Pharmacology and Pharmacognosy, School of Pharmacy, University of Nairobi, P.O. Box 19676-00202 Nairobi, Kenya; (M.O.); (A.G.)
| | - Anastasia Guantai
- Department of Pharmacology and Pharmacognosy, School of Pharmacy, University of Nairobi, P.O. Box 19676-00202 Nairobi, Kenya; (M.O.); (A.G.)
| | | | - Ulf Bergman
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden; (A.B.); (S.O.); (U.B.)
| | - Alex Nkayamba
- Tanzania Medicines and Medical Devices Authority, Off Mandela Road, Mabibo, P.O. Box 77150 Dar Es Salaam, Tanzania; (A.F.); (A.N.)
| | - Michael Mugisha
- College of Medicine and Health Sciences, University of Rwanda, KK 737 Kigali, Rwanda; (E.B.); (M.M.)
| | - Parthasarathi Gurumurthy
- Pharmacovigilance and Clinical Trials, Botswana Medicines Regulatory Authority, P.O. Box 505155 Gaborone, Botswana;
| | - Eleni Aklillu
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute, Karolinska University Hospital Huddinge, 141 86 Stockholm, Sweden; (A.B.); (S.O.); (U.B.)
- Correspondence: ; Tel.: +46-735116131
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Li HM, Qian YJ, Yang K, Ding W, Huang LL, Ma XJ, Duan L, Wang DQ, Guan YY, Xiao N, Zhou XN. Assessment of China's contributions to the Regional Network for Asian Schistosomiasis and Other Helminth Zoonoses: a questionnaire survey. Glob Health Res Policy 2021; 6:7. [PMID: 33597021 PMCID: PMC7887806 DOI: 10.1186/s41256-021-00186-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 01/15/2021] [Indexed: 11/30/2022] Open
Abstract
Background The Regional Network for Asian Schistosomiasis and Other Helminth Zoonoses (RNAS+) was established in 1998, which has developed close partnerships with Asian countries endemic for schistosomiasis and other helminthiasis in Asia. RNAS+ has provided an ideal regional platform for policy-makers, practitioners and researchers on the prevention, control and research of parasitic diseases in Asian countries. China, one of the initiating countries, has provided significant technical and financial support to the regional network. However, its roles and contributions have not been explored so far. The purpose of this study was to assess China's contributions on the supporting of RNAS+ development. Methods An assessment research framework was developed to evaluate China’s contributions to RNAS+ in four aspects, including capacity building, funding support, coordination, and cooperation. An anonymous web-based questionnaire was designed to acquire respondents’ basic information, and information on China’s contributions, challenges and recommendations for RNAS+development. Each participant scored from 0 to 10 to assess China’s contribution: “0” represents no contribution, and “10” represents 100% contribution. Participants who included their e-mail address in the 2017–2019 RNAS+ annual workshops were invited to participate in the assessment. Results Of 71 participants enrolled, 41 responded to the survey. 37 (37/41, 90.24%) of them were from RNAS+ member countries, while the other 4 (4/41, 9.76%) were international observers. Most of the respondents (38/41, 92.68%) were familiar with RNAS+. Respondents reported that China’s contributions mainly focused on improving capacity building, providing funding support, coordination responsibility, and joint application of cooperation programs on RNAS+ development. The average scores of China’s contributions in the above four fields were 8.92, 8.64, 8.75, and 8.67, respectively, with an overall assessment score of 8.81 (10 for a maximum score). The challenge of RNAS+ included the lack of sustainable funding, skills, etc. and most participants expressed their continual need of China’s support. Conclusions This survey showed that China has played an important role in the development of RNAS+ since its establishment. This network-type organization for disease control and research can yet be regarded as a great potential pattern for China to enhance regional cooperation. These findings can be used to promote future cooperation between China and other RNAS+ member countries.
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Affiliation(s)
- Hong-Mei Li
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Ying-Jun Qian
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Kun Yang
- Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Wei Ding
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Lu-Lu Huang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Xue-Jiao Ma
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Lei Duan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Duo-Quan Wang
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Ya-Yi Guan
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Ning Xiao
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention; Chinese Center for Tropical Diseases Research; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai, 200025, China.
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Chen C, Guo Q, Fu Z, Liu J, Lin J, Xiao K, Sun P, Cong X, Liu R, Hong Y. Reviews and advances in diagnostic research on Schistosoma japonicum. Acta Trop 2021; 213:105743. [PMID: 33159894 DOI: 10.1016/j.actatropica.2020.105743] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 01/16/2023]
Abstract
Schistosomiasis is an acute and chronic parasitic disease caused by blood flukes (trematode worms) of the genus Schistosoma. Schistosoma japonicum (S. japonicum) infection has decreased significantly in prevalence and intensity of infection in China. However, this disease still remains a serious public health problem in some endemic areas of the Philippines and Indonesia. Thus, more accurate and sensitive methods are much needed for further control of this disease. Here, we review the research progress in techniques for the diagnosis of S. japonicum infection.
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Affiliation(s)
- Cheng Chen
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China
| | - Qinghong Guo
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China
| | - Zhiqiang Fu
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China
| | - Jinming Liu
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China
| | - Jiaojiao Lin
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China
| | - Kai Xiao
- Huancui Development Center for Animal Husbandry, Weihai, 264200, P.R.China
| | - Pengxiang Sun
- Center for Disease Control and Prevention of Huancui, Weihai, 264200, P.R.China
| | - Xiaonan Cong
- Huancui Development Center for Animal Husbandry, Weihai, 264200, P.R.China
| | - Runxia Liu
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA
| | - Yang Hong
- National Reference Laboratory of Animal Schistosomiasis, Key Laboratory of Animal Parasitology of Ministry of Agriculture, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, 200241, P.R.China..
