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Attaway C, Mathison BA, Misra A. No longer stuck in the past: new advances in artificial intelligence and molecular assays for parasitology screening and diagnosis. Curr Opin Infect Dis 2024; 37:357-366. [PMID: 39133581 DOI: 10.1097/qco.0000000000001041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
PURPOSE OF REVIEW Emerging technologies are revolutionizing parasitology diagnostics and challenging traditional methods reliant on microscopic analysis or serological confirmation, which are known for their limitations in sensitivity and specificity. This article sheds light on the transformative potential of artificial intelligence and molecular assays in the field, promising more accurate and efficient detection methods. RECENT FINDINGS Artificial intelligence has emerged as a promising tool for blood and stool parasite review, when paired with comprehensive databases and expert oversight result in heightened specificity and sensitivity of diagnoses while also increasing efficiency. Significant strides have been made in nucleic acid testing for multiplex panels for enteric pathogen. Both multiplex and single target panels for Plasmodium , Babesia , filaria, and kinetoplastids have been developed and garnered regulatory approval, notably for blood donor screening in the United States. Additional technologies such as MALDI-TOF, metagenomics, flow cytometry, and CRISPR-Cas are under investigation for their diagnostic utility and are currently in the preliminary stages of research and feasibility assessment. SUMMARY Recent implementation of artificial intelligence and digital microscopy has enabled swift smear screening and diagnosis, although widespread implementation remains limited. Simultaneously, molecular assays - both targeted and multiplex panels are promising and have demonstrated promise in numerous studies with some assays securing regulatory approval recently. Additional technologies are under investigation for their diagnostic utility and are compelling avenues for future proof-of-concept diagnostics.
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Affiliation(s)
| | - Blaine A Mathison
- Scientist III, Institute for Clinical and Experimental Pathology, ARUP Laboratories, Department of Pathology, University of Utah, Salt Lake City, Utah, USA
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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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Ramesh A, Oliveira P, Cameron M, Castanha PMS, Walker T, Lenhart A, Impoinvil L, Alexander N, Medeiros Z, Sá A, Rocha A, Souza WV, Maciel A, Braga C. Postintervention Immunological and Entomological Survey of Lymphatic Filariasis in the City of Olinda, Brazil, 2015-2016. Am J Trop Med Hyg 2024; 110:470-482. [PMID: 38350158 PMCID: PMC10919178 DOI: 10.4269/ajtmh.23-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 11/05/2023] [Indexed: 02/15/2024] Open
Abstract
Lymphatic filariasis (LF) is a leading cause of disability due to infectious disease worldwide. The Recife Metropolitan Region (RMR) is the only remaining focus of LF in Brazil, where the parasite Wuchereria bancrofti is transmitted solely by the mosquito Culex quinquefasciatus. This study reports the results of transmission assessment surveys and molecular xenomonitoring in the city of Olinda, RMR, after nearly 15 years (2015-2016) of interventions for LF elimination. Participants were screened for W. bancrofti antigen via immunochromatographic card tests (ICT) in: 1) door-to-door surveys conducted for all children aged 5-7 years from 4 out of 17 intervention areas treated with at least five annual doses of mass drug administration (MDA), and 2) a two-stage cluster sampling survey of residents aged 5 years and older in non-MDA areas. Mosquitoes were collected via handheld aspirators in four MDA areas, differentiated by species, sex, and physiological status, pooled into groups of up to 10 blood-fed, semigravid, and gravid mosquitoes, and screened for W. bancrofti infection by real-time quantitative polymerase chain reaction (RT-qPCR). All 1,170 children from MDA areas and the entire population sample of 990 residents in non-MDA areas were ICT negative. In MDA areas, a total of 3,152 female Cx. quinquefasciatus mosquitoes in 277 households (range, 0-296 mosquitoes per house) were collected via aspiration. RT-qPCR of 233 pools of mosquitos were negative for W. bancrofti RNA; an independent reference laboratory confirmed these results. These results provide evidence that LF transmission has been halted in this setting.
