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Nyangiri OA, Mulindwa J, Namulondo J, Kitibwa A, Nassuuna J, Elliott A, Kimuda MP, Boobo A, Nerima B, Adriko M, Dunton NJ, Madhan GK, Kristiansen M, Casacuberta-Partal M, Noyes H, Matovu E. Variants of IL6, IL10, FCN2, RNASE3, IL12B and IL17B loci are associated with Schistosoma mansoni worm burden in the Albert Nile region of Uganda. PLoS Negl Trop Dis 2023; 17:e0011796. [PMID: 38033168 PMCID: PMC10715658 DOI: 10.1371/journal.pntd.0011796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 12/12/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Individuals genetically susceptible to high schistosomiasis worm burden may contribute disproportionately to transmission and could be prioritized for control. Identifying genes involved may guide development of therapy. METHODOLOGY/PRINCIPAL FINDINGS A cohort of 606 children aged 10-15 years were recruited in the Albert Nile region of Uganda and assessed for Schistosoma mansoni worm burden using the Up-Converting Particle Lateral Flow (UCP-LF) test detecting circulating anodic antigen (CAA), point-of-care Circulating Cathodic Antigen (POC-CCA) and Kato-Katz tests. Whole genome genotyping was conducted on 326 children comprising the top and bottom 25% of worm burden. Linear models were fitted to identify variants associated with worm burden in preselected candidate genes. Expression quantitative trait locus (eQTL) analysis was conducted for candidate genes with UCP-LF worm burden included as a covariate. Single Nucleotide Polymorphism loci associated with UCP-LF CAA included IL6 rs2066992 (OR = 0.43, p = 0.0006) and rs7793163 (OR = 2.0, p = 0.0007); IL21 SNP kgp513476 (OR 1.79, p = 0.0025) and IL17B SNP kgp708159 (OR = 0.35, p = 0.0028). A haplotype in the IL10 locus was associated with lower worm burden (OR = 0.53, p = 0.015) and overlapped SNPs rs1800896, rs1800871 and rs1800872. Significant haplotypes (p<0.05, overlapping significant SNP) associated with worm burden were observed in IL6 and the Th17 pathway IL12B and IL17B genes. There were significant eQTL in the IL6, IL5, IL21, IL25 and IFNG regions. CONCLUSIONS Variants associated with S. mansoni worm burden were in IL6, FCN2, RNASE3, IL10, IL12B and IL17B gene loci. However only eQTL associations remained significant after Bonferroni correction. In summary, immune balance, pathogen recognition and Th17 pathways may play a role in modulating Schistosoma worm burden. Individuals carrying risk variants may be targeted first in allocation of control efforts to reduce the burden of schistosomiasis in the community.
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Affiliation(s)
- Oscar Asanya Nyangiri
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Julius Mulindwa
- Department of Biochemistry and Sports Sciences, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Joyce Namulondo
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Anna Kitibwa
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Jacent Nassuuna
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Alison Elliott
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene & Tropical Medicine Uganda Research Unit, Entebbe, Uganda
| | - Magambo Phillip Kimuda
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Alex Boobo
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Barbara Nerima
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Moses Adriko
- Vector Borne & NTD Control Division, Ministry of Health, Uganda
| | - Nathan J. Dunton
- UCL Genomics core facility, University College London, London, United Kingdom
| | | | - Mark Kristiansen
- UCL Genomics core facility, University College London, London, United Kingdom
| | | | - Harry Noyes
- Centre for Genomic Research, University of Liverpool, Liverpool, United Kingdom
| | - Enock Matovu
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
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2
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Onkanga IO, Sang H, Hamilton R, Ondigo BN, Jaoko W, Odiere MR, Ganley-Leal L. CD193
(
CCR3
) expression by B cells correlates with reduced
IgE
production in paediatric schistosomiasis. Parasite Immunol 2023; 45:e12979. [PMID: 36971331 DOI: 10.1111/pim.12979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/21/2023] [Accepted: 03/15/2023] [Indexed: 03/29/2023]
Abstract
We demonstrate that CD193, the eotaxin receptor, is highly expressed on circulating B cells in paediatric schistosomiasis mansoni. CD193 plays a role in directing granulocytes into sites of allergic-like inflammation in the mucosa, but little is known about its functional significance on human B cells. We sought to characterize CD193 expression and its relationship with S. mansoni infection. We found that CD193+ B cells increased with the intensity of schistosome infection. In addition, a significant negative association was observed between CD193 expression by B cells and IgE production. Decreased IgE levels are generally associated with susceptibility to re-infection. B cell stimulation with eotaxin-1 increased CD193 levels whereas IL-4 led to a reduction. This was supported by plasma levels of eotaxin-1 correlating with CD193 levels on B cells and other cells. In contrast, CD193 expression was induced on naive B cells with a combination of IL-10 and schistosome antigens. Whereas T cells had a modest increase in CD193 expression, only B cell CD193 appeared functionally chemotactic to eotaxin-1. Thus, CD193+ B cells, which co-express CXCR5, may be enroute to sites with allergic-like inflammation, such as gastrointestinal follicles, or even to Th2 granulomas, which develop around parasite eggs. Overall, our results suggest that schistosome infection may promote CD193 expression and suppress IgE via IL-10 and other undefined mechanisms related to B cell trafficking. This study adds to our understanding of why young children may have poor immunity. Nonetheless, praziquantel treatment was shown to reduce percentages of circulating CD193+ B cells lending hope for future vaccine efforts.
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Affiliation(s)
- I O Onkanga
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
- KAVI-Institute of Clinical Research, and Department of Medical Microbiology & Immunology, University of Nairobi, Nairobi, Kenya
| | - H Sang
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - R Hamilton
- Elegance Biotechnologies, LLC, Wayne, Pennsylvania, USA
| | - B N Ondigo
- Department of Biochemistry and Molecular Biology, Faculty of Science, Egerton University, Egerton, Kenya
| | - W Jaoko
- KAVI-Institute of Clinical Research, and Department of Medical Microbiology & Immunology, University of Nairobi, Nairobi, Kenya
| | - M R Odiere
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - L Ganley-Leal
- Elegance Biotechnologies, LLC, Wayne, Pennsylvania, USA
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3
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Maseko TSB, Masuku SKS, Dlamini SV, Fan CK. Prevalence and distribution of urinary schistosomiasis among senior primary school pupils of Siphofaneni area in the low veld of Eswatini: A cross-sectional study. Helminthologia 2023; 60:28-35. [PMID: 37305666 PMCID: PMC10251754 DOI: 10.2478/helm-2023-0005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 02/21/2023] [Indexed: 06/13/2023] Open
Abstract
A cross-sectional survey of Schistosoma haematobium prevalence was conducted among senior primary school pupils of Siphofaneni area, Eswatini. This area is devoid of potable water, with a newly constructed Lubovane dam and an LUSIP irrigation scheme. The objective of the study was to investigate the distribution of urinary schistosomiasis among Siphofaneni senior primary school pupils. Using simple random sampling, 200 partcipants were enroled from four of six schools in the area. Ten millimetres (10 ml) of urine samples were obtained from each participant and examined for S. haematobium eggs. The intensity of the infection was estimated by calculating the total number of S. haematobium eggs present in 10 ml urine. Out of 200 participants, 45% (n = 91) were males, and 55% (n = 109) were females. The mean age for participants was 13 years, and almost half (47%, n = 94) were in Grade 5. Overall, the prevalence of S. haematobium infection was 16% (32/200). More than half (59%, 19/32) of the Schistosomiasis cases were from females. Positive and significant associations were observed between the number of eggs (χ2=170.9) and the presence of red blood cells (χ2=49.2) at p = 0.001. In conclusion, the prevalence of Schistosomiasis is high among pupils enrolled in Siphofaneni area primary schools that needs comprehensive treatment and education to prevent from S. haematobium infection.
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Affiliation(s)
| | | | - S. V. Dlamini
- Department of Environmental Health Sciences, Faculty of Health Sciences, University of Eswatini
| | - C.-K. Fan
- Department of Molecular Parasitology and Tropical Diseases, School of Medicine, College of Medicine, Taipei Medical University, 250, Wu-Xing Street, Taipei, Taiwan
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4
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Expression of CD117 (c-Kit) on Circulating B Cells in Pediatric Schistosomiasis. Infect Immun 2022; 90:e0016022. [PMID: 35862720 PMCID: PMC9387214 DOI: 10.1128/iai.00160-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Few B cells express CD27, the primary marker for memory B cells, in pediatric schistosomiasis, suggesting B cell malfunction. This study further demonstrates unexpected high expression of CD117 on circulating B cells in children highly exposed to Schistosoma mansoni infectious larvae. CD117 is expressed by immature or lymphoma B cells, but not by mature, circulating cells. We therefore sought to define the significance of CD117 on blood B cells. We found that CD117-positive (CD117+) B cells increased with the intensity of schistosome infection. In addition, CD117 expression was reduced on CD23+ B cells previously shown to correlate with resistance to infection. Stimulation with a panel of cytokines demonstrated that CD117 levels were upregulated in response to a combination of interleukin 4 (IL-4) and stem cell factor (SCF), the ligand for CD117, whereas IL-2 led to a reduction. In addition, stimulation with SCF generally reduced B cell activation levels. Upon further investigation, it was established that multiple circulating cells expressed increased levels of CD117, including monocytes, neutrophils, and eosinophils, and expression levels correlated with that of B cells. Finally, we identified a population of large circulating cells with features of reticulocytes. Overall, our results suggest that hyperexposure to intravascular parasitic worms elicits immature cells from the bone marrow. Levels of SCF were shown to reduce as children began to transition through puberty. The study results pose an explanation for the inability of children to develop significant immunity to infection until after puberty.
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5
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Sang HC, Mwinzi PNM, Odiere MR, Onkanga I, Rawago F, Pillay P, Kjetland EF. Absence of lower genital tract lesions among women of reproductive age infected with Schistosoma mansoni: A cross-sectional study using a colposcope in Western Kenya. PLoS Negl Trop Dis 2022; 16:e0010473. [PMID: 35802746 PMCID: PMC9299320 DOI: 10.1371/journal.pntd.0010473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/20/2022] [Accepted: 05/06/2022] [Indexed: 11/18/2022] Open
Abstract
Background
Female genital schistosomiasis (FGS) constitutes four different lesions known to be caused by Schistosoma haematobium ova deposited in the genital tract. Schistosoma mansoni ova may also be found in the genital tract. However, it is not known if S. mansoni causes lower genital tract lesions characteristic of FGS.