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Abstract
Large-scale control efforts in sub-Saharan Africa may leave long-term lingering transmission. Large-scale screening of snail infection prevalence by loop-mediated isothermal amplification will enable accurate determination of man-to-snail transmission, as well as the effects of biota in snail habitat on host capacity and thus on snail-to-man transmission. Next-generation sequencing will enable identification of gut content of snails and thus their feeding preferences in hot spots and in non–hot spots, as well as for identification of attractive vegetation types for attracting snails to molluscicides.
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Affiliation(s)
- Joseph Hamburger
- Department of Microbiology and Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
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Monnier N, Barth-Jaeggi T, Knopp S, Steinmann P. Core components, concepts and strategies for parasitic and vector-borne disease elimination with a focus on schistosomiasis: A landscape analysis. PLoS Negl Trop Dis 2020; 14:e0008837. [PMID: 33125375 PMCID: PMC7598467 DOI: 10.1371/journal.pntd.0008837] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
Efforts to control and eliminate human schistosomiasis have accelerated over the past decade. In a number of endemic countries and settings, interruption of schistosome transmission has been achieved. In others, Schistosoma infections continue to challenge program managers at different levels, from the complexity of the transmission cycle, over limited treatment options and lack of field-friendly accurate diagnostics, to controversy around adequate intervention strategies. We conducted a landscape analysis on parasitic and vector-borne disease elimination approaches with the aim to identify evidence-based strategies, core components and key concepts for achieving and sustaining schistosomiasis control and for progressing elimination efforts towards interruption of transmission in sub-Saharan Africa. A total of 118 relevant publications were identified from Web of Science, Pubmed and the grey literature and reviewed for their content. In addition, we conducted in-depth interviews with 23 epidemiologists, program managers, policymakers, donors and field researchers. Available evidence emphasizes the need for comprehensive, multipronged and long-term strategies consisting of multiple complementary interventions that must be sustained over time by political commitment and adequate funding in order to reach interruption of transmission. Based on the findings of this landscape analysis, we propose a comprehensive set of intervention strategies for schistosomiasis control and elimination. Before deployment, the proposed interventions will require review, evaluation and validation in the frame of an expert consultation as a step towards adaptation to specific contexts, conditions and settings. Field testing to ensure local relevance and effectiveness is paramount given the diversity of socio-ecological and epidemiological contexts. This landscape analysis explored successful concepts, approaches and interventions of past and ongoing parasitic and vector-borne disease elimination efforts and programs with regard to relevance for progress in the elimination of human schistosome infections. Schistosomiasis is a disabling, water borne parasitic disease of public health concern with an estimated 250 million people infected worldwide. The long-term morbidity of this neglected tropical disease significantly impacts growth, cognition and socioeconomic development at all ages. Despite increased global efforts to control morbidity and advance elimination, challenges in view of the complex life cycle which involves freshwater sources, intermediate snail hosts and humans, remain. This calls for targeted interventions and concerted programs. According to the evidence from the literature and as proposed by a wide range of key informants, comprehensive, multipronged and long-term strategies supported by strong political commitment and adequate funding are required in order to achieve and sustain the set goals. Based on the findings, we propose here a comprehensive set of intervention strategies for schistosomiasis control and elimination for review and evaluation to inform implementation research needs and elimination program design.
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Affiliation(s)
- Nora Monnier
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
| | - Tanja Barth-Jaeggi
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Peter Steinmann
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
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Buchter V, Ong YC, Mouvet F, Ladaycia A, Lepeltier E, Rothlisberger U, Keiser J, Gasser G. Multidisciplinary Preclinical Investigations on Three Oxamniquine Analogues as New Drug Candidates for Schistosomiasis**. Chemistry 2020; 26:15232-15241. [DOI: 10.1002/chem.202002856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/24/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Valentin Buchter
- Swiss Tropical and Public Health Institute Socinstrasse 57, P.O. box 4002 Basel Switzerland
- University of Basel Petersplatz 1, P.O. Box 4001 Basel Switzerland
| | - Yih Ching Ong
- Chimie ParisTech PSL University CNRS, Institute of Chemistry for Life and Health Sciences Laboratory of Inorganic Chemical Biology 75005 Paris France
| | - François Mouvet
- Laboratory of Computational Chemistry and Biochemistry EPFL 1015 Lausanne Switzerland
| | - Abdallah Ladaycia
- MINT, UNIV Angers, INSERM 1066, CNRS 6021 Université Bretagne Loire 4 rue Larrey 49933 Angers Cedex 9 France
| | - Elise Lepeltier
- MINT, UNIV Angers, INSERM 1066, CNRS 6021 Université Bretagne Loire 4 rue Larrey 49933 Angers Cedex 9 France
| | - Ursula Rothlisberger
- Laboratory of Computational Chemistry and Biochemistry EPFL 1015 Lausanne Switzerland
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute Socinstrasse 57, P.O. box 4002 Basel Switzerland
- University of Basel Petersplatz 1, P.O. Box 4001 Basel Switzerland
| | - Gilles Gasser
- Chimie ParisTech PSL University CNRS, Institute of Chemistry for Life and Health Sciences Laboratory of Inorganic Chemical Biology 75005 Paris France
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Therapeutic Effect of Diminazene Aceturate on Parasitic Blood Fluke Schistosoma mansoni Infection. Antimicrob Agents Chemother 2020; 64:AAC.01372-20. [PMID: 32816737 DOI: 10.1128/aac.01372-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/13/2020] [Indexed: 01/30/2023] Open
Abstract
Praziquantel is currently the only drug available to treat schistosomiasis, a disease of enormous public health significance caused by a blood fluke of the genus Schistosoma Diminazene, a drug approved by the FDA, has been successfully used to treat diseases caused by blood protozoan parasites. In this study, we evaluated the antiparasitic properties of diminazene against Schistosoma mansoni ex vivo and in mice harboring either chronic or early S. mansoni infections. In vitro, we monitored phenotypic and tegumental changes as well as the effects of the drug on pairing and egg production. In mice infected with either adult (chronic infection) or immature (early infection) worms, diminazene was administered intraperitoneally (10 to 100 mg/kg of body weight) or by oral gavage (100 to 400 mg/kg), and we studied the influence of the drug on worm burden and egg production. Liver and spleen pathologies and serum aminotransferase levels were also analyzed. In vitro, 50% effective concentrations (EC50) and EC90 revealed that diminazene is able to kill both immature and adult parasites, and its effect was time and concentration dependent. In addition, confocal laser scanning microscopy showed morphological alterations in the teguments of schistosomes. In an animal model, the influence of the drug on worm burden, egg production, hepatomegaly, and splenomegaly depended on the dosing regimen applied and the route of administration. Diminazene also caused a significant reduction in aminotransferase levels. Comparatively, diminazene treatment was more effective in chronic infection than in early infection. In tandem, our study revealed that diminazene possesses anthelmintic properties and inhibits liver injury caused by Schistosoma eggs.
