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Kargbo-Labour I, Redwood-Sawyerr V, Conteh A, Chop E, Bah MS, Koroma A, Kabia U, Klein L, Juneja S, Houck P, Reid S, Evans D, Weaver AM, Phillips AE, Zhang Y. Re-assessment of schistosomiasis in nine endemic districts with cluster sampling in Sierra Leone. Front Public Health 2024; 12:1415486. [PMID: 38932788 PMCID: PMC11199885 DOI: 10.3389/fpubh.2024.1415486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
Background Baseline mapping showed that schistosomiasis was highly/moderately endemic in nine districts in Sierra Leone. Mass drug administration (MDA) with praziquantel started in 2009, and after multiple rounds of treatment, an impact assessment was conducted in 2016 followed by a second re-assessment in 2022 using cluster sampling to provide more granular data for refining chiefdom (sub-district) treatment strategies. Methods On average, 20 rural villages were systematically selected per district by probability proportional to population size across the nine districts. Surveys were conducted in schools, and 24 school children aged between 5 and 14 years were randomly selected, with an equal number of boys and girls. One stool sample and one urine sample were collected per child. Two Kato-Katz slides were examined per stool for Schistosoma mansoni infection. Hemastix strips were used as a proxy for S. haematobium infection with urine filtration used for egg counts on hematuria-positive samples. Results In total, 4,736 stool samples and 4,618 urine samples were examined across 200 schools in 125 chiefdoms. Overall, the prevalence of S. mansoni was 16.3% (95% CI: 15.3-17.4%), while the overall prevalence of S. haematobium was 2.0% (95% CI: 1.6-2.4%) by hematuria. The prevalence of heavy infections for S. mansoni and S. haematobium was 1.5% (95% CI: 1.1-1.9%) and 0.02% (95% CI: 0.0-0.14%), respectively. Among 125 chiefdoms surveyed, the overall schistosomiasis prevalence was <10% in 65 chiefdoms, 10-49.9% in 47 chiefdoms, and ≥ 50% in 13 chiefdoms. There was a mixed relationship between schistosomiasis in school children and WASH access in schools. Conclusion Sierra Leone has made significant progress in reducing schistosomiasis prevalence across the country after a decade of MDA intervention. However, high prevalence remains in some hotspot chiefdoms. The next steps are for the national program to investigate and address any potential issues such as low coverage or poor knowledge of schistosomiasis risk behaviors and, where appropriate, consider broadening to community-wide treatment in hotspot chiefdoms or communities.
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Affiliation(s)
- Ibrahim Kargbo-Labour
- National Neglected Tropical Disease Control Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Abdulai Conteh
- National Neglected Tropical Disease Control Program, Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | | | | | | | | | | | | | - Steven Reid
- Helen Keller International, New York, NY, United States
| | - Darin Evans
- United States Agency for International Development, Washington, DC, United States
| | | | | | - Yaobi Zhang
- Helen Keller International, New York, NY, United States
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Tallima H, Tadros MM, El Ridi R. Differential protective impact of peptide vaccine formulae targeting the lung- and liver-stage of challenge Schistosoma mansoni infection in mice. Acta Trop 2024; 254:107208. [PMID: 38621620 DOI: 10.1016/j.actatropica.2024.107208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/11/2024] [Accepted: 04/05/2024] [Indexed: 04/17/2024]
Abstract
The study aimed to elicit protective immune responses against murine schistosomiasis mansoni at the parasite lung- and liver stage. Two peptides showing amino acid sequence similarity to gut cysteine peptidases, which induce strong memory immune effectors in the liver, were combined with a peptide based on S. mansoni thioredoxin peroxidase (TPX), a prominent lung-stage schistosomula excretory-secretory product, and alum as adjuvant. Only one of the 2 cysteine peptidases-based peptides in a multiple antigenic peptide construct (MAP-3 and MAP-4) appeared to adjuvant protective immune responses induced by the TPX peptide in a MAP form. Production of TPX MAP-specific IgG1 serum antibodies, and increase in lung interleukin-1 (IL-1), uric acid, and reactive oxygen species (ROS) content were associated with significant (P < 0.05) 50 % reduction in recovery of lung-stage larvae. Increase in lung triglycerides and cholesterol levels appeared to provide the surviving worms with nutrients necessary for a stout double lipid bilayer barrier at the parasite-host interface. Surviving worms-released products elicited memory responses to the MAP-3 immunogen, including production of specific IgG1 antibodies and increase in liver IL-33 and ROS. Reduction in challenge worm burden recorded 45 days post infection did not exceed 48 % associated with no differences in parasite egg counts in the host liver and small intestine compared to unimmunized adjuvant control mice. Alum adjuvant assisted the second peptide, MAP-4, in production of IgG1, IgG2a, IgG2b and IgA specific antibodies and increase in liver ROS, but with no protective potential, raising doubt about the necessity of adjuvant addition. Accordingly, different vaccine formulas containing TPX MAP and 1, 2 or 3 cysteine peptidases-derived peptides with or without alum were used to immunize parallel groups of mice. Compared to unimmunized control mice, significant (P < 0.05 to < 0.005) 22 to 54 % reduction in worm burden was recorded in the different groups associated with insignificant changes in parasite egg output. The results together indicated that a schistosomiasis vaccine able to entirely prevent disease and halt its transmission still remains elusive.
