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Targeting Ergosterol biosynthesis in Leishmania donovani: essentiality of sterol 14 alpha-demethylase. PLoS Negl Trop Dis 2015; 9:e0003588. [PMID: 25768284 PMCID: PMC4359151 DOI: 10.1371/journal.pntd.0003588] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/03/2015] [Indexed: 01/14/2023] Open
Abstract
Leishmania protozoan parasites (Trypanosomatidae family) are the causative agents of cutaneous, mucocutaneous and visceral leishmaniasis worldwide. While these diseases are associated with significant morbidity and mortality, there are few adequate treatments available. Sterol 14alpha-demethylase (CYP51) in the parasite sterol biosynthesis pathway has been the focus of considerable interest as a novel drug target in Leishmania. However, its essentiality in Leishmania donovani has yet to be determined. Here, we use a dual biological and pharmacological approach to demonstrate that CYP51 is indispensable in L. donovani. We show via a facilitated knockout approach that chromosomal CYP51 genes can only be knocked out in the presence of episomal complementation and that this episome cannot be lost from the parasite even under negative selection. In addition, we treated wild-type L. donovani and CYP51-deficient strains with 4-aminopyridyl-based inhibitors designed specifically for Trypanosoma cruzi CYP51. While potency was lower than in T. cruzi, these inhibitors had increased efficacy in parasites lacking a CYP51 allele compared to complemented parasites, indicating inhibition of parasite growth via a CYP51-specific mechanism and confirming essentiality of CYP51 in L. donovani. Overall, these results provide support for further development of CYP51 inhibitors for the treatment of visceral leishmaniasis. Visceral leishmaniasis is the second most lethal parasitic infection after malaria. Other forms of leishmaniasis also cause significant morbidity. However, there are few treatments available, and many cause severe side effects or are associated with the development of resistance. A key difference between mammalian cells and Leishmania parasites is the type of sterol in their membranes: while mammalian cell membranes contain cholesterol, Leishmania parasites use ergosterol. There has therefore been considerable interest in developing inhibitors of sterol biosynthesis pathways to target Leishmania parasites. Sterol 14alpha-demethylase (CYP51) is one of the enzymes in the sterol biosynthesis pathway, and the target of significant drug development research in Leishmania. Here we use a double approach to determine whether this gene is essential in Leishmania donovani, the causative agent of visceral leishmaniasis. We demonstrate via gene knockout and drug targeting approaches that loss or inhibition of CYP51 inhibits L. donovani growth. These results validate CYP51 as a drug target in L. donovani and support further work to develop CYP51-directed therapies for visceral leishmaniasis.
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Undurraga EA, Betancourt-Cravioto M, Ramos-Castañeda J, Martínez-Vega R, Méndez-Galván J, Gubler DJ, Guzmán MG, Halstead SB, Harris E, Kuri-Morales P, Tapia-Conyer R, Shepard DS. Economic and disease burden of dengue in Mexico. PLoS Negl Trop Dis 2015; 9:e0003547. [PMID: 25786225 PMCID: PMC4364886 DOI: 10.1371/journal.pntd.0003547] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 01/17/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Dengue imposes a substantial economic and disease burden in most tropical and subtropical countries. Dengue incidence and severity have dramatically increased in Mexico during the past decades. Having objective and comparable estimates of the economic burden of dengue is essential to inform health policy, increase disease awareness, and assess the impact of dengue prevention and control technologies. METHODS AND FINDINGS We estimated the annual economic and disease burden of dengue in Mexico for the years 2010-2011. We merged multiple data sources, including a prospective cohort study; patient interviews and macro-costing from major hospitals; surveillance, budget, and health data from the Ministry of Health; WHO cost estimates; and available literature. We conducted a probabilistic sensitivity analysis using Monte Carlo simulations to derive 95% certainty levels (CL) for our estimates. Results suggest that Mexico had about 139,000 (95%CL: 128,000-253,000) symptomatic and 119 (95%CL: 75-171) fatal dengue episodes annually on average (2010-2011), compared to an average of 30,941 symptomatic and 59 fatal dengue episodes reported. The annual cost, including surveillance and vector control, was US$170 (95%CL: 151-292) million, or $1.56 (95%CL: 1.38-2.68) per capita, comparable to other countries in the region. Of this, $87 (95%CL: 87-209) million or $0.80 per capita (95%CL: 0.62-1.12) corresponds to illness. Annual disease burden averaged 65 (95%CL: 36-99) disability-adjusted life years (DALYs) per million population. Inclusion of long-term sequelae, co-morbidities, impact on tourism, and health system disruption during outbreaks would further increase estimated economic and disease burden. CONCLUSION With this study, Mexico joins Panama, Puerto Rico, Nicaragua, and Thailand as the only countries or areas worldwide with comprehensive (illness and preventive) empirical estimates of dengue burden. Burden varies annually; during an outbreak, dengue burden may be significantly higher than that of the pre-vaccine level of rotavirus diarrhea. In sum, Mexico's potential economic benefits from dengue control would be substantial.
