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Malizia V, de Vlas SJ, Roes KCB, Giardina F. Revisiting the impact of Schistosoma mansoni regulating mechanisms on transmission dynamics using SchiSTOP, a novel modelling framework. PLoS Negl Trop Dis 2024; 18:e0012464. [PMID: 39303001 DOI: 10.1371/journal.pntd.0012464] [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: 02/13/2024] [Accepted: 08/15/2024] [Indexed: 09/22/2024] Open
Abstract
BACKGROUND The transmission cycle of Schistosoma is remarkably complex, including sexual reproduction in human hosts and asexual reproduction in the intermediate host (freshwater snails). Patterns of rapid recrudescence after treatment and stable low transmission are often observed, hampering the achievement of control targets. Current mathematical models commonly assume regulation of transmission to occur at worm level through density-dependent egg production. However, conclusive evidence on this regulating mechanism is weak, especially for S. mansoni. In this study, we explore the interplay of different regulating mechanisms and their ability to explain observed patterns in S. mansoni epidemiology. METHODOLOGY/PRINCIPAL FINDINGS We developed SchiSTOP: a hybrid stochastic agent-based and deterministic modelling framework for S. mansoni transmission in an age-structured human population. We implemented different models with regulating mechanisms at: i) worm-level (density-dependent egg production), ii) human-level (anti-reinfection immunity), and iii) snail-level (density-dependent snail dynamics). Additionally, we considered two functional choices for the age-specific relative exposure to infection. We assessed the ability of each model to reproduce observed epidemiological patterns pre- and post-control, and compared successful models in their predictions of the impact of school-based and community-wide treatment. Simulations confirmed that assuming at least one regulating mechanism is required to reproduce a stable endemic equilibrium. Snail-level regulation was necessary to explain stable low transmission, while models combining snail- and human-level regulation with an age-exposure function informed with water contact data were successful in reproducing a rapid rebound after treatment. However, the predicted probability of reaching the control targets varied largely across models. CONCLUSIONS/SIGNIFICANCE The choice of regulating mechanisms in schistosomiasis modelling largely determines the expected impact of control interventions. Overall, this work suggests that reaching the control targets solely through mass drug administration may be more challenging than currently thought. We highlight the importance of regulating mechanisms to be included in transmission models used for policy.
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Affiliation(s)
- Veronica Malizia
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
- Radboud University Medical Center, Department IQ Health, Biostatistics Research Group, Nijmegen, The Netherlands
| | - Sake J de Vlas
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Kit C B Roes
- Radboud University Medical Center, Department IQ Health, Biostatistics Research Group, Nijmegen, The Netherlands
| | - Federica Giardina
- Radboud University Medical Center, Department IQ Health, Biostatistics Research Group, Nijmegen, The Netherlands
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Ndiour CN, Senghor B, Thiam O, Niang S, Wotodjo AN, Faye BT, Ndiaye NA, Sow O, Sylla K, Ndiaye M, Gaye O, Faye B, Sokhna C, Doucouré S, Sow D. Prevalence and associated factors of schistosomiasis among pregnant women in northern Senegal. BMC Infect Dis 2024; 24:682. [PMID: 38982383 PMCID: PMC11232235 DOI: 10.1186/s12879-024-09443-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/28/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND Schistosomiasis remains a public health concern worldwide. It is responsible for more than 240 million cases in 78 countries, 40 million of whom are women of childbearing age. In the Senegal River basin, both Schistosoma haematobium and Schistosoma mansoni are very prevalent in school-age children. However, there is a lack of information on the burden of schistosomiasis in pregnant women, which can cause complications in the pregnancy outcome. This study aimed to determine the prevalence and associated factors of schistosomiasis in pregnant women. METHODS We conducted a prospective cross-sectional study of pregnant women attending antenatal clinics at the health center of the Senegalese Sugar Company and at the hospital of Richard Toll between August and December 2021. The urine and stool samples collected were examined using microscopy techniques and quantitative polymerase chain reaction (qPCR) to detect the presence of S. haematobium and S. mansoni. The urines were previously tested using urine reagent strips to detect hematuria and proteinuria. Socio-demographical, clinical, and diagnostically data were recorded by the midwife and the gynaecologist. The data were analyzed using a logistic regression model. RESULTS Among the 298 women examined for the infection by microscopic, 65 (21.81%) were infected with urogenital schistosomiasis, 10 (3.36%) with intestinal schistosomiasis, and 4 (1.34%) were co-infected with both types of schistosomiasis. Out of the 288 samples tested by qPCR, 146 (48.99%) were positive for S. haematobium, 49 (35.51%) for S. mansoni and 22 (15.94%) for both species (co-infection). Pregnant women having microscopic haematuria and proteinuria were significantly more infected (p < 0.05). CONCLUSION This study has revealed a high prevalence of schistosomiasis in pregnant women in Senegal. The qPCR allowed us to detect more cases compared to the microscopy. There is a need to conduct more studies to understand the real burden of the disease and to set up a surveillance system to prevent pregnancy-related complications.
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Affiliation(s)
- Coumba Nar Ndiour
- Service de Parasitologie-Mycologie, UFR Sciences de la Santé, Université Gaston Berger, de Saint-Louis, Senegal
| | - Bruno Senghor
- EMR MINES: Maladies Infectieuses, Négligées et Émergentes au Sud, Institut de Recherche pour le Développement, Campus International Institut de Recherche pour le Développement-Université-Cheikh Anta Diop of Hann, BP 1386, Dakar, Sénégal
| | - Ousmane Thiam
- Service de Gynécologie-Obstétrique, UFR Sciences de la Santé, Université Gaston Berger, de Saint-Louis, Senegal
| | - Souleymane Niang
- Centre de Santé, Compagnie Sucrière Sénégalaise, Richard Toll, Richard Toll, Senegal
| | - Amélé Nyedzie Wotodjo
- EMR MINES: Maladies Infectieuses, Négligées et Émergentes au Sud, Institut de Recherche pour le Développement, Campus International Institut de Recherche pour le Développement-Université-Cheikh Anta Diop of Hann, BP 1386, Dakar, Sénégal
| | - Babacar Thiendella Faye
- Service de Parasitologie-Mycologie, UFR Sciences de la Santé, Université Gaston Berger, de Saint-Louis, Senegal
| | - Ndeye Amy Ndiaye
- Direction de la Santé de la Mère et de l'Enfant, Ministère de la Santé et de l'Action Sociale, Dakar, Senegal
| | - Omar Sow
- Service de Parasitologie-Mycologie, UFR Sciences de la Santé, Université Gaston Berger, de Saint-Louis, Senegal
| | - Khadime Sylla
- Service de Parasitologie-Mycologie, FMPO, Université Cheikh Anta Diop, de Dakar, Senegal
| | - Magatte Ndiaye
- Service de Parasitologie-Mycologie, FMPO, Université Cheikh Anta Diop, de Dakar, Senegal
| | - Oumar Gaye
- Service de Parasitologie-Mycologie, FMPO, Université Cheikh Anta Diop, de Dakar, Senegal
| | - Babacar Faye
- Service de Parasitologie-Mycologie, FMPO, Université Cheikh Anta Diop, de Dakar, Senegal
| | - Cheikh Sokhna
- EMR MINES: Maladies Infectieuses, Négligées et Émergentes au Sud, Institut de Recherche pour le Développement, Campus International Institut de Recherche pour le Développement-Université-Cheikh Anta Diop of Hann, BP 1386, Dakar, Sénégal
| | - Souleymane Doucouré
- EMR MINES: Maladies Infectieuses, Négligées et Émergentes au Sud, Institut de Recherche pour le Développement, Campus International Institut de Recherche pour le Développement-Université-Cheikh Anta Diop of Hann, BP 1386, Dakar, Sénégal
| | - Doudou Sow
- Service de Parasitologie-Mycologie, UFR Sciences de la Santé, Université Gaston Berger, de Saint-Louis, Senegal.
- EMR MINES: Maladies Infectieuses, Négligées et Émergentes au Sud, Institut de Recherche pour le Développement, Campus International Institut de Recherche pour le Développement-Université-Cheikh Anta Diop of Hann, BP 1386, Dakar, Sénégal.
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Duguay C, Mosha JF, Lukole E, Mangalu D, Thickstun C, Mallya E, Aziz T, Feng C, Protopopoff N, Mosha F, Manjurano A, Krentel A, Kulkarni MA. Assessing risk factors for malaria and schistosomiasis among children in Misungwi, Tanzania, an area of co-endemicity: A mixed methods study. PLOS GLOBAL PUBLIC HEALTH 2023; 3:e0002468. [PMID: 37992045 PMCID: PMC10664891 DOI: 10.1371/journal.pgph.0002468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 10/16/2023] [Indexed: 11/24/2023]
Abstract
Malaria and schistosomiasis are two major parasitic vector-borne diseases that are a particular threat to young children in Sub-Saharan Africa. In the present study, we investigated factors that are associated with malaria, schistosomiasis, and co-infection among school-aged children, using an explanatory sequential mixed-methods approach. A cross-sectional study was conducted in January 2022 in Misungwi, Tanzania, that sampled 1,122 children aged 5 to 14 years old for malaria and schistosomiasis infection. Mixed-effect logistic regression models were used to assess the association between infection prevalence or seroprevalence, and environmental determinants that create favorable conditions for vectors and parasites and social determinants that relate to disease exposure. Community mapping combined with direct field observations were conducted in August 2022 in three selected villages from the cross-sectional study to understand specific water use behaviors and to identify potential malaria mosquito larval breeding sites and freshwater snail habitat. The prevalence of malaria, seroprevalence of schistosomiasis, and co-infection in this study were 40.4%, 94.3%, and 38.1%, respectively. Individual-level factors emerged as the primary determinants driving the association with infection, with age (every one-year increase in age) and sex (boys vs girls) being statistically and positively associated with malaria, schistosomiasis, and co-infection (P<0.05 for all). Community maps identified many unimproved water sources in all three villages that were used by humans, cattle, or both. We found that children primarily fetched water, and that unprotected wells were dedicated for drinking water whereas ponds were dedicated for other domestic uses and cattle. Although not identified in the community maps, we found hand pumps in all three villages were not in use because of unpleasant taste and high cost. This study improves our understanding of individual, social and environmental factors that are associated with malaria, schistosomiasis, and co-infection, which can inform potential entry points for integrated disease prevention and control.