Methodology
This study was conducted in 8 villages along the shores of Lake Victoria, western Kenya. Stool and urine samples, collected from women of reproductive age on three consecutive days, were analysed for S. mansoni and S. haematobium infection. S. mansoni positive and S. haematobium negative willing participants, aged 18–50 years were invited to answer a questionnaire (demographics, symptoms), undergo a gynaecological examination and cytology specimen collection by an FGS expert.
Principal findings
Gynaecologic investigations were conducted in 147 S. mansoni-positive women who had a mean infection intensity of 253.3 epg (95% CI: 194.8–311.9 epg). Nearly 90% of them used Lake Victoria as their main water source. None were found to have cervicovaginal grainy sandy patches or rubbery papules. Homogenous yellow patches were found in 12/147 (8.2%) women. Women with homogenous yellow patches were significantly older (47 years) than the rest (34 years, p = 0.001). No association was found between intensity of S. mansoni infection and homogenous yellow patches (p = 0.70) or abnormal blood vessels (p = 0.14). S. mansoni infection intensity was not associated with genital itch, bloody or malodorous vaginal discharge.
Conclusion
S. mansoni infection was neither associated with lower genital tract lesions nor symptoms typically found in women with FGS.
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Affiliation(s)
- Huldah C. Sang
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Pauline N. M. Mwinzi
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Maurice R. Odiere
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Isaac Onkanga
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Fredrick Rawago
- Neglected Tropical Diseases Unit, Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Pavitra Pillay
- Department of Biomedical and Clinical Technology, Faculty of Health Sciences, Durban University of Technology, Durban, South Africa
| | - Eyrun Floerecke Kjetland
- Norwegian Centre for Imported and Tropical Diseases, Department of Infectious Diseases Ullevaal, Oslo University Hospital, Oslo, Norway
- Discipline of Public Health, Nelson Mandela School of Medicine, University of KwaZulu-Natal, Durban, South Africa
- * E-mail:
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6
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Hambrook JR, Hanington PC. Immune Evasion Strategies of Schistosomes. Front Immunol 2021; 11:624178. [PMID: 33613562 PMCID: PMC7889519 DOI: 10.3389/fimmu.2020.624178] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/22/2020] [Indexed: 11/13/2022] Open
Abstract
Human schistosomes combat the unique immune systems of two vastly different hosts during their indirect life cycles. In gastropod molluscs, they face a potent innate immune response composed of variable immune recognition molecules and highly phagocytic hemocytes. In humans, a wide variety of innate and adaptive immune processes exist in proximity to these parasites throughout their lifespan. To survive and thrive as the second most common parasitic disease in humans, schistosomes have evolved many techniques to avoid and combat these targeted host responses. Among these techniques are molecular mimicry of host antigens, the utilization of an immune resistant outer tegument, the secretion of several potent proteases, and targeted release of specific immunomodulatory factors affecting immune cell functions. This review seeks to describe these key immune evasion mechanisms, among others, which schistosomes use to survive in both of their hosts. After diving into foundational observational studies of the processes mediating the establishment of schistosome infections, more recent transcriptomic and proteomic studies revealing crucial components of the host/parasite molecular interface are discussed. In order to combat this debilitating and lethal disease, a comprehensive understanding of schistosome immune evasion strategies is necessary for the development of novel therapeutics and treatment plans, necessitating the discussion of the numerous ways in which these parasitic flatworms overcome the immune responses of both hosts.
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Affiliation(s)
- Jacob R Hambrook
- School of Public Health, University of Alberta, Edmonton, AB, Canada
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7
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Immune-neuroendocrine and metabolic disorders in human and experimental T. cruzi infection: New clues for understanding Chagas disease pathology. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165642. [PMID: 31866417 DOI: 10.1016/j.bbadis.2019.165642] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 12/13/2019] [Indexed: 12/12/2022]
Abstract
Studies in mice undergoing acute Trypanosoma cruzi infection and patients with Chagas disease, led to identify several immune-neuroendocrine disturbances and metabolic disorders. Here, we review relevant findings concerning such abnormalities and discuss their possible influence on disease physiopathology.
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8
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Murenjekwa W, Makasi R, Ntozini R, Chasekwa B, Mutasa K, Moulton LH, Tielsch JM, Humphrey JH, Smith LE, Prendergast AJ, Bourke CD. Determinants of Urogenital Schistosomiasis Among Pregnant Women and its Association With Pregnancy Outcomes, Neonatal Deaths, and Child Growth. J Infect Dis 2019; 223:1433-1444. [PMID: 31832636 PMCID: PMC8064048 DOI: 10.1093/infdis/jiz664] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 12/11/2019] [Indexed: 11/28/2022] Open
Abstract
Background Schistosoma haematobium is a parasitic helminth that causes urogenital pathology. The impact of urogenital schistosomiasis during pregnancy on birth outcomes and child growth is poorly understood. Methods Risk factors for urogenital schistosomiasis were characterized among 4437 pregnant women enrolled in a cluster-randomized community-based trial in rural Zimbabwe. Infection was defined via urine microscopy (≥1 S. haematobium egg) and urinalysis (hematuria). Associations between infection and pregnancy outcomes were assessed in case-control analyses using conditional logistic regression. The association of maternal infection with birthweight and length-for-age Z scores (LAZ) at 1 and 18 months of age were assessed using generalized estimating equations. Results Urogenital schistosomiasis (egg positive and/or hematuria positive) was detected in 26.8% of pregnant women. Risk factors significantly associated with infection were maternal age, education, marital status, and religion; household drinking water source and latrine; study region; and season. Urogenital schistosomiasis was not significantly associated with adverse pregnancy outcomes (miscarriage, stillbirth, preterm, and small-for-gestational age), birthweight, neonatal death, or LAZ. Conclusions Including pregnant women in antihelminthic treatment programs would benefit a large number of women in rural Zimbabwe. However, clearance of the low-intensity infections that predominate in this context is unlikely to have additive benefits for pregnancy outcomes or child growth. Clinical Trials Registration NCT01824940.
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Affiliation(s)
| | - Rachel Makasi
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
| | - Robert Ntozini
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
| | - Bernard Chasekwa
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
| | - Kuda Mutasa
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
| | - Lawrence H Moulton
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - James M Tielsch
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Jean H Humphrey
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe.,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Laura E Smith
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe.,Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York, USA
| | - Andrew J Prendergast
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe.,Blizard Institute, Queen Mary University of London, London, UK
| | - Claire D Bourke
- Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe.,Blizard Institute, Queen Mary University of London, London, UK
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9
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Mazigo HD, Kirway L, Ambrose EA. Prevalence and intensity of Schistosoma mansoni infection in pediatric populations on antiretroviral therapy in north-western Tanzania: a cross-sectional study. BMJ Open 2019; 9:e029749. [PMID: 31345980 PMCID: PMC6661605 DOI: 10.1136/bmjopen-2019-029749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND In areas where HIV and intestinal schistosomiasis are highly endemic, co-infections of the two diseases in a single human host are frequent. Evidence in adult populations indicates that HIV and intestinal schistosomiasis are associated with negative health impacts. However, the topic of HIV and schistosomiasis in paediatric populations has received little attention. The present study determined the prevalence and intensity of Schistosoma mansoni infection in a paediatric population on antiretroviral therapy (ART) in north-western Tanzania. DESIGN, SETTINGS AND PARTICIPANTS A cross-sectional study was conducted among HIV-infected children aged 1-16 years on ART attending a Care and Treatment Clinic at Ukerewe Designated District Hospital, north-western Tanzania. MAIN OUTCOME MEASURES Single stool and urine samples were collected and screened for S. mansoni eggs and circulating cathodic antigen (CCA), using the Kato-Katz (KK) technique and point-of-care CCA (POC-CCA) rapid urine test, respectively. RESULTS A total of 134 children with a median age of 10 years (IQR 7-12 years) participated in the study. Of these, 44.8% (60/134) and 55.2% (74/134) were female and male, respectively. The overall prevalence of S. mansoni based on the KK technique and POC-CCA rapid test were 10.7% (95% CI 5.9% to 18.4%) and 33.8% (95% CI 26.2% to 42.4%), respectively. The overall geometrical mean eggs per gram of faeces was 293.9 GM-epg (95% CI 123.3 to 700.9). A small proportion of the children had moderate (4.9%, 5/103) and heavy (3.8%, 4/103) intensity of infection. CONCLUSION Paediatric populations on ART are co-infected with S. mansoni infection. Screening and treatment of intestinal schistosomiasis at initiation of ART is recommended to reduce the risk of developing hepatosplenic disease, schistosomiasis-related immune reconstitution inflammatory syndrome and the possible adverse effect of schistosomiasis on outcome of ART.
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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, Mwanza, United Republic of Tanzania
| | - Laurence Kirway
- Department of Pediatricts and Child Health, Bugando Medical Centre, Mwanza, United Republic of Tanzania
| | - Emmanuela Ausebio Ambrose
- Department of Biomedical Sciences, Bishop Nicodemus Hhando College of Health Scineces, Manyara, United Republic of Tanzania
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10
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Ndombi EM, Abudho B, Kittur N, Carter JM, Korir H, Riner DK, Ochanda H, Lee YM, Secor WE, Karanja DM, Colley DG. Effect of four rounds of annual school-wide mass praziquantel treatment for schistosoma mansoni control on schistosome-specific immune responses. Parasite Immunol 2018; 40:e12530. [PMID: 29604074 PMCID: PMC6001474 DOI: 10.1111/pim.12530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/22/2018] [Indexed: 11/27/2022]
Abstract
This study evaluated potential changes in antischistosome immune responses in children from schools that received 4 rounds of annual mass drug administration (MDA) of praziquantel (PZQ). In a repeated cross‐sectional study design, 210 schistosome egg‐positive children were recruited at baseline from schools in western Kenya (baseline group). Another 251 children of the same age range were recruited from the same schools and diagnosed with schistosome infection by microscopy (post‐MDA group). In‐vitro schistosome‐specific cytokines and plasma antibody levels were measured by ELISA and compared between the 2 groups of children. Schistosome soluble egg antigen (SEA) and soluble worm antigen preparation (SWAP) stimulated higher IL‐5 production by egg‐negative children in the post‐MDA group compared to the baseline group. Similarly, anti‐SEA IgE levels were higher in egg‐negative children in the post‐MDA group compared to the baseline group. Anti‐SEA and anti‐SWAP IgG4 levels were lower in egg‐negative children in the post‐MDA group compared to baseline. This resulted in higher anti‐SEA IgE/IgG4 ratios for children in the post‐MDA group compared to baseline. These post‐MDA immunological changes are compatible with the current paradigm that treatment shifts immune responses to higher antischistosome IgE:IgG4 ratios in parallel with a potential increase in resistance to reinfection.