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Affiliation(s)
- Eduardo A. Undurraga
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | | | - José Ramos-Castañeda
- Instituto Nacional de Salud Pública, Cuernavaca, Mexico
- Center for Tropical Diseases, University of Texas-Medical Branch, Galveston, Texas, United States of America
| | - Ruth Martínez-Vega
- Instituto Nacional de Salud Pública, Cuernavaca, Mexico
- Organización Latinoamericana para el Fomento de la Investigación en Salud, Bucaramanga, Colombia
| | | | | | | | - Scott B. Halstead
- Pediatric Dengue Vaccine Initiative, Rockville, Maryland, United States of America
| | - Eva Harris
- University of California, Berkeley, Berkeley, California, United States of America
| | | | | | - Donald S. Shepard
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
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653
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Nouvellet P, Cucunubá ZM, Gourbière S. Ecology, evolution and control of Chagas disease: a century of neglected modelling and a promising future. ADVANCES IN PARASITOLOGY 2015; 87:135-91. [PMID: 25765195 DOI: 10.1016/bs.apar.2014.12.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
More than 100 years after its formal description, Chagas disease remains a major public health concern in Latin America with a yearly burden of 430,000 Disability-Adjusted Life Years (DALYs). The aetiological agent, a protozoan named Trypanosoma cruzi, is mainly transmitted to mammalian hosts by triatomine vectors. Multiple species of mammals and triatomines can harbour and transmit the parasite, and the feeding range of triatomine species typically includes many noncompetent hosts. Furthermore, the transmission of the pathogen can occur via several routes including the typical vector's faeces, but also oral, congenital and blood transfusion routes. These ecological and epidemiological complexities of the disease have hindered many control initiatives. In such a context, mathematical models provide invaluable tools to explore and understand the dynamics of T. cruzi transmission, and to design, optimize and monitor the efficacy of control interventions. We intend here to provide the first review of the mathematical models of Chagas disease, focussing on how they have contributed to our understanding of (1) the population dynamics and control of triatomine vectors, and (2) the epidemiology of T. cruzi infections. We also aim at suggesting promising lines of modelling that could further improve our understanding of the ecology, evolution, and control of the disease.
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Affiliation(s)
- Pierre Nouvellet
- Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Zulma M Cucunubá
- Grupo de Parasitología, Instituto Nacional de Salud, Colombia; Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Sébastien Gourbière
- Institut de Modélisation et d'Analyse en Géo-Environnements et Santé (IMAGES), Université de Perpignan Via Domitia, Perpignan, France
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654
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Marinho DS, Casas CNPR, Pereira CCDA, Leite IC. Health economic evaluations of visceral leishmaniasis treatments: a systematic review. PLoS Negl Trop Dis 2015; 9:e0003527. [PMID: 25723482 PMCID: PMC4344218 DOI: 10.1371/journal.pntd.0003527] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 01/09/2015] [Indexed: 11/19/2022] Open
Abstract
Visceral leishmaniasis (VL) is a severe form of the leishmaniasis-disease complex. Its importance to public health relies on its high fatality rate in non-treated cases, the socio-economic impact related to its morbidity, and its endemicity on different continents. The estimated burden of disease of VL varies from 1,969,000 to 2,357,000 Disability Adjusted Life Years (DALYs). VL is classified as a Neglected Tropical Disease (NTD), and is strongly related to poverty and its consequences. Visceral leishmaniasis calls for the development of cost-effective technologies for diagnosis and treatment. Visceral leishmaniasis (VL), also known as kala azar, is a neglected tropical disease caused by parasitic protozoa of the genus Leishmania. VL is related to poverty and its consequences, which leads to its status of neglected disease. For that reason, cost-effective forms of diagnoses and treatment are very important and still needed. This research aimed at a better understanding of the publications about the technologies currently available, from the standpoint of their economic value. For that purpose, we conducted a systematic review of the literature in order to identify the papers that conducted economic evaluations of technologies used in VL. We initially retrieved 107 articles, which were inspected according to specific guidelines for systematic reviews. After that process, 14 articles matched the inclusion criteria in our review. We classified those studies according to the type of economic evaluation they made, and the methodology used in each one. We found evaluations about a variety of technologies, but the studies were geographically concentrated in Asia, more specifically in India. This concentration is not good because the disease also affects other continents and it is not possible to transfer the economic evaluation from one country or epidemiologic scenario to another.
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Affiliation(s)
- Daniel S. Marinho
- Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
- Escola Nacional de Saúde Pública Sérgio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
- National Institute for Science and Technology on Innovation on Neglected Diseases (INCT/IDN), Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
| | - Carmen N. P. R. Casas
- Centro de Desenvolvimento Tecnológico em Saúde, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
- National Institute for Science and Technology on Innovation on Neglected Diseases (INCT/IDN), Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
| | | | - Iuri C. Leite
- Escola Nacional de Saúde Pública Sérgio Arouca, Fundação Oswaldo Cruz, Rio de Janeiro, Brasil
- * E-mail:
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655
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Severini C, Menegon M. Resistance to antimalarial drugs: An endless world war against Plasmodium that we risk losing. J Glob Antimicrob Resist 2015; 3:58-63. [PMID: 27873670 DOI: 10.1016/j.jgar.2015.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/23/2015] [Accepted: 02/02/2015] [Indexed: 10/23/2022] Open
Abstract
The objective of this review was to describe the 'state of the art' of Plasmodium falciparum resistance to the main antimalarial drugs. A brief note on Plasmodium vivax is also included. Resistance of P. falciparum to the various antimalarials has a long history of hits and misses. During the last 60 years, the pace at which this parasite has developed resistance to antimalarial drugs has exceeded the pace at which new drugs have been developed. In the last decade, the introduction of artemisinin-based combination therapies (ACTs) as a first-line drug treatment for non-complicated P. falciparum malaria had led to extraordinary results in disease control, especially in sub-Saharan Africa. However, the emergence and spread of resistance to artemisinin in Southeast Asia jeopardise these results. In conclusion, the possible spread of artemisinin resistance in Africa should be considered as an epochal disaster.
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Affiliation(s)
- Carlo Severini
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.
| | - Michela Menegon
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, Rome, Italy
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656
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Matt J, Duchêne M. Molecular and biochemical characterization of Entamoeba histolytica fructokinase. Parasitol Res 2015; 114:1939-47. [PMID: 25700717 PMCID: PMC4412284 DOI: 10.1007/s00436-015-4383-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 02/05/2015] [Indexed: 11/23/2022]
Abstract
Entamoeba histolytica is the causative agent of amoebic dysentery and liver abscess. The medium for its axenic culture contains glucose as energy source, and we addressed the question whether E. histolytica can also use fructose instead. As the amoebic hexokinases do not phosphorylate fructose, a separate fructokinase is essential. The genome project revealed a single candidate gene encoding an E. histolytica homolog of bacterial fructokinases. This gene was cloned, and the recombinant enzyme had a magnesium-dependent fructose 6-kinase activity (EC 2.7.1.4) with a Km for fructose of 0.156 mM and a Vmax of 131 U/mg protein. Recombinant fructokinase also showed a much weaker mannokinase activity, but no activity with glucose or galactose. The amoebae could be switched from glucose to fructose medium without any detectable consequence on doubling time. Fructokinase messenger RNA (mRNA) was modestly but significantly upregulated in amoebae switched to fructose medium as well as in fructose-adapted E. histolytica.
