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Mrimi EC, Palmeirim MS, Minja EG, Long KZ, Keiser J. Correlation of Cytokines with Parasitic Infections, Undernutrition and Micronutrient Deficiency among Schoolchildren in Rural Tanzania: A Cross-Sectional Study. Nutrients 2023; 15:nu15081916. [PMID: 37111135 PMCID: PMC10145041 DOI: 10.3390/nu15081916] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/11/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Malnutrition and parasitic infections are often interconnected in a vicious cycle. Malnutrition can lead to changes in immune response, which may affect cytokine concentrations and potentially increase susceptibility to infections. In turn, parasitic infections can exacerbate malnutrition by impairing nutrient absorption. This cross-sectional study aimed to explore this interplay. Schoolchildren aged 6-12 years living in rural Tanzania (n = 120) provided blood, stool and urine samples to determine the relationship between cytokine concentrations (interleukin 4 (IL-4), interferon gamma (IFNγ) and interleukin 17A (IL-17A)), parasitic infections, undernutrition and micronutrient deficiency adjusting for sex, age, inflammatory markers, socioeconomic status and school categories. All schoolchildren had a normal blood cell count. The concentration of IL-4 was significantly higher in schoolchildren diagnosed with stunting, Schistosoma mansoni infection, a high C-reactive protein concentration, nausea, poor housing and increasing age. The concentration of IFNγ was associated with Plasmodium falciparum and Entamoeba histolytica/Entamoeba dispar/Entamoeba moshkovskii infections, vitamin A deficiency, attending the most remote schools and low socioeconomic status. Our study confirms a potential relationship between cytokine concentrations and parasitic infections, malnutrition and low socioeconomic status. A better understanding of long-term effects of parasitic infections and malnutrition on the immune function could help in designing tailored and effective interventions.
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Affiliation(s)
- Emmanuel C Mrimi
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
- Ifakara Health Institute, Morogoro P.O. Box 53, Tanzania
| | - Marta S Palmeirim
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Elihaika G Minja
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
- Ifakara Health Institute, Morogoro P.O. Box 53, Tanzania
| | - Kurt Z Long
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Jennifer Keiser
- Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
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Bancroft AJ, Grencis RK. Immunoregulatory molecules secreted by Trichuris muris. Parasitology 2021; 148:1-7. [PMID: 34075864 PMCID: PMC8660643 DOI: 10.1017/s0031182021000846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/17/2021] [Accepted: 05/20/2021] [Indexed: 12/19/2022]
Abstract
Trichuris, whipworm nematode infections are prevalent in humans, domestic livestock and mammals. All share an epithelial dwelling niche and similar life cycle with the chronic infections that follow implying that immune evasion mechanisms are operating. Nematode excretory secretory (ES) products have been shown to be a rich source of immunomodulatory molecules for many species. The Trichuris muris model is a natural parasite of mice and has been used extensively to study host–parasite interactions and provides a tractable platform for investigation of the immunoregulatory capacity of whipworm ES. The present review details progress in identification of the composition of T. muris ES, immunomodulatory components and their potential mechanisms of action. The adult T. muris secretome is dominated by one protein with modulatory capacity although remains to be completely characterized. In addition, the secretome contains multiple other proteins and small molecules that have immunomodulatory potential, certainly by comparison to other Trichuris species. Moreover, T. muris-derived exosomes/exosome-like vesicles contain both protein and multiple miRNAs providing an alternate delivery process for molecules with the potential to modulate host immunity.