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Affiliation(s)
- Anita Ramesh
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Paula Oliveira
- National Reference Service for Lymphatic Filariasis, Department of Parasitology, Instituto Aggeu Magalhães/FIOCRUZ, Recife, Brazil
| | - Mary Cameron
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Priscila M. S. Castanha
- Faculty of Medical Science, University of Pernambuco, Recife, Brazil
- School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Thomas Walker
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, United Kingdom
- School of Life Sciences, The University of Warwick, Coventry, United Kingdom
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Lucy Impoinvil
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Neal Alexander
- Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Zulma Medeiros
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
| | - André Sá
- Collective Health Department, Instituto Aggeu Magalhães/FIOCRUZ
| | - Abraham Rocha
- National Reference Service for Lymphatic Filariasis, Department of Parasitology, Instituto Aggeu Magalhães/FIOCRUZ, Recife, Brazil
| | - Wayner V. Souza
- Collective Health Department, Instituto Aggeu Magalhães/FIOCRUZ
| | - Amélia Maciel
- Department of Tropical Medicine, Federal University of Pernambuco, Recife, Brazil
| | - Cynthia Braga
- Department of Parasitology, Instituto Aggeu Magalhães/Fundação Oswaldo Cruz (FIOCRUZ), Recife, Brazil
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Oyeyemi OT, Ogundahunsi O, Schunk M, Fatem RG, Shollenberger LM. Neglected tropical disease (NTD) diagnostics: current development and operations to advance control. Pathog Glob Health 2024; 118:1-24. [PMID: 37872790 PMCID: PMC10769148 DOI: 10.1080/20477724.2023.2272095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023] Open
Abstract
Neglected tropical diseases (NTDs) have become important public health threats that require multi-faceted control interventions. As late treatment and management of NTDs contribute significantly to the associated burdens, early diagnosis becomes an important component for surveillance and planning effective interventions. This review identifies common NTDs and highlights the progress in the development of diagnostics for these NTDs. Leveraging existing technologies to improve NTD diagnosis and improving current operational approaches for deployment of developed diagnostics are crucial to achieving the 2030 NTD elimination target. Point-of-care NTD (POC-NTD) diagnostic tools are recommended preferred diagnostic options in resource-constrained areas for mapping risk zones and monitoring treatment efficacy. However, few are currently available commercially. Technical training of remote health care workers on the use of POC-NTD diagnostics, and training of health workers on the psychosocial consequences of these diagnostics are critical in harnessing POC-NTD diagnostic potential. While the COVID-19 pandemic has challenged the possibility of achieving NTD elimination in 2030 due to the disruption of healthcare services and dwindling financial support for NTDs, the possible contribution of NTDs in exacerbating COVID-19 pandemic should motivate NTD health system strengthening.
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Affiliation(s)
- Oyetunde T. Oyeyemi
- Department of Biosciences and Biotechnology, University of Medical Sciences, Ondo, Nigeria
- Department of Biological Sciences, Old Dominion University, Virginia, USA
| | - Olumide Ogundahunsi
- The Central Office for Research and Development (CORD), University of Medical Sciences, Ondo, Nigeria
| | - Mirjam Schunk
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU) institution, Munich, Germany
| | - Ramzy G. Fatem
- Schistosome Biological Supply Center, Theodor Bilharz Research Institute, Giza, Egypt
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Amambo GN, Innocentia N, Abong RA, Fombad FF, Njouendou AJ, Nietcho F, Ekanya R, Kien CA, Ebai R, Lenz B, Ritter M, Esum ME, Deribe K, Cho JF, Beng AA, Enyong PI, Li Z, Hübner MP, Pfarr K, Hoerauf A, Carlow C, Wanji S. Application of loop mediated isothermal amplification (LAMP) assays for the detection of Onchocerca volvulus, Loa loa and Mansonella perstans in humans and vectors. FRONTIERS IN TROPICAL DISEASES 2023; 3:1016176. [PMID: 36684508 PMCID: PMC7614089 DOI: 10.3389/fitd.2022.1016176] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Conventional diagnosis of filarial infections is based on morphological identification of microfilariae using light microscopy and requires considerable expertise, is time-consuming, and can be subjective. Loop-mediated isothermal amplification (LAMP) has advantages over microscopy or PCR because of its operational simplicity, rapidity and versatility of readout options. LAMP assays represent a major step forward in improved filarial diagnostic tools suitable for low resource settings and field applicability. The study goal was to retrospectively evaluate the performance and suitability of the O-150, RF4, and Mp419 LAMP assays for diagnosing Onchocerca volvulus, Loa loa and Mansonella perstans infections, respectively, in humans and vectors under experimental and natural field conditions. Surveys were conducted in four health districts of Cameroon using skin snip and thick blood film methods to detect skin (O. volvulus) and blood (L. loa and M. perstans) dwelling microfilaria in humans. Engorged vectors (Simulium spp., Chrysops spp., and Culicoides spp.) were evaluated by LAMP. Dissected, wild-caught vectors were also analyzed. LAMP showed a prevalence of 40.4% (O. volvulus), 17.8% (L. loa) and 36.6% (M. perstans) versus 20.6% (O. volvulus), 17.4% (L. loa) and 33.8% (M. perstans) with microscopy. Simulium spp. were dissected for microscopy and pooled for LAMP. The O-150 LAMP assay infection rate was 4.3% versus 4.1% by microscopy. Chrysops spp. were dissected and analyzed individually in the LAMP assay. The RF4 LAMP assay infection rate was 23.5% versus 3.3% with microscopy. The RF4 LAMP assay also detected parasites in Chrysops spp. fed on low microfilaremic volunteers. The Mp419 LAMP assay infection rate was 0.2% for C. milnei and 0.04% for C. grahamii, while three other species were LAMP-negative. The sensitivity, species specificity, rapidity and ease of its use of these filarial LAMP assays, and validation of their performance in the field support use as alternatives to microscopy as diagnostic and surveillance tools in global health programs aimed to eliminate onchocerciasis.