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Affiliation(s)
- Julia Matt
- Institute of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, 1090, Vienna, Austria
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657
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Fontecha GA, García K, Rueda MM, Sosa-Ochoa W, Sánchez AL, Leiva B. A PCR-RFLP method for the simultaneous differentiation of three Entamoeba species. Exp Parasitol 2015; 151-152:80-3. [PMID: 25680279 DOI: 10.1016/j.exppara.2015.02.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 12/13/2022]
Abstract
Amoebiasis caused by Entamoeba histolytica continues to be one of the most common parasitic diseases in the developing world. Despite its relevance, due to the lack of accurate diagnostic methods, the true clinical and public health importance of this parasite remains uncertain. The aim of this study was to develop a new diagnostic tool to differentiate E.histolytica from the morphologically undistinguishable E.dispar and E.moshkovskii. We developed a specific, fast and simple PCR-RFLP method that was able to accurately differentiate experimentally-obtained restriction patterns from the three Entamoeba species. This new method could prove useful for clinical and epidemiological purposes.
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Affiliation(s)
- Gustavo A Fontecha
- Microbiology Research Institute, Microbiology School, National Autonomous University of Honduras (UNAH), Ciudad Universitaria, J1, 4th fl., Tegucigalpa, Honduras.
| | - Kimberly García
- Microbiology Research Institute, Microbiology School, National Autonomous University of Honduras (UNAH), Ciudad Universitaria, J1, 4th fl., Tegucigalpa, Honduras
| | - María Mercedes Rueda
- Microbiology Research Institute, Microbiology School, National Autonomous University of Honduras (UNAH), Ciudad Universitaria, J1, 4th fl., Tegucigalpa, Honduras
| | - Wilfredo Sosa-Ochoa
- Microbiology Research Institute, Microbiology School, National Autonomous University of Honduras (UNAH), Ciudad Universitaria, J1, 4th fl., Tegucigalpa, Honduras
| | - Ana Lourdes Sánchez
- Microbiology Research Institute, Microbiology School, National Autonomous University of Honduras (UNAH), Ciudad Universitaria, J1, 4th fl., Tegucigalpa, Honduras; Department of Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Byron Leiva
- Microbiology and Parasitology Department, Faculty of Medical Sciences, Infectious Diseases Research Center, UNAN-León, León, Nicaragua
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658
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Affiliation(s)
- Charles H. King
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
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659
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Quintana JF, Makepeace BL, Babayan SA, Ivens A, Pfarr KM, Blaxter M, Debrah A, Wanji S, Ngangyung HF, Bah GS, Tanya VN, Taylor DW, Hoerauf A, Buck AH. Extracellular Onchocerca-derived small RNAs in host nodules and blood. Parasit Vectors 2015; 8:58. [PMID: 25623184 PMCID: PMC4316651 DOI: 10.1186/s13071-015-0656-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/12/2015] [Indexed: 12/02/2022] Open
Abstract
Background microRNAs (miRNAs), a class of short, non-coding RNA can be found in a highly stable, cell-free form in mammalian body fluids. Specific miRNAs are secreted by parasitic nematodes in exosomes and have been detected in the serum of murine and dog hosts infected with the filarial nematodes Litomosoides sigmodontis and Dirofilaria immitis, respectively. Here we identify extracellular, parasite-derived small RNAs associated with Onchocerca species infecting cattle and humans. Methods Small RNA libraries were prepared from total RNA extracted from the nodule fluid of cattle infected with Onchocerca ochengi as well as serum and plasma from humans infected with Onchocerca volvulus in Cameroon and Ghana. Parasite-derived miRNAs were identified based on the criteria that sequences unambiguously map to hairpin structures in Onchocerca genomes, do not align to the human genome and are not present in European control serum. Results A total of 62 mature miRNAs from 52 distinct pre-miRNA candidates were identified in nodule fluid from cattle infected with O. ochengi of which 59 are identical in the genome of the human parasite O. volvulus. Six of the extracellular miRNAs were also identified in sequencing analyses of serum and plasma from humans infected with O. volvulus. Based on sequencing analysis the abundance levels of the parasite miRNAs in serum or plasma range from 5 to 127 reads/per million total host miRNA reads identified, comparable to our previous analyses of Schistosoma mansoni and L. sigmodontis miRNAs in serum. All six of the O. volvulus miRNAs identified have orthologs in other filarial nematodes and four were identified in the serum of mice infected with L. sigmodontis. Conclusions We have identified parasite-derived miRNAs associated with onchocerciasis in cattle and humans. Our results confirm the conserved nature of RNA secretion by diverse nematodes. Additional species-specific small RNAs from O. volvulus may be present in serum based on the novel miRNA sequences identified in the nodule fluid. In our analyses comparison to European control serum illuminates the scope for false-positives, warranting caution in criteria that should be applied to identification of biomarkers of infection. Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-0656-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juan F Quintana
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, West Mains Road, Edinburgh, UK.
| | - Benjamin L Makepeace
- Institute of Infection and Global Health, University of Liverpool, Liverpool, Merseyside, UK.
| | - Simon A Babayan
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
| | - Alasdair Ivens
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, West Mains Road, Edinburgh, UK.
| | - Kenneth M Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany.
| | - Mark Blaxter
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, West Mains Road, Edinburgh, UK.
| | - Alexander Debrah
- Kumasi Centre for Collaborative Research (KCCR) and Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
| | - Samuel Wanji
- Research Foundation in Tropical Diseases and Environment and University of Buea, Buea, Cameroon.
| | - Henrietta F Ngangyung
- Institut de Recherche Agricole pour le Développement, Regional Centre of Wakwa, Ngaoundéré, Cameroon.
| | - Germanus S Bah
- Institut de Recherche Agricole pour le Développement, Regional Centre of Wakwa, Ngaoundéré, Cameroon.
| | | | - David W Taylor
- Institute of Infection and Global Health, University of Liverpool, Liverpool, Merseyside, UK. .,Division of Pathway Medicine, School for Biomedical Sciences, University of Edinburgh, Little France, Edinburgh, UK.
