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Pietrzak D, Łuczak JW, Wiśniewski M. Beyond Tradition: Exploring Cutting-Edge Approaches for Accurate Diagnosis of Human Filariasis. Pathogens 2024; 13:447. [PMID: 38921745 PMCID: PMC11206659 DOI: 10.3390/pathogens13060447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/16/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
Filariasis is recognised as a global public health threat, particularly in tropical and subtropical regions. It is caused by infection with a nematode parasite of the superfamily Filarioidea, including Wuchereria bancrofti, Brugia malayi, Onchocerca volvulus, and Onchocerca lupi. Three main types of filariasis have been classified: lymphatic filariasis, subcutaneous filariasis, and serous cavity filariasis. The symptoms exhibited by individuals afflicted with filariasis are diverse and contingent upon several variables, including the species of parasite, the host's health and immune response, and the stage of infection. While many classical parasitological techniques are considered indispensable tools for the diagnosis of parasitic infections in humans, alternative methods are being sought due to their limitations. Novel tests based on host-parasite interactions offer a rapid, simple, sensitive, and specific diagnostic tool in comparison to traditional parasitological methods. This article presents methods developed in the 21st century for the diagnosis of filariasis caused by invasion from W. bancrofti, B. malayi, O. volvulus, and O. lupi, as well as techniques that are currently in use. The development of modern diagnostic methods based on molecular biology constitutes a significant advancement in the fight against filariasis.
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Affiliation(s)
- Damian Pietrzak
- Division of Parasitology and Parasitic Diseases, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences—SGGW, 02-786 Warsaw, Poland;
| | - Julia Weronika Łuczak
- Faculty of Animal Breeding, Bioengineering and Conservation, Warsaw University of Life Sciences—SGGW, 02-786 Warsaw, Poland;
| | - Marcin Wiśniewski
- Division of Parasitology and Parasitic Diseases, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences—SGGW, 02-786 Warsaw, Poland;
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Nancy K, Lillian W, Wilkinson M, Claire M, Luna K, Dorcas W, Rosemary G, Japheth L, Christine I, Emily W, Jim K. Optimization of a Loop-Mediated Isothermal Amplification Assay as a Point-of-Care Tool for the Detection of Wuchereria bancrofti in Human Blood in Tana River Delta, Kenya. J Parasitol Res 2021; 2021:6650870. [PMID: 34367688 PMCID: PMC8337116 DOI: 10.1155/2021/6650870] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 06/28/2021] [Accepted: 07/07/2021] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Accurate detection of filarial parasites in humans and vectors is essential for the implementation and evaluation of Global and National Programs to eliminate lymphatic filariasis. Immunological methods to detect infection are available; however, cross-reactivity issues have been reported in most of them. Nucleic acid-based molecular assays offer high levels of specificity and sensitivity and can be used to detect the infections. METHODS In this study, we evaluated loop-mediated isothermal amplification (LAMP) tests to amplify Wuchereria bancrofti DNA in patients' blood. The amplicons were tested by both pH-sensitive dyes for enhanced visual detection and agarose gel electrophoresis. A closed-tube LAMP assay was also evaluated. Cohen's Kappa statistics was used for statistical analysis of the assays. 125 patients consented for blood sampling which were used for clinical analysis of LAMP assays with the PCR method used as the "gold standard." RESULTS The sensitivity of the evaluated Wuchereria bancrofti LAMP was 92.3%, with a specificity of 97.3% and kappa statistics value of 0.84, which is in a strong agreement. CONCLUSION In this study, LAMP assays coupled with fluorescence dye detection have been found to be suitable for diagnosis and monitoring of Wuchereria bancrofti infections in the Kenyan population.
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Affiliation(s)
- Kinyatta Nancy
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Wambua Lillian
- School of Biological Science, University of Nairobi, 30772-00100, Nairobi, Kenya
| | - Mutahi Wilkinson
- School of Biological Science, University of Nairobi, 30772-00100, Nairobi, Kenya
| | - Mugasa Claire
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University Kampala, 7062 Kampala, Uganda
| | - Kamau Luna
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Wachira Dorcas
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Githae Rosemary
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Lusweti Japheth
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Ichugu Christine
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Waigi Emily
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
| | - Kagai Jim
- Kenya Medical Research Institute, Centre for Biotechnology Research and Development, P.O. Box 54840-00200, Nairobi, Kenya
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Antibody-Based Protective Immunity against Helminth Infections: Antibody Phage Display Derived Antibodies against BmR1 Antigen. Int J Mol Sci 2017; 18:ijms18112376. [PMID: 29165352 PMCID: PMC5713345 DOI: 10.3390/ijms18112376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/25/2017] [Accepted: 11/02/2017] [Indexed: 12/18/2022] Open
Abstract
Helminth parasite infections are significantly impacting global health, with more than two billion infections worldwide with a high morbidity rate. The complex life cycle of the nematodes has made host immune response studies against these parasites extremely difficult. In this study, we utilized two phage antibody libraries; the immune and naïve library were used to identify single chain fragment variable (scFv) clones against a specific filarial antigen (BmR1). The V-gene analysis of isolated scFv clones will help shed light on preferential VDJ gene segment usage against the filarial BmR1 antigen in healthy and infected states. The immune library showed the usage of both lambda and kappa light chains. However, the naïve library showed preferential use of the lambda family with different amino acid distributions. The binding characteristics of the scFv clones identified from this work were analyzed by immunoassay and immunoaffinity pull down of BmR1. The work highlights the antibody gene usage pattern of a naïve and immune antibody library against the same antigen as well as the robust nature of the enriched antibodies for downstream applications.
