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Lupi O, Downing C, Lee M, Pino L, Bravo F, Giglio P, Sethi A, Klaus S, Sangueza OP, Fuller C, Mendoza N, Ladizinski B, Woc-Colburn L, Tyring SK. Mucocutaneous manifestations of helminth infections: Nematodes. J Am Acad Dermatol 2016; 73:929-44; quiz 945-6. [PMID: 26568337 DOI: 10.1016/j.jaad.2014.11.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/06/2014] [Accepted: 11/17/2014] [Indexed: 11/30/2022]
Abstract
In the 21st century, despite increased globalization through international travel for business, medical volunteerism, pleasure, and immigration/refugees into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on the cutaneous manifestations of helminth infections and is divided into 2 parts: part I focuses on nematode infections, and part II focuses on trematode and cestode infections. This review highlights the clinical manifestations, transmission, diagnosis, and treatment of helminth infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.
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Affiliation(s)
- Omar Lupi
- Federal University of the State of Rio de Janeiro and Policlinica Geral do Rio de Janeiro, Rio de Janerio, Brazil
| | - Christopher Downing
- Department of Dermatology, University of Texas Health Science Center, Houston, Texas.
| | - Michael Lee
- Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Livia Pino
- Federal University of the State of Rio de Janeiro and Policlinica Geral do Rio de Janeiro, Rio de Janerio, Brazil
| | - Francisco Bravo
- Instituto de Medicina Tropical Alexander von Humboldt, Lima, Peru; Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Aisha Sethi
- Section of Infectious Diseases and Global Health, Department of Dermatology, University of Chicago, Chicago, Illinois
| | - Sidney Klaus
- Department of Dermatology, Dartmouth School of Medicine, Hanover, New Hampshire
| | - Omar P Sangueza
- Department of Pathology, Wake Forest School of Medicine, Winston-Salem, North Carolina; Department of Dermatology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Claire Fuller
- International Foundation for Dermatology and Consultant, Chelsea and Westminster Hospital, London, United Kingdom
| | - Natalia Mendoza
- Department of Dermatology, University of Texas Health Science Center, Houston, Texas
| | - Barry Ladizinski
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Laila Woc-Colburn
- National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas
| | - Stephen K Tyring
- Center for Clinical Studies, Houston, Texas; Department of Dermatology, University of Texas Health Science Center, Houston, Texas
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Impact of Six Years Community Directed Treatment with Ivermectin in the Control of Onchocerciasis, Western Ethiopia. PLoS One 2016; 11:e0141029. [PMID: 26942910 PMCID: PMC4778937 DOI: 10.1371/journal.pone.0141029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 10/01/2015] [Indexed: 11/19/2022] Open
Abstract
Background The African Program for Onchocerciais Control (APOC) with a main strategy of community directed treatment with ivermectin (CDTI) was established with the aim of eliminating Onchocerciasis as a disease of public health and socio-economic importance. The study area was a hyper endemic area just before the implementation of CDTI. It has been implemented for six years in this district but yet not been evaluated. So, the objective of this study was to evaluate the impact of six years CDTI on parasitological and clinical indices of Onchocerciasis Methods This study employed a pre-post impact evaluation design. The minimum sample size for this study was 1318; the respondents were selected by multi-stage sampling technique. Data on socio-demographic characteristics using a semi-structured questionnaire, clinical examination for skin signs and symptoms of Onchocerciasis and two bloodless skin snips from each side of the gluteal fold were taken from the entire study participants. SPSS version 16.0 and Medcalc version 12.2.1.0 were used for analysis. Result The microfilaridermia reduced from the pre-intervention value of 74.8% to 40.7%, indicating a 45.6% reduction, mean intensity from 32.1(SD = 61.5) mf/mg skin snip to 18.7(SD = 28.7)indicating 41.75% reduction, CMFL from 19.6 mf/mg skin snip to 4.7 indicating 76% reduction. The result also showed that microfilaridermia and mean intensity decreased as the number of treatment taken increased. Pruritis, leopard skin, onchocercomata and hanging groin reduced by 54.4%, 61.3%, 77.7% and 88.5% respectively. Conclusions The implementation of CDTI significantly reduced the parasitological and clinical indices of Onchocerciasis, so, efforts should be made to improve the annual treatment coverage and sustainability of CDTI to drastically reduce the micro filarial load to the level the disease would no longer be a public health problem.
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Golden A, Stevens EJ, Yokobe L, Faulx D, Kalnoky M, Peck R, Valdez M, Steel C, Karabou P, Banla M, Soboslay PT, Adade K, Tekle AH, Cama VA, Fischer PU, Nutman TB, Unnasch TR, de los Santos T, Domingo GJ. A Recombinant Positive Control for Serology Diagnostic Tests Supporting Elimination of Onchocerca volvulus. PLoS Negl Trop Dis 2016; 10:e0004292. [PMID: 26745374 PMCID: PMC4706346 DOI: 10.1371/journal.pntd.0004292] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 11/19/2015] [Indexed: 11/24/2022] Open
Abstract
Background Serological assays for human IgG4 to the Onchocerca volvulus antigen Ov16 have been used to confirm elimination of onchocerciasis in much of the Americas and parts of Africa. A standardized source of positive control antibody (human anti-Ov16 IgG4) will ensure the quality of surveillance data using these tests. Methodology/Principal Findings A recombinant human IgG4 antibody to Ov16 was identified by screening against a synthetic human Fab phage display library and converted into human IgG4. This antibody was developed into different positive control formulations for enzyme-linked immunosorbent assay (ELISA) and rapid diagnostic test (RDT) platforms. Variation in ELISA results and utility as a positive control of the antibody were assessed from multiple laboratories. Temperature and humidity conditions were collected across seven surveillance activities from 2011–2014 to inform stability requirements for RDTs and positive controls. The feasibility of the dried positive control for RDT was evaluated during onchocerciasis surveillance activity in Togo, in 2014. When the anti-Ov16 IgG4 antibody was used as a standard dilution in horseradish peroxidase (HRP) and alkaline phosphatase (AP) ELISAs, the detection limits were approximately 1ng/mL by HRP ELISA and 10ng/mL by AP ELISA. Positive control dilutions and spiked dried blood spots (DBS) produced similar ELISA results. Used as a simple plate normalization control, the positive control antibody may improve ELISA data comparison in the context of inter-laboratory variation. The aggregate temperature and humidity monitor data informed temperature parameters under which the dried positive control was tested and are applicable inputs for testing of diagnostics tools intended for sub-Saharan Africa. As a packaged positive control for Ov16 RDTs, stability of the antibody was demonstrated for over six months at relevant temperatures in the laboratory and for over 15 weeks under field conditions. Conclusions The recombinant human anti-Ov16 IgG4 antibody-based positive control will benefit inter-laboratory validation of ELISA assays and serve as quality control (QC) reagents for Ov16 RDTs at different points of the supply chain from manufacturer to field use. Serological markers such as antibody responses to pathogen-specific antigens are used to inform disease epidemiology in many elimination programs. A major challenge with program-scale serological testing, and with any diagnostic test validation, is access to consistent and unlimited control reagents with which to provide assay QC and facilitate data consolidation. In the context of disease elimination, clinical positive sera will be particularly difficult to source and use as routine, inter-laboratory reagents. This study reports on a recombinant antibody specific against a key serological marker for onchocerciasis: its selection, testing, and incorporation into protocols across relevant immunoassay platforms. We have demonstrated it is a viable reagent for integration into QC and QA protocols to support long-term serological testing for onchocerciasis to support disease elimination efforts. This approach should be generalizable to other diagnostic tools supporting programs to achieve the 2020 goals of the London Declaration on Neglected Tropical Diseases.
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Affiliation(s)
- Allison Golden
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
- * E-mail:
| | - Eric J. Stevens
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Lindsay Yokobe
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Dunia Faulx
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Michael Kalnoky
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Roger Peck
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Melissa Valdez
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Cathy Steel
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - Méba Banla
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
| | - Peter T. Soboslay
- Onchocerciasis Reference Laboratory, National Institute of Hygiene, Sokodé, Togo
- Institute of Tropical Medicine, University Clinics of Tübingen, Tübingen, Germany
| | - Kangi Adade
- National Onchocerciasis Control Programme, Kara, Togo
| | - Afework H. Tekle
- African Programme for Onchocerciasis Control, World Health Organization, Ouagadougou, Burkina Faso
| | - Vitaliano A. Cama
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Peter U. Fischer
- Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Thomas B. Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Thomas R. Unnasch
- Global Health Infectious Disease Research Program, Department of Global Health, University of South Florida, Tampa, Florida, United States of America
| | - Tala de los Santos
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
| | - Gonzalo J. Domingo
- Diagnostics Global Program, PATH, Seattle, Washington, United States of America
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Basáñez M, Walker M, Turner H, Coffeng L, de Vlas S, Stolk W. River Blindness: Mathematical Models for Control and Elimination. ADVANCES IN PARASITOLOGY 2016; 94:247-341. [PMID: 27756456 DOI: 10.1016/bs.apar.2016.08.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Human onchocerciasis (river blindness) is one of the few neglected tropical diseases (NTDs) whose control strategies have been informed by mathematical modelling. With the change in focus from elimination of the disease burden to elimination of Onchocerca volvulus, much remains to be done to refine, calibrate and validate existing models. Under the impetus of the NTD Modelling Consortium, the teams that developed EPIONCHO and ONCHOSIM have joined forces to compare and improve these frameworks to better assist ongoing elimination efforts. We review their current versions and describe how they are being used to address two key questions: (1) where can onchocerciasis be eliminated with current intervention strategies by 2020/2025? and (2) what alternative/complementary strategies could help to accelerate elimination where (1) cannot be achieved? The control and elimination of onchocerciasis from the African continent is at a crucial crossroad. The African Programme for Onchocerciasis Control closed at the end of 2015, and although a new platform for support and integration of NTD control has been launched, the disease will have to compete with a myriad of other national health priorities at a pivotal time in the road to elimination. However, never before had onchocerciasis control a better arsenal of intervention strategies as well as diagnostics. It is, therefore, timely to present two models of different geneses and modelling traditions as they come together to produce robust decision-support tools. We start by describing the structural and parametric assumptions of EPIONCHO and ONCHOSIM; we continue by summarizing the modelling of current treatment strategies with annual (or biannual) mass ivermectin distribution and introduce a number of alternative strategies, including other microfilaricidal therapies (such as moxidectin), macrofilaricidal (anti-wolbachial) treatments, focal vector control and the possibility of an onchocerciasis vaccine. We conclude by discussing challenges, opportunities and future directions.
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O’Hanlon SJ, Slater HC, Cheke RA, Boatin BA, Coffeng LE, Pion SDS, Boussinesq M, Zouré HGM, Stolk WA, Basáñez MG. Model-Based Geostatistical Mapping of the Prevalence of Onchocerca volvulus in West Africa. PLoS Negl Trop Dis 2016; 10:e0004328. [PMID: 26771545 PMCID: PMC4714852 DOI: 10.1371/journal.pntd.0004328] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/04/2015] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The initial endemicity (pre-control prevalence) of onchocerciasis has been shown to be an important determinant of the feasibility of elimination by mass ivermectin distribution. We present the first geostatistical map of microfilarial prevalence in the former Onchocerciasis Control Programme in West Africa (OCP) before commencement of antivectorial and antiparasitic interventions. METHODS AND FINDINGS Pre-control microfilarial prevalence data from 737 villages across the 11 constituent countries in the OCP epidemiological database were used as ground-truth data. These 737 data points, plus a set of statistically selected environmental covariates, were used in a Bayesian model-based geostatistical (B-MBG) approach to generate a continuous surface (at pixel resolution of 5 km x 5km) of microfilarial prevalence in West Africa prior to the commencement of the OCP. Uncertainty in model predictions was measured using a suite of validation statistics, performed on bootstrap samples of held-out validation data. The mean Pearson's correlation between observed and estimated prevalence at validation locations was 0.693; the mean prediction error (average difference between observed and estimated values) was 0.77%, and the mean absolute prediction error (average magnitude of difference between observed and estimated values) was 12.2%. Within OCP boundaries, 17.8 million people were deemed to have been at risk, 7.55 million to have been infected, and mean microfilarial prevalence to have been 45% (range: 2-90%) in 1975. CONCLUSIONS AND SIGNIFICANCE This is the first map of initial onchocerciasis prevalence in West Africa using B-MBG. Important environmental predictors of infection prevalence were identified and used in a model out-performing those without spatial random effects or environmental covariates. Results may be compared with recent epidemiological mapping efforts to find areas of persisting transmission. These methods may be extended to areas where data are sparse, and may be used to help inform the feasibility of elimination with current and novel tools.