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital of Bonn, Bonn, Germany.
| | - Amy H Buck
- Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, West Mains Road, Edinburgh, UK.
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660
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Leila Srour M, Marck KW, Baratti-Mayer D. Noma: neglected, forgotten and a human rights issue. Int Health 2015; 7:149-50. [PMID: 25609756 DOI: 10.1093/inthealth/ihv001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/23/2014] [Indexed: 11/14/2022] Open
Abstract
Noma, an orofacial gangrene and opportunistic infection, affects primarily malnourished children living in extreme poverty. Neglected, forgotten, unknown by most health workers, noma results in death, disfigurement and disability of some of the world's most vulnerable children. Noma is a biological indicator of multiple human rights violations, including the right to food. International support and national attention in countries with noma are lacking. The end of neglect of noma can lead to the elimination of this horrific childhood disease.
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Affiliation(s)
| | - Klaas W Marck
- Dutch Noma Foundation, De Pôlle 24, 9084BT Goutum, The Netherlands
| | - Denise Baratti-Mayer
- GESNOMA (Geneva Study Group on Noma), Service of Plastic and Reconstructive Surgery, Geneva University Hospitals, Geneva, Switzerland
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661
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Shi PY, Smith PW, Diagana TT. Therapeutics for Neglected Infectious Diseases: Progress and Challenge. ACS Infect Dis 2015; 1:76-8. [PMID: 27620147 DOI: 10.1021/id500043r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Pei-Yong Shi
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, 05-01 Chromos, Singapore 138670
| | - Paul W. Smith
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, 05-01 Chromos, Singapore 138670
| | - Thierry T. Diagana
- Novartis Institute for Tropical Diseases, 10 Biopolis Road, 05-01 Chromos, Singapore 138670
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662
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Seid CA, Curti E, Jones RM, Hudspeth E, Rezende W, Pollet J, Center L, Versteeg L, Pritchard S, Musiychuk K, Yusibov V, Hotez PJ, Bottazzi ME. Expression, purification, and characterization of the Necator americanus aspartic protease-1 (Na-APR-1 (M74)) antigen, a component of the bivalent human hookworm vaccine. Hum Vaccin Immunother 2015; 11:1474-88. [PMID: 25905574 PMCID: PMC4514214 DOI: 10.1080/21645515.2015.1036207] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/13/2015] [Accepted: 03/27/2015] [Indexed: 11/08/2022] Open
Abstract
Over 400 million people living in the world's poorest developing nations are infected with hookworms, mostly of the genus Necator americanus. A bivalent human hookworm vaccine composed of the Necator americanus Glutathione S-Transferase-1 (Na-GST-1) and the Necator americanus Aspartic Protease-1 (Na-APR-1 (M74)) is currently under development by the Sabin Vaccine Institute Product Development Partnership (Sabin PDP). Both monovalent vaccines are currently in Phase 1 trials. Both Na-GST-1 and Na-APR-1 antigens are expressed as recombinant proteins. While Na-GST-1 was found to express with high yields in Pichia pastoris, the level of expression of Na-APR-1 in this host was too low to be suitable for a manufacturing process. When the tobacco plant Nicotiana benthamiana was evaluated as an expression system, acceptable levels of solubility, yield, and stability were attained. Observed expression levels of Na-APR-1 (M74) using this system are ∼300 mg/kg. Here we describe the achievements and obstacles encountered during process development as well as characterization and stability of the purified Na-APR-1 (M74) protein and formulated vaccine. The expression, purification and analysis of purified Na-APR-1 (M74) protein obtained from representative 5 kg reproducibility runs performed to qualify the Na-APR-1 (M74) production process is also presented. This process has been successfully transferred to a pilot plant and a 50 kg scale manufacturing campaign under current Good Manufacturing Practice (cGMP) has been performed. The 50 kg run has provided a sufficient amount of protein to support the ongoing hookworm vaccine development program of the Sabin PDP.