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Affiliation(s)
- Claudia Duguay
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Jacklin F. Mosha
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Eliud Lukole
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Doris Mangalu
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Charles Thickstun
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
| | - Elizabeth Mallya
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Tatu Aziz
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Cindy Feng
- Department of Community Health & Epidemiology, Dalhousie University, Halifax, Canada
| | - Natacha Protopopoff
- Faculty of Infectious and Tropical Diseases, Disease Control Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Franklin Mosha
- Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Alphaxard Manjurano
- National Institute of Medical Research Tanzania, Mwanza Research Centre, Mwanza, Tanzania
| | - Alison Krentel
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
- Bruyère Research Institute, Ottawa, Ontario, Canada
| | - Manisha A. Kulkarni
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, Canada
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Linsuke S, Ilombe G, Disonama M, Nzita JD, Mbala P, Lutumba P, Van Geertruyden JP. Schistosoma Infection Burden and Risk Factors among School-Aged Children in a Rural Area of the Democratic Republic of the Congo. Trop Med Infect Dis 2023; 8:455. [PMID: 37755916 PMCID: PMC10535068 DOI: 10.3390/tropicalmed8090455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/28/2023] Open
Abstract
Despite continuous efforts to control schistosomiasis (SCH) in the Democratic Republic of the Congo (DRC), it still poses a significant challenge. In order to enhance control measures, additional research is necessary. This study documents the burden of SCH infection and its predictors in a rural area of the DRC. We conducted a household cross-sectional study from June to August 2021 among 480 school-aged children (SAC) aged 5-15 years living in a rural area of Kisangi, in the southwest DRC. We collected and examined stool, urine, and blood samples of each child. Additionally, we obtained data on anthropometry, socio-demographics, household information, and individual water contact behaviors. The overall prevalence of SCH infection was 55.8% (95% CI: 51.4-60.3), with prevalences of 41% (95% CI: 36.6-45.5), 36.3% (95% CI: 31.9-40.6), and 38.4% (95% CI: 32.6-44.3) for S. haematobium and S. mansoni infections and both infections, respectively. Among those with SCH infection, most had a light (67.5%) or heavy (51.7%) infection intensity. The geometric mean egg count was 16.6 EP 10 mL (95% CI: 12.9-21.3) for S. haematobium and 390.2 EPG (95% CI: 300.2-507.3) for S. mansoni. However, age (10 years and above (aOR: 2.1; 95% CI: 1.5-3.1; p < 0.001)) was an independent risk factor for SCH infection. The overall prevalence of malaria infection was 16.9% (95% CI: 13.5-20.2), that of stunting was 28.7% (95% CI: 24.7-32.8), that of underweight was 17.1% (95% CI: 12.8-21.4), and that of thinness was 7.1% (95% CI: 4.8-9.4). Anemia was prevalent at 49.4% (95% CI: 44.9-5), and the median Hb level of all participants was 11.6 g/dL (IQR: 10.5-12.6 g/dL). Anemia was strongly associated with SCH infection (aOR: 3.4; 95% CI: 2.3-5.1; p < 0.001) yet there was no association with the risk for malaria infection (aOR: 1.0; 95% CI: 0.6-1.8; p = 0.563). In addition, the risk of anemia increased with heavy infection intensities (p < 0.026 and p < 0.013 for S. haematobium and S. mansoni, respectively). However, stunting had a protective factor for anemia (aOR: 0.3; 95% CI: 0.2-0.4; p < 0.001). To conclude, SCH infection was widespread among the SAC and strongly linked to anemia. These results provide evidence of the hyperendemicity of infection in the study area, which requires preventative measures such as chemotherapy to reduce the schistosomiasis-associated morbidity, and micronutrient supplements to avoid anemia.
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Affiliation(s)
- Sylvie Linsuke
- Department of Epidemiology, National Institute of Biomedical Research (INRB), Kinshasa 01015, Democratic Republic of the Congo;
- Global Health Institute, Faculty of Medicine, University of Antwerp, 2000 Antwerp, Belgium; (G.I.); (J.-P.V.G.)
| | - Gillon Ilombe
- Global Health Institute, Faculty of Medicine, University of Antwerp, 2000 Antwerp, Belgium; (G.I.); (J.-P.V.G.)
- Department of Parasitology, National Institute of Biomedical Research (INRB), Kinshasa 01015, Democratic Republic of the Congo
| | - Michel Disonama
- Health Zone of Kwilu-Ngongo, Kongo-Central Province, Kwilu-Ngongo 20, Democratic Republic of the Congo; (M.D.); (J.D.N.)
| | - Jean Deny Nzita
- Health Zone of Kwilu-Ngongo, Kongo-Central Province, Kwilu-Ngongo 20, Democratic Republic of the Congo; (M.D.); (J.D.N.)
| | - Placide Mbala
- Department of Epidemiology, National Institute of Biomedical Research (INRB), Kinshasa 01015, Democratic Republic of the Congo;
- Department of Virology, University of Kinshasa, Kinshasa 01015, Democratic Republic of the Congo
| | - Pascal Lutumba
- Department of Tropical Medicine, University of Kinshasa, Kinshasa 01015, Democratic Republic of the Congo;
| | - Jean-Pierre Van Geertruyden
- Global Health Institute, Faculty of Medicine, University of Antwerp, 2000 Antwerp, Belgium; (G.I.); (J.-P.V.G.)
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Reitzug F, Ledien J, Chami GF. Associations of water contact frequency, duration, and activities with schistosome infection risk: A systematic review and meta-analysis. PLoS Negl Trop Dis 2023; 17:e0011377. [PMID: 37315020 DOI: 10.1371/journal.pntd.0011377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 05/12/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Schistosomiasis is a water-borne parasitic disease which affects over 230 million people globally. The relationship between contact with open freshwater bodies and the likelihood of schistosome infection remains poorly quantified despite its importance for understanding transmission and parametrising transmission models. METHODS We conducted a systematic review to estimate the average effect of water contact duration, frequency, and activities on schistosome infection likelihood. We searched Embase, MEDLINE (including PubMed), Global Health, Global Index Medicus, Web of Science, and the Cochrane Central Register of Controlled Trials from inception until May 13, 2022. Observational and interventional studies reporting odds ratios (OR), hazard ratios (HR), or sufficient information to reconstruct effect sizes on individual-level associations between water contact and infection with any Schistosoma species were eligible for inclusion. Random-effects meta-analysis with inverse variance weighting was used to calculate pooled ORs and 95% confidence intervals (CIs). RESULTS We screened 1,411 studies and included 101 studies which represented 192,691 participants across Africa, Asia, and South America. Included studies mostly reported on water contact activities (69%; 70/101) and having any water contact (33%; 33/101). Ninety-six percent of studies (97/101) used surveys to measure exposure. A meta-analysis of 33 studies showed that individuals with water contact were 3.14 times more likely to be infected (OR 3.14; 95% CI: 2.08-4.75) when compared to individuals with no water contact. Subgroup analyses showed that the positive association of water contact with infection was significantly weaker in children compared to studies which included adults and children (OR 1.67; 95% CI: 1.04-2.69 vs. OR 4.24; 95% CI: 2.59-6.97). An association of water contact with infection was only found in communities with ≥10% schistosome prevalence. Overall heterogeneity was substantial (I2 = 93%) and remained high across all subgroups, except in direct observation studies (I2 range = 44%-98%). We did not find that occupational water contact such as fishing and agriculture (OR 2.57; 95% CI: 1.89-3.51) conferred a significantly higher risk of schistosome infection compared to recreational water contact (OR 2.13; 95% CI: 1.75-2.60) or domestic water contact (OR 1.91; 95% CI: 1.47-2.48). Higher duration or frequency of water contact did not significantly modify infection likelihood. Study quality across analyses was largely moderate or poor. CONCLUSIONS Any current water contact was robustly associated with schistosome infection status, and this relationship held across adults and children, and schistosomiasis-endemic areas with prevalence greater than 10%. Substantial gaps remain in published studies for understanding interactions of water contact with age and gender, and the influence of these interactions for infection likelihood. As such, more empirical studies are needed to accurately parametrise exposure in transmission models. Our results imply the need for population-wide treatment and prevention strategies in endemic settings as exposure within these communities was not confined to currently prioritised high-risk groups such as fishing populations.
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Affiliation(s)
- Fabian Reitzug
- Big Data Institute, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Julia Ledien
- Big Data Institute, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Goylette F Chami
- Big Data Institute, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
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Senghor B, Mathieu-Begné E, Rey O, Doucouré S, Sow D, Diop B, Sène M, Boissier J, Sokhna C. Urogenital schistosomiasis in three different water access in the Senegal river basin: prevalence and monitoring praziquantel efficacy and re-infection levels. BMC Infect Dis 2022; 22:968. [PMID: 36581796 PMCID: PMC9801593 DOI: 10.1186/s12879-022-07813-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 10/26/2022] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Urogenital schistosomiasis is a neglected tropical disease most prevalent in sub-Saharan Africa. In the Senegal river basin, the construction of the Diama dam led to an increase and endemicity of schistosomiasis. Since 2009, praziquantel has frequently been used as preventive chemotherapy in the form of mass administration to Senegalese school-aged children without monitoring of the treatment efficacy and the prevalence after re-infection. This study aims to determine the current prevalence of urogenital schistosomiasis (caused by Schistosoma haematobium), the efficacy of praziquantel, and the re-infection rates in children from five villages with different water access. METHODS The baseline prevalence of S. haematobium was determined in August 2020 in 777 children between 5 and 11 years old and a single dose of praziquantel (40 mg/kg) was administered to those positive. The efficacy of praziquantel and the re-infection rates were monitored 4 weeks and 7 months after treatment, respectively, in 226 children with a high intensity of infection at baseline. RESULTS At the baseline, prevalence was low among children from the village of Mbane who live close to the Lac de Guiers (38%), moderate among those from the villages of Dioundou and Khodit, which neighbor the Doue river (46%), and very high at Khodit (90.6%) and Guia (91.2%) which mainly use an irrigation canal. After treatment, the observed cure rates confirmed the efficacy of praziquantel. The lowest cure rate (88.5%) was obtained in the village using the irrigation canal, while high cure rates were obtained in those using the lake (96.5%) and the river (98%). However, high egg reduction rates (between 96.7 and 99.7%) were obtained in all the villages. The re-infection was significantly higher in the village using the canal (42.5%) than in the villages accessing the Lac de Guiers (18.3%) and the Doue river (14.8%). CONCLUSION Praziquantel has an impact on reducing the prevalence and intensity of urogenital schistosomiasis. However, in the Senegal river basin, S. haematobium remains a real health problem for children living in the villages near the irrigation canals, despite regular treatment, while prevalence is declining from those frequenting the river and the Lac de Guiers. Trial registration ClinicalTrials.gov, NCT04635553. Registered 19 November 2020 retrospectively registered, https://www. CLINICALTRIALS gov/ct2/show/NCT04635553?cntry=SN&draw=2&rank=4.