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Irish SR, Stevens WMB, Derua YA, Walker T, Cameron MM. Comparison of Methods for Xenomonitoring in Vectors of Lymphatic Filariasis in Northeastern Tanzania. Am J Trop Med Hyg 2015; 93:983-9. [PMID: 26350454 PMCID: PMC4703286 DOI: 10.4269/ajtmh.15-0234] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 07/14/2015] [Indexed: 11/07/2022] Open
Abstract
Monitoring Wuchereria bancrofti infection in mosquitoes (xenomonitoring) can play an important role in determining when lymphatic filariasis has been eliminated, or in focusing control efforts. As mosquito infection rates can be low, a method for collecting large numbers of mosquitoes is necessary. Gravid traps collected large numbers of Culex quinquefasciatus in Tanzania, and a collection method that targets mosquitoes that have already fed could result in increased sensitivity in detecting W. bancrofti-infected mosquitoes. The aim of this experiment was to test this hypothesis by comparing U.S. Centers for Disease Control and Prevention (CDC) light traps with CDC gravid traps in northeastern Tanzania, where Cx. quinquefasciatus is a vector of lymphatic filariasis. After an initial study where small numbers of mosquitoes were collected, a second study collected 16,316 Cx. quinquefasciatus in 60 gravid trap-nights and 240 light trap-nights. Mosquitoes were pooled and tested for presence of W. bancrofti DNA. Light and gravid traps collected similar numbers of mosquitoes per trap-night, but the physiological status of the mosquitoes was different. The estimated infection rate in mosquitoes collected in light traps was considerably higher than in mosquitoes collected in gravid traps, so light traps can be a useful tool for xenomonitoring work in Tanzania.
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Affiliation(s)
- Seth R Irish
- London School of Hygiene and Tropical Medicine, London, United Kingdom; National Institute for Medical Research, Muheza, Tanzania
| | - William M B Stevens
- London School of Hygiene and Tropical Medicine, London, United Kingdom; National Institute for Medical Research, Muheza, Tanzania
| | - Yahya A Derua
- London School of Hygiene and Tropical Medicine, London, United Kingdom; National Institute for Medical Research, Muheza, Tanzania
| | - Thomas Walker
- London School of Hygiene and Tropical Medicine, London, United Kingdom; National Institute for Medical Research, Muheza, Tanzania
| | - Mary M Cameron
- London School of Hygiene and Tropical Medicine, London, United Kingdom; National Institute for Medical Research, Muheza, Tanzania
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Shrinking the lymphatic filariasis map: update on diagnostic tools for mapping and transmission monitoring. Parasitology 2014; 141:1912-7. [PMID: 25225828 DOI: 10.1017/s0031182014001231] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Lymphatic filariasis (LF), which is highly endemic in 73 countries worldwide, is targeted for elimination by 2020. The strategy for achieving this goal is based on 4 sequential programmatic steps: mapping, Mass drug administration (MDA) implementation, post-MDA surveillance and verification of LF elimination. All 4 stages of the implementation process are dependent on the availability of user friendly and highly sensitive rapid diagnostic tools. By the end of 2012, 59 countries had completed mapping for LF and Eritrea was the only country yet to start the process. Rolling out new diagnostic tools to facilitate the mapping process will enable an accelerated shrinking of the LF map to zero endemic countries by 2020. When the Global Programme to Eliminate Lymphatic Filariasis was launched in 2000, diagnostic tools for LF were limited to clinical examination, detection of microfilaria (MF) by microscopy in night blood samples and detection of antibodies to native-antigen preparations. There has been a significant improvement in the traditional LF diagnostic methods in recent years and some new tools are now available. This paper provides an update on the human diagnostic tests available for LF and their current applications as tools in mapping and transmission monitoring. The values of entomological indicators and parasite detection and speciation methods applied to vector populations are also discussed.
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Rebollo MP, Bockarie MJ. Toward the elimination of lymphatic filariasis by 2020: treatment update and impact assessment for the endgame. Expert Rev Anti Infect Ther 2014; 11:723-31. [PMID: 23879610 DOI: 10.1586/14787210.2013.811841] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lymphatic filariasis (LF) is an important public health problem endemic in 73 countries, where it is a major cause of acute and chronic morbidity and a significant impediment to socioeconomic development. It is targeted for elimination by 2020, through preventive chemotherapy using albendazole in combination with either ivermectin or diethylcarbamazine citrate. Preventive chemotherapy enables the regular and coordinated administration of safe, single-dose medications delivered through mass drug administration (MDA). Many countries are now scaling down MDA activities after achieving 100% geographic coverage and instituting monitoring and evaluation procedures to establish the impact of several consecutive rounds of MDA and determine if transmission has been interrupted. At the same time, countries yet to initiate MDA for elimination of LF will adopt improved mapping and coverage assessment protocols to accelerate the efforts for achieving global elimination by 2020. This review provides an update on treatment for LF and describes the current global status of the elimination efforts, transmission control processes and strategies for measuring impact and continuing surveillance after MDA has ceased.
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Affiliation(s)
- Maria P Rebollo
- Center for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
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Fischer P, Bonow I, Supali T, Rückert P, Rahmah N. Detection of filaria-specific IgG4antibodies and filarial DNA, for the screening of blood spots forBrugia timori. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 99:53-60. [PMID: 15701256 DOI: 10.1179/136485905x13339] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The establishment of simple, sensitive and specific tools for the diagnosis of brugian lymphatic filariasis is a prerequisite for a successful intervention to control the disease. In the simple and rapid Brugia Rapid (BR) test, an immunochromatographic dipstick is used to detect IgG(4) antibodies that are reactive with a recombinant Brugia malayi antigen. When sera from 109 individuals with Brugia microfilaraemias (12 with B. malayi and 97 with B. timori) were investigated using the BR test, all were found positive. In contrast, all of the 150 sera from individuals with Onchocerca volvulus or Mansonella infections investigated were found negative in BR tests. Some unwelcome cross-reactions were observed, however, with sera from individuals infected with Wuchereria bancrofti (three of 12 test-positive) and Dirofilaria (one of nine test-positive). In an attempt to facilitate sample collection and detect any cross-reactions, the BR dipstick was used to screen blood spots, that had been allowed to dry on filter paper, for B. timori microfilariae, before the dipstick-positive samples were tested with a PCR-based assay. Of the 66 individuals so tested, 37 (56%) were found positive by the BR test used on dry blood spots and eight (22%) by the filtration of fresh blood samples. Only nine of the 37 dipstick-positive samples were found PCR-positive. The combined use of BR tests and PCR-based assays, for testing blood spots in areas where brugian filariasis is endemic, appears to be a promising method not only for post-treatment monitoring but also for the certification activities planned within the framework of the Global Programme to Eliminate Lymphatic Filariasis.