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Affiliation(s)
- Christopher A Seid
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Elena Curti
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - R Mark Jones
- Fraunhofer Center for Molecular Biotechnology; Newark, DE, USA
| | - Elissa Hudspeth
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Wanderson Rezende
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Jeroen Pollet
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Lori Center
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Leroy Versteeg
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
| | - Sonya Pritchard
- Fraunhofer Center for Molecular Biotechnology; Newark, DE, USA
| | | | - Vidadi Yusibov
- Fraunhofer Center for Molecular Biotechnology; Newark, DE, USA
| | - Peter J Hotez
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
- Department of Biology; Baylor University; Waco, TX, USA
| | - Maria Elena Bottazzi
- Departments of Pediatrics and Molecular Virology and Microbiology; National School of Tropical Medicine; Baylor College of Medicine; Houston, TX, USA
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development; Houston, TX, USA
- Department of Biology; Baylor University; Waco, TX, USA
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Selenium-Functionalized Molecules (SeFMs) as Potential Drugs and Nutritional Supplements. TOPICS IN MEDICINAL CHEMISTRY 2015. [DOI: 10.1007/7355_2015_87] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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664
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Integrated parasite management: path to sustainable control of fishborne trematodes in aquaculture. Trends Parasitol 2015; 31:8-15. [DOI: 10.1016/j.pt.2014.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 10/21/2014] [Accepted: 10/21/2014] [Indexed: 01/17/2023]
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665
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Hotez PJ. The medical biochemistry of poverty and neglect. Mol Med 2014; 20 Suppl 1:S31-6. [PMID: 25549231 DOI: 10.2119/molmed.2014.00169] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/10/2014] [Indexed: 11/06/2022] Open
Affiliation(s)
- Peter J Hotez
- National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, Texas, United States of America Department of Biology, Baylor University, Waco, Texas, United States of America James A. Baker III Institute for Public Policy, Rice University, Houston, Texas, United States of America
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Salim N, Schindler T, Abdul U, Rothen J, Genton B, Lweno O, Mohammed AS, Masimba J, Kwaba D, Abdulla S, Tanner M, Daubenberger C, Knopp S. Enterobiasis and strongyloidiasis and associated co-infections and morbidity markers in infants, preschool- and school-aged children from rural coastal Tanzania: a cross-sectional study. BMC Infect Dis 2014; 14:644. [PMID: 25486986 PMCID: PMC4271451 DOI: 10.1186/s12879-014-0644-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/20/2014] [Indexed: 11/24/2022] Open
Abstract
Background There is a paucity of data pertaining to the epidemiology and public health impact of Enterobius vermicularis and Strongyloides stercoralis infections. We aimed to determine the extent of enterobiasis, strongyloidiasis, and other helminth infections and their association with asymptomatic Plasmodium parasitaemia, anaemia, nutritional status, and blood cell counts in infants, preschool-aged (PSAC), and school-aged children (SAC) from rural coastal Tanzania. Methods A total of 1,033 children were included in a cross-sectional study implemented in the Bagamoyo district in 2011/2012. Faecal samples were examined for intestinal helminth infections using a broad set of quality controlled methods. Finger-prick blood samples were subjected to filariasis and Plasmodium parasitaemia testing and full blood cell count examination. Weight, length/height, and/or mid-upper arm circumference were measured and the nutritional status determined in accordance with age. Results E. vermicularis infections were found in 4.2% of infants, 16.7%, of PSAC, and 26.3% of SAC. S. stercoralis infections were detected in 5.8%, 7.5%, and 7.1% of infants, PSAC, and SAC, respectively. Multivariable regression analyses revealed higher odds of enterobiasis in children of all age-groups with a reported anthelminthic treatment history over the past six months (odds ratio (OR): 2.15; 95% confidence interval (CI): 1.22 - 3.79) and in SAC with a higher temperature (OR: 2.21; CI: 1.13 - 4.33). Strongyloidiasis was associated with eosinophilia (OR: 2.04; CI: 1.20-3.48) and with Trichuris trichiura infections (OR: 4.13; CI: 1.04-16.52) in children of all age-groups, and with asymptomatic Plasmodium parasitaemia (OR: 13.03; CI: 1.34 - 127.23) in infants. None of the investigated helminthiases impacted significantly on the nutritional status and anaemia, but moderate asymptomatic Plasmodium parasitaemia was a strong predictor for anaemia in children aged older than two years (OR: 2.69; 95% CI: 1.23 – 5.86). Conclusions E. vermicularis and S. stercoralis infections were moderately prevalent in children from rural coastal Tanzania. Our data can contribute to inform yet missing global burden of disease and prevalence estimates for strongyloidiasis and enterobiasis. The association between S stercoralis and asymptomatic Plasmodium parasitaemia found here warrants further comprehensive investigations. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0644-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nahya Salim
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. .,Department of Pediatrics and Child Health, Muhimbili University Health and Allied Sciences, Dar es Salaam, United Republic of Tanzania. .,Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Tobias Schindler
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. .,University of Basel, Basel, Switzerland. .,Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Ummi Abdul
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - Julian Rothen
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. .,University of Basel, Basel, Switzerland. .,Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Blaise Genton
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Department of Ambulatory Care and Community Medicine, Infectious Disease Service, Lausanne University Hospital, Lausanne, Switzerland.
| | - Omar Lweno
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - Alisa S Mohammed
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - John Masimba
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - Denis Kwaba
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - Salim Abdulla
- Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania.
| | - Marcel Tanner
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland.
| | - Claudia Daubenberger
- University of Basel, Basel, Switzerland. .,Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland.
| | - Stefanie Knopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. .,University of Basel, Basel, Switzerland. .,Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, Natural History Museum, London, United Kingdom.