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Affiliation(s)
- E M Ndombi
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.,School of Biological Sciences, University of Nairobi, Nairobi, Kenya.,Department of Pathology, Kenyatta University, Nairobi, Kenya
| | - B Abudho
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya.,Department of Biomedical Sciences, Maseno University, Maseno, Kenya
| | - N Kittur
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - J M Carter
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - H Korir
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - D K Riner
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - H Ochanda
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Y-M Lee
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - W E Secor
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - D M Karanja
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - D G Colley
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA.,Department of Microbiology, University of Georgia, Athens, GA, USA
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11
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Schistosome vaccines: problems, pitfalls and prospects. Emerg Top Life Sci 2017; 1:641-650. [PMID: 33525844 DOI: 10.1042/etls20170094] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 12/14/2022]
Abstract
Human schistosomiasis caused by parasitic flatworms of the genus Schistosoma remains an important public health problem in spite of concerted efforts at control. An effective vaccine would be a useful addition to control strategies that currently rely on chemotherapy, but such a product is not imminent. In this review, likely causes for the lack of progress are first considered. These include the strategies used by worms to evade the immune response, concepts that have misdirected the field, an emphasis on internal antigens, and the use of the laboratory mouse for vaccine testing. On a positive note, recent investigations on self-cure by the rhesus macaque offer the most promising context for vaccine development. The identification of proteins at the parasite-host interface, especially those of the esophageal glands involved in blood processing, has provided an entirely new category of vaccine candidates that merit evaluation.
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12
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Tchuem Tchuenté LA, Rollinson D, Stothard JR, Molyneux D. Moving from control to elimination of schistosomiasis in sub-Saharan Africa: time to change and adapt strategies. Infect Dis Poverty 2017; 6:42. [PMID: 28219412 PMCID: PMC5319063 DOI: 10.1186/s40249-017-0256-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 02/08/2017] [Indexed: 11/17/2022] Open
Abstract
Schistosomiasis is a water borne parasitic disease of global importance and with ongoing control the disease endemic landscape is changing. In sub-Saharan Africa, for example, the landscape is becoming ever more heterogeneous as there are several species of Schistosoma that respond in different ways to ongoing preventive chemotherapy and the inter-sectoral interventions currently applied. The major focus of preventive chemotherapy is delivery of praziquantel by mass drug administration to those shown to be, or presumed to be, at-risk of infection and disease. In some countries, regional progress may be uneven but in certain locations there are very real prospects to transition from control into interruption of transmission, and ultimately elimination. To manage this transition requires reconsideration of some of the currently deployed diagnostic tools used in surveillance and downward realignment of existing prevalence thresholds to trigger mass treatment. A key challenge will be maintaining and if possible, expanding the current donation of praziquantel to currently overlooked groups, then judging when appropriate to move from mass drug administration to selective treatment. In so doing, this will ensure the health system is adapted, primed and shown to be cost-effective to respond to these changing disease dynamics as we move forward to 2020 targets and beyond.
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Affiliation(s)
- Louis-Albert Tchuem Tchuenté
- National Programme for the Control of Schistosomiasis and STH, Ministry of Public Health, Yaoundé, Cameroon. .,Centre for Schistosomiasis and Parasitology, University of Yaoundé I, Yaoundé, Cameroon.
| | - David Rollinson
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, UK
| | - J Russell Stothard
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - David Molyneux
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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13
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Deol A, Webster JP, Walker M, Basáñez MG, Hollingsworth TD, Fleming FM, Montresor A, French MD. Development and evaluation of a Markov model to predict changes in schistosomiasis prevalence in response to praziquantel treatment: a case study of Schistosoma mansoni in Uganda and Mali. Parasit Vectors 2016; 9:543. [PMID: 27729063 PMCID: PMC5059905 DOI: 10.1186/s13071-016-1824-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 10/01/2016] [Indexed: 11/23/2022] Open
Abstract
Background Understanding whether schistosomiasis control programmes are on course to control morbidity and potentially switch towards elimination interventions would benefit from user-friendly quantitative tools that facilitate analysis of progress and highlight areas not responding to treatment. This study aimed to develop and evaluate such a tool using large datasets collected during Schistosomiasis Control Initiative-supported control programmes. Methods A discrete-time Markov model was developed using transition probability matrices parameterized with control programme longitudinal data on Schistosoma mansoni obtained from Uganda and Mali. Four matrix variants (A-D) were used to compare different data types for parameterization: A-C from Uganda and D from Mali. Matrix A used data at baseline and year 1 of the control programme; B used year 1 and year 2; C used baseline and year 1 from selected districts, and D used baseline and year 1 Mali data. Model predictions were tested against 3 subsets of the Uganda dataset: dataset 1, the full 4-year longitudinal cohort; dataset 2, from districts not used to parameterize matrix C; dataset 3, cross-sectional data, and dataset 4, from Mali as an independent dataset. Results The model parameterized using matrices A, B and D predicted similar infection dynamics (overall and when stratified by infection intensity). Matrices A-D successfully predicted prevalence in each follow-up year for low and high intensity categories in dataset 1 followed by dataset 2. Matrices A, B and D yielded similar and close matches to dataset 1 with marginal discrepancies when comparing model outputs against datasets 2 and 3. Matrix C produced more variable results, correctly estimating fewer data points. Conclusion Model outputs closely matched observed values and were a useful predictor of the infection dynamics of S. mansoni when using longitudinal and cross-sectional data from Uganda. This also held when the model was tested with data from Mali. This was most apparent when modelling overall infection and in low and high infection intensity areas. Our results indicate the applicability of this Markov model approach as countries aim at reaching their control targets and potentially move towards the elimination of schistosomiasis. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1824-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Arminder Deol
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK.
| | - Joanne P Webster
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK.,Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases, Royal Veterinary College, University of London, Herts, London, AL9 7TA, UK.,London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus), Imperial College London, London, W2 1PG, UK
| | | | - Fiona M Fleming
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK
| | - Antonio Montresor
- Neglected Tropical Disease Department, World Health Organization, Avenue Appia, 20, Geneva, Switzerland
| | - Michael D French
- Schistosomiasis Control Initiative, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's campus) Imperial College London, London, W2 1PG, UK
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14
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Richardson ST, Franklin AL, Rome ES, Simms-Cendan JS. Global Health: Urogenital Schistosomiasis in the Adolescent Girl. J Pediatr Adolesc Gynecol 2016; 29:326-32. [PMID: 26173381 DOI: 10.1016/j.jpag.2014.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/11/2014] [Accepted: 07/16/2014] [Indexed: 11/28/2022]
Abstract
Urogenital schistosomiasis affects millions of women in sub-Saharan Africa. Infection by the causative organism, Schistosoma hematobium, commonly occurs during childhood and adolescence and can lead to anemia from hematuria, inflammation on the cervix which can increase risk of HIV transmission, and pelvic infection leading to infertility. Fortunately treatment is not costly, but early diagnosis is important to reduce long-term morbidity. Our objective is to review the epidemiology, pathophysiology, and diagnosis of urogenital schistosomiasis as well as treatment to improve the reproductive health of girls where this infection is endemic.
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Affiliation(s)
- Sharise T Richardson
- Department of Obstetrics & Gynecology, University of Miami, Miller School of Medicine, Miami, FL
| | - Ashley L Franklin
- Department of Clinical Sciences, University of Central Florida College of Medicine, Orlando, FL
| | - Ellen S Rome
- Cleveland Clinic Lerner College of Medicine, Center for Adolescent Medicine, Cleveland, OH
| | - Judith S Simms-Cendan
- Department of Clinical Sciences, University of Central Florida College of Medicine, Orlando, FL.
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15
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Chronic Infections Leading to Squamous Cell Carcinoma From Chronic Inflammation. INFECTIOUS DISEASES IN CLINICAL PRACTICE 2016. [DOI: 10.1097/ipc.0000000000000349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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de Assis RR, Ludolf F, Nakajima R, Jasinskas A, Oliveira GC, Felgner PL, Gaze ST, Loukas A, LoVerde PT, Bethony JM, Correa-Oliveira R, Calzavara-Silva CE. A next-generation proteome array for Schistosoma mansoni. Int J Parasitol 2016; 46:411-5. [PMID: 27131510 DOI: 10.1016/j.ijpara.2016.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 04/09/2016] [Accepted: 04/09/2016] [Indexed: 02/06/2023]
Abstract
A proteome microarray consisting of 992 Schistosoma mansoni proteins was produced and screened with sera to determine antibody signatures indicative of the clinical stages of schistosomiasis and the identification of subunit vaccine candidates. Herein, we describe the methods used to derive the gene list for this array (representing approximately 10% of the predicted S. mansoni proteome). We also probed a pilot version of the microarray with sera from individuals either acutely or chronically infected with S. mansoni from endemic areas in Brazil and sera from individuals resident outside the endemic area (USA) to determine if the array is functional and informative.
