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Elguindy DAS, Ashour DS, Elmarhoumy SM, El-Guindy DM, Ismail HIH. The efficacy of cercarial antigen loaded on nanoparticles as a potential vaccine candidate in Schistosoma mansoni-infected mice. J Parasit Dis 2024; 48:381-399. [PMID: 38840868 PMCID: PMC11147980 DOI: 10.1007/s12639-024-01677-z] [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: 02/03/2024] [Accepted: 04/21/2024] [Indexed: 06/07/2024] Open
Abstract
Schistosomiasis is one of the most common causes of morbidity and mortality from parasitic diseases. Mass treatment has proven to be insufficient because of repeated infection after treatment and the appearance of strains resistant to drug therapy. Hence, immunization is a new approach to control the disease and limit the pathological consequences of schistosomiasis. To evaluate the prophylactic effect of Cercarial antigen (CAP) loaded on chitosan nanoparticles (CSNPs) as a potential vaccine against Schistosoma mansoni-infected mice. 130 mice divided into 2 groups were used: Group I: Control groups (50 mice) subdivided into subgroup Ia (10 mice): Non-infected mice (normal control), subgroup Ib (20 mice): Schistosoma infected mice (infected control) and subgroup Ic (20 mice): Non-infected mice receiving NPs only. Group II: Vaccinated group (80 mice) subdivided equally into subgroup IIa (CAP): Received cercarial antigen and subgroup IIb (CAP + CSNP): Received cercarial antigen loaded on chitosan NPs then both vaccinated groups were infected with S. mansoni 3 weeks following the initial vaccination dose. CAP + CSNP and CAP groups showed significant reduction in adult worms count, hepatic egg count, hepatic granulomas number and size in comparison to the infected control group. Elevation of serum IgG and IgM levels, CD4+ and CD8+ T cell frequencies, IL-4, IL-10 and INF-γ levels was more significant in CAP + CSNP group than CAP group. CAP + CSNP is a promising new preparation of Schistosomal antigens that gave better results than immunization with CAP alone. CSNPs enhanced the immune and protective effect of CAP as validated by parasitological, histopathological and immunohistochemical studies.
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Affiliation(s)
- Dina A. S. Elguindy
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Dalia S. Ashour
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Sirria M. Elmarhoumy
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Dina M. El-Guindy
- Pathology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Howaida I. H. Ismail
- Medical Parasitology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
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Jain S, Rana M, Choubey P, Kumar S. Schistosoma japonicum Associated Colorectal Cancer and Its Management. Acta Parasitol 2023; 68:723-734. [PMID: 37594685 DOI: 10.1007/s11686-023-00707-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 07/31/2023] [Indexed: 08/19/2023]
Abstract
BACKGROUND An association between Schistosoma japonicum and colorectal cancer in humans has been known since a long time; however, this association remains understudied and lacks comprehensive experimentation support. OBJECTIVE Various epidemiological and pathological studies have established the role of chronic inflammation as a major factor behind the induction of colorectal cancer. The aim of this review is to present the current knowledge on the association of Schistosoma japonicum with colorectal cancer. RESULT Mechanisms which lead to induction and progression of colorectal cancer are highlighted along with diagnosis and treatment for the same. Further, various methodologies, including mass drug administration, use of new drugs and vaccines, role of apoptosis, and histone-modifying enzymes, have been described which can either prevent the schistosomal infection itself or can check it from reaching an advanced stage. CONCLUSIONS Epidemiological, clinical, pathological and surgical studies suggest that Schistosoma japonicum is responsible for induction of colorectal cancer. However, thorough clinical studies are required to support and globally accept this notion. Further, methodologies highlighted in this work can be employed in order to take care of schistosomal infection or address the cancer induction and progression.
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Affiliation(s)
- Sidhant Jain
- Institute for Globally Distributed Open Research and Education (IGDORE), Rewari, Haryana, India.
| | - Meenakshi Rana
- Dyal Singh College, University of Delhi, Lodhi Road, Pragati Vihaar, New Delhi, 110003, India
| | - Pooja Choubey
- Department of Zoology, Gate No. 3, Chaatra Marg, University of Delhi, North Campus, Delhi, 110007, India
| | - Sahil Kumar
- Department of Pharmacology, ESIC Dental College and Hospital, Rohini, Sector-15, Delhi, 110089, India
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Bundy DAP, Schultz L, Antoninis M, Barry FBM, Burbano C, Croke K, Drake L, Gyapong J, Karutu C, Kihara J, Lo MM, Makkar P, Mwandawiro C, Ossipow SJ, Bento AR, Rollinson D, Shah H, Turner HC. A positive consequence of the COVID-19 pandemic: how the counterfactual experience of school closures is accelerating a multisectoral response to the treatment of neglected tropical diseases. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220282. [PMID: 37598709 PMCID: PMC10440164 DOI: 10.1098/rstb.2022.0282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/07/2023] [Indexed: 08/22/2023] Open
Abstract
Global access to deworming treatment is one of the public health success stories of low-income countries in the twenty-first century. Parasitic worm infections are among the most ubiquitous chronic infections of humans, and early success with mass treatment programmes for these infections was the key catalyst for the neglected tropical disease (NTD) agenda. Since the launch of the 'London Declaration' in 2012, school-based deworming programmes have become the world's largest public health interventions. WHO estimates that by 2020, some 3.3 billion school-based drug treatments had been delivered. The success of this approach was brought to a dramatic halt in April 2020 when schools were closed worldwide in response to the COVID-19 pandemic. These closures immediately excluded 1.5 billion children not only from access to education but also from all school-based health services, including deworming. WHO Pulse surveys in 2021 identified NTD treatment as among the most negatively affected health interventions worldwide, second only to mental health interventions. In reaction, governments created a global Coalition with the twin aims of reopening schools and of rebuilding more resilient school-based health systems. Today, some 86 countries, comprising more than half the world's population, are delivering on this response, and school-based coverage of some key school-based programmes exceeds those from January 2020. This paper explores how science, and a combination of new policy and epidemiological perspectives that began in the 1980s, led to the exceptional growth in school-based NTD programmes after 2012, and are again driving new momentum in response to the COVID-19 pandemic. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Donald A. P. Bundy
- Research Consortium for School Health and Nutrition, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Linda Schultz
- Research Consortium for School Health and Nutrition, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | | | | | | | - Kevin Croke
- Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | | | - John Gyapong
- University of Health and Allied Sciences, PMB 31, Ho, Volta Region, Ghana
| | | | | | | | | | | | | | | | | | | | - Hugo C. Turner
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London SW7 2BX, UK
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Lebu S, Kibone W, Muoghalu CC, Ochaya S, Salzberg A, Bongomin F, Manga M. Soil-transmitted helminths: A critical review of the impact of co-infections and implications for control and elimination. PLoS Negl Trop Dis 2023; 17:e0011496. [PMID: 37561673 PMCID: PMC10414660 DOI: 10.1371/journal.pntd.0011496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023] Open
Abstract
Researchers have raised the possibility that soil-transmitted helminth (STH) infections might modify the host's immune response against other systemic infections. STH infections can alter the immune response towards type 2 immunity that could then affect the likelihood and severity of other illnesses. However, the importance of co-infections is not completely understood, and the impact and direction of their effects vary considerably by infection. This review synthesizes evidence regarding the relevance of STH co-infections, the potential mechanisms that explain their effects, and how they might affect control and elimination efforts. According to the literature reviewed, there are both positive and negative effects associated with STH infections on other diseases such as malaria, human immunodeficiency virus (HIV), tuberculosis, gestational anemia, pediatric anemia, neglected tropical diseases (NTDs) like lymphatic filariasis, onchocerciasis, schistosomiasis, and trachoma, as well as Coronavirus Disease 2019 (COVID-19) and human papillomavirus (HPV). Studies typically describe how STHs can affect the immune system and promote increased susceptibility, survival, and persistence of the infection in the host by causing a TH2-dominated immune response. The co-infection of STH with other diseases has important implications for the development of treatment and control strategies. Eliminating parasites from a human host can be more challenging because the TH2-dominated immune response induced by STH infection can suppress the TH1 immune response required to control other infections, resulting in an increased pathogen load and more severe disease. Preventive chemotherapy and treatment are currently the most common approaches used for the control of STH infections, but these approaches alone may not be adequate to achieve elimination goals. Based on the conclusions drawn from this review, integrated approaches that combine drug administration with water, sanitation and hygiene (WASH) interventions, hygiene education, community engagement, and vaccines are most likely to succeed in interrupting the transmission of STH co-infections. Gaining a better understanding of the behavior and relevance of STH co-infections in the context of elimination efforts is an important intermediate step toward reducing the associated burden of disease.
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Affiliation(s)
- Sarah Lebu
- The Water Institute at UNC, Department of Environmental Sciences and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Winnie Kibone
- School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Chimdi C. Muoghalu
- The Water Institute at UNC, Department of Environmental Sciences and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Stephen Ochaya
- Department of Microbiology and Immunology, Faculty of Medicine, Gulu University, Gulu, Uganda
- Department of Biology, Faculty of Science, Gulu University, Gulu, Uganda
- Department of Clinical Pathology, Uppsala Academic Hospital, Uppsala, Sweden
| | - Aaron Salzberg
- The Water Institute at UNC, Department of Environmental Sciences and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Felix Bongomin
- Department of Microbiology and Immunology, Faculty of Medicine, Gulu University, Gulu, Uganda
| | - Musa Manga
- The Water Institute at UNC, Department of Environmental Sciences and Engineering, Gillings School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
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Aly NSM, Kim HS, Eraky MA, El Kholy AA, Ali BT, Miyoshi SI, Omar RE. Evaluation of schistosomula lung antigen preparation and soluble egg antigen vaccines on experimental schistosomiasis mansoni. PARASITES, HOSTS AND DISEASES 2023; 61:251-262. [PMID: 37648230 PMCID: PMC10471471 DOI: 10.3347/phd.22154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 07/20/2023] [Indexed: 09/01/2023]
Abstract
Schistosomiasis causes significant morbidity and mortality worldwide. This study aimed to assess the effect of schistosomula lung antigen preparation (SLAP) and soluble egg antigen (SEA) on a murine schistosomiasis mansoni model. Ninety laboratory-bred male Swiss albino mice were divided into 6 groups. Two doses of the vaccine were given at 2-week intervals. All mice were subcutaneously infected with 80±10 Schistosoma mansoni cercariae 2 weeks after the last vaccination dose. They were sacrificed 7 weeks post-infection. Parasitological and histopathological studies were conducted to assess the effect of inoculated antigens (single or combined). The results showed that the combination of SLAP and SEA (combination group) led to a significant reduction in worm burden (65.56%), and liver and intestine egg count (59% and 60.59%, respectively). The oogram pattern revealed a reduction in immature and mature eggs (15±0.4 and 10±0.8, respectively) and an increased number of dead eggs in the combination group (P<0.001). In terms of histopathological changes, the combination group showed notably small compact fibrocellular egg granuloma and moderate fibrosis in the liver. A high percentage of destroyed ova was observed in the intestine of the combination group. This study demonstrates for the first time the prophylactic effect of combined SLAP and SEA vaccine. The vaccine induced a significant reduction in the parasitological and pathological impacts of schistosomiasis mansoni in hepatic and intestinal tissues, making it a promising vaccine candidate for controlling schistosomiasis.
