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Rayment Gomez S, Maddren R, Liyew EF, Chernet M, Anjulo U, Tamiru A, Tollera G, Tasew G, Mengistu B, Collyer B, Forbes K, Anderson R. Spatial heterogeneity in mass drug administration from a longitudinal epidemiological study assessing transmission interruption of soil transmitted helminths in the Wolaita zone of southern Ethiopia (Geshiyaro Project). PLoS Negl Trop Dis 2024; 18:e0011947. [PMID: 38330143 PMCID: PMC10880954 DOI: 10.1371/journal.pntd.0011947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 02/21/2024] [Accepted: 01/28/2024] [Indexed: 02/10/2024] Open
Abstract
OBJECTIVES Deworming programmes of soil-transmitted helminths are generally monitored and evaluated by aggregating drug coverage and infection levels at a district level. However, heterogeneity in drug coverage at finer spatial scales means indicators may remain above thresholds for elimination as a public health problem or of transmission in some areas. This paper aims to highlight the misleading information that aggregating data at larger spatial scales can have for programme decision making. METHODS Drug coverage data from the Geshiyaro project were compared at two spatial scales with reference to the World Health Organisation's targets. District (woreda) and village (kebele) level were compared. The association between infection levels and drug coverage was analysed by fitting a weighted least-squares function to the mean intensity of infection (eggs per gram of faeces) against drug coverage. RESULTS The data show clearly that when the evaluation of coverage is aggregated to the district level, information on heterogeneity at a finer spatial scale is lost. Infection intensity decreases significantly (p = 0.0023) with increasing drug coverage. CONCLUSION Aggregating data at large spatial scales can result in prematurely ceasing deworming, prompting rapid infection bounce-back. There is a strong need to define context-specific spatial scales for monitoring and evaluating intervention programmes.
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Affiliation(s)
- Santiago Rayment Gomez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
| | - Rosie Maddren
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
| | - Ewnetu Firdawek Liyew
- Bacterial, Parasitic and Zoonotic Disease Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Melkie Chernet
- Bacterial, Parasitic and Zoonotic Disease Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Ufaysa Anjulo
- Disease Prevention and Health Promotion Core Process, Ministry of Health, Wolaita, Ethiopia
| | - Adugna Tamiru
- Disease Prevention and Health Promotion Core Process, Ministry of Health, Wolaita, Ethiopia
| | - Getachew Tollera
- Bacterial, Parasitic and Zoonotic Disease Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Geremew Tasew
- Bacterial, Parasitic and Zoonotic Disease Research Directorate, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Birhan Mengistu
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
| | - Benjamin Collyer
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
| | - Kathryn Forbes
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
| | - Roy Anderson
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Faculty of Medicine, St Marys Campus, Imperial College London, London, United Kingdom
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Lim RM, Arme TM, Pedersen AB, Webster JP, Lamberton PHL. Defining schistosomiasis hotspots based on literature and shareholder interviews. Trends Parasitol 2023; 39:1032-1049. [PMID: 37806786 DOI: 10.1016/j.pt.2023.09.006] [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: 08/04/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 10/10/2023]
Abstract
The World Health Organization (WHO) recently proposed a new operational definition which designates communities with ≥10% prevalence of Schistosoma spp. infection as a persistent hotspot, when, after at least two rounds of high-coverage annual preventive chemotherapy, there is a lack of appropriate reduction. However, inconsistencies and challenges from both biological and operational perspectives remain, making the prescriptive use of this definition difficult. Here, we present a comprehensive analysis of the use of the term 'hotspot' across schistosomiasis research over time, including both literature searches and opinions from a range of stakeholders, to assess the utility and generalisability of the new WHO definition of a persistent hotspot. Importantly, we propose an updated definition based on our analyses.
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Affiliation(s)
- Rivka M Lim
- Institute of Evolution and Ecology, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK.
| | - Thomas M Arme
- School of Biodiversity, One Health and Veterinary Medicine, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Amy B Pedersen
- Institute of Evolution and Ecology, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
| | - Joanne P Webster
- Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Herts, UK
| | - Poppy H L Lamberton
- School of Biodiversity, One Health and Veterinary Medicine, Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
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Onkanga IO, Sang H, Hamilton R, Ondigo BN, Jaoko W, Odiere MR, Ganley-Leal L. CD193
(
CCR3
) expression by B cells correlates with reduced
IgE
production in paediatric schistosomiasis. Parasite Immunol 2023; 45:e12979. [PMID: 36971331 DOI: 10.1111/pim.12979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/21/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023]
Abstract
We demonstrate that CD193, the eotaxin receptor, is highly expressed on circulating B cells in paediatric schistosomiasis mansoni. CD193 plays a role in directing granulocytes into sites of allergic-like inflammation in the mucosa, but little is known about its functional significance on human B cells. We sought to characterize CD193 expression and its relationship with S. mansoni infection. We found that CD193+ B cells increased with the intensity of schistosome infection. In addition, a significant negative association was observed between CD193 expression by B cells and IgE production. Decreased IgE levels are generally associated with susceptibility to re-infection. B cell stimulation with eotaxin-1 increased CD193 levels whereas IL-4 led to a reduction. This was supported by plasma levels of eotaxin-1 correlating with CD193 levels on B cells and other cells. In contrast, CD193 expression was induced on naive B cells with a combination of IL-10 and schistosome antigens. Whereas T cells had a modest increase in CD193 expression, only B cell CD193 appeared functionally chemotactic to eotaxin-1. Thus, CD193+ B cells, which co-express CXCR5, may be enroute to sites with allergic-like inflammation, such as gastrointestinal follicles, or even to Th2 granulomas, which develop around parasite eggs. Overall, our results suggest that schistosome infection may promote CD193 expression and suppress IgE via IL-10 and other undefined mechanisms related to B cell trafficking. This study adds to our understanding of why young children may have poor immunity. Nonetheless, praziquantel treatment was shown to reduce percentages of circulating CD193+ B cells lending hope for future vaccine efforts.
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Affiliation(s)
- I O Onkanga
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- KAVI-Institute of Clinical Research, and Department of Medical Microbiology & Immunology, University of Nairobi, Nairobi, Kenya
| | - H Sang
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - R Hamilton
- Elegance Biotechnologies, LLC, Wayne, Pennsylvania, USA
| | - B N Ondigo
- Department of Biochemistry and Molecular Biology, Faculty of Science, Egerton University, Egerton, Kenya
| | - W Jaoko
- KAVI-Institute of Clinical Research, and Department of Medical Microbiology & Immunology, University of Nairobi, Nairobi, Kenya
| | - M R Odiere
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - L Ganley-Leal
- Elegance Biotechnologies, LLC, Wayne, Pennsylvania, USA
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Chanhanga N, Mindu T, Mogaka J, Chimbari M. The Impact of Targeted Treatment and Mass Drug Administration Delivery Strategies on the Prevalence and Intensity of Schistosomiasis in School Aged Children in Africa: A Systematic Review. Infect Drug Resist 2023; 16:2453-2466. [PMID: 37138838 PMCID: PMC10150034 DOI: 10.2147/idr.s395382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/16/2023] [Indexed: 05/05/2023] Open
Abstract
Schistosomiasis is a public health problem in more than 78 countries in the world. The disease is most prevalent among children than adults due to their high exposure to infectious water sources. Various interventions such as mass drug administration (MDA), snail control, safe water provision and health education have been implemented independently or jointly to control, reduce and ultimately eliminate Schistosomiasis. This scoping review focused on studies reporting the impact of different delivery strategies of targeted treatment and MDA on the prevalence and intensity of schistosomiasis infection in school aged children in Africa. The review focused on Schistosoma haematobium and Schistosoma mansoni species. A systematic search for eligible literature from peer-reviewed articles was done from Google Scholar, Medline, PubMed and EBSCO host databases. The search yielded twenty-seven peer-reviewed articles. All articles found reported a decrease in the prevalence of schistosomiasis infection. Five studies (18.5%) reported a prevalence change below 40%, eighteen studies (66.7%) reported a change between 40% and 80%, and four studies (14.8%) reported a change above 80%. The infection intensity post-treatment was varied: twenty-four studies reported a decrease, while two studies reported an increase. The review showed that the impact of targeted treatment on the prevalence and intensity of schistosomiasis depended on the frequency at which it was offered, complementary interventions, and its uptake by the target population. Targeted treatment can significantly control the infection burden, but cannot eliminate the disease. Constant MDA programs coupled with preventative and health promotional programs are required to reach the elimination stage.