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Affiliation(s)
- Rafael Ramiro de Assis
- Laboratório de Imunologia Celular e Molecular, Instituto Rene Rachou, FIOCRUZ, Belo Horizonte, MG, Brazil; Protein Microarray Laboratory, Division of Infectious Disease, School of Medicine, University of California, Irvine, CA, USA
| | - Fernanda Ludolf
- Infectologia e Medicina Tropical, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Rie Nakajima
- Protein Microarray Laboratory, Division of Infectious Disease, School of Medicine, University of California, Irvine, CA, USA
| | - Al Jasinskas
- Protein Microarray Laboratory, Division of Infectious Disease, School of Medicine, University of California, Irvine, CA, USA
| | | | - Philip L Felgner
- Protein Microarray Laboratory, Division of Infectious Disease, School of Medicine, University of California, Irvine, CA, USA
| | - Soraya T Gaze
- Laboratório de Imunologia Celular e Molecular, Instituto Rene Rachou, FIOCRUZ, Belo Horizonte, MG, Brazil
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health & Medicine, James Cook University, Cairns, QLD, Australia
| | - Philip T LoVerde
- Departments of Biochemistry and Pathology, School of Medicine, University of Texas Health Science Center, 7703 Floyd Curl Dr., San Antonio, TX 78229, USA
| | - Jeffrey M Bethony
- Laboratório de Imunologia Celular e Molecular, Instituto Rene Rachou, FIOCRUZ, Belo Horizonte, MG, Brazil; Department of Microbiology, Immunology, and Tropical Medicine, School of Medicine and Health Science, The George Washington University, Washington, DC, USA.
| | - Rodrigo Correa-Oliveira
- Laboratório de Imunologia Celular e Molecular, Instituto Rene Rachou, FIOCRUZ, Belo Horizonte, MG, Brazil
| | - Carlos E Calzavara-Silva
- Laboratório de Imunologia Celular e Molecular, Instituto Rene Rachou, FIOCRUZ, Belo Horizonte, MG, Brazil; Protein Microarray Laboratory, Division of Infectious Disease, School of Medicine, University of California, Irvine, CA, USA
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17
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Ojurongbe O, Antony JS, Van Tong H, Meyer CG, Akindele AA, Sina-Agbaje OR, Kremsner PG, Velavan TP. Low MBL-associated serine protease 2 (MASP-2) levels correlate with urogenital schistosomiasis in Nigerian children. Trop Med Int Health 2015; 20:1311-9. [PMID: 26046446 DOI: 10.1111/tmi.12551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The human mannose-binding lectin (MBL) and ficolins (FCN) are involved in pathogen recognition in the first line of defence. They support activation of the complement lectin cascade in the presence of MBL-associated serine protease 2 (MASP-2), a protein that cleaves the C4 and C2 complement components. Recent studies found that distinct MBL2 and FCN2 promoter variants and their corresponding serum levels are associated with relative protection from urogenital schistosomiasis. METHODS We investigated the contribution of MASP-2 levels and MASP2 polymorphisms in a Nigerian study group, of 163 individuals infected with Schistosoma haematobium and 183 healthy subjects. RESULTS MASP-2 serum levels varied between younger children (≤12 years) and older children (>12 years) and adults (P = 0.0001). Younger children with a patent infection had significantly lower MASP-2 serum levels than uninfected children (P = 0.0074). Older children and adults (>12 years) with a current infection had higher serum MASP-2 levels than controls (P = 0.032). MBL serum levels correlated positively with MASP-2 serum levels (P = 0.01). MASP2 secretor haplotypes were associated with MASP-2 serum levels in healthy subjects. The heterozygous MASP2 p.P126L variant was associated with reduced serum MASP-2 levels (P = 0.01). CONCLUSIONS The findings indicate that higher MASP-2 serum levels are associated with relative protection from urogenital schistosomiasis in Nigerian children.
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Affiliation(s)
- Olusola Ojurongbe
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Ladoke Akintola University of Technology, Ogbomoso, Nigeria
| | - Justin S Antony
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Hoang Van Tong
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Christian G Meyer
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | | | | | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Thirumalaisamy P Velavan
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,Fondation Congolaise pour la Recherche Medicale, Brazzaville, Republic of Congo
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Grimes JET, Croll D, Harrison WE, Utzinger J, Freeman MC, Templeton MR. The roles of water, sanitation and hygiene in reducing schistosomiasis: a review. Parasit Vectors 2015; 8:156. [PMID: 25884172 PMCID: PMC4377019 DOI: 10.1186/s13071-015-0766-9] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/18/2015] [Indexed: 11/10/2022] Open
Abstract
Schistosomiasis is a disease caused by infection with blood flukes of the genus Schistosoma. Transmission of, and exposure to, the parasite result from faecal or urinary contamination of freshwater containing intermediate host snails, and dermal contact with the same water. The World Health Assembly resolution 65.21 from May 2012 urges member states to eliminate schistosomiasis through preventive chemotherapy (i.e. periodic large-scale administration of the antischistosomal drug praziquantel to school-aged children and other high-risk groups), provision of water, sanitation and hygiene (WASH) and snail control. However, control measures focus almost exclusively on preventive chemotherapy, while only few studies made an attempt to determine the impact of upgraded access to safe water, adequate sanitation and good hygiene on schistosome transmission. We recently completed a systematic review and meta-analysis pertaining to WASH and schistosomiasis and found that people with safe water and adequate sanitation have significantly lower odds of a Schistosoma infection. Importantly though, the transmission of schistosomiasis is deeply entrenched in social-ecological systems, and hence is governed by setting-specific cultural and environmental factors that determine human behaviour and snail populations. Here, we provide a comprehensive review of the literature, which explores the transmission routes of schistosomes, particularly focussing on how these might be disrupted with WASH-related technologies and human behaviour. Additionally, future research directions in this area are highlighted.
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Affiliation(s)
- Jack E T Grimes
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK.
| | - David Croll
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, , CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, , CH-4003, Basel, Switzerland.
| | - Wendy E Harrison
- Schistosomiasis Control Initiative, Imperial College London, London, SW7 2AZ, UK.
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, , CH-4002, Basel, Switzerland. .,University of Basel, P.O. Box, , CH-4003, Basel, Switzerland.
| | - Matthew C Freeman
- Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, 30322, USA.
| | - Michael R Templeton
- Department of Civil and Environmental Engineering, Imperial College London, London, SW7 2AZ, UK.
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19
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Mazigo HD, Dunne DW, Wilson S, Kinung'hi SM, Pinot de Moira A, Jones FM, Morona D, Nuwaha F. Co-infection with Schistosoma mansoni and Human Immunodeficiency Virus-1 (HIV-1) among residents of fishing villages of north-western Tanzania. Parasit Vectors 2014; 7:587. [PMID: 25511298 PMCID: PMC4271490 DOI: 10.1186/s13071-014-0587-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/02/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Co-infection with S. mansoni and Human Immunodeficiency Virus-1 (HIV-1) has been described in sub-Saharan Africa. However, few community-based studies have been conducted to assess the association between the two diseases. The present study examined whether the infection with HIV-1 is associated with an altered susceptibility to S. mansoni infection by comparing the prevalence and intensity of S. mansoni infection among those infected and not infected with HIV-1. Any influence of HIV-1 associated immunodeficiency on the intensity of S. mansoni infection was also investigated. METHODS A cross-sectional study was conducted among 1,785 randomly selected adults (aged 21-55 years) in fishing villages of north-western Tanzania. 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. Demographic information was collected by questionnaire. RESULTS Of the 1,785 individuals from whom complete data were obtained, 854 (47.85%, 95% CI; 40.46 - 56.57) were infected with S. mansoni and had a mean intensity of 183.21(95% CI; 165.61-202.70) eggs per gram of faeces (epg). A total of 125 individuals (6.29%, 95% CI 3.59-11.04) were infected with HIV-1 and only 40% (n=50) of them were co-infected with S. mansoni. No differences in prevalence of S. mansoni infection or intensities of infection, as estimated by egg count (epg), were observed between HIV-1 sero-positive individuals and HIV-1 negative individuals. In generalized regression models (adjusted for sex, age, occupation, residence and level of education), being infected with HIV-1 did not increase the risk (APR=1.01, 95%; 0.83-1.21, P=0.93) or intensity (AOR = 0.84, 95% CI; 0.56-1.25, P = 0.33) of S. mansoni infection. Among individuals co-infected with HIV-1 and S. mansoni infection, the intensity of infection (epg) was not associated (P = 0.21) or correlated (P = 0.13) with CD4(+) cell counts. CONCLUSION Our findings suggest that HIV-1 infection may not have a major effect on S. mansoni infection or on the excretion of eggs from the co-infected individuals. However, further studies are needed to understand the biological interaction between HIV-1 and S. mansoni in a large cohort of co-infected individuals.
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Affiliation(s)
- Humphrey D Mazigo
- Department of Medical Parasitology and Entomology, Weill 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 & Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1Q3 P, UK.
| | - David W Dunne
- Department of Pathology, Division of Microbiology & Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1Q3 P, UK.
| | - Shona Wilson
- Department of Pathology, Division of Microbiology & Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1Q3 P, UK.
| | - Safari M Kinung'hi
- National Institute for Medical Research, Mwanza Research Centre, P.O. Box 1462, Mwanza, Tanzania.
| | - Angela Pinot de Moira
- Department of Pathology, Division of Microbiology & Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1Q3 P, UK.
| | - Frances M Jones
- Department of Pathology, Division of Microbiology & Parasitology, Cambridge University, Tennis Court Road, Cambridge, CB2 1Q3 P, UK.
