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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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Urogenital schistosomiasis and hybridization between Schistosoma haematobium and Schistosoma bovis in adults living in Richard-Toll, Senegal. Parasitology 2018; 145:1723-1726. [PMID: 30185248 DOI: 10.1017/s0031182018001415] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Since the construction of the Diama Dam (1985), the epidemiology of schistosomiasis along the Senegal River Basin (SRB) has been extremely dynamic with outbreaks of both intestinal and urogenital schistosomiasis. In the early 2000s, technicians reported cases of suspected urogenital schistosomiasis in adults from the local hospital in Richard-Toll, Lower SRB. The genetic analysis of schistosome miracidia isolated from 11 patients in 2012 from two neighbourhoods (Campement and Gaya) of Richard-Toll confirmed infection with Schistosoma haematobium but also S. haematobium/S. bovis hybrids. Thirty-seven per cent of the miracidia were S. bovis/S. haematobium hybrids and 63% were pure S. haematobium. The data are discussed in relation to the ongoing dynamic epidemiology of the schistosomes in Senegal and the need to treat non-target individuals.
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Delegue P, Picquet M, Shaw DJ, Vercruysse J, Sambou B, Ly A. Morbidity induced bySchistosoma haematobiuminfections, as assessed by ultrasound before and after treatment with praziquantel, in a recently expanded focus (Senegal River basin). ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2016. [DOI: 10.1080/00034983.1998.11813339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Abstract
SUMMARYSchistosomiasis, commonly known as bilharzia, is a parasitic disease prevalent in Africa, Asia and South America. The majority of the cases occur in Sub-Saharan Africa where schistosomiasis is a major public health problem impacting on child health and development as well as adult health when infections become chronic. Control of schistosomiasis is by treatment of infected people with the antihelminthic drug praziquantel. Current schistosome control programmes advocated by the World Health Assembly in 2001 are aimed at regular school-based integrated deworming strategies in order to reduce development of severe morbidity, promote school health and to improve cognitive potential of children. Several countries in Africa have now embarked on national scale deworming programmes treating millions of children exposed to schistosomiasis in endemic areas without prior diagnosis of infection through mass drug administration programmes. Implementing such control programmes requires a concerted effort between scientists, policy makers, health practitioners and several other stake holders and of course a receptive community. This paper considers the contributions to global schistosome control efforts made by research conducted in Zimbabwe and the historical context and developments leading to the national schistosomiasis control programme in Zimbabwe giving an example of Getting Research into Policy and Practice.
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Abstract
Mass drug administration with praziquantel is the mainstay of programs for the control of schistosomiasis morbidity. However, there is a growing recognition that treatment alone will not be sufficient for eventually effecting elimination and that additional measures will be required to interrupt transmission. In the absence of a safe and an effective vaccine for human schistosomiasis, the strategies to reduce infection levels will necessarily involve some interventions that affect the water-related stages of the schistosome life cycle: by reducing exposure to infectious water, by moderating availability of the intermediate snail host, or by decreasing contamination of water with egg-containing excreta. While much research on the importance of water on schistosomiasis has been performed, advances in these areas have perhaps languished with the ready availability of a cost-effective treatment. As some endemic areas near a shift to an elimination goal, a better understanding of water-based interventions that can be used alone or in concert with treatment will be needed. Reinvigoration of laboratory, field, and human behavioral aspects of this research now will ensure that the appropriate strategies are available by the time their implementation becomes necessary.
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Mazigo HD, Dunne DW, Kinung'hi SM, Nuwaha F. Praziquantel efficacy against Schistosoma mansoni among HIV-1 infected and uninfected adults living in fishing villages along Lake Victoria, Northwest Tanzania. Infect Dis Poverty 2014; 3:47. [PMID: 25671125 PMCID: PMC4322465 DOI: 10.1186/2049-9957-3-47] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/09/2014] [Indexed: 11/23/2022] Open
Abstract
Background Animal studies have demonstrated that functional immune responses, as determined by the levels of CD4+ cell counts and anti-schistosome antibodies responses, determine the efficacy of praziquantel. Based on this evidence, it has been hypothesised that the immunodeficiency effects of the human immunodeficiency virus (HIV)-1 infection may affect the efficacy of praziquantel in co-infected human hosts. Thus, the present study assessed the efficacy of praziquantel by comparing parasitological cure rates and the reduction in infection intensity in HIV-1 seronegative individuals infected with S. mansoni and HIV-1 seropositive individuals co-infected with S. mansoni, following treatment with a single oral dose of praziquantel. Methods This was a prospective longitudinal study which included, at baseline, 555 S. mansoni infected adults aged 21–55 years, who were either co-infected or not with HIV-1 and who lived in fishing villages along Lake Victoria in Northwest Tanzania. These individuals were treated with a single oral dose of praziquantel (40 mg/kg) and, at 12 weeks, single stool samples were obtained and examined for S. mansoni eggs using the Kato-Katz technique. Finger prick and venous blood samples were collected for HIV-1 screening and CD4+ cell quantification. Results The parasitological cure rate did not differ significantly from the HIV-1 serostatus (P = 0.12): among the co-infected individuals, the cure rate was 48.3% (14/29), and among the individuals infected only with S. mansoni, the cure rate was 62.6% (329/526). The egg reduction rate did not vary with the HIV-1 serostatus (P = 0.22): 77.22% for HIV-1 seronegative and 75% for HIV-1 seropositive individuals. The level of CD4+ cell counts (median 228 cells/μL: range 202–380 cells) did not influence the cure rate (P = 0.23) or the reduction in the intensity of the infection (P = 0.37). Conclusion The HIV-1 infection per se or its moderate immunodeficiency effects, demonstrated by the range of CD4+ cell counts observed in co-infected individuals, did not affect praziquantel efficacy, as measured by the parasitological cure rate and the reduction in intensity of infection in the present study cohort. Electronic supplementary material The online version of this article (doi:10.1186/2049-9957-3-47) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Humphrey D Mazigo
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania ; Department of Disease Control and Environmental Health, School of Public Health, College of Health Sciences, Makerere University, P.O. Box 7072, Kampala, Uganda ; Department of Pathology, Division of Microbiology and Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1QP UK
| | - David W Dunne
- Department of Pathology, Division of Microbiology and Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1QP UK
| | - Safari M Kinung'hi
- National Institute for Medical Research, Mwanza Research Centre, P.O. Box 1462, Mwanza, Tanzania
| | - Fred Nuwaha
- Department of Disease Control and Environmental Health, School of Public Health, College of Health Sciences, Makerere University, P.O. Box 7072, Kampala, Uganda
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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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Tukahebwa EM, Magnussen P, Madsen H, Kabatereine NB, Nuwaha F, Wilson S, Vennervald BJ. A very high infection intensity of Schistosoma mansoni in a Ugandan Lake Victoria Fishing Community is required for association with highly prevalent organ related morbidity. PLoS Negl Trop Dis 2013; 7:e2268. [PMID: 23936559 PMCID: PMC3723538 DOI: 10.1371/journal.pntd.0002268] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 05/01/2013] [Indexed: 11/19/2022] Open
Abstract
Background In schistosomiasis control programmes using mass chemotherapy, epidemiological and morbidity aspects of the disease need to be studied so as to monitor the impact of treatment, and make recommendations accordingly. These aspects were examined in the community of Musoli village along Lake Victoria in Mayuge district, highly endemic for Schistosoma mansoni infection. Methodology and Principal Findings A cross sectional descriptive study was undertaken in a randomly selected sample of 217 females and 229 males, with a mean age of 26 years (SD ±16, range 7–76 years). The prevalence of S. mansoni was 88.6% (95% CI: 85.6–91.5). The geometric mean intensity (GMI) of S. mansoni was 236.2 (95% CI: 198.5–460.9) eggs per gram (epg) faeces. Males had significantly higher GMI (370.2 epg) than females (132.6 epg) and age was also significantly associated with intensity of infection. Levels of water contact activities significantly influenced intensity of infection and the highest intensity of infection was found among people involved in fishing. However, organomegaly was not significantly associated with S. mansoni except for very heavy infection (>2000 epg). Liver image patterns C and D indicative of fibrosis were found in only 2.2% and 0.2%, respectively. S. mansoni intensity of infection was associated with portal vein dilation and abnormal spleen length. Anaemia was observed in 36.4% of the participants but it was not associated with S. mansoni infection intensity. Considering growth in children as one of the morbidity indicators of schistosomiasis, intensity of S. mansoni was significantly associated with stunting. Conclusion Although organ-related morbidity, with the exception of periportal fibrosis, and S. mansoni infections were highly prevalent, the two were only associated for individuals with very high infection intensities. These results contrast starkly with reports from Ugandan Lake Albert fishing communities in which periportal fibrosis is more prevalent. Schistosoma mansoni infection is one of the Neglected Tropical Diseases (NTDs) that perpetuate poverty, especially in Sub Saharan Africa. It is associated with hepatomegaly, splenomegaly or hepatosplenomegaly, liver fibrosis and anaemia. Control of schistosomiasis is now a priority in most endemic countries in Africa as a component of integrated control of NTDs using mass drug administration (MDA). Other than the new WHO strategic plan to eliminate schistosomiasis as a public health problem in WHO Africa region by 2020, the major target in the control of schistosomiasis has for a long time been reduction of its related morbidity. Epidemiological and morbidity studies are key in monitoring the impact of an intervention. However, epidemiology of schistosomiasis and its related morbidity have been shown to vary in different endemic areas and communities. We report on the epidemiology of S. mansoni infection and related morbidity in a community in Mayuge District along Lake Victoria in Uganda.