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Affiliation(s)
- Hatem Tallima
- Zoology Department, Faculty of Science, Cairo University, Giza 12613, Egypt; Department of Chemistry, School of Sciences and Engineering, American University in Cairo, New Cairo 11835, Cairo, Egypt.
| | - Menerva M Tadros
- Department of Parasitology, Theodore Bilharz Research Institute, Warrak El-Hadar, Imbaba, Giza 12411, Egypt
| | - Rashika El Ridi
- Zoology Department, Faculty of Science, Cairo University, Giza 12613, Egypt
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Coffeng LE, Graham M, Browning R, Kura K, Diggle PJ, Denwood M, Medley GF, Anderson RM, de Vlas SJ. Improving the Cost-efficiency of Preventive Chemotherapy: Impact of New Diagnostics on Stopping Decisions for Control of Schistosomiasis. Clin Infect Dis 2024; 78:S153-S159. [PMID: 38662699 PMCID: PMC11045014 DOI: 10.1093/cid/ciae020] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Control of schistosomiasis (SCH) relies on the regular distribution of preventive chemotherapy (PC) over many years. For the sake of sustainable SCH control, a decision must be made at some stage to scale down or stop PC. These "stopping decisions" are based on population surveys that assess whether infection levels are sufficiently low. However, the limited sensitivity of the currently used diagnostic (Kato-Katz [KK]) to detect low-intensity infections is a concern. Therefore, the use of new, more sensitive, molecular diagnostics has been proposed. METHODS Through statistical analysis of Schistosoma mansoni egg counts collected from Burundi and a simulation study using an established transmission model for schistosomiasis, we investigated the extent to which more sensitive diagnostics can improve decision making regarding stopping or continuing PC for the control of S. mansoni. RESULTS We found that KK-based strategies perform reasonably well for determining when to stop PC at a local scale. Use of more sensitive diagnostics leads to a marginally improved health impact (person-years lived with heavy infection) and comes at a cost of continuing PC for longer (up to around 3 years), unless the decision threshold for stopping PC is adapted upward. However, if this threshold is set too high, PC may be stopped prematurely, resulting in a rebound of infection levels and disease burden (+45% person-years of heavy infection). CONCLUSIONS We conclude that the potential value of more sensitive diagnostics lies more in the reduction of survey-related costs than in the direct health impact of improved parasite control.
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Affiliation(s)
- Luc E Coffeng
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, The Netherlands
| | - Matthew Graham
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford
| | | | - Klodeta Kura
- London Centre for Neglected Tropical Disease Research, School of Public Health, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London
| | - Peter J Diggle
- Centre for Health Informatics, Computing, and Statistics, Lancaster University Medical School, United Kingdom
| | - Matthew Denwood
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Graham F Medley
- Department of Global Health and Development, Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, School of Public Health, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London
| | - Sake J de Vlas
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, The Netherlands
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Kura K, Mutono N, Basáñez MG, Collyer BS, Coffeng LE, Thumbi SM, Anderson RM. How Does Treatment Coverage and Proportion Never Treated Influence the Success of Schistosoma mansoni Elimination as a Public Health Problem by 2030? Clin Infect Dis 2024; 78:S126-S130. [PMID: 38662698 PMCID: PMC11045018 DOI: 10.1093/cid/ciae074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND The 2030 target for schistosomiasis is elimination as a public health problem (EPHP), achieved when the prevalence of heavy-intensity infection among school-aged children (SAC) reduces to <1%. To achieve this, the new World Health Organization guidelines recommend a broader target of population to include pre-SAC and adults. However, the probability of achieving EPHP should be expected to depend on patterns in repeated uptake of mass drug administration by individuals. METHODS We employed 2 individual-based stochastic models to evaluate the impact of school-based and community-wide treatment and calculated the number of rounds required to achieve EPHP for Schistosoma mansoni by considering various levels of the population never treated (NT). We also considered 2 age-intensity profiles, corresponding to a low and high burden of infection in adults. RESULTS The number of rounds needed to achieve this target depends on the baseline prevalence and the coverage used. For low- and moderate-transmission areas, EPHP can be achieved within 7 years if NT ≤10% and NT <5%, respectively. In high-transmission areas, community-wide treatment with NT <1% is required to achieve EPHP. CONCLUSIONS The higher the intensity of transmission, and the lower the treatment coverage, the lower the acceptable value of NT becomes. Using more efficacious treatment regimens would permit NT values to be marginally higher. A balance between target treatment coverage and NT values may be an adequate treatment strategy depending on the epidemiological setting, but striving to increase coverage and/or minimize NT can shorten program duration.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Nyamai Mutono
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Benjamin S Collyer
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
| | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center, University Medical Center Rotterdam, The Netherlands
| | - S M Thumbi
- Centre for Epidemiological Modelling and Analysis, University of Nairobi, Kenya
- Paul G. Allen School for Global Health, Washington State University, Pullman
- Institute of Immunology and Infection Research, University of Edinburgh, United Kingdom
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London
- Medical Research Council Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, United Kingdom
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Frempong NA, Ahiabor C, Anyan WK, Mama A, Kusi KA, Ofori MF, Adu B, Debrah AY, Anang AK, Ndam NT, Courtin D. Malaria, Urogenital Schistosomiasis, and Anaemia in Pregnant Ghanaian Women. J Parasitol Res 2023; 2023:7500676. [PMID: 37808169 PMCID: PMC10558271 DOI: 10.1155/2023/7500676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/03/2023] [Accepted: 09/08/2023] [Indexed: 10/10/2023] Open
Abstract
Background Anaemia is common in sub-Saharan Africa, and parasitic infections could worsen its burden during pregnancy. Moreover, women become susceptible to malaria during pregnancy. We investigated Plasmodium falciparum (P. falciparum) and Schistosoma haematobium (S. haematobium) infections and determined their association with anaemia during pregnancy. Methods A cross-sectional study involving 707 pregnant women attending antenatal care visits (ANC) and 446 at delivery was conducted in Battor and Adidome hospitals. Pregnant women were screened by microscopy and qPCR for P. falciparum and S. haematobium infections. Haemoglobin (Hb) levels were determined, and most participants received intermittent preventive treatment during pregnancy (IPTp) during ANC till delivery. Regression analyses were performed for associations between parasite infection and anaemia. Results P. falciparum microscopy prevalence at ANC and delivery was 8% and 2%, respectively, and by PCR 24% at ANC and 12% at delivery. Anaemia prevalence at ANC was 52% and 49% at delivery. There was an increased risk of anaemia with P. falciparum infection (aOR = 1.92; p = 0.04). IPTp (p = 0.003) and age (p = 0.004) were associated with increased Hb levels at delivery. S. haematobium prevalence by microscopy was 4% at ANC and 2% at delivery. No significant correlation between S. haematobium and Hb levels was observed (coef. = -0.62 g/dl; p = 0.07). Conclusion High anaemia prevalence was observed during pregnancy, and P. falciparum infection was associated with anaemia at ANC. Low S. haematobium prevalence could be attributed to previous praziquantel treatment during mass drug administration. Routine diagnosis and treatment of S. haematobium infections in endemic areas could be initiated to reduce schistosomiasis during pregnancy.