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Affiliation(s)
- P Fischer
- Department of Helminthology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, D-20359 Hamburg, Germany.
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Korte RL, Fontes G, Camargo JDSAA, Rocha EMMD, Araújo EACD, Oliveira MZD, Santos RVD, Camargo LMA. Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control. Rev Soc Bras Med Trop 2013; 46:214-20. [DOI: 10.1590/0037-8682-1708-2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 02/14/2013] [Indexed: 05/27/2023] Open
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Diagnosis of brugian filariasis by loop-mediated isothermal amplification. PLoS Negl Trop Dis 2012; 6:e1948. [PMID: 23272258 PMCID: PMC3521703 DOI: 10.1371/journal.pntd.0001948] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 10/25/2012] [Indexed: 11/19/2022] Open
Abstract
In this study we developed and evaluated a Brugia Hha I repeat loop-mediated isothermal amplification (LAMP) assay for the rapid detection of Brugia genomic DNA. Amplification was detected using turbidity or fluorescence as readouts. Reactions generated a turbidity threshold value or a clear visual positive within 30 minutes using purified genomic DNA equivalent to one microfilaria. Similar results were obtained using DNA isolated from blood samples containing B. malayi microfilariae. Amplification was specific to B. malayi and B. timori, as no turbidity was observed using DNA from the related filarial parasites Wuchereria bancrofti, Onchocerca volvulus or Dirofilaria immitis, or from human or mosquito. Furthermore, the assay was most robust using a new strand-displacing DNA polymerase termed Bst 2.0 compared to wild-type Bst DNA polymerase, large fragment. The results indicate that the Brugia Hha I repeat LAMP assay is rapid, sensitive and Brugia-specific with the potential to be developed further as a field tool for diagnosis and mapping of brugian filariasis. Brugian filariasis is a debilitating neglected tropical disease caused by infection with the filarial parasites Brugia malayi or Brugia timori. Adult worms live in the lymphatic system and produce large numbers of microfilariae that predominantly circulate in the blood at night. Bloodsucking mosquitoes spread the disease by ingesting microfilariae that develop into infective stage larvae in the insect. In rural areas, diagnosis still relies largely on microscopic examination of night blood and morphological assessment of stained microfilariae. Loop-mediated isothermal amplification (LAMP) is a technique that can amplify DNA with high specificity, sensitivity and rapidity under isothermal conditions. The operational simplicity, versatility and low-cost of the technique make it particularly appealing for use in diagnosis and geographical mapping of neglected tropical diseases. In the present study, we have developed and evaluated a Brugia Hha I repeat LAMP assay for the rapid detection of B. malayi and B. timori genomic DNA. The results indicate that the Brugia Hha I repeat LAMP diagnostic assay is sensitive and rapid, detecting a single microfilariae in blood within 30 minutes, and Brugia-specific. The test has the potential to be developed further as a field tool for use in the implementation and management of mass drug administration programs for brugian filariasis.
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Henry-Halldin CN, Nadesakumaran K, Keven JB, Zimmerman AM, Siba P, Mueller I, Hetzel MW, Kazura JW, Thomsen E, Reimer LJ, Zimmerman PA. Multiplex assay for species identification and monitoring of insecticide resistance in Anopheles punctulatus group populations of Papua New Guinea. Am J Trop Med Hyg 2012; 86:140-51. [PMID: 22232465 PMCID: PMC3247123 DOI: 10.4269/ajtmh.2012.11-0503] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 09/24/2011] [Indexed: 11/07/2022] Open
Abstract
Anopheles punctulatus sibling species (An. punctulatus s.s., Anopheles koliensis, and Anopheles farauti species complex [eight cryptic species]) are principal vectors of malaria and filariasis in the Southwest Pacific. Given significant effort to reduce malaria and filariasis transmission through insecticide-treated net distribution in the region, effective strategies to monitor evolution of insecticide resistance among An. punctulatus sibling species is essential. Mutations in the voltage-gated sodium channel (VGSC) gene have been associated with knock-down resistance (kdr) to pyrethroids and DDT in malarious regions. By examining VGSC sequence polymorphism we developed a multiplex assay to differentiate wild-type versus kdr alleles and query intron-based polymorphisms that enable simultaneous species identification. A survey including mosquitoes from seven Papua New Guinea Provinces detected no kdr alleles in any An. punctulatus species. Absence of VGSC sequence introgression between species and evidence of geographic separation within species suggests that kdr must be monitored in each An. punctulatus species independently.