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Zongo D, Kabre BG, Dayeri D, Savadogo B, Poda JN. [Parasitological profile of two forms of schistosomiasis (urinary and intestinal forms) at ten sites in Burkina Faso (Sub-Saharan Africa country)]. C R Biol 2013; 336:317-9. [PMID: 23916210 DOI: 10.1016/j.crvi.2013.04.014] [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] [Indexed: 11/16/2022]
Abstract
In spite of great progress in schistosomiasis control during the last decade in Burkina Faso, this disease remains a public health concern in the country. Indeed, our study consisted of the analysis of parasitological data related to Schistosoma haematobium and Schistosoma mansoni and in malacological investigations. The prevalence rate of Schistosoma haematobium varies from 3.3% to 50.4% and from 3.3% to 39.1% for Schistosoma mansoni, but only in the western part of Burkina Faso. Schoolboys are more infested than girls, but the phenomenon is reversed in adults. Biomphalaria pfeifferi, Bulinus truncatus, Bulinus senegalensis and Bulinus globosus were collected during this study. Thus, the behavioral factors as well as the dynamics and the distribution of the intermediate mollusks play a major role in the persistence of the disease.
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Affiliation(s)
- Dramane Zongo
- Institut de recherche en sciences de la santé, Ouagadougou 03, Burkina Faso.
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Fulford AJ, Webster M, Ouma JH, Kimani G, Dunne DW. Puberty and Age-related Changes in Susceptibility to Schistosome Infection. ACTA ACUST UNITED AC 2013; 14:23-6. [PMID: 17040685 DOI: 10.1016/s0169-4758(97)01168-x] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent data from outbreaks of schistosomiasis in immunologically naive populations have refuelled the debate concerning the nature or existence of protective, acquired immunity to schistosomiasis in humans. Data from endemic communities provide some compelling evidence for an abrupt change in reinfection rates that coincides with puberty. We suggest that the hormonal changes of adrenarche may hold the key to understanding the relative resistance to infection found in adults.
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Affiliation(s)
- A J Fulford
- Division of Microbiology and Parasitology, Department of Pathology, University of Cambridge, Tennis Court Rd, Cambridge, UK CB2 1QP
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Impact of Schistosoma haematobium infection on urinary tract pathology, nutritional status and anaemia in school-aged children in two different endemic areas of the Niger River Basin, Mali. Acta Trop 2011; 120 Suppl 1:S142-50. [PMID: 21195046 DOI: 10.1016/j.actatropica.2010.12.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 12/13/2010] [Accepted: 12/20/2010] [Indexed: 12/31/2022]
Abstract
The aim of the present study was to contribute to define urinary schistosomiasis-related morbidity indicators and to understand the relationship between infection intensity and disease burden among school-aged children in different endemic areas of Mali. A cross sectional study was undertaken in two different endemic settings: Koulikoro district, along the river and Selingué dam area in the Niger River Basin in order to compare and describe morbidity related to Schistosoma haematobium infection. A total of 667 children aged 7-14 were enrolled in the study. Among these, 333 were from Koulikoro district (175 boys and 158 girls) and 334 from Selingué dam area (169 boys and 165 girls). The overall prevalence of S. haematobium in the two areas was 91.5%; Koulikoro (97.0%) and Selingué (85.9%) and this difference was significant after adjusting for age, sex and clustering within villages. Prevalence of heavy infection (≥ 50 eggs per 10 ml of urine), 57.6% in Koulikoro and 43.8% in Selingué, did not differ significantly after adjusting for age, sex and clustering within villages. The transmission of Schistosoma mansoni was mainly confined to Selingué dam area (12.5%) and was nearly absent in Koulikoro district (1.1%). Blood in urine was the most frequently reported clinical symptom, more common in Koulikoro (76.8%) than in Selingué (57.6%). In a multivariable logistic regression model adjusting for sex, age group, egg intensity category and clustering within villages, Selingué had higher prevalence of macro-haematuria, urinary tract pathology, upper urinary tract pathology and total pathology than Koulikoro, while micro-haematuria did not differ between the two areas. Morbidity measures increased to some extent with egg intensity category, especially micro-haematuria. The results obtained from this study are of importance for planning intervention as for monitoring and evaluation of control in different endemic settings in Mali.
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Sow S, de Vlas SJ, Stelma F, Vereecken K, Gryseels B, Polman K. The contribution of water contact behavior to the high Schistosoma mansoni Infection rates observed in the Senegal River Basin. BMC Infect Dis 2011; 11:198. [PMID: 21767372 PMCID: PMC3160997 DOI: 10.1186/1471-2334-11-198] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 07/18/2011] [Indexed: 11/29/2022] Open
Abstract
Background Schistosomiasis is one of the major parasitic diseases in the world in terms of people infected and those at risk. Infection occurs through contact with water contaminated with larval forms of the parasite, which are released by freshwater snails and then penetrate the skin of people. Schistosomiasis infection and human water contact are thus essentially linked, and more knowledge about their relationship will help us to develop appropriate control measures. So far, only few studies have related water contact patterns to infection levels. Methods We have conducted detailed direct water contact observations in a village in Northern Senegal during the first years of a massive Schistosoma mansoni outbreak to determine the role of human water contact in the extent of the epidemic. We quantified water contact activities in terms of frequency and duration, and described how these vary with age and sex. Moreover, we assessed the relationship between water contact- and infection intensity patterns to further elucidate the contribution of exposure to the transmission of schistosomiasis. Results This resulted in over 120,000 recorded water contacts for 1651 subjects over 175 observation days. Bathing was the main activity, followed by household activities. Frequency and duration of water contact depended on age and sex rather than season. Water contacts peaked in adolescents, women spent almost twice as much time in the water as men, and water contacts were more intense in the afternoon than in the morning, with sex-specific intensity peaks. The average number of water contacts per person per day in this population was 0.42; the average time spent in the water per person per day was 4.3 minutes. Conclusions The observed patterns of water contact behavior are not unusual and have been described before in various other settings in sub-Saharan Africa. Moreover, water contact levels were not exceptionally high and thus cannot explain the extremely high S. mansoni infection intensities as observed in Northern Senegal. Comparison with fecal egg counts in the respective age and sex groups further revealed that water contact levels did not unambiguously correspond with infection levels, indicating that factors other than exposure also play a role in determining intensity of infection.