| | - Domenica Morona
- Department of Medical Parasitology and Entomology, Weill School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, 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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20
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Ndeffo Mbah ML, Gilbert JA, Galvani AP. Evaluating the potential impact of mass praziquantel administration for HIV prevention in Schistosoma haematobium high-risk communities. Epidemics 2014; 7:22-7. [PMID: 24928666 DOI: 10.1016/j.epidem.2014.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 10/18/2013] [Accepted: 04/03/2014] [Indexed: 10/25/2022] Open
Abstract
Genital infection with Schistosoma haematobium is prevalent in sub-Saharan Africa. Epidemiological studies have observed that genital schistosomiasis is associated with an increased odd of HIV infection among women. We used mathematical modeling to explore the potential impact of mass preventive chemotherapy against schistosomiasis on HIV transmission in three sub-Saharan Africa countries: Angola, Kenya, and Zambia. We developed a model of female genital schistosomiasis (FGS) and HIV transmission dynamics, fitting it to data of HIV and S. haematobium prevalences as well as co-infection. We simulated targeted mass drug administration (MDA) with praziquantel to school-age children and mass treatment of the entire community. We estimated that, in S. haematobium high-risk communities, targeted annual treatment of school-age children could reduce HIV prevalence by 20% (95% CI: 12-31%) in Angola, 16% (95% CI: 10-32%) in Kenya, and 6% (95% CI: 3-18%) in Zambia after the first 20 years of intervention; and would reduce HIV incidence by 15% (95% CI: 13-32%) in Angola, 22% (95% CI: 18-42%) in Kenya, and 9% (95% CI: 3-22%) in Zambia. Extending the intervention to adults could reduce HIV prevalence by an additional 2.2% (95% CI: 0.2-12.0%) in Angola, 1.8% (95% CI: 0.1-5.2%) in Kenya, and 0.3% (95% CI: 0.1-2.1%) in Zambia; and would reduce HIV incidence by an additional 1.8% (95% CI: 0.0-14.4%) in Angola, 6.1% (95% CI: 0.5-12.6%) in Kenya, and 0.8% (95% CI: 0.0-2.7%) in Zambia. We showed that the exacerbation of HIV transmission due to FGS and the probability of developing FGS as a result of childhood infection with S. haematobium, were the most important factors in determining the effectiveness of praziquantel MDA for reducing HIV transmission. Praziquantel MDA may be an innovative measure for reducing schistosomiasis and HIV transmission in sub-Saharan Africa, the effectiveness of which varies with HIV prevalence.
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Affiliation(s)
| | | | - Alison P Galvani
- School of Public Health, Yale University, New Haven, CT, USA; Center for Interdisciplinary Research on AIDS, Yale University, New Haven, CT, USA
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21
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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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22
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Brooker S, Bethony JM, Rodrigues LC, Alexander N, Geiger SM, Hotez PJ. Epidemiologic, immunologic and practical considerations in developing and evaluating a human hookworm vaccine. Expert Rev Vaccines 2014. [DOI: 10.1586/14760584.4.1.35] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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Lemaitre M, Watier L, Briand V, Garcia A, Le Hesran JY, Cot M. Coinfection with Plasmodium falciparum and Schistosoma haematobium: additional evidence of the protective effect of Schistosomiasis on malaria in Senegalese children. Am J Trop Med Hyg 2013; 90:329-34. [PMID: 24323515 DOI: 10.4269/ajtmh.12-0431] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Parasitic infections are associated with high morbidity and mortality in developing countries. Several studies focused on the influence of helminth infections on malaria but the nature of the biological interaction is under debate. Our objective was to undertake a study to explore the influence of the measure of excreted egg load caused by Schistosoma haematobium on Plasmodium falciparum parasite densities. Ten measures of malaria parasite density and two measures of schistosomiasis egg urinary excretion over a 2-year follow-up period on 178 Senegalese children were considered. A linear mixed-effect model was developed to take data dependence into account. This work showed that children with a light S. haematobium infection (1-9 eggs/mL of urine) presented lower P. falciparum parasite densities than children not infected by S. haematobium (P < 0.04). Possible changes caused by parasite coinfections should be considered in the anti-helminth treatment of children and in malaria vaccination development.
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Affiliation(s)
- Magali Lemaitre
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland; Institut de Recherche pour le Développement (UMR216), Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie, Paris, France; Faculté de pharmacie, Université Paris Descartes, Paris, France; Inserm, U657, Paris, F-75015, France; Institut Pasteur, PhEMI, Paris, F-75015, France; Univ. Versailles Saint Quentin, Faculté de Médecine Paris Ile de France Ouest, EA 4499, F-78035, France
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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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Rambau PF, Chalya PL, Jackson K. Schistosomiasis and urinary bladder cancer in North Western Tanzania: a retrospective review of 185 patients. Infect Agent Cancer 2013; 8:19. [PMID: 23705833 PMCID: PMC3665673 DOI: 10.1186/1750-9378-8-19] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 05/20/2013] [Indexed: 01/30/2023] Open
Abstract
Introduction Worldwide, cancers of the urinary bladder are well known to be associated with environmental chemical carcinogens such as smoking and occupational exposure to polycyclic aromatic hydrocarbons. These cancers are typically transitional cell carcinoma (urothelial carcinoma). In areas where schistosomiasis is endemic there is a high incidence of squamous cell carcinoma of the urinary bladder. Schistosomiasis causes chronic granulomatous cystitis leading to squamous metaplasia of transitional epithelium, and subsequently development of squamous cell carcinoma. The western part of Tanzania on the shores of Lake Victoria is such an endemic area. This study was done to document the burden of urinary bladder cancer associated with schistosomiasis in this region. Methods This was a descriptive retrospective study of histologically confirmed cases of urinary bladder cancer seen at the Department of Pathology Bugando Medical Centre (BMC) over a period of 10 years. Data were retrieved from the records of the Departments of Pathology, Medical Records and Surgery. Data were analyzed by the use of contingency tables. Results A total of 185 patients were diagnosed with cancer of the urinary bladder during the study period, where as 90 (48.6%) were males and 95 (51.4) were females. The mean age at diagnosis was 54.3 years. Squamous cell carcinoma was the most frequent histological type (55.1%), followed by conventional transitional cell carcinoma (40.5%). Eighty three of all cancer cases (44.9%) were found to have schistosomal eggs. Schistosomiasis was commonly associated with squamous cancers compared to non squamous cancers. Most of the cancers associated with schistosomiasis had invaded the muscularis propria of the urinary bladder at the time of diagnosis (p<0.001) and such cancers were frequent below 50 years of age with a significant statistical difference (p<0.001). Poorly differentiated tumors were more frequent in females than males with a significant statistical difference (p=0.006). Conclusion The majority of urinary bladder cancers seen in the Lake Region were squamous cell carcinoma associated with schistosomiasis. These cancers showed an aggressive behavior and were commonly seen in the younger age groups. Effective control of schistosomiasis in this region should significantly reduce the burden of urinary bladder cancer.
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Affiliation(s)
- Peter Fabian Rambau
- Department of Pathology, Catholic University of Health and Allied Sciences-Bugando (CUHAS-Bugando), Box 1464, Mwanza, Tanzania.
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Rujeni N, Nausch N, Midzi N, Gwisai R, Mduluza T, Taylor DW, Mutapi F. Soluble CD23 levels are inversely associated with atopy and parasite-specific IgE levels but not with polyclonal IgE levels in people exposed to helminth infection. Int Arch Allergy Immunol 2013; 161:333-41. [PMID: 23689700 PMCID: PMC3795451 DOI: 10.1159/000346545] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Accepted: 12/14/2012] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Protective acquired immunity against helminths and allergic sensitisation are both characterised by high IgE antibody levels. Levels of IgE antibodies are naturally tightly regulated by several mechanisms including binding of the CD23 receptor. Following observations that helminth infections and allergic sensitisation may co-present, the current study aims to investigate the relationship between the soluble CD23 (sCD23) receptor, parasite-specific IgE responses and allergic sensitisation in people exposed to the helminth parasite Schistosoma haematobium. METHODS A cohort of 434 participants was recruited in two villages with different levels of S. haematobium infection in Zimbabwe. Serum levels of the 25-kDa fragment of sCD23 were related to levels of schistosome infection intensity, allergen (house dust mite, HDM) and schistosome-specific IgE, total IgE and skin sensitisation to HDM. RESULTS sCD23 levels rose significantly with schistosome infection intensity but declined significantly with schistosome-specific IgE levels. Furthermore, sCD23 levels were negatively associated with skin sensitisation and IgE reactivity against HDM, but showed no relationship with total IgE. CONCLUSION The results are consistent with the suppression of parasite and allergen-specific IgE levels by sCD23. Further mechanistic studies will determine the relevance of this potential regulatory mechanism in the development of helminth-specific immune responses in atopic individuals.
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Affiliation(s)
- Nadine Rujeni
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories, Edinburgh, UK
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Yirenya-Tawiah D, Amoah C, Apea-Kubi KA, Dade M, Ackumey M, Annang T, Mensah DY, Bosompem KM. A survey of female genital schistosomiasis of the lower reproductive tract in the volta basin of Ghana. Ghana Med J 2013; 45:16-21. [PMID: 21572820 DOI: 10.4314/gmj.v45i1.68917] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE To determine the prevalence of female genital schistosomiasis in riparian communities in the Volta basin of Ghana, DESIGN The study was a cross-sectional study conducted among women 15-49 years in the Volta Basin. Urinary schistosomiasis prevalence was determined using microscopy. A structured questionnaire was also administered to collect information on the demography, obstetric history and reproductive health experiences. Cervical punch biopsy was collected from women who consented to be screened for FGS. Descriptive statistics was used to determine frequency of occurrence, chi squared and logistic regression to identify associated variables RESULTS Urinary schistosomiasis prevalence among the women was 24.8% while 10.6% of them diagnosed with FGS. More FGS diagnosed women (57.7%, p value =0.04%) were observed to report copious discharge, vaginal itch (80.8%, p=0.042) and lower abdominal pain (66.7%, p= 0.041) compared to FGS negative women. The predominant abnormal observation of the lower genital tract made was erythematous cervix (18.8%). CONCLUSION The study confirms the reproductive health symptoms associated with FGS and recommends awareness creation on FGS among women in endemic communities to facilitate early treatment.
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Affiliation(s)
- D Yirenya-Tawiah
- Volta Basin Research Project, University of Ghana, P.O. Box 209, Legon, Ghana.