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Affiliation(s)
- Nathan Chanhanga
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
| | - Tafadzwa Mindu
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
- Correspondence: Tafadzwa Mindu, Email
| | - John Mogaka
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
| | - Moses Chimbari
- School of Nursing and Public Health, University of KwaZulu Natal, Durban, South Africa
- Research and Innovation, Great Zimbabwe University, Masvingo, Zimbabwe
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5
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Expression of CD117 (c-Kit) on Circulating B Cells in Pediatric Schistosomiasis. Infect Immun 2022; 90:e0016022. [PMID: 35862720 PMCID: PMC9387214 DOI: 10.1128/iai.00160-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Few B cells express CD27, the primary marker for memory B cells, in pediatric schistosomiasis, suggesting B cell malfunction. This study further demonstrates unexpected high expression of CD117 on circulating B cells in children highly exposed to Schistosoma mansoni infectious larvae. CD117 is expressed by immature or lymphoma B cells, but not by mature, circulating cells. We therefore sought to define the significance of CD117 on blood B cells. We found that CD117-positive (CD117+) B cells increased with the intensity of schistosome infection. In addition, CD117 expression was reduced on CD23+ B cells previously shown to correlate with resistance to infection. Stimulation with a panel of cytokines demonstrated that CD117 levels were upregulated in response to a combination of interleukin 4 (IL-4) and stem cell factor (SCF), the ligand for CD117, whereas IL-2 led to a reduction. In addition, stimulation with SCF generally reduced B cell activation levels. Upon further investigation, it was established that multiple circulating cells expressed increased levels of CD117, including monocytes, neutrophils, and eosinophils, and expression levels correlated with that of B cells. Finally, we identified a population of large circulating cells with features of reticulocytes. Overall, our results suggest that hyperexposure to intravascular parasitic worms elicits immature cells from the bone marrow. Levels of SCF were shown to reduce as children began to transition through puberty. The study results pose an explanation for the inability of children to develop significant immunity to infection until after puberty.
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Senkwe MN, Berta KK, Yibi SM, Sube J, Bidali A, Abe A, Onyeze A, Ajo JPH, Pascale JR, Ndenzako F, Olu OO. Prevalence and factors associated with transmission of schistosomiasis in school-aged children in South Sudan: a cross-sectional study. Pan Afr Med J 2022; 42:2. [PMID: 36158934 PMCID: PMC9475048 DOI: 10.11604/pamj.supp.2022.42.1.34006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 05/25/2022] [Indexed: 11/11/2022] Open
Abstract
Introduction South Sudan is affected by a high burden of Neglected Tropical Diseases (NTDs). The country is very vulnerable to NTDs due to its favourable tropical climate and multiple risk factors. However, the distribution of the diseases and the populations at risk for the various NTDs is unknown. This paper described the distribution of schistosomiasis in 58 counties and 261 schools in South Sudan. Methods a descriptive quantitative cross-sectional study of schistosomiasis in 58 counties in 8 states of South Sudan recruited school-aged children. Using different laboratory techniques, the children were tested for Schistosoma mansoni (S. mansoni) and Schistosoma haematobium (S. haematobium). A quantitative descriptive statistical was performed to determine the prevalence rates and the endemicity of schistosomiasis among 13,286 school-aged children. Results the overall prevalence of S. mansoni and S. haematobium were 6.1% and 3.7% using Kato Katz and urine filtration concentration testing techniques. The highest state prevalence was reported in Western Equatoria for both S. mansoni (14.7%) and S. haematobium (7.3%). The age of the participants varied from 4 to 18 years; of these, children 10 to 12 years old had the highest prevalence of S. mansoni (6.8%) and S. haematobium (3.7%). The prevalence of S. mansoni (7% male vs 5% female) and S. haematobium (3.6% male vs 3.1% female) were higher in males than females. The likelihood of the prevalence of S. mansoni in males was 1.42 (95% CI:1.23, 1.64) higher than in females, while for S. haematobium, 1.36 (95% CI:1.12, 1.65) higher than in females. The prevalence of S. mansoni and S. haematobium showed a statistically significant gender difference (P< 0.05). Conclusion the study had provided evidence of the distribution of schistosomiasis in South Sudan for policy direction and recommended annual preventive chemotherapy with praziquantel in all endemic areas.
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Affiliation(s)
- Mutale Nsakashalo Senkwe
- World Health Organization, Country Office, Juba, South Sudan,,Corresponding author Mutale Nsakashalo Senkwe, World Health Organization, Country Office, Juba, South Sudan,
| | | | | | - Julia Sube
- World Health Organization, Country Office, Juba, South Sudan
| | - Alex Bidali
- World Health Organization, Country Office, Juba, South Sudan
| | - Abias Abe
- National Public Health Laboratory, Ministry of Health, Juba, South Sudan
| | - Adiele Onyeze
- Multicountry Assignment Team, World Health Organisation, Nairobi, Kenya
| | | | | | - Fabian Ndenzako
- World Health Organization, Country Office, Juba, South Sudan
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7
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Ondigo BN, Hamilton RE, Magomere EO, Onkanga IO, Mwinzi PN, Odiere MR, Ganley-Leal L. Potential Utility of Systemic Plasma Biomarkers for Evaluation of Pediatric Schistosomiasis in Western Kenya. Front Immunol 2022; 13:887213. [PMID: 35603171 PMCID: PMC9121796 DOI: 10.3389/fimmu.2022.887213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/08/2022] [Indexed: 01/13/2023] Open
Abstract
Introduction Current diagnostic tools for schistosomiasis are limited, and new tests are necessary to enhance disease diagnosis and surveillance. Identification of novel disease-specific biomarkers may facilitate the development of such tests. We evaluated a panel of biomarkers used in sepsis and parasitic diseases for their potential suitability in the diagnosis of schistosomiasis. Objective The study evaluated the levels of systemic plasma biomarkers in relation to Schistosoma mansoni infection and parasite burden. Methods Six biomarkers were measured in the plasma of children from schistosomiasis-endemic regions using ELISA. The concentration of soluble CD23 (sCD23) and lipopolysaccharide (LPS) was tested in 199 and 124 plasma samples, respectively, while interleukin-6 (IL-6), soluble triggering receptor expressed on myeloid (sTREM) cells, eotaxin-1, and fatty acid-binding protein (FABP) concentrations were tested in 30 plasma samples. Results The concentration of IL-6, eotaxin-1, FABP, and LPS was similar between schistosome-infected and uninfected children. The schistosome-infected children had higher median levels of sTREM and sCD23 as compared to uninfected children, 119.0 (29.9-208.9) versus 10.7 (0.0-73.4) (p = 0.046) and 2,549.0 (1,899.0-3,356.0) vs. 2,035.0 (1,448.0-2,939.0) (p = 0.05), respectively. In addition, sTREM was positively correlated with egg density (p = 0.017). Conclusion Our data show that active schistosomiasis per se is associated with elevated levels of sTREM and sCD23. sTREM has potential diagnostic and prognostic values. However, these biomarkers did not distinguish between children with low egg burden and uninfected children.
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Affiliation(s)
- Bartholomew N. Ondigo
- Department of Biochemistry and Molecular Biology, Faculty of Science, Egerton University, Egerton, Kenya,*Correspondence: Bartholomew N. Ondigo,
| | - Rachael E. Hamilton
- School of Public Health, Boston University, Boston, MA, United States,Global Development, Elegance Biotechnologies, Wayne, PA, United States
| | - Edwin O. Magomere
- Department of Biochemistry and Molecular Biology, Faculty of Science, Egerton University, Egerton, Kenya
| | - Isaac O. Onkanga
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Pauline N. Mwinzi
- Regional Office for Africa, World Health Organization, Brazzaville, Democratic Republic of Congo
| | - Maurice R. Odiere
- Centre for Global Health Research, Kenya Medical Research Institute (KEMRI), Kisumu, Kenya
| | - Lisa Ganley-Leal
- Global Development, Elegance Biotechnologies, Wayne, PA, United States
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8
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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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Kovach JD, Long JC, Barbosa LM, Moura ARSS, Silva LK, Reis MG, Blanton RE. A Schistosoma mansoni tri- and tetramer microsatellite catalog for genetic population diversity and differentiation. Int J Parasitol 2021; 51:1007-1014. [PMID: 34022195 DOI: 10.1016/j.ijpara.2021.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/20/2021] [Accepted: 04/28/2021] [Indexed: 02/08/2023]
Abstract
All Schistosoma mansoni tri- and tetranucleotide repeat microsatellites published as of December 2018 were identified. All 52 were evaluated for autosomal location, strength of amplification, scorability and behavior as single-copy loci by polyacrylamide and capillary gel electrophoresis. Of these, 27 were unique, autosomal, polymorphic, easily scored and single copy as assessed on pooled adult worm DNA from two different continental origins and adult worm clones. These microsatellites were distributed across all seven autosomal chromosomes. On laboratory strains their heterozygosity ranged from 0.22 to 0.77. Individual markers had 5-13 alleles, allelic richness of 2-10 and an effective allele number of 1.3-8.14. Those infected by Schistosoma mansoni carry many genetically distinct, sexually reproducing parasites, therefore, for an individual infection the complete allele frequency profile of their progeny consists of a pool of DNA from multiple diploid eggs. Using a set of 25 microsatellites, we calculated allele frequency profiles of eggs in fecal samples from people in two Brazilian communities separated by 6 km: Jenipapo (n = 80) and Volta do Rio (n = 38). There were no a priori characteristics that could predict the performance of markers in natural infections based on their performance with laboratory strains. Increasing marker number did not change accuracy for differentiation and diversity but did improve precision. Our data suggest that using a random set of 10-20 microsatellites appears to result in values that exhibit low standard deviations for diversity and differentiation indices. All identified microsatellites as well as PCR conditions, allele size, primer sequences and references for all tri- and tetramer microsatellites markers presented in this work are available at: https://sites.google.com/case.edu/cwru-and-fiocruz-wdrc/home.