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Affiliation(s)
- Bruno Senghor
- grid.418291.70000 0004 0456 337XCampus International IRD-UCAD de Hann, Vectors-Tropical and Mediterranean Infections (VITROME) Laboratory, 1386 Dakar, Senegal
| | - Eglantine Mathieu-Begné
- grid.121334.60000 0001 2097 0141Host Pathogen Environments Interactions (IHPE) Laboratory, CNRS, IFREMER, University of Montpellier, University of Perpignan via Domitia, Perpignan, France
| | - Olivier Rey
- grid.121334.60000 0001 2097 0141Host Pathogen Environments Interactions (IHPE) Laboratory, CNRS, IFREMER, University of Montpellier, University of Perpignan via Domitia, Perpignan, France
| | - Souleymane Doucouré
- grid.418291.70000 0004 0456 337XCampus International IRD-UCAD de Hann, Vectors-Tropical and Mediterranean Infections (VITROME) Laboratory, 1386 Dakar, Senegal
| | - Doudou Sow
- grid.442784.90000 0001 2295 6052Department of Parasitology-Mycology, UFR of Health Sciences, University Gaston Berger, 234, Saint-Louis, Senegal
| | - Bocar Diop
- grid.442784.90000 0001 2295 6052Laboratory of Biological and Agronomic Sciences and Modelling of Complex Systems, UFRS2ATA, Gaston Berger University of Saint-Louis, Saint-Louis, Senegal
| | - Mariama Sène
- National Schistosomiasis Control Program (NSCP), Ministry of Health, Dakar, Senegal
| | - Jérôme Boissier
- grid.121334.60000 0001 2097 0141Host Pathogen Environments Interactions (IHPE) Laboratory, CNRS, IFREMER, University of Montpellier, University of Perpignan via Domitia, Perpignan, France
| | - Cheikh Sokhna
- grid.418291.70000 0004 0456 337XCampus International IRD-UCAD de Hann, Vectors-Tropical and Mediterranean Infections (VITROME) Laboratory, 1386 Dakar, Senegal ,grid.5399.60000 0001 2176 4817VITROME, IRD, SSA, AP-HM, IHU-Mediterranean Infection, Aix-Marseille Univ, Marseille, France
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Ghazy RM, Ellakany WI, Badr MM, Taktak NEM, Elhadad H, Abdo SM, Hagag A, Hussein AR, Tahoun MM. Determinants of Schistosoma mansoni transmission in hotspots at the late stage of elimination in Egypt. Infect Dis Poverty 2022; 11:102. [PMID: 36138424 PMCID: PMC9503191 DOI: 10.1186/s40249-022-01026-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/25/2022] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND In certain settings, the prevalence and severity of schistosoma infection do not lessen despite repeated rounds of preventative chemotherapy; these areas are known as hotspots. This study aimed to investigate the role of human practices, besides environmental and malacological factors, in the maintenance of the Schistosoma mansoni infection transmission chain in hotspot areas in Egypt. METHODS This cross-sectional study was conducted between July and November 2019 in Kafr El-Sheikh Governorate, Egypt. A pre-designed structured interviewing questionnaire was used to collect humanitarian data. Stool samples were collected from children aged 6-15 years on three successive days and examined using the Kato-Katz technique. Simultaneously, water and snail samples were taken from watercourses surrounding houses. Snails were identified based on their shell morphology and structure and tested for cercaria shedding. Water samples were analyzed for their physicochemical and biological characteristics. RESULTS A total of 2259 fecal samples (1113 in summer and 1146 in fall) were collected from 861 children. About 46.9% of the participants were males, and 31.8% were aged 6-10 years. The prevalence of S. mansoni infection was higher during the summer than during the fall (19.1% vs 7.2%, respectively, P < 0.01). The intensity of infection (light, moderate, and heavy) during summer versus fall was (93.55 vs 89.38%, 6.45 vs 8.85%, and 0.00% vs 1.77%), respectively (P < 0.05). A higher prevalence of human infection was observed among males than females [OR = 1.63, 95% confidence interval (CI):1.10-2.40, P = 0.015], children aged 11-15 years than among their counterparts aged 6-10 years (OR = 2.96, 95% CI: 1.72-5.06, P < 0.001), and mothers with a low level of education (OR = 3.33, 95% CI: 1.70-6.52, P < 0.001). The main identified risk factors were contacting the main body of water-canal for washing clothes (OR = 1.81, 95% CI: 1.12-2.49, P = 0.015), land irrigation (OR = 2.56, 95% CI: 1.32-4.96, P = 0.004), water collection (OR = 2.94, 95% CI: 1.82-4.73, P < 0.001), bathing (OR = 2.34, 95% CI: 1.21-4.31, P = 0.009), and garbage disposal (OR = 2.38, 95% CI:1.38-4.12, P < 0.001). The count of Biomphalaria alexandrina was distinct between seasons (P < 0.01) in consistent with statistically significant differences in water temperature, salinity, turbidity, the total concentration of coliforms, depth, velocity, and water level (P < 0.01). The presence of grasses and duckweeds was significantly associated with snail infection (P = 0.00 l). Significant effects of water depth, pH, temperature, and total dissolved solids on snail count were also observed (P < 0.05). CONCLUSIONS The persistence of the infection is due to adoption of risky behaviors and environmental factors that enhance snail survival and infection. Schistosomiasis elimination in hotspots requires an integrated control approach that combines preventive chemotherapy with other complementary measures.
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Affiliation(s)
- Ramy Mohamed Ghazy
- grid.7155.60000 0001 2260 6941Tropical Health Department, High Institute of Public Health, Alexandria University, Alexandria, Egypt
| | - Walid Ismail Ellakany
- grid.7155.60000 0001 2260 6941Department of Tropical Medicine, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mai M. Badr
- grid.7155.60000 0001 2260 6941Department of Environmental Health, High Institute of Public Health Alexandria University, Alexandria, Egypt
| | - Nehad E. M. Taktak
- grid.7155.60000 0001 2260 6941Department of Environmental Health, High Institute of Public Health Alexandria University, Alexandria, Egypt
| | - Heba Elhadad
- grid.7155.60000 0001 2260 6941Parasitology Department, Medical Research Institute, Alexandria university, Alexandria, Egypt
| | - Sarah M. Abdo
- grid.411978.20000 0004 0578 3577Department of Medical Parasitology, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, 35516 Egypt
| | - Ayat Hagag
- grid.411978.20000 0004 0578 3577Department of Medical Parasitology, Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, 35516 Egypt
| | | | - Mohamed Mostafa Tahoun
- grid.7155.60000 0001 2260 6941Department of Epidemiology, High Institute of Public Health Alexandria University, Alexandria, Egypt
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Falcone B, Park S, Wu HW, Leenstra T, Jiz MA, Jarilla B, McGarvey ST, Kurtis JD, Friedman JF. Comparison of self-reported and observed water contact measures in Schistosoma japonicum-endemic villages in Leyte, The Philippines. Trans R Soc Trop Med Hyg 2022; 116:433-439. [PMID: 34634127 PMCID: PMC9070479 DOI: 10.1093/trstmh/trab149] [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: 01/12/2021] [Revised: 08/08/2021] [Accepted: 09/13/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We compared individuals' self-reported water contact from a questionnaire to direct observation of water contact. Questionnaires that accurately capture water contact are necessary to risk-stratify individuals and communities at high risk for schistosomiasis. METHODS Individuals (N=677) ages 7-30 y were included from three Schistosoma japonicum-endemic villages in Leyte, The Philippines. Each individual was observed for 12 d over the course of the 18-month study and the questionnaire was administered six times. A questionnaire index was derived that captured the number of self-reported contacts with water bodies for any purpose. An exposure index was created based on the sum of contacts that was weighted by the percentage of body surface area (BSA) exposed and exposure duration. RESULTS Of 16 water contact activities, only bathing and washing clothes exhibited a significant, positive correlation between self-reported contacts and the observed exposure index related to those contacts. CONCLUSIONS We found that only the reported frequencies of bathing and washing clothes were significantly related to an individual's overall observed exposure index, while use of all reported contacts was not related to the observed exposure. This study further supports the need for questionnaires to be augmented by some measure of how much BSA is exposed and/or time is spent in the water on average for a specific activity.
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Affiliation(s)
- Bianca Falcone
- Center for International Health Research, 55 Claverick Street, Providence, RI 02903, USA
| | - Sangshin Park
- Graduate School of Urban Public Health & Department of Urban Big Data Convergence, University of Seoul, Seoul, Republic of Korea, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 02504, Republic of Korea
| | - Hannah W Wu
- Center for International Health Research, 55 Claverick Street, Providence, RI 02903, USA
| | - Tjalling Leenstra
- Centre for Infectious Diseases, Epidemiology and Surveillance, National Institute for Public Health and the Environment, Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, The Netherlands
| | - Mario A Jiz
- Research Institute for Tropical Medicine, Department of Immunology, 9002 Research Drive, Filinvest Corporate City, Alabang Muntinlupa City, Metro Manila Philippines, 1781
| | - Blanca Jarilla
- Research Institute for Tropical Medicine, Department of Immunology, 9002 Research Drive, Filinvest Corporate City, Alabang Muntinlupa City, Metro Manila Philippines, 1781
| | - Stephen T McGarvey
- Brown University School of Public Health, International Health Institute, Box G-S121 121 South Main Street Providence, RI 02912, USA
| | - Jonathan D Kurtis
- Center for International Health Research, 55 Claverick Street, Providence, RI 02903, USA
| | - Jennifer F Friedman
- Center for International Health Research, 55 Claverick Street, Providence, RI 02903, USA
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Botai CM, Botai JO, Murambadoro M, Zwane NN, Adeola AM, de Wit JP, Adisa OM. Scope, trends and opportunities for socio-hydrology research in Africa: A bibliometric analysis. S AFR J SCI 2022. [DOI: 10.17159/sajs.2022/8742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Socio-hydrology research is concerned with the understanding of how humanity interacts with water resources. The purpose of this study was to assess the disparity between global and African trends as well as developments in the research domain of socio-hydrology. From the viewpoint of a multitude of research themes, multi-author collaborations between African and international researchers and the number of publications produced globally, the results reveal that the field of socio-hydrology is still underdeveloped and yet nascent. At a global level, the USA, China, and the Netherlands have the highest number of scientific publications, while in Africa, South Africa dominates, although these scientific publications are significantly much lower than the global output. The output of scientific publications on socio-hydrology research from Africa increased from 2016, with significant output reached in 2019. Water management and supply, hydrological modelling, flood monitoring as well as policies and decision-making, are some of the dominant themes found through keywords co-occurrence analysis. These main keywords may be considered as the foci of research in socio-hydrology. Although socio-hydrology research is still in the early stages of development in Africa, the cluster and emerging themes analysis provide opportunities for research in Africa that will underpin new frontiers of the research agenda encompassing topics such as the (1) impacts of climate change on socio-hydrology; (2) influence of socio-hydrology on water resources such as surface water and groundwater; (3) benefits of socio-hydrological models on river basins and (4) role of socio-hydrology in economic sectors such as agriculture. Overall, this study points to a need to advance socio-hydrology research in Africa in a bid to address pressing water crises that affect sustainable development as well as to understand the feedback mechanisms and linkages between water resources and different sectors of society.
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Affiliation(s)
| | - Joel O. Botai
- South African Weather Service, Pretoria, South Africa
- Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, South Africa
- Department of Information Technology, Central University of Technology, Bloemfontein, South Africa
| | - Miriam Murambadoro
- South African Weather Service, Pretoria, South Africa
- Global Change Institute, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Abiodun M. Adeola
- South African Weather Service, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | | | - Omolola M. Adisa
- Department of Information Technology, Central University of Technology, Bloemfontein, South Africa
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Gender-related differences in prevalence, intensity and associated risk factors of Schistosoma infections in Africa: A systematic review and meta-analysis. PLoS Negl Trop Dis 2021; 15:e0009083. [PMID: 34788280 PMCID: PMC8635327 DOI: 10.1371/journal.pntd.0009083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 12/01/2021] [Accepted: 09/29/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Schistosomiasis remains a global-health problem with over 90% of its burden concentrated in Africa. Field studies reflect the complex ways in which socio-cultural and socio-economic variables, affect the distribution of Schistosoma infections across different populations. This review set out to systematically investigate and quantify the differences in Schistosoma infection burdens between males and females in Africa for two of the most prevalent Schistosoma species-Schistosoma mansoni and Schistosoma haematobium. METHODOLOGY We searched (from inception to 11th March 2020) Embase, MEDLINE, PubMed, and Web of Science for relevant studies on schistosomiasis. We included studies that report S. mansoni and/or S. haematobium prevalence and/or intensity data distributed between males and females. We conducted meta-analyses on the male to female (M:F) prevalence of infection ratios. Subgroup analyses were performed according to study baseline prevalence, sample size and the lower and upper age limit of study participants. We also present a descriptive analysis of differential risk and intensity of infection across males and females. Evidence for differences in the prevalence of schistosomiasis infection between males and females is presented, stratified by Schistosoma species. RESULT We identified 128 relevant studies, with over 200,000 participants across 23 countries. Of all the reported differences in the prevalence of infection between males and females, only 41% and 34% were statistically significant for S. mansoni and S. haematobium, respectively. Similar proportions of studies (27% and 34% for for S. haematobium and S. mansoni, respectively) of the reported differences in intensity of infection between males and females were statistically significant. The meta-analyses summarized a higher prevalence of infection in males; pooled random-effects weighted M:F prevalence of infection ratios were 1.20 (95% CI 1.11-1.29) for S. haematobium and 1.15 (95% CI 1.08-1.22) for S. mansoni. However, females are underrespresented in some of the studies. Additionally, there was significant heterogeneity across studies (Higgins I2 statistic (p-values < 0.001, I2values>95%)). Results of the subgroup analysis showed that the baseline prevalence influenced the M:F prevalence ratios for S. haematobium and S. mansoni, with higher M:F prevalence of infection ratios in settings with a lower baseline prevalence of infection. Across the studies, we identified four major risk factors associated with infection rates: occupational and recreational water contact, knowledge, socio-economic factors and demographic factors. The effect of these risk factors on the burden of infection in males and females varied across studies. CONCLUSIONS We find evidence of differences in prevalence of infection between males and females which may reflect differences in gender norms and water contact activities, suggesting that policy changes at the regional level may help ameliorate gender-related disparities in schistosomiasis infection burden. Collecting, robustly analysing, and reporting, sex-disaggregated epidemiological data, is currently lacking, but would be highly informative for planning effective treatment programmes and establishing those most at risk of schistosomiasis infections.