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Affiliation(s)
- Cara N. Henry-Halldin
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio; Papua New Guinea Institute of Medical Research, Madang, MADANG, Papua New Guinea; Papua New Guinea Institute of Medical Research, Goroka, EASTERN HIGHLANDS, Papua New Guinea; School of Population Health, University of Queensland, Brisbane, Australia
| | - Kogulan Nadesakumaran
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio; Papua New Guinea Institute of Medical Research, Madang, MADANG, Papua New Guinea; Papua New Guinea Institute of Medical Research, Goroka, EASTERN HIGHLANDS, Papua New Guinea; School of Population Health, University of Queensland, Brisbane, Australia
| | | | | | | | | | | | | | | | | | - Peter A. Zimmerman
- Center for Global Health and Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio; Papua New Guinea Institute of Medical Research, Madang, MADANG, Papua New Guinea; Papua New Guinea Institute of Medical Research, Goroka, EASTERN HIGHLANDS, Papua New Guinea; School of Population Health, University of Queensland, Brisbane, Australia
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Ashton RA, Kyabayinze DJ, Opio T, Auma A, Edwards T, Matwale G, Onapa A, Brooker S, Kolaczinski JH. The impact of mass drug administration and long-lasting insecticidal net distribution on Wuchereria bancrofti infection in humans and mosquitoes: an observational study in northern Uganda. Parasit Vectors 2011; 4:134. [PMID: 21756371 PMCID: PMC3158553 DOI: 10.1186/1756-3305-4-134] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 07/15/2011] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) in Uganda is caused by Wuchereria bancrofti and transmitted by anopheline mosquitoes. The mainstay of elimination has been annual mass drug administration (MDA) with ivermectin and albendazole, targeted to endemic districts, but has been sporadic and incomplete in coverage. Vector control could potentially contribute to reducing W. bancrofti transmission, speeding up progress towards elimination. To establish whether the use of long-lasting insecticidal nets (LLINs) can contribute towards reducing transmission of W. bancrofti in a setting with ongoing MDA, a study was conducted in an area of Uganda highly endemic for both LF and malaria. Baseline parasitological and entomological assessments were conducted in 2007, followed by high-coverage LLIN distribution. Net use and entomological surveys were carried out after one year, and final parasitological and entomological evaluations were conducted in 2010. Three rounds of MDA had taken place before the study commenced, with a further three rounds completed during the course of the study. RESULTS In 2007, rapid mapping indicated 22.3% of schoolchildren were W. bancrofti antigen positive, and a baseline survey during the same year found age-adjusted microfilaraemia prevalence was 3.7% (95% confidence interval (CI): 2.6-5.3%). In 2010, age-adjusted microfilaraemia prevalence had fallen to 0.4%, while antigenaemia rates were 0.2% in children < 5 years and 6.0% in ≥ 5 years. In 2010, universal coverage of mosquito nets in a household was found to be protective against W. bancrofti antigen (odds ratio = 0.44, 95% CI: 0.22-0.89). Prevalence of W. bancrofti larvae in anopheline mosquitoes had decreased significantly between the 2007 and 2010 surveys, but there was an apparent increase in vector densities. CONCLUSION A marked reduction in W. bancrofti infection and infectivity in humans was observed in the study area, where both MDA and LLINs were used to reduce transmission. The extent to which LLINs contributed to this decline is equivocal, however. Further work investigating the impact of vector control on anopheline-transmitted LF in an endemic area not benefitting from MDA would be valuable to determine the effect of such interventions on their own.
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Affiliation(s)
- Ruth A Ashton
- Malaria Consortium Africa, Kampala, Uganda
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Tom Opio
- District Health Office, Dokolo, Uganda
| | - Anna Auma
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | - Tansy Edwards
- MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Gabriel Matwale
- Vector Control Division, Ministry of Health, Kampala, Uganda
| | | | - Simon Brooker
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Malaria Public Health & Epidemiology Group, Kenya Medical Research Institute-Wellcome Trust Research Programme, Nairobi, Kenya
| | - Jan H Kolaczinski
- Malaria Consortium Africa, Kampala, Uganda
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
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Abstract
Since 1977, >2000 research papers described attempts to detect, identify and/or quantify parasites, or disease organisms carried by ecto-parasites, using DNA-based tests and 148 reviews of the topic were published. Despite this, only a few DNA-based tests for parasitic diseases are routinely available, and most of these are optional tests used occasionally in disease diagnosis. Malaria, trypanosomiasis, toxoplasmosis, leishmaniasis and cryptosporidiosis diagnosis may be assisted by DNA-based testing in some countries, but there are very few cases where the detection of veterinary parasites is assisted by DNA-based tests. The diagnoses of some bacterial (e.g. lyme disease) and viral diseases (e.g. tick borne encephalitis) which are transmitted by ecto-parasites more commonly use DNA-based tests, and research developing tests for these species makes up almost 20% of the literature. Other important uses of DNA-based tests are for epidemiological and risk assessment, quality control for food and water, forensic diagnosis and in parasite biology research. Some DNA-based tests for water-borne parasites, including Cryptosporidium and Giardia, are used in routine checks of water treatment, but forensic and food-testing applications have not been adopted in routine practice. Biological research, including epidemiological research, makes the widest use of DNA-based diagnostics, delivering enhanced understanding of parasites and guidelines for managing parasitic diseases. Despite the limited uptake of DNA-based tests to date, there is little doubt that they offer great potential to not only detect, identify and quantify parasites, but also to provide further information important for the implementation of parasite control strategies. For example, variant sequences within species of parasites and other organisms can be differentiated by tests in a manner similar to genetic testing in medicine or livestock breeding. If an association between DNA sequence and phenotype has been demonstrated, then qualities such as drug resistance, strain divergence, virulence, and origin of isolates could be inferred by DNA-based tests. No such tests are in clinical or commercial use in parasitology and few tests are available for other organisms. Why have DNA-based tests not had a bigger impact in veterinary and human medicine? To explore this question, technological, biological, economic and sociological factors must be considered. Additionally, a realistic expectation of research progress is needed. DNA-based tests could enhance parasite management in many ways, but patience, persistence and dedication will be needed to achieve this goal.
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Njenga SM, Mwandawiro CS, Wamae CN, Mukoko DA, Omar AA, Shimada M, Bockarie MJ, Molyneux DH. Sustained reduction in prevalence of lymphatic filariasis infection in spite of missed rounds of mass drug administration in an area under mosquito nets for malaria control. Parasit Vectors 2011; 4:90. [PMID: 21612649 PMCID: PMC3125382 DOI: 10.1186/1756-3305-4-90] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 05/25/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was established by the World Health Organisation (WHO) in 2000 with the goal of eliminating lymphatic filariasis (LF) as a public health problem globally by 2020. Mass drug administration (MDA) of antifilarial drugs is the principal strategy recommended for global elimination. Kenya launched a National Programme for Elimination of Lymphatic Filariasis (NPELF) in Coast Region in 2002. During the same year a longitudinal research project to monitor trends of LF infection during MDA started in a highly endemic area in Malindi District. High coverage of insecticide treated nets (ITNs) in the coastal region has been associated with dramatic decline in hospital admissions due to malaria; high usage of ITNs is also expected to have an impact on LF infection, also transmitted by mosquitoes. RESULTS Four rounds of MDA with diethylcarbamazine citrate (DEC) and albendazole were given to 8 study villages over an 8-year period. Although annual MDA was not administered for several years the overall prevalence of microfilariae declined significantly from 20.9% in 2002 to 0.9% in 2009. Similarly, the prevalence of filarial antigenaemia declined from 34.6% in 2002 to 10.8% in 2009. All the examined children born since the start of the programme were negative for filarial antigen in 2009. CONCLUSIONS Despite the fact that the study villages missed MDA in some of the years, significant reductions in infection prevalence and intensity were observed at each survey. More importantly, there were no rebounds in infection prevalence between treatment rounds. However, because of confounding variables such as insecticide-treated bed nets (ITNs), it is difficult to attribute the reduction to MDA alone as ITNs can lead to a significant reduction in exposure to filariasis vectors. The results indicate that national LF elimination programmes should be encouraged to continue provision of MDA albeit constraints that may lead to missing of MDA in some years.