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Affiliation(s)
- Seydou Sow
- Prince Leopold Institute of Tropical Medicine, Antwerp, Belgium
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Abstract
The past 30 years have seen research on the immunology of schistosomiasis move to encompass studies of responses in naturally exposed human populations, in addition to the studies in animal model systems. While animal systems still retain an important place in research on the immunology of schistosomiasis, recent debate has centred on aspects of human immunological responses that may or may not be associated with resistance or susceptibility to infection. In this article, Paul Hagan, Patricia Ndhlovu and David Dunne take stock of the present state of knowledge and offer their views on prospects for the future.
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Affiliation(s)
- P Hagan
- Division of Infection and Immunity, IBLS, University of Glasgow, Glasgow, UK G12 8QQ
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Meevissen MHJ, Balog CIA, Koeleman CAM, Doenhoff MJ, Schramm G, Haas H, Deelder AM, Wuhrer M, Hokke CH. Targeted glycoproteomic analysis reveals that kappa-5 is a major, uniquely glycosylated component of Schistosoma mansoni egg antigens. Mol Cell Proteomics 2011; 10:M110.005710. [PMID: 21372247 DOI: 10.1074/mcp.m110.005710] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycans present on glycoproteins from the eggs of the parasite Schistosoma mansoni are mediators of various immune responses of the human host, including T-cell modulation and granuloma formation, and they are the target of glycan-specific antibodies. Here we have analyzed the glycosylation of kappa-5, a major glycoprotein antigen from S. mansoni eggs using a targeted approach of lectin purification followed by mass spectrometry of glycopeptides as well as released glycans. We demonstrate that kappa-5 has four fully occupied N-glycosylation sites carrying unique triantennary glycans composed of a difucosylated and xylosylated core region, and immunogenic GalNAcβ1-4GlcNAc (LDN) termini. Furthermore, we show that the kappa-5 specific IgE antibodies in sera of S. mansoni-infected individuals are directed against the core region of the kappa-5 glycans. Whereas two previously analyzed immunomodulatory egg glycoproteins, IPSE/alpha-1 and omega-1, both express diantennary N-glycans with a difucosylated core and one or two Galβ1-4(Fucα1-3)GlcNAc (Lewis X) antennae, the kappa-5 glycosylation appears unique among the major soluble egg antigens of S. mansoni. The distinct structural and antigenic properties of kappa-5 glycans suggest a specific role for kappa-5 in schistosome egg immunogenicity.
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Affiliation(s)
- Moniek H J Meevissen
- Department of Parasitology, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
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Clerinx J, Van Gompel A. Schistosomiasis in travellers and migrants. Travel Med Infect Dis 2011; 9:6-24. [DOI: 10.1016/j.tmaid.2010.11.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 11/09/2010] [Accepted: 11/18/2010] [Indexed: 02/07/2023]
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Yami A, Kebede S, Mamo Y. Impact assessment of gilgel gibe hydroelectric dam on schitosomiasis: a cross sectional study in southwest ethiopia. Ethiop J Health Sci 2010; 20:129-36. [PMID: 22434971 PMCID: PMC3275834 DOI: 10.4314/ejhs.v20i2.69439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Intestinal schistosomiasis is prevalent in East Africa including Ethiopia. Constructed five years back, Gilgel Gibe dam is suspected to harbor the intermediate host for transmission of schistosomiasis. The objective of this study was to determine the prevalence of intestinal schistosomiasis and risk factors among school children. METHODS A comparative cross-sectional study was carried out in October 2008 in four Woredas bordering Gilgel Gibe dam, within 10 kilometers, and Bulbul, which is 30 Kms away from the dam. Children attending grades 1-8 in the schools located adjacent to the dam constituted the cases and those living in Bulbul constitute the controls. Using Epinfo version 6.0 for cross-sectional study, a sample size of 937 was determined. Sample size allocation was done 2:1 for cases and control. After interview, stool sample was collected and analyzed. Screening for the presence of intermediate host and physiochemical analyses of selected water bodies along the major water contact sites of the reservoir was also done Data were entered into computer and analyzed using SPSS for windows version 13.0.1. RESULTS Out of 624 sampled cases and 312 controls, 585 and 270 participated in the study giving a response rate of 93.8% and 86.5%, respectively. Four hundred seventy four (81.0% of the cases and 203 (75.2%) controls use latrine regularly. On stool examination, 406 (47.5%) children, 295 (50.4%) cases and 111 (41.1%) controls) were positive to intestinal parasites but only two children, both from the control groups, were positive for Schistosoma mansoni. The three river water samples on which malacological survey was done had similar physicochemical characteristics in many ways except high conductivity, pH and percent of dissolved oxygen concentration (milligram per liter) at one site where uninfected Biomphilaria Pfeifferi was found CONCLUSION The study revealed that schistosomiasis is not yet a problem at Gilgel-Gibe dam. But, continuous surveying is required as the intermediate host is prevalent, the water bodies are suitable for the intermediate host and cases of schistosomiasis are identified 30 kms away the dam, in control area.
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Affiliation(s)
- Alemeshet Yami
- Department of Internal Medicine, Jimma University, , corresponding author
| | - Sileshi Kebede
- Department of Microbiology and Parasitology, Jimma University
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17
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Yazdanbakhsh M, Sacks DL. Why does immunity to parasites take so long to develop? Nat Rev Immunol 2010; 10:80-1. [PMID: 20183893 DOI: 10.1038/nri2673] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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18
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Balog CIA, Mayboroda OA, Wuhrer M, Hokke CH, Deelder AM, Hensbergen PJ. Mass spectrometric identification of aberrantly glycosylated human apolipoprotein C-III peptides in urine from Schistosoma mansoni-infected individuals. Mol Cell Proteomics 2010; 9:667-81. [PMID: 20071361 DOI: 10.1074/mcp.m900537-mcp200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Schistosomiasis is a parasitic infection caused by Schistosoma flatworms, prime examples of multicellular parasites that live in the mammalian host for many years. Glycoconjugates derived from the parasite have been shown to play an important role in many aspects of schistosomiasis, and some of them are present in the circulation of the host. The aim of this study was to identify novel glycoconjugates related to schistosomiasis in urine of Schistosoma mansoni-infected individuals using a combination of glycopeptide separation techniques and in-depth mass spectrometric analysis. Surprisingly, we characterized a heterogeneous population of novel aberrantly O-glycosylated peptides derived from the C terminus of human apolipoprotein C-III (apoC-III) in urine of S. mansoni-infected individuals that were not detected in urine of non-infected controls. The glycan composition of these glycopeptides is completely different from what has been described previously for apoC-III. Most importantly, they lack sialylation and display a high degree of fucosylation. This study exemplifies the potential of mass spectrometry for the identification and characterization of O-glycopeptides without prior knowledge of either the glycan or the peptide sequence. Furthermore, our results indicate for the first time that as a result of S. mansoni infection the glycosylation of a host protein is altered.
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Affiliation(s)
- Crina I A Balog
- Department of Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands.
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19
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Moné H, Ibikounlé M, Massougbodji A, Mouahid G. Human Schistosomiasis in the Economic Community of West African States. ADVANCES IN PARASITOLOGY 2010. [DOI: 10.1016/s0065-308x(10)71001-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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20
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Campbell G, Noble LR, Rollinson D, Southgate VR, Webster JP, Jones CS. Low genetic diversity in a snail intermediate host (Biomphalaria pfeifferi Krass, 1848) and schistosomiasis transmission in the Senegal River Basin. Mol Ecol 2009; 19:241-56. [PMID: 20025653 DOI: 10.1111/j.1365-294x.2009.04463.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Population genetic perturbations of intermediate hosts, often a consequence of human pressure on environmental resources, can precipitate unexpectedly severe disease outbreaks. Such disturbances are set to become increasingly common following range changes concomitant with climate shifts, dwindling natural resources and major infrastructure changes such as hydroprojects. Construction of the Diama dam in the Senegal River Basin (SRB) reduced river salinity, enabling the freshwater snail intermediate host Biomphalaria pfeifferi to rapidly expand its distribution. A serious public health problem ensued, with an epidemic of intestinal schistosomiasis occurring in the previously schistosome-free Richard-Toll region within 2 years. The current study aimed to assess the population variability of B. pfeifferi in the SRB, and speculate upon its subsequent impact on host-parasite interactions following such engineered ecological change. Genetic variation at nine polymorphic microsatellite loci revealed little population differentiation in SRB snails compared with those from natural habitats in Zimbabwe, where Schistosoma mansoni transmission is much lower. 'Open' SRB habitats are associated with greater water contact, smaller population sizes and less genetic diversity, with sites downstream of Richard-Toll showing greater inter- and intrapopulation variation, concomitant with less frequent human contact. These observations may be explained by rapid expansion into pristine habitat selecting for high fecundity genotypes at the expense of schistosome resistance, presenting S. mansoni with genetically homogenous highly fecund susceptible populations around the focal point, promoting development of a highly compatible host-parasite relationship. Longitudinal study of such systems may prove important in predicting public health risks engendered by future environmental engineering projects.