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Keller D, Rothen J, Dangy JP, Saner C, Daubenberger C, Allan F, Ame SM, Ali SM, Kabole F, Hattendorf J, Rollinson D, Seyfarth R, Knopp S. Performance of a real-time PCR approach for diagnosing Schistosoma haematobium infections of different intensity in urine samples from Zanzibar. Infect Dis Poverty 2020; 9:128. [PMID: 32887642 PMCID: PMC7487541 DOI: 10.1186/s40249-020-00726-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/14/2020] [Indexed: 12/17/2022] Open
Abstract
Background Efforts to control and eliminate schistosomiasis have accelerated over the past decade. As parasite burden, associated morbidity and egg excretion decrease, diagnosis with standard parasitological methods becomes harder. We assessed the robustness and performance of a real-time PCR (qPCR) approach in comparison with urine filtration microscopy and reagent strip testing for the diagnosis of Schistosoma haematobium infections of different intensities. Methods The robustness of DNA isolation and qPCR was validated in eight laboratories from Europe and Africa. Subsequently, 792 urine samples collected during cross-sectional surveys of the Zanzibar Elimination of Schistosomiasis Transmission (ZEST) project in 2012–2017 were examined with qPCR in 2018. Diagnostic sensitivity of the qPCR was calculated at different infection intensity categories, using urine filtration microscopy as reference test. Spearman’s rank correlation between Ct-values and S. haematobium egg counts was assessed and Ct-value percentiles for infection intensity categories determined. Results S. haematobium Dra1 DNA-positive samples were identified correctly in all eight laboratories. Examination of urine samples from Zanzibar revealed Dra1 DNA in 26.8% (212/792) by qPCR, S. haematobium eggs in 13.3% (105/792) by urine filtration, and microhaematuria in 13.8% (109/792) by reagent strips. Sensitivity of the qPCR increased with augmenting egg counts: 80.6% (29/36) for counts between 1 and 4 eggs, 83.3% (15/18) for counts between 5 and 9 eggs, 100% (23/23) for counts between 10 and 49 eggs, and 96.4% (27/28) for counts of 50+ eggs. There was a significant negative correlation between Ct-values and egg counts (Spearman’s rho = − 0.49, P < 0.001). Seventy-five percent of the Ct-values were ≥ 33 in the egg-negative category, < 31 in the light intensity category, and < 24 in the heavy intensity category. Conclusions While the sensitivity of the qPCR was ~ 80% for very light intensity infections (egg counts < 10), in general, the Dra1 based qPCR assay detected twice as many S. haematobium infections compared with classical parasitological tests. The qPCR is hence a sensitive, urine-based approach for S. haematobium diagnosis that can be used for impact assessment of schistosomiasis elimination programmes, individual diagnosis, and in improved format also for verification and certification of elimination. Trial registration ISRCTN, ISRCTN48837681. Registered 05 September 2012 - Retrospectively registered.
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Affiliation(s)
| | - Julian Rothen
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Jean-Pierre Dangy
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Corina Saner
- Biolytix AG, Benkenstrasse 254, 4108, Witterswil, Switzerland
| | - Claudia Daubenberger
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - Fiona Allan
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Shaali M Ame
- Public Health Laboratory Ivo de Carneri, P.O. Box 122, Chake-Chake, Pemba, United Republic of Tanzania
| | - Said M Ali
- Public Health Laboratory Ivo de Carneri, P.O. Box 122, Chake-Chake, Pemba, United Republic of Tanzania
| | - Fatma Kabole
- Neglected Diseases Programme, Ministry of Health, P.O. Box 236, Zanzibar Town, Unguja, United Republic of Tanzania
| | - Jan Hattendorf
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland.,University of Basel, Petersplatz 1, 4001, Basel, Switzerland
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Ralf Seyfarth
- Biolytix AG, Benkenstrasse 254, 4108, Witterswil, Switzerland
| | - Stefanie Knopp
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4002, Basel, Switzerland. .,University of Basel, Petersplatz 1, 4001, Basel, Switzerland.
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Balahbib A, Amarir F, Bouhout S, Adlaoui EB, Rhajaoui M, Sadak A. Retrospective study on imported schistosomiasis in Morocco between 2005 and 2017. Trop Doct 2020; 50:317-321. [PMID: 32501173 DOI: 10.1177/0049475520928195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Since 2004, no indigenous cases of schistosomiasis have been found in Morocco; only imported cases have been detected. The aim of the present study was to describe and analyse the epidemiological profile of imported schistosomiasis between 2005 and 2017, and, by this, attract attention to the probability of a reintroduction of this disease. During this period, 27 cases were recorded in Morocco, with a male predominance (13:1). All cases reported were found among African immigrants from Mauritania (37%), Mali (18%) and Senegal (15%). Schistosoma heamatobium was the most dominant specie. Most cases were reported in Rabat and Agadir, where there are many snail habitats. To prevent a re-emergence of the disease, the main challenge would be to consolidate and maintain a sustainable surveillance and control system of the importation of bilharzia. The frequency of asymptomatic schistosomiasis justifies a systematic health check-up for all travellers, migrants and immigrants.