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A new parasiticidal compound in T. solium cysticercosis. BIOMED RESEARCH INTERNATIONAL 2013; 2013:505240. [PMID: 23509732 PMCID: PMC3591161 DOI: 10.1155/2013/505240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 09/29/2012] [Accepted: 10/13/2012] [Indexed: 11/18/2022]
Abstract
The effect of 16α-bromoepiandrosterone (EpiBr), a dehydroepiandrosterone (DHEA) analogue, was tested on the cysticerci of Taenia solium, both in vitro and in vivo. In vitro treatment of T. solium cultures with EpiBr reduced scolex evagination, growth, motility, and viability in dose- and time-dependent fashions. Administration of EpiBr prior to infection with T. solium cysticerci in hamsters reduced the number and size of developed taenias in the intestine, compared with controls. These effects were associated to an increase in splenocyte proliferation in infected hamsters. These results leave open the possibility of assessing the potential of this hormonal analogue as a possible antiparasite drug, particularly in cysticercosis and taeniosis.
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Odiere MR, Rawago FO, Ombok M, Secor WE, Karanja DMS, Mwinzi PNM, Lammie PJ, Won K. High prevalence of schistosomiasis in Mbita and its adjacent islands of Lake Victoria, western Kenya. Parasit Vectors 2012. [PMID: 23206383 PMCID: PMC3523971 DOI: 10.1186/1756-3305-5-278] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Intestinal schistosomiasis continues to be a significant cause of morbidity among communities located around Lake Victoria and on its islands. Although epidemiological surveys have been conducted in other areas bordering the lake in western Kenya, Mbita district and its adjacent islands have never been surveyed, largely due to logistical challenges in accessing these areas. Consequently, there is a paucity of data on prevalence of schistosomiasis and soil-transmitted helminth (STH) infections that are endemic in this region. METHODS This cross-sectional study determined the prevalence, intensity of infection and geographical distribution of schistosome and STH infections among 4,065 children aged 5-19 years in 84 primary schools in Mbita and nearby islands of Lake Victoria (Mfangano, Ringiti, Rusinga and Takawiri), in western Kenya. Single stool samples were collected and examined for eggs of Schistosoma mansoni and STHs (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Primary schools were mapped using geographical information system data on PDAs and prevalence maps generated using ArcView GIS software. RESULTS Overall, 65.6% (95% CI = 64.2-67.1%) of children were infected with one or more helminth species; 12.4% (95% CI = 11.4-13.4%) of children were infected with one or more STH species. Mean school prevalence of S. mansoni infection was 60.5% (95% CI = 59.0-62.0%), hookworms 8.4% (95% CI = 7.6-9.3%), A. lumbricoides 3.3% (95% CI = 2.7-3.8%), and T. trichiura 1.6% (95% CI = 1.2-2.0%). Interestingly, the mean S. mansoni prevalence was 2-fold higher on the islands (82%) compared to the mainland (41%) (z = 5.8755, P < 0.0001). Similarly, intensity of infection was 54% higher on the islands (217.2 ± 99.3) compared to the mainland (141.3 ± 123.7) (z = 3.9374, P < 0.0001). Schools in closest proximity to Lake Victoria had the highest S. mansoni prevalence while prevalence of STHs was more homogenously distributed. CONCLUSIONS The very high prevalence of schistosomiasis in Mbita and the 4 islands is quite alarming, and indicates an urgent and critical need for control interventions. Findings from this survey indicate the need to implement treatment in remote areas not previously covered by mass drug administration programs.
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Affiliation(s)
- Maurice R Odiere
- Neglected Tropical Diseases Branch, Centre for Global Health Research, Kenya Medical Research Institute, P, O, Box 1578-40100, Kisumu, Kenya.
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Bottasso O, Bay ML, Besedovsky H, Del Rey A. Adverse neuro-immune-endocrine interactions in patients with active tuberculosis. Mol Cell Neurosci 2012; 53:77-85. [PMID: 23147110 DOI: 10.1016/j.mcn.2012.11.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 11/01/2012] [Accepted: 11/02/2012] [Indexed: 12/21/2022] Open
Abstract
The nervous, endocrine and immune systems play a crucial role in maintaining homeostasis and interact with each other for a successful defensive strategy against injurious agents. However, the situation is different in long-term diseases with marked inflammation, in which defensive mechanisms become altered. In the case of tuberculosis (TB), this is highlighted by several facts: an imbalance of plasma immune and endocrine mediators, that results in an adverse environment for mounting an adequate response against mycobacteria and controlling inflammation; the demonstration that dehidroepiandrosterone (DHEA) secretion by a human adrenal cell line can be inhibited by culture supernatants from Mycobacterium tuberculosis-stimulated peripheral blood mononuclear cells - PBMC - of TB patients, with this effect being partly reverted when neutralizing transforming growth factor-β in such supernantants; the in vitro effects of adrenal steroids on the specific immune response of PBMC from TB patients, that is a cortisol inhibition of mycobacterial antigen-driven lymphoproliferation and interferon-γ production as well as a suppression of TGF-β production in DHEA-treated PBMC; and lastly the demonstration that immune and endocrine compounds participating in the regulation of energy sources and immune activity correlated with the consumption state of TB patients. Collectively, immune-endocrine disturbances of TB patients are involved in critical components of disease pathology with implications in the impaired clinical status and unfavorable disease outcome. This article is part of a Special Issue entitled 'Neuroinflammation in neurodegeneration and neurodysfunction'.
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Affiliation(s)
- Oscar Bottasso
- Instituto de Inmunología, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Argentina.
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Effects of treatment on IgE responses against parasite allergen-like proteins and immunity to reinfection in childhood schistosome and hookworm coinfections. Infect Immun 2012; 81:23-32. [PMID: 23071136 DOI: 10.1128/iai.00748-12] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Naturally occurring human immunity to both schistosomiasis and hookworm infection has been associated with IgE responses against parasite allergen-like proteins. Since the two helminths frequently coinfect the same individuals, there is growing advocacy for their concurrent treatment. However, both helminths are known to exert strong immunomodulatory effects; therefore, coinfected individuals could have immune responses different from those characteristically seen in monoinfected individuals. In this study, we measured changes in IgE, IgG1, and IgG4 responses to schistosome and hookworm antigens, including the allergen-like proteins Schistosoma mansoni tegumental-allergen-like 1 protein (SmTAL1), SmTAL2, and Necator americanus Ancylostoma-secreted protein-2 (Na-ASP-2), following concurrent treatment of schoolchildren coinfected with Schistosoma mansoni and hookworm. Antibody responses to schistosome egg (soluble egg antigen and SmTAL2) or somatic adult hookworm (AHW) antigens either decreased after treatment or were unchanged, whereas those to schistosome worm antigens (soluble worm antigen and SmTAL1) increased. The observed different effects of treatment likely reflect the different modes of drug action and sites of infection for these two helminths. Importantly, there was no evidence that the simultaneous treatment of coinfected children with praziquantel and albendazole affected schistosome- and hookworm-specific humoral responses differently from those characteristic of populations in which only one organism is endemic; schistosome- and hookworm-specific responses were not associated, and there was no evidence for cross-regulation. Posttreatment increases in the levels of IgE to schistosome worm antigens were associated with lower Schistosoma mansoni reinfection intensity, while no associations between humoral responses to AHW antigen and protection from hookworm reinfection were observed in this sample of school-aged children.
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Rujeni N, Taylor DW, Mutapi F. Human schistosome infection and allergic sensitisation. J Parasitol Res 2012; 2012:154743. [PMID: 22970345 PMCID: PMC3434398 DOI: 10.1155/2012/154743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/28/2012] [Indexed: 12/24/2022] Open
Abstract
Several field studies have reported an inverse relationship between the prevalence of helminth infections and that of allergic sensitisation/atopy. Recent studies show that immune responses induced by helminth parasites are, to an extent, comparable to allergic sensitisation. However, helminth products induce regulatory responses capable of inhibiting not only antiparasite immune responses, but also allergic sensitisation. The relative effects of this immunomodulation on the development of protective schistosome-specific responses in humans has yet to be demonstrated at population level, and the clinical significance of immunomodulation of allergic disease is still controversial. Nonetheless, similarities in immune responses against helminths and allergens pose interesting mechanistic and evolutionary questions. This paper examines the epidemiology, biology and immunology of allergic sensitisation/atopy, and schistosome infection in human populations.
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Affiliation(s)
- Nadine Rujeni
- Institute of Immunology and Infection Research, Centre for Immunity, Infection, and Evolution, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Rd, Edinburgh EH9 3JT, UK
| | - David W. Taylor
- Institute of Immunology and Infection Research, Centre for Immunity, Infection, and Evolution, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Rd, Edinburgh EH9 3JT, UK
| | - Francisca Mutapi
- Institute of Immunology and Infection Research, Centre for Immunity, Infection, and Evolution, School of Biological Sciences, University of Edinburgh, Ashworth Laboratories, King's Buildings, West Mains Rd, Edinburgh EH9 3JT, UK
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Paradigm lost: how parasite control may alter pattern and process in human helminthiases. Trends Parasitol 2012; 28:161-71. [DOI: 10.1016/j.pt.2012.02.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 02/07/2012] [Accepted: 02/07/2012] [Indexed: 11/22/2022]
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Walker M, Little MP, Wagner KS, Soumbey-Alley EW, Boatin BA, Basáñez MG. Density-dependent mortality of the human host in onchocerciasis: relationships between microfilarial load and excess mortality. PLoS Negl Trop Dis 2012; 6:e1578. [PMID: 22479660 PMCID: PMC3313942 DOI: 10.1371/journal.pntd.0001578] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Accepted: 02/09/2012] [Indexed: 11/23/2022] Open
Abstract
Background The parasite Onchocerca volvulus has, until recently, been regarded as the cause of a chronic yet non-fatal condition. Recent analyses, however, have indicated that in addition to blindness, the parasite can also be directly associated with human mortality. Such analyses also suggested that the relationship between microfilarial load and excess mortality might be non-linear. Determining the functional form of such relationship would contribute to quantify the population impact of mass microfilaricidal treatment. Methodology/Principal Findings Data from the Onchocerciasis Control Programme in West Africa (OCP) collected from 1974 through 2001 were used to determine functional relationships between microfilarial load and excess mortality of the human host. The goodness-of-fit of three candidate functional forms (a (log-) linear model and two saturating functions) were explored and a saturating (log-) sigmoid function was deemed to be statistically the best fit. The excess mortality associated with microfilarial load was also found to be greater in younger hosts. The attributable mortality risk due to onchocerciasis was estimated to be 5.9%. Conclusions/Significance Incorporation of this non-linear functional relationship between microfilarial load and excess mortality into mathematical models for the transmission and control of onchocerciasis will have important implications for our understanding of the population biology of O. volvulus, its impact on human populations, the global burden of disease due to onchocerciasis, and the projected benefits of control programmes in both human and economic terms. Human onchocerciasis (River Blindness) is a parasitic disease leading to visual impairment including blindness. Blindness may lead to premature death, but infection with the parasite itself (Onchocerca volvulus) may also cause excess mortality in sighted individuals. The excess risk of mortality may not be directly (linearly) proportional to the intensity of infection (a measure of how many parasites an individual harbours). We analyze cohort data from the Onchocerciasis Control Programme in West Africa, collected between 1974 and 2001, by fitting a suite of quantitative models (including a ‘null’ model of no relationship between infection intensity and mortality, a (log-) linear function, and two plateauing curves), and choosing the one that is the most statistically adequate. The risk of human mortality initially increases with parasite density but saturates at high densities (following an S-shape curve), and such risk is greater in younger individuals for a given infection intensity. Our results have important repercussions for programmes aiming to control onchocerciasis (in terms of how the benefits of the programme are calculated), for measuring the burden of disease and mortality caused by the infection, and for a better understanding of the processes that govern the density of parasite populations among human hosts.