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Affiliation(s)
- Sammy M Njenga
- Kenya Medical Research Institute (KEMRI), Mbagathi Road, Nairobi, Kenya
| | | | - C Njeri Wamae
- Kenya Medical Research Institute (KEMRI), Mbagathi Road, Nairobi, Kenya
- Kenya Methodist University, Meru, Kenya
| | | | - Anisa A Omar
- Ministry of Public Health and Sanitation, Nairobi, Kenya
| | - Masaaki Shimada
- Kenya Medical Research Institute (KEMRI), Mbagathi Road, Nairobi, Kenya
- Nagasaki University Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Moses J Bockarie
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
| | - David H Molyneux
- Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Liverpool, UK
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Manguin S, Bangs M, Pothikasikorn J, Chareonviriyaphap T. Review on global co-transmission of human Plasmodium species and Wuchereria bancrofti by Anopheles mosquitoes. INFECTION GENETICS AND EVOLUTION 2010; 10:159-77. [DOI: 10.1016/j.meegid.2009.11.014] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 11/16/2009] [Accepted: 11/16/2009] [Indexed: 10/20/2022]
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Erickson SM, Fischer K, Weil GJ, Christensen BM, Fischer PU. Distribution of Brugia malayi larvae and DNA in vector and non-vector mosquitoes: implications for molecular diagnostics. Parasit Vectors 2009; 2:56. [PMID: 19922607 PMCID: PMC2781795 DOI: 10.1186/1756-3305-2-56] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 11/17/2009] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of this study was to extend prior studies of molecular detection of Brugia malayi DNA in vector (Aedes aegypti- Liverpool) and non-vector (Culex pipiens) mosquitoes at different times after ingestion of infected blood. Results Parasite DNA was detected over a two week time course in 96% of pooled thoraces of vector mosquitoes. In contrast, parasite DNA was detected in only 24% of thorax pools from non-vectors; parasite DNA was detected in 56% of midgut pools and 47% of abdomen pools from non-vectors. Parasite DNA was detected in vectors in the head immediately after the blood meal and after 14 days. Parasite DNA was also detected in feces and excreta of the vector and non-vector mosquitoes which could potentially confound results obtained with field samples. However, co-housing experiments failed to demonstrate transfer of parasite DNA from infected to non-infected mosquitoes. Parasites were also visualized in mosquito tissues by immunohistololgy using an antibody to the recombinant filarial antigen Bm14. Parasite larvae were detected consistently after mf ingestion in Ae. aegypti- Liverpool. Infectious L3s were seen in the head, thorax and abdomen of vector mosquitoes 14 days after Mf ingestion. In contrast, parasites were only detected by histology shortly after the blood meal in Cx. pipiens, and these were not labeled by the antibody. Conclusion This study provides new information on the distribution of filarial parasites and parasite DNA in vector and non-vector mosquitoes. This information should be useful for those involved in designing and interpreting molecular xenomonitoring studies.
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Affiliation(s)
- Sara M Erickson
- Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, St Louis, Missouri, USA.
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Pedersen EM, Stolk WA, Laney SJ, Michael E. The role of monitoring mosquito infection in the Global Programme to Eliminate Lymphatic Filariasis. Trends Parasitol 2009; 25:319-27. [PMID: 19559649 DOI: 10.1016/j.pt.2009.03.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 03/09/2009] [Accepted: 03/27/2009] [Indexed: 11/26/2022]
Abstract
In addition to monitoring infection in the human host, there is also a need to assess larval infection in the vector mosquito population to evaluate the success of interventions for eliminating lymphatic filariasis transmission from endemic communities. Here, we review the current status of the available tools for quantifying vector infection and existing knowledge and evidence regarding potential infection thresholds for determining transmission interruption, to assess the potential for using vector infection monitoring as a tool for evaluating the success of filariasis treatment programmes.
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Affiliation(s)
- Erling M Pedersen
- DBL-Centre for Health Research and Development, Faculty of Life Sciences, University of Copenhagen, 1871 Frederiksberg, Denmark.
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A qPCR-based multiplex assay for the detection of Wuchereria bancrofti, Plasmodium falciparum and Plasmodium vivax DNA. Trans R Soc Trop Med Hyg 2008; 103:365-70. [PMID: 18801545 DOI: 10.1016/j.trstmh.2008.07.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 07/18/2008] [Accepted: 07/24/2008] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to develop real-time multiplex quantitative PCR (qPCR) assays for the simultaneous detection of Wuchereria bancrofti (Wb), Plasmodium falciparum (Pf) and P. vivax (Pv) in mosquitoes. We optimized the assays with purified DNA samples and then used these assays to test DNA samples isolated from Anopheles punctulatus mosquitoes collected in villages in Papua New Guinea where these infections are co-endemic. Singleplex assays detected Wb, Pf and Pv DNA in 32%, 19% and 15% of the mosquito pools, respectively, either alone or together with other parasites. Multiplex assay results agreed with singleplex results in most cases. Overall parasite DNA rates in mosquitoes, estimated by PoolScreen 2 software, for Wb, Pf and Pv were 4.9%, 2.7% and 2.1%, respectively. Parasite DNA rates were consistently higher in blood-fed mosquitoes than in host-seeking mosquitoes. Our results show that multiplex qPCR can be used to detect and estimate prevalence rates for multiple parasite species in arthropod vectors. We believe that multiplex molecular xenodiagnosis has great potential as a tool for non-invasively assessing the distribution and prevalence of vector-borne pathogens such as W. bancrofti and Plasmodium spp. in human populations and for assessing the impact of interventions aimed at controlling or eliminating these diseases.