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Affiliation(s)
- Abdelaali Balahbib
- Ph.D student Laboratory of Biodiversity, Ecology and genome, Faculty of Sciences, Mohammed V University in Rabat, Morocco.,Ph.D student, National Reference Laboratory of Schistosomiasis and Malacology, National Institute of Hygiene, Agdal, Rabat, Morocco
| | - Fatima Amarir
- Professor, Laboratory of Immunity and Biodiversity, Department of Biology, Faculty of Sciences Aïn Chock, University Hassan II, Casablanca, Morocco
| | - Souad Bouhout
- Doctor, Direction of Epidemiology and Disease Control (DELM), Ministry of Health, Rabat, Morocco
| | - El Bachir Adlaoui
- Doctor, National Reference Laboratory of Schistosomiasis and Malacology, National Institute of Hygiene, Agdal, Rabat, Morocco
| | - Mohamed Rhajaoui
- Doctor, National Reference Laboratory of Schistosomiasis and Malacology, National Institute of Hygiene, Agdal, Rabat, Morocco
| | - Abderrahim Sadak
- Professor, Laboratory of Biodiversity, Ecology and genome, Faculty of Sciences, Mohammed V University in Rabat, Morocco
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Taylor EM. NTD Diagnostics for Disease Elimination: A Review. Diagnostics (Basel) 2020; 10:E375. [PMID: 32517108 PMCID: PMC7344624 DOI: 10.3390/diagnostics10060375] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/07/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022] Open
Abstract
Neglected Tropical Diseases (NTDs) marked out for disease elimination provide a lens through which to explore the changing status of diagnosis in global health. This paper reports on the findings of a scoping review, which set out to explore the main debates around diagnosis for the elimination of NTDs, including the multiple roles diagnostic technologies are being ascribed and the ideal characteristics of tests. It also attempts to summarise the state of diagnosis for three NTDs with elimination goals. The review places special emphasis on point-of-care testing in acknowledgement of the remote and underserved areas where NTDs proliferate. Early NTD campaigns were largely focused on attack phase planning, whereby a similar set of interventions could be transplanted anywhere. Now, with elimination goals in sight, strategies must be tailored to local settings if they are to attain and sustain success. Diagnostic data helps with local adaptation and is increasingly used for programmatic decision-making. The review finds that elimination goals reframe whom diagnosis is for and the myriad roles diagnostics can play. The exigencies of elimination also serve to highlight deficiencies in the current diagnostic arsenal and development pipeline for many NTDs. Moving forward, a guiding framework is needed to drive research and stimulate investment in diagnosis to support NTD goals.
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Affiliation(s)
- Emma Michelle Taylor
- Department of Social Anthropology, University of Edinburgh, Edinburgh EH8 9LD, UK
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40
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Accuracy of real-time polymerase chain reaction to detect Schistosoma mansoni - infected individuals from an endemic area with low parasite loads. Parasitology 2020; 147:1140-1148. [PMID: 32484122 DOI: 10.1017/s003118202000089x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Due to the efforts to control schistosomiasis transmission in tropical countries, a large proportion of individuals from endemic areas present low parasite loads, which hinders diagnosis of intestinal schistosomiasis by the Kato-Katz (KK) method. Therefore, the development of more sensitive diagnostic methods is essential for efficient control measures. The aim was to evaluate the accuracy of a real-time polymerase chain reaction (RT-PCR) to detect Schistosoma mansoni DNA in fecal samples of individuals with low parasite loads. A cross-sectional population-based study was conducted in a rural community (n = 257) in Brazil. POC-CCA® was performed in urine and feces were used for RT-PCR. In addition, fecal exams were completed by 18 KK slides, saline gradient and Helmintex techniques. The combined results of the three parasitological tests detected schistosome eggs in 118 participants (45.9%) and composed the consolidated reference standard (CRS). By RT-PCR, 117 out of 215 tested samples were positive, showing 91.4% sensitivity, 80.2% specificity and good concordance with the CRS (kappa = 0.71). RT-PCR identified 86.9% of the individuals eliminating less than 12 eggs/g of feces, demonstrating much better performance than POC-CCA® (50.8%). Our results showed that RT-PCR is a valuable alternative for the diagnosis of intestinal schistosomiasis in individuals with very low parasite loads.
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41
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Amoah AS, Hoekstra PT, Casacuberta-Partal M, Coffeng LE, Corstjens PLAM, Greco B, van Lieshout L, Lim MD, Markwalter CF, Odiere MR, Reinhard-Rupp J, Roestenberg M, Stothard R, Tchuem Tchuenté LA, de Vlas SJ, van Dam GJ. Sensitive diagnostic tools and targeted drug administration strategies are needed to eliminate schistosomiasis. THE LANCET. INFECTIOUS DISEASES 2020; 20:e165-e172. [PMID: 32595046 DOI: 10.1016/s1473-3099(20)30254-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 03/03/2020] [Accepted: 03/23/2020] [Indexed: 11/29/2022]
Abstract
Although preventive chemotherapy has been instrumental in reducing schistosomiasis incidence worldwide, serious challenges remain. These problems include the omission of certain groups from campaigns of mass drug administration, the existence of persistent disease hotspots, and the risk of recrudescent infections. Central to these challenges is the fact that the diagnostic tools currently used to establish the burden of infection are not sensitive enough, especially in low-endemic settings, which results in underestimation of the true prevalence of active Schistosoma spp infections. This central issue necessitates that the current schistosomiasis control strategies recommended by WHO are re-evaluated and, possibly, adapted. More targeted interventions and novel approaches have been used to estimate the prevalence of schistosomiasis, such as establishing infection burden by use of precision mapping, which provides high resolution spatial information that delineates variations in prevalence within a defined geographical area. Such information is instrumental in guiding targeted intervention campaigns. However, the need for highly accurate diagnostic tools in such strategies is a crucial factor that is often neglected. The availability of highly sensitive diagnostic tests also opens up the possibility of applying strategies of sample pooling to reduce the cost of control programmes. To interrupt the transmission of, and eventually eliminate, schistosomiasis, better local targeting of preventive chemotherapy, in combination with highly sensitive diagnostic tools, is crucial.