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11
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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: 5] [Impact Index Per Article: 1.7] [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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Lund AJ, Sokolow SH, Jones IJ, Wood CL, Ali S, Chamberlin A, Sy AB, Sam MM, Jouanard N, Schacht AM, Senghor S, Fall A, Ndione R, Riveau G, De Leo GA, López-Carr D. Exposure, hazard, and vulnerability all contribute to Schistosoma haematobium re-infection in northern Senegal. PLoS Negl Trop Dis 2021; 15:e0009806. [PMID: 34610025 PMCID: PMC8525765 DOI: 10.1371/journal.pntd.0009806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 10/19/2021] [Accepted: 09/10/2021] [Indexed: 11/19/2022] Open
Abstract
Background Infectious disease risk is driven by three interrelated components: exposure, hazard, and vulnerability. For schistosomiasis, exposure occurs through contact with water, which is often tied to daily activities. Water contact, however, does not imply risk unless the environmental hazard of snails and parasites is also present in the water. By increasing reliance on hazardous activities and environments, socio-economic vulnerability can hinder reductions in exposure to a hazard. We aimed to quantify the contributions of exposure, hazard, and vulnerability to the presence and intensity of Schistosoma haematobium re-infection. Methodology/Principal findings In 13 villages along the Senegal River, we collected parasitological data from 821 school-aged children, survey data from 411 households where those children resided, and ecological data from all 24 village water access sites. We fit mixed-effects logistic and negative binomial regressions with indices of exposure, hazard, and vulnerability as explanatory variables of Schistosoma haematobium presence and intensity, respectively, controlling for demographic variables. Using multi-model inference to calculate the relative importance of each component of risk, we found that hazard (Ʃwi = 0.95) was the most important component of S. haematobium presence, followed by vulnerability (Ʃwi = 0.91). Exposure (Ʃwi = 1.00) was the most important component of S. haematobium intensity, followed by hazard (Ʃwi = 0.77). Model averaging quantified associations between each infection outcome and indices of exposure, hazard, and vulnerability, revealing a positive association between hazard and infection presence (OR = 1.49, 95% CI 1.12, 1.97), and a positive association between exposure and infection intensity (RR 2.59–3.86, depending on the category; all 95% CIs above 1) Conclusions/Significance Our findings underscore the linkages between social (exposure and vulnerability) and environmental (hazard) processes in the acquisition and accumulation of S. haematobium infection. This approach highlights the importance of implementing both social and environmental interventions to complement mass drug administration. While the impacts of natural hazards tend to be described in terms of social determinants such as exposure and vulnerability, the risk for infectious disease is often expressed in terms of environmental determinants without fully considering the socio-ecological processes that put people in contact with infective agents of disease. In the case of schistosomiasis, risk is determined by human interactions with freshwater environments where schistosome parasites circulate between people and aquatic snails. In this study, we quantified the relative contributions of exposure, hazard, and vulnerability to schistosome re-infection among schoolchildren in an endemic region of northern Senegal. We find that hazard and vulnerability influence whether a child becomes infected, while exposure and hazard influence the burden of worms once infection is acquired. Increasing numbers of worms is known to be positively associated with increasing severity of disease. Our findings underscore the importance of evaluating social and environmental determinants of disease simultaneously; omitting measures of exposure, hazard or vulnerability may limit our understanding of risk.
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Affiliation(s)
- Andrea J. Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Susanne H. Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Isabel J. Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Chelsea L. Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Sofia Ali
- Stanford University, Stanford, California, United States of America
| | - Andrew Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Alioune Badara Sy
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - M. Moustapha Sam
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Nicolas Jouanard
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- Station d’Innovation Aquacole, Saint Louis, Sénégal
| | - Anne-Marie Schacht
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- University of Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France
| | - Simon Senghor
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Assane Fall
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Raphael Ndione
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
| | - Gilles Riveau
- Centre de Recherche Biomédicale–Espoir Pour La Sante, Saint Louis, Sénégal
- University of Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France
| | - Giulio A. De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
- Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - David López-Carr
- Department of Geography, University of California, Santa Barbara, CA, United States of America
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Jones IJ, Sokolow SH, Chamberlin AJ, Lund AJ, Jouanard N, Bandagny L, Ndione R, Senghor S, Schacht AM, Riveau G, Hopkins SR, Rohr JR, Remais JV, Lafferty KD, Kuris AM, Wood CL, De Leo G. Schistosome infection in Senegal is associated with different spatial extents of risk and ecological drivers for Schistosoma haematobium and S. mansoni. PLoS Negl Trop Dis 2021; 15:e0009712. [PMID: 34570777 PMCID: PMC8476036 DOI: 10.1371/journal.pntd.0009712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/06/2021] [Indexed: 11/17/2022] Open
Abstract
Schistosome parasites infect more than 200 million people annually, mostly in sub-Saharan Africa, where people may be co-infected with more than one species of the parasite. Infection risk for any single species is determined, in part, by the distribution of its obligate intermediate host snail. As the World Health Organization reprioritizes snail control to reduce the global burden of schistosomiasis, there is renewed importance in knowing when and where to target those efforts, which could vary by schistosome species. This study estimates factors associated with schistosomiasis risk in 16 villages located in the Senegal River Basin, a region hyperendemic for Schistosoma haematobium and S. mansoni. We first analyzed the spatial distributions of the two schistosomes’ intermediate host snails (Bulinus spp. and Biomphalaria pfeifferi, respectively) at village water access sites. Then, we separately evaluated the relationships between human S. haematobium and S. mansoni infections and (i) the area of remotely-sensed snail habitat across spatial extents ranging from 1 to 120 m from shorelines, and (ii) water access site size and shape characteristics. We compared the influence of snail habitat across spatial extents because, while snail sampling is traditionally done near shorelines, we hypothesized that snails further from shore also contribute to infection risk. We found that, controlling for demographic variables, human risk for S. haematobium infection was positively correlated with snail habitat when snail habitat was measured over a much greater radius from shore (45 m to 120 m) than usual. S. haematobium risk was also associated with large, open water access sites. However, S. mansoni infection risk was associated with small, sheltered water access sites, and was not positively correlated with snail habitat at any spatial sampling radius. Our findings highlight the need to consider different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes. Schistosome parasites infect more than 200 million people worldwide, mainly in sub-Saharan Africa, where many people are at-risk for infection by multiple schistosome species simultaneously. To reduce the global burden of schistosomiasis, control of the parasites’ intermediate host–specific species of freshwater snails–has been elevated in priority to complement mass drug administration campaigns in endemic areas. To maximize the efficacy and efficiency of snail control efforts, a better understanding of where to target intermediate host snails is badly needed. This includes a better understanding of the spatial scale at which snails in the environment contribute to human infection risk, and, in co-endemic settings, how ecological determinants of infection risk vary by schistosome species. We used quantitative snail sampling and remotely-sensed data at 16 villages in the Senegal River Basin to compare and contrast ecological correlates and spatial scales of infection risk from freshwater snails that transmit Schistosoma haematobium versus S. mansoni. We found that infection risk for S. haematobium was associated with snail habitat at a larger spatial radius than is typically considered for schistosomiasis monitoring and control, whereas infection risk for S. mansoni was not positively correlated with snail habitat at any spatial sampling radius, but was associated with small water access sites enclosed by emergent vegetation. Our findings highlight the need to consider the different ecological and environmental factors driving the transmission of each schistosome species in co-endemic landscapes.
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Affiliation(s)
- Isabel J Jones
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Susanne H Sokolow
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America.,Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
| | - Andrew J Chamberlin
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Andrea J Lund
- Emmett Interdisciplinary Program in Environment and Resources, Stanford University, Stanford, California, United States of America
| | - Nicolas Jouanard
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Station d'Innovation Aquacole, Saint-Louis, Senegal
| | | | | | - Simon Senghor
- Biomedical Research Center EPLS, Saint-Louis, Senegal
| | - Anne-Marie Schacht
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Gilles Riveau
- Biomedical Research Center EPLS, Saint-Louis, Senegal.,Université Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, Lille, France
| | - Skylar R Hopkins
- National Center for Ecological Analysis and Synthesis, Santa Barbara, California, United States of America.,Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Jason R Rohr
- Department of Biological Science, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Justin V Remais
- Division of Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, United States of America
| | - Kevin D Lafferty
- Western Ecological Research Center, United States Geological Survey at Marine Science Institute, University of California, Santa Barbara, California, United States of America
| | - Armand M Kuris
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, California, United States of America
| | - Chelsea L Wood
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington, United States of America
| | - Giulio De Leo
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America.,Stanford Woods Institute for the Environment, Stanford University, Stanford, California, United States of America
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Mazigo HD, Samson A, Lambert VJ, Kosia AL, Ngoma DD, Murphy R, Matungwa DJ. "We know about schistosomiasis but we know nothing about FGS": A qualitative assessment of knowledge gaps about female genital schistosomiasis among communities living in Schistosoma haematobium endemic districts of Zanzibar and Northwestern Tanzania. PLoS Negl Trop Dis 2021; 15:e0009789. [PMID: 34591872 PMCID: PMC8509863 DOI: 10.1371/journal.pntd.0009789] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/12/2021] [Accepted: 09/03/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Schistosoma haematobium causes urogenital schistosomiasis and is widely distributed in Tanzania. In girls and women, the parasite can cause Female Genital Schistosomiasis (FGS), a gynecological manifestation of schistosomiasis that is highly neglected and overlooked by public health professionals and policy makers. This study explored community members' knowledge, attitudes and perceptions (KAP) on and health seeking behavior for FGS. METHODS/PRINCIPAL FINDINGS Using qualitative research methods-including 40 Focus Group Discussions (FGDs) and 37 Key Informant Interviews (KIIs)-we collected data from 414 participants (Males n = 204 [49.3%] and Females n = 210 [50.7%]). The study engaged 153 participants from Zanzibar and 261 participants from northwestern Tanzania and was conducted in twelve (12) purposively selected districts (7 districts in Zanzibar and 5 districts in northwestern Tanzania). Most participants were aware of urogenital schistosomiasis. Children were reported as the most affected group and blood in urine was noted as a common symptom especially in boys. Adults were also noted as a risk group due to their involvement in activities like paddy farming that expose them to infection. Most participants lacked knowledge of FGS and acknowledged having no knowledge that urogenital schistosomiasis can affect the female reproductive system. A number of misconceptions on the symptoms of FGS and how it is transmitted were noted. Adolescent girls and women presenting with FGS related symptoms were reported to be stigmatized, perceived as having a sexually transmitted infection (STI), and sometimes labeled as "prostitutes". Health seeking behavior for FGS included a combination of traditional medicine, self-treatment and modern medicine. CONCLUSION/SIGNIFICANCE Community members living in two very different areas of Tanzania exhibited major, similar gaps in knowledge about FGS. Our data illustrate a critical need for the national control program to integrate public health education about FGS during the implementation of school- and community-based mass drug administration (MDA) programs and the improvement of water, sanitation and hygiene (WASH) facilities.