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Affiliation(s)
- Nagwa S. M. Aly
- Department of Parasitology, Benha Faculty of Medicine, Benha University,
Egypt
- Division of International Infectious Diseases Control, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Hye-Sook Kim
- Division of International Infectious Diseases Control, Faculty of Pharmaceutical Sciences, Okayama University, Tsushima-Naka, Kita-Ku, Okayama 700-8530,
Japan
| | - Maysa A. Eraky
- Department of Parasitology, Benha Faculty of Medicine, Benha University,
Egypt
| | - Asmaa A. El Kholy
- Department of Parasitology, Benha Faculty of Medicine, Benha University,
Egypt
| | - Basma T. Ali
- Department of Parasitology, Benha Faculty of Medicine, Benha University,
Egypt
| | - Shin-ichi Miyoshi
- Department of Sanitary Microbiology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530,
Japan
| | - Rabab E. Omar
- Department of Parasitology, Benha Faculty of Medicine, Benha University,
Egypt
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Torres-Vitolas CA, Trienekens SCM, Zaadnoordijk W, Gouvras AN. Behaviour change interventions for the control and elimination of schistosomiasis: A systematic review of evidence from low- and middle-income countries. PLoS Negl Trop Dis 2023; 17:e0011315. [PMID: 37163556 DOI: 10.1371/journal.pntd.0011315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 05/22/2023] [Accepted: 04/16/2023] [Indexed: 05/12/2023] Open
Abstract
BACKGROUND For the last two decades, schistosomiasis control efforts have focussed on preventive treatment. The disease, however, still affects over 200 million people worldwide. Behaviour change (BC) interventions can strengthen control by interrupting transmission through modifying exposure behaviour (water contact) or transmission practices (open urination/defaecation); or through fostering treatment seeking or acceptance. This review examines these interventions to assess their effectiveness in modifying risk practices and affecting epidemiological trends. METHODOLOGY/PRINCIPAL FINDINGS A systematic multi-database literature search (PROSPERO CRD42021252368) was conducted for peer-reviewed publications released at any time before June 2021 assessing BC interventions for schistosomiasis control in low- and middle-income countries. 2,593 unique abstracts were identified, 66 were assigned to full text review, and 32 met all inclusion criteria. A typology of intervention models was outlined according to their use of behaviour change techniques and overarching rationale: health education (HEIs), social-environmental (SEIs), physical-environmental (PEIs), and incentives-centred interventions (ICIs). Available evidence does not allow to identify which BC approach is most effective in controlling risk behaviour to prevent schistosomiasis transmission. HEIs' impacts were observed to be limited by structural considerations, like infrastructure underdevelopment, economic obligations, socio-cultural traditions, and the natural environment. SEIs may address those challenges through participatory planning and implementation activities, which enable social structures, like governance and norms, to support BC. Their effects, however, appear context-sensitive. The importance of infrastructure investments was highlighted by intervention models. To adequately support BC, however, they require users' inputs and complementary services. Whilst ICIs reported positive impacts on treatment uptake, there are cost-effectiveness and sustainability concerns. Evaluation studies yielded limited evidence of independent epidemiological impacts from BC, due to limited use of suitable indicators and comparators. There was indicative evidence, however, that BC projects could sustain gains through treatment campaigns. CONCLUSIONS/SIGNIFICANCE There is a need for integrated interventions combining information provision, community-based planning, and infrastructure investments to support BC for schistosomiasis control. Programmes should carefully assess local conditions before implementation and consider that long-term support is likely needed. Available evidence indicates that BC interventions may contribute towards schistosomiasis control when accompanied by treatment activities. Further methodologically robust evidence is needed to ascertain the direct epidemiological benefits of BC.
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Affiliation(s)
- Carlos A Torres-Vitolas
- Unlimit Health, London, United Kingdom
- School of Public Health, Imperial College London, London, United Kingdom
| | - Suzan C M Trienekens
- School of Biodiversity, One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Masaku J, Okoyo C, Araka S, Musuva R, Njambi E, Njomo DW, Mwandawiro C, Njenga SM. Understanding factors responsible for the slow decline of soil-transmitted helminthiasis following seven rounds of annual mass drug administration (2012-2018) among school children in endemic counties of Kenya: A mixed method study. PLoS Negl Trop Dis 2023; 17:e0011310. [PMID: 37141340 DOI: 10.1371/journal.pntd.0011310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 05/16/2023] [Accepted: 04/13/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Soil-transmitted helminthiasis (STH) continue to be a significant health problem in Sub-Saharan Africa especially among school children. In Kenya, treatment of over five million children has been conducted annually in 28 endemic counties since the year 2012. However, the latest monitoring and evaluation (M&E) results indicated a slow decline of prevalence and intensity of STH in some counties after the seven rounds of annual mass drug administration (MDA). The current study sought to determine the factors associated with the slow decline in prevalence and intensity of STH among school children participating in the school deworming programme. METHODOLOGY Mixed methods cross-sectional study was conducted in three endemic counties of Kenya. For quantitative technique, simple random sampling was used to select 1,874 school children from six purposively selected primary schools. The school children were interviewed, and a single stool collected and analysed using Kato-Katz technique. While for qualitative methods, 15 focus group discussions (FGDs) were conducted with purposively selected parents/guardians of school children. Data was collected through voice records using FGD and analyzed using NVIVO. FINDINGS Prevalence of any STH infection was 30.8% (95%CI: 28.7-32.9), with the highest prevalence observed in Vihiga County (40.7%; 95%CI: 37.4-44.4). Multivariable analysis revealed that geographical location (OR = 3.78, (95%CI: 1.81-7.88) p<0.001), and not washing hands after defecation (OR = 1.91, (95%CI: 1.13-3.20) p = 0.015) were significantly associated with any STH infection. For qualitative analysis, majority of the parents/guardians of SAC felt that poor water sanitation and hygiene practices (WASH) both in school and household level could be a cause of continued STH infection. Also failing to include the rest of the community members in the MDAs were mentioned as possible contributors to observed slow decline of STH. CONCLUSIONS There was moderate STH prevalence and mean intensity despite the seven rounds of repeated annual MDA. The study recommends a revamped awareness creation on WASH and community wide treatment.
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Affiliation(s)
- Janet Masaku
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Collins Okoyo
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Sylvie Araka
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Rosemary Musuva
- Centre for Global Health Research (CGHR) Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Elizabeth Njambi
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Doris W Njomo
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Charles Mwandawiro
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
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Anisuzzaman, Hossain MS, Hatta T, Labony SS, Kwofie KD, Kawada H, Tsuji N, Alim MA. Food- and vector-borne parasitic zoonoses: Global burden and impacts. ADVANCES IN PARASITOLOGY 2023; 120:87-136. [PMID: 36948728 DOI: 10.1016/bs.apar.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Around 25% of the global population suffer from one or more parasitic infections, of which food- and vector-borne parasitic zoonotic diseases are a major concern. Additionally, zoonoses and communicable diseases, common to man and animals, are drawing increased attention worldwide. Significant changes in climatic conditions, cropping pattern, demography, food habits, increasing international travel, marketing and trade, deforestation, and urbanization play vital roles in the emergence and re-emergence of parasitic zoonoses. Although it is likely to be underestimated, the collective burden of food- and vector-borne parasitic diseases accounts for ∼60 million disability-adjusted life years (DALYs). Out of 20 neglected tropical diseases (NTDs) listed by the World Health Organization (WHO) and the Centres for Disease Control and Prevention (CDC), 13 diseases are of parasitic origin. There are about 200 zoonotic diseases of which the WHO listed eight as neglected zoonotic diseases (NZDs) in the year 2013. Out of these eight NZDs, four diseases, namely cysticercosis, hydatidosis, leishmaniasis, and trypanosomiasis, are caused by parasites. In this review, we discuss the global burden and impacts of food- and vector-borne zoonotic parasitic diseases.
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Affiliation(s)
- Anisuzzaman
- Department of Parasitology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh.
| | - Md Shahadat Hossain
- Department of Parasitology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Takeshi Hatta
- Department of Parasitology and Tropical Medicine, Kitasato University School of Medicine, Minami, Sagamihara, Kanagawa, Japan
| | - Sharmin Shahid Labony
- Department of Parasitology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh
| | - Kofi Dadzie Kwofie
- Department of Parasitology and Tropical Medicine, Kitasato University School of Medicine, Minami, Sagamihara, Kanagawa, Japan; Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Hayato Kawada
- Department of Parasitology and Tropical Medicine, Kitasato University School of Medicine, Minami, Sagamihara, Kanagawa, Japan
| | - Naotoshi Tsuji
- Department of Parasitology and Tropical Medicine, Kitasato University School of Medicine, Minami, Sagamihara, Kanagawa, Japan.
| | - Md Abdul Alim
- Department of Parasitology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh
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Detection of Schistosoma mekongi DNA in Human Stool and Intermediate Host Snail Neotricula aperta via Loop-Mediated Isothermal Amplification Assay in Lao PDR. Pathogens 2022; 11:pathogens11121413. [PMID: 36558747 PMCID: PMC9785648 DOI: 10.3390/pathogens11121413] [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: 10/25/2022] [Revised: 11/09/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Schistosomiasis mekongi infection represents a public health concern in Laos and Cambodia. While both countries have made significant progress in disease control over the past few decades, eradication has not yet been achieved. Recently, several studies reported the application of loop-mediated isothermal amplification (LAMP) for detecting Schistosoma DNA in low-transmission settings. The objective of this study was to develop a LAMP assay for Schistosoma mekongi using a simple DNA extraction method. In particular, we evaluated the utility of the LAMP assay for detecting S. mekongi DNA in human stool and snail samples in endemic areas in Laos. We then used the LAMP assay results to develop a risk map for monitoring schistosomiasis mekongi and preventing epidemics. A total of 272 stool samples were collected from villagers on Khon Island in the southern part of Laos in 2016. DNA for LAMP assays was extracted via the hot-alkaline method. Following the Kato-Katz method, we determined that 0.4% (1/272) of the stool samples were positive for S. mekongi eggs, as opposed to 2.9% (8/272) for S. mekongi DNA based on the LAMP assays. Snail samples (n = 11,762) were annually collected along the riverside of Khon Island from 2016 to 2018. DNA was extracted from pooled snails as per the hot-alkaline method. The LAMP assay indicated that the prevalence of S. mekongi in snails was 0.26% in 2016, 0.08% in 2017, and less than 0.03% in 2018. Based on the LAMP assay results, a risk map for schistosomiasis with kernel density estimation was created, and the distribution of positive individuals and snails was consistent. In a subsequent survey of residents, schistosomiasis prevalence among villagers with latrines at home was lower than that among villagers without latrines. This is the first study to develop and evaluate a LAMP assay for S. mekongi detection in stools and snails. Our findings indicate that the LAMP assay is an effective method for monitoring pathogen prevalence and creating risk maps for schistosomiasis.
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Ihnacik L, Šmigová J, Šoltys J, Bobíková D, Kuzevičová Ž, Kuzevič Š, Schusterová I, Papajová I. The survey of soil-transmitted helminth species abundance in Slovakia with an emphasis on parameters important for their distribution. Front Med (Lausanne) 2022; 9:1043313. [PMID: 36465912 PMCID: PMC9712972 DOI: 10.3389/fmed.2022.1043313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/03/2022] [Indexed: 01/03/2024] Open
Abstract
Soil-transmitted helminths (STH) can be easily dispensable in socially disadvantaged groups. The Roma people represent the group most at risk in Slovakia. This study aimed to investigate the occurrence of STH infections in minorities living with animals under low hygienic conditions and on contaminated soil. Subsequently, we identified the risk assessment factors of the STH transmissions based on parasitological results. In our study, STHs were predominantly found among the Roma communities living in unsanitary conditions. The prevalence of Ascaris lumbricoides among the majority was 0.79%, and Trichuris trichiura was 0.05 %. On the contrary, a community-based cross-sectional survey across eastern Slovakia also found a prevalence of 22.28 and 3.47% for A. lumbricoides and T. trichiura among the Roma population. Inhabitants that belong to the Roma minority had a 37.12 infection OR times higher than non-Roma inhabitants. The Roma people living in the countryside have a 2.23-fold higher chance of getting infected with STH than Roma living in the city. Therefore, soil and domestic animals were also examined for the presence of the STH eggs to show the environmental burden. In general, the presence of STH eggs was confirmed in 26.26% of the soil examined samples. The detailed description is as follows: eggs of Toxocara spp., Trichuris spp., eggs from the family Ancylostomatidae, and Toxascaris leonina. Ascaris eggs were detected only in the soil from localities with low hygienic standards. The probability of contracting the STH eggs in segregated settlements was 15.94 times higher compared to urban or rural areas. In addition to humans, dogs can also be a source of STH eggs in the soil. The STH eggs were confirmed in 43.55% of dog droppings. The most interesting finding was that the eggs of the genus Ascaris were up to 7.93% of dog droppings from localities with a low hygienic standard were positive. This study revealed that climatic factors and the WASH conditions influenced the distribution of STHs to variable degrees. In addition, ethnicity and sanitation were crucial factors in the distribution of STH infection in eastern Slovakia.