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Affiliation(s)
- Abena S Amoah
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK; Malawi Epidemiology and Intervention Research Unit, Chilumba, Malawi
| | - Pytsje T Hoekstra
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands.
| | | | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Paul L A M Corstjens
- Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands
| | | | - Lisette van Lieshout
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
| | - Mark D Lim
- Global Health Division, The Bill & Melinda Gates Foundation, Seattle, WA, USA; Global Public Health Programs, American Society for Microbiology, Washington DC, USA
| | - Christine F Markwalter
- Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Maurice R Odiere
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | | | - Meta Roestenberg
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands; Department of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | | | - Louis-Albert Tchuem Tchuenté
- Laboratory of Parasitology and Ecology, University of Yaoundé I, Yaoundé, Cameroon; Centre for Schistosomiasis and Parasitology, Yaoundé, Cameroon
| | - Sake J de Vlas
- Department of Public Health, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Govert J van Dam
- Department of Parasitology, Leiden University Medical Center, Leiden, Netherlands
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42
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Butrous G. Pulmonary hypertension: From an orphan disease to a global epidemic. Glob Cardiol Sci Pract 2020; 2020:e202005. [PMID: 33150150 PMCID: PMC7590934 DOI: 10.21542/gcsp.2020.5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/11/2020] [Indexed: 01/01/2023] Open
Abstract
[No abstract. Showing first paragraph of article]Pulmonary hypertension is a progressive disease characterized by an elevation of pulmonary artery pressure and pulmonary vascular resistance, leading to right ventricular failure and death. It remains a challenging chronic progressive disease, but the current interest and advent of medical therapy in the last 20 years has significantly changed the perception of medical community in this disease. Pulmonary hypertension is not a specific disease; the majority of cases present with other diseases and various pathological processes that affect the pulmonary vasculature, and consequently increase pulmonary pressure and vascular resistance.
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Affiliation(s)
- Ghazwan Butrous
- Medway School of Pharmacy University of Kent at Canterbury, UK
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43
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Cunningham LJ, Campbell SJ, Armoo S, Koukounari A, Watson V, Selormey P, Stothard JR, Idun B, Asiedu M, Ashong Y, Adams ER, Osei-Atweneboana MY. Assessing expanded community wide treatment for schistosomiasis: Baseline infection status and self-reported risk factors in three communities from the Greater Accra region, Ghana. PLoS Negl Trop Dis 2020; 14:e0007973. [PMID: 32339185 PMCID: PMC7205311 DOI: 10.1371/journal.pntd.0007973] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 05/07/2020] [Accepted: 12/05/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND This paper reports on the baseline prevalence and associated risk factor findings of a pilot, longitudinal study exploring community-wide treatment of schistosomiasis and soil-transmitted helminthiasis, using albendazole plus praziquantel in the Greater Accra region of Ghana. METHOD From three communities, at least, 658 individuals were enrolled into the study via random household selection. Prevalence and intensity of schistosomiasis and STH infection were determined from stool and urine samples with a questionnaire being administered in order to explore other morbidities and risk factors. Factor analysis of household demographic variables was undertaken to generate a socioeconomic score; this was then further categorised into tertiles. Proportional-odds cumulative logit generalised estimating equation (GEE) models were used to investigate categorical ordinal intensity of infection associations with morbidity. Separately, logistic GEE models were used to investigate risk factor associations with infection prevalence. RESULTS Both Schistosoma haematobium and S. mansoni were prevalent in the three communities, with the prevalence of S. haematobium ranging from 3.3% (24/679; 95% CI = 1.9-4.7) to 19% (114/632; 95% CI = 15.8-22.2) and S. mansoni ranging from 30% (202/679; 95% CI = 26.5-33.5) to 78.3% (409/536; 95% CI = 74.7-81.9). The total prevalence of STH across all three sites was negligible at 1.3% (24/1847; 95% CI = 0.8-1.9) comprising mainly hookworm (10/1847). Multivariable statistical models indicated males to be 2.3 (95% CI = 1.7-3.3) times more likely to have a high intensity S. mansoni infection and 1.5 (95% CI = 1.1-2) times more likely to have a high intensity of S. haematobium infection compared to females. There was no significant difference in the likelihood of infection with S. mansoni between adults and school age children (SAC), however S. haematobium infections were found to be 2.5 (95% CI = 1.8-3.5) times more likely to occur in school age children than in adults. Multivariable statistical models (adjusted for age and sex) indicated an association between schistosomiasis and a number of self-reported morbidity indicators (notably diarrhoea and blood in stool and urine). Low socio-economic status was also associated with SCH infection (OR: 2; 95% CI = 1.3-3.2). CONCLUSION The communities targeted by this study showed a range of Schistosoma prevalence's of infection, from hypo-endemic through to meso-endemic and hyper-endemic. The prevalence of SCH across the different age groups in the study locations highlights the large number of individuals currently being left out of the standard morbidity control method of annual treatment of the SAC.