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Affiliation(s)
- Humphrey D. Mazigo
- Department of Parasitology and Entomology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Anna Samson
- Department of Behavioral Sciences, School of Public Health, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Valencia J. Lambert
- Center for Global Health, Weill Cornell Medicine, New York City, New York, United States of America
| | - Agnes L. Kosia
- School of Nursing, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Deogratias D. Ngoma
- Accelerating the Sustainable Control and Elimination of Neglected Tropical Diseases—Crown Agents, London, United Kingdom
| | | | - Dunstan J. Matungwa
- Department of Sexual and Reproductive Health, National Institute for Medical Research, Mwanza, Tanzania
- Department of Anthropology, School of Arts and Sciences, Rutgers University, New Brunswick, New Jersey, United States of America
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15
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Bezerra DVF, Queiroz JW, Câmara VAV, Maciel BLL, Nascimento ELT, Jerônimo SMB. Factors Associated with Schistosoma mansoni Infestation in Northeast Brazil: A Need to Revisit Individual and Community Risk Factors. Am J Trop Med Hyg 2021; 104:1404-1411. [PMID: 33591939 DOI: 10.4269/ajtmh.19-0513] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 05/20/2020] [Indexed: 11/07/2022] Open
Abstract
In Brazil, schistosomiasis continues to be an important health issue. The aim of this study was to identify factors associated with Schistosoma mansoni infestation. A cross-sectional study was performed to assess factors associated with S. mansoni endemicity in a municipality in Northeast Brazil with a history of reporting schistosomiasis. Participants were divided into four groups: 1) new S. mansoni cases (n = 44), 2) past history of S. mansoni treatment (n = 78), 3) immediate neighbors (n = 158), and 4) nearby controls (n = 35). Multiple comparisons analysis was performed. Subjects had a mean of 6.6 ± 3.9 years of education, and no difference was observed regarding family income (one-way ANOVA, P = 0.215). A total of 95.9% of the individuals had rudimentary cesspit as sanitary wastewater. The mean body mass index was 28.3 ± 5.1, with 41.0% and 24.1% overweight and obesity, respectively. Of note, 28.9% of adults had hypertension. Hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin were higher in the recent S. mansoni treated group (Wilks' lambda, P < 0.001). Male gender was more prevalent in new S. mansoni cases (likelihood ratio, P < 0.001), close proximity to water collections was a risk for S. mansoni infestation (likelihood ratio, P < 0.001), and a better hematological status was observed in individuals recently treated with praziquantel. This study indicates the need to maintain surveillance for S. mansoni in low-transmission areas and the need to establish community-based interventions to control transmission.
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Affiliation(s)
- Danielle V F Bezerra
- 1Institute of Tropical Medicine of Rio Grande do Norte, Natal, Brazil.,2Postgraduate Program in Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil
| | - José W Queiroz
- 1Institute of Tropical Medicine of Rio Grande do Norte, Natal, Brazil.,3Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Victor A V Câmara
- 1Institute of Tropical Medicine of Rio Grande do Norte, Natal, Brazil
| | - Bruna L L Maciel
- 2Postgraduate Program in Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil.,4Department of Nutrition, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Eliana L T Nascimento
- 1Institute of Tropical Medicine of Rio Grande do Norte, Natal, Brazil.,5Department of Infectious Diseases, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Selma M B Jerônimo
- 1Institute of Tropical Medicine of Rio Grande do Norte, Natal, Brazil.,2Postgraduate Program in Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil.,3Department of Biochemistry, Federal University of Rio Grande do Norte, Natal, Brazil.,6Institute of Science and Technology of Tropical Diseases, INCT-DT, Salvador, Brazil
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16
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Wharton-Smith A, Rassi C, Batisso E, Ortu G, King R, Endriyas M, Counihan H, Hamade P, Getachew D. Gender-related factors affecting health seeking for neglected tropical diseases: findings from a qualitative study in Ethiopia. PLoS Negl Trop Dis 2019; 13:e0007840. [PMID: 31830026 PMCID: PMC6907747 DOI: 10.1371/journal.pntd.0007840] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/11/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Despite known gender-specific differences in terms of prevalence, transmission and exposure to neglected tropical diseases (NTDs), there is limited discussion of the influence of gender in NTD programmes and interventions. There is a paucity of research on how gender interacts with NTD service provision and uptake. This study, part of broader implementation research in Ethiopia, applied a gender lens to health seeking for five NTDs: lymphatic filariasis, podoconiosis, schistosomiasis, soil-transmitted helminth infection and trachoma. METHODOLOGY/PRINCIPAL FINDINGS The study was conducted in a district of the Southern Nations, Nationalities, and Peoples' Region of Ethiopia where the five NTDs are prevalent. A qualitative methodology was adopted to explore participants' perspectives and experiences. Data generation methods included 20 interviews and four focus group discussions. Community members, volunteer Health Development Army leaders, Health Extension Workers and a range of health workers at the health post, health centre and hospital level (n = 59) were purposively sampled. Interviews and focus group discussions were audio recorded, transcribed verbatim into English then analysed through open coding, drawing on constant comparative methods. Gender related factors affected care seeking for NTDs and were described as reasons for not seeking care, delayed care seeking and treating NTDs with natural remedies. Women faced additional challenges in seeking health care due to gender inequalities and power dynamics in their domestic partnerships. Participants recommended raising community awareness about NTDs, however this remains problematic due to gender and social norms around appropriate discourse with members of the opposite gender. CONCLUSIONS/SIGNIFICANCE The findings from this study provide crucial insights into how gender interacts with accessing health services, at different levels of the health system. If we are committed to leaving no one behind and achieving universal health coverage, it is essential to address gender disparities to access and utilisation of interventions delivered by national NTD programmes.
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Affiliation(s)
| | | | | | | | - Rebecca King
- The Nuffield Centre for International Health & Development, University of Leeds, Leeds, United Kingdom
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17
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Angora EK, Boissier J, Menan H, Rey O, Tuo K, Touré AO, Coulibaly JT, Méité A, Raso G, N'Goran EK, Utzinger J, Balmer O. Prevalence and Risk Factors for Schistosomiasis among Schoolchildren in two Settings of Côte d'Ivoire. Trop Med Infect Dis 2019; 4:tropicalmed4030110. [PMID: 31340504 PMCID: PMC6789509 DOI: 10.3390/tropicalmed4030110] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/13/2019] [Accepted: 07/15/2019] [Indexed: 01/05/2023] Open
Abstract
Schistosomiasis is a parasitic disease affecting more than 250 million people, primarily in sub-Saharan Africa. In Côte d’Ivoire both Schistosoma haematobium (causing urogenital schistosomiasis) and Schistosoma mansoni (causing intestinal schistosomiasis) co-exist. This study aimed to determine the prevalence of S. haematobium and S. mansoni and to identify risk factors among schoolchildren in the western and southern parts of Côte d’Ivoire. From January to April 2018, a cross-sectional study was carried out including 1187 schoolchildren aged 5–14 years. Urine samples were examined by a filtration method to identify and count S. haematobium eggs, while stool samples were subjected to duplicate Kato-Katz thick smears to quantify eggs of S.mansoni and soil-transmitted helminths. Data on sociodemographic, socioeconomic, and environmental factors were obtained using a pretested questionnaire. Multivariate logistic regression was employed to test for associations between variables. We found a prevalence of S. haematobium of 14.0% (166 of 1187 schoolchildren infected) and a prevalence of S. mansoni of 6.1% (66 of 1089 schoolchildren infected). In the southern part of Côte d’Ivoire, the prevalence of S. haematobium was 16.1% with a particularly high prevalence observed in Sikensi (35.6%), while S. mansoni was most prevalent in Agboville (11.2%). Swimming in open freshwater bodies was the main risk factor for S. haematobium infection (adjusted odds ratio (AOR) = 127.0, 95% confidence interval (CI): 25.0–634.0, p < 0.001). Fishing and washing clothes in open freshwater bodies were positively associated with S. haematobium and S. mansoni infection, respectively. Preventive chemotherapy using praziquantel should be combined with setting-specific information, education, and communication strategies in order to change children’s behavior, thus avoiding contact with unprotected open freshwater.
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Affiliation(s)
- Etienne K Angora
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland.
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland.
- Unité de Formation et de Recherche Sciences Pharmaceutiques et Biologiques, Université Félix Houphouët-Boigny, Abidjan BPV 34, Côte d'Ivoire.
| | - Jérôme Boissier
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan Via Domitia, 66860 Perpignan, France
| | - Hervé Menan
- Unité de Formation et de Recherche Sciences Pharmaceutiques et Biologiques, Université Félix Houphouët-Boigny, Abidjan BPV 34, Côte d'Ivoire
| | - Olivier Rey
- IHPE, Univ. Montpellier, CNRS, Ifremer, Univ. Perpignan Via Domitia, 66860 Perpignan, France
| | - Karim Tuo
- Institut Pasteur de Côte d'Ivoire, Abidjan BPV 490, Côte d'Ivoire
| | - Andre O Touré
- Institut Pasteur de Côte d'Ivoire, Abidjan BPV 490, Côte d'Ivoire
| | - Jean T Coulibaly
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d'Ivoire
| | - Aboulaye Méité
- Programme National de Lutte contre les Maladies Tropicales Négligées à Chimiothérapie Préventive, 06 BP 6394, Abidjan 06, Côte d'Ivoire
| | - Giovanna Raso
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
| | - Eliézer K N'Goran
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 BP 1303, Abidjan 01, Côte d'Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 BP 770, Abidjan 22, Côte d'Ivoire
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
| | - Oliver Balmer
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland
- University of Basel, P.O. Box, CH-4003 Basel, Switzerland
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18
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O'Connell EM, Mitchell T, Papaiakovou M, Pilotte N, Lee D, Weinberg M, Sakulrak P, Tongsukh D, Oduro-Boateng G, Harrison S, Williams SA, Stauffer WM, Nutman TB. Ancylostoma ceylanicum Hookworm in Myanmar Refugees, Thailand, 2012-2015. Emerg Infect Dis 2019; 24. [PMID: 30014834 PMCID: PMC6056130 DOI: 10.3201/eid2408.180280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
This hookworm, uncommonly found in humans, has a higher cure rate than that for Necator americanus hookworm. During 2012–2015, US-bound refugees living in Myanmar–Thailand border camps (n = 1,839) were surveyed for hookworm infection and treatment response by using quantitative PCR. Samples were collected at 3 time points: after each of 2 treatments with albendazole and after resettlement in the United States. Baseline prevalence of Necator americanus hookworm was 25.4%, Ancylostoma duodenale 0%, and Ancylostoma ceylanicum (a zoonosis) 5.4%. Compared with N. americanus prevalence, A. ceylanicum hookworm prevalence peaked in younger age groups, and blood eosinophil concentrations during A. ceylanicum infection were higher than those for N. americanus infection. Female sex was associated with a lower risk for either hookworm infection. Cure rates after 1 dose of albendazole were greater for A. ceylanicum (93.3%) than N. americanus (65.9%) hookworm (p<0.001). Lower N. americanus hookworm cure rates were unrelated to β-tubulin single-nucleotide polymorphisms at codons 200 or 167. A. ceylanicum hookworm infection might be more common in humans than previously recognized.