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Affiliation(s)
- Simon J. O’Hanlon
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s Campus), Imperial College London, London, United Kingdom
| | - Hannah C. Slater
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s Campus), Imperial College London, London, United Kingdom
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Robert A. Cheke
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s Campus), Imperial College London, London, United Kingdom
- Natural Resources Institute, University of Greenwich at Medway, Chatham, Kent, United Kingdom
| | - Boakye A. Boatin
- Lymphatic Filariasis Support Centre, Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sébastien D. S. Pion
- UMI 233, Institut de Recherche pour le Développement (IRD) and University of Montpellier 1, Montpellier, France
| | - Michel Boussinesq
- UMI 233, Institut de Recherche pour le Développement (IRD) and University of Montpellier 1, Montpellier, France
| | - Honorat G. M. Zouré
- African Programme for Onchocerciasis Control (APOC), World Health Organization (WHO), Ouagadougou, Burkina Faso
| | - Wilma A. Stolk
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary’s Campus), Imperial College London, London, United Kingdom
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
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Cheke RA, Basáñez MG, Perry M, White MT, Garms R, Obuobie E, Lamberton PHL, Young S, Osei-Atweneboana MY, Intsiful J, Shen M, Boakye DA, Wilson MD. Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2013.0559. [PMID: 25688018 PMCID: PMC4342963 DOI: 10.1098/rstb.2013.0559] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25°C, the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29°C and 34°C, about 3°C and 7°C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 29°C and of savannah flies (Ghana) at 30°C. Small temperature increases (less than 2°C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 33°C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13–41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions.
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Affiliation(s)
- Robert A Cheke
- Agriculture, Health and Environment Department, Natural Resources Institute, University of Greenwich at Medway, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Malorie Perry
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Michael T White
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Rolf Garms
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, Hamburg 20359, Germany
| | - Emmanuel Obuobie
- Water Research Institute, Council for Scientific and Industrial Research, PO Box M32, Accra, Ghana
| | - Poppy H L Lamberton
- Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Stephen Young
- Agriculture, Health and Environment Department, Natural Resources Institute, University of Greenwich at Medway, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK
| | - Mike Y Osei-Atweneboana
- Water Research Institute, Council for Scientific and Industrial Research, PO Box M32, Accra, Ghana
| | - Joseph Intsiful
- Regional Institute for Population Studies, University of Ghana, PO Box LG 97, Legon, Accra, Ghana
| | - Mingwang Shen
- Department of Applied Mathematics, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
| | - Michael D Wilson
- Noguchi Memorial Institute for Medical Research, University of Ghana, PO Box LG 581, Legon, Accra, Ghana
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Golding N, Wilson AL, Moyes CL, Cano J, Pigott DM, Velayudhan R, Brooker SJ, Smith DL, Hay SI, Lindsay SW. Integrating vector control across diseases. BMC Med 2015; 13:249. [PMID: 26423147 PMCID: PMC4590270 DOI: 10.1186/s12916-015-0491-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/17/2015] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Vector-borne diseases cause a significant proportion of the overall burden of disease across the globe, accounting for over 10 % of the burden of infectious diseases. Despite the availability of effective interventions for many of these diseases, a lack of resources prevents their effective control. Many existing vector control interventions are known to be effective against multiple diseases, so combining vector control programmes to simultaneously tackle several diseases could offer more cost-effective and therefore sustainable disease reductions. DISCUSSION The highly successful cross-disease integration of vaccine and mass drug administration programmes in low-resource settings acts a precedent for cross-disease vector control. Whilst deliberate implementation of vector control programmes across multiple diseases has yet to be trialled on a large scale, a number of examples of 'accidental' cross-disease vector control suggest the potential of such an approach. Combining contemporary high-resolution global maps of the major vector-borne pathogens enables us to quantify overlap in their distributions and to estimate the populations jointly at risk of multiple diseases. Such an analysis shows that over 80 % of the global population live in regions of the world at risk from one vector-borne disease, and more than half the world's population live in areas where at least two different vector-borne diseases pose a threat to health. Combining information on co-endemicity with an assessment of the overlap of vector control methods effective against these diseases allows us to highlight opportunities for such integration. Malaria, leishmaniasis, lymphatic filariasis, and dengue are prime candidates for combined vector control. All four of these diseases overlap considerably in their distributions and there is a growing body of evidence for the effectiveness of insecticide-treated nets, screens, and curtains for controlling all of their vectors. The real-world effectiveness of cross-disease vector control programmes can only be evaluated by large-scale trials, but there is clear evidence of the potential of such an approach to enable greater overall health benefit using the limited funds available.
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Affiliation(s)
- Nick Golding
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
| | - Anne L Wilson
- School of Biological and Biomedical Sciences, Durham University, Durham, DH1 3LE, UK.
| | - Catherine L Moyes
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
| | - Jorge Cano
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
| | - David M Pigott
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
| | - Raman Velayudhan
- Department of Control of Neglected Tropical Diseases, World Health Organization, 1211, Geneva, Switzerland.
| | - Simon J Brooker
- Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
| | - David L Smith
- Institute of Health Metrics and Evaluation, University of Washington, Seattle, WA, 98121, USA. .,Department of Zoology, University of Oxford, Oxford, OX1 3PS, UK. .,Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Simon I Hay
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK. .,Institute of Health Metrics and Evaluation, University of Washington, Seattle, WA, 98121, USA. .,Fogarty International Center, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Steve W Lindsay
- School of Biological and Biomedical Sciences, Durham University, Durham, DH1 3LE, UK.
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Expanding the MDx toolbox for filarial diagnosis and surveillance. Trends Parasitol 2015; 31:391-400. [DOI: 10.1016/j.pt.2015.04.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/10/2015] [Accepted: 04/13/2015] [Indexed: 11/17/2022]
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Chen T, Moon K, deMello DE, Feiz-Erfan I, Theodore N, Bhardwaj RD. Case report of an epidural cervical Onchocerca lupi infection in a 13-year-old boy. J Neurosurg Pediatr 2015; 16:217-21. [PMID: 25932778 DOI: 10.3171/2014.12.peds14462] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A 13-year-old boy presented with fever and neck pain and stiffness, which was initially misdiagnosed as culture-negative meningitis. Magnetic resonance images of the brain and cervical spine demonstrated what appeared to be an intradural extramedullary mass at the C1-3 level, resulting in moderate cord compression, and a Chiari Type I malformation. The patient underwent a suboccipital craniectomy and a C1-3 laminectomy with intradural exploration for excisional biopsy and resection. The lesion containing the parasite was extradural, extending laterally through the C2-3 foramina. Inflammatory tissue secondary to Onchocerca lupi infection was identified, and treatment with steroids and doxycycline was initiated. At the 6-month follow-up, the patient remained asymptomatic, with MR images demonstrating a significant reduction in lesional size. However, 10 weeks postoperatively, the infection recurred, necessitating a second operation. The patient was treated with an additional course of doxycycline and is currently maintained on ivermectin therapy. This is the second reported case of cervical O. lupi infection in a human. In the authors' experience, oral doxycycline alone was insufficient in controlling the disease, and the addition of ivermectin therapy was necessary.
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Affiliation(s)
- Tsinsue Chen
- Department of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center
| | - Karam Moon
- Department of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center
| | - Daphne E deMello
- Department of Pathology and Laboratory Medicine, Phoenix Children's Hospital
| | - Iman Feiz-Erfan
- The University of Arizona, College of Medicine-Phoenix; and.,Division of Neurosurgery, Maricopa Medical Center, Phoenix, Arizona
| | - Nicholas Theodore
- Department of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center
| | - Ratan D Bhardwaj
- Division of Neurological Surgery, Barrow Neurological Institute, Phoenix Children's Hospital
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O'Neill M, Geary JF, Agnew DW, Mackenzie CD, Geary TG. In vitro flubendazole-induced damage to vital tissues in adult females of the filarial nematode Brugia malayi. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2015; 5:135-40. [PMID: 26288741 PMCID: PMC4534755 DOI: 10.1016/j.ijpddr.2015.06.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 11/26/2022]
Abstract
The use of a microfilaricidal drug for the control of onchocerciasis and lymphatic filariasis necessitates prolonged yearly dosing. Prospects for elimination or eradication of these diseases would be enhanced by availability of a macrofilaricidal drug. Flubendazole (FLBZ), a benzimidazole anthelmintic, is an appealing candidate macrofilaricide. FLBZ has demonstrated profound and potent macrofilaricidal effects in a number of experimental filarial rodent models and one human trial. Unfortunately, FLBZ was deemed unsatisfactory for use in mass drug administration (MDA) campaigns due to its markedly limited oral bioavailability. However, a new formulation that provided sufficient bioavailability following oral administration could render FLBZ an effective treatment for onchocerciasis and LF. This study characterized the effects of FLBZ and its reduced metabolite (FLBZ-R) on filarial nematodes in vitro to determine the exposure profile which results in demonstrable damage. Adult female Brugia malayi were exposed to varying concentrations of FLBZ or FLBZ-R (100 nM–10 μM) for up to five days, after which worms were fixed for histology. Morphological damage following exposure to FLBZ was observed prominently in the hypodermis and developing embryos at concentrations as low as 100 nM following 24 h exposure. The results indicate that damage to tissues required for reproduction and survival can be achieved at pharmacologically relevant concentrations. Detrimental effects observed in tissues required for development and survival. Damage occurs at concentrations ≥100 nM. Hypodermal and embryonic tissues exhibited the most severe damage. Oocytes and early morula are the most affected embryonic tissues.