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Affiliation(s)
- Lucas J. Cunningham
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Samuel Armoo
- Department of Biomedical and Public Health Research, Council for Scientific and Industrial Research—Water Research Institute, Council Close, Accra, Ghana
| | - Artemis Koukounari
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Victoria Watson
- Department of Biostatistics, University of Liverpool, Liverpool, United Kingdom
| | - Pamela Selormey
- Department of Biomedical and Public Health Research, Council for Scientific and Industrial Research—Water Research Institute, Council Close, Accra, Ghana
| | - J. Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bright Idun
- Department of Biomedical and Public Health Research, Council for Scientific and Industrial Research—Water Research Institute, Council Close, Accra, Ghana
| | - Manfred Asiedu
- Department of Biomedical and Public Health Research, Council for Scientific and Industrial Research—Water Research Institute, Council Close, Accra, Ghana
| | - Yvonne Ashong
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Emily R. Adams
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Mike Yaw Osei-Atweneboana
- Department of Biomedical and Public Health Research, Council for Scientific and Industrial Research—Water Research Institute, Council Close, Accra, Ghana
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Mogeni P, Vandormael A, Cuadros D, Appleton C, Tanser F. Impact of community piped water coverage on re-infection with urogenital schistosomiasis in rural South Africa. eLife 2020; 9:54012. [PMID: 32178761 PMCID: PMC7108860 DOI: 10.7554/elife.54012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 03/10/2020] [Indexed: 12/15/2022] Open
Abstract
Previously, we demonstrated that coverage of piped water in the seven years preceding a parasitological survey was strongly predictive of Schistosomiasis haematobium infection in a nested cohort of 1976 primary school children (Tanser, 2018). Here, we report on the prospective follow up of infected members of this nested cohort (N = 333) for two successive rounds following treatment. Using a negative binomial regression fitted to egg count data, we found that every percentage point increase in piped water coverage was associated with 4.4% decline in intensity of re-infection (incidence rate ratio = 0.96, 95% CI: 0.93–0.98, p=0.004) among the treated children. We therefore provide further compelling evidence in support of the scaleup of piped water as an effective control strategy against Schistosoma haematobium transmission.
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Affiliation(s)
- Polycarp Mogeni
- Africa Health Research Institute, KwaZulu-Natal, South Africa.,School of Nursing and Public Health, University of KwaZulu-Natal, KwaZulu-Natal, South Africa.,KwaZulu-Natal Innovation and Sequencing Platform (KRISP), University of KwaZulu-Natal, KwaZulu-Natal, South Africa
| | - Alain Vandormael
- Africa Health Research Institute, KwaZulu-Natal, South Africa.,School of Nursing and Public Health, University of KwaZulu-Natal, KwaZulu-Natal, South Africa.,KwaZulu-Natal Innovation and Sequencing Platform (KRISP), University of KwaZulu-Natal, KwaZulu-Natal, South Africa.,Heidelberg Institute of Global Health, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany
| | - Diego Cuadros
- Department of Geography and Geographic Information Science, University of Cincinnati, Cincinnati, United States.,Health Geography and Disease Modeling Laboratory, University of Cincinnati, Cincinnati, United States
| | - Christopher Appleton
- School of Life Sciences, University of KwaZulu-Natal, KwaZulu-Natal, South Africa
| | - Frank Tanser
- Africa Health Research Institute, KwaZulu-Natal, South Africa.,School of Nursing and Public Health, University of KwaZulu-Natal, KwaZulu-Natal, South Africa.,Lincoln International Institute for Rural Health, University of Lincoln, Lincoln, United Kingdom
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Famakinde DO. Public health concerns over gene-drive mosquitoes: will future use of gene-drive snails for schistosomiasis control gain increased level of community acceptance? Pathog Glob Health 2020; 114:55-63. [PMID: 32100643 DOI: 10.1080/20477724.2020.1731667] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
With the advent of CRISPR (clustered regularly interspaced short palindromic repeat)-based gene drive, present genetic research in schistosomiasis vector control envisages the breeding and release of transgenic schistosome-resistant (TSR) snail vectors to curb the spread of the disease. Although this approach is still in its infancy, studies focussing on production of genetically modified (GM) mosquitoes (including gene-drive mosquitoes) are well advanced and set the pace for other transgenic vector research. Unfortunately, as with other GM mosquitoes, open field release of gene-drive mosquitoes is currently challenged in part by some concerns such as gene drive failure and increased transmission potential for other mosquito-borne diseases among others, which might have adverse effects on human well-being. Therefore, not only should we learn from the GM mosquito protocols, frameworks and guidelines but also appraise the applicability of its current hurdles to other transgenic vector systems, such as the TSR snail approach. Placing these issues in a coherent comparative perspective, I argue that although the use of TSR snails may face similar technical, democratic and diplomatic challenges, some of the concerns over gene-drive mosquitoes may not apply to gene-drive snails, proposing a theory that community consent will be no harder and possibly easier to obtain for TSR snails than the experience with GM mosquitoes. In the future, these observations may help public health practitioners and policy makers in effective communication with communities on issues regarding the use of TSR snails to interrupt schistosomiasis transmission, especially in sub-Saharan Africa.