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Affiliation(s)
- Jeffrey D Kovach
- Center for Global Health and Diseases, Case Western Reserve University, Biomedical Research Building, 2109 Adelbert Rd., Cleveland, OH 44106, USA
| | - Jeffrey C Long
- University of New Mexico, Department of Anthropology, Albuquerque, 1 University of New Mexico, NM 87131, USA
| | - Lúcio M Barbosa
- Bahiana School of Medicine and Public Health, Av. Silveira Martins, n° 3386, Salvador, Bahia 41150-100, Brazil; Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil
| | - Ana Rafaela Silva Simões Moura
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil
| | - Luciano K Silva
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil
| | - Mitermayer G Reis
- Gonçalo Moniz Research Centre, Oswaldo Cruz Foundation, Rua Waldemar Falcão, 121 Brotas, Salvador, Bahia 40296-710, Brazil; School of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil; Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Ronald E Blanton
- Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, Tidewater Building, 1440 Canal Street, New Orleans, LA 70112, USA.
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Profiro de Oliveira JH, Arruda IES, Izak Ribeiro de Araújo J, Chaves LL, de La Rocca Soares MF, Soares-Sobrinho JL. Why do few drug delivery systems to combat neglected tropical diseases reach the market? An analysis from the technology's stages. Expert Opin Ther Pat 2021; 32:89-114. [PMID: 34424127 DOI: 10.1080/13543776.2021.1970746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Many drugs used to combat schistosomiasis, Chagas disease, and leishmaniasis (SCL) have clinical limitations such as: high toxicity to the liver, kidneys and spleen; reproductive, gastrointestinal, and heart disorders; teratogenicity. In this sense, drug delivery systems (DDSs) have been described in the literature as a viable option for overcoming the limitations of these drugs. An analysis of the level of development (TRL) of patents can help in determine the steps that must be taken for promising technologies to reach the market. AREAS COVERED This study aimed to analyze the stage of development of DDSs for the treatment of SCL described in patents. In addition, we try to understand the main reasons why many DDSs do not reach the market. In this study, we examined DDSs for drugs indicated by WHO and treatment of SCL, by performing a search for patents. EXPERT OPINION In this present work we provide arguments that support the hypothesis that there is a lack of integration between academia and industry to finance and continue research, especially the development of clinical studies. We cite the translational research consortia as the potential alternative for developing DDSs to combat NTDs.
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Affiliation(s)
| | | | | | - Luise Lopes Chaves
- Department of Pharmacy, Federal University of Pernambuco, Recife, Recife-Pernambuco
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Mutuku MW, Laidemitt MR, Spaan JM, Mwangi IN, Ochanda H, Steinauer ML, Loker ES, Mkoji GM. Comparative Vectorial Competence of Biomphalaria sudanica and Biomphalaria choanomphala, Snail Hosts of Schistosoma mansoni, From Transmission Hotspots In Lake Victoria, Western Kenya. J Parasitol 2021; 107:349-357. [PMID: 33906231 DOI: 10.1645/20-138] [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] [Indexed: 11/10/2022] Open
Abstract
Schistosoma mansoni, which causes human intestinal schistosomiasis, continues to be a major public health concern in the Lake Victoria basin in western Kenya, with Biomphalaria sudanica (a shoreline inhabiting snail) and Biomphalaria choanomphala (a deep-water snail) playing roles in transmission. A recent study showed that B. sudanica was abundantly present near all study villages on the lakeshore, but B. choanomphala was significantly more abundant near villages known to be persistent transmission hotspots. The present study investigated the relative compatibility of B. sudanica and B. choanomphala with S. mansoni. A reciprocal cross-infection experiment used young adult F1 generation B. sudanica and B. choanomphala that were exposed to either 1, 5, or 10 sympatric or allopatric human-derived S. mansoni miracidia. Three weeks post-exposure (PE) and weekly thereafter, the snails were counted and screened for schistosome cercariae, and at 7 wk PE, total cercariae shed during a 2 hr period by each infected snail was determined. Pre-patent periods for S. mansoni in both B. sudanica and B. choanomphala were similar, and most snails in all exposure combinations started shedding cercariae 5 wk PE. Prevalences were significantly higher in B. choanomphala (12.2-80.9%) than in B. sudanica (5.2-18.6%) at each dose, regardless of whether miracidia were of an allopatric or a sympatric source (P < 0.0001). Overall, the odds of a snail becoming infected with 5 or 10 miracidia were significantly higher than the odds of being infected with 1 miracidium, (P < 0.0001), and fewer cercariae were produced by snails exposed to single as compared to 5 or 10 miracidia. On average, B. choanomphala produced more cercariae ( = 458, SD = 414) than B. sudanica ( = 238, SD = 208) (P < 0.0001). These results suggest that B. choanomphala is more compatible with S. mansoni than B. sudanica. Though B. choanomphala can be found in shallow shoreline waters, it is, for the most part, a deeper-water taxon. Because dredging is a relatively inefficient means of sampling, B. choanomphala is likely underestimated with respect to its population size, the number of S. mansoni-positive snails, and its role in maintaining transmission.
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Affiliation(s)
- Martin W Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya.,School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Martina R Laidemitt
- Center for Evolutionary and Theoretical Immunology, Parasitology Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
| | - Johannie M Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Ibrahim N Mwangi
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Horace Ochanda
- School of Biological Sciences, College of Biological and Physical Sciences, University of Nairobi, Nairobi, Kenya
| | - Michelle L Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Eric S Loker
- Center for Evolutionary and Theoretical Immunology, Parasitology Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico 87131
| | - Gerald M Mkoji
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
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Mahende MK, Huber E, Kourany-Lefoll E, Ali A, Hayward B, Bezuidenhout D, Bagchus W, Kabanywanyi AM. Comparative palatability of orally disintegrating tablets (ODTs) of Praziquantel (L-PZQ and Rac-PZQ) versus current PZQ tablet in African children: A randomized, single-blind, crossover study. PLoS Negl Trop Dis 2021; 15:e0007370. [PMID: 34106922 PMCID: PMC8216518 DOI: 10.1371/journal.pntd.0007370] [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: 04/08/2019] [Revised: 06/21/2021] [Accepted: 04/29/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Praziquantel (PZQ) is currently the only recommended drug for infection and disease caused by the schistosome species that infects humans; however, the current tablet formulation is not suitable for pre-school age children mainly due to its bitterness and the large tablet size. We assessed the palatability of two new orally disintegrating tablet (ODT) formulations of PZQ. METHODOLOGY This randomized, single-blind, crossover, swill-and-spit palatability study (NCT02315352) was carried out at a single school in Tanzania in children aged 6-11 years old, with or without schistosomiasis infection as this was not part of the assessment. Children were stratified according to age group (6-8 years or 9-11 years) and gender, then randomized to receive each formulation in a pre-specified sequence. Over 2 days, the children assessed the palatability of Levo-Praziquantel (L-PZQ) ODT 150 mg and Racemate Praziquantel (Rac-PZQ) ODT 150 mg disintegrated in the mouth without water on the first day, and L-PZQ and Rac-PZQ dispersed in water and the currently available PZQ 600 mg formulation (PZQ-Cesol) crushed and dispersed in water on the second day. The palatability of each formulation was rated using a 100 mm visual analogue scale (VAS) incorporating a 5-point hedonic scale, immediately after spitting out the test product (VASt = 0 primary outcome) and after 2-5 minutes (VASt = 2-5). PRINCIPAL FINDINGS In total, 48 children took part in the assessment. Overall, there was no reported difference in the VASt = 0 between the two ODT formulations (p = 0.106) without water. Higher VASt = 0 and VASt = 2-5 scores were reported for L-PZQ ODT compared with Rac-PZQ ODT in older children (p = 0.046 and p = 0.026, respectively). The VASt = 0 and VASt = 2-5 were higher for both ODT formulations compared with the standard formulation (p<0.001 for both time points). No serious adverse events were reported. CONCLUSIONS/SIGNIFICANCE The new paediatric-friendly formulations dispersed in water were both found to be more palatable than the existing standard formulation of PZQ. There may be gender and age effects on the assessment of palatability. Further research is needed for assessing efficacy and tolerability of the newly ODTs Praziquantel drug in younger children. TRIAL REGISTRATION The trial was registered on ClinicalTrials.gov (NCT02315352) and in the Pan African Clinical Trials Registry (PACTR201412000959159).