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Affiliation(s)
- Maeghan O'Neill
- Institute of Parasitology and Centre for Host-Parasite Interactions, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - James F Geary
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Dalen W Agnew
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Charles D Mackenzie
- Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, USA
| | - Timothy G Geary
- Institute of Parasitology and Centre for Host-Parasite Interactions, McGill University, Ste-Anne-de-Bellevue, QC H9X 3V9, Canada
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Dana D, Debalke S, Mekonnen Z, Kassahun W, Suleman S, Getahun K, Yewhalaw D. A community-based cross-sectional study of the epidemiology of onchocerciasis in unmapped villages for community directed treatment with ivermectin in Jimma Zone, southwestern Ethiopia. BMC Public Health 2015; 15:595. [PMID: 26130117 PMCID: PMC4486700 DOI: 10.1186/s12889-015-1888-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 05/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human onchocerciasis is a neglected tropical parasitic disease caused by Onchocerca volvulus (O. volvulus) that may result in devastating skin and eye morbidity. Even though the disease is targeted for elimination, there was little or no information on the level of onchocerciasis endemicity for implementation of community directed treatment with ivermectin (CDTI) in the current study area. Thus, this study aimed at investigating the epidemiology of onchocerciasis and the level of awareness towards the disease among communities living close to CDTI area, Jimma Zone, southwestern Ethiopia. METHODS A community based cross-sectional study was conducted from April 23 to May 22, 2012. Data on socio-demographic characteristics, knowledge, attitude and practice towards onchocerciasis were collected using semi-structured questionnaires. Clinical examination was undertaken for onchocercal skin diseases by experienced health professionals. Moreover, two skin snip samples were collected from the right and left gluteal folds. Study participants found positive for O. volvulus infection during the study were treated individually with standard dose of ivermectin as per WHO guideline. RESULTS The overall prevalence of O. volvulus infection was 22.5 % while the prevalence of onchocercal skin diseases was 29.8 %. The community microfilarial (mf) load was 5.70 mf per skin snip. Age, sex, educational status, occupation and duration of stay in the villages showed significant association with onchocerciasis (P < 0.05). But sex (OR = 0.565, 95 % CI = 0.335, 0.952), educational status (OR = 0.545, 95 % CI = 0.310, 0.958) and duration of stay in the village (OR = 5.933, 95 % CI = 1.017, 34.626) were the independent predictors for O. volvulus infection. Three hundred eighty eight (88.2 %) of the study participants reported that they didn't know about onchocerciasis. CONCLUSIONS There was moderate prevalence of onchocercal infection and onchocercial skin diseases (OSD) in the study area. Result of this study may suggest that the endemicity level of onchocerciasis in the study area was mesoendemic. Hence, intervention using ivermectin treatment should be implemented to reduce the burden of onchocerciasis. Since the majorities of the population had poor knowledge, attitude and practice towards onchocerciasis, inclusion of health education in the intervention package is crucial.
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Affiliation(s)
- Daniel Dana
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Serkadis Debalke
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Zeleke Mekonnen
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Wondwossen Kassahun
- Department of Epidemiology and Biostatistics, College of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Sultan Suleman
- Department of Pharmacy, College of Health Sciences, Jimma University, Jimma, Ethiopia.
| | - Kefelegn Getahun
- Department of Geography and Environmental Science, College of Social Sciences, Jimma University, Jimma, Ethiopia.
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia.
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Rapid Point-of-Contact Tool for Mapping and Integrated Surveillance of Wuchereria bancrofti and Onchocerca volvulus Infection. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:896-901. [PMID: 26018537 DOI: 10.1128/cvi.00227-15] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/20/2015] [Indexed: 11/20/2022]
Abstract
Elimination programs for Wuchereria bancrofti and Onchocerca volvulus are in critical need of sensitive, specific, and point-of-contact (POC) tools that can be used for surveillance years beyond cessation of mass drug administration when infection intensities are low. Previously, Wb123 and Ov16 were identified individually as potential filarial antigens for an antibody-based POC test. The present study compares single-antigen Wb123- and Ov16-based POC tests with an integrated configuration to detect antibodies to Wb123 and Ov16 simultaneously. Wb123 and Ov16 isolates were striped onto lateral flow strips containing anti-IgG4. Sera from W. bancrofti-, O. volvulus-, and other helminth-infected or -uninfected individuals were added to the strips with buffer. Strips were read for the appearance of a positive or negative test line for both antigens at 20 min and following drying. Sensitivity, specificity, and predictive values were calculated for the single-antigen and biplex strips. Single and biplex lateral flow strips showed nearly identical results, with >90% sensitivity for Ov16 and >92% sensitivity for Wb123. Overall specificities for the single and biplex tests were 98% and 96% for Ov16 and Wb123, respectively. Biplex tests performed as well as the single-antigen tests regardless of the intensity of patient IgG4 response. The high sensitivity and specificity make these new biplex tests extremely useful for POC long-term surveillance following mass drug administration in Africa that should reduce time and cost in areas where bancroftian filariasis and onchocerciasis are coendemic.
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D'Ambrosio MV, Bakalar M, Bennuru S, Reber C, Skandarajah A, Nilsson L, Switz N, Kamgno J, Pion S, Boussinesq M, Nutman TB, Fletcher DA. Point-of-care quantification of blood-borne filarial parasites with a mobile phone microscope. Sci Transl Med 2015; 7:286re4. [PMID: 25947164 PMCID: PMC11005326 DOI: 10.1126/scitranslmed.aaa3480] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Parasitic helminths cause debilitating diseases that affect millions of people in primarily low-resource settings. Efforts to eliminate onchocerciasis and lymphatic filariasis in Central Africa through mass drug administration have been suspended because of ivermectin-associated serious adverse events, including death, in patients infected with the filarial parasite Loa loa. To safely administer ivermectin for onchocerciasis or lymphatic filariasis in regions co-endemic with L. loa, a strategy termed "test and (not) treat" has been proposed whereby those with high levels of L. loa microfilariae (>30,000/ml) that put them at risk for life-threatening serious adverse events are identified and excluded from mass drug administration. To enable this, we developed a mobile phone-based video microscope that automatically quantifies L. loa microfilariae in whole blood loaded directly into a small glass capillary from a fingerprick without the need for conventional sample preparation or staining. This point-of-care device automatically captures and analyzes videos of microfilarial motion in whole blood using motorized sample scanning and onboard motion detection, minimizing input from health care workers and providing a quantification of microfilariae per milliliter of whole blood in under 2 min. To validate performance and usability of the mobile phone microscope, we tested 33 potentially Loa-infected patients in Cameroon and confirmed that automated counts correlated with manual thick smear counts (94% specificity; 100% sensitivity). Use of this technology to exclude patients from ivermectin-based treatment at the point of care in Loa-endemic regions would allow resumption/expansion of mass drug administration programs for onchocerciasis and lymphatic filariasis in Central Africa.
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Affiliation(s)
- Michael V D'Ambrosio
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA
| | - Matthew Bakalar
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA
| | - Sasisekhar Bennuru
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Clay Reber
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA
| | - Arunan Skandarajah
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA
| | - Lina Nilsson
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA
| | - Neil Switz
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA. Biophysics Graduate Group, UC Berkeley, Berkeley, CA 94720, USA
| | - Joseph Kamgno
- Center for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon. Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
| | - Sébastien Pion
- Center for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon. UMI 233, Institut de Recherche pour le Développement and University of Montpellier, Montpellier, France
| | - Michel Boussinesq
- UMI 233, Institut de Recherche pour le Développement and University of Montpellier, Montpellier, France
| | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA.
| | - Daniel A Fletcher
- Department of Bioengineering, University of California (UC), Berkeley, Berkeley, CA 94720, USA. Biophysics Graduate Group, UC Berkeley, Berkeley, CA 94720, USA.
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Debrah AY, Specht S, Klarmann-Schulz U, Batsa L, Mand S, Marfo-Debrekyei Y, Fimmers R, Dubben B, Kwarteng A, Osei-Atweneboana M, Boakye D, Ricchiuto A, Büttner M, Adjei O, Mackenzie CD, Hoerauf A. Doxycycline Leads to Sterility and Enhanced Killing of Female Onchocerca volvulus Worms in an Area With Persistent Microfilaridermia After Repeated Ivermectin Treatment: A Randomized, Placebo-Controlled, Double-Blind Trial. Clin Infect Dis 2015; 61:517-26. [PMID: 25948064 PMCID: PMC4518165 DOI: 10.1093/cid/civ363] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 03/23/2015] [Indexed: 11/23/2022] Open
Abstract
Sub-optimal responses to ivermectin (IVM) have emerged. Targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline is effective in clearing microfilariae in onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Background. Ivermectin (IVM) has been the drug of choice for the treatment of onchocerciasis. However, there have been reports of persistent microfilaridermia in individuals from an endemic area in Ghana after many rounds of IVM, raising concerns of suboptimal response or even the emergence of drug resistance. Because it is considered risky to continue relying only on IVM to combat this phenomenon, we assessed the effect of targeting the Onchocerca volvulus Wolbachia endosymbionts with doxycycline for these individuals with suboptimal response. Methods. One hundred sixty-seven patients, most of them with multiple rounds of IVM, were recruited in areas with IVM suboptimal response and treated with 100 mg/day doxycycline for 6 weeks. Three and 12 months after doxycycline treatment, patients took part in standard IVM treatment. Results. At 20 months after treatment, 80% of living female worms from the placebo group were Wolbachia positive, whereas only 5.1% in the doxycycline-treated group contained bacteria. Consistent with interruption of embryogenesis, none of the nodules removed from doxycycline-treated patients contained microfilariae, and 97% of those patients were without microfilaridermia, in contrast to placebo patients who remained at pretreatment levels (P < .001). Moreover, a significantly enhanced number of dead worms were observed after doxycycline. Conclusions. Targeting the Wolbachia in O. volvulus is effective in clearing microfilariae in the skin of onchocerciasis patients with persistent microfilaridermia and in enhanced killing of adult worms after repeated standard IVM treatment. Strategies can now be developed that include doxycycline to control onchocerciasis in areas where infections persist despite the frequent use of IVM. Clinical Trials Registration. ISRCTN 66649839.
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Affiliation(s)
- Alexander Yaw Debrah
- Faculty of Allied Health Sciences, Kwame Nkrumah University of Science and Technology Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana
| | - Sabine Specht
- Institutes for Medical Microbiology, Immunology and Parasitology
| | - Ute Klarmann-Schulz
- Institutes for Medical Microbiology, Immunology and Parasitology Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | - Linda Batsa
- Kumasi Centre for Collaborative Research in Tropical Medicine, Ghana
| | - Sabine Mand
- Institutes for Medical Microbiology, Immunology and Parasitology
| | | | - Rolf Fimmers
- Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | - Bettina Dubben
- Institutes for Medical Microbiology, Immunology and Parasitology
| | | | | | - Daniel Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra
| | - Arcangelo Ricchiuto
- Institutes for Medical Microbiology, Immunology and Parasitology Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany
| | | | - Ohene Adjei
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Charles D Mackenzie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, United Kingdom
| | - Achim Hoerauf
- Institutes for Medical Microbiology, Immunology and Parasitology
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Dunn C, Callahan K, Katabarwa M, Richards F, Hopkins D, Withers PC, Buyon LE, McFarland D. The Contributions of Onchocerciasis Control and Elimination Programs toward the Achievement of the Millennium Development Goals. PLoS Negl Trop Dis 2015; 9:e0003703. [PMID: 25996946 PMCID: PMC4440802 DOI: 10.1371/journal.pntd.0003703] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In 2000, 189 member states of the United Nations (UN) developed a plan for peace and development, which resulted in eight actionable goals known as the Millennium Development Goals (MDGs). Since their inception, the MDGs have been considered the international standard for measuring development progress and have provided a blueprint for global health policy and programming. However, emphasis upon the achievement of priority benchmarks around the "big three" diseases--namely HIV, tuberculosis (TB), and malaria--has influenced global health entities to disproportionately allocate resources. Meanwhile, several tropical diseases that almost exclusively impact the poorest of the poor continue to be neglected, despite the existence of cost-effective and feasible methods of control or elimination. One such Neglected Tropical Disease (NTD), onchocerciasis, more commonly known as river blindness, is a debilitating and stigmatizing disease primarily affecting individuals living in remote and impoverished areas. Onchocerciasis control is considered to be one of the most successful and cost-effective public health campaigns ever launched. In addition to improving the health and well-being of millions of individuals, these programs also lead to improvements in education, agricultural production, and economic development in affected communities. Perhaps most pertinent to the global health community, though, is the demonstrated effectiveness of facilitating community engagement by allowing communities considerable ownership with regard to drug delivery. This paper reviews the contributions that such concentrated efforts to control and eliminate onchocerciasis make to achieving select MDGs. The authors hope to draw the attention of public policymakers and global health funders to the importance of the struggle against onchocerciasis as a model for community-directed interventions to advance health and development, and to advocate for NTDs inclusion in the post 2015 agenda.