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Affiliation(s)
- G Campbell
- General Medical Council, St James's Buildings, 79 Oxford Street, Manchester, M1 6FQ, UK
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21
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Bethony JM, Diemert DJ, Oliveira SC, Loukas A. Can schistosomiasis really be consigned to history without a vaccine? Vaccine 2008; 26:3373-6. [PMID: 18513839 DOI: 10.1016/j.vaccine.2008.04.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 03/17/2008] [Accepted: 04/03/2008] [Indexed: 12/27/2022]
Abstract
Recently, considerable enthusiasm has been expressed for expanding and combining control efforts for neglected tropical diseases (NTDs). While these efforts are laudable, the drugs in question require repeated mass administration for indefinite periods of time, and their use to achieve eradication is fraught with challenges. Mass drug administration is unlikely to be effective in isolation, and should not proceed without concurrent control methods, such as vaccines. Schistosomiasis is one of the most important NTDs, and one whose effective control is unlikely in the absence of improved sanitation and a vaccine. Recent advances in biotechnologies have enhanced antigen discovery and new molecules that show promise as recombinant vaccines are being reported. Funding bodies supporting research into the control of schistosomiasis should invest not only in mass drug administration but also in the development of new control strategies, including the development of vaccines.
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Abstract
Schistosomiasis is a common intravascular trematode infection. The snail/human lifecycle is illustrated. Travellers who acquire the infection are often asymptomatic, but nearly always give a history of fresh water exposure in endemic countries when asked. The various manifestations of symptomatic schistosomiasis are described, including the rare but important complication of neuroschistosomiasis. Guidelines for diagnostic tests, treatment with praziquantel and management of complications are given. Prospects for disease control in endemic countries by improvement in public health and mass treatment are discussed. Various vaccines are in development, but none are in clinical use yet.
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Affiliation(s)
- Tom J Blanchard
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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23
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Vereecken K, Naus CWA, Polman K, Scott JT, Diop M, Gryseels B, Kestens L. Associations between specific antibody responses and resistance to reinfection in a Senegalese population recently exposed to Schistosoma mansoni. Trop Med Int Health 2007; 12:431-44. [PMID: 17313515 DOI: 10.1111/j.1365-3156.2006.01805.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We examined associations between schistosome-specific antibody responses and reinfection in Senegalese individuals recently exposed to Schistosoma mansoni. The effects of treatment, age, intensity of infection and duration of exposure on schistosome-specific antibody responses were also investigated by comparing immune responses in individuals exposed for less than 3 years with responses in people exposed for more than 8 years. All individuals were bled before treatment as well as 6 and 12 weeks after. We used a statistical model that included interaction terms between time, age, infection intensity and duration of exposure. The overall patterns of most specific antibody responses by age were similar to those previously published for S. mansoni, Schistosoma japonicum and Schistosoma haematobium infections in different endemic areas. In general, a boost in specific antibody responses against adult worm antigen (SWA) was observed at 6 weeks after treatment whereas the majority of isotype responses against egg antigen (SEA) were not affected by treatment. Our analysis showed that the effect of treatment on schistosome-specific antibody responses is influenced by age, infection intensity and duration of exposure. We found no evidence that treatment matures the specific antibody response of children recently infected with S. mansoni. Our results indicate that the build-up of potentially protective immunoglobulin E (IgE) responses was associated with duration of exposure, or, in other words, experience of infection. Interestingly, in recently exposed individuals there was a significant association between IgA responses to SWA and resistance to reinfection. Resistance to reinfection and production of IgA-SWA was associated with adulthood independently of exposure patterns, suggesting that susceptibility to S. mansoni and the development of protective immune responses is age-dependent.
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Affiliation(s)
- Kim Vereecken
- Prince Leopold Institute of Tropical Medicine, Antwerp, Belgium
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24
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Doenhoff MJ, Pica-Mattoccia L. Praziquantel for the treatment of schistosomiasis: its use for control in areas with endemic disease and prospects for drug resistance. Expert Rev Anti Infect Ther 2006; 4:199-210. [PMID: 16597202 DOI: 10.1586/14787210.4.2.199] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Praziquantel became available for the treatment of schistosomiasis and other trematode-inflicted diseases in the 1970s. It was revolutionary because it could be administered orally and had very few unwanted side effects. As a result of marked reductions in the price of praziquantel, the rate at which it is used has accelerated greatly in recent years. For the foreseeable future it will be the mainstay of programs designed to control schistosome-induced morbidity, particularly in sub-Saharan Africa where schistosomiasis is heavily endemic. There is currently no evidence to suggest that any schistosomes have developed resistance to praziquantel as a result of its widespread use. Nevertheless, while resistance may not pose an obvious or immediate threat to the usefulness of praziquantel, complacency and a failure to monitor developments may have serious consequences in the longer term since it will be the only drug that is readily available for large-scale treatment of schistosomiasis.
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Affiliation(s)
- Michael J Doenhoff
- University of Wales Bangor, School of Biological Sciences, Bangor, Gwynedd LL576 2UW, UK.
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25
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Shaohong L, Kumagai T, Qinghua A, Xiaolan Y, Ohmae H, Yabu Y, Siwen L, Liyong W, Maruyama H, Ohta N. Evaluation of the anthelmintic effects of artesunate against experimental Schistosoma mansoni infection in mice using different treatment protocols. Parasitol Int 2005; 55:63-8. [PMID: 16290045 DOI: 10.1016/j.parint.2005.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 10/05/2005] [Indexed: 11/21/2022]
Abstract
The therapeutic effects of artesunate against experimental Schistosoma mansoni infection in mice were analyzed. Previous studies showed that artesunate is highly effective against S. japonicum infection, but the action of this drug against S. mansoni remained uncovered. The present study examines the optical conditions for artesunate against S. mansoni and evaluates the effects of inhibiting the sexual maturation of adult worms. Mice infected with S. mansoni were orally administered with artesunate according to different schedules. Four consecutive administrations of 300 mg/kg of artesunate at 2-week intervals conferred almost total protection without the development of pathological lesions in the liver. The significant reduction in the number of eggs produced by surviving worms and the status of egg maturation suggested that artesunate inhibits sexual maturation. Electron microscopy revealed that artesunate caused morphological damage, especially on the worm tegument. Artesunate was also very effective in iron-deficient mice. Furthermore, the efficacy of artesunate was equal to or better than that of artemether against S. japonicum infection. Considering that artemether is more toxic, artesunate is currently one of the most efficient drugs against immature S. mansoni.