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Affiliation(s)
| | - Eric Huber
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Elly Kourany-Lefoll
- Ares Trading S.A., Eysins, Switzerland, an affiliate of Merck KGaA, Darmstadt, Germany
| | - Ali Ali
- Ifakara Health Institute, Dar es Salaam, Tanzania
| | - Brooke Hayward
- EMD Serono, Inc. Rockland, Massachusetts, United States, an affiliate of Merck KGaA, Darmstadt, Germany
| | - Deon Bezuidenhout
- Merck (Pty) Ltd, Modderfontein, South Africa an affiliate of Merck KGaA, Darmstadt, Germany
| | - Wilhelmina Bagchus
- Merck Institute of Pharmacometrics, Lausanne, Switzerland, an affiliate of Merck KGaA, Darmstadt, Germany
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Wanderley FSO, Montarroyos U, Bonfim C, Cunha-Correia C. Effectiveness of mass treatment of Schistosoma mansoni infection in socially vulnerable areas of a state in northeastern Brazil, 2011-2014. ACTA ACUST UNITED AC 2021; 79:30. [PMID: 33750474 PMCID: PMC7941929 DOI: 10.1186/s13690-021-00549-9] [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: 09/22/2020] [Accepted: 02/21/2021] [Indexed: 11/21/2022]
Abstract
Background To assess the effectiveness of mass treatment of Schistosoma mansoni infection in socially vulnerable endemic areas in northeastern Brazil. Method An ecological study was conducted, in which 118 localities in 30 municipalities in the state of Pernambuco were screened before 2011 and in 2014 (after mass treatment). Information on the endemic baseline index, mass treatment coverage, socio-environmental conditions and social vulnerability index were used in the multiple correspondence analysis. One hundred fourteen thousand nine hundred eighty-seven people in 118 locations were examined. Results The first two dimensions of the multiple correspondence analysis represented 55.3% of the variability between locations. The human capital component of the social vulnerability index showed an association with the baseline endemicity index. There was a significant reduction in positivity for schistosomes. For two rounds, for every extra 1% of initial endemicity index, the fixed effect of 13.62% increased by 0.0003%, achieving at most 15.94%. Conclusions The mass treatment intervention helped to reduce transmission of schistosomiasis in areas of high endemicity. Thus, it can be recommended that application of mass treatment should be accompanied by other control actions, such as basic sanitation, monitoring of intermediate vectors and case surveillance. Supplementary Information The online version contains supplementary material available at 10.1186/s13690-021-00549-9.
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Affiliation(s)
- Flávia Silvestre Outtes Wanderley
- Department of Neurology, Faculdade de Ciências Médicas, Postgraduate Course on Health Sciences, University of Pernambuco, Rua Arnóbio Marques, 310, Santo Amaro, Recife, Pernambuco, CEP 50100-130, Brazil
| | - Ulisses Montarroyos
- Department of Neurology, Faculdade de Ciências Médicas, Postgraduate Course on Health Sciences, University of Pernambuco, Rua Arnóbio Marques, 310, Santo Amaro, Recife, Pernambuco, CEP 50100-130, Brazil
| | - Cristine Bonfim
- Social Research Department, Joaquim Nabuco Foundation, Recife, PE, Brazil
| | - Carolina Cunha-Correia
- Department of Neurology, Faculdade de Ciências Médicas, Postgraduate Course on Health Sciences, University of Pernambuco, Rua Arnóbio Marques, 310, Santo Amaro, Recife, Pernambuco, CEP 50100-130, Brazil.
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Ouattara M, Diakité NR, Yao PK, Saric J, Coulibaly JT, Assaré RK, Bassa FK, Koné N, Guindo-Coulibaly N, Hattendorf J, Utzinger J, N’Goran EK. Effectiveness of school-based preventive chemotherapy strategies for sustaining the control of schistosomiasis in Côte d'Ivoire: Results of a 5-year cluster randomized trial. PLoS Negl Trop Dis 2021; 15:e0008845. [PMID: 33449924 PMCID: PMC7810315 DOI: 10.1371/journal.pntd.0008845] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 09/30/2020] [Indexed: 11/18/2022] Open
Abstract
Background Preventive chemotherapy using praziquantel is the mainstay for schistosomiasis control. However, there is little evidence on what is supposed to be the most effective school-based treatment strategy to sustain morbidity control. The aim of this study was to compare differences in Schistosoma mansoni prevalence and infection intensity between three different schedules of school-based preventive chemotherapy in an area with moderate prevalence of S. mansoni in Côte d’Ivoire. Methodology Seventy-five schools were randomly assigned to one of three intervention arms: (i) annual school-based preventive chemotherapy with praziquantel (40 mg/kg) over four years; (ii) praziquantel treatment only in the first two years, followed by two years whithout treatment; and (iii) praziquantel treatment in years 1 and 3 without treatment in-between. Cross-sectional parasitologic surveys were carried out prior to each round of preventive chemotherapy. The difference in S. mansoni prevalence and infection intensity was assessed by multiple Kato-Katz thick smears, among children aged 9–12 years at the time of each survey. First-grade children, aged 5–8 years who had never received praziquantel, were also tested at baseline and at the end of the study. Principal findings Overall, 7,410 children aged 9–12 years were examined at baseline and 7,223 at the final survey. The baseline prevalence of S. mansoni was 17.4%, 20.2%, and 25.2% in arms 1, 2, and 3, respectively. In the final year, we observed the lowest prevalence of 10.4% in arm 1, compared to 18.2% in arm 2 and 17.5% in arm 3. The comparison between arms 1 and 2 estimated an odds ratio (OR) of 0.52 but the difference was not statistically significant (95% confidence interval (CI) = 0.23–1.16). Likewise the difference between arms 1 and 3 lacked statistical significance (OR = 0.55, 95% CI = 0.23–1.29). There was no noteworthy difference observed between arms 2 and 3 (OR = 1.06, 95% CI = 0.64–1.75). The lowest S. mansoni fecal egg counts in the final year survey were observed in arm 1 (7.9 eggs per gram of stool (EPG)). However, compared with 11.5 EPG in arm 2 and 15.4 EPG in arm 3, the difference lacked statistical significance. There were 4,812 first-grade children examined at baseline and 4,513 in the final survey. The overall prevalence of S. mansoni in these children slightly decreased in arms 1 (from 4.5% to 3.6%) and 2 (from 4.7% to 4.3%), but increased in arm 3 (from 6.8% to 7.9%). However, there was no significant difference in prevalence and infection intensity observed between study arms. Conclusions/significance The three treatment schedules investigated led to a reduction in the prevalence and intensity of S. mansoni infection among children aged 9–12 years. Comparing intervention arms at the end of the study, no statistically significant differences were observed between annual treatement and the other two treatment schedules, neither in reduction of prevalence nor intensity of infection. It is important to combine our results with those of three sister trials conducted simultaneously in other African countries, before final recommendations can be drawn. The World Health Organization (WHO) recommends preventive chemotherapy with praziquantel as the global strategy for morbidity control of schistosomiasis. The guidelines include target groups and treatment frequencies based on prevalence in school-age children. However, these recommendations are based on expert opinion. The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) put forward a series of cluster-randomized trials in different African countries, including Côte d’Ivoire, to identify the most suitable approach to gain and sustain the control of schistosomiasis. Results from Côte d’Ivoire did not show statistically significant differences between three school-based treatment schedules (i.e., annual treatment over four years; treatment only in the first two years, followed by two years whithout treatment; and treatment every other year without treatment in-between) in reducing prevalence and intensity of Schistosoma mansoni infection among children aged 9–12 years. The results in first-grade children with an age of 5–8 years entering school who had never received deworming drugs showed no significant difference in the prevalence and intensity of S. mansoni infection between the different treatments at the study end, suggesting that the three strategies were not significantly different for reducing the disease transmission in affected communities. However, our data should be combined with other SCORE studies carried out elsewhere in Africa. A meta-analysis including the results of the sister trials could help to conclude and make more generic recommendations.
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Affiliation(s)
- Mamadou Ouattara
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- * E-mail:
| | - Nana R. Diakité
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Patrick K. Yao
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Jasmina Saric
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jean T. Coulibaly
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Rufin K. Assaré
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Fidèle K. Bassa
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Naférima Koné
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Négnorogo Guindo-Coulibaly
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
| | - Jan Hattendorf
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Eliézer K. N’Goran
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d’Ivoire
- Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
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15
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Shen Y, Sung MH, King CH, Binder S, Kittur N, Whalen CC, Colley DG. Modeling Approaches to Predicting Persistent Hotspots in SCORE Studies for Gaining Control of Schistosomiasis Mansoni in Kenya and Tanzania. J Infect Dis 2020; 221:796-803. [PMID: 31621850 PMCID: PMC7026890 DOI: 10.1093/infdis/jiz529] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 10/10/2019] [Indexed: 11/13/2022] Open
Abstract
Background Some villages, labeled “persistent hotspots (PHS),” fail to respond adequately in regard to prevalence and intensity of infection to mass drug administration (MDA) for schistosomiasis. Early identification of PHS, for example, before initiating or after 1 or 2 years of MDA could help guide programmatic decision making. Methods In a study with multiple rounds of MDA, data collected before the third MDA were used to predict PHS. We assessed 6 predictive approaches using data from before MDA and after 2 rounds of annual MDA from Kenya and Tanzania. Results Generalized linear models with variable selection possessed relatively stable performance compared with tree-based methods. Models applied to Kenya data alone or combined data from Kenya and Tanzania could reach over 80% predictive accuracy, whereas predicting PHS for Tanzania was challenging. Models developed from one country and validated in another failed to achieve satisfactory performance. Several Year-3 variables were identified as key predictors. Conclusions Statistical models applied to Year-3 data could help predict PHS and guide program decisions, with infection intensity, prevalence of heavy infections (≥400 eggs/gram of feces), and total prevalence being particularly important factors. Additional studies including more variables and locations could help in developing generalizable models.