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Affiliation(s)
- Lukáš Ihnacik
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovakia
- Department of Public Veterinary Medicine and Animal Welfare, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovakia
| | - Júlia Šmigová
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovakia
| | - Jindřich Šoltys
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovakia
| | - Diana Bobíková
- Faculty of Mining, Ecology, Process Control, and Geotechnologies, Technical University of Košice, Košice, Slovakia
| | - Žofia Kuzevičová
- Faculty of Mining, Ecology, Process Control, and Geotechnologies, Technical University of Košice, Košice, Slovakia
| | - Štefan Kuzevič
- Faculty of Mining, Ecology, Process Control, and Geotechnologies, Technical University of Košice, Košice, Slovakia
| | - Ingrid Schusterová
- Faculty of Medicine, East Slovak Institute of Cardiovascular Diseases, Košice, Slovakia
| | - Ingrid Papajová
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovakia
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Phillips AE, Ower AK, Mekete K, Liyew EF, Maddren R, Belay H, Chernet M, Anjulo U, Mengistu B, Salasibew M, Tasew G, Anderson R. Association between water, sanitation, and hygiene access and the prevalence of soil-transmitted helminth and schistosome infections in Wolayita, Ethiopia. Parasit Vectors 2022; 15:410. [DOI: 10.1186/s13071-022-05465-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 09/03/2022] [Indexed: 11/06/2022] Open
Abstract
Abstract
Background
The Geshiyaro project is a 5-year intervention to assess the impact of community- and school-based water, sanitation, and hygiene (WaSH) interventions on reducing infection with soil-transmitted helminths (STH) and schistosome parasites in combination with deworming in Wolayita zone, Ethiopia.
Methods
A population-based, cross-sectional census and parasitological mapping activity was conducted between 2018 and 2019. Individuals in the census were identified using either a registered study ID card or biometric fingerprint to enable linkage of their household WaSH data with baseline STH and schistosome prevalence for risk analysis.
Results
Prevalence of STH was 15.5% for any STH species, 9.47% for Ascaris lumbricoides, 1.78% for Trichuris trichiura, and 7.24% for hookworm. Intestinal schistosomiasis (Schistosoma mansoni) infection prevalence was 0.85% by Kato Katz, 21.6% by POC-CCA trace positive (Tr +), and 13.3% trace negative (Tr-). Microhaematuria was 2.77%, with 0.13% of people examined with S. haematobium eggs detected by urine filtration. At the household level, increased (> 30 min) time taken to collect drinking water, sharing a latrine, and lack of handwashing facilities were all associated with a greater risk of A. lumbricoides, hookworm, and S. mansoni infection. Not disposing of infant stool at the household and clothes washing/recreational freshwater contact were significantly associated with higher risk of schistosomiasis infection. Aggregating WaSH data at the community level showed odds of A. lumbricoides, hookworm, and T. trichiura infection were significantly lower as both community sanitation coverage and access to improved drinking water improved.
Conclusions
The principal finding of this study is that lack of access to WaSH, such as improved drinking water and shared toilet and hand-washing facilities, were linked to an increased risk of infection with STH and schistosome parasites. These associations are difficult to establish at an individual household level because of wide variability in access between houses but are detectable when coverage is aggregated at the community level. Maintenance of WaSH facilities as well as increased access within the whole community is important in influencing the community-wide prevalence of infection with STH and schistosome parasites.
Graphical Abstract
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12
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Karutu C, Schultz L, Waltz J, Campbell SJ, Kamara K, Yotebieng K, Gouvras A, Rollinson D, Bundy DAP. A coordinated response to the needs of the learner: How deworming and school meals together will contribute to the global recovery from the COVID-19 pandemic. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.998276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Webb AJ, Allan F, Kelwick RJR, Beshah FZ, Kinung’hi SM, Templeton MR, Emery AM, Freemont PS. Specific Nucleic AcId Ligation for the detection of Schistosomes: SNAILS. PLoS Negl Trop Dis 2022; 16:e0010632. [PMID: 35881651 PMCID: PMC9355235 DOI: 10.1371/journal.pntd.0010632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 08/05/2022] [Accepted: 07/04/2022] [Indexed: 11/18/2022] Open
Abstract
Schistosomiasis, also known as bilharzia or snail fever, is a debilitating neglected tropical disease (NTD), caused by parasitic trematode flatworms of the genus Schistosoma, that has an annual mortality rate of 280,000 people in sub-Saharan Africa alone. Schistosomiasis is transmitted via contact with water bodies that are home to the intermediate host snail which shed the infective cercariae into the water. Schistosome lifecycles are complex, and while not all schistosome species cause human disease, endemic regions also typically feature animal-infecting schistosomes that can have broader economic and/or food security implications. Therefore, the development of species-specific Schistosoma detection technologies may help to inform evidence-based local environmental, food security and health systems policy making. Crucially, schistosomiasis disproportionally affects low- and middle-income (LMIC) countries and for that reason, environmental screening of water bodies for schistosomes may aid with the targeting of water, sanitation, and hygiene (WASH) interventions and preventive chemotherapy to regions at highest risk of schistosomiasis transmission, and to monitor the effectiveness of such interventions at reducing the risk over time. To this end, we developed a DNA-based biosensor termed Specific Nucleic AcId Ligation for the detection of Schistosomes or ‘SNAILS’. Here we show that ‘SNAILS’ enables species-specific detection from genomic DNA (gDNA) samples that were collected from the field in endemic areas. Schistosomiasis is a neglected tropical disease, caused by the parasitic trematodes of the genus Schistosoma. Schistosomiasis is endemic to regions within Africa, Asia and South America with at least 250 million people infected and a further 779 million at risk of infection. The lifecycle of schistosomes are complex and involve specific freshwater intermediate snail hosts which shed infective cercariae into the waterbodies they inhabit. Schistosomiasis is subsequently transmitted to humans or animals that contact cercariae contaminated water. In Africa, human disease is largely caused by Schistosoma mansoni and Schistosoma haematobium. However, endemic regions also typically feature animal-infecting schistosomes that can have broader economic and/or food security implications. Therefore, the development of species-specific Schistosoma detection technologies may help to inform local environmental, food security and health programmes. To this end, we re-purposed a nucleic acid detection technology to enable the detection of different schistosome species. Our DNA-biosensor, abbreviated as ‘SNAILS’, employs carefully designed probes that recognise species-specific DNA sequences, coupled with enzymatic amplification steps, and a fluorescent signal-dye to indicate a positive detection. ‘SNAILS’ successfully differentiates between S. mansoni and S. haematobium samples and could conceivably be employed within future global health programmes.
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Affiliation(s)
- Alexander James Webb
- Section of Structural and Synthetic biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Fiona Allan
- Department of Life Sciences, Natural History Museum, London, United Kingdom
| | - Richard J. R. Kelwick
- Section of Structural and Synthetic biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Feleke Zewge Beshah
- College of Natural and Computational Sciences, Addis Ababa University, Arat Kilo, Addis Ababa, Ethiopia
| | | | - Michael R. Templeton
- Department of Civil and Environmental Engineering, Imperial College London, London, United Kingdom
| | - Aidan Mark Emery
- Department of Life Sciences, Natural History Museum, London, United Kingdom
- * E-mail: (AME); (PSF)
| | - Paul S. Freemont
- Section of Structural and Synthetic biology, Department of Infectious Disease, Imperial College London, London, United Kingdom
- The London Biofoundry, Imperial College Translation and Innovation Hub, White City Campus, London, United Kingdom
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London, Hammersmith Campus, London, United Kingdom
- * E-mail: (AME); (PSF)
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Clark J, Moses A, Nankasi A, Faust CL, Moses A, Ajambo D, Besigye F, Atuhaire A, Wamboko A, Carruthers LV, Francoeur R, Tukahebwa EM, Prada JM, Lamberton PHL. Reconciling Egg- and Antigen-Based Estimates of Schistosoma mansoni Clearance and Reinfection: A Modeling Study. Clin Infect Dis 2022; 74:1557-1563. [PMID: 34358299 PMCID: PMC9070857 DOI: 10.1093/cid/ciab679] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, affected treatment efficacy and reinfection rate estimates. The point-of-care circulating cathodic antigen (referred to from here as POC-CCA+) test is advocated as an improvement on the Kato-Katz method, but improved estimates are limited by ambiguities in the interpretation of trace results. METHOD We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer's guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations. RESULTS Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks. CONCLUSIONS Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
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Affiliation(s)
- Jessica Clark
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | | | - Christina L Faust
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Adriko Moses
- Vector Control Division, Ministry of Health, Uganda
| | - Diana Ajambo
- Vector Control Division, Ministry of Health, Uganda
| | - Fred Besigye
- Vector Control Division, Ministry of Health, Uganda
| | | | | | - Lauren V Carruthers
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Rachel Francoeur
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Faculty of Science & Engineering, University of Chester, Chester, United Kingdom
| | | | - Joaquin M Prada
- Faculty of Health & Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Poppy H L Lamberton
- Wellcome Centre for Integrative Parasitology, Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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Jeza VT, Mutuku F, Kaduka L, Mwandawiro C, Masaku J, Okoyo C, Kanyi H, Kamau J, Ng'ang'a Z, Kihara JH. Schistosomiasis, soil transmitted helminthiasis, and malaria co-infections among women of reproductive age in rural communities of Kwale County, coastal Kenya. BMC Public Health 2022; 22:136. [PMID: 35045848 PMCID: PMC8772099 DOI: 10.1186/s12889-022-12526-0] [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: 04/05/2021] [Accepted: 01/06/2022] [Indexed: 11/10/2022] Open
Abstract
Background Schistosoma haematobium, soil transmitted helminthes (STH), and malaria lead to a double burden in pregnancy that eventually leads to poor immunity, increased susceptibility to other infections, and poor pregnancy outcomes. Many studies have been carried out on pre-school and school aged children but very little has been done among the at risk adult population including women of reproductive age (WRA). Our current study sought to establish the risk factors and burden of co-infection with S. haematobium, STH, and Plasmodium sp. among WRA in Kwale County, Coastal Kenya. Methods A total of 534 WRA between the ages of 15–50 were enrolled in this cross-sectional study from four villages; Bilashaka and Mwaluphamba in Matuga sub-County, and Mwachinga and Dumbule in Kinango sub-County. Socio-demographic information was collected using a pre-tested standardized questionnaire. Parasitological examination was done using urine filtration method for Schistosoma haematobium, Kato Katz for STH (Ascaris lumbricoides, Hookworm, Trichuris trichiura), and standard slide microscopy for Plasmodium sp. Statistical analyses were carried out using STATA version 15.1. Results The overall prevalence of S. haematobium was 3.8% (95% CI: 2.6–5.4) while that for malaria was 4.9% (95% CI: 2.0–11.7). The prevalence of STH was 5.6% (95% CI: 2.8–11.3) with overall prevalence of 5.3% (95% CI: 2.5–10.9) for hookworm and 0.6% (95% CI: 0.2–1.9) for T. trichiura. The occurrence of co-infection was low and was recorded between S. haematobium and P. falciparum (0.6%), followed by S. haematobium and STH (0.4%). Among pregnant women, 2.6% had co-infection with S. haematobium and P. falciparum. Only 1.3% had co-infection with S. haematobium and hookworm or T. trichiura. Among non-pregnant women, co-infection with S. haematobium and P. falciparum was 0.2%. Similarly, co-infection with S. haematobium and hookworm or T. trichiura was 0.2%. Bed net ownership and usage among pregnant women was 87.8 and 96.6%, respectively. 66.3% of the women reported using improved water sources for drinking while 78.1% reported using improved sanitation facilities. Conclusion The use of improved WASH activities might have contributed to the low prevalence of STHs and S. haematobium infections. Further, bed net ownership and usage might have resulted in the low prevalence of Plasmodium sp. infections observed. Supplementary Information The online version contains supplementary material available at 10.1186/s12889-022-12526-0.
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Affiliation(s)
- Victor Tunje Jeza
- Department of Medical Sciences, Technical University of Mombasa, Mombasa, Kenya.
| | - Francis Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Lydia Kaduka
- Center for Publich Health Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Charles Mwandawiro
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Janet Masaku
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Collins Okoyo
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Henry Kanyi
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Joyce Kamau
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Zipporah Ng'ang'a
- Office of the Deputy Vice Chancellor, South Eastern Kenya University, Kitui, Kenya
| | - Jimmy Hussein Kihara
- Eastern and Southern Africa Center for International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
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Olkeba BK, Boets P, Mereta ST, Mandefro B, Debesa G, Ahmednur M, Ambelu A, Korma W, Goethals PLM. Malacological and Parasitological Surveys on Ethiopian Rift Valley Lakes: Implications for Control and Elimination of Snail-Borne Diseases. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 19:ijerph19010142. [PMID: 35010399 PMCID: PMC8750326 DOI: 10.3390/ijerph19010142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 05/28/2023]
Abstract
Schistosomiasis is one of the snail-borne diseases responsible for the second-highest burden of diseases among neglected tropical diseases. The use of mass drug administration to the populations most at risk is a backbone of the strategy to prevent and control schistosomiasis transmission. However, it offers no protection against re-infection, and humans are often re-exposed when they return to water bodies where snails release cercariae. Surveys on cercarial infection in snails could provide better insights on human disease risk. Hence, in this study, we investigated cercarial infection in snails and also determined the epidemiology of Schistosoma mansoni among fishermen at Ethiopian Rift Valley lakes. Freshwater snails were collected from the shorelines of Ethiopian Rift Valley lakes for examination of cercarial infection during 2020. Environmental data on water quality variables and physical characteristics of snail habitats were collected. Stool samples were collected from fishermen and the Kato-Katz technique was applied for the quantification of Schistosoma mansoni eggs. A malacological survey indicated that six morphologically distinguishable types of cercariae were found in snails. Infected snails with cercaria were more likely present in habitats with high five-day biological oxygen demand and low dissolved oxygen. The overall prevalence of Schistosoma mansoni infection among the fishermen at Ethiopian Rift Valley lakes was found to be 21.5%. This indicates that fishermen at Ethiopian Rift Valley lakes are one of the groups of people harboring schistosome cercariae which are potentially responsible for the transmission of schistosomiasis to lakeshore communities who have contact with lake water. Therefore, complementary medical treatment, public health interventions, environmental management and snail reduction are needed to control the transmission of schistosomiasis.