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Affiliation(s)
- Martin Walker
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Mark P. Little
- Department of Epidemiology and Biostatistics, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Karen S. Wagner
- Travel and Migrant Health Section, Health Protection Agency Centre for Infections, London, United Kingdom
| | - Edoh W. Soumbey-Alley
- Health Information Systems, World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Boakye A. Boatin
- Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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Kjetland EF, Leutscher PD, Ndhlovu PD. A review of female genital schistosomiasis. Trends Parasitol 2012; 28:58-65. [DOI: 10.1016/j.pt.2011.10.008] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2011] [Revised: 10/23/2011] [Accepted: 10/24/2011] [Indexed: 12/21/2022]
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Wilson MS, Cheever AW, White SD, Thompson RW, Wynn TA. IL-10 blocks the development of resistance to re-infection with Schistosoma mansoni. PLoS Pathog 2011; 7:e1002171. [PMID: 21829367 PMCID: PMC3150278 DOI: 10.1371/journal.ppat.1002171] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 06/03/2011] [Indexed: 01/26/2023] Open
Abstract
Despite effective chemotherapy to treat schistosome infections, re-infection rates are extremely high. Resistance to reinfection can develop, however it typically takes several years following numerous rounds of treatment and re-infection, and often develops in only a small cohort of individuals. Using a well-established and highly permissive mouse model, we investigated whether immunoregulatory mechanisms influence the development of resistance. Following Praziquantel (PZQ) treatment of S. mansoni infected mice we observed a significant and mixed anti-worm response, characterized by Th1, Th2 and Th17 responses. Despite the elevated anti-worm response in PBMC's, liver, spleen and mesenteric lymph nodes, this did not confer any protection from a secondary challenge infection. Because a significant increase in IL-10-producing CD4+CD44+CD25+GITR+ lymphocytes was observed, we hypothesised that IL-10 was obstructing the development of resistance. Blockade of IL-10 combined with PZQ treatment afforded a greater than 50% reduction in parasite establishment during reinfection, compared to PZQ treatment alone, indicating that IL-10 obstructs the development of acquired resistance. Markedly enhanced Th1, Th2 and Th17 responses, worm-specific IgG1, IgG2b and IgE and circulating eosinophils characterized the protection. This study demonstrates that blocking IL-10 signalling during PZQ treatment can facilitate the development of protective immunity and provide a highly effective strategy to protect against reinfection with S. mansoni. Schistosomes are zoonotic parasitic helminths that infect hundreds of millions of people worldwide. Despite effective chemotherapy, schistosomiasis- the disease caused by these parasites, still plagues tropical regions of the world. This is due, in part, to poor resistance to reinfection resulting in high re-infection rates following treatment. This lack of resistance is intriguing, as effective treatment relies upon drug-induced parasite damage combined with host immune mediated killing. Furthermore, it has been widely reported that post-treatment, individuals develop and retain elevated levels of anti-parasite immune responses. We therefore asked why resistance to re-infection is so poor, despite the development of significant anti-worm responses post-treatment. It is essential that immune responses are controlled by various immunosuppressive mechanisms to prevent immune-mediated pathologies. However, a robust immunoregulatory response may obstruct the development of protective immunity. Thus, a balanced immune response providing a non-pathogenic yet effective immune response may be required for the development of effective resistance to reinfection. Understanding the immunological mechanisms of resistance to re-infection and the role of effector and regulatory responses may aid in the development of more effective vaccines and treatment strategies for schistosomaisis. This study suggests that combining chemotherapy with drugs that block IL-10 might provide an improved strategy to elicit acquired immunity to this parasite.
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Affiliation(s)
- Mark S Wilson
- Immunopathogensis Section, Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Marlyand, United States of America.
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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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Bethony JM, Cole RN, Guo X, Kamhawi S, Lightowlers MW, Loukas A, Petri W, Reed S, Valenzuela JG, Hotez PJ. Vaccines to combat the neglected tropical diseases. Immunol Rev 2011; 239:237-70. [PMID: 21198676 DOI: 10.1111/j.1600-065x.2010.00976.x] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The neglected tropical diseases (NTDs) represent a group of parasitic and related infectious diseases such as amebiasis, Chagas disease, cysticercosis, echinococcosis, hookworm, leishmaniasis, and schistosomiasis. Together, these conditions are considered the most common infections in low- and middle-income countries, where they produce a level of global disability and human suffering equivalent to better known conditions such as human immunodeficiency virus/acquired immunodeficiency syndrome and malaria. Despite their global public health importance, progress on developing vaccines for NTD pathogens has lagged because of some key technical hurdles and the fact that these infections occur almost exclusively in the world's poorest people living below the World Bank poverty line. In the absence of financial incentives for new products, the multinational pharmaceutical companies have not embarked on substantive research and development programs for the neglected tropical disease vaccines. Here, we review the current status of scientific and technical progress in the development of new neglected tropical disease vaccines, highlighting the successes that have been achieved (cysticercosis and echinococcosis) and identifying the challenges and opportunities for development of new vaccines for NTDs. Also highlighted are the contributions being made by non-profit product development partnerships that are working to overcome some of the economic challenges in vaccine manufacture, clinical testing, and global access.
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Affiliation(s)
- Jeffrey M Bethony
- Microbiology, Immunology, and Tropical Medicine, George Washington University Medical Center, Washington, DC 20037, USA.
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Abstract
A characteristic relationship between infection and host age, with levels of infection reaching a peak in particular age classes, has been reported for many parasites. However, several field studies have shown that this relationship is not invariant: if age-infection data are compared across host populations, the peak level of infection is higher and occurs at a younger age when the transmission rate is high, and is lower and occurs at an older age when it is low. This pattern is called the ;peak shift'. Here, Mark Woolhouse reviews the evidence for and the implications of the peak shift. The peak shift is consistent with the predictions of mathematical models that assume gradually acquired protective immunity, and this interpretation is supported by experimental studies using animals. This agreement between theory, experimental evidence and field studies strongly suggests that acquired immunity has a major impact on epidemiological patterns not only for parasites such as malaria, where the importance of acquired immunity is not in doubt, but also for many parasitic helminths, where the role of acquired immunity is less widely accepted.
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Affiliation(s)
- M E Woolhouse
- Centre for Tropical Veterinary Medicine, University of Edinburgh, Easter Bush, Roslin, Midlothian, UK EH25 9RG
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Abstract
Schistosome vaccine candidates are now entering phase I clinical trials. In an attempt to illustrate the progress made towards control, and the definition of potential vaccines against schistosomiasis, André Capron reviews some of the major findings and observations that have led to a significant evolution of our concepts, together with the production of novel and promising tools. It is obvious that our most important advances have proceeded from the successful integration of convergent knowledge in biology, epidemiology and biotechnology. At this stage, nobody can predict what will be the outcome of the current trials, but an important step has certainly been made towards immunointervention in human schistosomiasis.
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Affiliation(s)
- A Capron
- Pasteur Institut de Lille, 1 rue du Prof. A. Calmette, BP 245, 59019 Lille Cedex, France
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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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Abstract
Over the past 30 years there has been a concerted effort to understand host immune responses to schistosomes, with the ultimate aim of producing a vaccine for human use. In this issue, Bergquist and Colley, in summarizing recent meetings in Cairo, provide a detailed appraisal of progress towards that goal. It seems an appropriate time to ask why, with reference to Schistosoma mansoni, the development of a vaccine has proved so difficult. This question is explored here by Alan Wilson and Pat Coulson.
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Geographical distribution of schistosomiasis and soil-transmitted helminths among school children in informal settlements in Kisumu City, Western Kenya. Parasitology 2011; 138:1569-77. [PMID: 21679486 DOI: 10.1017/s003118201100059x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This cross-sectional study determined the prevalence and distribution of schistosome and soil-transmitted helminth (STH) infections among 1,308 children aged 10-18 years in 34 primary schools in 8 informal urban settlements in Kisumu City, western Kenya. Stool samples were collected and examined for eggs of Schistosoma mansoni and STH (Hookworms, Ascaris lumbricoides and Trichuris trichiura) using the Kato-Katz technique. Haematuria was used as a proxy indicator of urinary schistosomiasis. Schools and water bodies were mapped using a geographical information system. Overall, 34% of children were infected with one or more helminth species whereas 16·2% of children were infected with one or more STH species. Schools in closest proximity to Lake Victoria and River Nyamasaria had the highest S. mansoni prevalence while schools with STH were more homogenously distributed. Mean school prevalence of S. mansoni infection was 21% (range=0-69·7%), S. haematobium 3·6% (range=0-12%), hookworms 6·1% (range=0-20%), A. lumbricoides 4·9% (range=0-18·4%), and T. trichiura 7·7% (range=0-18·6%). Helminth-related morbidities were not associated with infection. Our study demonstrates that schistosomiasis and STH are important health priorities among schools in informal settlements of Kisumu City, and highlights the need for routine deworming in similar settings.