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667
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Hürlimann E, Houngbedji CA, Yapi RB, Ndri PB, Silué KD, Soro G, Kouamé FN, Fürst T, Utzinger J, N'Goran EK, Raso G. Health-related quality of life among school children with parasitic infections: findings from a national cross-sectional survey in Côte d'Ivoire. PLoS Negl Trop Dis 2014; 8:e3287. [PMID: 25474579 PMCID: PMC4256278 DOI: 10.1371/journal.pntd.0003287] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 09/22/2014] [Indexed: 12/28/2022] Open
Abstract
Background Parasitic infections are still of considerable public health relevance, notably among children in low- and middle-income countries. Measures to assess the magnitude of ill-health in infected individuals, however, are debated and patient-based proxies through generic health-related quality of life (HrQoL) instruments are among the proposed strategies. Disability estimates based on HrQoL are still scarce and conflicting, and hence, there is a need to strengthen the current evidence-base. Methodology Between November 2011 and February 2012, a national school-based cross-sectional survey was conducted in Côte d'Ivoire. Children underwent parasitological and clinical examination to assess infection status with Plasmodium and helminth species and clinical parameters, and responded to a questionnaire interview incorporating sociodemographic characteristics, self-reported morbidity, and HrQoL. Validity analysis of the HrQoL instrument was performed, assessing floor and ceiling effects, internal consistency, and correlation with morbidity scores. Multivariate regression models were applied to identify significant associations between HrQoL and children's parasitic infection and clinical status. Principal Findings Parasitological examination of 4,848 children aged 5–16 years revealed Plasmodium spp., hookworm, Schistosoma haematobium, Schistosoma mansoni, Ascaris lumbricoides, and Trichuris trichiura prevalences of 75.0%, 17.2%, 5.7%, 3.7%, 1.8%, and 1.3%, respectively. Anemic children showed a significant 1-point reduction in self-rated HrQoL on a scale from 0 to 100, whereas no significant negative association between HrQoL and parasite infection was observed. The 12-item HrQoL questionnaire proofed useful, as floor and ceiling effects were negligible, internally consistent (Cronbach's alpha = 0.71), and valid, as revealed by significant negative correlations and associations with children's self-reported and clinically assessed morbidity. Conclusions/Significance Our results suggest that HrQoL tools are not sufficiently sensitive to assess subtle morbidities due to parasitic infection in Ivorian school-aged children. However, more advanced morbid sequelae (e.g., anemia), were measurable by the instrument's health construct. Further investigations on health impacts of parasitic infection among school-aged children and refinement of generic HrQoL questionnaires are warranted. Infectious diseases like malaria and parasitic worms affect hundreds of millions of people, and impact physical and cognitive development of children in Africa, Asia, and the Americas. Over the past 20 years, it was debated how the magnitude of ill-health due to these conditions should be assessed. One proposed strategy was to include patient-based ratings of wellbeing by administration of health-related quality of life (HrQoL) questionnaires. In order to provide new evidence on disability from parasitic infections, we conducted HrQoL interviews with children aged 5–16 years from 92 schools across Côte d'Ivoire. Children were examined for parasitic infections and clinical signs like anemia, malnutrition, and organ enlargement. We compared the self-rated HrQoL of infected and non-infected children and also considered their sociodemographic background. We could not identify lowered HrQoL in infected children, but we found that children with anemia reported a 1-point lower score on a 100-point HrQoL scale in comparison with their non-anemic counterparts. We consider our HrQoL questionnaire as useful and valid, but would recommend its further testing and development in few purposefully selected settings. Further investigation of disability induced by malaria and parasitic worm infections is warranted.
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Affiliation(s)
- Eveline Hürlimann
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
| | - Clarisse A. Houngbedji
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
| | - Richard B. Yapi
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Prisca B. Ndri
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Unité de Formation et de Recherche Sciences de la Nature, Université Nangui Abrogoua, Abidjan, Côte d'Ivoire
| | - Kigbafori D. Silué
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Gotianwa Soro
- Programme National de Santé Scolaire et Universitaire, Abidjan, Côte d'Ivoire
| | - Ferdinand N. Kouamé
- Programme National de Santé Scolaire et Universitaire, Abidjan, Côte d'Ivoire
| | - Thomas Fürst
- Centre for Health Policy, Imperial College London, London, United Kingdom
- Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Eliézer K. N'Goran
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- Unité de Formation et de Recherche Biosciences, Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Giovanna Raso
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- Département Environnement et Santé, Centre Suisse de Recherches Scientifiques en Côte d'Ivoire, Abidjan, Côte d'Ivoire
- * E-mail:
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Spatial and temporal distribution of soil-transmitted helminth infection in sub-Saharan Africa: a systematic review and geostatistical meta-analysis. THE LANCET. INFECTIOUS DISEASES 2014; 15:74-84. [PMID: 25486852 DOI: 10.1016/s1473-3099(14)71004-7] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Interest is growing in predictive risk mapping for neglected tropical diseases (NTDs), particularly to scale up preventive chemotherapy, surveillance, and elimination efforts. Soil-transmitted helminths (hookworm, Ascaris lumbricoides, and Trichuris trichiura) are the most widespread NTDs, but broad geographical analyses are scarce. We aimed to predict the spatial and temporal distribution of soil-transmitted helminth infections, including the number of infected people and treatment needs, across sub-Saharan Africa. METHODS We systematically searched PubMed, Web of Knowledge, and African Journal Online from inception to Dec 31, 2013, without language restrictions, to identify georeferenced surveys. We extracted data from household surveys on sources of drinking water, sanitation, and women's level of education. Bayesian geostatistical models were used to align the data in space and estimate risk of with hookworm, A lumbricoides, and T trichiura over a grid of roughly 1 million pixels at a spatial resolution of 5 × 5 km. We calculated anthelmintic treatment needs on the basis of WHO guidelines (treatment of all school-aged children once per year where prevalence in this population is 20-50% or twice per year if prevalence is greater than 50%). FINDINGS We identified 459 relevant survey reports that referenced 6040 unique locations. We estimate that the prevalence of hookworm, A lumbricoides, and T trichiura among school-aged children from 2000 onwards was 16·5%, 6·6%, and 4·4%. These estimates are between 52% and 74% lower than those in surveys done before 2000, and have become similar to values for the entire communities. We estimated that 126 million doses of anthelmintic treatments are required per year. INTERPRETATION Patterns of soil-transmitted helminth infection in sub-Saharan Africa have changed and the prevalence of infection has declined substantially in this millennium, probably due to socioeconomic development and large-scale deworming programmes. The global control strategy should be reassessed, with emphasis given also to adults to progress towards local elimination. FUNDING Swiss National Science Foundation and European Research Council.
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669
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Turner HC, Walker M, French MD, Blake IM, Churcher TS, Basáñez MG. Neglected tools for neglected diseases: mathematical models in economic evaluations. Trends Parasitol 2014; 30:562-70. [PMID: 25455565 DOI: 10.1016/j.pt.2014.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/01/2014] [Accepted: 10/07/2014] [Indexed: 12/27/2022]
Abstract
Despite many current interventions against neglected tropical diseases (NTDs) being highly cost-effective, new strategies are needed to reach the WHO's control and elimination goals. Here we argue for the importance of incorporating economic evaluations of new strategies in decisions regarding resource allocation. Such evaluation should ideally be conducted using dynamic transmission models that capture inherent nonlinearities in transmission and the indirect benefits ('herd effects') of interventions. A systematic review of mathematical models that have been used for economic analysis of interventions against the ten NTDs covered by the London Declaration reveals that only 16 out of 49 studies used dynamic transmission models, highlighting a fundamental--but addressable--gap in the evaluation of interventions against NTDs.