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19
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Odero SO, Ogonda L, Sang D, Munde EO, Shiluli C, Chweya P. Distribution of Biomphalaria Snails in Associated Vegetations and Schistosome Infection Prevalence Along the Shores of Lake Victoria in Mbita, Kenya: A Cross-Sectional Study. East Afr Health Res J 2019; 3:172-177. [PMID: 34308211 PMCID: PMC8279174 DOI: 10.24248/eahrj-d-19-00013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 09/11/2019] [Indexed: 11/20/2022] Open
Abstract
Background: Schistosomiasis due to Schistosoma mansoni remains a major public health problem and cause of morbidity and mortality in sub-Saharan Africa despite the implementation of control programmes. More than 6 million Kenyans are at risk of infection. Regarding control measures, Biomphalaria snail species, which are the obligatory intermediate hosts for transmission of S. mansoni, have been neglected. Mbita subcounty in Homa Bay County, western Kenya, along Lake Victoria basin, has a high prevalence of S. mansoni infection despite mass drug administration. This study aimed to determine the abundance of Biomphalaria, with their associated vegetation and schistosome infection rates, along Mbita shoreline. Methods: Sixteen purposively selected sites along the Mbita shoreline were sampled for Biomphalaria snails using a 30-minute scooping technique. Global positioning system technology was used to map selected sites. The associated vegetation at sampling sites were collected and identified. Schistosome infection status among the snails was determined via the detection of cercaria shedding. Results: A total of 3,135 Biomphalaria sudanica snails were collected. The number of snails collected differed significantly between the 16 sites (F=11.735; degrees of freedom [df]=15.836; P<.001). Significant mean differences (MD) were also observed in terms of the number of snails collected per vegetation type (F=7.899; df=5.846; P<.001). The mean number of snails collected from Cyprus gracilis was significantly higher than that from Enydra fluactuants (MD= 2.03; P<.001), Eichhornia crassipes (MD=4.15; P<.010), and E. fluactuants mixed with E. crassipes (MD=2.516; P<.010). A total of 21 (0.67%) snails shed human cercariae, while 27 (0.86%) snails shed nonhuman cercariae, despite 14 sites having human faeces contamination. Conclusion: Although the schistosome infection prevalence among the snails was low, these sites may still be important exposure sites. C. gracilis is the main vegetation type associated with a high abundance of Biomphalaria snails. Molecular techniques are necessary for verification of schistosome positivity among the snails.
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Affiliation(s)
- Sabiano O Odero
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - Lilian Ogonda
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - David Sang
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - Elly O Munde
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya.,School of Health Sciences, Kirinyaga University, Kerugoya, Kenya
| | - Clement Shiluli
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - Patrick Chweya
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
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20
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Bergquist R, Elmorshedy H. Artemether and Praziquantel: Origin, Mode of Action, Impact, and Suggested Application for Effective Control of Human Schistosomiasis. Trop Med Infect Dis 2018; 3:tropicalmed3040125. [PMID: 30572592 PMCID: PMC6306701 DOI: 10.3390/tropicalmed3040125] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/05/2018] [Accepted: 12/11/2018] [Indexed: 02/02/2023] Open
Abstract
The stumbling block for the continued, single-drug use of praziquantel (PZQ) against schistosomiasis is less justified by the risk of drug resistance than by the fact that this drug is inactive against juvenile parasites, which will mature and start egg production after chemotherapy. Artemisinin derivatives, currently used against malaria in the form of artemisinin-based combination therapy (ACT), provide an opportunity as these drugs are not only active against malaria plasmodia, but surprisingly also against juvenile schistosomes. An artemisinin/PZQ combination would be complementary, and potentially additive, as it would kill two schistosome life cycle stages and thus confer a transmission-blocking modality to current chemotherapy. We focus here on single versus combined regimens in endemic settings. Although the risk of artemisinin resistance, already emerging with respect to malaria therapy in Southeast Asia, prevents use in countries where ACT is needed for malaria care, an artemisinin-enforced praziquantel treatment (APT) should be acceptable in regions of North Africa (including Egypt), the Middle East, China, and Brazil that are not endemic for malaria. Thanks to recent progress with respect to high-resolution diagnostics, based on circulating schistosome antigens in humans and molecular approaches for snail surveys, it should be possible to keep areas scheduled for schistosomiasis elimination under surveillance, bringing rapid response to bear on problems arising. The next steps would be to investigate where and for how long APT should be applied to make a lasting impact. A large-scale field trial in an area with modest transmission should tell how apt this approach is.
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Affiliation(s)
| | - Hala Elmorshedy
- College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.
- Department of Tropical Health, High Institute of Public Health, Alexandria University, Alexandria 21561, Egypt.
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21
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Hermann E, Gaayeb L, Sow PS, Seck M, Sagna AB, Senghor S, Bandagny L, Brinkhuizen C, Delcroix-Genete D, Schacht AM, Riveau G. Sex-dependent interactions between leptin, wasting and humoral immunity in two ethnic communities of school-aged children differentially exposed to Schistosoma haematobium. Trans R Soc Trop Med Hyg 2017; 111:448-456. [PMID: 29351649 DOI: 10.1093/trstmh/trx078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 12/12/2017] [Indexed: 01/09/2023] Open
Abstract
Background Leptin is a nutritional hormone whose production is generally higher in females. We investigated how leptin is associated with sex dimorphism during urinary schistosomiasis in relation with wasting. Methods A cross-sectional study was carried out in three villages in northern Senegal. Ninety-eight school-aged children belonging to the Fulani or Wolof villages were enrolled. We performed parasitic diagnosis and anthropometric measurement to evaluate nutritional status. We collected peripheral blood to determine the amount of circulating leptin and immunoglobulin G (IgG), IgG4 and IgE directed to soluble worm antigen preparation (SWAP). Results The prevalence of Schistosoma haematobium infection was higher among boys regardless of ethnic group, but exposure to parasites did not exacerbate malnutrition. The greater ability of girls to produce leptin was not altered by schistosomiasis and was recovered in both ethnic groups. However, while the usual correlation between leptin and fat storage was preserved in Fulani girls, it was disrupted in Fulani boys, who displayed a remarkable susceptibility for wasting. Finally, we observed that leptin was negatively associated with the level of antibodies in Wolof boys. Conclusions Leptin can be disconnected from body fat and may exert a sex-dependent influence on host immune response to S. haematobium infection in Senegalese children.
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Affiliation(s)
- Emmanuel Hermann
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France.,Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Lobna Gaayeb
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France.,Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Papa S Sow
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Modou Seck
- Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Andre B Sagna
- Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Simon Senghor
- Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Lydie Bandagny
- Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
| | - Clement Brinkhuizen
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Delphine Delcroix-Genete
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Anne-Marie Schacht
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Gilles Riveau
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 8204 - CIIL - Center for Infection and Immunity of Lille, F-59000 Lille, France.,Centre de Recherche Biomédicale Espoir pour la Sante, BP 226, Saint-Louis, Senegal
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22
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Chadeka EA, Nagi S, Sunahara T, Cheruiyot NB, Bahati F, Ozeki Y, Inoue M, Osada-Oka M, Okabe M, Hirayama Y, Changoma M, Adachi K, Mwende F, Kikuchi M, Nakamura R, Kalenda YDJ, Kaneko S, Hirayama K, Shimada M, Ichinose Y, Njenga SM, Matsumoto S, Hamano S. Spatial distribution and risk factors of Schistosoma haematobium and hookworm infections among schoolchildren in Kwale, Kenya. PLoS Negl Trop Dis 2017; 11:e0005872. [PMID: 28863133 PMCID: PMC5599053 DOI: 10.1371/journal.pntd.0005872] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 09/14/2017] [Accepted: 08/14/2017] [Indexed: 11/19/2022] Open
Abstract
Background Large-scale schistosomiasis control programs are implemented in regions with diverse social and economic environments. A key epidemiological feature of schistosomiasis is its small-scale heterogeneity. Locally profiling disease dynamics including risk factors associated with its transmission is essential for designing appropriate control programs. To determine spatial distribution of schistosomiasis and its drivers, we examined schoolchildren in Kwale, Kenya. Methodology/Principal findings We conducted a cross-sectional study of 368 schoolchildren from six primary schools. Soil-transmitted helminths and Schistosoma mansoni eggs in stool were evaluated by the Kato-Katz method. We measured the intensity of Schistosoma haematobium infection by urine filtration. The geometrical mean intensity of S. haematobium was 3.1 eggs/10 ml urine (school range, 1.4–9.2). The hookworm geometric mean intensity was 3.2 eggs/g feces (school range, 0–17.4). Heterogeneity in the intensity of S. haematobium and hookworm infections was evident in the study area. To identify factors associated with the intensity of helminth infections, we utilized negative binomial generalized linear mixed models. The intensity of S. haematobium infection was associated with religion and socioeconomic status (SES), while that of hookworm infection was related to SES, sex, distance to river and history of anthelmintic treatment. Conclusions/Significance Both S. haematobium and hookworm infections showed micro-geographical heterogeneities in this Kwale community. To confirm and explain our observation of high S. haematobium risk among Muslims, further extensive investigations are necessary. The observed small scale clustering of the S. haematobium and hookworm infections might imply less uniform strategies even at finer scale for efficient utilization of limited resources. The World Health Organization is spearheading the war on neglected tropical diseases, including helminth infections, by encouraging its member states to intensify control efforts. This call has recently been answered in most endemic regions of helminthiasis and governments are scaling up chemotherapy-based control programs in collaboration with private and public partners. However, it is necessary to clearly understand factors driving local transmission dynamics of helminth infections to design effective control programs. Here, we conducted a cross-sectional survey of 368 primary schoolchildren in Kwale, Kenya, and identified factors associated with the intensity of Schistosoma haematobium and hookworm infections. The negative binomial generalized linear mixed model showed the intensity of S. haematobium infection was much higher among Muslims and schoolchildren from low socioeconomic status households. High intensity of hookworm infection was associated with sex, SES, distance to river and history of anthelmintic treatment. Our findings demonstrate considering social and cultural drivers of NTDs could be beneficial in designing of efficient control programs and expediting NTDs control.