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Affiliation(s)
- Allison J. Bancroft
- Lydia Becker Institute for Immunology and Inflammation, ManchesterM13 9PT, UK
- Wellcome Trust Centre for Cell Matrix Research, Manchester M13 9PT, UK
- Division of Infection, Immunity and Respiratory Medicine, ManchesterM13 9PT, UK
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, ManchesterM13 9PL, UK
| | - Richard K. Grencis
- Lydia Becker Institute for Immunology and Inflammation, ManchesterM13 9PT, UK
- Wellcome Trust Centre for Cell Matrix Research, Manchester M13 9PT, UK
- Division of Infection, Immunity and Respiratory Medicine, ManchesterM13 9PT, UK
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, ManchesterM13 9PL, UK
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Nongmaithem O, Shantikumar T, Dutta S. Evaluation of various culture techniques for identification of hookworm species from stool samples of children. Indian J Med Res 2019; 149:539-543. [PMID: 31411178 PMCID: PMC6676850 DOI: 10.4103/ijmr.ijmr_938_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background & objectives Different coproculture techniques have been developed for culturing the hookworm (HW) larvae for morphological identification in the resource-limited settings. The objective of this study was to compare the performances of Harada-Mori culture (HMC), agar plate culture (APC) and modified APC (MAPC) of HW positive stool specimens for identification of HW species in East Sikkim. Methods This prospective study was done in East Sikkim from May 2015 to May 2016. Stool and blood samples were collected from paediatric patients with gastrointestinal symptoms. The HW positive stool specimens by microscopy were subjected to HMC, APC and MAPC techniques to harvest HW larvae. Stoll's dilution egg count for determining egg intensity and blood parameters were performed in all the 12 HW-positive patients. Results Twelve of the 180 samples were found positive for HW by microscopy and predominance of Necator americanus (75%) over Ancylostoma duodenale (25%) was observed. Blood parameters results showed high pack cell volume (PCV) values in 78.6 per cent, anaemia in 75 per cent and high eosinophil count in most patients. Stoll's dilution egg count showed moderate infection in 66.6 per cent, light and heavy infections in 16.7 per cent each. Interpretation & conclusions Our results showed that APC yielded 100 per cent results and was easier to perform in the laboratory compared to MAPC and HMC techniques.
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Affiliation(s)
- Onila Nongmaithem
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Gangtok, India
| | - T Shantikumar
- Department of Microbiology, Sikkim Manipal Institute of Medical Sciences, Gangtok, India
| | - Sudip Dutta
- Department of Pediatrics, Sikkim Manipal Institute of Medical Sciences, Gangtok, India
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Wright JE, Werkman M, Dunn JC, Anderson RM. Current epidemiological evidence for predisposition to high or low intensity human helminth infection: a systematic review. Parasit Vectors 2018; 11:65. [PMID: 29382360 PMCID: PMC5791198 DOI: 10.1186/s13071-018-2656-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 01/17/2018] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The human helminth infections include ascariasis, trichuriasis, hookworm infections, schistosomiasis, lymphatic filariasis (LF) and onchocerciasis. It is estimated that almost 2 billion people worldwide are infected with helminths. Whilst the WHO treatment guidelines for helminth infections are mostly aimed at controlling morbidity, there has been a recent shift with some countries moving towards goals of disease elimination through mass drug administration, especially for LF and onchocerciasis. However, as prevalence is driven lower, treating entire populations may no longer be the most efficient or cost-effective strategy. Instead, it may be beneficial to identify individuals or demographic groups who are persistently infected, often termed as being "predisposed" to infection, and target treatment at them. METHODS The authors searched Embase, MEDLINE, Global Health, and Web of Science for all English language, human-based papers investigating predisposition to helminth infections published up to October 31st, 2017. The varying definitions used to describe predisposition, and the statistical tests used to determine its presence, are summarised. Evidence for predisposition is presented, stratified by helminth species, and risk factors for predisposition to infection are identified and discussed. RESULTS In total, 43 papers were identified, summarising results from 34 different studies in 23 countries. Consistent evidence of predisposition to infection with certain species of human helminth was identified. Children were regularly found to experience greater predisposition to Ascaris lumbricoides, Schistosoma mansoni and S. haematobium than adults. Females were found to be more predisposed to A. lumbricoides infection than were males. Household clustering of infection was identified for A. lumbricoides, T. trichiura and S. japonicum. Ascaris lumbricoides and T. trichiura also showed evidence of familial predisposition. Whilst strong evidence for predisposition to hookworm infection was identified, findings with regards to which groups were affected were considerably more varied than for other helminth species. CONCLUSION This review has found consistent evidence of predisposition to heavy (and light) infection for certain human helminth species. However, further research is needed to identify reasons for the reported differences between demographic groups. Molecular epidemiological methods associated with whole genome sequencing to determine 'who infects whom' may shed more light on the factors generating predisposition.