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Affiliation(s)
- Caitlin Dunn
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
| | - Kelly Callahan
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Moses Katabarwa
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Frank Richards
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Donald Hopkins
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - P. Craig Withers
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
| | - Lucas E. Buyon
- Health Programs, The Carter Center, Atlanta, Georgia, United States of America
- College of Arts and Sciences, Emory University, Atlanta, Georgia, United States of America
| | - Deborah McFarland
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
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Westblade LF, Fischer PU, Haghi N, Schniederjan MJ, Pritt BS, Long JG, Jerris RC, Garola RE. A five-year-old child with a subcutaneous forehead nodule. Pediatr Dev Pathol 2015; 18:164-6. [PMID: 25569144 DOI: 10.2350/14-08-1545-cr.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We describe a case of a 5-year-old girl with onchocerciasis. The patient was recently adopted from Ethiopia and presented with a firm, raised nodule on the midportion of the forehead. Initially, Langerhans cell histiocytosis with bone involvement was suspected; however, histopathologic analysis of the excised nodule revealed the presence of a young-adult, female Onchocerca volvulus worm. This case exemplifies the importance of recognizing the key morphologic characteristics of adult O. volvulus worms isolated from pediatric patients in nonendemic areas to ensure adroit clinical management.
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Affiliation(s)
- Lars F Westblade
- 1 Department of Pathology, Children's Healthcare of Atlanta, Atlanta, GA, USA
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Endale A, Erko B, Weldegebreal F, Legesse M. Predictors of compliance with community-directed treatment with ivermectin for onchocerciasis control in Kabo area, southwestern Ethiopia. Parasit Vectors 2015; 8:99. [PMID: 25890151 PMCID: PMC4335633 DOI: 10.1186/s13071-015-0695-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 01/26/2015] [Indexed: 11/29/2022] Open
Abstract
Background Compliance with annual ivermectin treatment is a major challenge in community-directed treatment with ivermectin (CDTI) implementation. There are individuals who do not comply with the annual mass treatment, which contributes to the continuity for disease transmission. Hence, ensuring high treatment coverage and sustained compliance should be given due emphasis in the control of onchocerciasis. The aim of this study was to determine CDTI compliance rate and predictors of compliance where the CDTI was in its 9th round in Kabo area, southwestern Ethiopia. Methods Community-based cross-sectional study was conducted in Kabo area, three weeks after the 9th round of annual ivermectin distribution. Systematic random sampling was used to select head of households and structured, pre-tested questionnaire was used to interview the study participants. Data was analyzed using SPSS version 16. Descriptive statistics was used to compute mean and standard deviation of continuous variables and frequency for categorical variables, while bivariate and multivariate logistic regressions were used to assess the effects of independent variables on the outcome variable. Variables which showed association in multivariate analysis were considered as final predictors of compliance and strength of association was measured through adjusted odds ratio (AOR). Results A total of 308 respondents (age range 18-70, mean age ± SD, 32.21 ± 9.64) participated in the study. Of these, 249 (80.8%) reported that they took ivermectin during the 9th round annual treatment. Significantly higher rate of treatment compliance was reported by participants age ≥35 years (AOR = 5.48, 95% CI; 1.97 - 15.23), participants who stayed in the area for more than ten years (AOR = 3.86, 95% CI; 1.83- 8.11), participants who perceive that they are at risk of contracting the disease(AOR = 7.05, 2.70- 18.43), participants who perceive community drug distributors (CDDs) are doing their work well (AOR = 2.35 95% CI; 1.15- 4.83) and participants who know at least one CDD in their village (AOR = 2.83, 95% CI; 1.26- 6.40). Conclusion The majority of the study participants in the present study area complied with ivermectin treatment. Nevertheless, intervention packages should consider factors such as age, residence duration and community’s perception of the disease to improve compliance and make drug distribution sustainable.
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Affiliation(s)
- Adugna Endale
- DireDawa University, School of Medicine, P. O. Box 1362, Dire Dawa, Ethiopia.
| | - Berhanu Erko
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
| | - Fitsum Weldegebreal
- Haramaya University, College of Health and Medical Sciences, Department of Medical Laboratory Science, P. O. Box 235, Harar, Ethiopia.
| | - Mengistu Legesse
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
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Walker M, Specht S, Churcher TS, Hoerauf A, Taylor MJ, Basáñez MG. Therapeutic efficacy and macrofilaricidal activity of doxycycline for the treatment of river blindness. Clin Infect Dis 2014; 60:1199-207. [PMID: 25537873 PMCID: PMC4370165 DOI: 10.1093/cid/ciu1152] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The efficacy of 4–6 weeks of oral doxycycline in depleting Wolbachia from Onchocerca volvulus is >95% in the majority of patients. Wolbachia depletion induces a 70%–80% reduction in worm life span, confirming doxycycline as a potent macrofilaricide. Background. Onchocerca volvulus and lymphatic filariae, causing river blindness and elephantiasis, depend on endosymbiotic Wolbachia bacteria for growth, development, fertility, and survival. Clinical trials have shown that doxycycline treatment eliminates Wolbachia, causing long-term sterilization of adult female filariae and effecting potent macrofilaricidal activity. The continual reinfection by drug-naive worms that occurs in these trial settings dilutes observable anti-Wolbachia and antifilarial effects, making it difficult to estimate therapeutic efficacy and compare different doxycycline regimens, evaluated at different times after treatment. Methods. A meta-analytical modeling framework is developed to link all usable data collected from clinical trials measuring the Wolbachia status and viability of individual female adult worms collected at various times after treatment with 4, 5, or 6 weeks of daily 100 or 200 mg oral doxycycline. The framework is used to estimate efficacy parameters that are not directly measurable as trial outcomes. Results. The estimated efficacy of doxycycline (the maximum proportional reduction in the percentage of adult female O. volvulus positive for Wolbachia) is 91%–94% on average, irrespective of the treatment regimen. Efficacy is >95% in the majority of trial participants. The life span of Wolbachia-depleted worms is reduced by 70%–80%, from approximately 10 years to 2–3 years. Conclusions. The efficacy parameters are pertinent to the prospects of using doxycycline on a “test and treat” basis for onchocerciasis control and confirm doxycycline as a potent macrofilaricidal therapy. The modeling approach is more generally relevant to the design and evaluation of clinical trials for antifilarial drugs conducted in endemic settings.
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Affiliation(s)
- Martin Walker
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - Sabine Specht
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Thomas S Churcher
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
| | - Achim Hoerauf
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Germany
| | - Mark J Taylor
- Department of Parasitology, Liverpool School of Tropical Medicine, United Kingdom
| | - María-Gloria Basáñez
- Department of Infectious Disease Epidemiology, Imperial College London, United Kingdom
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Tamarozzi F, Wright HL, Johnston KL, Edwards SW, Turner JD, Taylor MJ. Human filarial Wolbachia lipopeptide directly activates human neutrophils in vitro. Parasite Immunol 2014; 36:494-502. [PMID: 24909063 PMCID: PMC4282327 DOI: 10.1111/pim.12122] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 06/03/2014] [Indexed: 02/04/2023]
Abstract
The host inflammatory response to the Onchocerca volvulus endosymbiont, Wolbachia, is a major contributing factor in the development of chronic pathology in humans (onchocerciasis/river blindness). Recently, the toll-like pattern recognition receptor motif of the major inflammatory ligands of filarial Wolbachia, membrane-associated diacylated lipoproteins, was functionally defined in murine models of pathology, including mediation of neutrophil recruitment to the cornea. However, the extent to which human neutrophils can be activated in response to this Wolbachia pattern recognition motif is not known. Therefore, the responses of purified peripheral blood human neutrophils to a synthetic N-terminal diacylated lipopeptide (WoLP) of filarial Wolbachia peptidoglycan-associated lipoprotein (PAL) were characterized. WoLP exposure led to a dose-dependent activation of healthy, human neutrophils that included gross morphological alterations and modulation of surface expressed integrins involved in tethering, rolling and extravasation. WoLP exposure induced chemotaxis but not chemokinesis of neutrophils, and secretion of the major neutrophil chemokine, interleukin 8. WoLP also induced and primed the respiratory burst, and enhanced neutrophil survival by delay of apoptosis. These results indicate that the major inflammatory motif of filarial Wolbachia lipoproteins directly activates human neutrophils in vitro and promotes a molecular pathway by which human neutrophils are recruited to sites of Onchocerca parasitism.
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Affiliation(s)
- F Tamarozzi
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
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Baum S, Greenberger S, Pavlotsky F, Solomon M, Enk CD, Schwartz E, Barzilai A. Late-onset onchocercal skin disease among Ethiopian immigrants. Br J Dermatol 2014; 171:1078-83. [PMID: 24673403 DOI: 10.1111/bjd.13005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND Onchocerciasis is an infectious disease caused by the filaria Onchocerca volvulus. Very little is known regarding onchocerciasis imported from endemic to nonendemic areas. OBJECTIVES To evaluate pruritic dermatitis simulating atopic dermatitis in Ethiopian immigrants in Israel. PATIENTS AND METHODS A retrospective study of 27 Ethiopian immigrants to Israel was conducted. Demographics and clinical and laboratory data were collected. RESULTS Of the group of 27 patients, 10 (37%) were men and 17 (63%) were women. The average age at referral was 29 years. All of the patients emigrated from Kuwara, Ethiopia. Diagnosis was done by either positive skin snip test or immunoglobulin (Ig) G4 serology of onchocerciasis in 14 patients. The most common presentation was a combination of lichenified onchodermatitis with atrophy and depigmentation (36%). Eosinophilia and elevated IgE levels were common. Seventeen patients were treated with a single administration of oral ivermectin 200 μg mg(-1). Thirteen patients responded to the treatment. CONCLUSIONS Immigrants from endemic regions to developed countries presenting with pruritic diseases, especially those with a clinical picture suggestive of atopic dermatitis, should be evaluated for possible onchocerciasis infection. Ivermectin, a relatively safe and low-cost treatment, should be considered even in the absence of a proven disease. Physicians should have a high index of suspicion in patients with the corresponding residential history.
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Affiliation(s)
- S Baum
- Department of Dermatology, Chaim Sheba Medical Center, Tel Hashomer, Israel; The Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Turner HC, Walker M, Churcher TS, Basáñez MG. Modelling the impact of ivermectin on River Blindness and its burden of morbidity and mortality in African Savannah: EpiOncho projections. Parasit Vectors 2014; 7:241. [PMID: 24886747 PMCID: PMC4037555 DOI: 10.1186/1756-3305-7-241] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 05/19/2014] [Indexed: 11/17/2022] Open
Abstract
Background The African Programme for Onchocerciasis Control (APOC) has refocused its goals on the elimination of infection where possible, seemingly achievable by 15–17 years of annual mass distribution of ivermectin in some African foci. Previously, APOC had focused on the elimination of onchocerciasis as a public health problem. Timeframes have been set by the World Health Organization, the London Declaration on Neglected Tropical Diseases and the World Bank to achieve these goals by 2020–2025. Methods A novel mathematical model of the dynamics of onchocercal disease is presented which links documented associations between Onchocerca volvulus infection and the prevalence and incidence of morbidity and mortality to model outputs from our host age- and sex-structured onchocerciasis transmission framework (EpiOncho). The model is calibrated for African savannah settings, and used to assess the impact of long-term annual mass administration of ivermectin on infection and ocular and skin disease and to explore how this depends on epidemiological and programmatic variables. Results Current onchocerciasis disease projections, which do not account for excess mortality of sighted individuals with heavy microfilarial loads, underestimate disease burden. Long-term annual ivermectin treatment is highly effective at reducing both the morbidity and mortality associated with onchocerciasis, and this result is not greatly influenced by treatment coverage and compliance. By contrast, impact on microfilarial prevalence and intensity is highly dependent on baseline endemicity, treatment coverage and systematic non-compliance. Conclusions The goals of eliminating morbidity and infection with ivermectin alone are distinctly influenced by epidemiological and programmatic factors. Whilst the former goal is most certainly achievable, reaching the latter will strongly depend on initial endemicity (the higher the endemicity, the greater the magnitude of inter-treatment transmission), advising caution when generalising the applicability of successful elimination outcomes to other areas. The proportion of systematic non-compliers will become far more influential in terms of overall success in achieving elimination goals.