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Affiliation(s)
- Naa Adjeley Frempong
- Clinical Microbiology Department, Kwame Nkrumah University of Science and Technology, Ghana
- Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Charity Ahiabor
- Science Laboratory Technology, Accra Technical University, Ghana
| | - William K. Anyan
- Parasitology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Atikatou Mama
- Inserm U 1016, Institut Cochin, Université de Paris, 75014, France
| | - Kwadwo Asamoah Kusi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Michael F. Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Bright Adu
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Ghana
| | - Alex Yaw Debrah
- Faculty of Health Sciences, Kwame Nkrumah University of Science and Technology, Ghana
| | - Abraham K. Anang
- Institute of Environment and Sanitation Studies(IESS), University of Ghana, Legon, Ghana
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Mazigo HD, Samson A, Lambert VJ, Kosia AL, Ngoma DD, Murphy R, Kabole FM, Matungwa DJ. Healthcare Workers’ Low Knowledge of Female Genital Schistosomiasis and Proposed Interventions to Prevent, Control, and Manage the Disease in Zanzibar. Int J Public Health 2022; 67:1604767. [PMID: 36188750 PMCID: PMC9520356 DOI: 10.3389/ijph.2022.1604767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Objectives: This study was conducted to explore healthcare workers’ knowledge of female genital schistosomiasis (FGS) and describe proposed interventions to raise awareness about FGS and strengthen healthcare facilities’ capacity to manage FGS cases.Methods: We conducted four cross-sectional focus group discussions and 16 key informant interviews with purposively selected healthcare workers in Zanzibar. Discussions and interviews were digitally recorded, transcribed, and analyzed using NVivo software.Results: Most participants had limited or no knowledge of FGS and lacked skills for managing it. They confused FGS with urogenital schistosomiasis and thought it was sexually transmitted. A few participants knew about FGS and associated it with Human Immunodeficiency Virus (HIV), ectopic pregnancy, cervical cancer, and infertility. To prevent and control FGS, participants proposed interventions targeting communities (including community-based health education) and the healthcare system (including training healthcare workers on FGS).Conclusion: Healthcare workers lacked knowledge of and skills for managing FGS. Besides, healthcare facilities had no diagnostic capacity to manage FGS. Along with on-going interventions to break S. haematobium transmission and eventually eliminate urogenital schistosomiasis in Zanzibar, we recommend training healthcare workers on FGS and equip healthcare facilities with medical equipment and supplies for managing FGS.
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Affiliation(s)
- Humphrey D. Mazigo
- Department of Parasitology and Entomology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Anna Samson
- Department of Behavioral Sciences, School of Public Health, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Valencia J. Lambert
- Center for Global Health, Weill Cornell Medicine, New York, NY, United States
| | - Agnes L. Kosia
- School of Nursing, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Deogratias D. Ngoma
- Accelerating the Sustainable Control and Elimination of Neglected Tropical Diseases, Crown Agents, London, United Kingdom
| | | | | | - Dunstan J. Matungwa
- Department of Sexual and Reproductive Health, National Institute for Medical Research, Mwanza, Tanzania
- Department of Anthropology, School of Arts and Sciences, Rutgers University, New Brunswick, NJ, United States
- *Correspondence: Dunstan J. Matungwa,
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Díaz AV, Lambert S, Neves MI, Borlase A, Léger E, Diouf ND, Sène M, Webster JP, Walker M. Modelling livestock test-and-treat: A novel One Health strategy to control schistosomiasis and mitigate drug resistance. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.893066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schistosomiasis, a neglected tropical disease, is a widespread chronic helminthiasis reported in 78 countries, predominantly those within sub-Saharan Africa, as well as Latin America, Asia, and most recently, even Europe. Species of the causative blood fluke infect not only humans but also animals, and hybrids between previously assumed human-specific and animal-specific schistosomes are being increasingly reported. Existing control programs across Africa focus on humans and rely heavily on mass drug administration of praziquantel, the sole drug available against schistosomiasis. Praziquantel is safe and highly efficacious but could become ineffective if resistance emerges. To reach the revised World Health Organization goal of elimination of schistosomiasis as a public health problem, and interruption of transmission within selected regions, by 2030, new consideration of the role of animal reservoirs in human transmission in general, and whether to also treat livestock with praziquantel in particular, has been raised. However, whilst there are no dedicated control programs targeting animals outside of Asia, there are emerging reports of the use and misuse of praziquantel in livestock across Africa. Therefore, to effectively treat livestock in Africa and to help mitigate against the potential evolution of praziquantel resistance, structured control strategies are required. Here, using a transmission modelling approach, we evaluate the potential effectiveness of a theoretical test-and-treat (TnT) strategy to control bovine schistosomiasis using a currently available point-of-care diagnostic test (developed for human use) to detect circulating cathodic antigen (POC-CCA). We show that implementing TnT at herd-level from 2022 to 2030 could be highly effective in suppressing infection in cattle and even, in lower prevalence settings, reaching nominal ‘elimination’ targets. We highlight the importance of enhancing the specificity of POC-CCA for use in livestock to avoid unnecessary treatments and discuss the outstanding challenges associated with implementing TnT as part of a holistic One Health approach to tackling human and animal schistosomiasis.