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Affiliation(s)
- Beekam Kebede Olkeba
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
- Department of Environmental Health Science, Hawassa University, Hawassa 1560, Ethiopia
| | - Pieter Boets
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
- Provincial Centre of Environmental Research, Godshuizenlaan 95, 9000 Ghent, Belgium
| | - Seid Tiku Mereta
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Belayhun Mandefro
- Department of Biology, College of Natural and Computational Sciences, Dilla University, Dilla 419, Ethiopia;
| | - Gemechu Debesa
- Department of Geography and Environmental Studies, Jimma University, Jimma 378, Ethiopia;
| | - Mahmud Ahmednur
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Argaw Ambelu
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Wolyu Korma
- Department of Environmental Health Science and Technology, Jimma University, Jimma 378, Ethiopia; (S.T.M.); (M.A.); (A.A.); (W.K.)
| | - Peter L. M. Goethals
- Department of Animal Sciences and Aquatic Ecology, Ghent University, Coupure Links 653, Building F, 9000 Ghent, Belgium; (P.B.); (P.L.M.G.)
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Schistosoma mansoni infection risk for school-aged children clusters within households and is modified by distance to freshwater bodies. PLoS One 2021; 16:e0258915. [PMID: 34735487 PMCID: PMC8568121 DOI: 10.1371/journal.pone.0258915] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/07/2021] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND The interaction of socio-demographic and ecological factors with Schistosoma mansoni (S. mansoni) infection risk by age and the household clustering of infections between individuals are poorly understood. METHODS This study examined 1,832 individuals aged 5-90 years across 916 households in Mayuge District, Uganda. S. mansoni infection status and intensity were measured using Kato-Katz microscopy. Socio-demographic and ecological factors were examined as predictors of infection status and intensity using logistic and negative binomial regression models, respectively, with standard errors clustered by household. A subgroup analysis of children was conducted to examine the correlation of infection status between children and their caretakers. FINDINGS Infection varied within age groups based on the distance to Lake Victoria. Children aged 9-17 years and young adults aged 18-29 years who lived ≤0.50km from Lake Victoria were more likely to be infected compared to individuals of the same age who lived further away from the lake. Infections clustered within households. Children whose caretakers were heavily infected were 2.67 times more likely to be infected. CONCLUSION These findings demonstrate the focality of schistosome transmission and its dependence on socio-demographic, ecological and household factors. Future research should investigate the sampling of households within communities as a means of progressing towards precision mapping of S. mansoni infections.
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Evaluating the feasibility and acceptability of a community dialogue intervention in the prevention and control of schistosomiasis in Nampula province, Mozambique. PLoS One 2021; 16:e0255647. [PMID: 34351982 PMCID: PMC8341517 DOI: 10.1371/journal.pone.0255647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 07/21/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis is a parasitic neglected tropical disease that ranks second only to malaria in terms of human suffering in the tropics and subtropics. Biomedical disease control interventions need to be complemented with effective prevention and health education strategies, that address the social and environmental determinants of disease. Malaria Consortium conducted an implementation research study between May 2014 and February 2016, in four districts of Nampula province, Mozambique, to test a Community Dialogue (CD) intervention to enhance schistosomiasis prevention and control. The study aimed to evaluate the acceptability and feasibility of using CD to improve communities' level of knowledge, attitudes and practices, and engagement in wider schistosomiasis prevention and control efforts. METHODS The feasibility and acceptability of the CD intervention was evaluated using qualitative and process evaluation data collected throughout the development and implementation phases. Qualitative data sets included key informant interviews (N = 4) with health system personnel, focus group discussions (N = 22) with Community Dialogue facilitators and participants, field observation visits (N = 11), training reports (N = 7), feedback meeting reports (N = 5), CD monitoring sheets (N = 1,458) and CD planning sheets (N = 152). FINDINGS The CD intervention was found highly acceptable and feasible, particularly well-suited to resource poor settings. Non-specialist community volunteers were able to deliver participatory CDs which resulted in increased knowledge among participants and triggered individual and communal actions for improved disease prevention and control. The visual flipchart was a key aid for learning; the use of participatory communication techniques allowed the correction of misconceptions and positioned correct prevention and control practices as the community recommendations, through consensus building. CONCLUSION The Community Dialogue Approach should be embedded within neglected tropical disease control programmes and the health system to create long-lasting synergies between the community and health system for increased effectiveness. However, for behavioural change to be feasible, community engagement strategies need to be supported by improved access to treatment services, safer water and sanitation.
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Keller L, Welsche S, Patel C, Sayasone S, Ali SM, Ame SM, Hattendorf J, Hürlimann E, Keiser J. Long-term outcomes of ivermectin-albendazole versus albendazole alone against soil-transmitted helminths: Results from randomized controlled trials in Lao PDR and Pemba Island, Tanzania. PLoS Negl Trop Dis 2021; 15:e0009561. [PMID: 34191812 PMCID: PMC8277064 DOI: 10.1371/journal.pntd.0009561] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/13/2021] [Accepted: 06/14/2021] [Indexed: 12/13/2022] Open
Abstract
Background Preventive chemotherapy is the cornerstone of soil-transmitted helminth (STH) control. Long-term outcomes and adequate treatment frequency of the recently recommended albendazole-ivermectin have not been studied to date. Methodology/principal findings Double-blind randomized controlled trials were conducted in Lao PDR, Pemba Island, Tanzania and Côte d’Ivoire between 2018 and 2020 to evaluate the efficacy and safety of ivermectin-albendazole versus albendazole-placebo in Trichuris trichiura-infected individuals aged 6 to 60. In the framework of this study, in Lao PDR 466 and 413 participants and on Pemba Island, 558 and 515 participants were followed-up six and 12 months post-treatment, respectively. From each participant at least one stool sample was processed for Kato-Katz diagnosis and cure rates (CRs), egg reduction rates (ERRs) and apparent reinfection rates were calculated. If found helminth-positive at six months, participants were re-treated according to their allocated treatment. Long-term outcomes against T. trichiura based on CRs and ERRs of ivermectin-albendazole compared to albendazole were significantly higher at six months in Lao PDR (CR, 65.8 vs 13.4%, difference; 52.4; 95% CI 45.0–60.0; ERRs, 99.0 vs 79.6, difference 19.4; 95% CI 14.4–24.4) and Pemba Island (CR, 17.8 vs 1.4%, difference; 16.4; 95% CI 11.6–21.0; ERRs, 84.9 vs 21.2, difference 63.8; 95% CI 50.6–76.9) and also at 12 months in Lao PDR (CR, 74.0 vs 23.4%, difference; 50.6; 95% CI 42.6–61.0; ERRs, 99.6 vs 91.3, difference 8.3; 95% CI 5.7–10.8) and Pemba Island (CR, 19.5 vs 3.4%, difference; 16.1; 95% CI 10.7–21.5; ERRs, 92.9 vs 53.6, difference 39.3; 95% CI 31.2–47.4) respectively. Apparent reinfection rates with T. trichiura were considerably higher on Pemba Island (100.0%, 95% CI, 29.2–100.0) than in Lao PDR (10.0%, 95% CI, 0.2–44.5) at 12 months post-treatment for participants treated with albendazole alone. Conclusions/significance The long-term outcomes against T. trichiura of ivermectin-albendazole are superior to albendazole in terms of CRs and ERRs and in reducing infection intensities. Our results will help to guide decisions on how to best use ivermectin-albendazole in the context of large-scale PC programs tailored to the local context to sustainably control STH infections. Trial registration ClinicalTrials.gov registered with clinicaltrials.gov, reference: NCT03527732, date assigned: 17 May 2018. Around 1.5 billion people are infected with the gastrointestinal dwelling nematodes, the so-called soil-transmitted helminths (STHs). Especially chronic high-intensity infections with these parasites can cause substantial morbidity in endemic regions. Preventive chemotherapy, which is the regular administration of a single dose of an anthelmintic drug to at-risk populations, aims to reduce morbidity by lowering the prevalence and intensity of STH infections. Due to the suboptimal efficacy of these recommended single dose monotherapies, particularly against Trichuris trichiura, the use of drug combinations with dissimilar modes of action may enhance treatment efficacy. In double-blind randomized controlled trials in Lao PDR and on Pemba Island, Tanzania, we examined the long-term outcomes of ivermectin-albendazole versus albendazole alone, against T. trichiura. We assessed the infection status, apparent reinfections, new infections and the change of infection intensity for the three major STH species six and 12 months post-treatment. The long-term outcomes (in terms of cure and egg-reduction rates) of the ivermectin-albendazole combination therapy against T. trichiura were significantly higher than that of albendazole alone at all-time points and in both countries. Bi-annual treatment intervals using the ivermectin-albendazole combination might be necessary to sustainably decrease transmission of STH infections.
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Affiliation(s)
- Ladina Keller
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Sophie Welsche
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Chandni Patel
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Somphou Sayasone
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Department of International Program for Health in the Tropics, Lao Tropical and Public Health Institute, Vientiane, Lao People’s Democratic Republic
| | - Said M. Ali
- Public Health Laboratory Ivo de Carneri, Chake Chake, Pemba, Zanzibar, Tanzania
| | - Shaali M. Ame
- Public Health Laboratory Ivo de Carneri, Chake Chake, Pemba, Zanzibar, Tanzania
| | - Jan Hattendorf
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Eveline Hürlimann
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jennifer Keiser
- Medical Parasitology and Infection Biology, Helminth Drug Development Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Mather W, Hutchings P, Budge S, Jeffrey P. Association between water and sanitation service levels and soil-transmitted helminth infection risk factors: a cross-sectional study in rural Rwanda. Trans R Soc Trop Med Hyg 2021; 114:332-338. [PMID: 32052038 DOI: 10.1093/trstmh/trz119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/25/2019] [Accepted: 10/30/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Soil-transmitted helminth (STH) infections are one of the most prevalent neglected tropical diseases in the world. Drug treatment is the preferred method for infection control yet reinfection occurs rapidly, so water and sanitation represent important complementary barriers to transmission. METHODS A cross-sectional study was conducted to observe STH risk factors in rural Rwandan households in relation to the Sustainable Development Goal for water and sanitation service levels. Survey and observation data were collected from 270 households and 67 water sources in rural Rwanda and were processed in relation to broader risk factors identified from the literature for the role of water and sanitation in STH infection pathways. RESULTS A significant association between higher water and sanitation service levels and lower STH infection risk profiles was found for both water and sanitation. However, variability existed within service level classifications. CONCLUSIONS Greater granularity within service level assessments is required to more precisely assess the efficacy of water and sanitation interventions in reducing STH infection risks.