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Affiliation(s)
- Ye Shen
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, USA
| | - Meng-Hsuan Sung
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, USA
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Christopher C Whalen
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, Georgia, USA.,Global Health Institute, University of Georgia, Athens, Georgia, USA
| | - Daniel G Colley
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA.,Department of Microbiology, University of Georgia, Athens, Georgia, USA
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Phillips AE, Tohon Z, Dhanani NA, Sofo B, Gnandou I, Sidikou B, Noma AG, Madougou B, Alto O, Sebangou H, Halilou KM, Andia R, Garba A, Fenwick A, Hamidou AA. Evaluating the impact of biannual school-based and community-wide treatment on urogenital schistosomiasis in Niger. Parasit Vectors 2020; 13:557. [PMID: 33203477 PMCID: PMC7672903 DOI: 10.1186/s13071-020-04411-9] [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: 06/29/2020] [Accepted: 10/21/2020] [Indexed: 11/10/2022] Open
Abstract
Background The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) coordinated a five-year study implemented in several countries, including Niger, to provide an evidence-base for programmatic decisions regarding cost-effective approaches to preventive chemotherapy for schistosomiasis control. Methods This was a cluster-randomised trial investigating six possible combinations of annual or biannual community-wide treatment (CWT), school-based treatment (SBT), and holidays from mass treatment over four years. The most intense arm involved two years of annual CWT followed by 2 years of biannual CWT, while the least intensive arm involved one year of annual SBT followed by a year without treatment and two more years of annual SBT. The primary outcome of interest was prevalence and intensity of Schistosoma haematobium among 100 children aged 9–12 years sampled each year. In addition, 100 children aged 5–8 years in their first year of school and 50 adults (aged 20–55 years) were tested in the first and final fifth year of the study. Results In total, data were collected from 167,500 individuals across 225 villages in nine districts within the Niger River valley, Western Niger. Overall, the prevalence of S. haematobium decreased from baseline to Year 5 across all study arms. The relative reduction of prevalence was greater in biannual compared with annual treatment across all arms; however, the only significant difference was seen in areas with a high starting prevalence. Although adults were not targeted for treatment in SBT arms, a statistically significant decrease in prevalence among adults was seen in moderate prevalence areas receiving biannual (10.7% to 4.8%) SBT (P < 0.001). Adults tested in the annual SBT group also showed a decrease in prevalence between Year 1 and Year 5 (12.2% to 11.0%), but this difference was not significant. Conclusions These findings are an important consideration for schistosomiasis control programmes that are considering elimination and support the idea that scaling up the frequency of treatment rounds, particularly in areas of low prevalence, will not eliminate schistosomiasis. Interestingly, the finding that prevalence decreased among adults in SBT arms suggests that transmission in the community can be reduced, even where only school children are being treated, which could have logistical and cost-saving implications for the national control programmes.
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Affiliation(s)
- Anna E Phillips
- London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Imperial College London, London, UK.
| | - Zilahatou Tohon
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Neerav A Dhanani
- Schistosomiasis control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Boubacar Sofo
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | | | - Boubacar Sidikou
- Hôpital National de Niamey rond-point Hôpital, BP 238, Niamey, Niger
| | - Adamou Garba Noma
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Bassirou Madougou
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Oumarou Alto
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Hannatou Sebangou
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Kader M Halilou
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Roumanatou Andia
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Amadou Garba
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
| | - Alan Fenwick
- Schistosomiasis control Initiative (SCI), Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Amina A Hamidou
- Aménagement et Lutte (RISEAL NIGER), Réseau International Schistosomiases Environnement, Avenue de l'indépendance, BP. 13724, Niamey, Niger
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Binder S, Campbell CH, Castleman JD, Kittur N, Kinung'hi SM, Olsen A, Magnussen P, Karanja DMS, Mwinzi PNM, Montgomery SP, Secor WE, Phillips AE, Dhanani N, Gazzinelli-Guimaraes PH, Clements MN, N'Goran EK, Meite A, Utzinger J, Hamidou AA, Garba A, Fleming FM, Whalen CC, King CH, Colley DG. Lessons Learned in Conducting Mass Drug Administration for Schistosomiasis Control and Measuring Coverage in an Operational Research Setting. Am J Trop Med Hyg 2020; 103:105-113. [PMID: 32400352 PMCID: PMC7351302 DOI: 10.4269/ajtmh.19-0789] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was created to conduct research that could inform programmatic decision-making related to schistosomiasis. SCORE included several large cluster randomized field studies involving mass drug administration (MDA) with praziquantel. The largest of these were studies of gaining or sustaining control of schistosomiasis, which were conducted in five African countries. To enhance relevance for routine practice, the MDA in these studies was coordinated by or closely aligned with national neglected tropical disease (NTD) control programs. The study protocol set minimum targets of at least 90% for coverage among children enrolled in schools and 75% for all school-age children. Over the 4 years of intervention, an estimated 3.5 million treatments were administered to study communities. By year 4, the median village coverage was at or above targets in all studies except that in Mozambique. However, there was often a wide variation behind these summary statistics, and all studies had several villages with very low or high coverage. In studies where coverage was estimated by comparing the number of people treated with the number eligible for treatment, denominator estimation was often problematic. The SCORE experiences in conducting these studies provide lessons for future efforts that attempt to implement strong research designs in real-world contexts. They also have potential applicability to country MDA campaigns against schistosomiasis and other NTDs, most of which are conducted with less logistical and financial support than was available for the SCORE study efforts.
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Affiliation(s)
- Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Jennifer D Castleman
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Safari M Kinung'hi
- Mwanza Research Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Annette Olsen
- Section for Parasitology and Aquatic Pathobiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pascal Magnussen
- Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Diana M S Karanja
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Pauline N M Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Susan P Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - William Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Anna E Phillips
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Neerav Dhanani
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | | | - Michelle N Clements
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Eliézer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Aboulaye Meite
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, Abidjan, Côte d'Ivoire
| | - Jürg Utzinger
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Amina A Hamidou
- Réseau International Schistosomoses, Environnement, Aménagement et Lutte (RISEAL-Niger), Niamey, Niger
| | - Amadou Garba
- Department of Control of Neglected Tropical Diseases, Preventive Chemotherapy and Transmission Control Unit, World Health Organization, Geneva, Switzerland
| | - Fiona M Fleming
- Schistosomiasis Control Initiative, Imperial College, London, United Kingdom
| | - Christopher C Whalen
- Department of Epidemiology and Biostatistics, Global Health Institute, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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18
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Shen Y, Wiegand RE, Olsen A, King CH, Kittur N, Binder S, Zhang F, Whalen CC, Secor WE, Montgomery SP, Mwinzi PNM, Magnussen P, Kinung'hi S, Campbell CH, Colley DG. Five-Year Impact of Different Multi-Year Mass Drug Administration Strategies on Childhood Schistosoma mansoni-Associated Morbidity: A Combined Analysis from the Schistosomiasis Consortium for Operational Research and Evaluation Cohort Studies in the Lake Victoria Regions of Kenya and Tanzania. Am J Trop Med Hyg 2020; 101:1336-1344. [PMID: 31407653 PMCID: PMC6896894 DOI: 10.4269/ajtmh.19-0273] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The WHO recommends mass treatment with praziquantel as the primary approach for Schistosoma mansoni-related morbidity control in endemic populations. The Schistosomiasis Consortium for Operational Research and Evaluation implemented multi-country, cluster-randomized trials to compare effectiveness of community-wide and school-based treatment (SBT) regimens on prevalence and intensity of schistosomiasis. To assess the impact of two different treatment schedules on S. mansoni-associated morbidity in children, cohort studies were nested within the randomized trials conducted in villages in Kenya and Tanzania having baseline prevalence ≥ 25%. Children aged 7-8 years were enrolled at baseline and followed to ages 11-12 years. Infection intensity and odds of infection were reduced both in villages receiving four years of annual community-wide treatment (CWT) and those who received biennial SBT over 4 years. These regimens were also associated with reduced odds of undernutrition and reduced odds of portal vein dilation at follow-up. However, neither hemoglobin levels nor the prevalence of the rare abnormal pattern C liver scores on ultrasound improved. For the combined cohorts, growth stunting worsened in the areas receiving biennial SBT, and maximal oxygen uptake as estimated by fitness testing scores declined under both regimens. After adjusting for imbalance in starting prevalence between study arms, children in villages receiving annual CWT had significantly greater decreases in infection prevalence and intensity than those villages receiving biennial SBT. Although health-related quality-of-life scores improved in both study arms, children in the CWT villages gained significantly more. We conclude that programs using annual CWT are likely to achieve better overall S. mansoni morbidity control than those implementing only biennial SBT.