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Johari NA, Annuzaili DA, El-Talabawy HF, Ba-Break M, Al-Mekhlafi AM, Al-Eryani S, Alkohlani AA, Gabrielli AF, Ben-Ismail R, Alhaidari S, Muaydh A, Alshami R, Al Gunaid M, Hamed A, Kamel N, Palacio K, Fleming F, French MD. National mapping of schistosomiasis, soil-transmitted helminthiasis and anaemia in Yemen: Towards better national control and elimination. PLoS Negl Trop Dis 2022; 16:e0010092. [PMID: 35333859 PMCID: PMC8986123 DOI: 10.1371/journal.pntd.0010092] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 04/06/2022] [Accepted: 02/17/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis (SCH) and soil-transmitted helminthiasis (STH) are known to be endemic in Yemen. However, the distribution of both diseases had not previously been assessed by a well-structured national mapping study covering all governorates. The main aim of this study was, therefore, to map the prevalence of SCH and STH in Yemen in order to better inform implementation of effective national control and elimination interventions. The assessment of the distribution of anaemia was also included as a well-known consequence of infection with both SCH and STH. Secondarily, the study aimed to provide a broad indication of the impact of large-scale treatment on the distribution of infection. METHODOLOGY AND PRINCIPAL FINDINGS To achive these aims, 80,432 children (10-14 years old) from 2,664 schools in 332 of Yemen's 333 districts were included, in 2014, into this national cross-sectional survey. Countrywide, 63.3% (210/332) and 75.6% (251/332) of districts were found to be endemic for SCH and STH respectively. More districts were affected by intestinal than urogenital SCH (54.2% and 31.6% respectively). SCH infection was mostly mild and moderate, with no districts reporting high infection. One quarter (24.4%) of Yemeni districts had high or moderate levels of Ascaris lumbricoides infection. Infection with Trichuris trichiura was the second most common STH (44.9% of districts infected) after A. lumbricoides (68.1%). Hookworm was the least prevalent STH (9.0%). Anaemia was prevalent in 96.4% of districts; it represented a severe public health problem (prevalence ≥ 40%) in 26.5% of districts, and a mild to moderate problem in two thirds of the districts (33.7% and 36.1% respectively). CONCLUSION This study provided the first comprehensive mapping of SCH, STH, and anaemia across the country. This formed the basis for evaluating and continuing the national control and elimination programme for these neglected tropical diseases in Yemen.
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Affiliation(s)
- Nur Alia Johari
- Schistosomiasis Control Initiative Foundation, London, United Kingdom
| | | | - Hani Farouk El-Talabawy
- Regional Office for the Eastern Mediterranean, Department of Information, Evidence and Research, Department of Communicable Diseases, World Health Organization, Cairo, Egypt
| | - Maryam Ba-Break
- Nuffield Centre for International Health and Development, University of Leeds, Leeds, United Kingdom
| | - Abdulsalam M. Al-Mekhlafi
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | - Samira Al-Eryani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana’a University, Sana’a, Yemen
| | | | - Albis Francesco Gabrielli
- Regional Office for the Eastern Mediterranean, Department of Communicable Diseases, World Health Organization, Cairo, Egypt
| | - Riadh Ben-Ismail
- Regional Office for the Eastern Mediterranean, Department of Communicable Diseases, World Health Organization, Cairo, Egypt
| | - Sami Alhaidari
- The National Schistosomiasis Control Programme (NSCP), Department of Primary Health Care, Ministry of Public Health and Population, Sana’a, Yemen
| | - Adel Muaydh
- The National Schistosomiasis Control Programme (NSCP), Department of Primary Health Care, Ministry of Public Health and Population, Sana’a, Yemen
| | - Rasheed Alshami
- The National Schistosomiasis Control Programme (NSCP), Department of Primary Health Care, Ministry of Public Health and Population, Sana’a, Yemen
| | - Magid Al Gunaid
- The National Schistosomiasis Control Programme (NSCP), Department of Primary Health Care, Ministry of Public Health and Population, Sana’a, Yemen
| | - Alaa Hamed
- The World Bank, Washington D.C, United States of America
| | - Nehad Kamel
- The World Bank, Washington D.C, United States of America
| | - Karen Palacio
- The End Fund, New York, New York, United States of America
| | - Fiona Fleming
- Schistosomiasis Control Initiative Foundation, London, United Kingdom
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Visclosky T, Hashikawa A, Kroner E. Discovery of a Hidden Schistosomiasis Endemic in the Salamat Region of Chad, Africa. GLOBAL HEALTH: SCIENCE AND PRACTICE 2022; 10:GHSP-D-20-00703. [PMID: 35294372 PMCID: PMC8885350 DOI: 10.9745/ghsp-d-20-00703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 01/05/2022] [Indexed: 11/15/2022]
Affiliation(s)
- Timothy Visclosky
- Department of Emergency Medicine, University of Michigan, Ann Arbor, MI, USA.