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Affiliation(s)
- James E. Wright
- 0000 0001 2113 8111grid.7445.2Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, London, W2 1PG UK
- 0000 0001 2113 8111grid.7445.2London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Campus, London, W2 1PG UK
- 0000 0001 2172 097Xgrid.35937.3bThe DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD UK
| | - Marleen Werkman
- 0000 0001 2113 8111grid.7445.2Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, London, W2 1PG UK
- 0000 0001 2113 8111grid.7445.2London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Campus, London, W2 1PG UK
- 0000 0001 2172 097Xgrid.35937.3bThe DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD UK
| | - Julia C. Dunn
- 0000 0001 2113 8111grid.7445.2Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, London, W2 1PG UK
- 0000 0001 2113 8111grid.7445.2London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Campus, London, W2 1PG UK
| | - Roy M. Anderson
- 0000 0001 2113 8111grid.7445.2Department of Infectious Disease Epidemiology, Imperial College London, St. Mary’s Campus, London, W2 1PG UK
- 0000 0001 2113 8111grid.7445.2London Centre for Neglected Tropical Disease Research (LCNTDR), Department of Infectious Disease Epidemiology, Imperial College London, St Mary’s Campus, London, W2 1PG UK
- 0000 0001 2172 097Xgrid.35937.3bThe DeWorm3 Project, The Natural History Museum of London, London, SW7 5BD UK
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Jourdan PM, Lamberton PHL, Fenwick A, Addiss DG. Soil-transmitted helminth infections. Lancet 2018; 391:252-265. [PMID: 28882382 DOI: 10.1016/s0140-6736(17)31930-x] [Citation(s) in RCA: 372] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/13/2017] [Accepted: 06/23/2017] [Indexed: 12/13/2022]
Abstract
More than a quarter of the world's population is at risk of infection with the soil-transmitted helminths Ascaris lumbricoides, hookworm (Ancylostoma duodenale and Necator americanus), Trichuris trichiura, and Strongyloides stercoralis. Infected children and adults present with a range of medical and surgical conditions, and clinicians should consider the possibility of infection in individuals living in, or returning from, endemic regions. Although safe and effective drugs are donated free to endemic countries, only half of at-risk children received treatment in 2016. This Seminar describes the epidemiology, lifecycles, pathophysiology, clinical diagnosis, management, and public health control of soil-transmitted helminths. Previous work has questioned the effect of population-level deworming; however, it remains beyond doubt that treatment reduces the severe consequences of soil-transmitted helminthiasis. We highlight the need for refined diagnostic tools and effective control options to scale up public health interventions and improve clinical detection and management of these infections.
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Affiliation(s)
- Peter Mark Jourdan
- Schistosomiasis Control Initiative, Imperial College London, St Mary's Campus, London, UK; DEWORM3, Natural History Museum, London, UK; Norwegian Centre for Imported and Tropical Diseases, Department of Infectious Diseases, Oslo University Hospital, Ullevål, Oslo, Norway
| | - Poppy H L Lamberton
- Department of Infectious Disease Epidemiology, Imperial College London, St Mary's Campus, London, UK; Institute of Biodiversity, Animal Health and Comparative Medicine, The University of Glasgow, Glasgow, UK; Wellcome Centre for Molecular Parasitology, The University of Glasgow, Glasgow, UK.
| | - Alan Fenwick
- Schistosomiasis Control Initiative, Imperial College London, St Mary's Campus, London, UK
| | - David G Addiss
- The Task Force for Global Health, Decatur, GA, USA; Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, USA
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Jia TW, Melville S, Utzinger J, King CH, Zhou XN. Soil-transmitted helminth reinfection after drug treatment: a systematic review and meta-analysis. PLoS Negl Trop Dis 2012; 6:e1621. [PMID: 22590656 PMCID: PMC3348161 DOI: 10.1371/journal.pntd.0001621] [Citation(s) in RCA: 276] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 03/01/2012] [Indexed: 01/08/2023] Open
Abstract
Background Soil-transmitted helminth (STH) infections (i.e., Ascaris lumbricoides, hookworm, and Trichuris trichiura) affect more than a billion people. Preventive chemotherapy (i.e., repeated administration of anthelmintic drugs to at-risk populations), is the mainstay of control. This strategy, however, does not prevent reinfection. We performed a systematic review and meta-analysis to assess patterns and dynamics of STH reinfection after drug treatment. Methodology We systematically searched PubMed, ISI Web of Science, EMBASE, Cochrane Database of Systematic Reviews, China National Knowledge Infrastructure, WanFang Database, Chinese Scientific Journal Database, and Google Scholar. Information on study year, country, sample size, age of participants, diagnostic method, drug