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Affiliation(s)
- Hugo C Turner
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St, Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK.
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Filaria zoogeography in Africa: ecology, competitive exclusion, and public health relevance. Trends Parasitol 2014; 30:163-9. [PMID: 24636357 DOI: 10.1016/j.pt.2014.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 02/04/2014] [Accepted: 02/09/2014] [Indexed: 11/20/2022]
Abstract
Six species of filariae infect humans in sub-Saharan Africa. We hypothesise that these nematodes are able to polyparasitise human hosts by having successfully, through competitive exclusion, adapted to distinct niches. Despite inhabiting the same host, adult stages reside in different tissue sites. Microfilariae of some species exhibit temporal separation by reaching peak levels in the blood at specific times of day. Spatial and temporal distributions in microfilaria location are exploited by the vector feeding-behaviour whereas adult survival is enhanced by occupying exclusive 'ecological' niches of the body. We present specific examples to demonstrate this concept, which is not only important from the biological aspect but important in the context of elimination programmes.
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Crainey JL, Mattos-Glória A, Hamada N, Luz SLB. New tools and insights to assist with the molecular identification of Simulium guianense s.l., main Onchocerca volvulus vector within the highland areas of the Amazonia onchocerciasis focus. Acta Trop 2014; 131:47-55. [PMID: 24200838 DOI: 10.1016/j.actatropica.2013.10.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 11/30/2022]
Abstract
Following the success of the Onchocerciasis Elimination Programme for the Americas (OEPA), there is now just one Latin American onchocerciasis focus where onchocerciasis transmission is described as 'on-going:' the Amazonia Onchocerciasis focus. In the hyperendemic highland areas of the Amazonia focus, Simulium guianense s.l. Wise are the most important vectors of the disease. Populations of S. guianense s.l. are, however, known to vary in their cytogenetics and in a range of behaviours, including in their biting habits. In the hypoendemic lowland areas of the Amazonia focus, for example, S. guianense s.l. are generally regarded as zoophilic and consequently unimportant to disease transmission. Robust tools, to discriminate among various populations of S. guianense s.l. have, however, not yet been developed. In the work reported here, we have assessed the utility of a ribosomal DNA sequence fragment spanning the nuclear ribosomal ITS-1, ITS-2 and 5.8S sequence regions and a ∼850 nucleotide portion of the mitochondrial cytochrome oxidase gene (CO1) for species-level identification and for resolving the within species substructuring. We report here how we have generated 78 CO1 sequences from a rich set of both zoophilic and anthropophilic populations of S. guianense s.l. that were collected from eight sites that are broadly distributed across Brazil. Consistent with previous findings, our analysis supports the genetic isolation of Simulium litobranchium from S. guianense s.l. In contrast with previous findings, however, our results did not provide support for the divergence of the two species prior to the radiation of S. guianense s.l. In our analysis of the S. guianense s.l. ribosomal DNA sequence trace files we generated, we provide clear evidence of multiple within-specimen single nucleotide polymorphisms and indels suggesting that S. guianense s.l. ribosomal DNA is not a good target for conventional DNA barcoding. This is the first report of S. guianense s.l. within individual ribosomal DNA variation and thus the first evidence that the species is not subject to the normal effects of concerted evolution. Collectively, these data illustrate the need for diverse sampling in the development of robust molecular tools for vector identification and suggest that ribosomal DNA might be able to assist with resolving S. guianense s.l. species substructuring that C01 barcoding has hitherto failed to.
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Affiliation(s)
- James L Crainey
- Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane, Fiocruz Amazônia Rua Terezina, 476. Adrianópolis, CEP: 69057-070 Manaus, AM, Brazil
| | - Aline Mattos-Glória
- Lab de Citotaxonomia e Insetos Aquáticos, Instituto Nacional de Pesquisas da Amazônia-INPA, 69011-970 Manaus, AM, Brazil
| | - Neusa Hamada
- Lab de Citotaxonomia e Insetos Aquáticos, Instituto Nacional de Pesquisas da Amazônia-INPA, 69011-970 Manaus, AM, Brazil
| | - Sérgio L B Luz
- Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane, Fiocruz Amazônia Rua Terezina, 476. Adrianópolis, CEP: 69057-070 Manaus, AM, Brazil.
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Abstract
Many hundreds of millions of people throughout the world are infected by nematodes found in the intestine or tissues with a high prevalence in developing countries. Despite their frequency and morbidity, these infections, which may affect migrants and travelers, remain difficult to diagnosis even in developed countries. This is primarily due to the variety of clinical signs often associated with a lack of highly sensitive and specific diagnostic tools. Parasitological diagnosis is often difficult to achieve and can neither be applied during the pre-patent period nor for parasitic impasses. Serological diagnosis is frequently hampered by a lack of specificity due to cross-reaction with others helminthes. Molecular biology methods still require optimization. The diagnostic approach applied by a clinician of a suspected nematode infection is based on a vast set of data including patient history and way of life, clinical examination, non-specific biological tests and, when available, specific diagnostic tests.
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Affiliation(s)
- Coralie L'Ollivier
- Parasitology & Mycology, CHU Timone-Adultes, Aix Marseille Université, Assistance Publique-Hôpitaux de Marseille, 13005 Marseille, France
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Mutafchiev Y, Dantas-Torres F, Giannelli A, Abramo F, Papadopoulos E, Cardoso L, Cortes H, Otranto D. Redescription of Onchocerca lupi (Spirurida: Onchocercidae) with histopathological observations. Parasit Vectors 2013; 6:309. [PMID: 24499611 PMCID: PMC3818983 DOI: 10.1186/1756-3305-6-309] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 10/21/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Onchocerca lupi is a dog parasite of increasing zoonotic concern, with new human cases diagnosed in Turkey, Tunisia, Iran, and the United States. Information about the morphology of this nematode is scant and a detailed re-description of this species is overdue. In addition, histopathological data of potential usefulness for the identification of O. lupi infections are provided. METHODS Male and female nematodes, collected from the connective tissue of a dog, were examined using light microscopy and scanning electron microscopy (SEM), and an histological evaluation was performed on biopsy samples from periocular tissues. RESULTS The morphological identification was confirmed by molecular amplification and partial sequencing of cytochrome oxidase subunit 1 gene. This study provides the first comprehensive morphological and morphometric description of O. lupi from a dog based on light microscopy, SEM, molecular characterization, and histological observations. CONCLUSIONS Data herein presented contribute to a better understanding of this little known parasitic zoonosis, whose impact on human and animal health is still underestimated. The presence of granulomatous reactions only around the female adult suggests that the release of microfilariae from the uterus might be the cause of the inflammatory reaction observed.
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Affiliation(s)
- Yasen Mutafchiev
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Filipe Dantas-Torres
- Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Recife Pernambuco, Brazil
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano, Bari, Italy
| | - Alessio Giannelli
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano, Bari, Italy
| | - Francesca Abramo
- Dipartimento di Patologia Animale, Università di Pisa, Pisa, Italy
| | - Elias Papadopoulos
- Department of Infectious and Parasitic Diseases and Pathology, Faculty of School of Veterinary Medicine, Aristotle, University of Thessaloniki, Thessaloniki, Greece
| | - Luís Cardoso
- Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal
- Parasite Disease Group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Oporto, Portugal
| | - Helder Cortes
- Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Universidade de Évora, Évora, Portugal
| | - Domenico Otranto
- Dipartimento di Medicina Veterinaria, Università degli Studi di Bari, Valenzano, Bari, Italy
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The cost of annual versus biannual community-directed treatment of onchocerciasis with ivermectin: Ghana as a case study. PLoS Negl Trop Dis 2013; 7:e2452. [PMID: 24069497 PMCID: PMC3777881 DOI: 10.1371/journal.pntd.0002452] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/13/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It has been proposed that switching from annual to biannual (twice yearly) mass community-directed treatment with ivermectin (CDTI) might improve the chances of onchocerciasis elimination in some African foci. However, historically, relatively few communities have received biannual treatments in Africa, and there are no cost data associated with increasing ivermectin treatment frequency at a large scale. Collecting cost data is essential for conducting economic evaluations of control programmes. Some countries, such as Ghana, have adopted a biannual treatment strategy in selected districts. We undertook a study to estimate the costs associated with annual and biannual CDTI in Ghana. METHODOLOGY The study was conducted in the Brong-Ahafo and Northern regions of Ghana. Data collection was organized at the national, regional, district, sub-district and community levels, and involved interviewing key personnel and scrutinizing national records. Data were collected in four districts; one in which treatment is delivered annually, two in which it is delivered biannually, and one where treatment takes place biannually in some communities and annually in others. Both financial and economic costs were collected from the health care provider's perspective. PRINCIPAL FINDINGS The estimated cost of treating annually was US Dollars (USD) 0.45 per person including the value of time donated by the community drug distributors (which was estimated at USD 0.05 per person per treatment round). The cost of CDTI was approximately 50-60% higher in those districts where treatment was biannual than in those where it was annual. Large-scale mass biannual treatment was reported as being well received and considered sustainable. CONCLUSIONS/SIGNIFICANCE This study provides rigorous evidence of the different costs associated with annual and biannual CDTI in Ghana which can be used to inform an economic evaluation of the debate on the optimal treatment frequency required to control (or eliminate) onchocerciasis in Africa.
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Conceição PA, Crainey JL, Almeida TP, Shelley AJ, Luz SLB. New molecular identifiers for Simulium limbatum and Simulium incrustatum s.l. and the detection of genetic substructure with potential implications for onchocerciasis epidemiology in the Amazonia focus of Brazil. Acta Trop 2013; 127:118-25. [PMID: 23545131 DOI: 10.1016/j.actatropica.2013.03.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/13/2013] [Accepted: 03/22/2013] [Indexed: 11/28/2022]
Abstract
The Amazonia onchocerciasis focus of southern Venezuela and northern Brazil is the larger of the two remaining Latin American onchocerciasis foci where disease transmission still occurs and is often regarded as the most challenging of all the Latin American foci to eliminate onchocerciasis. The site is home to a population of over 20,000 semi-nomadic, hunter-gatherer Yanomami people and is made-up of a mosaic of rainforest and savannah ecologies, which are influenced by the area's undulating terrain and rich geological diversity. At least six blackfly vectors have been implicated in onchocerciasis transmission in this focus; however, because of the difficulty in their routine identification the relative importance of each has been obscured. Simulium limbatum and Simulium incrustatum s.l. have both been recorded as vectors in the Amazonia focus, but they are difficult to discriminate morphologically and thus the ecological range of these species, and indeed the presence of S. limbatum in the Amazonia focus at all, have remained controversial. In the work described here, we report 15 S. incrustatum s.l. CO1 sequences and 27 S. limbatum sequences obtained from field-caught adult female blackflies collected from forest and savannah localities, inside and just outside the Amazonia focus. Phylogenetic analysis with the sequences generated in this study, showed that both the S. limbatum and the S. incrustatum s.l. CO1 sequences obtained (even from specimens living in sympatry) all fell into discrete species-specific bootstrap-supported monophyletic groups and thus confirmed the utility of the CO1 gene for identifying both these species inside the Amazonia focus. As the S. limbatum-exclusive cluster included CO1 sequences obtained from forest-caught and morphologically identified specimens these results provide the clearest evidence yet of the presence of S. limbatum inside the Amazonia focus. The question, however, of whether S. limbatum is actually a vector in the focus still remains unanswered as the data presented here also suggest that S. limbatum found in the savannahs adjacent to, but outside the Amazonia focus (and which represent the only S. limbatum population to be unambiguously incriminated as a host of Onchocerca volvulus), are genetically distinct from those living inside the focus. These findings highlight the need for a clearer picture of the vector taxonomy inside the Amazonia onchocerciasis focus.