| | - Andrew Hashikawa
- Department of Emergency Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Eric Kroner
- The Evangelical Alliance Mission, Grapevine, TX, USA
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Fergus CA, Ozunga B, Okumu N, Parker M, Kamurari S, Allen T. Shifting the dynamics: implementation of locally driven, mixed-methods modelling to inform schistosomiasis control and elimination activities. BMJ Glob Health 2022; 7:e007113. [PMID: 35110273 PMCID: PMC8811568 DOI: 10.1136/bmjgh-2021-007113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 01/03/2022] [Indexed: 11/27/2022] Open
Abstract
INTRODUCTION The integration of more diverse perspectives into the development of evidence for decision-making has been elusive, despite years of rhetoric to the contrary. This has led to cycles of population-based health interventions which have not delivered the promised results. The WHO most recently set a target for schistosomiasis elimination by 2030 and called for cross-cutting approaches to be driven by endemic countries themselves. The extent to which elimination is feasible within the time frame has been a subject of debate. METHODS Systems maps were developed through participatory modelling activities with individuals working on schistosomiasis control and elimination activities from the village through national levels in Uganda. These maps were first synthesised, then used to frame the form and content of subsequent mathematical modelling activities, and finally explicitly informed model parameter specifications for simulations, using the open-source SCHISTOX model, driven by the participants. RESULTS Based on the outputs of the participatory modelling, the simulation activities centred around reductions in water contact. The results of the simulations showed that mass drug administration, at either the current or target levels of coverage, combined with water contact reduction activities, achieved morbidity control in high prevalence Schistosoma mansoni settings, while both morbidity control and elimination were achieved in high prevalence S. haematobium settings within the 10-year time period. CONCLUSION The combination of participatory systems mapping and individual-based modelling was a rich strategy which explicitly integrated the perspectives of national and subnational policymakers and practitioners into the development of evidence. This strategy can serve as a method by which individuals who have not been traditionally included in modelling activities, and do not hold positions or work in traditional centres of power, may be heard and truly integrated into the development of evidence for decision-making in global health.
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Affiliation(s)
- Cristin Alexis Fergus
- Firoz Lalji Institute for Africa, LSE, London, UK
- Department of International Development, LSE, London, UK
| | - Bono Ozunga
- Vector Control Division, Republic of Uganda Ministry of Health, Mayuge, Uganda
| | - Noah Okumu
- Vector Control Division, Republic of Uganda Ministry of Health, Pakwach, Uganda
| | - Melissa Parker
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Tim Allen
- Firoz Lalji Institute for Africa, LSE, London, UK
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11
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Kura K, Hardwick RJ, Truscott JE, Anderson RM. What is the impact of acquired immunity on the transmission of schistosomiasis and the efficacy of current and planned mass drug administration programmes? PLoS Negl Trop Dis 2021; 15:e0009946. [PMID: 34851952 PMCID: PMC8635407 DOI: 10.1371/journal.pntd.0009946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 10/23/2021] [Indexed: 11/18/2022] Open
Abstract
Schistosomiasis causes severe morbidity in many countries with endemic infection with the schistosome digenean parasites in Africa and Asia. To control and eliminate the disease resulting from infection, regular mass drug administration (MDA) is used, with a focus on school-aged children (SAC; 5-14 years of age). In some high transmission settings, the World Health Organization (WHO) also recommends the inclusion of at-risk adults in MDA treatment programmes. The question of whether ecology (age-dependant exposure) or immunity (resistance to reinfection), or some combination of both, determines the form of observed convex age-intensity profile is still unresolved, but there is a growing body of evidence that the human hosts acquire some partial level of immunity after a long period of repeated exposure to infection. In the majority of past research modelling schistosome transmission and the impact of MDA programmes, the effect of acquired immunity has not been taken into account. Past work has been based on the assumption that age-related contact rates generate convex horizontal age-intensity profiles. In this paper, we use an individual based stochastic model of transmission and MDA impact to explore the effect of acquired immunity in defined MDA programmes. Compared with scenarios with no immunity, we find that acquired immunity makes the MDA programme less effective with a slower decrease in the prevalence of infection. Therefore, the time to achieve morbidity control and elimination as a public health problem is longer than predicted by models with just age-related exposure and no build-up of immunity. The level of impact depends on the baseline prevalence prior to treatment (the magnitude of the basic reproductive number R0) and the treatment frequency, among other factors. We find that immunity has a larger impact within moderate to high transmission settings such that it is very unlikely to achieve morbidity and transmission control employing current MDA programmes.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, London, United Kingdom
| | - Robert J. Hardwick
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, London, United Kingdom
- The DeWorm3 Project, The Natural History Museum of London, London, United Kingdom
| | - James E. Truscott
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, London, United Kingdom
- The DeWorm3 Project, The Natural History Museum of London, London, United Kingdom
| | - Roy M. Anderson
- London Centre for Neglected Tropical Disease Research, London, United Kingdom
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary’s Campus, Imperial College London, London, United Kingdom
- MRC Centre for Global Infectious Disease Analysis, London, United Kingdom
- The DeWorm3 Project, The Natural History Museum of London, London, United Kingdom
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12
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Metcalf CJE, Andriamandimby SF, Baker RE, Glennon EE, Hampson K, Hollingsworth TD, Klepac P, Wesolowski A. Challenges in evaluating risks and policy options around endemic establishment or elimination of novel pathogens. Epidemics 2021; 37:100507. [PMID: 34823222 PMCID: PMC7612525 DOI: 10.1016/j.epidem.2021.100507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/20/2021] [Accepted: 10/06/2021] [Indexed: 11/12/2022] Open
Abstract
When a novel pathogen emerges there may be opportunities to eliminate transmission - locally or globally - whilst case numbers are low. However, the effort required to push a disease to elimination may come at a vast cost at a time when uncertainty is high. Models currently inform policy discussions on this question, but there are a number of open challenges, particularly given unknown aspects of the pathogen biology, the effectiveness and feasibility of interventions, and the intersecting political, economic, sociological and behavioural complexities for a novel pathogen. In this overview, we detail how models might identify directions for better leveraging or expanding the scope of data available on the pathogen trajectory, for bounding the theoretical context of emergence relative to prospects for elimination, and for framing the larger economic, behavioural and social context that will influence policy decisions and the pathogen’s outcome.