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Affiliation(s)
- Ye Shen
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia
| | - Ryan E Wiegand
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Annette Olsen
- Section for Parasitology and Aquatic Pathobiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charles H King
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia.,Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Feng Zhang
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia
| | - Christopher C Whalen
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia
| | - William Evan Secor
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Susan P Montgomery
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Pauline N M Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Pascal Magnussen
- Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Safari Kinung'hi
- Mwanza Research Centre, National Institute for Medical Research, Mwanza, Tanzania
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation, Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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19
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Kittur N, King CH, Campbell CH, Kinung'hi S, Mwinzi PNM, Karanja DMS, N'Goran EK, Phillips AE, Gazzinelli-Guimaraes PH, Olsen A, Magnussen P, Secor WE, Montgomery SP, Utzinger J, Walker JW, Binder S, Colley DG. Persistent Hotspots in Schistosomiasis Consortium for Operational Research and Evaluation Studies for Gaining and Sustaining Control of Schistosomiasis after Four Years of Mass Drug Administration of Praziquantel. Am J Trop Med Hyg 2020; 101:617-627. [PMID: 31287046 PMCID: PMC6726953 DOI: 10.4269/ajtmh.19-0193] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Control of schistosomiasis presently relies largely on preventive chemotherapy with praziquantel through mass drug administration (MDA) programs. The Schistosomiasis Consortium for Operational Research and Evaluation has concluded five studies in four countries (Côte d’Ivoire, Kenya, Mozambique, and Tanzania) to evaluate alternative approaches to MDA. Studies involved four intervention years, with final evaluation in the fifth year. Mass drug administration given annually or twice over 4 years reduced average prevalence and intensity of schistosome infections, but not all villages that were treated in the same way responded similarly. There are multiple ways by which responsiveness to MDA, or the lack thereof, could be measured. In the analyses presented here, we defined persistent hotspots (PHS) as villages that achieved less than 35% reduction in prevalence and/or less than 50% reduction in infection intensity after 4 years of either school-based or community-wide MDA, either annually or twice in 4 years. By this definition, at least 30% of villages in each of the five studies were PHSs. We found no consistent relationship between PHSs and the type or frequency of intervention, adequacy of reported MDA coverage, and prevalence or intensity of infection at baseline. New research is warranted to identify PHSs after just one or a few rounds of MDA, and new adaptive strategies need to be advanced and validated for turning PHSs into responder villages.
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Affiliation(s)
- Nupur Kittur
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Charles H King
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Carl H Campbell
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Safari Kinung'hi
- National Institute for Medical Research, Mwanza Research Centre, Mwanza, Tanzania
| | - Pauline N M Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Diana M S Karanja
- Neglected Tropical Diseases Branch, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eliezer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Anna E Phillips
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, Imperial College London, London, United Kingdom
| | - Pedro H Gazzinelli-Guimaraes
- Department of Infectious Disease Epidemiology, Schistosomiasis Control Initiative, Imperial College London, London, United Kingdom
| | - Annette Olsen
- Section for Parasitology and Aquatic Pathobiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pascal Magnussen
- Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - W Evan Secor
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Susan P Montgomery
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Juerg Utzinger
- University of Basel, Basel, Switzerland.,Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Joseph W Walker
- Odum School of Ecology, University of Georgia, Athens, Georgia.,Department of Epidemiology, College of Public Health, University of Georgia, Athens, Georgia
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Schistosomiasis Consortium for Operational Research and Evaluation (SCORE), Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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20
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Differential impact of mass and targeted praziquantel delivery on schistosomiasis control in school-aged children: A systematic review and meta-analysis. PLoS Negl Trop Dis 2019; 13:e0007808. [PMID: 31603895 PMCID: PMC6808504 DOI: 10.1371/journal.pntd.0007808] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 10/23/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023] Open
Abstract
Background Schistosomiasis is a widespread public health concern in the poorest regions of the world. The principal control strategy is regular praziquantel administration to school-aged children in endemic areas. With calls for the elimination of schistosomiasis as a public health problem, expanding praziquantel delivery to all community members has been advocated. This systematic review and meta-analysis compares the impact of community-wide and child-targeted praziquantel distribution on schistosomiasis prevalence and intensity in school-aged children. Methodology/Principal findings We searched MEDLINE, Embase and Web of Science to identify papers that reported schistosome prevalence before and after praziquantel administration, either to children only or to all community members. Extracted data included Schistosoma species, drug administration strategy, number of treatment rounds, follow-up interval and prevalence and intensity before and after treatment. We used inverse variance weighted generalised linear models to examine the impact of mass versus targeted drug administration on prevalence reduction, and weighted boxplots to examine the impact on infection intensity reduction. This study is registered with PROSPERO, number CRD42018095377. In total, 34 articles were eligible for systematic review and 28 for meta-analysis. Schistosoma mansoni was reported in 20 studies; Schistosoma haematobium in 19 studies, and Schistosoma japonicum in two studies. Results of generalised linear models showed no detectable difference between mass and targeted treatment strategies on prevalence reduction in school-aged children for S. mansoni (odds ratio 0.47, 95%CI 0.13–1.68, p = 0.227) and S. haematobium (0.41, 95%CI 0.06–3.03, p = 0.358). Box plots also showed no apparent differences in intensity reduction between the two treatment strategies. Conclusions/Significance The results of this meta-analysis do not support the hypothesis that community-wide treatment is more effective than targeted treatment at reducing schistosomiasis infections in children. This may be due to the relatively small number of included studies, insufficient treatment coverage, persistent infection hotspots and unmeasured confounders. Further field-based studies comparing mass and targeted treatment are required. Schistosomiasis is a neglected tropical disease, caused by parasitic worms, that affects more than 143 million people worldwide. Chronic infections can lead to significant morbidity including kidney damage, anaemia, malnutrition, infertility and growth impairment. School-aged children between six and 15 years are often targeted for regular treatment with praziquantel in large-scale drug delivery programs, because they suffer a disproportionate burden of morbidity. On the other hand, a mass drug delivery strategy that treats all members of the community has been suggested in a move towards elimination of schistosomiasis as a public health problem. In this systematic review, we assess the impact of community-wide versus children-only praziquantel distribution in reducing schistosomiasis infections in school-aged children. We did not detect a difference between mass and targeted treatment strategies, possibly due to factors including insufficient treatment coverage and persistent sources of reinfection. Addressing these factors may assist in optimising control programs.
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21
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Mutsaka-Makuvaza MJ, Matsena-Zingoni Z, Tshuma C, Ray S, Zhou XN, Webster B, Midzi N. Reinfection of urogenital schistosomiasis in pre-school children in a highly endemic district in Northern Zimbabwe: a 12 months compliance study. Infect Dis Poverty 2018; 7:102. [PMID: 30268157 PMCID: PMC6162945 DOI: 10.1186/s40249-018-0483-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/04/2018] [Indexed: 12/19/2022] Open
Abstract
Background In light of the shift to aiming for schistosomiasis elimination, the following are needed: data on reinfection patterns, participation, and sample submission adherence of all high-risk age groups to intervention strategies. This study was conducted to assess prevalence, reinfections along with consecutive participation, sample submission adherence, and effect of treatment on schistosomiasis prevalence in children aged five years and below in an endemic district in Zimbabwe, over one year. Methods The study was conducted from February 2016–February 2017 in Madziwa area, Shamva district. Following community mobilisation, mothers brought their children aged 5 years and below for recruitment at baseline and also urine sample collection at baseline, 3, 6, 9 and 12 months follow up surveys. At each time point, urine was tested for urogenital schistosomiasis by urine filtration and children found positive received treatment. Schistosoma haematobium prevalence, reinfections as well as children participation, and urine sample submission at each visit were assessed at each time point for one year. Results Of the 535 children recruited from the five communities, 169 (31.6%) participated consecutively at all survey points. The highest mean number of samples submitted was 2.9 among communities and survey points. S. haematobium prevalence significantly reduced from 13.3% at baseline to 2.8% at 12 months for all participants and from 24.9% at baseline to 1.8% at 12 months (P < 0.001) for participants coming at all- time points. Among the communities, the highest baseline prevalence was found in Chihuri for both the participants coming consecutively (38.5%, 10/26) and all participants (20.4%, 21/103). Reinfections were significantly high at 9 months follow up survey (P = 0.021) and in Mupfure (P = 0.003). New infections significantly decreased over time (P < 0.001). Logistic regression analysis showed that the risk of acquiring schistosomiasis was high in some communities (P < 0.05). Conclusions S. haematobium infections and reinfections are seasonal and depend on micro-geographical settings. The risk of being infected with schistosomes in pre-school aged children increases with increasing age. Sustained treatment of infected individuals in a community reduces prevalence overtime. Participation compliance at consecutive visits and sample submission adherence are important for effective operational control interventions. Electronic supplementary material The online version of this article (10.1186/s40249-018-0483-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Masceline Jenipher Mutsaka-Makuvaza
- Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P. O. Box A178, Avondale, Harare, Zimbabwe.,National Institute of Health Research, Ministry of Health and Child Care, P.O. Box CY573, Causeway, Harare, Zimbabwe
| | - Zvifadzo Matsena-Zingoni
- National Institute of Health Research, Ministry of Health and Child Care, P.O. Box CY573, Causeway, Harare, Zimbabwe.,Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of Witwatersrand, 27 St Andrews' Road, Parktown, Johannesburg, 2193, South Africa
| | - Cremance Tshuma
- Mashonaland Central Provincial Health Office, Ministry of health and Child Care, Bindura, Zimbabwe
| | - Sunanda Ray
- Department of Community Medicine, College of Health Sciences, University of Zimbabwe, P. O. Box A178, Avondale, Harare, Zimbabwe
| | - Xiao-Nong Zhou
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention, Shanghai, People's Republic of China
| | - Bonnie Webster
- Parasites and Vectors Division, National History Museum, London, UK
| | - Nicholas Midzi
- Department of Medical Microbiology, College of Health Sciences, University of Zimbabwe, P. O. Box A178, Avondale, Harare, Zimbabwe.