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Affiliation(s)
- Damilare O Famakinde
- Department of Medical Microbiology and Parasitology, University of Lagos, Lagos, Nigeria
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46
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Synthesis and Bioactivity of Phthalimide Analogs as Potential Drugs to Treat Schistosomiasis, a Neglected Disease of Poverty. Pharmaceuticals (Basel) 2020; 13:ph13020025. [PMID: 32028743 PMCID: PMC7169845 DOI: 10.3390/ph13020025] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 12/23/2022] Open
Abstract
The neglected tropical disease, schistosomiasis, is caused by trematode blood flukes of the Schistosoma genus and infects approximately 200 million people worldwide. With just one partially effective drug available for disease treatment, new drugs are urgently needed. Herein, a series of 47 phthalimide (Pht) analogues possessing high-value bioactive scaffolds (i.e., benzimidazole and 1,2,3,-triazoles) was synthesized by click-chemistry. Compounds were evaluated for anti-schistosomal activity in culture against somules (post-infective larvae) and adults of Schistosoma mansoni, their predicted ADME (absorption, distribution, metabolism, and excretion) properties, and toxicity vs. HepG2 cells. The majority showed favorable parameters for surface area, lipophilicity, bioavailability and Lipinski score. Thirteen compounds were active at 10 µM against both somules and adults (6d, 6f, 6i–6l, 6n–6p, 6s, 6r’, 6t’ and 6w). Against somules, the majority caused degeneracy and/or death after 72 h; whereas against adult parasites, five compounds (6l, 6d, 6f, 6r’ and 6s) elicited degeneracy, tegumental (surface) damage and/or death. Strongest potency against both developmental stages was recorded for compounds possessing n-butyl or isobutyl as a linker, and a pentafluorophenyl group on triazole. Apart from five compounds for which anti-parasite activity tracked with toxicity to HepG2 cells, there was apparently no toxicity to HepG2 cells (EC50 values ≥50 µM). The data overall suggest that phthaloyl-triazole compounds are favorable synthons for additional studies as anti-schistosomals.
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Saelens G, Gabriël S. Currently Available Monitoring and Surveillance Systems for Taenia spp., Echinococcus spp., Schistosoma spp., and Soil-Transmitted Helminths at the Control/Elimination Stage: A Systematic Review. Pathogens 2020; 9:E47. [PMID: 31935916 PMCID: PMC7168685 DOI: 10.3390/pathogens9010047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/02/2020] [Accepted: 01/02/2020] [Indexed: 12/13/2022] Open
Abstract
An increasing global focus on neglected tropical diseases (NTDs) has resulted in the set up of numerous control and elimination activities worldwide. This is partly true for Taenia solium taeniasis/cysticercosis, the most important foodborne parasitic infection. Despite substantial progress, adequate monitoring and surveillance (M&S) are required to sustain a status of control/elimination. This is often lacking, especially for T. solium. Therefore, the objective was to conduct a systematic literature review of the currently available M&S systems at the control/elimination stage of the four top-ranked helminth NTDs. Specifically, Taenia spp., Echinococcus spp., Schistosoma spp., and soil-transmitted helminths (STHs) were considered to determine if there are any similarities between their M&S systems and whether certain approaches can be adopted from each other. The systematic review demonstrated that rigorous M&S systems have been designed for the control/elimination stage of both STHs and schistosomiasis, particularly in China. On the other hand, a concept of M&S for Taenia spp. and Echinococcus spp. has not been fully developed yet, due to a lack of epidemiological data and the fact that many endemic countries are far away from reaching control/elimination. Moreover, accurate diagnostic tools for all four diseases are still imperfect, which complicates proper M&S. Finally, there is an urgent need to develop and harmonize/standardize M&S activities in order to reliably determine and compare the epidemiological situation worldwide.
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Affiliation(s)
- Ganna Saelens
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke B-9820, Belgium
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Kamdem SD, Konhawa F, Kuemkon EM, Meyo Kamguia L, Tchanana GK, Nche F, Oumarou A, Hamza M, Ouratou Y, Tcheutchoua MN, Ghislain Essomba R, Ngogang MP, Kengne M, Netongo PM, Ondigui BE, Okomo Assoumou MC, Brombacher F, Nono JK. Negative Association of Interleukin-33 Plasma Levels and Schistosomiasis Infection in a Site of Polyparasitism in Rural Cameroon. Front Immunol 2019; 10:2827. [PMID: 31849991 PMCID: PMC6901687 DOI: 10.3389/fimmu.2019.02827] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 11/18/2019] [Indexed: 12/20/2022] Open
Abstract
Background: This study aimed to investigate the association of plasma levels of IL-33, a mucosal alarmin known to elicit type-2 immunity, with infection and liver fibrosis profiles of school children from an endemic area for Schistosoma mansoni, malaria and hepatitis (B & C) in rural Cameroon. Methods: A cross-sectional study enrolling schoolchildren from 5 public schools was conducted. Single schistosomiasis, malaria and hepatitis infections or co-infections were assessed by kato katz, microscopy, and rapid diagnostic tests, respectively. Hepatic fibrosis was assessed by ultrasound according to WHO Niamey guidelines and plasma levels of Interleukin 33 were determined by ELISA. All statistics were performed using R studio software. Principal findings: We found a prevalence of 13.5% (37/275), 18.2% (50/275), and 8% (22/275), respectively for schistosomiasis, malaria and hepatitis (B or C) single infections. Only 7.6% (21/275) of co-infections were reported. Although Plasma IL-33 showed a minimal negative risk for schistosomiasis infection (AOR 0.99; 95% CI 0.97–1.01), S. mansoni infected participants had lower levels of plasma IL-33 (p = 0.003) which decreased significantly as eggs burdens increased (p = 0.01) with a negative Pearson coefficient of r = −0.22. Hepatic fibrosis occurred in 47.3% (130/275) of our study population independently from plasma levels of IL-33 (AOR 1.00; 95% CI 0.99–1.01). Conclusion/Significance: Our data failed to show an association between plasma IL-33 levels and liver disease but convincingly report on a negative association between plasma IL-33 levels and schistosomiasis infection and egg burden in school children from a polyparasitic schistosomiasis endemic area.