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Affiliation(s)
- C Jessica E Metcalf
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA; Princeton School of Public and International Affairs, Princeton University, Princeton, USA.
| | | | - Rachel E Baker
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA; Princeton High Meadows Environmental Institute, Princeton University, Princeton, NJ, USA
| | - Emma E Glennon
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Katie Hampson
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, UK
| | - Petra Klepac
- London School of Hygiene and Tropical Medicine, London, UK
| | - Amy Wesolowski
- Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
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13
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Novel tools and strategies for breaking schistosomiasis transmission: study protocol for an intervention study. BMC Infect Dis 2021; 21:1024. [PMID: 34592960 PMCID: PMC8482678 DOI: 10.1186/s12879-021-06620-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Background Global elimination of schistosomiasis as a public health problem is set as target in the new World Health Organization’s Neglected Tropical Diseases Roadmap for 2030. Due to a long history of interventions, the Zanzibar islands of Tanzania have reached this goal since 2017. However, challenges occur on the last mile towards interruption of transmission. Our study will investigate new tools and strategies for breaking schistosomiasis transmission. Methods The study is designed as an intervention study, documented through repeated cross-sectional surveys (2020–2024). The primary endpoint will be the sensitivity of a surveillance-response approach to detect and react to outbreaks of urogenital schistosomiasis over three years of implementation. The surveys and multi-disciplinary interventions will be implemented in 20 communities in the north of Pemba island. In low-prevalence areas, surveillance-response will consist of active, passive and reactive case detection, treatment of positive individuals, and focal snail control. In hotspot areas, mass drug administration, snail control and behaviour change interventions will be implemented. Parasitological cross-sectional surveys in 20 communities and their main primary schools will serve to adapt the intervention approach annually and to monitor the performance of the surveillance-response approach and impact of interventions. Schistosoma haematobium infections will be diagnosed using reagent strips and urine filtration microscopy, and by exploring novel point-of-care diagnostic tests. Discussion Our study will shed light on the field applicability and performance of novel adaptive intervention strategies, and standard and new diagnostic tools for schistosomiasis elimination. The evidence and experiences generated by micro-mapping of S. haematobium infections at community level, micro-targeting of new adaptive intervention approaches, and application of novel diagnostic tools can guide future strategic plans for schistosomiasis elimination in Zanzibar and inform other countries aiming for interruption of transmission. Trial registration ISRCTN, ISCRCTN91431493. Registered 11 February 2020, https://www.isrctn.com/ISRCTN91431493
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14
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Turner HC, Stolk WA, Solomon AW, King JD, Montresor A, Molyneux DH, Toor J. Are current preventive chemotherapy strategies for controlling and eliminating neglected tropical diseases cost-effective? BMJ Glob Health 2021; 6:bmjgh-2021-005456. [PMID: 34385158 PMCID: PMC8362715 DOI: 10.1136/bmjgh-2021-005456] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/23/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
Neglected tropical diseases (NTDs) remain a significant cause of morbidity and mortality in many low-income and middle-income countries. Several NTDs, namely lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases (STH) and trachoma, are predominantly controlled by preventive chemotherapy (or mass drug administration), following recommendations set by the WHO. Over one billion people are now treated for NTDs with this strategy per year. However, further investment and increased domestic healthcare spending are urgently needed to continue these programmes. Consequently, it is vital that the cost-effectiveness of preventive chemotherapy is understood. We analyse the current estimates on the cost per disability-adjusted life year (DALY) of the preventive chemotherapy strategies predominantly used for these diseases and identify key evidence gaps that require further research. Overall, the reported estimates show that preventive chemotherapy is generally cost-effective, supporting WHO recommendations. More specifically, the cost per DALY averted estimates relating to community-wide preventive chemotherapy for lymphatic filariasis and onchocerciasis were particularly favourable when compared with other public health interventions. Cost per DALY averted estimates of school-based preventive chemotherapy for schistosomiasis and STH were also generally favourable but more variable. Notably, the broader socioeconomic benefits are likely not being fully captured by the DALYs averted metric. No estimates of cost per DALY averted relating to community-wide mass antibiotic treatment for trachoma were found, highlighting the need for further research. These findings are important for informing global health policy and support the need for continuing NTD control and elimination efforts.
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Affiliation(s)
- Hugo C Turner
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK .,Oxford University Clinical Research Unit, Wellcome Africa Asia Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Wilma A Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Jonathan D King
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Antonio Montresor
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - David H Molyneux
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Jaspreet Toor
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London, UK,Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
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15
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Ayabina D, Kura K, Toor J, Graham M, Anderson RM, Hollingsworth TD. Maintaining Low Prevalence of Schistosoma mansoni: Modeling the Effect of Less Frequent Treatment. Clin Infect Dis 2021; 72:S140-S145. [PMID: 33909064 PMCID: PMC8201569 DOI: 10.1093/cid/ciab246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The World Health Organization previously set goals of controlling morbidity due to schistosomiasis by 2020 and attaining elimination as a public health problem (EPHP) by 2025 (now adjusted to 2030 in the new neglected tropical diseases roadmap). As these milestones are reached, it is important that programs reassess their treatment strategies to either maintain these goals or progress from morbidity control to EPHP and ultimately to interruption of transmission. In this study, we consider different mass drug administration (MDA) strategies to maintain the goals. METHODS We used 2 independently developed, individual-based stochastic models of schistosomiasis transmission to assess the optimal treatment strategy of a multiyear program to maintain the morbidity control and the EPHP goals. RESULTS We found that, in moderate-prevalence settings, once the morbidity control and EPHP goals are reached it may be possible to maintain the goals using less frequent MDAs than those that are required to achieve the goals. On the other hand, in some high-transmission settings, if control efforts are reduced after achieving the goals, particularly the morbidity control goal, there is a high chance of recrudescence. CONCLUSIONS To reduce the risk of recrudescence after the goals are achieved, programs have to re-evaluate their strategies and decide to either maintain these goals with reduced efforts where feasible or continue with at least the same efforts required to reach the goals.