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Distribution of filarial elephantiasis and hydrocele in Matara district, Sri Lanka, as reported by local leaders, and an immunological survey in areas with relatively high clinical rates. Parasitol Int 2008; 57:390-5. [DOI: 10.1016/j.parint.2008.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 11/17/2022]
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Boakye DA, Baidoo HA, Glah E, Brown C, Appawu M, Wilson MD. Monitoring lymphatic filariasis interventions: Adult mosquito sampling, and improved PCR - based pool screening method for Wuchereria bancrofti infection in Anopheles mosquitoes. FILARIA JOURNAL 2007; 6:13. [PMID: 18047647 PMCID: PMC2235849 DOI: 10.1186/1475-2883-6-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 11/29/2007] [Indexed: 12/01/2022]
Abstract
Background Monitoring and evaluation are essential to the successful implementation of mass drug administration programmes for LF elimination. Monitoring transmission when it is low requires both large numbers of mosquito vectors and sensitive methods for detecting Wuchereria bancrofti infections in them. PCR-based methods are preferred over classical dissections but the best protocol so far achieved detection of one L3 Wuchereria bancrofti larva in a pool of 35–50 Anopheles mosquitoes. It also lacks consistency and remains still a costly tool. Hence we decided to improve upon this to achieve detection in a pool of 100 or more by enhancing the quality of the template DNA. Prior to this we also evaluated three vector sampling methods in the context of numbers for monitoring. Methods Human landing, pyrethrium spray and light traps catches were conducted concurrently at sites in an LF endemic district in Ghana and the numbers obtained compared. Two DNA extraction methods; Bender buffer and phenol/chloroform purification, and DNAeasy Tissue kit (Quaigen Inc) were used on pools of 25, 50, 75 100 and 150 mosquitoes each seeded with one L3 or its quivalent amount of DNA. Then another set of extracted DNA by the two methods was subjected to Dynal bead purification method (using capture oligonucleotide primers). These were used as template DNA in PCR to amplify W. bancrofti sequences. The best PCR result was then evaluated in the field at five sites by comparing its results (infections per 1000 mosquitoes) with that of dissection of roughly equal samples sizes. Results The largest numbers of mosquitoes were obtained with the human landing catches at all the sites sampled. Although PCR detection of one L3 in pools of 25, 50 and 75 mosquitoes was consistent irrespective of the extraction method, that of one L3 in 100 was only achieved with the kit-extracted DNA/Dynal bead purification method. Infections were found at only two sites by both dissection and pool-screening being 14.3 and 19 versus 13.4 and 20.1 per 1000 Anopheles mosquitoes respectively, which were not statistically significant Discussion and conclusion HLC still remains the best option for sampling for the large numbers of mosquitoes required for monitoring transmission during MDA programmes, when vector population densities are high and classical indices of transmission are required. One – in – 100 detection is an improvement on previous PCR pool-screening methods, which in our opinion was a result of the introduction of the extra step of parasite DNA capture using Dynal/beads. As pool sizes increase the insects DNA will swamp parasite DNA making the latter less available for an efficient PCR, therefore we propose either additional steps of parasite DNA capture or real-time PCR to improve further the pool screening method. The study also attests also to the applicability of Katholi et al's algorithm developed for determining onchocerciasis prevalence in LF studies.
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Affiliation(s)
- Daniel A Boakye
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, P,O, Box LG 581, Legon, Accra, Ghana.
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Lenhart A, Eigege A, Kal A, Pam D, Miri ES, Gerlong G, Oneyka J, Sambo Y, Danboyi J, Ibrahim B, Dahl E, Kumbak D, Dakul A, Jinadu M, Umaru J, Richards FO, Lehmann T. Contributions of different mosquito species to the transmission of lymphatic filariasis in central Nigeria: implications for monitoring infection by PCR in mosquito pools. FILARIA JOURNAL 2007; 6:14. [PMID: 18047673 PMCID: PMC2228284 DOI: 10.1186/1475-2883-6-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 11/29/2007] [Indexed: 11/30/2022]
Abstract
Background Members of the Anopheles gambiae complex are important vectors of lymphatic filariasis (LF) in sub-Saharan Africa, but little is known about the relative contributions of all mosquitoes to lymphatic filariasis transmission in this area. Methods Over a 28 month period, mosquitoes were collected from 13 villages in Plateau and Nasarawa states in central Nigeria and dissected to determine W. bancrofti infection status. Wings and legs from a subset of the mosquitoes visually identified as A. gambiae s.l. were identified by PCR as either A. gambiae s.s. or A. arabiensis. Results A. gambiae s.s peaked in abundance during the rainy season while A. arabiensis predominated during drier parts of the year. Both species were found equally likely to be infected with the developing stages (L1-L3) of W. bancrofti (9.2% and 11.1%, respectively). Fewer A. funestus (1.1%, p < 0.001) were infected than A. gambiae s.l. Conclusion Understanding the relative contributions of morphologically indistinguishable species to LF transmission is essential if PCR is to be performed on mosquito pools. In the study area, the use of mosquito pools composed of A. gambiae sibling species would not be problematic, as both A. gambiae s.s. and A. arabiensis contribute equally to LF transmission.