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Affiliation(s)
- Glory Ngongeh Amambo
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Ngong Innocentia
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Raphael Awah Abong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Fanny Fri Fombad
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Abdel Jelil Njouendou
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Department of Biomedical Science, Faculty of Health Sciences, University of Buea, Buea, Cameroon
| | - Franck Nietcho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
| | - Relindis Ekanya
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Chi Anizette Kien
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Rene Ebai
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Benjamin Lenz
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Manuel Ritter
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
| | - Mathias Eyong Esum
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, United Kingdom
- School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia
| | - Jerome Fru Cho
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Amuam Andrew Beng
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Peter Ivo Enyong
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
| | - Zhiru Li
- New England Biolabs, Ipswich, MA, United States
| | - Marc P. Hübner
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Kenneth Pfarr
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
| | - Achim Hoerauf
- Institute of Medical Microbiology, Immunology and Parasitology, University Hospital Bonn, Bonn, Germany
- German Center for Infection Research (DZIF), Partner Site Bonn-Cologne, Bonn, Germany
- German-West African Centre for Global Health and Pandemic Prevention (G-WAC), Partner Site Bonn, Bonn, Germany
| | | | - Samuel Wanji
- Parasites and Vector Research Unit (PAVRU), Department of Microbiology and Parasitology, University of Buea, Buea, Cameroon
- Research Foundation in Tropical Diseases and Environment (REFOTDE), Buea, Cameroon
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de Souza DK, Otchere J, Sumboh JG, Asiedu O, Opare J, Asemanyi-Mensah K, Boakye DA, Gass KM, Long EF, Ahorlu CS. Finding and eliminating the reservoirs: Engage and treat, and test and treat strategies for lymphatic filariasis programs to overcome endgame challenges. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.953094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many lymphatic filariasis (LF) endemic countries, including Ghana, have successfully implemented mass drug administration (MDA) and made significant progress towards the elimination of the disease as a public health problem. Unfortunately, the existence of individuals who seldom or never take part in MDA pose a threat to this success, as they may serve as reservoirs of infection, re-infecting their communities. In this study we implemented strategies to identify and treat these individuals, while also assessing their level of infection, to inform programme actions. The study was undertaken in the Ahanta West hotspot district in Ghana, which has received more than 17 rounds of MDA. Through the community registers used in recording participation in MDAs, we identified and offered treatment to individuals who were ineligible or inadvertently missed the last MDA in April 2021 (Engage and Treat – E&T), or testing using the filariasis test strip followed by treatment to community members who for various reasons chose not to participate in the last MDA (Test and Treat – T&T). During the study, 23,879 individuals ranging from 5 to 98 years were reached, of whom 78% were not captured in the MDA register. Among the E&T group, 75.06% willingly received and swallowed the treatment drugs. The remaining 24.94% were offered testing followed by a re-engagement to receive the drug in the T&T group. Overall, 22,830 (95.61%) of participants were treated by either strategy. Of the participants in the T&T group, 516 (8.66%; 95% CI= 7.96 – 9.41) were positive by the FTS. The highest antigen prevalence was detected among children 5 to 10 years, with 16.59% (95% CI= 12.02 – 22.06) and 22.54% (95% CI= 17.11 – 28.74) among females and males, respectively. Mapping of the data revealed that most infections are in a few select communities. Of the 516 FTS positives, 27.33% reportedly missed MDA once, 18.41% missed MDA twice and 54.26% missed all of the last three MDAs. The main reasons for missing MDA included absence (25.49%), travel (21.24%), being unaware of MDA (20.27%), refusals to take the drug (10.65%), illnesses (7.07%) and fear of adverse events (6.13%). This study demonstrates that greater sensitization and engagement strategies, with a test and treat strategy reserved for the most hesitant individuals, could significantly increase the number of individuals who receive treatment and therefore help districts reach their elimination targets by reducing the remaining reservoir or infection. NTD programmes require new tools to help them identify, engage and treat these individuals, as part of their overall monitoring and evaluation strategy.