administration strategy, prevalence and intensity of infection pre- and posttreatment, cure and egg reduction rate, evaluation period posttreatment, and adherence was extracted. Pooled risk ratios from random-effects models were used to assess the risk of STH reinfection after treatment. Our protocol is available on PROSPERO, registration number: CRD42011001678. Principal Findings From 154 studies identified, 51 were included and 24 provided STH infection rates pre- and posttreatment, whereas 42 reported determinants of predisposition to reinfection. At 3, 6, and 12 months posttreatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16–43%), 68% (95% CI: 60–76%) and 94% (95% CI: 88–100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence were 36% (95% CI: 28–47%), 67% (95% CI: 42–100%), and 82% (95% CI: 62–100%), and for hookworm, 30% (95% CI: 26–34%), 55% (95% CI: 34–87%), and 57% (95% CI: 49–67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status. Conclusion STH reinfections occur rapidly after treatment, particularly for A. lumbricoides and T. trichiura. Hence, there is a need for frequent anthelmintic drug administrations to maximize the benefit of preventive chemotherapy. Integrated control approaches emphasizing health education and environmental sanitation are needed to interrupt transmission of STH. Infections with soil-transmitted helminths (the roundworm Ascaris lumbricoides, the whipworm Trichuris trichiura, and hookworm) affect over 1 billion people, particularly rural communities in the developing world. The global strategy to control soil-transmitted helminth infections is ‘preventive chemotherapy’, which means large-scale administration of anthelmintic drugs to at-risk populations. However, because reinfection occurs after treatment, ‘preventive chemotherapy’ must be repeated regularly. Our systematic review and meta-analysis found that at 3, 6, and 12 months after treatment, A. lumbricoides prevalence reached 26% (95% confidence interval (CI): 16–43%), 68% (95% CI: 60–76%) and 94% (95% CI: 88–100%) of pretreatment levels, respectively. For T. trichiura, respective reinfection prevalence at these time points were 36% (95% CI: 28–47%), 67% (95% CI: 42–100%), and 82% (95% CI: 62–100%); and for hookworm, 30% (95% CI: 26–34%), 55% (95% CI: 34–87%), and 57% (95% CI: 49–67%). Prevalence and intensity of reinfection were positively correlated with pretreatment infection status. Our results suggest a frequent anthelmintic drug administration to maximize the benefit of preventive chemotherapy. Moreover, an integrated control strategy, consisting of preventive chemotherapy combined with health education and environmental sanitation is needed to interrupt transmission of soil-transmitted helminths.
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Affiliation(s)
- Tie-Wu Jia
- Key Laboratory on Biology of Parasites and Vectors, MOH, WHO Collaborating Center on Malaria, Schistosomiasis and Filariasis, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China
- * E-mail: (T-WJ); (X-NZ)
| | - Sara Melville
- Hughes Hall College, Cambridge University, Cambridge, United Kingdom
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Xiao-Nong Zhou
- Key Laboratory on Biology of Parasites and Vectors, MOH, WHO Collaborating Center on Malaria, Schistosomiasis and Filariasis, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, People's Republic of China
- * E-mail: (T-WJ); (X-NZ)
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Cundill B, Alexander N, Bethony JM, Diemert D, Pullan RL, Brooker S. Rates and intensity of re-infection with human helminths after treatment and the influence of individual, household, and environmental factors in a Brazilian community. Parasitology 2011; 138:1406-16. [PMID: 21819640 PMCID: PMC3827741 DOI: 10.1017/s0031182011001132] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
This study quantifies the rate and intensity of re-infection with human hookworm and Schistosoma mansoni infection 12 months following successful treatment, and investigates the influence of socio-economic, geographical and environmental factors. A longitudinal study of 642 individuals aged over 5 years was conducted in Minas Gerais State, Brazil from June 2004 to March 2006. Risk factors were assessed using interval censored regression for the rate and negative binomial regression for intensity. The crude rate and intensity of hookworm re-infection was 0·21 per year (95% confidence interval (CI) 0·15-0·29) and 70·9 epg (95% CI 47·2-106·6). For S. mansoni the rate was 0·06 per year (95% CI 0·03-0·10) and intensity 6·51 epg (95% CI 3·82-11·11). Rate and intensity of re-infection with hookworm were highest among males and positively associated with previous infection status, absence of a toilet and house structure. Rate and intensity of S. mansoni re-infection were associated with previous infection status as well as geographical, environmental and socio-economic factors. The implications of findings for the design of anti-helminth vaccine trials are discussed.