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Tarafder MR, Carabin H, McGarvey ST, Joseph L, Balolong E, Olveda R. Assessing the impact of misclassification error on an epidemiological association between two helminthic infections. PLoS Negl Trop Dis 2011; 5:e995. [PMID: 21468317 PMCID: PMC3066162 DOI: 10.1371/journal.pntd.0000995] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 03/03/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Polyparasitism can lead to severe disability in endemic populations. Yet, the association between soil-transmitted helminth (STH) and the cumulative incidence of Schistosoma japonicum infection has not been described. The aim of this work was to quantify the effect of misclassification error, which occurs when less than 100% accurate tests are used, in STH and S. japonicum infection status on the estimation of this association. METHODOLOGY/PRINCIPAL FINDINGS Longitudinal data from 2276 participants in 50 villages in Samar province, Philippines treated at baseline for S. japonicum infection and followed for one year, served as the basis for this analysis. Participants provided 1-3 stool samples at baseline and 12 months later (2004-2005) to detect infections with STH and S. japonicum using the Kato-Katz technique. Variation from day-to-day in the excretion of eggs in feces introduces individual variations in the sensitivity and specificity of the Kato-Katz to detect infection. Bayesian logit models were used to take this variation into account and to investigate the impact of misclassification error on the association between these infections. Uniform priors for sensitivity and specificity of the diagnostic test to detect the three STH and S. japonicum were used. All results were adjusted for age, sex, occupation, and village-level clustering. Without correction for misclassification error, the odds ratios (ORs) between hookworm, Ascaris lumbricoides, and Trichuris trichiura, and S. japonicum infections were 1.28 (95% Bayesian credible intervals: 0.93, 1.76), 0.91 (95% BCI: 0.66, 1.26), and 1.11 (95% BCI: 0.80, 1.55), respectively, and 2.13 (95% BCI: 1.16, 4.08), 0.74 (95% BCI: 0.43, 1.25), and 1.32 (95% BCI: 0.80, 2.27), respectively, after correction for misclassification error for both exposure and outcome. CONCLUSIONS/SIGNIFICANCE The misclassification bias increased with decreasing test accuracy. Hookworm infection was found to be associated with increased 12-month cumulative incidence of S. japonicum infection after correction for misclassification error. Such important associations might be missed in analyses which do not adjust for misclassification errors.
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Affiliation(s)
- Mushfiqur R Tarafder
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America.
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Griffith QK, Liang Y, Onguru DO, Mwinzi PN, Ganley-Leal LM. CD23-bound IgE augments and dominates recall responses through human naive B cells. THE JOURNAL OF IMMUNOLOGY 2010; 186:1060-7. [PMID: 21160045 DOI: 10.4049/jimmunol.1002709] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human peripheral blood BCRμ(+) B cells express high levels of CD23 and circulate preloaded with IgE. The Ag specificity of CD23-bound IgE presumably differs from the BCR and likely reflects the Ag-specific mix of free serum IgE. CD23-bound IgE is thought to enhance B cell Ag presentation to T cells raising the question of how a B cell might respond when presented with a broad mix of Ags and CD23-bound IgE specificities. We recently reported that an increase in CD23(+) B cells is associated with the development of resistance to schistosomiasis, highlighting the potential importance of CD23-bound IgE in mediating immunity. We sought to determine the relationship between BCR and CD23-bound IgE-mediated B cell activation in the context of schistosomiasis. We found that crude schistosome Ags downregulate basal B cell activation levels in individuals hyperexposed to infectious worms. Schistosome-specific IgE from resistant, occupationally exposed Kenyans recovered responses of B cells to schistosome Ag. Furthermore, cross-linking of CD23 overrode intracellular signals mediated via the BCR, illustrating its critical and dominating role in B cell activation. These results suggest that CD23-bound IgE augments and dominates recall responses through naive B cells.
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Affiliation(s)
- Qyana K Griffith
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA
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Abdul-Ghani RA, Hassan AA. Murine schistosomiasis as a model for human schistosomiasis mansoni: similarities and discrepancies. Parasitol Res 2010; 107:1-8. [DOI: 10.1007/s00436-010-1855-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 03/18/2010] [Indexed: 11/25/2022]
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Pereira WR, Kloos H, Crawford SB, Velásquez-Melendez JG, Matoso LF, Fujiwara RT, Cançado GGL, Loverde PT, Correa-Oliveira R, Gazzinelli A. Schistosoma mansoni infection in a rural area of the Jequitinhonha Valley, Minas Gerais, Brazil: analysis of exposure risk. Acta Trop 2010; 113:34-41. [PMID: 19765542 DOI: 10.1016/j.actatropica.2009.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 08/05/2009] [Accepted: 09/09/2009] [Indexed: 11/18/2022]
Abstract
This study examines the relative contribution of age-specific total IgE levels, eosinophils and water contact behavior to the prevalence and intensity (geometric mean egg counts) of Schistosoma mansoni infection in the poor rural population of Virgem das Graças in northern Minas Gerais State. In bivariate analysis, age was strongly correlated with both prevalence and intensity of infection, while eosinophil levels with prevalence only (p<0.0001); IgE levels and 5 demographic and socioeconomic variables were moderately correlated with prevalence (p<0.05), as were number of persons per room and TBM (total body minutes) with egg counts. In multivariate analysis, after controlling for demographic and socioeconomic factors, only total IgE levels were significantly correlated with both prevalence (p=0.248, 95% CI=1.01-1.11) and intensity (p=0.0217, 95% CI=0.01-0.14) of infection and eosinophil levels with prevalence (p=0.0005, 95% CI=1.07-1.24). Although any causal relationship cannot be confirmed by a cross-sectional study, we demonstrated an associated decrease in prevalence and intensity of S. mansoni infection with increased IgE levels.
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Affiliation(s)
- Wesley Rodrigues Pereira
- Laboratory of Cellular and Molecular Immunology, Centro de Pesquisas René Rachou/FIOCRUZ, Brazil
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Pullan RL, Bethony JM, Geiger SM, Correa-Oliveira R, Brooker S, Quinnell RJ. Human helminth co-infection: no evidence of common genetic control of hookworm and Schistosoma mansoni infection intensity in a Brazilian community. Int J Parasitol 2009; 40:299-306. [PMID: 19699204 DOI: 10.1016/j.ijpara.2009.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Revised: 08/10/2009] [Accepted: 08/11/2009] [Indexed: 10/20/2022]
Abstract
Strong statistical associations between soil-transmitted helminths and schistosomes are frequently observed in co-endemic human populations, although the underlying explanations remain poorly understood. This study investigates the contribution of host genetics and domestic environment to hookworm and Schistosoma mansoni infection intensity and evaluates the role of genetic and non-genetic factors in co-variation of infection intensity. Detailed genealogical information allowed assignment of 1303 individuals living in the Brazilian community of Americaninhas, Minas Gerais state, to 25 pedigrees (containing between two and 1159 members) residing in 303 households. The prevalence of co-infection with both hookworms and schistosomes was high (38.5%), with significant correlation between Necator americanus and S. mansoni faecal egg counts. Bivariate variance component analysis demonstrated a modest but significant species-specific heritability for intensity of N. americanus (h(2)=0.196) and S. mansoni infection (h(2)=0.230). However, after accounting for demographic, socio-economic and household risk factors, no evidence for common genetic control of intensity of hookworm and schistosome infection was observed. There was some evidence for residual clustering within households but the majority (63%) of the covariance between N. americanus and S. mansoni infection intensity remained specific to the individual and could not be explained by shared genes, shared environment or other shared demographic, socio-economic or environmental risk factors. Our results emphasize the importance of exposure to hookworm and schistosome infection in driving the association between levels of infection with these species in hosts resident in areas of high transmission and suggest that much of this common exposure occurs outside the home.
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Affiliation(s)
- Rachel L Pullan
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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Clements ACA, Firth S, Dembelé R, Garba A, Touré S, Sacko M, Landouré A, Bosqué-Oliva E, Barnett AG, Brooker S, Fenwick A. Use of Bayesian geostatistical prediction to estimate local variations in Schistosoma haematobium infection in western Africa. Bull World Health Organ 2009; 87:921-9. [PMID: 20454483 DOI: 10.2471/blt.08.058933] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 01/28/2009] [Accepted: 02/04/2009] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To predict the subnational spatial variation in the number of people infected with Schistosoma haematobium in Burkina Faso, Mali and the Niger prior to national control programmes. METHODS We used field survey data sets covering a contiguous area 2750 x 850 km and including 26,790 school-age children (5-14 years old) in 418 schools. The prevalence of high- and low-intensity infection and associated 95% credible intervals (CrIs) were predicted using Bayesian geostatistical models. The number infected was determined from the predicted prevalence and the number of school-age children in each km(2). FINDINGS The predicted number of school-age children with a low-intensity infection was 433,268 in Burkina Faso, 872,328 in Mali and 580 286 in the Niger. The number with a high-intensity infection was 416,009, 511,845 and 254,150 in each country, respectively. The 95% CrIs were wide: e.g. the mean number of boys aged 10-14 years infected in Mali was 140,200 (95% CrI: 6200-512,100). CONCLUSION National aggregate estimates of infection mask important local variations:: e.g. most S. haematobium infections in the Niger occur in the Niger River valley. High-intensity infection was strongly clustered in western and central Mali, north-eastern and northwestern Burkina Faso and the Niger River valley in the Niger. Populations in these foci will carry the bulk of the urinary schistosomiasis burden and should be prioritized for schistosomiasis control. Uncertainties in the predicted prevalence and the numbers infected should be acknowledged by control programme planners.
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Affiliation(s)
- Archie C A Clements
- University of Queensland, School of Population Health, Herston Road, Herston, Qld, 4006, Australia.
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Lillerud LE, Stuestoel VM, Hoel RE, Rukeba Z, Kjetland EF. Exploring the feasibility and possible efficacy of mass treatment and education of young females as schistosomiasis influences the HIV epidemic. Arch Gynecol Obstet 2009; 281:455-60. [DOI: 10.1007/s00404-009-1108-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 04/23/2009] [Indexed: 11/27/2022]
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