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Affiliation(s)
- Lu Shaohong
- Institute of Parasitic Diseases, Zhejiang Academy of Medical Sciences, Hangzhou 310013, China; Department of Molecular Parasitology, Nagoya City University Graduate School of Medical Sciences, Nagoya 467-8601, Japan
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26
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Affiliation(s)
- A E Butterworth
- Department of Pathology, Tennis Court Road, Cambridge, UK CB2 I QP
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27
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Affiliation(s)
- B Gryseels
- Department of Parasitology, Medical Faculty, University of Leiden, PB 9605, 2300 RC Leiden, The Netherlands
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28
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Cioli D, Botros SS, Wheatcroft-Francklow K, Mbaye A, Southgate V, Tchuenté LAT, Pica-Mattoccia L, Troiani AR, El-Din SHS, Sabra ANA, Albin J, Engels D, Doenhoff MJ. Determination of ED50 values for praziquantel in praziquantel-resistant and -susceptible Schistosoma mansoni isolates. Int J Parasitol 2004; 34:979-87. [PMID: 15217737 DOI: 10.1016/j.ijpara.2004.05.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2004] [Revised: 05/03/2004] [Accepted: 05/03/2004] [Indexed: 11/21/2022]
Abstract
The dose of praziquantel required to kill 50% of adult worms in vivo (i.e. the ED50) was estimated for nine different isolates of Schistosoma mansoni in infected mice. Four of the isolates were selected because they had not knowingly been in contact with the drug (i.e. they were putatively praziquantel-susceptible). Five putatively praziquantel-resistant isolates were chosen because they had been selectively bred for drug-resistance in the laboratory and/or had previously been shown to be relatively resistant to praziquantel in the field. The work was performed in three laboratories in different countries using pre-agreed and comparable experimental protocols. All four praziquantel-susceptible isolates had ED50s estimated to be <100 mg/kg (mean=70+/-7 SD; median=68), while all five putatively praziquantel-resistant isolates had estimated ED50s >100 mg/kg (mean=209+/-48 SD; median=192). Thus, the five praziquantel-resistant isolates, including two that had been subjected to drug pressure during more than 20 passages in mice, had drug ED50s that were approximately three times as great as those of the praziquantel-susceptible isolates. Two of the five isolates in the putatively resistant group had previously been passaged 15 or more times in mice without administration of drug-pressure, but had ED50s consistent with the other three isolates in the group, indicating that the trait of praziquantel-resistance did not necessarily impair biological fitness during laboratory passage. The protocols used here to estimate the praziquantel ED50s of S. mansoni isolates should be useful for establishing and monitoring the drug susceptibility/resistance profiles of parasite isolates freshly obtained from endemic areas, particularly those in which increased usage of the drug is likely to occur.
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Affiliation(s)
- Donato Cioli
- Institute of Cell Biology, 32 Via Ramarini, 00016 Monterotondo, Rome, Italy
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29
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Robijn MLM, Wuhrer M, Kornelis D, Deelder AM, Geyer R, Hokke CH. Mapping fucosylated epitopes on glycoproteins and glycolipids ofSchistosoma mansonicercariae, adult worms and eggs. Parasitology 2004; 130:67-77. [PMID: 15700758 DOI: 10.1017/s0031182004006390] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The developmental expression of the antigenic fucosylated glycan motifs Fucα1-3GalNAcβ1-4GlcNAc (F-LDN), Fucα1-3GalNAcβ1-4(Fucα1-3)GlcNAc (F-LDN-F), GalNAcβ1-4(Fucα1-3)GlcNAc (LDN-F), Galβ1-4(Fucα1-3)GlcNAc (Lewis X), and GalNAcβ1-4(Fucα1-2Fucα1-3)GlcNAc (LDN-DF) inSchistosoma mansonicercariae, adult worms and eggs, was surveyed using previously defined anti-carbohydrate monoclonal antibodies (mAbs). Lewis X was found both on glycolipids and glycoproteins, yet with completely different expression patterns during the life-cycle: on glycolipids, Lewis X was mainly found in the cercarial stage, while protein-conjugated Lewis X was mainly present in the egg stage. Also protein-conjugated LDN-F and LDN-DF were most highly expressed in the egg-stage. On glycolipids LDN-DF was found in all three examined stages, whereas LDN-F containing glycolipids were restricted to adult worms and eggs. The motifs F-LDN and F-LDN-F were found both on glycoproteins and glycolipids of the cercarial and egg stage, while in the adult stage, they appeared to occur predominantly on glycolipids. Immunofluorescence assays (IFA) showed that these F-LDN and F-LDN-F containing glycolipids were localized in a yet undefined duct or excretory system of adult worms. Murine infection serum showed major reactivity with this adult worm duct-system, which could be fully inhibited by pre-incubation with keyhole limpet haemocyanin (KLH). Clearly, the use of defined mAbs provides a quick and convenient way to map expression profiles of carbohydrate epitopes.
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Affiliation(s)
- M L M Robijn
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
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30
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Increase of malaria attacks among children presenting concomitant infection by Schistosoma mansoni in Senegal. Malar J 2004; 3:43. [PMID: 15544703 PMCID: PMC538284 DOI: 10.1186/1475-2875-3-43] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Accepted: 11/15/2004] [Indexed: 11/10/2022] Open
Abstract
Helminthic infections concomitant with malaria are common in inter-tropical areas. A recent study showed that mice co-infected with Schistosoma mansoni and Plasmodium chabaudi develop higher P. chabaudi parasitaemia and had a higher mortality rate. This important observation deserved to be further investigated among human populations. Malaria attacks were recorded in 512 children aged 6–15 years living in Richard Toll (Northern Senegal) among whom 336 were infected by S. mansoni, and 175 were not. The incidence rate of malaria attacks was significantly higher among S. mansoni-infected individuals, particularly those carrying the highest worm loads, as compared to uninfected subjects (26.6% versus 16,4 %). In contrast, the rate of malaria attacks was lower, without reaching significance, in medium grade S. mansoni infections. Thus, infection by S. mansoni affects susceptibility to malaria, but this can vary according to the intensity of parasite load. The immunological mechanisms underlying this dual effect need to be further explored.
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31
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Bogers JJPM, Chatterjee S, Jacobs W, Fallon PG, Dunne DW, Langermans JAM, Deelder AM, Thomas AW, Van Marck EAE. Juvenile rhesus monkeys have more colonic granulomas than adults after primary infection with Schistosoma mansoni. Virchows Arch 2004; 445:285-91. [PMID: 15517371 DOI: 10.1007/s00428-004-1083-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 06/16/2004] [Indexed: 11/26/2022]
Abstract
Adults and children have differences in their susceptibility to schistosomiasis. Whether this age-dependent innate susceptibility influences parasite-caused granulomogenesis is difficult to assess in humans. Therefore, we exposed juvenile and adult female rhesus monkeys to primary infection with Schistosoma mansoni. Hepatic and intestinal granuloma formation was observed in both pre-pubescent and adult monkeys. Two distinct stages of granulomas were discerned, the exudative and the productive stage. In the intestine, more granulomas were generated in the colon than in the ileum. In contrast to the adult animals, the juvenile rhesus monkeys had higher numbers of colonic granulomas, these higher numbers being predominantly of the more advanced productive stage. Juvenile animals had a statistically non-significant increased worm burden. These results suggest that juvenile rhesus monkeys have a significantly more intense and advanced colonic response towards entrapped S. mansoni eggs after primary schistosome infections and, thereby, are more susceptible to parasite infection.
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Affiliation(s)
- Johannes J P M Bogers
- Laboratory of Pathology, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium
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Garba A, Labbo R, Tohon Z, Sidiki A, Djibrilla A. Emergence of Schistosoma mansoni in the Niger River valley, Niger. Trans R Soc Trop Med Hyg 2004; 98:296-8. [PMID: 15109553 DOI: 10.1016/s0035-9203(03)00070-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2003] [Revised: 09/26/2003] [Accepted: 10/01/2003] [Indexed: 11/29/2022] Open
Abstract
Urinary and intestinal schistosomiasis are both endemic in Niger with a dominance of Schistosoma haematobium. This study pointed out the appearance of the infection to S. mansoni in the Niger River valley, where it was until then unknown in Niger. In one year the prevalence increased from 5.9 to 19.5%.
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Affiliation(s)
- Amadou Garba
- Centre de Recherches Médicales et Sanitaires (CERMES), Ministry of Health, B.P. 10887, Niamey, Niger.