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Senkwe MN, Berta KK, Logora SMY, Sube J, Bidali A, Abe A, Onyeze A, Pita J, Rumunu J, Maleghemi S, Ndenzako F, Olu OO. Prevalence and factors associated with transmission of lymphatic filariasis in South Sudan: a cross-sectional quantitative study. Pan Afr Med J 2022; 42:9. [PMID: 36158938 PMCID: PMC9474850 DOI: 10.11604/pamj.supp.2022.42.1.33895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 05/30/2022] [Indexed: 11/30/2022] Open
Abstract
Introduction South Sudan is affected by a high burden of Neglected Tropical Diseases (NTDs). The country is very vulnerable to NTDs due to its favourable tropical climate and multiple risk factors. However, the distribution of the diseases and the populations at risk for the various NTDs is unknown. This paper describes the distribution of lymphatic filariasis (LF) in 58 counties of South Sudan. Methods a descriptive quantitative cross-sectional study of LF in 58 counties in 8 states of South Sudan recruited adult volunteers aged ≥ 15 years tested for circulating filarial antigens (CFA). A quantitative descriptive statistical was performed to determine the prevalence rates and the endemicity (CFA positivity rate ≥1%) of lymphatic filariasis in 9213 adult individuals from 101 villages. Results the overall prevalence of positive CFA was 1.6%, and the highest state prevalence was reported in the Upper Nile state at 3.4%. Based on the prevalence of positive CFA 64% of the surveyed counties are endemic to lymphatic filariasis. The endemicity ranged from 1-11.1% positive CFA. The highest prevalence of positive CAF was observed in the >50 years old age group (2.7%), followed by the 46-50 age group (2.3%). Males tested more positive than females (52.4% Vs 47.6%). Participants were three times more likely to test positive for CFA on filarial test strips (FTS) compared to immunochromatographic test (ICT). There was a statistically significant difference in the prevalence of positive CFA among the two tests (P=.002). Conclusion the distribution of LF is widespread, with varying transmission risks. The produced prevalence maps of infection provided evidence on the areas for targeted interventions in the national NTD program in South Sudan. An increased number of positive CFA were identified using FTS than ICT; hence, it is advisable to use FTS in the future transmission survey.
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Affiliation(s)
| | | | | | - Julia Sube
- World Health Organization, WHO Country Office, Juba, South Sudan
| | - Alex Bidali
- World Health Organization, WHO Country Office, Juba, South Sudan
| | - Abias Abe
- National Public Health Laboratory, Juba, South Sudan
| | - Adiele Onyeze
- Multicountry Assignment Team Support Team, World Health Organization, Nairobi, Kenya
| | - Jane Pita
- World Health Organization, WHO Country Office, Juba, South Sudan
| | | | | | - Fabian Ndenzako
- World Health Organization, WHO Country Office, Juba, South Sudan
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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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Sheel M, Lau CL, Sheridan S, Fuimaono S, Graves PM. Comparison of Immunochromatographic Test (ICT) and Filariasis Test Strip (FTS) for Detecting Lymphatic Filariasis Antigen in American Samoa, 2016. Trop Med Infect Dis 2021; 6:tropicalmed6030132. [PMID: 34287387 PMCID: PMC8293346 DOI: 10.3390/tropicalmed6030132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 11/16/2022] Open
Abstract
Circulating filarial antigen (Ag) prevalence, measured using rapid point-of-care tests, is the standard indicator used for monitoring and surveillance in the Global Program to Eliminate Lymphatic Filariasis. In 2015, the immunochromatographic test (ICT) was replaced with the filariasis test strip (FTS), which has higher reported sensitivity. Despite differences in sensitivity, no changes in recommended surveillance targets were made when the FTS was introduced. In 2016, we conducted lymphatic filariasis surveys in American Samoa using FTS, which found higher Ag prevalence than previous surveys that used ICT. To determine whether the increase was real, we assessed the concordance between FTS and ICT results by paired testing of heparinised blood from 179 individuals (63% FTS-positive). ICT had 93.8% sensitivity and 100% specificity for identifying FTS-positive persons, and sensitivity was not associated with age, gender, or presence of microfilariae. Based on these findings, if ICT had been used in the 2016 surveys, the results and interpretation would have been similar to those reported using FTS. American Samoa would have failed Transmission Assessment Survey (TAS) of Grade 1 and 2 children with either test, and community prevalence would not have been significantly different (4.1%, 95% CI, 3.3-4.9% with FTS vs. predicted 3.8%, 95%, CI: 3.1-4.6% with ICT).
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Affiliation(s)
- Meru Sheel
- National Centre for Epidemiology and Health, Research School of Population Health, ANU College of Health and Medicine, The Australian National University, Acton 2601, Australia
- Correspondence:
| | - Colleen L. Lau
- Faculty of Medicine, School of Public Health, University of Queensland, Brisbane 4006, Australia;
- Research School of Population Health, ANU College of Health and Medicine, The Australian National University, Acton 2601, Australia
| | - Sarah Sheridan
- National Centre for Immunisation Research and Surveillance, Westmead 2145, Australia;
| | | | - Patricia M. Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns 4870, Australia;
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Kamgno J, Djeunga HN. Progress towards global elimination of lymphatic filariasis. LANCET GLOBAL HEALTH 2020; 8:e1108-e1109. [PMID: 32827473 DOI: 10.1016/s2214-109x(20)30323-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 11/19/2022]
Affiliation(s)
- Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon; Department of Public Health, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon.