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Affiliation(s)
- Bonnie Cundill
- London School of Hygiene and Tropical Medicine, London, UK.
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8
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Bourke CD, Maizels RM, Mutapi F. Acquired immune heterogeneity and its sources in human helminth infection. Parasitology 2011; 138:139-59. [PMID: 20946693 PMCID: PMC3021922 DOI: 10.1017/s0031182010001216] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 07/18/2010] [Accepted: 07/18/2010] [Indexed: 12/13/2022]
Abstract
Similarities in the immunobiology of different parasitic worm infections indicate that co-evolution of humans and helminths has shaped a common anti-helminth immune response. However, recent in vitro and immuno-epidemiological studies highlight fundamental differences and plasticity within host-helminth interactions. The 'trade-off' between immunity and immunopathology inherent in host immune responses occurs on a background of genetic polymorphism, variable exposure patterns and infection history. For the parasite, variation in life-cycle and antigen expression can influence the effector responses directed against them. This is particularly apparent when comparing gastrointestinal and tissue-dwelling helminths. Furthermore, insights into the impact of anti-helminthic treatment and co-infection on acquired immunity suggest that immune heterogeneity arises not from hosts and parasites in isolation, but also from the environment in which immune responses develop. Large-scale differences observed in the epidemiology of human helminthiases are a product of complex host-parasite-environment interactions which, given potential for exposure to parasite antigens in utero, can arise even before a parasite interacts with its human host. This review summarizes key differences identified in human acquired immune responses to nematode and trematode infections of public health importance and explores the factors contributing to these variations.
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Affiliation(s)
- C D Bourke
- Institute of Immunology and Infection Research, University of Edinburgh, Ashworth Laboratories, West Mains Road, Edinburgh EH93JT, UK.
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9
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King EM, Kim HT, Dang NT, Michael E, Drake L, Needham C, Haque R, Bundy DAP, Webster JP. Immuno-epidemiology of Ascaris lumbricoides infection in a high transmission community: antibody responses and their impact on current and future infection intensity. Parasite Immunol 2005; 27:89-96. [PMID: 15882235 DOI: 10.1111/j.1365-3024.2005.00753.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The role of the humoral immune system in human infection with Ascaris lumbricoides remains unclear. This study documents an epidemiological investigation in a highly endemic community in Vietnam, whereby serum antibody levels were assessed before treatment and after a 6-month reinfection period. These data were examined by correlation with infection status using an age-structured approach in an attempt to help shed light on the role of the humoral immune response. The first part of this study characterized levels of all serum antibody isotypes from the community in response to antigens of both adult and larval A. lumbricoides. Data were assessed in terms of their relation to host age and infection intensity with the aim to provide a broadly detailed account of immune responses to the parasite. In the second part, antibody responses to both life-stages of A. lumbricoides in serum samples collected before anthelmintic chemotherapy were analysed in relation to intensity of re-infection with the parasite 6 months following treatment. The results suggest that antibody responses may not confer protection from current infection or re-infection with A. lumbricoides and may not serve as reliable indicators of future infection intensity. Our results thereby lend support to the theory that immunity to A. lumbricoides may not be based on the humoral immune system.
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Affiliation(s)
- E-M King
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3FY, UK.
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10
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Hotez PJ. Pediatric geohelminth infections: Trichuriasis, ascariasis, and hookworm infections. ACTA ACUST UNITED AC 2000. [DOI: 10.1053/spid.2000.9637] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Needham CS, Lillywhite JE. Immunoepidemiology of intestinal helminthic infections. 2. Immunological correlates with patterns of Trichuris infection. Trans R Soc Trop Med Hyg 1994; 88:262-4. [PMID: 7974658 DOI: 10.1016/0035-9203(94)90071-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The significance of parasite-specific serum and secretory immunoglobulin (Ig) isotype responses as determinants of Trichuris trichiura infection intensity in endemic communities is discussed. Comparison of age-dependent isotype responses and the age profiles of infection intensity in 2 endemic communities with markedly different levels of T. trichiura transmission suggest that serum IgA responses may reflect the accumulated past experience of infection and thus may be relevant in acquired immunity to T. trichiura and contribute to the age-convexity of infection intensity in areas of intense transmission. Preliminary analysis of data from a second community-based study shows that parasite-specific secretory IgA in saliva increases with age and correlates negatively with infection intensity, suggesting that secretory IgA may also be implicated in acquired immunity to this gut-dwelling nematode.