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Rao RU, Weil GJ, Fischer K, Supali T, Fischer P. Detection of Brugia parasite DNA in human blood by real-time PCR. J Clin Microbiol 2006; 44:3887-93. [PMID: 16957038 PMCID: PMC1698366 DOI: 10.1128/jcm.00969-06] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Brugian filariasis (caused by the nematodes Brugia malayi and B. timori) is an important cause of disability in Southeast Asia. Improved diagnostic tests are needed for filariasis elimination programs (to identify areas of endemicity and to monitor progress) and for diagnosis of the disease in infected individuals. We have developed and evaluated two real-time PCR assays for detecting Brugia DNA in human blood and compared the results of these assays to those of "gold standard" assays. One assay uses a TaqMan probe (TaqM) to amplifiy a 320-bp "HhaI repeat" DNA sequence. The other assay uses a minor groove binding probe (MGB) and modified nucleotides in primers (Eclipse MGB) to amplify a 120-bp fragment of the HhaI repeat. This assay detects 22 copies of the target sequence, and it is more sensitive than the TaqM assay. Both assays were evaluated with human blood samples from two different areas of endemicity. The MGB assay was as sensitive as membrane filtration and microscopy for the detection of B. malayi infection in 57 blood samples recovered at night from patients in Sulawesi, Indonesia. The MGB assay also detected parasite DNA in 17 of 31 (55%) of microfilaria-negative day blood samples from these subjects. This test was more sensitive than the conventional and the TaqM PCRs (and was almost as sensitive as night blood membrane filtration) for the detection of infection in 52 blood samples recovered at night from individuals in an area of B. timori endemicity on Alor Island, Indonesia, where microfilaria-positive individuals had low densities after mass treatment. Thus, the Eclipse MGB real-time PCR assay is a sensitive means of detecting Brugia parasite DNA in human blood.
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Affiliation(s)
- Ramakrishna U Rao
- Department of Internal Medicine, Infectious Diseases Division, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8051, St. Louis, MO 63110, USA
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Supali T, Rahmah N, Djuardi Y, Sartono E, Rückert P, Fischer P. Detection of filaria-specific IgG4 antibodies using Brugia Rapid test in individuals from an area highly endemic for Brugia timori. Acta Trop 2004; 90:255-61. [PMID: 15099812 DOI: 10.1016/j.actatropica.2004.02.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2003] [Revised: 01/28/2004] [Accepted: 02/04/2004] [Indexed: 10/26/2022]
Abstract
The filarial parasite Brugia timori is of great public health importance in some islands of Eastern Indonesia. To establish a simple serological test for the identification and post-treatment monitoring of areas endemic for B. timori, a rapid immunochromatographic dipstick test (Brugia Rapid, BR) was evaluated on microfilaraemic and amicrofilaraemic individuals. This test is based on the detection of anti-filarial IgG4 antibodies that react with a recombinant Brugia malayi antigen (BmR1). In our study area on Alor island the prevalence of microfilaraemia was 26%. With the BR test, 100% of 196 sera from microfilaraemic persons and 76% of 563 sera from amicrofilaraemic persons, either symptomatic or asymptomatic, reacted positive. All 50 control sera from areas non-endemic for lymphatic filariasis gave negative BR test results. This study showed that the BR test can be also used to detect antibodies against B. timori. Due to the high prevalence of IgG4 antibodies as detected by the BR test (81%), no significant correlation with the prevalence of microfilaraemia could be detected within the endemic village. The BR test also shows great promise to be employed as a monitoring tool for B. timori in the framework of the Global Program to Eliminate Lymphatic Filariasis (GPELF).
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Affiliation(s)
- T Supali
- Department of Parasitology, Faculty of Medicine, University of Indonesia, Salemba 6, Jakarta 10430, Indonesia.
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Goodman DS, Orelus JN, Roberts JM, Lammie PJ, Streit TG. PCR and Mosquito dissection as tools to monitor filarial infection levels following mass treatment. FILARIA JOURNAL 2003; 2:11. [PMID: 12890288 PMCID: PMC169178 DOI: 10.1186/1475-2883-2-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2003] [Accepted: 07/07/2003] [Indexed: 11/23/2022]
Abstract
BACKGROUND: Entomological methods may provide important tools for monitoring the progress of lymphatic filariasis elimination programs. In this study, we compared dissection of the vector, Culex quinquefasciatus, with the polymerase chain reaction (PCR) to assess filarial infection levels in mosquitoes in the context of a lymphatic filariasis elimination program in Leogane, Haiti. METHODS: Mosquitoes were collected using gravid traps located in 4 sentinel communities with Wuchereria bancrofti microfilaria prevalence that ranged from 0.8% to 15.9%. Captured mosquitoes were divided between dissection, to enumerate W. bancrofti larvae (L1, L2, L3) and desiccation for later analysis by PCR. PCR was conducted on DNA extracts from pooled mosquitoes (1-15 pooled females) utilizing a competitive PCR system with primers specific for the Ssp I repeat. PCR products were analyzed with a hybridization ELISA using probes specific for a control sequence and the Ssp I repeat. RESULTS: The prevalence of mosquito infection with W. bancrofti ranged from 0%-3.66% by dissection (L1-L3) and point estimates of infection prevalence, as assayed by PCR, ranged from 0.25% - 9.16%. Following mass treatment, W. bancrofti infection prevalence dropped significantly as determined by PCR and dissection in 2 of the 4 sentinel sites (Leogane and Barrier Jeudi, P = 0.04 and P = 0.005, respectively). Although transmission declined in the other two sites, larval recoveries were low and these changes were not statistically significant. DISCUSSION: Our results suggest that a single round of mass treatment can have an impact on transmission of lymphatic filariasis. The use of entomologic methods as a tool to monitor filariasis programs and the statistical limitations of mosquito trapping are discussed.