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Affiliation(s)
- Evans Asena Chadeka
- Leading Program, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Sachiyo Nagi
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Toshihiko Sunahara
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Vector Ecology and Environment, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | | | - Felix Bahati
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Yuriko Ozeki
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Manabu Inoue
- Department of Bacteriology and Virology, Osaka-City University Graduate School of Medicine, Osaka, Japan
| | - Mayuko Osada-Oka
- Food Hygiene and Environmental Health Division of Applied Life Science, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Mayuko Okabe
- Department of Immunology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yukio Hirayama
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Mwatasa Changoma
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Keishi Adachi
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Immunology, Yamaguchi University Graduate School of Medicine, Ube, Japan
| | - Faith Mwende
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Mihoko Kikuchi
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Risa Nakamura
- Leading Program, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Yombo Dan Justin Kalenda
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Eco-Epidemiology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Satoshi Kaneko
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
- Department of Eco-Epidemiology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Kenji Hirayama
- Leading Program, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Department of Immunogenetics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Masaaki Shimada
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
- Department of Eco-Epidemiology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Yoshio Ichinose
- Leading Program, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
| | - Sammy M. Njenga
- Eastern and Southern Africa Centre of International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Sohkichi Matsumoto
- Department of Bacteriology, Niigata University School of Medicine, Niigata, Japan
| | - Shinjiro Hamano
- Leading Program, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
- Department of Parasitology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- The Joint Usage/Research Center on Tropical Disease, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
- Nagasaki University, Kenya Research Station, NUITM-KEMRI Project, Nairobi, Kenya
- * E-mail:
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Gbalégba NGC, Silué KD, Ba O, Ba H, Tian-Bi NTY, Yapi GY, Kaba A, Koné B, Utzinger J, Koudou BG. Prevalence and seasonal transmission of Schistosoma haematobium infection among school-aged children in Kaedi town, southern Mauritania. Parasit Vectors 2017; 10:353. [PMID: 28747222 PMCID: PMC5530530 DOI: 10.1186/s13071-017-2284-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 07/11/2017] [Indexed: 12/25/2022] Open
Abstract
Background Mauritania is at the fringe of transmission of human schistosomiasis, which mainly occurs in the southern and southeastern parts of the country. This study aimed to assess the influence of rainfall seasonality on the prevalence of Schistosoma haematobium infection among school-aged children in Kaedi, southern Mauritania. Methods Cross-sectional surveys (i.e. parasitological, malacological and observations on water-related human activities) were carried out in Kaedi between September 2014 and May 2015, during both the wet and dry seasons. A total of 2162 children aged 5–15 years provided a single urine sample that was subjected to S. haematobium diagnosis. Snails were sampled and checked for cercarial shedding. Water contact patterns of the local population were recorded by direct observation. Results The prevalence of S. haematobium was 4.0% (86/2162, 95% confidence interval (CI): 3.2–4.9%) with a geometric mean egg count per 10 ml of urine of 3.7 (95% CI: 2.8–4.3). Being male (adjusted odds ratio (aOR) 1.78, 95% CI: 1.13–2.80), being at primary school (aOR 1.73, 95% CI: 1.04–2.87) and dry season (aOR 0.56, 95% CI: 0.35–0.89) were significantly associated with S. haematobium. Among 284 potential intermediate host snail specimens collected over the rainy and dry seasons, three species were identified: Bulinus senegalensis (n = 13) and B. forskalii (n = 161) in the rainy season, and B. truncatus (n = 157) in the wet season. No snail was shedding cercariae. On average, seven human water contacts were recorded per hour per observer over a 28-day observation period. Twelve types of water contact activities were identified among which, swimming/bathing was predominant (n = 3788, 36.9%), followed by washing clothes (n = 2016, 19.7%) and washing dishes (n = 1322, 12.9%). Females (n = 5270, 51.4%) were slightly more in contact with water than males (n = 4983, 48.6%). The average time spent in the water per person per day was 14.2 min (95% CI: 13.8–14.6 min). The frequency and duration of water contact followed a seasonal pattern. Conclusion Our findings demonstrate a low prevalence and intensity of S. haematobium among school-aged children in Kaedi. Appropriate integrated control measures, including health education among at-risk communities and snail control may help to interrupt transmission of S. haematobium in Kaedi.
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Affiliation(s)
- N'Guessan G C Gbalégba
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, 02 B.P. 801, Abidjan 02, Côte d'Ivoire. .,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.
| | - Kigbafori D Silué
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 B.P. 582, Abidjan 22, Côte d'Ivoire
| | - Ousmane Ba
- Laboratoire de Parasitologie - Mycologie, Institut National de Recherches en Santé Publique, B.P, 695, Nouakchott, Mauritania
| | - Hampâté Ba
- Laboratoire de Parasitologie - Mycologie, Institut National de Recherches en Santé Publique, B.P, 695, Nouakchott, Mauritania
| | - Nathan T Y Tian-Bi
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 B.P. 582, Abidjan 22, Côte d'Ivoire
| | - Grégoire Y Yapi
- Centre d'Entomologie Médicale et Vétérinaire (CEMV), Université Alassane Ouattara, Bouaké, Côte d'Ivoire
| | - Aboudramane Kaba
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.,Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, 22 B.P. 582, Abidjan 22, Côte d'Ivoire
| | - Brama Koné
- Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.,Université Péléforo Gon Coulibaly, B.P, 1328,, Korhogo, Côte d'Ivoire
| | - Jürg Utzinger
- Swiss Tropical and Public Health Institute, P.O. Box, CH-4002, Basel, Switzerland.,University of Basel, P.O. Box, CH-4003, Basel, Switzerland
| | - Benjamin G Koudou
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, 02 B.P. 801, Abidjan 02, Côte d'Ivoire.,Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, 01 B.P. 1303, Abidjan 01, Côte d'Ivoire.,Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Dawaki S, Al-Mekhlafi HM, Ithoi I, Ibrahim J, Abdulsalam AM, Ahmed A, Sady H, Atroosh WM, Al-Areeqi MA, Elyana FN, Nasr NA, Surin J. PREVALENCE AND RISK FACTORS OF SCHISTOSOMIASIS AMONG HAUSA COMMUNITIES IN KANO STATE, NIGERIA. Rev Inst Med Trop Sao Paulo 2017; 58:54. [PMID: 27410914 PMCID: PMC4964323 DOI: 10.1590/s1678-9946201658054] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 03/07/2016] [Indexed: 12/17/2022] Open
Abstract
Schistosomiasis remains one of the most prevalent neglected tropical diseases especially in Nigeria which has the greatest number of infected people worldwide. A cross-sectional study was conducted among 551 participants from Kano State, North Central Nigeria. Fecal samples were examined for the presence of Schistosoma mansoni eggs using the formalin-ether sedimentation method while the urine samples were examined using the filtration technique for the presence of S. haematobium eggs. Demographic, socioeconomic and environmental information was collected using a pre-validated questionnaire. The overall prevalence of schistosomiasis was 17.8%, with 8.9% and 8.3% infected with S. mansoni and S. haematobium, respectively and 0.5% presenting co-infection with both species. The multiple logistic regression analysis revealed that age < 18 years (OR = 2.13; 95% CI; 1.34- 3.41), presence of infected family members (OR = 3.98; 95% CI; 2.13-7.46), and history of infection (OR = 2.87; 95% CI; 1.87- 4.56) were the significant risk factors associated with schistosomiasis in these communities. In conclusion, this study revealed that schistosomiasis is still prevalent among Hausa communities in Nigeria. Mass drug administration, health education and community mobilization are imperative strategies to significantly reduce the prevalence and morbidity of schistosomiasis in these communities.
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Affiliation(s)
- Salwa Dawaki
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Hesham Mahyoub Al-Mekhlafi
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ; .,Endemic and Tropical Diseases Unit, Medical Research Center, Jazan University, Jazan, Saudi Arabia. E-mail:
| | - Init Ithoi
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Jamaiah Ibrahim
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Awatif Mohammed Abdulsalam
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Abdulhamid Ahmed
- Department of Biology, Faculty of Natural and Applied Sciences, Umaru Musa Yar'adua University. Katsina, Katsina State, Nigeria. E-mail:
| | - Hany Sady
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Wahib Mohammed Atroosh
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Mona Abdullah Al-Areeqi
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Fatin Nur Elyana
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Nabil Ahmed Nasr
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
| | - Johari Surin
- Department of Parasitology, Faculty of Medicine, University of Malaya. 50603 Kuala Lumpur, Malaysia. E-mails: ; ; ; ; ; ; ; ; ; ;
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25
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Simoonga C, Kazembe LN. Using the hierarchical ordinal regression model to analyse the intensity of urinary schistosomiasis infection in school children in Lusaka Province, Zambia. Infect Dis Poverty 2017; 6:43. [PMID: 28219411 PMCID: PMC5319044 DOI: 10.1186/s40249-017-0262-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/16/2017] [Indexed: 12/19/2022] Open
Abstract
Background Urinary schistosomiasis has been a major public health problem in Zambia for many years. However, the disease profile may vary in different locale due to the changing ecosystem that contributes to the risk of acquiring the disease. The objective of this study was to quantify risk factors associated with the intensity of urinary schistosomiasis infection in school children in Lusaka Province, Zambia, in order to better understand local transmission. Methods Data were obtained from 1 912 school children, in 20 communities, in the districts of Luangwa and Kafue in Lusaka Province. Both individual- and community-level covariates were incorporated into an ordinal logistic regression model to predict the probability of an infection being a certain intensity in a three-category outcome response: 0 = no infection, 1 = light infection, and 2 = moderate/heavy infection. Random effects were introduced to capture unobserved heterogeneity. Results Overall, the risk of urinary schistosomiasis was strongly associated with age, altitude at which the child lived, and sex. Weak associations were observed with the normalized difference vegetation index, maximum temperature, and snail abundance. Detailed analysis indicated that the association between infection intensities and age and altitude were category-specific. Particularly, infection intensity was lower in children aged between 5 and 9 years compared to those aged 10 to 15 years (OR = 0.72, 95% CI = 0.51–0.99). However, the age-specific risk changed at different levels of infection, such that when comparing children with light infection to those who were not infected, age was associated with a lower odds (category 1 vs category 0: OR = 0.71, 95% CI: 0.50–0.99), yet such a relation was not significant when considering children who were moderately or heavily infected compared to those with a light or no infection (category 2 vs category 0: OR = 0.96, 95% CI: 0.45–1.64). Overall, we observed that children living in the valley were less likely to acquire urinary schistosomiasis compared to those living in plateau areas (OR = 0.48, 95% CI: 0.16–0.71). However, category-specific effects showed no significant association in category 1 (light infection), whereas in category 2 (moderate/high infection), the risk was still significantly lower for those living in the valley compared to those living in plateau areas (OR = 0.18, 95% CI: 0.04–0.75). Conclusions This study demonstrates the importance of understanding the dynamics and heterogeneity of infection in control efforts, and further suggests that apart from the well-researched factors of Schistosoma intensity, various other factors influence transmission. Control programmes need to take into consideration the varying infection intensities of the disease so that effective interventions can be designed. Electronic supplementary material The online version of this article (doi:10.1186/s40249-017-0262-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Christopher Simoonga
- Ministry of Health, Ndeke House, Haile Selassie Avenue, P.O. Box 30205, Lusaka, Zambia
| | - Lawrence N Kazembe
- Mathematical Sciences Department, Chancellor College, University of Malawi, P.O. Box 280, Zomba, Malawi. .,Statistics and Population Studies Department, University of Namibia, Private Bag 13301, Windhoek, Namibia.
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26
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Cabello RKS, Beck LC, Massara CL, Murta FL, Guimarães RJ, Pieri OS, Schall VT, Favre TC. Schistosoma mansoni infection and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to educational actions. Acta Trop 2016; 164:208-215. [PMID: 27647573 DOI: 10.1016/j.actatropica.2016.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/13/2016] [Accepted: 09/15/2016] [Indexed: 11/25/2022]
Abstract
As a signatory to World Health Assembly Resolution WHA65.21 on eliminating schistosomiasis, the Brazilian Ministry of Health (MoH) recommends early identification and timely treatment of the infection carriers for morbidity control, plus complementary preventive measures, such as health education, for transmission control. This study reports infection and awareness of schistosomiasis among schoolchildren before the implementation of school-based educational actions in an endemic municipality with persisting moderate prevalence levels despite successive control campaigns since the late 1990s. A questionnaire was applied in April 2013 to schoolchildren in the middle years of schooling (6th to 8th year) of Malacacheta municipality to assess baseline knowledge and risk behaviour related to schistosomiasis. A stool survey was conducted in May/June 2013 in 2519 schoolchildren from all years of fundamental education (first to 9th year) to identify the infection carriers, as well as to assess baseline prevalence and intensity of infection using the Kato-Katz method (one sample, two slides). The infected schoolchildren were treated promptly with single-dose praziquantel 60mg/kg and followed up after 45days for treatment efficacy. Relevant outcomes from baseline stool survey, treatment and follow-up were statistically evaluated in relation to area of residence (rural/urban), gender, age group (<11/≥years) and infection. Adherence to baseline survey was 81.2%, and prevalence of infection was 21.4%. Of the 539 positives, 60 (11.1%) had ≥400 eggs per gram of faeces (heavy-intensity infection). Prevalence of infection was significantly higher among rural residents and≥11year olds, whereas intensity of infection was higher among rural residents,≥11year olds and boys. Adherence by the positives to treatment was 93.3% and adherence by the treated children to 45-day follow-up was 72.2%. At 45days after treatment, 97.0% of the 363 children surveyed were egg-negative; the egg reduction rate was 99.4%. Of the 924 children who responded to the questionnaire, 95.5% showed awareness of schistosomiasis, although 76.2% reported contact with natural, unsafe bodies of water. Reported contact with water was significantly more frequent among infected than non-infected, and boys than girls. The results show persisting infection and risk behaviour among schoolchildren, regardless of their basic knowledge about schistosomiasis. These are grounds for implementing specific educational actions to improve awareness and behavioural change, jointly with other control measures, to attain the MoH goals.