| | - Hugues Nana Djeunga
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon; Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
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11
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Minetti C, Pilotte N, Zulch M, Canelas T, Tettevi EJ, Veriegh FBD, Osei-Atweneboana MY, Williams SA, Reimer LJ. Field evaluation of DNA detection of human filarial and malaria parasites using mosquito excreta/feces. PLoS Negl Trop Dis 2020; 14:e0008175. [PMID: 32267840 PMCID: PMC7170280 DOI: 10.1371/journal.pntd.0008175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/20/2020] [Accepted: 02/27/2020] [Indexed: 12/02/2022] Open
Abstract
We recently developed a superhydrophobic cone-based method for the collection of mosquito excreta/feces (E/F) for the molecular xenomonitoring of vector-borne parasites showing higher throughput compared to the traditional approach. To test its field applicability, we used this platform to detect the presence of filarial and malaria parasites in two villages of Ghana and compared results to those for detection in mosquito carcasses and human blood. We compared the molecular detection of three parasites (Wuchereria bancrofti, Plasmodium falciparum and Mansonella perstans) in mosquito E/F, mosquito carcasses and human blood collected from the same households in two villages in the Savannah Region of the country. We successfully detected the parasite DNA in mosquito E/F from indoor resting mosquitoes, including W. bancrofti which had a very low community prevalence (2.5-3.8%). Detection in the E/F samples was concordant with detection in insect whole carcasses and human blood, and a parasite not vectored by mosquitoes was detected as well.Our approach to collect and test mosquito E/F successfully detected a variety of parasites at varying prevalence in the human population under field conditions, including a pathogen (M. perstans) which is not transmitted by mosquitoes. The method shows promise for further development and applicability for the early detection and surveillance of a variety of pathogens carried in human blood.
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Affiliation(s)
- Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Nils Pilotte
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Michael Zulch
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
| | - Tiago Canelas
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Edward J. Tettevi
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research, Accra, Ghana
| | - Francis B. D. Veriegh
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research, Accra, Ghana
| | - Mike Yaw Osei-Atweneboana
- Biomedical and Public Health Research Unit, CSIR-Water Research Institute, Council for Scientific and Industrial Research, Accra, Ghana
| | - Steven A. Williams
- Department of Biological Sciences, Smith College, Northampton, Massachusetts, United States of America
- Molecular and Cellular Biology Program, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Lisa J. Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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12
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Yasin N, Sugerappa Laxmanappa H, Muddapur UM, Cheruvathur J, Uday Prakash SM, Venkataramaiah Thulasiram H. Design, expression, and evaluation of novel multiepitope chimeric antigen of Wuchereria bancrofti for the diagnosis of lymphatic filariasis - A structure-based strategy. Int Immunopharmacol 2020; 83:106431. [PMID: 32222640 DOI: 10.1016/j.intimp.2020.106431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/04/2020] [Accepted: 03/19/2020] [Indexed: 11/25/2022]
Abstract
The Global Program for Elimination Lymphatic Filariasis (GPELF) is in an advanced stage and requires tools for diagnosing infection, assessing transmission and certification. This study was aimed at developing an antibody-based assay using a chiemric antigen containing multi-B-cell epitopes from antigens highly expressed in different stages of Wuchereria bancrofti to detect LF infection and its transmission. The antigen was express cloned and two indirect ELISA based (IgG1 & IgG4 based) antibody assays were developed using the recombinant antigen. The chimeric antigen displayed 1 and 3-fold reactivity with IgG1 and IgG4 antibodies, respectively in microfilaraial (mf) positive sera when compared to that in sera samples of Non-endemic normal sera (NEN) (O.D, 0.13 ± 0.20 and 0.18 ± 0.07), thus differentiating infected from uninfected individuals. In IgG1 and IgG4 antibody assays, the multiepitope antigen also showed reactivity (O.D, 0.27 ± 0.18 and 0.16 ± 0.03) in a small proportion (18 and 30, respectively out of 156) endemic normal individuals and in IgG1 antibody in a few (4) chronic patients (CP). The antigen did not react with IgG1 or IgG4 antibodies in the sera samples of malaria, scrub typhus, dengue, hookworm, and roundworm helminth cases (0.139 ± 0.018, 0.144 ± 0.007 0.17804 ± 0.007 and 0.162 ± 0.006), thus showing its high specificity. The sensitivity (%) and specificity (%) of the multi-epitope antigen-based IgG1 and IgG4 antibody assays are 100, 98.1 and 100, 99.52, respectively. Thus, the recombinant multiepitope antigen appears to have good potential in detecting active LF infection and in assessing its transmission in endemic communities.
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Affiliation(s)
- Nazeer Yasin
- Indian Council of Medical Research-National Institute of Traditional Medicine, Belagavi 590010, Karnataka, India
| | - Hoti Sugerappa Laxmanappa
- Indian Council of Medical Research-National Institute of Traditional Medicine, Belagavi 590010, Karnataka, India.