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22
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Sircar AD, Mwinzi PNM, Onkanga IO, Wiegand RE, Montgomery SP, Secor WE. Schistosoma mansoni Mass Drug Administration Regimens and Their Effect on Morbidity among Schoolchildren over a 5-Year Period-Kenya, 2010-2015. Am J Trop Med Hyg 2018; 99:362-369. [PMID: 29893197 PMCID: PMC6090338 DOI: 10.4269/ajtmh.18-0067] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/22/2018] [Indexed: 12/24/2022] Open
Abstract
Schistosomiasis control programs are designed to reduce morbidity by providing mass drug administration (MDA) of praziquantel to at-risk populations. We compared morbidity markers between two cohorts of Kenyan schoolchildren that initially had high prevalence of Schistosoma mansoni infections. One cohort (N = 416 at year 1) received four rounds of annual MDA in a community-wide treatment (CWT) strategy. The other cohort (N = 386 at year 1) received school-based treatment (SBT) every other year over the 4-year period. We measured infection with S. mansoni and soil-transmitted helminths (STH) as well as subtle morbidity markers at year 1, year 3, and year 5 and compared cohorts with mixed models after controlling for age and gender. At year 5, neither overall S. mansoni prevalence nor the prevalence of high infection-intensity S. mansoni infection was significantly reduced compared with baseline in either the CWT cohort (N = 277 remaining) or the SBT cohort (N = 235 remaining). Nevertheless, by year 5, children in both cohorts demonstrated significant decreases in wasting, ultrasound-detected organomegaly, and STH infection along with significantly improved pediatric quality-of-life scores compared with year 1. Stunting did not change over time, but children who were S. mansoni egg-positive at year 5 had significantly more stunting than children without schistosomiasis. The only significant difference between arms at year 5 was a lower prevalence of STH infections in the CWT group.
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Affiliation(s)
- Anita D. Sircar
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Pauline N. M. Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Isaac O. Onkanga
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ryan E. Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Susan P. Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - W. Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
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23
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Atalabi TE, Adoh SD, Eze KM. The current epidemiological status of urogenital schistosomiasis among primary school pupils in Katsina State, Nigeria: An imperative for a scale up of water and sanitation initiative and mass administration of medicines with Praziquantel. PLoS Negl Trop Dis 2018; 12:e0006636. [PMID: 29979684 PMCID: PMC6051670 DOI: 10.1371/journal.pntd.0006636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 07/18/2018] [Accepted: 06/25/2018] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Human schistosomiasis, a debilitating and chronic disease, is among a set of 17 neglected tropical infectious diseases of poverty that is currently posing a threat to the wellbeing of 2 billion people in the world. The SHAWN/WASH and MAM programmes in the study area require epidemiological data to enhance their effectiveness. We therefore embarked on this cross-sectional study with the aim of investigating the prevalence, intensity and risk factors of urogenital schistosomiasis. METHODOLOGY/ PRINCIPAL FINDINGS Interviewed 484 respondents produced terminal urine samples (between 10.00h - 14.00h) which were analyzed with Medi ─Test Combi 10 and centrifuged at 400 r.p.m for 4 minutes using C2 series Centurion Scientific Centrifuge. Eggs of S. haematobium were identified with their terminal spines using Motic Binocular Microscope. Data were analyzed with Epi Info 7. In this study, the overall prevalence and arithmetic mean intensity of the infection were 8.68% (6.39─ 11.64) and 80.09 (30.92─129.28) eggs per 10ml of urine respectively. Urogenital schistosomiasis was significantly associated with knowledge about the snail host (χ2 = 4.23; P = 0.0398); water contact activities (χ2 = 25.788; P = 0.0001), gender (χ2 = 16.722; P = 0.0001); age (χ2 = 9.589; P = 0.0019); economic status of school attended (χ2 = 4.869; P = 0.0273); residence distance from open water sources (χ2 = 10.546; P = 0.0012); mothers' occupational (χ2 = 6.081; P = 0.0137) and educational status (χ2 = 4.139; P = 0.0419). CONCLUSION/ SIGNIFICANCE The overall prevalence obtained in this survey shows that the study area was at a low-risk degree of endemicity for urogenital schistosomiasis. Beneath this is a subtle, latent and deadly morbidity-inducing heavy mean intensity of infection, calling for urgent implementation of WHO recommendation that MAM with PZQ be carried out twice for School-Age Children (enrolled or not enrolled) during their primary schooling age (once each at the point of admission and graduation). The criteria for classifying endemic areas for schistosomiasis should also be reviewed to capture the magnitude of mean intensity of infection rather than prevalence only as this may underplay its epidemiological severity.
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Affiliation(s)
- Tolulope Ebenezer Atalabi
- Department of Biological Sciences, Faculty of Science, Federal University Dutsin-Ma, Dutsin-Ma, Katsina State, Nigeria
| | - Stephen Dumebi Adoh
- Department of Biological Sciences, Faculty of Science, Federal University Dutsin-Ma, Dutsin-Ma, Katsina State, Nigeria
| | - Kingsley Marvin Eze
- Department of Biological Sciences, Faculty of Science, Federal University Dutsin-Ma, Dutsin-Ma, Katsina State, Nigeria
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24
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Standley CJ, Graeden E, Kerr J, Sorrell EM, Katz R. Decision support for evidence-based integration of disease control: A proof of concept for malaria and schistosomiasis. PLoS Negl Trop Dis 2018; 12:e0006328. [PMID: 29649260 PMCID: PMC5896906 DOI: 10.1371/journal.pntd.0006328] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 02/19/2018] [Indexed: 11/19/2022] Open
Abstract
AUTHOR SUMMARY Designing and implementing effective programs for infectious disease control requires complex decision-making, informed by an understanding of the diseases, the types of disease interventions and control measures available, and the disease-relevant characteristics of the local community. Though disease modeling frameworks have been developed to address these questions and support decision-making, the complexity of current models presents a significant barrier to on-the-ground end users. The picture is further complicated when considering approaches for integration of different disease control programs, where co-infection dynamics, treatment interactions, and other variables must also be taken into account. Here, we describe the development of an application available on the internet with a simple user interface, to support on-the-ground decision-making for integrating disease control, given local conditions and practical constraints. The model upon which the tool is built provides predictive analysis for the effectiveness of integration of schistosomiasis and malaria control, two diseases with extensive geographical and epidemiological overlap. This proof-of-concept method and tool demonstrate significant progress in effectively translating the best available scientific models to support pragmatic decision-making on the ground, with the potential to significantly increase the impact and cost-effectiveness of disease control.
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Affiliation(s)
- Claire J. Standley
- Center for Global Health Science and Security, Georgetown University, Washington, DC, United States of America
- * E-mail:
| | - Ellie Graeden
- Talus Analytics, LLC, Lyons, CO, United States of America
| | - Justin Kerr
- Talus Analytics, LLC, Lyons, CO, United States of America
| | - Erin M. Sorrell
- Center for Global Health Science and Security, Georgetown University, Washington, DC, United States of America
| | - Rebecca Katz
- Center for Global Health Science and Security, Georgetown University, Washington, DC, United States of America
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25
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Abudho BO, Ndombi EM, Guya B, Carter JM, Riner DK, Kittur N, Karanja DMS, Secor WE, Colley DG. Impact of Four Years of Annual Mass Drug Administration on Prevalence and Intensity of Schistosomiasis among Primary and High School Children in Western Kenya: A Repeated Cross-Sectional Study. Am J Trop Med Hyg 2018. [PMID: 29532768 PMCID: PMC5953387 DOI: 10.4269/ajtmh.17-0908] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Schistosomiasis remains a major public health problem in Kenya. The World Health Organization recommends preventive chemotherapy with praziquantel (PZQ) to control morbidity due to schistosomiasis. Morbidity is considered linked to intensity of infection, which along with prevalence is used to determine the frequency of mass drug administration (MDA) to school-age children. We determined the impact of annual school-based MDA on children across all primary and high school years using a repeated cross-sectional study design in five schools near Lake Victoria in western Kenya, an area endemic for Schistosoma mansoni. At baseline and for the following four consecutive years, between 897 and 1,440 school children in Grades 1-12 were enrolled and evaluated by Kato-Katz for S. mansoni and soil-transmitted helminths (STH), followed by annual MDA with PZQ and albendazole. Four annual rounds of MDA with PZQ were associated with reduced S. mansoni prevalence in all school children (44.7-14.0%; P < 0.001) and mean intensity of infection by 91% (90.4 to 8.1 eggs per gram [epg] of stool; P < 0.001). Prevalence of high-intensity infection (≥ 400 epg) decreased from 6.8% at baseline to 0.3% by the end of the study. Soil-transmitted helminth infections, already low at baseline, also decreased significantly over the years. In this high prevalence area, annual school-based MDA with high coverage across all Grades (1-12) resulted in rapid and progressive declines in overall prevalence and intensity of infection. This decrease was dramatic in regard to heavy infections in older school-attending children.