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Affiliation(s)
- Priscila A Conceição
- Ecologia de Doenças Transmissíveis na Amazônia, Instituto Leônidas e Maria Deane - Fiocruz Amazônia Rua Terezina, 476. Adrianópolis, CEP: 69.057-070 Manaus, Amazonas, Brazil
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Golden A, Steel C, Yokobe L, Jackson E, Barney R, Kubofcik J, Peck R, Unnasch TR, Nutman TB, de los Santos T, Domingo GJ. Extended result reading window in lateral flow tests detecting exposure to Onchocerca volvulus: a new technology to improve epidemiological surveillance tools. PLoS One 2013; 8:e69231. [PMID: 23935960 PMCID: PMC3720650 DOI: 10.1371/journal.pone.0069231] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 06/06/2013] [Indexed: 11/19/2022] Open
Abstract
Onchocerciasis is a neglected tropical disease caused by infection with the parasite Onchocerca volvulus (Ov). An estimated 180 million people are at risk for Ov infection, and 37 million people are infected, mostly in Africa. A lateral flow-based assay to detect human IgG4 antibodies to the Ov-specific antigen Ov-16 was developed as a rapid tool to detect exposure to Ov. The test, when performed on 449 sera specimens from patients with microfiladermia and Ov-negative patients, has a sensitivity of 89.1% (95% confidence interval: 86.2%-92.0%), and specificity of 97% (95% confidence interval: 95.4%-98.6%). Because the intended use of the test is for surveillance, it is highly desirable to have a stable, long-lasting result. An extended read window is thus desirable for a high-volume, busy workflow and facilitates post-surveillance quality assurance. The main restriction on achieving an extended read window for this assay was the erythrocyte lysis that can alter the signal-to-noise ratio, especially in those with low IgG4 levels (weak positives). We describe a test housing that incorporates a user-independent feature driven by assay fluid and an expanding wick that detaches the blood separation membrane from the nitrocellulose used in the assay, but before hemolysis occurs. We demonstrated material functionality at extreme operational conditions (37°C, 80% relative humidity) and a read window of a minimum of 70 days. The fluid-driven assay device performs equally as well with whole blood as with plasma, as demonstrated with 100 spiked clinical specimens (with a correlation coefficient of 0.96). We show a novel, inexpensive, and simple approach to actuating the detachment of the blood separation membrane from the nitrocellulose test with no impact on the performance characteristics of the test.
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Affiliation(s)
- Allison Golden
- Diagnostics Group, PATH, Seattle, Washington, United States of America
| | - Cathy Steel
- The Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Lindsay Yokobe
- Diagnostics Group, PATH, Seattle, Washington, United States of America
| | - Emily Jackson
- Diagnostics Group, PATH, Seattle, Washington, United States of America
| | - Rebecca Barney
- Diagnostics Group, PATH, Seattle, Washington, United States of America
| | - Joseph Kubofcik
- The Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Roger Peck
- Diagnostics Group, PATH, Seattle, Washington, United States of America
| | - Thomas R. Unnasch
- Department of Global Health, Global Health Infectious Disease Research Program, University of South Florida, Tampa, Florida, United States of America
| | - Thomas B. Nutman
- The Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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Morris CP, Evans H, Larsen SE, Mitre E. A comprehensive, model-based review of vaccine and repeat infection trials for filariasis. Clin Microbiol Rev 2013; 26:381-421. [PMID: 23824365 PMCID: PMC3719488 DOI: 10.1128/cmr.00002-13] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY Filarial worms cause highly morbid diseases such as elephantiasis and river blindness. Since the 1940s, researchers have conducted vaccine trials in 27 different animal models of filariasis. Although no vaccine trial in a permissive model of filariasis has provided sterilizing immunity, great strides have been made toward developing vaccines that could block transmission, decrease pathological sequelae, or decrease susceptibility to infection. In this review, we have organized, to the best of our ability, all published filaria vaccine trials and reviewed them in the context of the animal models used. Additionally, we provide information on the life cycle, disease phenotype, concomitant immunity, and natural immunity during primary and secondary infections for 24 different filaria models.
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Affiliation(s)
- C. Paul Morris
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Holly Evans
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Sasha E. Larsen
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Edward Mitre
- Department of Microbiology and Immunology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
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Kurosinski MA, Lüersen K, Ndjonka D, Younis AE, Brattig NW, Liebau E. Filarial parasites possess an antizyme but lack a functional ornithine decarboxylase. Acta Trop 2013; 126:167-76. [PMID: 23474393 DOI: 10.1016/j.actatropica.2013.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 10/27/2022]
Abstract
In eukaryotes, the key player in polyamine metabolism is the ornithine decarboxylase (ODC) that catalyses the first and rate limiting step in cellular polyamine synthesis. The half life of ODC is strictly regulated by the antizyme (AZ), which promotes its degradation. Older reports on the polyamine situation in filarial parasites indicate a lack of ornithine decarboxylation activity and an increased uptake of polyamines. Our in silico analysis of the Brugia malayi genome revealed only an ODC-like protein that lacks essential residues. Consequently, the recombinant protein had no enzymatic ODC activity. Furthermore, only ODC-like genes were found in the available draft genomes of other filarial parasites. In this ODC-free scenario, we set out to investigate the AZ of O. volvulus (OvAZ). The expression of the recombinant protein allowed us to analyse the localization of OvAZ in different O. volvulus stages as well as to identify it as target for the human humoral immune response. Strong immunostaining was observed in the outer zone of the uterine epithelium as well as in the uterus lumen around the periphery of the developing parasite, indicating a potential role of the OvAZ in the control of polyamine levels during embryonic development. By employing a novel in vivo method using Caenorhabditis elegans, we postulate that the OvAZ enters the secretory pathway. Even though the ODCs are absent in filarial parasites, OvAZ has the ability to bind to various ODCs, thereby demonstrating the functionality of the conserved AZ-binding domains. Finally, pull-down assays show an interaction between B. malayi AZ and the B. malayi ODC-like protein, indicating that the B. malayi ODC-like protein might function as an AZI. Taken together, our results suggest that filarial species do not possess the ODC while retaining the ODC-regulatory proteins AZ and AZI. It is tempting to speculate that both proteins are retained for the regulation of polyamine transport systems.
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Ratmanov P, Mediannikov O, Raoult D. Vectorborne diseases in West Africa: geographic distribution and geospatial characteristics. Trans R Soc Trop Med Hyg 2013; 107:273-84. [PMID: 23479360 DOI: 10.1093/trstmh/trt020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
This paper provides an overview of the methods in which geographic information systems (GIS) and remote sensing (RS) technology have been used to visualise and analyse data related to vectorborne diseases (VBD) in West Africa and to discuss the potential for these approaches to be routinely included in future studies of VBDs. GIS/RS studies of diseases that are associated with a specific geographic landscape were reviewed, including malaria, human African trypanosomiasis, leishmaniasis, lymphatic filariasis, Loa loa filariasis, onchocerciasis, Rift Valley fever, dengue, yellow fever, borreliosis, rickettsioses, Buruli ulcer and Q fever. RS data and powerful spatial modelling methods improve our understanding of how environmental factors affect the vectors and transmission of VBDs. There is great potential for the use of GIS/RS technologies in the surveillance, prevention and control of vectorborne and other infectious diseases in West Africa.
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Affiliation(s)
- Pavel Ratmanov
- Aix Marseille Université, URMITE, UMR CNRS 7278, IRD 198, INSERM 1095, 27 Boulevard Jean Moulin, 13385 Marseille cedex 05, France
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Waterborne Infectious Diseases, Approaches to Control. Infect Dis (Lond) 2013. [DOI: 10.1007/978-1-4614-5719-0_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Jaggernath J, Haslam D, Naidoo KS. Climate change: Impact of increased ultraviolet radiation and water changes on eye health. Health (London) 2013. [DOI: 10.4236/health.2013.55122] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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CrypticOnchocercaspecies infecting North American cervids, with implications for the evolutionary history of host associations inOnchocerca. Parasitology 2012; 140:1201-10. [DOI: 10.1017/s0031182012001758] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYParasites in the genusOnchocercainfect humans, ruminants, camels, horses, suids, and canids, with effects ranging from relatively benign to debilitating. In North America,Onchocerca cervipedisis the sole species known to infect cervids, while at least 5Onchocercaspecies infect Eurasian cervids. In this study, we report the discovery of a cervid-parasitizingOnchocercaonly distantly related toO. cervipedis. To reconstruct the phylogenetic history of the genusOnchocerca, we used newly acquired DNA sequence fromO. cervipedis(from moose in Northwest Territories, Canada) and from the newly discovered species (from white-tailed deer in upstate New York), as well as previously published sequences. Ancestral host reconstructions suggest that host switches have been common throughout the evolutionary history ofOnchocerca, and that bovid- and cervid-parasitizing species have been particularly important sources of descendant species. North America cervids might therefore serve as a source forOnchocercainvasions into new hosts. Given the high density of deer populations, the potential for zoonotic infections may also exist. Our discovery of a newOnchocercaspecies with relatively limited sampling suggests that the diversity ofOnchocercaassociated with cervids in North America may be greater than previously thought, and surveys utilizing molecules and morphology are necessary.
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Predictive and epidemiologic modeling of the spatial risk of human onchocerciasis using biophysical factors: a case study of Ghana and Burundi. Spat Spatiotemporal Epidemiol 2012; 3:273-85. [PMID: 23149324 DOI: 10.1016/j.sste.2012.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 08/09/2012] [Accepted: 08/10/2012] [Indexed: 11/21/2022]
Abstract
Although recent efforts taken have substantially contained human onchocerciasis in many African countries, published reports indicate a recrudescence of the disease. To understand this problem, biophysical factors that favor the establishment of human onchocerciasis in Ghana and Burundi-countries identified as threat locations of recrudescence for neighboring countries-were analyzed. Data pertaining to the prevalence of human onchocerciasis in both countries was obtained from published sources. Findings in this study suggest that there was a gradient in prevalence of onchocerciasis in geographic locations near the water streams. The predictive models suggest that rainfall, humidity, and elevation were statistically significant for Burundi data while in Ghana, only the effect of elevation was highly significant (p<0.0001). In 2010, the estimated at-risk population was 4,817,280 people (19.75% of the total population) and 522,773 people (6.23% of the total population) in Ghana and Burundi, respectively. Findings can help in the effective design of preventive control measures.
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Knopp S, Steinmann P, Hatz C, Keiser J, Utzinger J. Nematode Infections:. Infect Dis Clin North Am 2012; 26:359-81. [DOI: 10.1016/j.idc.2012.02.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Otranto D, Dantas-Torres F, Cebeci Z, Yeniad B, Buyukbabani N, Boral OB, Gustinelli A, Mounir T, Mutafchiev Y, Bain O. Human ocular filariasis: further evidence on the zoonotic role of Onchocerca lupi. Parasit Vectors 2012; 5:84. [PMID: 22541132 PMCID: PMC3407723 DOI: 10.1186/1756-3305-5-84] [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] [Received: 04/08/2012] [Accepted: 04/27/2012] [Indexed: 11/13/2022] Open
Abstract
Background Among ocular vector-borne pathogens, Onchocerca volvulus, the agent of the so-called “river blindness”, affects about 37 million people globally. Other Onchocerca spp. have been sporadically reported as zoonotic agents. Cases of canine onchocerciasis caused by Onchocerca lupi are on the rise in the United States and Europe. Its zoonotic role has been suspected but only recently ascertained in a single case from Turkey. The present study provides further evidence on the occurrence of O. lupi infesting human eyes in two patients from Turkey (case 1) and Tunisia (case 2). The importance of obtaining a correct sample collection and preparation of nematodes infesting human eyes is highlighted. Methods In both cases the parasites were identified with morpho-anatomical characters at the gross examination, histological analysis and anatomical description and also molecularly in case 1. Results The nematode from the first case was obviously O. lupi based on their morphology at the gross examination, histological analysis and anatomical description. In the second case, although the diagnostic cuticular characters were not completely developed, other features were congruent with the identification of O. lupi. Furthermore, the morphological identification was also molecularly confirmed in the Turkish case. Conclusions The results of this study suggest that O. lupi infestation is not an occasional finding but it should be considered in the differential diagnosis of other zoonotic helminths causing eye infestation in humans (e.g., D. immitis and Dirofilaria repens). Both cases came from areas where no cases of canine onchocerciasis were previously reported in the literature, suggesting that an in depth appraisal of the infestation in canine populations is necessary. Physicians and ophthalmologists are advised on how to preserve nematode samples recovered surgically, to allow a definitive, correct etiological diagnosis.