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33
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Chatterjee S, Mbaye A, Alfidja AT, Weyler J, Scott JT, Van Damme P, Van De Vijver K, Deelder A, Van Marck EAE. Circulating levels of the neuropeptide hormone somatostatin may determine hepatic fibrosis in Schistosoma mansoni infections. Acta Trop 2004; 90:191-203. [PMID: 15177146 DOI: 10.1016/j.actatropica.2003.12.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2003] [Revised: 11/26/2003] [Accepted: 12/17/2003] [Indexed: 11/24/2022]
Abstract
The neuropeptide hormone somatostatin reduces fibrosis and Schistosoma-caused clinical morbidity in the rodent model. In our study we aimed to delineate an association between fibrosis and the inability to generate critical levels of endogenous somatostatin in S. mansoni infected subjects. In June 2001, 85 subjects from the district dispensary at Richard Toll in the Medical Region of Saint-Louis, Senegal, were selected. Fifty-seven subjects were infected with S. mansoni of whom 32 were suffering from severe morbidity (SM). Twenty-eight subjects showed an inactive disease status with no evident infection at the actual time of study. All subjects were classified according to age, sex, occupation, height, weight, and parasite eggs per gram. All 85 participated in a water contact and morbidity questionnaire, underwent a clinical examination and donated 5ml of peripheral blood for detecting plasma levels of somatostatin. Ultrasonography detected fibrosis grade in all the subjects. To address whether inherent somatostatin levels determined clinically evident disease severity (epg, hepatomegaly, splenomegaly, hematemesis, ascites), the mean somatostatin values of the inactive disease status group and severe morbidity group were compared. Low somatostatin levels were depicted in subjects with severe morbidity symptoms associated with schistosomiasis as compared to exposed but inactive disease status subjects residing in the same region. Logistic regression analysis indicated that with decreasing somatostatin values the probability of severe morbidity increased with age being a confounding factor. To address whether inherent somatostatin levels determined fibrosis and if this association was significant, plasma somatostatin levels of non-fibrotics (ultrasonographic grading A), and fibrotics (ultrasonographic grading B-E) were compared. In all age groups as well as in adults alone, mean somatostatin levels were higher in the non-fibrotic group as compared to the fibrotics group, the difference being significant. The group B comprised of borderline fibrotic cases, therefore a separate analysis was done between groups A (non-fibrotics) and groups C, D (confirmed fibrotics). Mean somatostatin values were higher in the non-fibrotic group as compared to the fibrotics group, the difference being borderline significant. In schistosomiasis patients, circulating levels of somatostatin by binding to hepatic stellate cells (HSC) may modulate fibrosis. This phenomenon is regulated by age whereas gender and prior treatment have no effect on this association. Host specific somatostatin levels may create a 'preset environment' status that can determine progression to severe fibrosis.
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Affiliation(s)
- Shyama Chatterjee
- Pathology Unit, Department of Medicine, University of Antwerp, Universiteitsplein 1, B 2610 Antwerp, Belgium.
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34
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Sow S, de Vlas SJ, Mbaye A, Polman K, Gryseels B. Low awareness of intestinal schistosomiasis in northern Senegal after 7 years of health education as part of intense control and research activities. Trop Med Int Health 2003; 8:744-9. [PMID: 12869097 DOI: 10.1046/j.1365-3156.2003.01080.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We evaluated the awareness of and knowledge about intestinal schistosomiasis in a highly infected rural community of northern Senegal where a variety of health information and education activities had taken place for 7 years as a component of different research and control programmes. As the infection had been introduced only recently, an initial 'zero' knowledge can be assumed. Most of the health education activities had been performed with adapted messages through local health and community workers. By a questionnaire, 566 individuals were asked simple questions on symptoms, mode of transmission, the sources of information and health-seeking behaviour. About 86% of the respondents stated that they knew what schistosomiasis was, and 92% that in case of illness they would seek treatment at the health centre. However, only half of the people accurately quoted symptoms associated with intestinal schistosomiasis: diarrhoea, abdominal pain and bloody stools. The majority of respondents realized that the disease was somehow linked with water and (lack of) hygiene, but only 44% of respondents reported water contact as the source of infection. Ultimately, only 30% of the respondents gave adequate answers about both symptoms and mode of transmission. We conclude that even intense and long-lasting education efforts for a specific and straightforward problem as schistosomiasis are not enough to have profound impact on the knowledge of rural traditional communities.
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Affiliation(s)
- Seydou Sow
- Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium.
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Scott JT, Diakhaté M, Vereecken K, Fall A, Diop M, Ly A, De Clercq D, de Vlas SJ, Berkvens D, Kestens L, Gryseels B. Human water contacts patterns in Schistosoma mansoni epidemic foci in northern Senegal change according to age, sex and place of residence, but are not related to intensity of infection. Trop Med Int Health 2003; 8:100-8. [PMID: 12581433 DOI: 10.1046/j.1365-3156.2003.00993.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In an epidemic focus in northern Senegal, adults had lower intensities of infection than adolescents, a phenomenon that could not be attributed to immunity acquired over the previous 10-15 years of exposure to the parasite because all age groups had had the same number of years' experience of the worm. This article considers whether this pattern could have been because of higher levels of exposure to the parasite in younger age groups. Personal contact with infected water was recorded using a questionnaire in Schistosoma mansoni foci not more than 3 years old and in another, 10-year-old focus. Many aspects of contact (e.g. frequency, duration or time of day of contact) may contribute to the number of encounters with infective cercariae (true exposure), so various assumptions regarding the relationship between water contact and true exposure were tested resulting in a range of exposure indices. People reported a mean of 4.4 separate contacts, and spent a median of 57 min per day in water. Patterns of water contact differed depending on the exposure index used, e.g. considering duration, males spent a longer time in water than females (P < 0.001). But using frequency, females had more contacts with water than males in most villages (P < 0.001). Generally, exposure levels dropped as people become aged (P < 0.001) and residents of the older focus were more exposed than residents of other foci (P < 0.002). Intensity of (re)infection was not related to exposure either alone or in models incorporating age, sex and/or village irrespective of the index used. There is therefore evidence that age, sex and place of residence determine exposure but none to suggest that exposure had an influence on the relationship between these factors and intensity of infection. We propose therefore that in this population other factors have principal importance in determining intensity of infection.
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Affiliation(s)
- J T Scott
- Institute of Tropical Medicine, Antwerp, Belgium.
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Lawn SD, Lucas SB, Chiodini PL. Case report: Schistosoma mansoni infection: failure of standard treatment with praziquantel in a returned traveller. Trans R Soc Trop Med Hyg 2003; 97:100-1. [PMID: 12886814 DOI: 10.1016/s0035-9203(03)90038-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heavy reliance upon praziquantel for the treatment of schistosomiasis raises concerns over potential development of drug resistance. We describe a British traveller who acquired Schistosoma mansoni infection in East Africa and in whom repeated standard 40 mg/kg doses of praziquantel failed to clear the infection despite no opportunity for reinfection.
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Polman K, Stelma FF, Le Cessie S, De Vlas SJ, Falcão Ferreira STM, Talla I, Deelder AM, Gryseels B. Evaluation of the patterns of Schistosoma mansoni infection and re-infection in Senegal, from faecal egg counts and serum concentrations of circulating anodic antigen. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96:679-89. [PMID: 12537629 DOI: 10.1179/000349802125001708] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Infection and re-infection patterns were evaluated in a recent Schistosoma mansoni focus in northern Senegal, by determining concentrations of serum circulating anodic antigen (CAA), as a measure of worm burden, and counting eggs in faeces before, 6 or 12 weeks and 1 year after praziquantel treatment in two subsequent cohorts (cohort A and B). No differences in egg counts and CAA concentrations or their relationship were found between the cohorts, which were examined 2 years apart. Within both cohorts, CAA concentrations showed the same, typical, age-related patterns as egg counts, with a peak in children and a strong decline in adults. These trends were apparent both before and 1 year after treatment. The results indicate that an age-related resistance to infection and to re-infection has been firmly established, at a steady level, in the recent S. mansoni focus investigated, with no indication of a gradual development of immunity or anti-fecundity immunity over a period of 2 years. Both shortly and 1 year after treatment, the decrease in egg counts was stronger than that in CAA concentrations, indicating that that there had been a reduction in worm fecundity after treatment. The possibility that praziquantel may induce anti-fecundity immunity has important implications for the use and interpretation of the results of (egg-count-based) re-infection studies designed to follow the development of naturally acquired immunity.