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Affiliation(s)
- Bernard O Abudho
- Department of Biomedical Sciences, School of Public Health, Maseno University, Maseno, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Eric M Ndombi
- Department of Pathology, Kenyatta University, Nairobi, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Bernard Guya
- Department of Biomedical Sciences, School of Public Health, Maseno University, Maseno, Kenya
| | - Jennifer M Carter
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Diana K Riner
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Nupur Kittur
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
| | - Diana M S Karanja
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Daniel G Colley
- Department of Microbiology, University of Georgia, Athens, Georgia.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia
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26
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Wiegand RE, Mwinzi PNM, Montgomery SP, Chan YL, Andiego K, Omedo M, Muchiri G, Ogutu MO, Rawago F, Odiere MR, Karanja DMS, Secor WE. A Persistent Hotspot of Schistosoma mansoni Infection in a Five-Year Randomized Trial of Praziquantel Preventative Chemotherapy Strategies. J Infect Dis 2017; 216:1425-1433. [PMID: 28968877 PMCID: PMC5913648 DOI: 10.1093/infdis/jix496] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/13/2017] [Indexed: 12/28/2022] Open
Abstract
Background Persistent hotspots have been described after mass drug administration (MDA) for the control of schistosomiasis, but they have not been studied during the course of a multiyear MDA program. Methods In data from a 5-year study of school-based and village-wide preventive chemotherapy strategies for Schistosoma mansoni, spatial scan statistics were used to find infection hotspots in 3 populations: 5- to 8-year-olds, 9- to 12-year-olds, and adults. Negative binomial regression was used to analyze changes from baseline, and receiver operating characteristic analyses were used to predict which villages would reach prevalence and intensity endpoints. Results We identified a persistent hotspot, not associated with study arm, where S. mansoni infection prevalence and intensity did not decrease as much as in villages outside the hotspot. Significant differences from baseline were realized after 1 year of MDA: we did not identify factors that moderated this relationship. Villages meeting specified endpoints at year 5 were predicted from prior year data with moderately high sensitivity and specificity. Conclusions The MDA strategies were less effective at reducing prevalence and intensity in the hotspot compared with other villages. Villages that reached year 5 endpoints could be detected earlier, which may provide the opportunity to amend intervention strategies.
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Affiliation(s)
- Ryan E Wiegand
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Pauline N M Mwinzi
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Susan P Montgomery
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Kennedy Andiego
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Martin Omedo
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Geoffrey Muchiri
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Michael O Ogutu
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Fredrick Rawago
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Maurice R Odiere
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - Diana M S Karanja
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu
| | - W Evan Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
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27
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Musuva R, Shen Y, Wei X, Binder S, Ivy JA, Secor WE, Montgomery SP, King CH, Mwinzi PNM. Change in children's school behavior after mass administration of praziquantel for Schistosoma mansoni infection in endemic areas of western Kenya: A pilot study using the Behavioral Assessment System for Children (BASC-2). PLoS One 2017; 12:e0181975. [PMID: 28746403 PMCID: PMC5528892 DOI: 10.1371/journal.pone.0181975] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/10/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Schistosomiasis is a parasite-related chronic inflammatory condition that can cause anemia, decreased growth, liver abnormalities, and deficits in cognitive functioning among children. METHODOLOGY/PRINCIPAL FINDINGS This study used the Behavior Assessment System for Children (BASC-2) to collect data on thirty-six 9-12 year old school-attending children's behavioral profiles in an Schistosoma mansoni-endemic area of western Kenya, before and after treatment with praziquantel for S. mansoni infection. BASC-2 T scores were significantly reduced post-treatment (p < 0.05) for each of the 'negative' behavior categories including externalizing problems (hyperactivity, aggression, and conduct problems that are disruptive in nature), internalizing problems (anxiety, depression, somatization, atypicality, and withdrawal), school problems (academic difficulties, included attention problems and learning problems), and the composite behavioral symptoms index (BSI), signifying improved behavior. While the observed improvement in the 'positive' behavior category of adaptive skills (adaptability, functional communication, social skills, leadership, and study skills) was not statistically significant, there were significant improvements in two adaptive skills subcategories: social skills and study skills. CONCLUSION/SIGNIFICANCE Results of this study suggest that children have better school-related behaviors without heavy S. mansoni infection, and that infected children's behaviors, especially disruptive problem behaviors, improve significantly after praziquantel treatment.
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Affiliation(s)
- Rosemary Musuva
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Ye Shen
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Xianjue Wei
- Department of Epidemiology & Biostatistics, University of Georgia, Athens, Georgia, United States of America
| | - Sue Binder
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
| | - Julianne A. Ivy
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - W. Evan Secor
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Susan P. Montgomery
- Parasitic Diseases Branch, Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Charles H. King
- Schistosomiasis Consortium for Operational Research and Evaluation, University of Georgia, Athens, Georgia, United States of America
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Pauline N. M. Mwinzi
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
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28
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Turner HC, Truscott JE, Bettis AA, Farrell SH, Deol AK, Whitton JM, Fleming FM, Anderson RM. Evaluating the variation in the projected benefit of community-wide mass treatment for schistosomiasis: Implications for future economic evaluations. Parasit Vectors 2017; 10:213. [PMID: 28454578 PMCID: PMC5410074 DOI: 10.1186/s13071-017-2141-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/18/2017] [Indexed: 12/14/2022] Open
Abstract
Background The majority of schistosomiasis control programmes focus on targeting school-aged children. Expanding the use of community-wide mass treatment to reach more adults is under consideration. However, it should be noted that this would require a further increase in programmatic resources, international aid, and commitment for the provision of praziquantel. Consequently, it is important to understand (i) where a change of strategy would have the greatest benefit, and (ii) how generalisable the conclusions of field trials and analytical studies based on mathematical models investigating the impact of community-wide mass treatment, are to a broad range of settings. Methods In this paper, we employ a previously described deterministic fully age-structured schistosomiasis transmission model and evaluate the benefit of community-wide mass treatment both in terms of controlling morbidity and eliminating transmission for Schistosoma mansoni, across a wide range of epidemiological settings and programmatic scenarios. This included variation in the baseline relative worm pre-control burden in adults, the overall level of transmission in defined settings, choice of effectiveness metric (basing morbidity calculations on prevalence or intensity), the level of school enrolment and treatment compliance. Results Community-wide mass treatment was found to be more effective for controlling the transmission of schistosome parasites than using a school-based programme only targeting school-aged children. However, in the context of morbidity control, the potential benefit of switching to community-wide mass treatment was highly variable across the different scenarios analysed. In contrast, for areas where the goal is to eliminate transmission, the projected benefit of community-wide mass treatment was more consistent. Conclusion Whether community-wide mass treatment is appropriate will depend on the local epidemiological setting (i.e. the relative pre-control burden in adults and transmission intensity), and whether the goal is morbidity control or eliminating transmission. This has important implications regarding the generalisability of cost-effectiveness analyses of schistosomiasis interventions. Our results indicate that areas with poor school-enrolment/coverage could benefit more from community-wide treatment of praziquantel and should potentially be prioritised for any change in strategy. This work highlights the importance of not over-generalising conclusions and policy in this area, but of basing decisions on high quality epidemiological data and quantitative analyses of the impact of interventions in a range of settings. Electronic supplementary material The online version of this article (doi:10.1186/s13071-017-2141-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hugo C Turner
- London Centre for Neglected Tropical Disease Research, London, UK. .,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK. .,Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - James E Truscott
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Alison A Bettis
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Sam H Farrell
- London Centre for Neglected Tropical Disease Research, London, UK.,Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, St Marys Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Arminder K Deol
- London Centre for Neglected Tropical Disease Research, London, UK.,Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Jane M Whitton
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Fiona M Fleming
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St. Mary's Campus), Imperial College London, Norfolk Place, London, W2 1PG, 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 Marys Campus, Imperial College London, Norfolk Place, London, W2 1PG, UK
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