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Monde C, Syampungani S, van den Brink PJ. Natural and human induced factors influencing the abundance of Schistosoma host snails in Zambia. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:370. [PMID: 27230422 PMCID: PMC4882361 DOI: 10.1007/s10661-016-5351-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 05/05/2016] [Indexed: 06/05/2023]
Abstract
Schistosomiasis remains a global public health problem affecting about 240 million people. In Zambia, 2 million are infected while 3 million live with the risk of getting infected. Research and interventions relating to schistosomiasis are mainly linked to disease epidemiology. Malacological and ecological aspects of the disease are superficially understood. Developing effective control measures requires an understanding of interacting environmental and socioeconomic factors of host snails vis-a-vis schistosomiasis. Therefore, the present work involved collecting social and environmental data in a large field study in two zones in Zambia that are different in terms of temperature and rainfall amounts. Social data collected through questionnaires included demographic, educational and knowledge of schistosomiasis disease dynamics. Environmental data included physicochemical factors, aquatic plants and snails. Gender (P < 0.001) significantly influences livelihood strategies, while age (P = 0.069) and level of education (P = 0.086) have a moderate influence in zone I. In zone III, none of these factors (age, P = 0.378; gender, P = 0.311; education, P = 0.553) play a significant role. Environmental parameters explained 43 and 41 % variation in species composition for zones I and III, respectively. Most respondents' (52 %, 87 %) perception is that there are more cases of bilharzia in hot season than in other seasons (rainy season 23 %, 7 %; cold season 8 %, 0 % and year round 17 %, 6 %) for zone I and zone III, respectively.
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Affiliation(s)
- Concillia Monde
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
- Department of Zoology and Aquatic Sciences, Copperbelt University, P.O. Box 21692, Jambo Drive, Riverside, Kitwe, Zambia.
| | - Stephen Syampungani
- Department of Plant and Environmental Sciences, Copperbelt University, P.O Box 21692, Jambo Drive, Riverside, Kitwe, Zambia
| | - Paul J van den Brink
- Department of Aquatic Ecology and Water Quality Management, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
- Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands
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Grimes JET, Croll D, Harrison WE, Utzinger J, Freeman MC, Templeton MR. The roles of water, sanitation and hygiene in reducing schistosomiasis: a review. Parasit Vectors 2015; 8:156. [PMID: 25884172 PMCID: PMC4377019 DOI: 10.1186/s13071-015-0766-9] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/18/2015] [Indexed: 11/10/2022] Open
Abstract
Schistosomiasis is a disease caused by infection with blood flukes of the genus Schistosoma. Transmission of, and exposure to, the parasite result from faecal or urinary contamination of freshwater containing intermediate host snails, and dermal contact with the same water. The World Health Assembly resolution 65.21 from May 2012 urges member states to eliminate schistosomiasis through preventive chemotherapy (i.e. periodic large-scale administration of the antischistosomal drug praziquantel to school-aged children and other high-risk groups), provision of water, sanitation and hygiene (WASH) and snail control. However, control measures focus almost exclusively on preventive chemotherapy, while only few studies made an attempt to determine the impact of upgraded access to safe water, adequate sanitation and good hygiene on schistosome transmission. We recently completed a systematic review and meta-analysis pertaining to WASH and schistosomiasis and found that people with safe water and adequate sanitation have significantly lower odds of a Schistosoma infection. Importantly though, the transmission of schistosomiasis is deeply entrenched in social-ecological systems, and hence is governed by setting-specific cultural and environmental factors that determine human behaviour and snail populations. Here, we provide a comprehensive review of the literature, which explores the transmission routes of schistosomes, particularly focussing on how these might be disrupted with WASH-related technologies and human behaviour. Additionally, future research directions in this area are highlighted.
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Affiliation(s)
- Jack E T Grimes
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK.
| | - David Croll
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, , CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, , CH-4003, Basel, Switzerland.
| | - Wendy E Harrison
- Schistosomiasis Control Initiative, Imperial College London, London, SW7 2AZ, UK.
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, , CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, , CH-4003, Basel, Switzerland.
| | - Matthew C Freeman
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA.
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK.
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Van den Broeck F, Meurs L, Raeymaekers JAM, Boon N, Dieye TN, Volckaert FAM, Polman K, Huyse T. Inbreeding within human Schistosoma mansoni: do host-specific factors shape the genetic composition of parasite populations? Heredity (Edinb) 2014; 113:32-41. [PMID: 24619176 DOI: 10.1038/hdy.2014.13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 01/09/2014] [Accepted: 01/17/2014] [Indexed: 11/09/2022] Open
Abstract
The size, structure and distribution of host populations are key determinants of the genetic composition of parasite populations. Despite the evolutionary and epidemiological merits, there has been little consideration of how host heterogeneities affect the evolutionary trajectories of parasite populations. We assessed the genetic composition of natural populations of the parasite Schistosoma mansoni in northern Senegal. A total of 1346 parasites were collected from 14 snail and 57 human hosts within three villages and individually genotyped using nine microsatellite markers. Human host demographic parameters (age, gender and village of residence) and co-infection with Schistosoma haematobium were documented, and S. mansoni infection intensities were quantified. F-statistics and clustering analyses revealed a random distribution (panmixia) of parasite genetic variation among villages and hosts, confirming the concept of human hosts as 'genetic mixing bowls' for schistosomes. Host gender and village of residence did not show any association with parasite genetics. Host age, however, was significantly correlated with parasite inbreeding and heterozygosity, with children being more infected by related parasites than adults. The patterns may be explained by (1) genotype-dependent 'concomitant immunity' that leads to selective recruitment of genetically unrelated worms with host age, and/or (2) the 'genetic mixing bowl' hypothesis, where older hosts have been exposed to a wider variety of parasite strains than children. The present study suggests that host-specific factors may shape the genetic composition of schistosome populations, revealing important insights into host-parasite interactions within a natural system.
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Affiliation(s)
- F Van den Broeck
- 1] Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium [2] Unit of Medical Helminthology, Institute of Tropical Medicine, Antwerp, Belgium
| | - L Meurs
- Unit of Medical Helminthology, Institute of Tropical Medicine, Antwerp, Belgium
| | | | - N Boon
- 1] Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium [2] Unit of Medical Helminthology, Institute of Tropical Medicine, Antwerp, Belgium
| | - T N Dieye
- Laboratory of Bacteriology and Virology, Aristide Le Dantec University Hospital, Dakar, Senegal
| | - F A M Volckaert
- Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium
| | - K Polman
- Unit of Medical Helminthology, Institute of Tropical Medicine, Antwerp, Belgium
| | - T Huyse
- 1] Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven, Leuven, Belgium [2] Unit of Medical Helminthology, Institute of Tropical Medicine, Antwerp, Belgium [3] Section Invertebrates, Royal Museum for Central Africa, Tervuren, Belgium
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30
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Matoso LF, Oliveira-Prado R, Abreu MNS, Fujiwara RT, Loverde PT, Kloos H, Gazzinelli A, Correa-Oliveira R. Longitudinal analysis of antigen specific response in individuals with Schistosoma mansoni infection in an endemic area of Minas Gerais, Brazil. Trans R Soc Trop Med Hyg 2013; 107:797-805. [PMID: 24189480 PMCID: PMC3888303 DOI: 10.1093/trstmh/trt091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background Immunoepidemiologic studies have shown a relationship between IgE and IgG4 antibodies with age and with resistance and susceptibility to infection. It is believed that the IgE and IgG4 responses to soluble egg antigen (SEA) can be used for serological analysis of infection and post-treatment status. This study aimed to evaluate the association between Schistosoma mansoni infection and anti-SEA IgG4 and IgE reactivities, and determine whether these reactivities could be used as biomarkers of infection. Methods Between 2001 and 2009, a longitudinal study was performed in which parasitologic and blood specimens and socioeconomic and water-contact information were collected from 127 individuals. All patients positive for S. mansoni infection were treated. Results Schistosomiasis prevalence and the geometric mean of the egg count in 2001 were 59% and 61.05, respectively, decreasing to 26.8% and 8.78 in 2009. IgG4 anti-SEA reactivity in infected individuals was significantly higher than that in uninfected individuals at all time points. Analysis of receiver-operating characteristic (ROC) area showed that the IgG4 anti-SEA antibodies were able to predict infection by S. mansoni at each time point. Conclusion IgG4 anti-SEA reactivity can be used as a biomarker for immune monitoring of the presence of infection with S. mansoni in endemic areas.
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Affiliation(s)
- Leonardo Ferreira Matoso
- Escola de Enfermagem, Universidade Federal de Minas Gerais, Avenida Alfredo Balena 190, sala 418, 30130-100, Belo Horizonte, MG, Brazil
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31
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Meurs L, Mbow M, Vereecken K, Menten J, Mboup S, Polman K. Epidemiology of mixed Schistosoma mansoni and Schistosoma haematobium infections in northern Senegal. Int J Parasitol 2012; 42:305-11. [PMID: 22366733 DOI: 10.1016/j.ijpara.2012.02.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/03/2012] [Accepted: 02/06/2012] [Indexed: 11/28/2022]
Abstract
Due to the large overlap of Schistosoma mansoni- and Schistosoma haematobium-endemic regions in Africa, many people are at risk of co-infection, with potential adverse effects on schistosomiasis morbidity and control. Nonetheless, studies on the distribution and determinants of mixed Schistosoma infections have to date been rare. We conducted a cross-sectional survey in two communities in northern Senegal (n=857) to obtain further insight into the epidemiology of mixed infections and ectopic egg elimination. Overall prevalences of S. mansoni and S. haematobium infection were 61% and 50%, respectively, in these communities. Among infected subjects, 53% had mixed infections and 8% demonstrated ectopic egg elimination. Risk factors for mixed infection - i.e. gender, community of residence and age - were not different from what is generally seen in Schistosoma-endemic areas. Similar to overall S. mansoni and S. haematobium infections, age-related patterns of mixed infections showed the characteristic convex-shaped curve for schistosomiasis, with a rapid increase in children, a peak in adolescents and a decline in adults. Looking at the data in more detail however, the decline in overall S. haematobium infection prevalences and intensities appeared to be steeper than for S. mansoni, resulting in a decrease in mixed infections and a relative increase in single S. mansoni infections with age. Moreover, individuals with mixed infections had higher infection intensities of both S. mansoni and S. haematobium than those with single infections, especially those with ectopic egg elimination (P<0.05). High infection intensities in mixed infections, as well as age-related differences in infection patterns between S. mansoni and S. haematobium, may influence disease epidemiology and control considerably, and merit further studies into the underlying mechanisms of Schistosoma infections in co-endemic areas.
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Affiliation(s)
- Lynn Meurs
- Institute of Tropical Medicine, Antwerp, Belgium.
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