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Affiliation(s)
- William Mather
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK
| | - Paul Hutchings
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK
| | - Sophie Budge
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK
| | - Paul Jeffrey
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire, MK43 0AL, UK
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21
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Alharazi TH, Al-Mekhlafi HM. A cross-sectional survey of the knowledge, attitudes and practices regarding schistosomiasis among rural schoolchildren in Taiz governorate, southwestern Yemen. Trans R Soc Trop Med Hyg 2021; 115:687-698. [PMID: 33130880 DOI: 10.1093/trstmh/traa115] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/08/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND This cross-sectional survey aimed to assess the knowledge, attitudes and practices (KAP) towards schistosomiasis among rural schoolchildren in Taiz governorate, southwestern Yemen. METHODS A total of 406 children were screened for urogenital and intestinal schistosomiasis. A pretested questionnaire was used to collect the children's demographic and socio-economic information and their KAP towards schistosomiasis. RESULTS Overall, 73 children (18%) were found to be infected by Schistosoma mansoni. None of the children were positive for Schistosoma haematobium. The prevalence of intestinal schistosomiasis was significantly higher among boys than girls (22.1% vs 12%; p=0.010). Approximately two-thirds (63.3% [257/406]) of the children had heard about schistosomiasis, however, only 38.5%, 53.6%, 28.4% and 38.1% had correct knowledge concerning the causes, symptoms, transmission and prevention, respectively. A significantly higher level of knowledge was observed among boys and Schistosoma-infected children compared with girls and non-infected children (p<0.05). However, a better level of knowledge does not seem to translate directly into the performance of hygienic practices. Multivariate logistic regression showed that sex and infection status were the significant predictors of good knowledge. CONCLUSIONS Intestinal schistosomiasis is prevalent among schoolchildren in rural Yemen. The findings reveal that children's knowledge about schistosomiasis is inadequate. Therefore, besides mass drug administration, integrated control programmes should also include health education and the provision of improved drinking water and proper sanitation.
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Affiliation(s)
- Talal H Alharazi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, University of Hail, Hail, Kingdom of Saudi Arabia.,Department of Medical Parasitology, Faculty of Medicine and Health Sciences, Taiz University, Taiz, Yemen
| | - Hesham M Al-Mekhlafi
- Medical Research Centre, Jazan University, Jazan, Kingdom of Saudi Arabia.,Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia.,Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen
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22
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Integrated Core Proteomics, Subtractive Proteomics, and Immunoinformatics Investigation to Unveil a Potential Multi-Epitope Vaccine against Schistosomiasis. Vaccines (Basel) 2021; 9:vaccines9060658. [PMID: 34208663 PMCID: PMC8235758 DOI: 10.3390/vaccines9060658] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/13/2021] [Accepted: 06/15/2021] [Indexed: 12/14/2022] Open
Abstract
Schistosomiasis is a parasitic infection that causes considerable morbidity and mortality in the world. Infections of parasitic blood flukes, known as schistosomes, cause the disease. No vaccine is available yet and thus there is a need to design an effective vaccine against schistosomiasis. Schistosoma japonicum, Schistosoma mansoni, and Schistosoma haematobium are the main pathogenic species that infect humans. In this research, core proteomics was combined with a subtractive proteomics pipeline to identify suitable antigenic proteins for the construction of a multi-epitope vaccine (MEV) against human-infecting Schistosoma species. The pipeline revealed two antigenic proteins-calcium binding and mycosubtilin synthase subunit C-as promising vaccine targets. T and B cell epitopes from the targeted proteins were predicted using multiple bioinformatics and immunoinformatics databases. Seven cytotoxic T cell lymphocytes (CTL), three helper T cell lymphocytes (HTL), and four linear B cell lymphocytes (LBL) epitopes were fused with a suitable adjuvant and linkers to design a 217 amino-acid-long MEV. The vaccine was coupled with a TLR-4 agonist (RS-09; Sequence: APPHALS) adjuvant to enhance the immune responses. The designed MEV was stable, highly antigenic, and non-allergenic to human use. Molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MMGBSA) analysis were performed to study the binding affinity and molecular interactions of the MEV with human immune receptors (TLR2 and TLR4) and MHC molecules (MHC I and MHC II). The MEV expression capability was tested in an Escherichia coli (strain-K12) plasmid vector pET-28a(+). Findings of these computer assays proved the MEV as highly promising in establishing protective immunity against the pathogens; nevertheless, additional validation by in vivo and in vitro experiments is required to discuss its real immune-protective efficacy.
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23
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Witek-McManus S, Simwanza J, Chisambi AB, Kepha S, Kamwendo Z, Mbwinja A, Samikwa L, Oswald WE, Kennedy DS, Timothy JWS, Legge H, Galagan SR, Emmanuel-Fabula M, Schaer F, Ásbjörnsdóttir K, Halliday KE, Walson JL, Juziwelo L, Bailey RL, Kalua K, Pullan RL. Epidemiology of soil-transmitted helminths following sustained implementation of routine preventive chemotherapy: Demographics and baseline results of a cluster randomised trial in southern Malawi. PLoS Negl Trop Dis 2021; 15:e0009292. [PMID: 33979325 PMCID: PMC8224978 DOI: 10.1371/journal.pntd.0009292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 06/24/2021] [Accepted: 03/05/2021] [Indexed: 11/19/2022] Open
Abstract
Malawi has successfully leveraged multiple delivery platforms to scale-up and sustain the implementation of preventive chemotherapy (PCT) for the control of morbidity caused by soil-transmitted helminths (STH). Sentinel monitoring demonstrates this strategy has been successful in reducing STH infection in school-age children, although our understanding of the contemporary epidemiological profile of STH across the broader community remains limited. As part of a multi-site trial evaluating the feasibility of interrupting STH transmission across three countries, this study aimed to describe the baseline demographics and the prevalence, intensity and associated risk factors of STH infection in Mangochi district, southern Malawi. Between October-December 2017, a community census was conducted across the catchment area of seven primary healthcare facilities, enumerating 131,074 individuals across 124 villages. A cross-sectional parasitological survey was then conducted between March-May 2018 in the censused area as a baseline for a cluster randomised trial. An age-stratified random sample of 6,102 individuals were assessed for helminthiasis by Kato-Katz and completed a detailed risk-factor questionnaire. The age-cluster weighted prevalence of any STH infection was 7.8% (95% C.I. 7.0%-8.6%) comprised predominantly of hookworm species and of entirely low-intensity infections. The presence and intensity of infection was significantly higher in men and in adults. Infection was negatively associated with risk factors that included increasing levels of relative household wealth, higher education levels of any adult household member, current school attendance, or recent deworming. In this setting of relatively high coverage of sanitation facilities, there was no association between hookworm and reported access to sanitation, handwashing facilities, or water facilities. These results describe a setting that has reduced the prevalence of STH to a very low level, and confirms many previously recognised risk-factors for infection. Expanding the delivery of anthelmintics to groups where STH infection persist could enable Malawi to move past the objective of elimination of morbidity, and towards the elimination of STH. Trial registration: NCT03014167.
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Affiliation(s)
- Stefan Witek-McManus
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - James Simwanza
- Blantyre Institute for Community Outreach, Lions Sight First Eye Hospital, Blantyre, Malawi
| | - Alvin B. Chisambi
- Blantyre Institute for Community Outreach, Lions Sight First Eye Hospital, Blantyre, Malawi
| | - Stella Kepha
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
- Pwani University Bioscience Research Centre, Pwani University, Kilifi, Kenya
| | - Zachariah Kamwendo
- Blantyre Institute for Community Outreach, Lions Sight First Eye Hospital, Blantyre, Malawi
| | - Alfred Mbwinja
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Lyson Samikwa
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - William E. Oswald
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David S. Kennedy
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Joseph W. S. Timothy
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Hugo Legge
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sean R. Galagan
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Mira Emmanuel-Fabula
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Fabian Schaer
- DeWorm3, Division of Life Sciences, Natural History Museum, London, United Kingdom
| | - Kristjana Ásbjörnsdóttir
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Katherine E. Halliday
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Judd L. Walson
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine and Department of Paediatrics, University of Washington, Seattle, Washington, United States of America
| | - Lazarus Juziwelo
- National Schistosomiasis and STH Control Programme, Community Health Sciences Unit, Ministry of Health & Population, Lilongwe, Malawi
| | - Robin L. Bailey
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Lions Sight First Eye Hospital, Blantyre, Malawi
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Rachel L. Pullan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Quality and composition of Albendazole, Mebendazole and Praziquantel available in Burkina Faso, Côte d'Ivoire, Ghana and Tanzania. PLoS Negl Trop Dis 2021; 15:e0009038. [PMID: 33493211 PMCID: PMC7861518 DOI: 10.1371/journal.pntd.0009038] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 02/04/2021] [Accepted: 12/07/2020] [Indexed: 11/19/2022] Open
Abstract
Background Even though the international combat against Neglected Tropical Diseases such as schistosomiasis or soil-transmitted helminthiases depends on reliable therapeutics, anthelminthic pharmacovigilance has been neglected on many national African drug markets. Therefore, quality and composition of Albendazole, Mebendazole and Praziquantel locally collected in Burkina Faso, Côte d’Ivoire, Ghana and Tanzania were analysed. Methods Samples of 88 different batches were obtained from randomly selected facilities. Sampling took place in Northwest Tanzania, Western Burkina Faso, Southeast Côte d’Ivoire and Southwest Ghana. Visual examination of both packaging and samples was performed according to the WHO ‘Be Aware’ tool. Products were then screened with the GPHF Minilab, consisting of tests of mass uniformity, disintegration times and thin-layer chromatography (TLC). Confirmatory tests were performed according to international pharmacopoeiae, applying assays for dissolution profiles and high-performance liquid chromatography (HPLC). Findings Despite minor irregularities, appearance of the products did not hint at falsified medicines. However, 19.6% of the brands collected in Ghana and Tanzania were not officially licensed for sale. Mass uniformity was confirmed in 53 out of 58 brands of tablets. 41 out of 56 products passed disintegration times; 10 out of the 15 failing products did not disintegrate at all. Evaluating TLC results, only 4 out of 83 batches narrowly missed specification limits, 18 batches slightly exceeded them. Not more than 46.3% (31 / 67) of the tablets assayed passed the respective pharmaceutical criteria for dissolution. HPLC findings confirmed TLC results despite shifted specification limits: 10 out of 83 tested batches contained less than 90%, none exceeded 110%. Conclusion In the four study countries, no falsified anthelminthic medicine was encountered. The active pharmaceutical ingredient was not found to either exceed or fall below specification limits. Galenic characteristics however, especially dissolution profiles, revealed great deficits. Among Neglected Tropical Diseases, schistosomiasis and soil-transmitted helminthiases are still highly prevalent and affect more than 1.5 billion people on our planet. Key players in the combat against these entities are the anthelminthic medicines Albendazole, Mebendazole and Praziquantel, which are applied in therapy and preventive chemotherapy likewise. Despite widely available in tropical regions and, particularly for both benzimidazoles, relatively cheap, their quality has been poorly monitored. By this study, we illuminated products from East (Tanzania) and West Africa (Burkina Faso, Côte d’Ivoire and Ghana) and thus extended the African map of reproducibly assessed deworming drugs. Although containing sufficient active pharmaceutical ingredient, a failure of more than 50% in galenic features significantly mars a thorough elimination of parasites from patients. Our findings emphasize the need for quality-assured products. Regular local screening, efficient and expressive confirmation of irregularities and a swift appropriate reaction by governmental authorities contribute to a successful fight against these infectious diseases. Otherwise, their sequelae pose a tremendous burden to the development and prosperity of afflicted regions–not only in heavily affected Africa but around the globe.
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25
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Manjang B, Ochola EA, Elliott SJ. The use of non-pharmaceutical interventions for the prevention and control of schistosomiasis in sub-Saharan Africa: A systematic review. Glob Public Health 2021; 17:469-482. [PMID: 33460349 DOI: 10.1080/17441692.2020.1869799] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Schistosomiasis remains a major cause of global parasitic morbidity. Current control strategies focus on pharmaceutical approaches using Mass Drug Administration (MDA) to distribute praziquantel in endemic areas of sub-Saharan Africa. Our paper systematically reviewed the literature on non-pharmaceutical interventions for enhanced schistosomiasis control. We conducted a systematic review of peer-reviewed English language literature using PubMed, Embase and Web of Science. Our search terms were limited to the year 2000 to March 2019 to reflect the period of the Millennium and Sustainable Development Goals. We initially identified 1733 publications, which were reduced to 1324 after screening by title and abstract. After the inclusion and exclusion criteria, a total of 1312 studies were excluded. Following this, we had a total of 12 articles, which we later screened by full text. Out of the twelve articles, seven were excluded for being systematic reviews or examining clinical and nutritional aspects of schistosomiasis control. We finally remained with five studies that met our inclusion criteria. Our paper indicates a gap in non-pharmaceutical based interventions for schistosomiasis control. We propose that future research addresses this gap by engaging communities in participatory approaches such as environmental sanitation, Water, Sanitation and Hygiene (WASH), health education and economic empowerment.