| | - Uday M Muddapur
- Department of Biotechnology, B.V.B College of Engineering and Technology, Hubballi 580031, Karnataka, India
| | - Jennifer Cheruvathur
- CSIR-National Chemical Laboratory, Organic Chemistry Division, Pune 411008, Maharashtra, India
| | - S M Uday Prakash
- Molecular Genetics Laboratory, School of Biotechnology, National Institute of Technology Calicut, Calicut 673601, Kerala, India
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13
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Xavier A, Oliveira H, Aguiar-Santos A, Barbosa Júnior W, da Silva E, Braga C, Bonfim C, Medeiros Z. Assessment of transmission in areas of uncertain endemicity for lymphatic filariasis in Brazil. PLoS Negl Trop Dis 2019; 13:e0007836. [PMID: 31765388 PMCID: PMC6917295 DOI: 10.1371/journal.pntd.0007836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 12/17/2019] [Accepted: 10/09/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The objective of the Global Program to Eliminate Lymphatic Filariasis (GPELF) is to phase out this endemic disease as a public health problem by 2020. Validation of elimination is obtained from the World Health Organization through evidence of non-transmission in countries that have already been subjected to mass drug administration (MDA) and in places adjoining these endemic areas. While three municipalities in Brazil have completed MDA, the epidemiological situation remains uncertain in nine adjoining municipalities. To determine the epidemiological status, this study was to perform a review of the literature and a school-based survey to describe the past and recent endemicity of lymphatic filariasis (LF) theses nine municipalities in Brazil. METHODOLOGY/PRINCIPLE FINDINGS For review of the literature, both formal and informal literature sources were accessed since the first reports of filariasis in the Metropolitan Region of Recife, Brazil. We conducted a school-based survey in 2016 using immunochromatographic card tests (ICTs) among schoolchildren aged 6-10 years living in nine municipalities contiguous with the endemic areas in which MDA was conducted. Our review of the literature identified eight studies involving surveys demonstrating that microfilariae had been circulating in eight of the municipalities since 1967, with a low prevalence of microfilaremia, isolated autochthonous cases, and treatment of individual cases. The school-based survey included 17,222 children in 185 urban schools in the nine areas of Brazil with uncertain endemicity. One child affected by allochthonous transmission was antigen positive based on ICT and lived in a municipality adjacent to Recife; this child's family came from Recife, but no other case was diagnosed within the family. CONCLUSIONS/SIGNIFICANCE The study results suggest that there is no transmission of LF in the municipalities investigated. However, these areas have population migration and socioenvironmental conditions favorable to mosquito breeding grounds; therefore, surveillance is strongly recommended in these areas.
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Affiliation(s)
- Amanda Xavier
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Pernambuco, Recife, Brazil
- * E-mail:
| | - Heloize Oliveira
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Pernambuco, Recife, Brazil
- Agência Pernambucana de Vigilância Sanitária, Secretaria de Saúde do Estado de Pernambuco, Recife, Brazil
| | - Ana Aguiar-Santos
- Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Brazil
| | - Walter Barbosa Júnior
- Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Brazil
| | - Ellyda da Silva
- Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Brazil
| | - Cynthia Braga
- Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Brazil
| | - Cristine Bonfim
- Diretoria de Pesquisas Sociais, Fundação Joaquim Nabuco, Ministério da Educação, Recife, Brazil
- Programa de Pós-graduação em Saúde Coletiva, Universidade Federal de Pernambuco, Recife, Brazil
| | - Zulma Medeiros
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Pernambuco, Recife, Brazil
- Departamento de Parasitologia, Instituto Aggeu Magalhães, Fundação Oswaldo Cruz, Recife, Brazil
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14
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Silva E, Xavier A, Silva E, Barbosa Júnior W, Rocha A, Freitas V, Oliveira P, Aguiar-Santos AM, Bonfim C, Medeiros Z. Evaluation of lymphatic filariasis in endemic area of Brazil where mass drug administration is not required. Pathog Glob Health 2019; 113:143-148. [PMID: 31138026 DOI: 10.1080/20477724.2019.1623546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Mass drug administration (MDA) is the main counter-transmission strategy of the Global Programme to Eliminate Lymphatic Filariasis. In endemic countries, there are areas where MDA is not required. However, there is no standard approach in these areas, and studies are important to evaluate the epidemiological status. This study aimed to investigate lymphatic filariasis and strategies developed for its control in an area where MDA is not required. Together with the 2018 morbidity evaluation, a survey was conducted using point-of-care immunochromatographic test-AD12 tests for diagnostic screening in an area where MDA is not required. The methodology also included desk research based on Health Department reports of the control activities for lymphatic filariasis during 2003-2016. Among the 934 cases investigated in 2018, there was a 0.64% prevalence of circulating filarial antigen positive, comprising five adults and one 2-year-old child. Six patients aged 39-63 years had filarial disease. Fourteen surveys have already been conducted as control activities, and since 2009, there have been no positive cases. This study showed that the prevalence of antigenemia decreased from 2.97% in 2003 to 0.64% in 2018. Moreover, the transmission of filariasis infection was under control in this area. Our study provides insights into the surveillance phase by identifying areas of low transmission and where MDA is not required. Although we have not identified cases of filarial infection, there is a need to provide services that will provide assist those already affected with morbidity and help reduce and prevent disability.