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Affiliation(s)
- Diepreye Ayabina
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Klodeta Kura
- London Centre for Neglected Tropical Disease Research, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom.,MRC Centre for Global Infectious Disease Analysis, London,United Kingdom
| | - Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,MRC Centre for Global Infectious Disease Analysis, London,United Kingdom.,Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, London, United Kingdom
| | - Matt Graham
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, United Kingdom.,MRC Centre for Global Infectious Disease Analysis, London,United Kingdom.,The DeWorm3 Project, The Natural History Museum of London, London, United Kingdom
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
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16
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Minter A, Pellis L, Medley GF, Hollingsworth TD. What Can Modeling Tell Us About Sustainable End Points for Neglected Tropical Diseases? Clin Infect Dis 2021; 72:S129-S133. [PMID: 33905477 PMCID: PMC8201563 DOI: 10.1093/cid/ciab188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
As programs move closer toward the World Health Organization (WHO) goals of reduction in morbidity, elimination as a public health problem or elimination of transmission, countries will be faced with planning the next stages of surveillance and control in low prevalence settings. Mathematical models of neglected tropical diseases (NTDs) will need to go beyond predicting the effect of different treatment programs on these goals and on to predicting whether the gains can be sustained. One of the most important challenges will be identifying the policy goal and the right constraints on interventions and surveillance over the long term, as a single policy option will not achieve all aims—for example, minimizing morbidity and minimizing costs cannot both be achieved. As NTDs move toward 2030 and beyond, more nuanced intervention choices will be informed by quantitative analyses which are adapted to national context.
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Affiliation(s)
- Amanda Minter
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Lorenzo Pellis
- Department of Mathematics, University of Manchester, Manchester, United Kingdom.,The Alan Turing Institute, London, United Kingdom
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
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17
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Kura K, Ayabina D, Toor J, Hollingsworth TD, Anderson RM. Disruptions to schistosomiasis programmes due to COVID-19: an analysis of potential impact and mitigation strategies. Trans R Soc Trop Med Hyg 2021; 115:236-244. [PMID: 33515038 PMCID: PMC7928593 DOI: 10.1093/trstmh/traa202] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/28/2020] [Accepted: 01/03/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The 2030 goal for schistosomiasis is elimination as a public health problem (EPHP), with mass drug administration (MDA) of praziquantel to school-age children (SAC) as a central pillar of the strategy. However, due to coronavirus disease 2019, many mass treatment campaigns for schistosomiasis have been halted, with uncertain implications for the programmes. METHODS We use mathematical modelling to explore how postponement of MDA and various mitigation strategies affect achievement of the EPHP goal for Schistosoma mansoni and S. haematobium. RESULTS For both S. mansoni and S. haematobium in moderate- and some high-prevalence settings, the disruption may delay the goal by up to 2 y. In some high-prevalence settings, EPHP is not achievable with current strategies and so the disruption will not impact this. Here, increasing SAC coverage and treating adults can achieve the goal. The impact of MDA disruption and the appropriate mitigation strategy varies according to the baseline prevalence prior to treatment, the burden of infection in adults and the stage of the programme. CONCLUSIONS Schistosomiasis MDA programmes in medium- and high-prevalence areas should restart as soon as is feasible and mitigation strategies may be required in some settings.
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Affiliation(s)
- Klodeta Kura
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK.,MRC Centre for Global Infectious Disease Analysis
| | - Diepreye Ayabina
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK
| | - Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford OX3 7LF, UK
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, London, UK.,MRC Centre for Global Infectious Disease Analysis.,DeWorm3 Project, Natural History Museum of London, London, UK
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18
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Hollingsworth TD, Mwinzi P, Vasconcelos A, de Vlas SJ. Evaluating the potential impact of interruptions to neglected tropical disease programmes due to COVID-19. Trans R Soc Trop Med Hyg 2021; 115:201-204. [PMID: 33693894 PMCID: PMC7946803 DOI: 10.1093/trstmh/trab023] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/11/2021] [Indexed: 01/05/2023] Open
Affiliation(s)
- T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Old Road Campus, Headington, Oxford OX3 7LF, UK
| | - Pauline Mwinzi
- Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN), World Health Organization Regional Office for Africa, P.O.BOX 06 Cité du Djoué Brazzaville, Congo
| | - Andreia Vasconcelos
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Old Road Campus, Headington, Oxford OX3 7LF, UK
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, P.O. Box 2040, 3000 CA Rotterdam, the Netherlands
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19
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Toor J, Coffeng LE, Hamley JID, Fronterre C, Prada JM, Castaño MS, Davis EL, Godwin W, Vasconcelos A, Medley GF, Hollingsworth TD. When, Who, and How to Sample: Designing Practical Surveillance for 7 Neglected Tropical Diseases as We Approach Elimination. J Infect Dis 2021; 221:S499-S502. [PMID: 32529261 PMCID: PMC7289548 DOI: 10.1093/infdis/jiaa198] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
As neglected tropical disease programs look to consolidate the successes of moving towards elimination, we need to understand the dynamics of transmission at low prevalence to inform surveillance strategies for detecting elimination and resurgence. In this special collection, modelling insights are used to highlight drivers of local elimination, evaluate strategies for detecting resurgence, and show the importance of rational spatial sampling schemes for several neglected tropical diseases (specifically schistosomiasis, soil-transmitted helminths, lymphatic filariasis, trachoma, onchocerciasis, visceral leishmaniasis, and gambiense sleeping sickness).