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Affiliation(s)
- Buba Manjang
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada
| | - Elizabeth A Ochola
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada
| | - Susan J Elliott
- Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada
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Molehin AJ. Current Understanding of Immunity Against Schistosomiasis: Impact on Vaccine and Drug Development. Res Rep Trop Med 2020; 11:119-128. [PMID: 33173371 PMCID: PMC7646453 DOI: 10.2147/rrtm.s274518] [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: 08/26/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022] Open
Abstract
Schistosomiasis is a neglected tropical disease inflicting significant morbidity in humans worldwide. The disease is caused by infections with a parasitic trematode belonging to the genus Schistosoma. Over 250 million people are currently infected globally, with an estimated disability-adjusted life-years of 1.9 million attributed to the disease. Current understanding, based on several immunological studies using experimental and human models of schistosomiasis, reveals that complex immune mechanisms play off each other in the acquisition of immune resistance to infection/reinfection. Nevertheless, the precise characteristics of these responses, the specific antigens against which they are elicited, and how these responses are intricately regulated are still being investigated. What is apparent is that immunity to schistosome infections develops slowly and over a prolonged period of time, augmented by the death of adult worms occurring naturally or by praziquantel therapy. In this review, aspects of immunity to schistosomiasis, host–parasite interactions and their impact on schistosomiasis vaccine development are discussed.
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Affiliation(s)
- Adebayo J Molehin
- Department of Internal Medicine, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.,Center for Tropical Medicine and Infectious Diseases, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
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27
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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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28
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Flammer PG, Smith AL. Intestinal helminths as a biomolecular complex in archaeological research. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190570. [PMID: 33012232 DOI: 10.1098/rstb.2019.0570] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Enteric helminths are common parasites in many parts of the world and in the past were much more widespread both geographically and socially. Many enteric helminths are relatively long-lived in the human host, often benign or of low pathogenicity while producing large numbers of environmentally resistant eggs voided in the faeces or found associated with individual remains (skeletons and mummies). The combination of helminth characters offers opportunities to the field of historical pathogen research that are quite different to that of some of the more intensively studied high impact pathogens. Historically, a wealth of studies has employed microscopic techniques to diagnose infection using the morphology of the helminth eggs. More recently, various ancient DNA (aDNA) approaches have been applied in the archaeoparasitological context and these are revolutionizing the field, allowing much more specific diagnosis as well as interrogating the epidemiology of helminths. These advances have enhanced the potential for the field to provide unique information on past populations including using diseases to consider many aspects of life (e.g. sanitation, hygiene, diet, culinary practices and other aspects of society). Here, we consider the impact of helminth archaeoparasitology and more specifically the impact and potential for application of aDNA technologies as a part of the archaeologists' toolkit. This article is part of the theme issue 'Insights into health and disease from ancient biomolecules'.
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Affiliation(s)
| | - Adrian L Smith
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
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Kayuni SA, O'Ferrall AM, Baxter H, Hesketh J, Mainga B, Lally D, Al-Harbi MH, LaCourse EJ, Juziwelo L, Musaya J, Makaula P, Stothard JR. An outbreak of intestinal schistosomiasis, alongside increasing urogenital schistosomiasis prevalence, in primary school children on the shoreline of Lake Malawi, Mangochi District, Malawi. Infect Dis Poverty 2020; 9:121. [PMID: 32867849 PMCID: PMC7456765 DOI: 10.1186/s40249-020-00736-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/07/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Intestinal schistosomiasis was not considered endemic in Lake Malawi until November 2017 when populations of Biomphalaria pfeifferi were first reported; in May 2018, emergence of intestinal schistosomiasis was confirmed. This emergence was in spite of ongoing control of urogenital schistosomiasis by preventive chemotherapy. Our current study sought to ascertain whether intestinal schistosomiasis is transitioning from emergence to outbreak, to judge if stepped-up control interventions are needed. METHODS During late-May 2019, three cross-sectional surveys of primary school children for schistosomiasis were conducted using a combination of rapid diagnostic tests, parasitological examinations and applied morbidity-markers; 1) schistosomiasis dynamics were assessed at Samama (n = 80) and Mchoka (n = 80) schools, where Schistosoma mansoni was first reported, 2) occurrence of S. mansoni was investigated at two non-sampled schools, Mangochi Orphan Education and Training (MOET) (n = 60) and Koche (n = 60) schools, where B. pfeifferi was nearby, and 3) rapid mapping of schistosomiasis, and B. pfeifferi, conducted across a further 8 shoreline schools (n = 240). After data collection, univariate analyses and Chi-square testing were performed, followed by binary logistic regression using generalized linear models, to investigate epidemiological associations. RESULTS In total, 520 children from 12 lakeshore primary schools were examined, mean prevalence of S. mansoni by 'positive' urine circulating cathodic antigen (CCA)-dipsticks was 31.5% (95% confidence interval [CI]: 27.5-35.5). Upon comparisons of infection prevalence in May 2018, significant increases at Samama (relative risk [RR] = 1.7, 95% CI: 1.4-2.2) and Mchoka (RR = 2.7, 95% CI: 1.7-4.3) schools were observed. Intestinal schistosomiasis was confirmed at MOET (18.3%) and Koche (35.0%) schools, and in all rapid mapping schools, ranging from 10.0 to 56.7%. Several populations of B. pfeifferi were confirmed, with two new eastern shoreline locations noted. Mean prevalence of urogenital schistosomiasis was 24.0% (95% CI: 20.3-27.7). CONCLUSIONS We notify that intestinal schistosomiasis, once considered non-endemic in Lake Malawi, is now transitioning from emergence to outbreak. Once control interventions can resume after coronavirus disease 2019 (COVID-19) suspensions, we recommend stepped-up preventive chemotherapy, with increased community-access to treatments, alongside renewed efforts in appropriate environmental control.
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Affiliation(s)
- Sekeleghe A Kayuni
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK.,Medi Clinic Limited, Medical Aid Society of Malawi (MASM), 22 Lower Sclatter Road, P.O. Box 1254, Blantyre, Malawi
| | - Angus M O'Ferrall
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Hamish Baxter
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Josie Hesketh
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Bright Mainga
- Laboratory Department, Mangochi District Hospital, P.O. Box 42, Mangochi, Malawi
| | - David Lally
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Blantyre, Malawi
| | | | - E James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK
| | - Lazarus Juziwelo
- National Schistosomiasis and STH Control Programme, Ministry of Health, Lilongwe, Malawi
| | - Janelisa Musaya
- Malawi Liverpool Wellcome Trust Programme of Clinical Tropical Research, Queen Elizabeth Central Hospital, College of Medicine, P.O. Box 30096, Blantyre, Malawi.,Department of Basic Medical Sciences, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Peter Makaula
- Research for Health Environment and Development, P.O. Box 345, Mangochi, Malawi
| | - J Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, L3 5QA, Liverpool, UK.
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Mutapi F, Tagwireyi P, Lim R, Mangwanda B, Fourier C, Mduluza T. Positive impact of preventative chemotherapy during a national helminth control program: Perception and KAP. PLoS Negl Trop Dis 2020; 14:e0008494. [PMID: 32833994 PMCID: PMC7446881 DOI: 10.1371/journal.pntd.0008494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/18/2020] [Indexed: 11/18/2022] Open
Abstract
Helminth control at the national level is currently based on mass drug administration (MDA) programs. Perception of the MDA programs for helminth control by the affected populations influences compliance and future designs of the programs. We determined the perception of Zimbabwe's National Helminth Control Program (2012-2017) with a specific focus on schistosomiasis in the school children treated with praziquantel, schoolteachers and village health workers (VHW). The study enrolled 409 children from Grades 6 and 7 who had the full benefit of the 6 years of MDA from 2012 to 2017. Thirty-six schoolteachers and 22 VHW serving the schools were also recruited. A structured questionnaire developed in English, translated into the local language Shona, and validated prior to the study was administered to the children and the adults. The questions focused on the perceived impact on health, school attendance and performance and Knowledge Attitudes and Practice (KAP) among the school children. Data were captured electronically on android platforms using the Open Data Kit. Overall, 84% of the children responded that their awareness of schistosomiasis (transmission, disease, treatment and infection avoidance) had improved because of participating in the MDAs. Of the 151 children self-diagnosed with schistosomiasis, 74% reported that their health had improved following treatment with praziquantel. This included resolution of haematuria, painful urination, sore stomach, tiredness and falling asleep during class lessons. The children and teachers reported improvements in both pupil school attendance and performance at school while the VHW and teachers reported an increase in health-seeking behaviour amongst the school children for schistosomiasis treatment in-between MDAs. The majority of VHW (96%) reported improvement in handwashing behaviour, schistosomiasis awareness (96%) and treatment uptake (91%) within the communities where the school children belonged. However, only 59% of the VHW reported improvement in toilet use while only 50% of the VHW reported improvement in clean water use within their communities. This study indicated that the surveyed children perceived the MDA program had improved their health, school attendance, school performance and awareness of schistosomiasis. The VHW also perceived that the MDA program had improved the community KAP.
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Affiliation(s)
- Francisca Mutapi
- Institute of Immunology & Infection Research, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
- NIHR Global Health Research Unit Tackling Infections to Benefit Africa (TIBA) at the University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
- * E-mail:
| | - Paradzayi Tagwireyi
- Department of Geography and Environmental Science, Geo-information and Earth Observation Centre, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe
| | - Rivka Lim
- Institute of Immunology & Infection Research, University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
- NIHR Global Health Research Unit Tackling Infections to Benefit Africa (TIBA) at the University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Blessing Mangwanda
- Department of Geography and Environmental Science, Geo-information and Earth Observation Centre, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe
| | - Charmaine Fourier
- Department of Biochemistry, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe
| | - Takafira Mduluza
- Department of Biochemistry, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe
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Archer J, O’Halloran L, Al-Shehri H, Summers S, Bhattacharyya T, Kabaterine NB, Atuhaire A, Adriko M, Arianaitwe M, Stewart M, LaCourse EJ, Webster BL, Bustinduy AL, Stothard JR. Intestinal Schistosomiasis and Giardiasis Co-Infection in Sub-Saharan Africa: Can a One Health Approach Improve Control of Each Waterborne Parasite Simultaneously? Trop Med Infect Dis 2020; 5:E137. [PMID: 32854435 PMCID: PMC7558413 DOI: 10.3390/tropicalmed5030137] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/16/2020] [Accepted: 08/19/2020] [Indexed: 12/14/2022] Open
Abstract
Both intestinal schistosomiasis and giardiasis are co-endemic throughout many areas of sub-Saharan Africa, significantly impacting the health of millions of children in endemic areas. While giardiasis is not considered a neglected tropical disease (NTD), intestinal schistosomiasis is formally grouped under the NTD umbrella and receives significant advocacy and financial support for large-scale control. Although there are differences in the epidemiology between these two diseases, there are also key similarities that might be exploited within potential integrated control strategies permitting tandem interventions. In this review, we highlight these similarities and discuss opportunities for integrated control of giardiasis in low and middle-income countries where intestinal schistosomiasis is co-endemic. By applying new, advanced methods of disease surveillance, and by improving the provision of water, sanitation and hygiene (WASH) initiatives, (co)infection with intestinal schistosomiasis and/or giardiasis could not only be more effectively controlled but also better understood. In this light, we appraise the suitability of a One Health approach targeting both intestinal schistosomiasis and giardiasis, for if adopted more broadly, transmission of both diseases could be reduced to gain improvements in health and wellbeing.
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Affiliation(s)
- John Archer
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK; (J.A.); (B.L.W.)
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
| | - Lisa O’Halloran
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
| | - Hajri Al-Shehri
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
- Department of Tropical Infectious Diseases, Ministry of Health, Asir District, Abha 61411, Saudi Arabia
| | - Shannan Summers
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; (S.S.); (T.B.); (A.L.B.)
| | - Tapan Bhattacharyya
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; (S.S.); (T.B.); (A.L.B.)
| | - Narcis B. Kabaterine
- Vector Control Division, Ministry of Health, Kampala 759125, Uganda; (N.B.K.); (A.A.); (M.A.); (M.A.)
| | - Aaron Atuhaire
- Vector Control Division, Ministry of Health, Kampala 759125, Uganda; (N.B.K.); (A.A.); (M.A.); (M.A.)
| | - Moses Adriko
- Vector Control Division, Ministry of Health, Kampala 759125, Uganda; (N.B.K.); (A.A.); (M.A.); (M.A.)
| | - Moses Arianaitwe
- Vector Control Division, Ministry of Health, Kampala 759125, Uganda; (N.B.K.); (A.A.); (M.A.); (M.A.)
| | - Martyn Stewart
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
| | - E. James LaCourse
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
| | - Bonnie L. Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD, UK; (J.A.); (B.L.W.)
| | - Amaya L. Bustinduy
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK; (S.S.); (T.B.); (A.L.B.)
| | - J. Russell Stothard
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK; (L.O.); (H.A.-S.); (M.S.); (E.J.L.)