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Affiliation(s)
- C S Needham
- Department of Biology, Imperial College of Science, Medicine and Technology, London, UK
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12
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Bradley M, Chandiwana SK, Bundy DA. The epidemiology and control of hookworm infection in the Burma Valley area of Zimbabwe. Trans R Soc Trop Med Hyg 1993; 87:145-7. [PMID: 8337712 DOI: 10.1016/0035-9203(93)90463-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
An integrated hookworm control programme, involving mass chemotherapy and improvements in public health, was conducted in the Burma Valley and Vumba areas of Zimbabwe between 1985 and 1990. Three sequential annual mass chemotherapy programmes were implemented. Infection status was monitored annually throughout. Initial observations indicated asymptotic age prevalence and intensity profiles, with peak infection levels in adults. Mass chemotherapy was shown to have immediate and medium term benefits for community health. Reinfection was slow to develop, and average intensity had not returned to pre-intervention levels 39 months after the cessation of chemotherapy. The results support the existence of age-dependency in reinfection. Despite a marked increase in the number of sanitation units, no relationship was found between latrine availability and reinfection intensity on individual farms. This result is consistent with observations that the effect of sanitation is slow to develop, and indicates that repeated anthelmintic intervention should be maintained until sanitation has an impact on transmission.
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Affiliation(s)
- M Bradley
- Blair Research Laboratory, Harare, Zimbabwe
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13
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Bundy DA, Medley GF. Immuno-epidemiology of human geohelminthiasis: ecological and immunological determinants of worm burden. Parasitology 1992; 104 Suppl:S105-19. [PMID: 1589298 DOI: 10.1017/s0031182000075284] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The morbidity and transmission dynamics of geohelminthiases are determined by the patterns of infection intensity in the community. Understanding the determinants of these patterns requires a combination of field, laboratory and theoretical study. Studies of age-specific reinfection, and of the phenomenon of predisposition, indicate that the major determinant of convex age-intensity profiles and of heterogeneity in infection intensity is the rate of establishment of infection, rather than the rate of adult worm mortality. The rate of establishment is, in turn, determined by exposure to, and protection from, infection. The evidence indicates that exposure, at least to the orally-transmitted geohelminths, varies with age and is highly heterogeneous between hosts. The immune response in geohelminthiasis is vigorous, parasite-specific, heterogeneous between hosts, and both age and infection dose dependent, but has yet to be convincingly shown to be protective. Since the immune response it itself a function of exposure, unravelling the interaction between ecology and immunology as determinants of geohelminth worm burden will require simultaneous assessment of both processes via immunoepidemiological study.
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Affiliation(s)
- D A Bundy
- Wellcome Trust Research Centre for Parasitic Infections, Imperial College, London
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Chan L, Kan SP, Bundy DA. The effect of repeated chemotherapy on age-related predisposition to Ascaris lumbricoides and Trichuris trichiura. Parasitology 1992; 104 ( Pt 2):371-7. [PMID: 1594301 DOI: 10.1017/s0031182000061837] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study examines the persistence of predisposition to Ascaris lumbricoides and Trichuris trichiura during repeated chemotherapy in an urban community in Kuala Lumpur, Malaysia. Significant predisposition was observed over 2 periods of reinfection with and without age-standardization of data. Analysis of different age groups indicated that predisposition was most strongly detectable in the younger age classes. The intensities of infection with both parasites were strongly correlated at each cycle of intervention, suggesting that individuals were similarly predisposed to both species.