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Affiliation(s)
- Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Luc E Coffeng
- Department of Public Health, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Jonathan I D Hamley
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom.,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Claudio Fronterre
- Centre for Health Informatics, Computing, and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Joaquin M Prada
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - M Soledad Castaño
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Emma L Davis
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - William Godwin
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA
| | - Andreia Vasconcelos
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
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20
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Impact of seven years of mass drug administration and recrudescence of Schistosoma haematobium infections after one year of treatment gap in Zanzibar: Repeated cross-sectional studies. PLoS Negl Trop Dis 2021; 15:e0009127. [PMID: 33577601 PMCID: PMC7880478 DOI: 10.1371/journal.pntd.0009127] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/12/2021] [Indexed: 11/25/2022] Open
Abstract
Background Considerable progress towards the elimination of urogenital schistosomiasis was made by the Zanzibar Elimination of Schistosomiasis Transmission project from 2012 till 2016, when biannual praziquantel mass drug administration (MDA) alone or with additional snail control or behaviour change interventions were implemented. Annual MDA was continued in 2017 and 2018, but not in 2019, imposing a 16-month treatment gap. We monitored the Schistosoma haematobium prevalence from 2012 till 2020 and assessed recrudescence patterns with focus on 2020. Methodology Repeated cross-sectional surveys were conducted from 2011/12 till 2020 in 90 communities and 90 schools in Zanzibar. Annually, around 4,500 adults and up to 20,000 schoolchildren were surveyed. The S. haematobium prevalence was detected by urine filtration and reagent strips. In 2020, risk factors for infection were investigated using generalized estimated equation models. Principal findings In adults, the apparent S. haematobium prevalence was 3.9% in 2011 and 0.4% in 2020. In schoolchildren, the prevalence decreased from 6.6% in 2012 to 1.2% in 2019 with vicissitudes over the years. Prominent recrudescence of infection from 2.8% in 2019 to 9.1% (+225%) in 2020 was observed in 29 schools with historically moderate prevalences (≥10%). Compared with 2019, reinfection in 2020 was particularly striking in boys aged 9–16 years. Being male was a risk factor for infection in 2020 (adults: odds ratio (OR): 6.24, 95% confidence interval (95% CI): 1.96–19.60; schoolchildren: OR: 2.06, 95% CI: 1.52–2.78). Living near to a natural freshwater body significantly increased the odds of infection in adults (OR: 2.90, CI: 1.12–7.54). Conclusions/Significance After 11 rounds of MDA over 7 years and a 16-month treatment gap, the urogenital schistosomiasis prevalence considerably rebounded in hotspot areas. Future elimination efforts in Zanzibar should focus on re-intensifying MDA plus additional interventions in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted surveillance-response. Schistosomiasis is a neglected tropical disease caused by parasitic blood flukes of the genus Schistosoma. On the Zanzibar islands, United Republic of Tanzania, interventions to eliminate urogenital schistosomiasis commenced in 2012. From 2012 to 2016, the population was treated biannually with praziquantel and, additionally, some areas received mollusciciding against the intermediate host snail, or educational measures for behavior change. Mass drug administration (MDA) with praziquantel was continued annually in 2017 and 2018, but not in 2019. As a result of the interventions, the overall S. haematobium prevalence was reduced to 0.4% in adults and 3.4% in schoolchildren in 2020. However, in some areas, the MDA gap in 2019 resulted in a considerable rebound of infections. The recrudescence in 2020 was particularly striking for boys aged 9–16 years. In general, in 2020, male participants had higher odds of infection than females. Adults living near to a natural freshwater body also showed an increased risk of S. haematobium infection. Future elimination efforts in Zanzibar should focus on re-intensifying elimination interventions, including MDA, snail control and behavior change in hotspot areas. In low-prevalence areas, the strategy might be adapted from MDA to targeted interventions, such as surveillance-response.
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21
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Graham M, Ayabina D, Lucas TC, Collyer BS, Medley GF, Hollingsworth TD, Toor J. SCHISTOX: An individual based model for the epidemiology and control of schistosomiasis. Infect Dis Model 2021; 6:438-447. [PMID: 33665519 PMCID: PMC7897994 DOI: 10.1016/j.idm.2021.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 01/21/2021] [Indexed: 02/08/2023] Open
Abstract
A stochastic individual based model, SCHISTOX, has been developed for the study of schistosome transmission dynamics and the impact of control by mass drug administration. More novel aspects that can be investigated include individual level adherence and access to treatment, multiple communities, human sex population dynamics, and implementation of a potential vaccine. Many of the model parameters have been estimated within previous studies and have been shown to vary between communities, such as the age-specific contact rates governing the age profiles of infection. However, uncertainty remains as there are wide ranges for certain parameter values and a few remain relatively unknown. We analyse the model dynamics by parameterizing it with published parameter values. We also discuss the development of SCHISTOX in the form of a publicly available open-source GitHub repository. The next key development stage involves validating the model by calibrating to epidemiological data.
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Affiliation(s)
- Matthew Graham
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Diepreye Ayabina
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Tim Cd Lucas
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,Centre for Environment and Health, Imperial College London, London, United Kingdom
| | - Benjamin S Collyer
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Mary's Campus, Imperial College London, United Kingdom
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom
| | - Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, United Kingdom.,MRC Centre for Global Infectious Disease Analysis; and the Abdul Latif Jameel Institute for Disease and Emergency Analytics (J-IDEA), School of Public Health, Imperial College London, London, W2 1PG, United Kingdom
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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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