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Connecting Female Genital Schistosomiasis and Menstrual Hygiene Initiatives. Trends Parasitol 2020; 36:410-412. [PMID: 32298628 DOI: 10.1016/j.pt.2020.02.007] [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] [Received: 01/25/2020] [Revised: 02/25/2020] [Accepted: 02/25/2020] [Indexed: 11/20/2022]
Abstract
Effective future control of female genital schistosomiasis (FGS) requires an integrated and multisectoral approach, bringing together HIV, sexual and reproductive health, and reproductive rights sectors. In this article, an underappreciated but important connection between FGS and menstrual hygiene initiatives in Africa is highlighted.
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Nasr NA, Al-Mekhlafi HM, Lim YAL, Elyana FN, Sady H, Atroosh WM, Dawaki S, Al-Delaimy AK, Al-Areeqi MA, Wehaish AA, Anuar TS, Mahmud R. A holistic approach is needed to control the perpetual burden of soil-transmitted helminth infections among indigenous schoolchildren in Malaysia. Pathog Glob Health 2020; 114:145-159. [PMID: 32249689 DOI: 10.1080/20477724.2020.1747855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
A cross-sectional survey was conducted among 1,142 Orang Ali schoolchildren in six states of Peninsular Malaysia to investigate the current prevalence and risk factors of STH infections. Faecal samples were examined using direct smear, formalin-ether sedimentation, Kato-Katz, and Harada-Mori methods. A pre-tested questionnaire was used to collect information on the demographic, socioeconomic, personal hygiene, and health status of the participants. Overall, 70.1% (95% CI = 67.4, 72.7) of the participants were infected with at least one of the STH species. The prevalence of Ascaris lumbricoides, Trichuris trichiura, and hookworm infections was 63.1%, 61.8% and 11.5%, respectively. Moderate-to-heavy STH infections accounted for 61.3% of the total infections. Univariate and logistic regression analyses revealed different sets of risk factors, with age (> 10 years) being the significant risk factor of all three STH species. Moreover, other species-specific risk factors were identified including being a member of the Senoi tribe, family size (≥ 7 members), school size (150-250 pupils), maternal unemployment, unimproved source of drinking water, lacking improved toilet in the house, inadequate WASH facilities at school, not washing hands before eating, and not washing fruits before eating; presence of domestic animals, and not wearing shoes when outside. The high prevalence of STH infections found in the study population exceeds the WHO policy intervention threshold (20% prevalence). Thus, an innovative holistic approach should be adopted to control STH infections among these children as part of the efforts to improve the quality of life of the entire Orang Asli population. .
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Affiliation(s)
- Nabil A Nasr
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Hesham M Al-Mekhlafi
- Medical Research Centre, Jazan University, Jazan, Kingdom of Saudi Arabia.,Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen
| | - Yvonne A L Lim
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Fatin Nur Elyana
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Hany Sady
- Department of Medical Laboratories, Faculty of Medical Sciences, Hodeidah University, Hodeidah, Yemen
| | - Wahib M Atroosh
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University of Aden, Aden, Yemen
| | - Salwa Dawaki
- School of Health Technology, Nassarawa, Kano, Nigeria
| | - Ahmed K Al-Delaimy
- Department of Family and Community Medicine, College of Medicine, University of Anbar, Ramadi, Iraq
| | - Mona A Al-Areeqi
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.,Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen
| | - Abkar A Wehaish
- Department of Social and Preventive Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tengku Shahrul Anuar
- Centre of Medical Laboratory Technology, Faculty of Health Sciences, Universiti Teknologi MARA, Selangor, Malaysia.,Integrative Pharmacogenomics Institute, Universiti Teknologi MARA, Selangor, Malaysia
| | - Rohela Mahmud
- Department of Parasitology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
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Molehin AJ. Schistosomiasis vaccine development: update on human clinical trials. J Biomed Sci 2020; 27:28. [PMID: 31969170 PMCID: PMC6977295 DOI: 10.1186/s12929-020-0621-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/16/2020] [Indexed: 01/13/2023] Open
Abstract
Schistosomiasis causes significant levels of morbidity and mortality in many geographical regions of the world. The disease is caused by infections with parasitic blood flukes known as schistosomes. The control of schistosomiasis over the last several decades has been centered on the mass drug administration (MDA) of praziquantel (PZQ), which is the only drug currently available for treatment. Despite the concerted efforts of MDA programs, the prevalence and transmission of schistosomiasis has remained largely unchecked due to the fact that PZQ is ineffective against juvenile schistosomes, does not prevent re-infection and the emergence of PZQ-resistant parasites. In addition, other measures such as the water, sanitation and hygiene programs and snail intermediate hosts control have had little to no impact. These drawbacks indicate that the current control strategies are severely inadequate at interrupting transmission and therefore, implementation of other control strategies are required. Ideally, an efficient vaccine is what is needed for long term protection thereby eliminating the current efforts of repeated mass drug administration. However, the general consensus in the field is that the integration of a viable vaccine with MDA and other control measures offer the best chance of achieving the goal of schistosomiasis elimination. This review focuses on the present status of schistosomiasis vaccine candidates in different phases of human clinical trials and provide some insight into future vaccine discovery and design.
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Affiliation(s)
- Adebayo J Molehin
- Center for Tropical Medicine and Infectious Diseases, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, USA. .,Department of Internal Medicine, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, USA.
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Betson M, Alonte AJI, Ancog RC, Aquino AMO, Belizario VY, Bordado AMD, Clark J, Corales MCG, Dacuma MG, Divina BP, Dixon MA, Gourley SA, Jimenez JRD, Jones BP, Manalo SMP, Prada JM, van Vliet AHM, Whatley KCL, Paller VGV. Zoonotic transmission of intestinal helminths in southeast Asia: Implications for control and elimination. ADVANCES IN PARASITOLOGY 2020; 108:47-131. [PMID: 32291086 DOI: 10.1016/bs.apar.2020.01.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intestinal helminths are extremely widespread and highly prevalent infections of humans, particularly in rural and poor urban areas of low and middle-income countries. These parasites have chronic and often insidious effects on human health and child development including abdominal problems, anaemia, stunting and wasting. Certain animals play a fundamental role in the transmission of many intestinal helminths to humans. However, the contribution of zoonotic transmission to the overall burden of human intestinal helminth infection and the relative importance of different animal reservoirs remains incomplete. Moreover, control programmes and transmission models for intestinal helminths often do not consider the role of zoonotic reservoirs of infection. Such reservoirs will become increasingly important as control is scaled up and there is a move towards interruption and even elimination of parasite transmission. With a focus on southeast Asia, and the Philippines in particular, this review summarises the major zoonotic intestinal helminths, risk factors for infection and highlights knowledge gaps related to their epidemiology and transmission. Various methodologies are discussed, including parasite genomics, mathematical modelling and socio-economic analysis, that could be employed to improve understanding of intestinal helminth spread, reservoir attribution and the burden associated with infection, as well as assess effectiveness of interventions. For sustainable control and ultimately elimination of intestinal helminths, there is a need to move beyond scheduled mass deworming and to consider animal and environmental reservoirs. A One Health approach to control of intestinal helminths is proposed, integrating interventions targeting humans, animals and the environment, including improved access to water, hygiene and sanitation. This will require coordination and collaboration across different sectors to achieve best health outcomes for all.
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Affiliation(s)
- Martha Betson
- University of Surrey, Guildford, Surrey, United Kingdom.
| | | | - Rico C Ancog
- University of the Philippines Los Baños, Laguna, Philippines
| | | | | | | | - Jessica Clark
- University of Surrey, Guildford, Surrey, United Kingdom
| | | | | | - Billy P Divina
- University of the Philippines Los Baños, Laguna, Philippines
| | | | | | | | - Ben P Jones
- University of Surrey, Guildford, Surrey, United Kingdom
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Tinkler SH. Preventive chemotherapy and anthelmintic resistance of soil-transmitted helminths - Can we learn nothing from veterinary medicine? One Health 2019; 9:100106. [PMID: 31956691 PMCID: PMC6957790 DOI: 10.1016/j.onehlt.2019.100106] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 12/21/2022] Open
Abstract
Current parasite control programs in veterinary species have moved away from mass anthelmintic treatment approaches due to the emergence of significant anthelmintic resistance (AR), and the availability of few classes of anthelmintics. A number of parallels between livestock and human helminths exist that warn of the risk of AR in human soil-transmitted helminthiases, yet current public health interventions continue to prioritize mass treatment strategies, a known risk factor for AR. This review discusses the existing parallels between human and animal helminth biology and management, along with current public health recommendations and strategies for helminth control in humans. The effectiveness of current recommendations and alternative management strategies are considered.
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Choudhary S, Tipton JG, Abongwa M, Brewer MT, Chelladurai JJ, Musselman N, Martin RJ, Robertson AP. Pharmacological characterization of a homomeric nicotinic acetylcholine receptor formed by Ancylostoma caninum ACR-16. INVERTEBRATE NEUROSCIENCE : IN 2019; 19:11. [PMID: 31486912 PMCID: PMC7869652 DOI: 10.1007/s10158-019-0231-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/17/2019] [Indexed: 01/07/2023]
Abstract
Parasitic nematode infections are treated using anthelmintic drugs, some of which target nicotinic acetylcholine receptors (nAChRs) located in different parasite tissues. The limited arsenal of anthelmintic agents and the prevalence of drug resistance imply that future defense against parasitic infections will depend on the discovery of novel targets and therapeutics. Previous studies have suggested that Ascaris suum ACR-16 nAChRs are a suitable target for the development of antinematodal drugs. In this study, we characterized the pharmacology of the Ancylostoma caninum ACR-16 receptor using two-electrode voltage-clamp electrophysiology. This technique allowed us to study the effects of cholinergic agonists and antagonists on the nematode nAChRs expressed in Xenopus laevis oocytes. Aca-ACR-16 was not sensitive to many of the existing cholinomimetic anthelmintics (levamisole, oxantel, pyrantel, and tribendimidine). 3-Bromocytisine was the most potent agonist (> 130% of the control acetylcholine current) on the Aca-ACR-16 nAChR but, unlike Asu-ACR-16, oxantel did not activate the receptor. The mean time constants of desensitization for agonists on Aca-ACR-16 were longer than the rates observed in Asu-ACR-16. In contrast to Asu-ACR-16, the A. caninum receptor was completely inhibited by DHβE and moderately inhibited by α-BTX. In conclusion, we have successfully reconstituted a fully functional homomeric nAChR, ACR-16, from A. caninum, a model for human hookworm infections. The pharmacology of the receptor is distinct from levamisole-sensitive nematode receptors. The ACR-16 homologue also displayed some pharmacological differences from Asu-ACR-16. Hence, A. caninum ACR-16 may be a valid target site for the development of anthelmintics against hookworm infections.
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Affiliation(s)
- Shivani Choudhary
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - James G Tipton
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Melanie Abongwa
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Matthew T Brewer
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Jeba Jesudoss Chelladurai
- Department of Veterinary Pathology, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Nicole Musselman
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Richard J Martin
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA
| | - Alan P Robertson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA.
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Sacolo-Gwebu H, Kabuyaya M, Chimbari M. Knowledge, attitudes and practices on schistosomiasis and soil-transmitted helminths among caregivers in Ingwavuma area in uMkhanyakude district, South Africa. BMC Infect Dis 2019; 19:734. [PMID: 31438865 PMCID: PMC6704662 DOI: 10.1186/s12879-019-4253-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 07/03/2019] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Schistosomiasis and soil-transmitted helminth infections are among the most chronic infections worldwide. Based on their demonstrable impact on human health, the WHO recently recommended the implementation of robust strategies aimed at controlling or eliminating schistosomiasis and soil-transmitted helminths by 2020. The implementation of this strategy, however, warrants a clear understanding of the community's knowledge, attitudes and practices in relation to these infections. This study sought to identify sociocultural gaps that should be addressed to ensure the success of cost-effective community-based schistosomiasis-soil-transmitted helminths control and elimination programs. METHODS This was a cross-sectional mixed methodology study. Quantitative data were collected using a structured questionnaire from 442 caregivers of preschool aged children. In-depth interviews and focus group discussions were conducted among caregivers, preschool teachers, traditional authorities and community caregivers. All interviews were captured using an audio recorder to maximize accuracy. Quantitative data were analysed using bivariate and multivariate techniques while qualitative data were analysed thematically. RESULTS Findings reflected inadequate knowledge, attitudes and practices in relation to schistosomiasis and soil-transmitted helminths while awareness of schistosomiasis and soil-transmitted helminths was high (87.1 and 79.2% respectively). Correct knowledge on transmission, prevention, signs and symptoms and life cycle was low (below 50%) for both infections among those who had heard of the disease. From multivariate analysis, being aged at least 35 years increased the odds of reporting good practices on schistosomiasis by 65% (COR 1.652, 95% CI: 1.073-2.543) while receiving health information through community meetings (COR 0.072, 95% CI: 0.010-0.548) significantly reduced the odds of having good knowledge on schistosomiasis. CONCLUSIONS These findings are valuable in designing behavioural change approaches towards enhancing health outcomes through community-based interventions to ensure effective control and elimination of schistosomiasis and soil-transmitted helminths. There is a critical need for channelling efforts towards making health education the core of schistosomiasis and soil-transmitted helminths programs aimed at achieving intensified control or elimination of these infections by 2020.