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Affiliation(s)
- David S Goodman
- Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, Georgia, USA
| | | | - Jacquelin M Roberts
- Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, Georgia, USA
| | - Patrick J Lammie
- Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, Georgia, USA
| | - Thomas G Streit
- University of Notre Dame, Center for Tropical Disease Research & Training, Notre Dame, Indiana, USA
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Bockarie MJ, Tisch DJ, Kastens W, Alexander NDE, Dimber Z, Bockarie F, Ibam E, Alpers MP, Kazura JW. Mass treatment to eliminate filariasis in Papua New Guinea. N Engl J Med 2002; 347:1841-8. [PMID: 12466508 DOI: 10.1056/nejmoa021309] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND The global initiative to eradicate bancroftian filariasis currently relies on mass treatment with four to six annual doses of antifilarial drugs. The goal is to reduce the reservoir of microfilariae in the blood to a level that is insufficient to maintain transmission by the mosquito vector. METHODS In nearly 2500 residents of Papua New Guinea, we prospectively assessed the effects of four annual treatments with a single dose of diethylcarbamazine plus ivermectin or diethylcarbamazine alone on the incidence of microfilariae-positive infections, the severity of lymphatic disease, and the rate of transmission of Wuchereria bancrofti by mosquitoes. Random assignment to treatment regimens was carried out according to the village of residence, and villages were categorized as having moderate or high rates of transmission. RESULTS The four annual treatments with either drug regimen were taken by 77 to 86 percent of the members of the population who were at least five years old; treatments were well tolerated. The proportion with microfilariae-positive infections decreased by 86 to 98 percent, with a greater reduction in areas with a moderate rate of transmission than in those with a high rate. The respective aggregate frequencies of hydrocele and leg lymphedema were 15 percent and 5 percent before the trial began, and 5 percent (P<0.001) and 4 percent (P=0.04) after five years. Hydrocele and leg lymphedema were eliminated in 87 percent and 69 percent, respectively, of those who had these conditions at the outset. The rate of transmission by mosquitoes decreased substantially, and new microfilariae-positive infections in children were almost completely prevented over the five-year study period. CONCLUSIONS Annual mass treatment with drugs such as diethylcarbamazine can virtually eliminate the reservoir of microfilariae and greatly reduce the frequency of clinical lymphatic abnormalities due to bancroftian filariasis. Eradication may be possible in areas with moderate rates of transmission, but longer periods of treatment or additional control measures may be necessary in areas with high rates of transmission.
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Affiliation(s)
- Moses J Bockarie
- Papua New Guinea Institute of Medical Research, Goroka, Madang, Papua New Guinea
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25
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Williams SA, Laney SJ, Bierwert LA, Saunders LJ, Boakye DA, Fischer P, Goodman D, Helmy H, Hoti SL, Vasuki V, Lammie PJ, Plichart C, Ramzy RMR, Ottesen EA. Development and standardization of a rapid, PCR-based method for the detection of Wuchereria bancrofti in mosquitoes, for xenomonitoring the human prevalence of bancroftian filariasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96 Suppl 2:S41-6. [PMID: 12625916 DOI: 10.1179/000349802125002356] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PCR has recently been studied as a promising tool for monitoring the progress of efforts to eliminate lymphatic filariasis. PCR can be used to test concurrently at least 30 pools, with as many as 40 mosquitoes in each pool, for the presence of filarial larvae. The SspI PCR assay for the detection of Wuchereria bancrofti DNA in pools of mosquitoes has been used since 1994 in a variety of laboratories worldwide. During that time, the original assay has been modified in these different laboratories and no standardized assay currently exists. In an effort to standardize and improve the assay, a meeting was held on 15-16 November 2001, at Emory University in Atlanta, with representatives from most of the laboratories currently using the assay. The first round of testing was designed to test the four most promising methods for DNA extraction from pools of mosquitoes. Two of the four methods stood out as clearly the best and these will be now optimised and evaluated in two further rounds of testing.
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Affiliation(s)
- S A Williams
- Clark Science Center, Smith College, Northampton, MA 01063, USA.
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Das PK, Ramaiah KD. Entomological monitoring of annual mass drug administrations for the control or elimination of lymphatic filariasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2002; 96 Suppl 2:S139-42. [PMID: 12625926 DOI: 10.1179/000349802125002491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Together, the interruption of transmission, through annual mass treatments with antifilarial drugs, and the alleviation of suffering in chronic cases form the principal strategy of the Global Programme to Eliminate Lymphatic Filariasis (GPELF). Entomological monitoring of the annual mass drug administrations is necessary to assess transmission levels and progress towards control or elimination of lymphatic filariasis. However, the traditional procedures for entomological monitoring, such as the dissection of mosquitoes caught manually, either as they come to bite at night or as they rest by day, are cumbersome, cost-prohibitive and often not feasible in large-scale control programmes. The collection of mosquitoes in traps and the assessment of their infection status using PCR-based assays offer promise and need to be established as a routine part of control programmes. It is proposed that-to verify the interruption of transmission or determine the prevalence of mosquito infection-1% of the villages/communities in each intervention unit be sampled, mosquitoes be collected from at least 100 households in each study village, and 10 female mosquitoes or all of those collected (whichever is the lower number) from each study house then be checked for infection.
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Affiliation(s)
- P K Das
- Vector Control Research Centre (Indian Council of Medical Research), Medical Complex, Indira Nagar, Pondicherry - 605 006, India.
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Ramzy RMR. Recent advances in molecular diagnostic techniques for human lymphatic filariasis and their use in epidemiological research. Trans R Soc Trop Med Hyg 2002; 96 Suppl 1:S225-9. [PMID: 12055843 DOI: 10.1016/s0035-9203(02)90080-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Diagnosis of lymphatic filariasis for epidemiological studies is an area of science that has been greatly modernized over the last two decades. Recent developments and the introduction of new technologies have led to the replacement of traditional diagnostic methods that were insensitive, tedious and often impractical with molecular biology techniques that have considerable potential for field use. This paper reviews some of these major new techniques and the applications of molecular diagnosis in the field of lymphatic filariasis.
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Affiliation(s)
- Reda M R Ramzy
- Research and Training Centre for Research on Vectors of Disease, Ain Shams University, Abbassia, Cairo, Egypt
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Kamal IH, Fischer P, Adly M, El Sayed AS, Morsy ZS, Ramzy RMR. Evaluation of a PCR-ELISA to detect Wuchereria bancroftiin Culex pipiensfrom an Egyptian village with a low prevalence of filariasis. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2001. [DOI: 10.1080/00034983.2001.11813703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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