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Affiliation(s)
- Hugo C Turner
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; 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.
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; 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
| | - Michael D French
- 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; Schistosomiasis Control Initiative, 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
| | - Isobel M Blake
- 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; MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, London W2 1PG, UK
| | - Thomas S Churcher
- 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
| | - María-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine (St Mary's Campus), Imperial College London, Norfolk Place, London W2 1PG, UK; 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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670
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Tomczyk S, Deribe K, Brooker SJ, Clark H, Rafique K, Knopp S, Utzinger J, Davey G. Association between footwear use and neglected tropical diseases: a systematic review and meta-analysis. PLoS Negl Trop Dis 2014; 8:e3285. [PMID: 25393620 PMCID: PMC4230915 DOI: 10.1371/journal.pntd.0003285] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 09/22/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The control of neglected tropical diseases (NTDs) has primarily focused on preventive chemotherapy and case management. Less attention has been placed on the role of ensuring access to adequate water, sanitation, and hygiene and personal preventive measures in reducing exposure to infection. Our aim was to assess whether footwear use was associated with a lower risk of selected NTDs. METHODOLOGY We conducted a systematic review and meta-analysis to assess the association between footwear use and infection or disease for those NTDs for which the route of transmission or occurrence may be through the feet. We included Buruli ulcer, cutaneous larva migrans (CLM), leptospirosis, mycetoma, myiasis, podoconiosis, snakebite, tungiasis, and soil-transmitted helminth (STH) infections, particularly hookworm infection and strongyloidiasis. We searched Medline, Embase, Cochrane, Web of Science, CINAHL Plus, and Popline databases, contacted experts, and hand-searched reference lists for eligible studies. The search was conducted in English without language, publication status, or date restrictions up to January 2014. Studies were eligible for inclusion if they reported a measure of the association between footwear use and the risk of each NTD. Publication bias was assessed using funnel plots. Descriptive study characteristics and methodological quality of the included studies were summarized. For each study outcome, both outcome and exposure data were abstracted and crude and adjusted effect estimates presented. Individual and summary odds ratio (OR) estimates and corresponding 95% confidence intervals (CIs) were calculated as a measure of intervention effect, using random effects meta-analyses. PRINCIPAL FINDINGS Among the 427 studies screened, 53 met our inclusion criteria. Footwear use was significantly associated with a lower odds of infection of Buruli ulcer (OR=0.15; 95% CI: 0.08-0.29), CLM (OR=0.24; 95% CI: 0.06-0.96), tungiasis (OR=0.42; 95% CI: 0.26-0.70), hookworm infection (OR=0.48; 95% CI: 0.37-0.61), any STH infection (OR=0.57; 95% CI: 0.39-0.84), strongyloidiasis (OR=0.56; 95% CI: 0.38-0.83), and leptospirosis (OR=0.59; 95% CI: 0.37-0.94). No significant association between footwear use and podoconiosis (OR=0.63; 95% CI: 0.38-1.05) was found and no data were available for mycetoma, myiasis, and snakebite. The main limitations were evidence of heterogeneity and poor study quality inherent to the observational studies included. CONCLUSIONS/SIGNIFICANCE Our results show that footwear use was associated with a lower odds of several different NTDs. Access to footwear should be prioritized alongside existing NTD interventions to ensure a lasting reduction of multiple NTDs and to accelerate their control and elimination. PROTOCOL REGISTRATION PROSPERO International prospective register of systematic reviews CRD42012003338.
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Affiliation(s)
- Sara Tomczyk
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Kebede Deribe
- Brighton & Sussex Medical School, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Simon J. Brooker
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hannah Clark
- Brighton & Sussex Medical School, Brighton, United Kingdom
| | - Khizar Rafique
- Brighton & Sussex Medical School, Brighton, United Kingdom
| | - Stefanie Knopp
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, Natural History Museum, London, United Kingdom
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Jürg Utzinger
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Gail Davey
- Brighton & Sussex Medical School, Brighton, United Kingdom
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671
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Affiliation(s)
- Karl F Hoffmann
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth SY23 3DA, UK.
| | - Paul J Brindley
- Department of Microbiology, Immunology and Tropical Medicine and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington, DC 20037, USA
| | - Matthew Berriman
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
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Shepard DS, Undurraga EA, Betancourt-Cravioto M, Guzmán MG, Halstead SB, Harris E, Mudin RN, Murray KO, Tapia-Conyer R, Gubler DJ. Approaches to refining estimates of global burden and economics of dengue. PLoS Negl Trop Dis 2014; 8:e3306. [PMID: 25412506 PMCID: PMC4238988 DOI: 10.1371/journal.pntd.0003306] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 10/01/2014] [Indexed: 11/24/2022] Open
Abstract
Dengue presents a formidable and growing global economic and disease burden, with around half the world's population estimated to be at risk of infection. There is wide variation and substantial uncertainty in current estimates of dengue disease burden and, consequently, on economic burden estimates. Dengue disease varies across time, geography and persons affected. Variations in the transmission of four different viruses and interactions among vector density and host's immune status, age, pre-existing medical conditions, all contribute to the disease's complexity. This systematic review aims to identify and examine estimates of dengue disease burden and costs, discuss major sources of uncertainty, and suggest next steps to improve estimates. Economic analysis of dengue is mainly concerned with costs of illness, particularly in estimating total episodes of symptomatic dengue. However, national dengue disease reporting systems show a great diversity in design and implementation, hindering accurate global estimates of dengue episodes and country comparisons. A combination of immediate, short-, and long-term strategies could substantially improve estimates of disease and, consequently, of economic burden of dengue. Suggestions for immediate implementation include refining analysis of currently available data to adjust reported episodes and expanding data collection in empirical studies, such as documenting the number of ambulatory visits before and after hospitalization and including breakdowns by age. Short-term recommendations include merging multiple data sources, such as cohort and surveillance data to evaluate the accuracy of reporting rates (by health sector, treatment, severity, etc.), and using covariates to extrapolate dengue incidence to locations with no or limited reporting. Long-term efforts aim at strengthening capacity to document dengue transmission using serological methods to systematically analyze and relate to epidemiologic data. As promising tools for diagnosis, vaccination, vector control, and treatment are being developed, these recommended steps should improve objective, systematic measures of dengue burden to strengthen health policy decisions.