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Affiliation(s)
- Severin Donald Kamdem
- Division of Immunology, Health Science Faculty, University of Cape Town, Cape Town, South Africa.,Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Immunology of Infectious Diseases Unit, South African Medical Research Centre, Cape Town, South Africa
| | - Francis Konhawa
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon
| | - Erve Martial Kuemkon
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon
| | - Leonel Meyo Kamguia
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon
| | - Gladys K Tchanana
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon.,CIAB EXACT Medical Laboratory, Yaoundé, Cameroon
| | - Frungwa Nche
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
| | | | | | - Yasmine Ouratou
- Biotechnology Centre, University of Yaoundé 1, Yaoundé, Cameroon
| | | | - René Ghislain Essomba
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon.,National Public Health Laboratory, Ministry of Public Health, Yaoundé, Cameroon
| | | | - Michel Kengne
- School of Health Sciences, Catholic University of Central Africa, Yaoundé, Cameroon
| | - Palmer Masumbe Netongo
- Biotechnology Centre, University of Yaoundé 1, Yaoundé, Cameroon.,Department of Biochemistry, University of Yaoundé 1, Yaoundé, Cameroon
| | | | | | - Frank Brombacher
- Division of Immunology, Health Science Faculty, University of Cape Town, Cape Town, South Africa.,Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Immunology of Infectious Diseases Unit, South African Medical Research Centre, Cape Town, South Africa.,Wellcome Centre for Infectious Diseases Research in Africa, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Cape Town, South Africa
| | - Justin Komguep Nono
- Division of Immunology, Health Science Faculty, University of Cape Town, Cape Town, South Africa.,Cape Town Component, International Centre for Genetic Engineering and Biotechnology, Cape Town, South Africa.,Immunology of Infectious Diseases Unit, South African Medical Research Centre, Cape Town, South Africa.,The Medical Research Centre, Institute of Medical Research and Medicinal Plant Studies, Ministry of Scientific Research and Innovation, Yaoundé, Cameroon
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Tumwebaze I, Clewing C, Dusabe MC, Tumusiime J, Kagoro-Rugunda G, Hammoud C, Albrecht C. Molecular identification of Bulinus spp. intermediate host snails of Schistosoma spp. in crater lakes of western Uganda with implications for the transmission of the Schistosoma haematobium group parasites. Parasit Vectors 2019; 12:565. [PMID: 31775865 PMCID: PMC6882369 DOI: 10.1186/s13071-019-3811-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 11/15/2019] [Indexed: 12/05/2022] Open
Abstract
Background Human schistosomiasis is the second most important tropical disease and occurs in two forms in Africa (intestinal and urogenital) caused by the digenetic trematodes Schistosoma mansoni and Schistosoma haematobium, respectively. A proposed recent shift of schistosomiasis above a previously established altitudinal threshold of 1400 m above sea level in western Ugandan crater lakes has triggered more research interest there. Methods Based on extensive field sampling in western Uganda and beyond and employing an approach using sequences of the mitochondrial barcoding gene cytochrome c oxidase subunit 1 (cox1) this study aims were: (i) identification and establishment of the phylogenetic affinities of Bulinus species as potential hosts for Schistosoma spp.; (ii) determining diversity, frequency and distribution patterns of Bulinus spp.; and (iii) establishing genetic variability and phylogeographical patterns using Bayesian inference and parsimony network analyses. Results Out of the 58 crater lakes surveyed, three species of Bulinus snails were found in 34 crater lakes. Bulinus tropicus was dominating, Bulinus forskalii was found in two lakes and Bulinus truncatus in one. The latter two species are unconfirmed potential hosts for S. haematobium in this region. However, Bulinus tropicus is an important species for schistosomiasis transmission in ruminants. Bulinus tropicus comprised 31 haplotypes while both B. forskalii and B. truncatus exhibited only a single haplotype in the crater lakes. All species clustered with most of the haplotypes from surrounding lake systems forming source regions for the colonization of the crater lakes. Conclusions This first detailed malacological study of the crater lakes systems in western Uganda revealed presence of Bulinus species that are either not known or not regionally known to be hosts for S. haematobium, the causing agent of human urogenital schistosomiasis. Though this disease risk is almost negligible, the observed dominance of B. tropicus in the crater lakes shows that there is a likelihood of a high risk of infections with Schistosoma bovis. Thus, extra attention should be accorded to safeguard wild and domestic ruminants in this region as the population benefits from these animals.
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Affiliation(s)
- Immaculate Tumwebaze
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany.
| | - Catharina Clewing
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany
| | | | - Julius Tumusiime
- Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Grace Kagoro-Rugunda
- Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Cyril Hammoud
- Department of Biology, Royal Museum for Central Africa, Leuvensesteenweg 13, 3080, Tervuren, Belgium.,Limnology Research Unit, Ghent University, K. L. Ledeganckstraat 35, 9000, Ghent, Belgium
| | - Christian Albrecht
- Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany.,Department of Biology, Mbarara University of Science and Technology, Mbarara, Uganda
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Spatiotemporal pattern analysis of schistosomiasis based on village level in the transmission control stage in lake and marshland areas in China. Parasitology 2019; 147:199-212. [PMID: 31699184 DOI: 10.1017/s0031182019001537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hubei Province is one of the endemic regions with severe schistosomiasis in China. To eliminate schistosomiasis in lake and marshland regions, this study detected hotspots of schistosomiasis cases both spatially and spatiotemporally on the basis of spatial autocorrelation; clustering and outlier, purely spatial and spatiotemporal cluster analyses at the village level from 2013 to 2017 in Hubei Province. The number of cases confirmed positive by an immunodiagnostic test and etiological diagnosis and advanced schistosomiasis cases dramatically declined during the study period. Significant global spatial autocorrelation of schistosomiasis patients was found at the village level in the whole province in 5 years. Clustering and outlier analysis showed that most HH villages were mainly concentrated along the Yangtze River, especially in Jianghan Plain. Spatial and spatiotemporal cluster analyses showed that significant clusters of the schistosomiasis cases were detected at the village level. In general, space and spatiotemporal clustering of schistosomiasis cases at the village level demonstrated a downward trend from 2013 from 2017 in Hubei Province. High-risk regions included Jianghan Plain along the middle reach of Yangtze River and Yangxin County in the lower reaches of the Yangtze River in Hubei Province. To eliminate schistosomiasis, precise control and management of schistosomiasis cases should be strictly implemented. Moreover, comprehensive prevention and control measures should be continuously strengthened in these regions.
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