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Affiliation(s)
- K Polman
- Department of Parasitology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
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Sow S, de Vlas SJ, Engels D, Gryseels B. Water-related disease patterns before and after the construction of the Diama dam in northern Senegal. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96:575-86. [PMID: 12396320 DOI: 10.1179/000349802125001636] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ecological changes caused by projects for the development of water resources are known to affect the epidemiology of water-related diseases. The effects of the construction of the Diama dam (completed in 1986) in the Senegal River on the epidemiology of malaria, urinary and intestinal schistosomiasis, diarrhoea and dysentery were investigated in four districts in northern Senegal. To make allowance for any general trend in reported morbidity (caused by changes in demography or the healthcare system), the numbers of cases of these illnesses reported by the basic healthcare facilities before and after the completion of the dam were compared with those of respiratory disease. Prior to the construction of the dam, malaria was the most encountered water-related disease in the medical records of all districts, followed by diarrhoea, dysentery and urinary schistosomiasis. This order remained the same after the completion of the dam. Despite the optimism of health-assessment reports prepared prior to the construction of the Diama dam, the unexpected appearance and spread of intestinal schistosomiasis as well as an increase in the incidence of urinary schistosomiasis have aggravated public health in the Senegal River basin. It remains to be judged whether the economic benefits of the dam will counterbalance its adverse effects.
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Affiliation(s)
- S Sow
- Helminthology Unit, Department of Parasitology, Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, B-2000 Antwerp, Belgium.
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Cooper PJ. Can intestinal helminth infections (geohelminths) affect the development and expression of asthma and allergic disease? Clin Exp Immunol 2002; 128:398-404. [PMID: 12067292 PMCID: PMC1906269 DOI: 10.1046/j.1365-2249.2002.01908.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2002] [Indexed: 11/20/2022] Open
Affiliation(s)
- P J Cooper
- Department of Infectious Diseases, St George's Hospital Medical School, London, UK.
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van der Werf MJ, de Vlas SJ, Looman CWN, Nagelkerke NJD, Habbema JDF, Engels D. Associating community prevalence of Schistosoma mansoni infection with prevalence of signs and symptoms. Acta Trop 2002; 82:127-37. [PMID: 12020885 DOI: 10.1016/s0001-706x(02)00007-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Information on the prevalence of morbidity is needed for re-calculation of the Global Burden of Disease (WHO) due to Schistosoma mansoni. This study presents a statistical association which can be used to predict the prevalence of morbidity from the prevalence of S. mansoni in a community. We collected data from field studies reporting prevalence of infection and prevalence of morbidity. Data on infection prevalence were standardised to a default diagnostic sensitivity (i.e. Kato-Katz technique 41.7 mg). The data were described by an expression related to logistic regression. We determined associations between prevalence of infection and prevalence of early morbidity (diarrhoea, blood in stool and abdominal pain), hepatosplenic morbidity and late morbidity (haematemesis and ascitis). Diarrhoea and blood in stool due to S. mansoni infection mainly occurs in communities with a high prevalence of infection. An influence on hepatosplenic morbidity is already present at low community prevalence of infection. For the aspecific symptom abdominal pain we did not find an association.
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Affiliation(s)
- Marieke J van der Werf
- Department of Public Health, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR, Rotterdam, The Netherlands.
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Cooper P, Nutman T. IgE and Its Role in Parasitic Helminth Infection. IGE AND ANTI-IGE THERAPY IN ASTHMA AND ALLERGIC DISEASE 2002. [DOI: 10.1201/b14035-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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van der Werf MJ, Mbaye A, Sow S, Gryseels B, de Vlas SJ. Evaluation of staff performance and material resources for integrated schistosomiasis control in northern Senegal. Trop Med Int Health 2002; 7:70-9. [PMID: 11851957 DOI: 10.1046/j.1365-3156.2002.00823.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND A project to improve integrated control of schistosomiasis in the primary health care system of northern Senegal was implemented from February 1995 until September 1999, shortly after a Schistosoma mansoni outbreak. The activities included additional training of doctors and nurses in symptom-based treatment and making praziquantel (PZQ) available for an affordable price. OBJECTIVE To investigate staff performance and the availability and costs of diagnostic materials and PZQ at the end of this intervention project. METHODS We performed structured interviews with staff from 55 health care facilities in five districts. RESULTS Respondents from 23 health care facilities reported both S. haematobium and S. mansoni in the coverage area, 32 reported only S. haematobium and three only S. mansoni. The average cost to patients for consultation, diagnosis, treatment and transportation to a referral health care facility was approximately 1.60 Euro. Fifty-seven per cent of the health care facilities with reported S. haematobium in the coverage area treated patients presenting with haematuria on symptoms; 56% of the health care facilities with reported S. mansoni in the coverage area treated patients presenting with blood in stool on symptoms. Thirteen per cent performed a diagnostic test for patients presenting with haematuria and 12% for patients presenting with blood in stool. The remainder, approximately one-third of the health care facilities, referred their patients to another facility for a diagnostic test. Implementation of symptom-based treatment in all health care facilities will reduce the total costs by 0.43 Euro (29%) for patients infected with S. haematobium and 0.78 Euro (46%) for patients infected with S. mansoni. Of the 53 health care facilities with schistosomiasis in their area, 37 had PZQ in stock of which 33 (88%) sold PZQ for the recommended retail price of 0.15 Euro per tablet (or 0.60 Euro per course of four tablets) or lower. CONCLUSION Four years after the start of the intervention project, patients presenting with schistosomiasis related symptoms can generally expect proper diagnosis and treatment at all levels of the health care system in Northern Senegal, either at the initial visited health care facility or after referral. However, a further reduction of the total costs of treatment is still possible by a better implementation of symptom-based treatment and further reduction of the costs of PZQ.
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Gryseels B, Mbaye A, De Vlas SJ, Stelma FF, Guissé F, Van Lieshout L, Faye D, Diop M, Ly A, Tchuem-Tchuenté LA, Engels D, Polman K. Are poor responses to praziquantel for the treatment of Schistosoma mansoni infections in Senegal due to resistance? An overview of the evidence. Trop Med Int Health 2001; 6:864-73. [PMID: 11703840 DOI: 10.1046/j.1365-3156.2001.00811.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This paper summarizes and concludes in-depth field investigations on suspected resistance of Schistosoma mansoni to praziquantel in northern Senegal. Praziquantel at 40 mg/kg usually cures 70-90% of S. mansoni infections. In an initial trial in an epidemic S. mansoni focus in northern Senegal, only 18% of the cases became parasitologically negative 12 weeks after treatment, although the reduction in mean egg counts was within normal ranges (86%). Among other hypotheses to explain the observed low cure rate in this focus, the possibility of drug resistance or tolerance had to be considered. Subsequent field trials with a shorter follow-up period (6-8 weeks) yielded cure rates of 31-36%. Increasing the dose to 2 x 30 mg/kg did not significantly improve cure rates, whereas treatment with oxamniquine at 20 mg/kg resulted in a normal cure rate of 79%. The efficacy of praziquantel in this focus could be related to age and pre-treatment intensity but not to other host factors, including immune profiles and water contact patterns. Treatment with praziquantel of individuals from the area residing temporarily in an urban region with no transmission, and re-treatment after 3 weeks of non-cured individuals within the area resulted in normal cure rates (78-88%). The application of an epidemiological model taking into account the relation between egg counts and actual worm numbers indicated that the low cure rates in this Senegalese focus could be explained by assuming a 90% worm reduction after treatment with praziquantel; in average endemic situations, such a drug efficacy would result in normal cure rates. Laboratory studies by others on the presence or absence of praziquantel resistance in Senegalese schistosome strains have so far been inconclusive. We conclude that there is no convincing evidence for praziquantel-resistant S. mansoni in Senegal, and that the low cure rates can be attributed to high initial worm loads and intense transmission in this area.
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Affiliation(s)
- B Gryseels
- Institute of Tropical Medicine, Antwerp, Belgium.