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Affiliation(s)
- Ellyda Silva
- a Programa de Pós-graduação em Biociências e Biotecnologia em Saúde , Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
| | - Amanda Xavier
- b Programa de Pós-graduação em Ciências da Saúde , Universidade de Pernambuco (UPE) , Recife , Pernambuco , Brasil
| | - Elis Silva
- a Programa de Pós-graduação em Biociências e Biotecnologia em Saúde , Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
| | - Walter Barbosa Júnior
- a Programa de Pós-graduação em Biociências e Biotecnologia em Saúde , Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
| | - Abraham Rocha
- c Serviço de Referencia Nacional em Filarioses, Departamento de Parasitologia , Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil.,d Secretaria de Saúde do Estado de Pernambuco , Laboratório do Hospital Otávio de Freitas , Recife , Pernambuco , Brazil
| | - Vania Freitas
- e Secretária Municipal de Saúde de Jaboatão dos Guararapes , Diretoria de Vigilância em Saúde , Jaboatão dos Guararapes , Pernambuco , Brazil
| | - Paula Oliveira
- c Serviço de Referencia Nacional em Filarioses, Departamento de Parasitologia , Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
| | - Ana Maria Aguiar-Santos
- c Serviço de Referencia Nacional em Filarioses, Departamento de Parasitologia , Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
| | - Cristine Bonfim
- f Diretoria de Pesquisas Sociais, Núcleo de Estudos em Estatísticas Sociais , Fundação Joaquim Nabuco (FUNDAJ) , Recife , Pernambuco , Brasil.,g Programa de Pós-graduação em Saúde Coletiva , Universidade Federal de Pernambuco (UFPE) , Recife , Pernambuco , Brasil
| | - Zulma Medeiros
- a Programa de Pós-graduação em Biociências e Biotecnologia em Saúde , Instituto Aggeu Magalhães (IAM), Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil.,b Programa de Pós-graduação em Ciências da Saúde , Universidade de Pernambuco (UPE) , Recife , Pernambuco , Brasil.,c Serviço de Referencia Nacional em Filarioses, Departamento de Parasitologia , Instituto Aggeu Magalhães, Fundação Oswaldo Cruz (FIOCRUZ) , Recife , Pernambuco , Brasil
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15
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Nchoutpouen E, Talipouo A, Djiappi-Tchamen B, Djamouko-Djonkam L, Kopya E, Ngadjeu CS, Doumbe-Belisse P, Awono-Ambene P, Kekeunou S, Wondji CS, Antonio-Nkondjio C. Culex species diversity, susceptibility to insecticides and role as potential vector of Lymphatic filariasis in the city of Yaoundé, Cameroon. PLoS Negl Trop Dis 2019; 13:e0007229. [PMID: 30943198 PMCID: PMC6464241 DOI: 10.1371/journal.pntd.0007229] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 04/15/2019] [Accepted: 02/10/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Culex species are widespread across Cameroon and responsible for high burden of nuisance in most urban settings. However, despite their high nuisance, they remain less studied compared to anophelines. The present study aimed to assess Culex species distribution, susceptibility to insecticide, bionomics and role in Lymphatic Filariasis (LF) transmission in the city of Yaoundé. METHODS Mosquito collections were conducted from March to December 2017 using Centre for Disease Control light traps (CDC-LT), human landing catches (HLC) and larval collections. Mosquitoes were identified using morphological identification keys. Mosquitoes from the Culex pipiens complex were further identified using Polymerase Chain Reaction (PCR) to assess the presence of sibling species. Bioassays were conducted with 2-5 day-old unfed females to assess mosquito susceptibility to DDT, permethrin, deltamethrin and bendiocarb following WHO guidelines. Dead, control and surviving mosquitoes from bioassays were screened by PCR to detect the presence of knockdown resistance (kdr) alleles. Pools of mosquitoes were examined by PCR to detect the presence of Wuchereria bancrofti. RESULTS A total of 197,956 mosquitoes belonging to thirteen species were collected. The density of mosquito collected varied according to the collection methods, districts and seasons. Culex quinquefasciatus emerged as the most abundant and the only species of the Culex pipiens complex in Yaoundé. Culex species were found breeding in different types of breeding sites including polluted and unpolluted sites. All Culex species including Cx antennatus, Cx duttoni, Cx perfuscus and Cx tigripes were found to be highly resistant to permethrin, deltamethrin and DDT. Culex quinquefasciatus was also found to be resistant to bendiocarb. A high frequency of the West Africa kdr allele was recorded in resistant Cx. quinquefasciatus. Out of the 247 pooled samples of 25 Culex spp. examined for the presence of Wuchereria bancrofti, none was found infected. CONCLUSION The study confirms the high adaptation of Culex species particularly Culex quinquefasciatus to the urban environment and no implication of this species in the transmission of LF in Yaoundé Cameroon. Culex species predominance in urban settings highlight potential transmission risk of West Nile and rift valley fever in Yaoundé.