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Affiliation(s)
- Domenico Otranto
- Dipartimento di Sanità Pubblica Veterinaria e Zootecnia, Università degli Studi di Bari, Bari, Valenzano, Italy.
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Abstract
A disproportionate burden of helminthiases in human populations occurs in marginalised, low-income, and resource-constrained regions of the world, with over 1 billion people in developing areas of sub-Saharan Africa, Asia, and the Americas infected with one or more helminth species. The morbidity caused by such infections imposes a substantial burden of disease, contributing to a vicious circle of infection, poverty, decreased productivity, and inadequate socioeconomic development. Furthermore, helminth infection accentuates the morbidity of malaria and HIV/AIDS, and impairs vaccine efficacy. Polyparasitism is the norm in these populations, and infections tend to be persistent. Hence, there is a great need to reduce morbidity caused by helminth infections. However, major deficiencies exist in diagnostics and interventions, including vector control, drugs, and vaccines. Overcoming these deficiencies is hampered by major gaps in knowledge of helminth biology and transmission dynamics, platforms from which to help develop such tools. The Disease Reference Group on Helminths Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. In this review, we provide an overview of the forces driving the persistence of helminthiases as a public health problem despite the many control initiatives that have been put in place; identify the main obstacles that impede progress towards their control and elimination; and discuss recent advances, opportunities, and challenges for the understanding of the biology, epidemiology, and control of these infections. The helminth infections that will be discussed include: onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, food-borne trematodiases, and taeniasis/cysticercosis.
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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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Tamarozzi F, Tendongfor N, Enyong PA, Esum M, Faragher B, Wanji S, Taylor MJ. Long term impact of large scale community-directed delivery of doxycycline for the treatment of onchocerciasis. Parasit Vectors 2012; 5:53. [PMID: 22433114 PMCID: PMC3350421 DOI: 10.1186/1756-3305-5-53] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 03/20/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anti-Wolbachia treatment with doxycycline is effective in sterilising and killing adult Onchocerca volvulus nematodes, proving superior to ivermectin and of great potential as an alternative approach for the treatment and control of onchocerciasis, particularly in areas of Loa loa co-endemicity. Nevertheless, the length of the required treatment poses potential logistical problems and risk of poor compliance, raising a barrier to the use of doxycycline in Mass Drug Administration (MDA) strategies. In 2007 and 2008 a feasibility trial of community-directed treatment with doxycycline was carried out in two health districts in Cameroon, co-endemic for O. volvulus and L. loa. With 17,519 eligible subjects, the therapeutic coverage was 73.8% with 97.5% compliance, encouraging the feasibility of using doxycycline community-directed delivery in restricted populations of this size. The current study evaluated the effectiveness of this community-directed delivery of doxycycline four years after delivery. FINDINGS Infection with O. volvulus was evaluated by skin biopsy and nodule palpation. Of the 507 subjects recruited, 375 had completed the treatment with doxycycline followed by one or two rounds of annual ivermectin MDA and 132 received one or two rounds of annual ivermectin MDA alone. Statistically significant lower microfilarial prevalence (17.0% [doxycycline plus ivermectin group], 27.0% [ivermectin only group], p = 0.014) and load (p = 0.012) were found in people that had received doxycycline followed by ivermectin compared to those who received ivermectin only. CONCLUSIONS This study demonstrates the long-term effectiveness of doxycycline treatment delivered with a community-directed strategy even when evaluated four years after delivery in an area of ongoing transmission. This finding shows that a multi-week course of treatment is not a barrier to community-delivery of MDA in restricted populations of this size and supports its implementation to compliment existing control strategies for onchocerciasis, where needed.
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Affiliation(s)
- Francesca Tamarozzi
- Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
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Rodríguez-Pérez MA, Unnasch TR, Real-Najarro O. Assessment and monitoring of onchocerciasis in Latin America. ADVANCES IN PARASITOLOGY 2012; 77:175-226. [PMID: 22137585 DOI: 10.1016/b978-0-12-391429-3.00008-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Onchocerciasis has historically been one of the leading causes of infectious blindness worldwide. It is endemic to tropical regions both in Africa and Latin America and in the Yemen. In Latin America, it is found in 13 foci located in 6 different countries. The epidemiologically most important focus of onchocerciasis in the Americas is located in a region spanning the border between Guatemala and Mexico. However, the Amazonian focus straddling the border of Venezuela and Brazil is larger in overall area because the Yanomami populations are scattered over a very large geographical region. Onchocerciasis is caused by infection with the filarial parasite Onchocerca volvulus. The infection is spread through the bites of an insect vector, black flies of the genus Simulium. In Africa, the major vectors are members of the S. damnosum complex, while numerous species serve as vectors of the parasite in Latin America. Latin America has had a long history of attempts to control onchocerciasis, stretching back almost 100 years. The earliest programmes used a strategy of surgical removal of the adult parasites from affected individuals. However, because many of the adult parasites lodge in undetectable and inaccessible areas of the body, the overall effect of this strategy on the prevalence of infection was relatively minor. In 1988, a new drug, ivermectin, was introduced that effectively killed the larval stage (microfilaria) of the parasite in infected humans. As the microfilaria is both the stage that is transmitted by the vector fly and the cause of most of the pathologies associated with the infection, ivermectin opened up a new strategy for the control of onchocerciasis. Concurrent with the use of ivermectin for the treatment of onchocerciasis, a number of sensitive new diagnostic tools were developed (both serological and nucleic acid based) that provided the efficiency, sensitivity and specificity necessary to monitor the decline and eventual elimination of onchocerciasis as a result of successful control. As a result of these advances, a strategy for the elimination of onchocerciasis was developed, based upon mass distribution of ivermectin to afflicted communities for periods lasting long enough to ensure that the parasite population was placed on the road to local elimination. This strategy has been applied for the past decade to the foci in Latin America by a programme overseen by the Onchocerciasis Elimination Program for the Americas (OEPA). The efforts spearheaded by OEPA have been very successful, eliminating ocular disease caused by O. volvulus, and eliminating and interrupting transmission of the parasite in 8 of the 13 foci in the region. As onchocerciasis approaches elimination in Latin America, several questions still need to be addressed. These include defining an acceptable upper limit for transmission in areas in which transmission is thought to have been suppressed (e.g. what is the maximum value for the upper bound of the 95% confidence interval for transmission rates in areas where transmission is no longer detectable), how to develop strategies for conducting surveillance for recrudescence of infection in areas in which transmission is thought to be interrupted and how to address the problem in areas where the mass distribution of ivermectin seems to be unable to completely eliminate the infection.
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Affiliation(s)
- Mario A Rodríguez-Pérez
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Ciudad Reynosa, Tamaulipas, México
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Osei-Atweneboana MY, Boakye DA, Awadzi K, Gyapong JO, Prichard RK. Genotypic analysis of β-tubulin in Onchocerca volvulus from communities and individuals showing poor parasitological response to ivermectin treatment. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 2:20-8. [PMID: 24533268 DOI: 10.1016/j.ijpddr.2012.01.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/23/2012] [Accepted: 01/24/2012] [Indexed: 11/16/2022]
Abstract
Ivermectin (IVM) has been in operational use for the control of onchocerciasis for two decades and remains the only drug of choice. To investigate the parasitological responses and genetic profile of Onchocerca volvulus, we carried out a 21 month epidemiological study to determine the response of the parasite to IVM in 10 Ghanaian endemic communities. Onchocerca nodules were surgically removed from patients in three IVM response categories (good, intermediate and poor) and one IVM naïve community. DNA from adult worms was analyzed to determine any association between genotype and IVM response phenotypic. Embryogramme analysis showed significantly higher reproductive activity in worms from poor response communities, which had up to 41% of females with live stretched microfilaria (mf) in utero, despite IVM treatment, compared with good response communities, which had no intra-uterine stretched mf. β-tubulin isotype 1 gene has been shown to be linked to IVM selection in O. volvulus and also known to be associated with IVM resistance in veterinary nematodes. We have genotyped the full length genomic DNA sequence of the β-tubulin gene from 127 adult worms obtained from the four community categories. We found SNPs at 24 sites over the entire 3696 bp. Eight of the SNPs occurred at significantly higher (p < 0.05) frequencies in the poor response communities compared with the good response communities and the IVM naïve community. Phenotypic and genotypic analyses show that IVM resistance has been selected and the genotype (1183GG/1188CC/1308TT/1545GG) was strongly associated with the resistance phenotype. Since the region in the β-tubulin gene where these four SNPs occur is within 362 bp, it is feasible to develop a genetic marker for the early detection of IVM resistance.
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Affiliation(s)
- Mike Y Osei-Atweneboana
- Institute of Parasitology, McGill University, Canada ; Council for Scientific and Industrial Research-Water Research Institute, Ghana
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, University of Ghana, Ghana
| | - Kwablah Awadzi
- Onchocerciasis Chemotherapy Research Center, Hohoe, Ghana
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Albers A, Esum ME, Tendongfor N, Enyong P, Klarmann U, Wanji S, Hoerauf A, Pfarr K. Retarded Onchocerca volvulus L1 to L3 larval development in the Simulium damnosum vector after anti-wolbachial treatment of the human host. Parasit Vectors 2012; 5:12. [PMID: 22236497 PMCID: PMC3311148 DOI: 10.1186/1756-3305-5-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 01/11/2012] [Indexed: 11/10/2022] Open
Abstract
Background The human parasite Onchocerca volvulus harbours Wolbachia endosymbionts essential for worm embryogenesis, larval development and adult survival. In this study, the development of Wolbachia-depleted microfilariae (first stage larvae) to infective third stage larvae (L3) in the insect vector Simulium damnosum was analysed. Methods Infected volunteers in Cameroon were randomly and blindly allocated into doxycycline (200 mg/day for 6 weeks) or placebo treatment groups. After treatment, blackflies were allowed to take a blood meal on the volunteers, captured and dissected for larval counting and DNA extraction for quantitative real-time PCR analysis. Results PCR results showed a clear reduction in Wolbachia DNA after doxycycline treatment in microfilariae from human skin biopsies with > 50% reduction at one month post-treatment, eventually reaching a reduction of > 80%. Larval stages recovered from the insect vector had similar levels of reduction of endosymbiotic bacteria. Larval recoveries were analysed longitudinally after treatment to follow the kinetics of larval development. Beginning at three months post-treatment, significantly fewer L3 were seen in the blackflies that had fed on doxycycline treated volunteers. Concomitant with this, the proportion of second stage larvae (L2) was significantly increased in this group. Conclusions Doxycycline treatment and the resulting decline of Wolbachia endobacteria from the microfilaria resulted in retarded development of larvae in the insect vector. Thus, anti-wolbachial treatment could have an additive effect for interrupting transmission by reducing the number of L3 that can be transmitted by blackflies.