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Affiliation(s)
- Hlengiwe Sacolo-Gwebu
- School of Nursing and Public Health, College of Health Sciences, Howard College Campus, University of KwaZulu-Natal, Durban, South Africa
| | - Muhubiri Kabuyaya
- School of Nursing and Public Health, College of Health Sciences, Howard College Campus, University of KwaZulu-Natal, Durban, South Africa
| | - Moses Chimbari
- School of Nursing and Public Health, College of Health Sciences, Howard College Campus, University of KwaZulu-Natal, Durban, South Africa
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Abstract
The multifaceted interactions occurring between gastrointestinal (GI) parasitic helminths and the host gut microbiota are emerging as a key area of study within the broader research domain of host-pathogen relationships. Over the past few years, a wealth of investigations has demonstrated that GI helminths interact with the host gut flora, and that such interactions result in modifications of the host immune and metabolic statuses. Nevertheless, whilst selected changes in gut microbial composition are consistently observed in response to GI helminth infections across several host-parasite systems, research in this area to date is largely characterised by inconsistent findings. These discrepancies are particularly evident when data from studies of GI helminth-microbiota interactions conducted in humans from parasite-endemic regions are compared. In this review, we provide an overview of the main sources of variance that affect investigations on helminth-gut microbiota interactions in humans, and propose a series of methodological approaches that, whilst accounting for the inevitable constraints of fieldwork, are aimed at minimising confounding factors and draw biologically meaningful interpretations from highly variable datasets.
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Khan MS, Pullan R, Okello G, Nyikuri M, McKee M, Balabanova D. "For how long are we going to take the tablets?" Kenyan stakeholders' views on priority investments to sustainably tackle soil-transmitted helminths. Soc Sci Med 2019; 228:51-59. [PMID: 30875544 DOI: 10.1016/j.socscimed.2019.02.050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 02/24/2019] [Accepted: 02/26/2019] [Indexed: 11/18/2022]
Abstract
Recent global commitments to shift responsibility for Neglected Tropical Disease (NTD) control to affected countries reflect a renewed emphasis on sustainability, away from aid-dependency. This calls for a better understanding of how domestic stakeholders perceive investments in different strategies for NTD control. Soil transmitted helminths (STH) are among the NTDs targeted for elimination as a public health problem by international agencies through mass drug administration, provided periodically to at-risk population groups, often using drugs donated by pharmaceutical companies. This study was conducted in Kenya at a time when responsibilities for long running STH programmes were transitioning from external to national and sub-national agencies. Following an initial assessment in which we identified key domestic stakeholders and reviewed relevant scientific and government documents, the perspectives of stakeholders working in health, education, community engagement and sanitation were investigated through semi-structured interviews with national level policymakers, county level policymakers, and frontline implementers in one high-STH burden county, Kwale. Our conceptual framework on sustainability traced a progression in thinking, from ensuring financial stability through the technical ability to adapt to changing circumstances, and ultimately to a situation where a programme is prioritised by domestic policymakers because empowered communities demand it. It was clear from our interviews that most Kenyan stakeholders sought to be at the final stage in this progression. Interviewees criticised long-term investment in mass drug administration, the approach favoured predominantly by external agencies, for failing to address underlying causes of STH. Instead they identified three synergistic priority areas for investment: changes in institutional structures and culture to reduce working in silos; building community demand and ownership; and increased policymaker engagement on underlying socioeconomic and environmental causes of STH. Although challenging to implement, the shift in responsibility from external agencies to domestic stakeholders may lead to emergence of new strategic directions.
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Affiliation(s)
- Mishal S Khan
- Faculty of Public Health & Policy, London School of Hygiene & Tropical Medicine (LSHTM), UK.
| | - Rachel Pullan
- Faculty of Infectious and Tropical Diseases, LSHTM, UK
| | - George Okello
- KEMRI-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Mary Nyikuri
- Institute of Health Care Management, Strathmore University, Kenya
| | - Martin McKee
- Faculty of Public Health & Policy, London School of Hygiene & Tropical Medicine (LSHTM), UK
| | - Dina Balabanova
- Faculty of Public Health & Policy, London School of Hygiene & Tropical Medicine (LSHTM), UK
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Asian Schistosomiasis: Current Status and Prospects for Control Leading to Elimination. Trop Med Infect Dis 2019; 4:tropicalmed4010040. [PMID: 30813615 PMCID: PMC6473711 DOI: 10.3390/tropicalmed4010040] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 02/12/2019] [Accepted: 02/12/2019] [Indexed: 12/22/2022] Open
Abstract
Schistosomiasis is an infectious disease caused by helminth parasites of the genus Schistosoma. Worldwide, an estimated 250 million people are infected with these parasites with the majority of cases occurring in sub-Saharan Africa. Within Asia, three species of Schistosoma cause disease. Schistosoma japonicum is the most prevalent, followed by S. mekongi and S. malayensis. All three species are zoonotic, which causes concern for their control, as successful elimination not only requires management of the human definitive host, but also the animal reservoir hosts. With regard to Asian schistosomiasis, most of the published research has focused on S. japonicum with comparatively little attention paid to S. mekongi and even less focus on S. malayensis. In this review, we examine the three Asian schistosomes and their current status in their endemic countries: Cambodia, Lao People's Democratic Republic, Myanmar, and Thailand (S. mekongi); Malaysia (S. malayensis); and Indonesia, People's Republic of China, and the Philippines (S. japonicum). Prospects for control that could potentially lead to elimination are highlighted as these can inform researchers and disease control managers in other schistosomiasis-endemic areas, particularly in Africa and the Americas.
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Vaz Nery S, Clarke NE, Richardson A, Traub R, McCarthy JS, Gray DJ, Vallely AJ, Williams GM, Andrews RM, Campbell SJ, Clements ACA. Risk factors for infection with soil-transmitted helminths during an integrated community level water, sanitation, and hygiene and deworming intervention in Timor-Leste. Int J Parasitol 2019; 49:389-396. [PMID: 30802450 DOI: 10.1016/j.ijpara.2018.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 01/21/2023]
Abstract
Water, sanitation and hygiene interventions have been advocated as important complements to deworming programs to improve soil-transmitted helminth control. Evidence for the impact of water, sanitation and hygiene on soil-transmitted helminth infections is mixed, and based mainly on cross-sectional studies. In this study, we assessed associations between individual- and household-level water, sanitation and hygiene variables and soil-transmitted helminth infections, using data collected during the 2 year follow-up study period of the WASH for WORMS randomised controlled trial in Timor-Leste. Data were collected across four surveys, conducted at 6 monthly intervals in 23 communities. We analysed water, sanitation and hygiene and sociodemographic variables as risk factors for infection with Necator americanus, Ascaris spp., and undifferentiated soil-transmitted helminth infection, using generalised linear mixed models to account for clustering at community, household and participant levels. Water, sanitation and hygiene risk factors were examined both concurrently and with a 6 month lag period that coincided with the most recent deworming. The analysis included 2333 participants. Factors associated with N. americanus infection included age group, male sex (adjusted odds ratio (aOR) 3.1, 95% confidence interval (CI) 2.4-4.2), working as a farmer (aOR 1.7, 95% CI 1.2-2.4), and completing secondary school or higher (aOR 0.29, 95% CI 0.16-0.53). Risk factors for Ascaris spp. infection included age group, living in a dwelling with more than six people (aOR 1.6, 95% CI 1.1-2.3), having a tube well or borehole as the household water source (aOR 3.7, 95% CI 1.3-10.8), and using a latrine shared between households 6 months previously (aOR 2.3, 95% CI 1.2-4.3). Handwashing before eating was protective against infection with any soil-transmitted helminth (aOR 0.79, 95% CI 0.65-0.95). In the context of regular deworming, few water, sanitation and hygiene-related factors were associated with soil-transmitted helminth infections. Future research examining the role of water, sanitation and hygiene in soil-transmitted helminth transmission is required, particularly in low transmission settings after cessation of deworming. Identifying improved indicators for measuring water, sanitation and hygiene behaviours is also a key priority.
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Affiliation(s)
- Susana Vaz Nery
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia.
| | - Naomi E Clarke
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia
| | - Alice Richardson
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia
| | - Rebecca Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC 3052, Australia
| | - James S McCarthy
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia; School of Medicine, University of Queensland, Brisbane, QLD 4006, Australia
| | - Darren J Gray
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia
| | - Andrew J Vallely
- Kirby Institute, University of New South Wales, Sydney, NSW 2052, Australia
| | - Gail M Williams
- School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia
| | - Ross M Andrews
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia; Menzies School of Health Research, Charles Darwin University, Darwin, NT 0811, Australia
| | - Suzy J Campbell
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia
| | - Archie C A Clements
- Research School of Population Health, Australian National University, Canberra ACT 0200, Australia
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Dunn JC, Bettis AA, Wyine NY, Lwin AMM, Tun A, Maung NS, Anderson RM. Soil-transmitted helminth reinfection four and six months after mass drug administration: results from the delta region of Myanmar. PLoS Negl Trop Dis 2019; 13:e0006591. [PMID: 30768602 PMCID: PMC6395004 DOI: 10.1371/journal.pntd.0006591] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 02/28/2019] [Accepted: 01/24/2019] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Mass drug administration (MDA), targeted at school-aged children (SAC) is the method recommended by the World Health Organization for the control of morbidity induced by soil-transmitted helminth (STH) infection in endemic countries. However, MDA does not prevent reinfection between treatment rounds and research suggests that only treating SAC will not be sufficient to bring prevalence to low levels and possibly interrupt transmission of STH. In countries with endemic infection, such as Myanmar, the coverage, who is targeted, and rates of reinfection will determine how effective MDA is in suppressing transmission in the long-term. METHODS/PRINCIPAL FINDINGS In this paper, data from an epidemiological study on STH, comprising three surveys conducted between June 2015 and June 2016 in the delta region of Myanmar, are analysed to determine how STH prevalence and intensity in the study community changes over the course of a year, including reinfection after two MDA rounds in which the whole study sample (all age groups, n = 523) were treated with albendazole. Prevalence in the first survey (August 2015) was 27.92% for any STH, 5.54% for Ascaris lumbricoides, 17.02% for Trichuris trichiura and 9.75% for hookworm. Over the year (survey one to survey three), prevalence of any STH decreased by 8.99% (P < 0.001) and mean EPG significantly decreased for T. trichiura (P < 0.01) and hookworm (P < 0.001). Risk ratios (RRs) for a four-month reinfection period (August to December) were statistically significant and were below one, indicating that STH prevalence had not bounced back to the prevalence levels recorded immediately prior to the last round of treatment (any STH RR = 0.67, 95% CI 0.56-0.81; A. lumbricoides RR = 0.31, 95% CI 0.16-0.59; T. trichiura RR = 0.70, 95% CI 0.55-0.88; hookworm RR = 0.69, 95% CI 0.50-0.95). The only statistically significant RR for the six-month reinfection period (December to June) was for A. lumbricoides infection in SAC (RR = 2.67, 95% CI 1.37-5.21). All six-month RRs were significantly higher than four-month RRs (P < 0.05). Evidence of predisposition to infection (low and high), as measured by the Kendall Tau-b statistic, was found for all species overall and within most age groups stratifications, except for hookworm infection in preschool-aged children. CONCLUSIONS/SIGNIFICANCE This study demonstrates that, for certain demographic groups, a six-month gap between MDA in these communities is enough time for STH infection to return to STH prevalence levels recorded immediately before the previous MDA round, and that on average the same individuals are being consistently infected between MDA rounds.
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Affiliation(s)
- Julia C. Dunn
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Alison A. Bettis
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | - Nay Yee Wyine
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
| | | | - Aung Tun
- Ministry of Health and Sports, Nyapyitaw, Myanmar
| | | | - Roy M. Anderson
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
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