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Affiliation(s)
- L Chan
- Department of Biology, Imperial College, London, UK
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15
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Butterworth AE, Sturrock RF, Ouma JH, Mbugua GG, Fulford AJ, Kariuki HC, Koech D. Comparison of different chemotherapy strategies against Schistosoma mansoni in Machakos District, Kenya: effects on human infection and morbidity. Parasitology 1991; 103 Pt 3:339-55. [PMID: 1780171 DOI: 10.1017/s0031182000059850] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A comparison was made of the long-term impact of different methods of administration of chemotherapy (oxamniquine, 30 mg/kg in divided doses; or praziquantel, 40 mg/kg) on prevalence and intensity of Schistosoma mansoni infection in four areas in Kangundo Location, Machakos District, Kenya. In Area A, treatment was offered in October 1983 and again in April 1985 to all infected individuals. In Area H, treatment was offered in April 1985 to individuals excreting greater than or equal to 100 eggs per gram (epg) of faeces. In Area S, treatment was offered in April 1985 to all infected school children, within the framework of the primary schools. In the witness area, Area W, treatment was given in April 1985, for ethical reasons, to a small number of individuals excreting greater than or equal to 800 epg. Prevalence and intensities of infection were subsequently monitored at yearly intervals for three complete post-treatment years. In the Area S schools, clinical examination was also carried out at yearly intervals. Treatment of all infected individuals on two occasions (Area A) was the most effective and long-lasting way of reducing prevalence and intensity of infection. In this area, however, some earlier interventions had been carried out and pre-treatment intensities were lower than in the other areas. Treatment only of infected schoolchildren (Area S) also had a marked and prolonged effect, comparable to or better than treatment of individuals with heavy infections (Area H). Treatment of infected schoolchildren also caused a persistent reduction in the prevalence of hepatomegaly, and there was suggestive evidence from intensities of infection in community stool surveys (but not from incidence rates) of an effect on transmission. In all study areas, reinfection was most rapid and most intense among children. These findings are discussed in the light of theoretical considerations and of results from other studies, both on schistosomiasis and on intestinal helminths. We conclude that, in areas of low morbidity such as Kangundo, chemotherapy of schoolchildren only, at intervals of up to 3 years, is a satisfactory way of producing a long-term reduction in both intensity of infection and morbidity.
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Bradley M, Chandiwana SK. Age-dependency in predisposition to hookworm infection in the Burma valley area of Zimbabwe. Trans R Soc Trop Med Hyg 1990; 84:826-8. [PMID: 2136254 DOI: 10.1016/0035-9203(90)90096-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We examined hookworm re-infection intensities (measured as faecal egg count by the Kato technique) following anthelmintic treatment of farm workers resident on 15 large-scale commercial farms in Zimbabwe. All individuals examined were treated with albendazole (400 mg). Hookworm reinfection intensities of individuals examined, treated and reexamined were compared with the intensities of infection before treatment. Adults had higher than average infection intensities both before and after reinfection. Predisposition to hookworm infection was marked in adults, and absent from younger, less heavily infected hosts. The observations suggest that acquired immunity is unlikely to be an important determinant of hookworm infection and that behaviour may play a major role in determining the observed infection patterns in this community.
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Affiliation(s)
- M Bradley
- Blair Research Laboratory, Harare, Zimbabwe
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Affiliation(s)
- D A Bundy
- Department of Pure and Applied Biology, Imperial College of Science, Technology and Medicine, London, UK
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18
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Bundy DA. Population ecology of intestinal helminth infections in human communities. Philos Trans R Soc Lond B Biol Sci 1988; 321:405-20. [PMID: 2907151 DOI: 10.1098/rstb.1988.0100] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The distribution of worm burdens in human populations is a major determinant of both the dynamics of transmission and the level of community morbidity. The distribution exhibits convexity with host age, which appears to correlate with exposure in the young age-classes but not in adults, and may be evidence for the development of an acquired immune response. The distribution between individuals is typically overdispersed. Individuals are predisposed to high (or low) intensity of infection and to a correspondingly high (or low) rate of acquisition of infection. A major epidemiological question is whether this reflects individual differences in environmental exposure or susceptibility. Environmental studies that have observed clustering of intense infection in particular households are supportive of either mechanism. Individual host behaviours that predispose to infection have an overdispersed distribution and may alone, or as compounding factors, generate the observed distribution of infection intensity. Factors such as host nutrition and physiology may modify host immune-responsiveness and hence susceptibility. Preliminary evidence suggests correlates between infection intensity and HLA class II antigens, and tentatively implies a genetic factor in susceptibility. These findings suggest that further understanding of the relative importance of environmental factors and resistance to the acquisition of intense infection is dependent upon a multidisciplinary approach to epidemiological field study.
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Affiliation(s)
- D A Bundy
- Department of Pure and Applied Biology, Imperial College, London, U.K
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