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Polman K, Stelma FF, De Vlas SJ, Sow S, Fathers L, Le Cessie S, Talla I, Deelder AM, Gryseels B. Dynamics of egg counts and circulating antigen levels in a recent Schistosoma mansoni focus in northern Senegal. Trop Med Int Health 2001; 6:538-44. [PMID: 11469948 DOI: 10.1046/j.1365-3156.2001.00742.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serum circulating anodic antigen (CAA) levels were compared with faecal egg counts in four subsequent population samples, randomly selected at 8-month intervals, in a recent Schistosoma mansoni focus in northern Senegal. In all four samples, antigen levels showed the same age-intensity profiles as egg counts, with a strong decline in adults. Also across population samples, a consistent relationship was found between egg counts and antigen levels. Assuming the level of CAA to be a direct reflection of worm burden, these findings support the idea that the observed egg count patterns and levels indeed reflect dynamics of worm burdens, and not of egg excretion or worm fecundity. Remarkably similar levels of both egg counts and CAA were observed in the first and last sample, collected in the same season (August--September), but 2 years apart. This suggests that a steady state of S. mansoni infection had already been reached shortly after the onset of the epidemic in this focus (3 years). Significantly lower infection levels were found in the intermediate population samples collected in January and April. The differences in infection levels across the four population samples may be because of seasonal transmission patterns. They would indicate a substantial turnover of worm populations, with an estimated average life span of only 7 months, probably less, in this recently emerged, intense S. mansoni focus.
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Affiliation(s)
- K Polman
- Department of Parasitology, Leiden University Medical Centre, Leiden, The Netherlands.
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Terhell AJ, Haarbrink M, Abadi K, Maizels RM, Yazdanbakhsh M, Sartono E. Adults acquire filarial infection more rapidly than children: a study in Indonesian transmigrants. Parasitology 2001; 122:633-40. [PMID: 11444616 DOI: 10.1017/s0031182001007855] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
To dissociate the influence of host age from length of exposure on acquisition of filarial infection, we examined the development of microfilaraemia and anti-filarial IgG4 in all ages of a naive population that became suddenly exposed to Brugia malayi as a result of transmigration. Responses in 247 transmigrants, who had settled for periods of several months up to 6 years in their new homesteads, were compared with those of 133 life-long residents. As shown in earlier studies, anti-filarial IgG4 increased with age in the indigenous populations, whose age is equivalent to length of exposure. However, by examining transmigrants, it became clear that development of specific IgG4 was influenced by age, since levels of this antibody were consistently higher in transmigrant adults than in transmigrant children, despite an equal length of exposure to filarial infection. Examining microfilaraemia, it was confirmed that infection establishes more rapidly in adults than in children.
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Affiliation(s)
- A J Terhell
- Department of Parasitology, Leiden University Medical Centre, The Netherlands
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Bogers J, Moreels T, De Man J, Vrolix G, Jacobs W, Pelckmans P, van Marck E. Schistosoma mansoni infection causing diffuse enteric inflammation and damage of the enteric nervous system in the mouse small intestine. Neurogastroenterol Motil 2000; 12:431-40. [PMID: 11012943 DOI: 10.1046/j.1365-2982.2000.00219.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Schistosomiasis mansoni is a major health problem, mainly occurring in developing countries. A large proportion of infected individuals suffers from motility-related gastrointestinal problems. In the present study, the diffuse inflammatory response in the small bowel wall, as compared to the egg-induced granulomatous inflammation, was investigated. For this purpose, OF1 mice infected with Schistosoma mansoni 8-16 weeks prior to the experiment, and uninfected control mice were studied. The ileum showed both a diffuse mucosal inflammation as well as a granulomatous reaction. The diffuse mucosal inflammation caused an increase in the thickness of the mucosa, with blunting of the villi. A significant, transient increase of thickness of the muscularis propria after 12 weeks of infection was noted. There was an infection-related mast cell infiltrate in the muscularis propria, consisting of formalin fixation-insensitive connective tissue mast cells. Ganglionitis of the myenteric plexus was noted. Rarely, ganglia of the myenteric plexus contained apoptotic cells. A general pharmacological set of experiments showed a significant increase in intestinal contractility, both to exogenously administered, as well as to endogenously released neurotransmitters. Our results demonstrate that S. mansoni infection in the mouse ileum leads to diffuse specific enteric inflammation that is associated with an enhanced response to contractile agents.
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Affiliation(s)
- J Bogers
- Laboratory of Pathology, University of Antwerp (UIA), Universiteitsplein 1, B-2610 Antwerp (Wilrijk), Belgium
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Corrêa-Oliveira R, Caldas IR, Gazzinelli G. Natural versus drug-induced resistance in Schistosoma mansoni infection. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:397-9. [PMID: 10951600 DOI: 10.1016/s0169-4758(00)01740-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Rodrigo Corrêa-Oliveira, Iramaya Rodrigues Caldas and Giovanni Gazzinelli here focus on the immune response of individuals with natural resistance to schistosomiasis, which differs significantly from that of post-treatment resistant and infected individuals. They suggest that the activation of T helper type 1 (Th1) and Th2 cells is needed for the induction of natural resistance against Schistosoma mansoni infection.
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Affiliation(s)
- R Corrêa-Oliveira
- Laboratório de Imunologia Celular e Molecular, Centro de Pesquisas René Rachou - FIOCRUZ, Av. Augusto de Lima 1715, Belo Horizonte, MG, 30190-002, Brazil.
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de Clercq D, Vercruysse J, Sène M, Seck I, Sall CS, Ly A, Southgate VR. The effects of irrigated agriculture on the transmission of urinary schistosomiasis in the Middle and Upper Valleys of the Senegal River basin. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2000; 94:581-90. [PMID: 11064760 DOI: 10.1080/00034983.2000.11813581] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The importance of the increase in irrigated land on the perimeters of the Middle and Upper Valleys of the Senegal River basin, on the prevalence and intensity of urinary schistosomiasis, was investigated. Surveys were conducted, in May-June 1997, to determine the prevalence and intensity of Schistosoma haematobium infection among 1445 children aged 7-14 years: 1011 in 10 villages near Matam, and 434 in four villages near Bakel. Macrohaematuria was present in seven of the study villages (four near Matan and three near Bakel), whereas microhaematuria was present in all the villages, with prevalences of 10%-73%. A second survey, conducted, in June 1999, on 755 children from nine of the study villages near Matam, demonstrated significant increases in the prevalences of both micro- and macro-haematuria in three of the villages, all of which were adjacent to the Senegal River and practising irrigated agriculture. None of the other study villages re-surveyed was irrigating any of its agricultural land. A longitudinal survey was also carried out, between May 1997 and November 1998, on about 10% of the population (2272 subjects) of Nguidjilone, north of Matam; selective treatment with praziquantel (40 mg/kg) was given in May 1997, and mass treatment in May 1998. The data analysed were those relating to the 125 individuals who provided samples at each survey. Very severe infections (> 1000 eggs/10 ml urine) were seen in five subjects in May 1997. One year later (i.e. 1 year after the selective treatment), the prevalence of urinary schistosomiasis had increased in every age-group. Although prevalence had decreased slightly by November 1998 (6 months after the mass treatment), the intensity of the infections seen had increased in every age-group. At the end of the dry season (May-June 1997), Bulinus truncalus infected with schistosome cercariae were recovered from the Senegal River. However, immediately after the next rainy season (November 1997), no snails were found at any collection site on the river.
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49
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Hagan P, Doenhoff MJ, Wilson RA, Al-Sherbiny M, Bergquist R. Schistosomiasis vaccines: a response to a devils' advocate's view. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:322-3. [PMID: 10900475 DOI: 10.1016/s0169-4758(00)01711-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- P Hagan
- Division of Infection and Immunity, IBLS, University of Glasgow, UK.
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50
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Drug resistance in human helminths: current situation and lessons from livestock. Clin Microbiol Rev 2000. [PMID: 10755998 DOI: 10.1128/cmr.13.2.207-222.2000] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this review the available reports on drug resistance in human helminths, particularly hookworms and schistosomes, are critically analyzed. The experiences with helminths of livestock are then reviewed, in particular the factors contributing to the development of anthelmintic resistance, the mechanisms and genetics of resistance to various anthelmintic classes, and the methods available for detection. These experiences appear to be worryingly similar and relevant to the potential development of drug resistance in human helminths. Recommendations to reduce its risks are suggested.
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