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Affiliation(s)
- Donald S. Shepard
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | - Eduardo A. Undurraga
- Schneider Institutes for Health Policy, Heller School, Brandeis University, Waltham, Massachusetts, United States of America
| | | | | | - Scott B. Halstead
- Dengue Vaccine Initiative, Rockville, Maryland, United States of America
| | - Eva Harris
- University of California, Berkeley, California, United States of America
| | | | - Kristy O. Murray
- Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, United States of America
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673
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Prevalence of intestinal parasitic infections among children under five years of age with emphasis on Schistosoma mansoni in Wonji Shoa Sugar Estate, Ethiopia. PLoS One 2014; 9:e109793. [PMID: 25296337 PMCID: PMC4190315 DOI: 10.1371/journal.pone.0109793] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 09/08/2014] [Indexed: 11/23/2022] Open
Abstract
Intestinal parasite infections are major public health problems of children in developing countries causing undernutrition, anemia, intestinal obstruction and mental and physical growth retardation. This study was conducted to assess the prevalence of intestinal helminthic infections among children under five years of age with emphasis on Schistosoma mansoni in Wonji Shoa Sugar Estate, Ethiopia. A cross-sectional parasitological survey was conducted in under-five children living in Wonji Shoa Sugar Estate Ethiopia, April, 2013. Stool samples were collected and examined for intestinal parasites using single Kato-Katz and single Sodium acetate-acetic acid-formalin (SAF) solution concentration methods. Out of 374 children examined using single Kato-Katz and single SAF-concentration methods, 24.3% were infected with at least one intestinal parasite species. About 10.4%, 8.8%, 4.6%, 2.9%, 1.6% and 0.8% of the children were infected with Hymenolepis nana, Schistosoma mansoni, Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis and hookworm, respectively. Prevalence of double, triple and quadruple intestinal helminthic infection was 6.4%, 0.54% and 1.1%, respectively. A significant increase in prevalence of S. mansoni (8.3% versus 3.2%) and T. trichiura (2.7% versus 0.5%) infection was observed when determined via the single Kato-Katz method compared to the prevalence of the parasites determined via the single SAF-concentration method. On the other hand, the single SAF-concentration method (9.1%) revealed a significantly higher prevalence of H. nana infection than the single Kato-Katz (1.6%) does. In conclusion, intestinal helminths infections particularly S. mansoni and H. nana were prevalent in under-five children of Wonji Shoa Sugar Estate. Including praziquantel treatment in the deworming program as per the World Health Organization guidelines would be vital to reduce the burden of these diseases in areas where S. mansoni and H. nana infections are prevalent among under-fives. Kato-Katz can be used in estimating the prevalence of S. mansoni and other helminth infections.
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Ramamoorthi R, Graef KM, Dent J. WIPO Re:Search: Accelerating anthelmintic development through cross-sector partnerships. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2014; 4:220-5. [PMID: 25516832 PMCID: PMC4266808 DOI: 10.1016/j.ijpddr.2014.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
WIPO Re:Search leverages pharmaceutical assets to advance anthelmintic research. BIO Ventures for Global Health (BVGH) facilitates collaborations and capacity building. Novartis scientists trained a Cameroonian researcher on advanced biochemistry skills. Researchers from Canada and Cameroon partnered to discover onchocerciasis drugs. Natural products were screened against schistosomes and soil-transmitted helminths.
Neglected tropical diseases (NTDs), malaria, and tuberculosis have a devastating effect on an estimated 1.6 billion people worldwide. The World Intellectual Property Organization (WIPO) Re:Search consortium accelerates the development of new drugs, vaccines, and diagnostics for these diseases by connecting the assets and resources of pharmaceutical companies, such as compound libraries and expertise, to academic or nonprofit researchers with novel product discovery or development ideas. As the WIPO Re:Search Partnership Hub Administrator, BIO Ventures for Global Health (BVGH) fields requests from researchers, identifies Member organizations able to fulfill these requests, and helps forge mutually beneficial collaborations. Since its inception in October 2011, WIPO Re:Search membership has expanded to more than 90 institutions, including leading pharmaceutical companies, universities, nonprofit research institutions, and product development partnerships from around the world. To date, WIPO Re:Search has facilitated over 70 research agreements between Consortium Members, including 11 collaborations focused on anthelmintic drug discovery.
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Affiliation(s)
- Roopa Ramamoorthi
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, WA 98109, United States
| | - Katy M Graef
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, WA 98109, United States
| | - Jennifer Dent
- BIO Ventures for Global Health, 401 Terry Avenue North, Seattle, WA 98109, United States
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Hotez PJ. Could nitazoxanide be added to other essential medicines for integrated neglected tropical disease control and elimination? PLoS Negl Trop Dis 2014; 8:e2758. [PMID: 24675990 PMCID: PMC3967954 DOI: 10.1371/journal.pntd.0002758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Peter J. Hotez
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Departments of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America
- James A. Baker III Institute for Public Policy, Rice University, Houston, Texas, United States of America
- * E-mail:
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