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Affiliation(s)
- Anna Albers
- Institute for Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Sigmund-Freud-Str, 25, D-53105 Bonn, Germany
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Segura-Cabrera A, Bocanegra-García V, Lizarazo-Ortega C, Guo X, Correa-Basurto J, Rodríguez-Pérez MA. A computational analysis of the binding mode of closantel as inhibitor of the Onchocerca volvulus chitinase: insights on macrofilaricidal drug design. J Comput Aided Mol Des 2011; 25:1107-19. [PMID: 22101363 DOI: 10.1007/s10822-011-9489-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 11/08/2011] [Indexed: 11/30/2022]
Abstract
Onchocerciasis is a leading cause of blindness with at least 37 million people infected and more than 120 million people at risk of contracting the disease; most (99%) of this population, threatened by infection, live in Africa. The drug of choice for mass treatment is the microfilaricidal Mectizan(®) (ivermectin); it does not kill the adult stages of the parasite at the standard dose which is a single annual dose aimed at disease control. However, multiple treatments a year with ivermectin have effects on adult worms. The discovery of new therapeutic targets and drugs directed towards the killing of the adult parasites are thus urgently needed. The chitinase of filarial nematodes is a new drug target due to its essential function in the metabolism and molting of the parasite. Closantel is a potent and specific inhibitor of chitinase of Onchocerca volvulus (OvCHT1) and other filarial chitinases. However, the binding mode and specificity of closantel towards OvCHT1 remain unknown. In the absence of a crystallographic structure of OvCHT1, we developed a homology model of OvCHT1 using the currently available X-ray structures of human chitinases as templates. Energy minimization and molecular dynamics (MD) simulation of the model led to a high quality of 3D structure of OvCHIT1. A flexible docking study using closantel as the ligand on the binding site of OvCHIT1 and human chitinases was performed and demonstrated the differences in the closantel binding mode between OvCHIT1 and human chitinase. Furthermore, molecular dynamics simulations and free-energy calculation were employed to determine and compare the detailed binding mode of closantel with OvCHT1 and the structure of human chitinase. This comparative study allowed identification of structural features and properties responsible for differences in the computationally predicted closantel binding modes. The homology model and the closantel binding mode reported herein might help guide the rational development of novel drugs against the adult parasite of O. volvulus and such findings could be extrapolated to other filarial neglected diseases.
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Affiliation(s)
- Aldo Segura-Cabrera
- Laboratorio de Bioinformática, Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Boulevard del Maestro esquina Elías Piña, Colonia Narciso Mendoza, 88710, Ciudad Reynosa, Tamaulipas, México.
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Kamga HLF, Shey DN, Assob JCN, Njunda AL, Nde Fon P, Njem PK. Prevalence of onchocerciasis in the Fundong Health District, Cameroon after 6 years of continuous community-directed treatment with ivermectin. Pan Afr Med J 2011; 10:34. [PMID: 22187616 PMCID: PMC3240934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 10/21/2011] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Onchocerciasis is one of the leading infectious causes of blindness affecting over 37 million people of which 99% are in Africa. The purpose of this study was to determine the prevalence of onchocerciasis in the Fundong Health District, a locality where community-directed treatment with ivermectin has been carried out for 6 consecutive years. METHODS Questionnaires covering participants' identity, Rapid Epidemiological Assessment (REA) for onchocerciasis and parasitological parameters were distributed to participants. Skin snip (SS) was collected for laboratory investigation. RESULTS A total of 404 participants belonging to 200 households were randomly selected from the Fundong Health District, of which 134 (33.2%) were males and 270(66.8%) were females, 14 (3.5%) had microfilaredermia and 15(3.7%) had nodules. There was no significant difference in the prevalence of microfilaredermia with respect to age of participants (X(2)=2.749, P=0.601). There was however a statistically significant difference in the prevalence of nodule and impaired vision/eye itching (IVIE) with respect to age (X(2)=24.67, P<0.001). The greatest rate of infection was found among farmers (2.5%) followed by students (0.7%) and businessmen (0.25%). CONCLUSION This study shows that the study area is now hypo-endemic for onchocerciasis, following 6 years of continuous treatment with ivermectin. Careful monitoring of onchocerciasis should however be continued to avoid that the area returns to its initial hyper endemicity.
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Affiliation(s)
- Henri Lucien Fouamno Kamga
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Cameroon,Corresponding author: Henri Lucien Kamga, Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Cameroon
| | - Dickson Nsagha Shey
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Cameroon
| | | | - Anna Longdoh Njunda
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Cameroon
| | - Peter Nde Fon
- Department of Public Health and Hygiene, Faculty of Health Sciences, University of Buea, Cameroon
| | - Peter Kindong Njem
- Department of Medical Laboratory Sciences, Faculty of Health Sciences, University of Buea, Cameroon
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Onchocerciasis: the role of Wolbachia bacterial endosymbionts in parasite biology, disease pathogenesis, and treatment. Clin Microbiol Rev 2011; 24:459-68. [PMID: 21734243 DOI: 10.1128/cmr.00057-10] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The discovery of Wolbachia intracellular bacteria within filarial nematodes, including Onchocerca volvulus, the causative agent of onchocerciasis or "river blindness," has delivered a paradigm shift in our understanding of the parasite's biology, to where we now know that the bacterial endosymbionts are essential for normal development of larvae and embryos and may support the long-term survival of adult worms. The apparent mutualistic dependency has also offered a novel approach to the treatment of onchocerciasis through the use of antibiotics to eliminate Wolbachia, delivering for the first time a treatment which has significant macrofilaricidal efficacy. Studies with other filarial nematode species have also highlighted a role for Wolbachia in transmission and infection of the mammalian host through a fascinating manipulation of mast cell-mediated vasodilation to enhance infectivity of vector-borne larvae. Wolbachia has also been identified as the principal driver of innate and adaptive Th1 inflammatory immunity, which can either contribute to disease pathogenesis or, with the Wolbachia-mediated recruitment of mast cells, enhance infectivity. The Wolbachia activation of innate inflammation also drives inflammatory adverse events in response to chemotherapy with either diethylcarbamazine (DEC) or ivermectin. In this review we summarize the experimental and field trial data which have uncovered the importance of Wolbachia symbiosis in onchocerciasis.
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Kareiva P. Filling the Breach: Stepping up to the Challenge of Underfunded Sustainability Science. Bioscience 2011. [DOI: 10.1525/bio.2011.61.11.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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98
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Post RJ, Onyenwe E, Somiari SAE, Mafuyai HB, Crainey JL, Ubachukwu PO. A guide to the Simulium damnosum complex (Diptera: Simuliidae) in Nigeria, with a cytotaxonomic key for the identification of the sibling species. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2011; 105:277-97. [PMID: 21871165 DOI: 10.1179/136485911x12987676649700] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Although approximately 40% of all the people blinded by Onchocerca volvulus are Nigerians, almost nothing was known about the various cytospecies of the blackfly vectors present in Nigeria until 1981. The activation of the Nigerian National Onchocerciasis Control Programme in 1986 (and that programme's initiation of mass distributions of ivermectin in 1991) provided a significant stimulus to understand the biology of the Nigerian vectors but the exploration of any possible differences between the cytospecies has been hampered by a lack of accessible taxonomic information. This review attempts to satisfy that need. There are nine different cytoforms reliably recorded from Nigeria (Simulium damnosum s.s. Nile form, S. damnosum s.s. Volta form, S. sirbanum Sirba form, S. sirbanum Sudanense form, S. soubrense Beffa form, S. squamosum A, S. squamosum B, S. squamosum C and S. yahense typical form), and three more are known from surrounding countries and might be reasonably expected to occur in Nigeria. All of these cytospecies are presumed to be vectors, although there have been almost no identifications of the vectors of O. volvulus in Nigeria. The biogeographical distribution of the cytoforms is broadly similar to that known in other parts of West Africa (although many of the cytoforms remain insufficiently studied). The physico-chemical hydrology of the Nigerian breeding sites of the cytospecies does not, however, correspond to that seen elsewhere in West Africa, and it is not clear whether this might be related to differences in the cytoforms. An illustrated cytotaxonomic key is presented to facilitate and encourage future studies.
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Affiliation(s)
- R J Post
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, U.K.
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Dori GU, Belay T, Belete H, Panicker KN, Hailu A. Parasitological and clinico-epidemiological features of onchocerciasis in West Wellega, Ethiopia. J Parasit Dis 2011; 36:10-8. [PMID: 23542576 DOI: 10.1007/s12639-011-0063-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 08/11/2011] [Indexed: 10/17/2022] Open
Abstract
Onchocerciasis is a disease of public health and socio-economic importance in Ethiopia. The aim of this study was to assess parasitological and clinico-epidemiological features of onchocerciasis in the Anfilo District, West Wellega, prior to implementation of Community Directed Treatment with Ivermectin (CDTI) to generate epidemiological and parasitological data for use in control program of the disease and subsequent evaluation of CDTI. A cross-sectional study was conducted in Anfilo District of West Wellega zone during a period of 1 month: from mid-August to mid-September 2006. Data on socio-demographic characteristics were collected using a standardized questionnaire prepared for this purpose. All persons were examined clinically for skin signs and symptoms of onchocerciasis. Two skin snips, one from each side of the gluteal fold were taken using blood lancet and sterilized razor blade and examined for microfilaria. All data were categorized, coded, entered in a data base and analyzed using SPSS version 15.0. for windows. A total of 1114 individuals ≥15 years were examined for microfilariae (mf) of Onchocerca volvulus and onchocercal skin disease (OSD). The prevalence of onchocercal (mf) carrier was 74.8% (833/1114). In both genders, the prevalence of onchocerciasis showed direct correlations with the age of individuals (R (2) = 0.79, P < 0.05). The infection rate varied with the occupation of the study subjects, with preponderance among farmers. Among the subjects with onchocerciasis, the mf density ranged from 1.0 to 711.0 per mg of skin snip with a mean density (SD) and median values of 32.1 (61.5) and 10.4 respectively. The overall community microfilariae load (CMFL), the most sensitive parasitological indicator of onchocerciasis was 19.6. The pervasiveness of OSD among the study subjects was 26.4%. OSD was more frequent in males (32.4%) than their female counterparts (20.8%, P < 0.05). The overall prevalence of onchocercal nodule carrier, the symptom opted for determining the community-wide prevalence of onchocerciasis was 12.1%. Leopard skin, the proxy of longstanding infection of onchocerciasis in the community, was also relatively high (19.1%). The abundance of mf in skin would definitely lead to high transmission potential in the Anfilo District. The situation in the Anfilo District should call for continued CDTI, owing to success of similar recommendations for such programmes in other parts of the country and elsewhere.
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Affiliation(s)
- Geme Urge Dori
- Department of Experimental Medicine and Public Health, University of Camerino, Camerino, Italy ; School of Medical Laboratory Sciences, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
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Winthrop KL, Furtado JM, Silva JC, Resnikoff S, Lansingh VC. River blindness: an old disease on the brink of elimination and control. J Glob Infect Dis 2011; 3:151-5. [PMID: 21731302 PMCID: PMC3125028 DOI: 10.4103/0974-777x.81692] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
For decades, onchocerciasis (or river blindness) was one of the most common infectious causes of blindness in the world. Primarily an infection of Africa, with limited distribution in the new world, disease due to the nematode Onchocerca volvulus is rapidly diminishing as a result of large public health campaigns targeting at risk populations in Africa and the Americas. Existing and newly-developed treatment strategies offer the chance to eliminate onchocercal ocular morbidity in some parts of the world. This article reviews these treatment strategies, current clinical and epidemiologic aspects of onchocerciasis, and the next steps toward elimination.
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Affiliation(s)
- Kevin L Winthrop
- Casey Eye Institute, Division of International Ophthalmology, Oregon Health and Science University, Portland, Oregon
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