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Affiliation(s)
- Elysee Nchoutpouen
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Abdou Talipouo
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Borel Djiappi-Tchamen
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Borne Infectious Disease Unit of the Laboratory of Applied Biology and Ecology (VBID-LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Landre Djamouko-Djonkam
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Borne Infectious Disease Unit of the Laboratory of Applied Biology and Ecology (VBID-LABEA), Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Edmond Kopya
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Carmene Sandra Ngadjeu
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Patricia Doumbe-Belisse
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Parfait Awono-Ambene
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
| | | | - Charles Sinclair Wondji
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, United Kingdom
| | - Christophe Antonio-Nkondjio
- Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte Contreles Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Vector Biology Liverpool School of Tropical medicine Pembroke Place, Liverpool, United Kingdom
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Abstract
Lymphatic filariasis (LF) is a parasitic infection that is spread by mosquitos infected with worm larvae. Several factors will affect the global prevalence of LF in the future. A growing body of evidence suggests that climate change will influence the spread of parasitic diseases and their vectors. Lymphatic filariasis is the leading cause of permanent disfigurement and the second most common cause of long-term disability in the world.
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Affiliation(s)
- Gayle B Lourens
- Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA.
| | - Denise K Ferrell
- Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA
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17
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Cook DAN, Pilotte N, Minetti C, Williams SA, Reimer LJ. A superhydrophobic cone to facilitate the xenomonitoring of filarial parasites, malaria, and trypanosomes using mosquito excreta/feces. Gates Open Res 2018; 1:7. [PMID: 29377042 DOI: 10.12688/gatesopenres.12749.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2018] [Indexed: 11/20/2022] Open
Abstract
Background: Molecular xenomonitoring (MX), the testing of insect vectors for the presence of human pathogens, has the potential to provide a non-invasive and cost-effective method for monitoring the prevalence of disease within a community. Current MX methods require the capture and processing of large numbers of mosquitoes, particularly in areas of low endemicity, increasing the time, cost and labour required. Screening the excreta/feces (E/F) released from mosquitoes, rather than whole carcasses, improves the throughput by removing the need to discriminate vector species since non-vectors release ingested pathogens in E/F. It also enables larger numbers of mosquitoes to be processed per pool. However, this new screening approach requires a method of efficiently collecting E/F. Methods: We developed a cone with a superhydrophobic surface to allow for the efficient collection of E/F. Using mosquitoes exposed to either Plasmodium falciparum, Brugia malayi or Trypanosoma brucei brucei, we tested the performance of the superhydrophobic cone alongside two other collection methods. Results: All collection methods enabled the detection of DNA from the three parasites. Using the superhydrophobic cone to deposit E/F into a small tube provided the highest number of positive samples (16 out of 18) and facilitated detection of parasite DNA in E/F from individual mosquitoes. Further tests showed that following a simple washing step, the cone can be reused multiple times, further improving its cost-effectiveness. Conclusions: Incorporating the superhydrophobic cone into mosquito traps or holding containers could provide a simple and efficient method for collecting E/F. Where this is not possible, swabbing the container or using the washing method facilitates the detection of the three parasites used in this study.
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Affiliation(s)
- Darren A N Cook
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Nils Pilotte
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Steven A Williams
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Lisa J Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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18
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Cook DAN, Pilotte N, Minetti C, Williams SA, Reimer LJ. A superhydrophobic cone to facilitate the xenomonitoring of filarial parasites, malaria, and trypanosomes using mosquito excreta/feces. Gates Open Res 2018; 1:7. [PMID: 29377042 PMCID: PMC5781187 DOI: 10.12688/gatesopenres.12749.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2018] [Indexed: 11/20/2022] Open
Abstract
Background: Molecular xenomonitoring (MX), the testing of insect vectors for the presence of human pathogens, has the potential to provide a non-invasive and cost-effective method for monitoring the prevalence of disease within a community. Current MX methods require the capture and processing of large numbers of mosquitoes, particularly in areas of low endemicity, increasing the time, cost and labour required. Screening the excreta/feces (E/F) released from mosquitoes, rather than whole carcasses, improves the throughput by removing the need to discriminate vector species since non-vectors release ingested pathogens in E/F. It also enables larger numbers of mosquitoes to be processed per pool. However, this new screening approach requires a method of efficiently collecting E/F. Methods: We developed a cone with a superhydrophobic surface to allow for the efficient collection of E/F. Using mosquitoes exposed to either Plasmodium falciparum, Brugia malayi or Trypanosoma brucei brucei, we tested the performance of the superhydrophobic cone alongside two other collection methods. Results: All collection methods enabled the detection of DNA from the three parasites. Using the superhydrophobic cone to deposit E/F into a small tube provided the highest number of positive samples (16 out of 18) and facilitated detection of parasite DNA in E/F from individual mosquitoes. Further tests showed that following a simple washing step, the cone can be reused multiple times, further improving its cost-effectiveness. Conclusions: Incorporating the superhydrophobic cone into mosquito traps or holding containers could provide a simple and efficient method for collecting E/F. Where this is not possible, swabbing the container or using the washing method facilitates the detection of the three parasites used in this study.
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Affiliation(s)
- Darren A N Cook
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Nils Pilotte
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Corrado Minetti
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Steven A Williams
- Department of Biological Sciences, Smith College, Northampton, MA, 01063, USA.,Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA, 01003, USA
| | - Lisa J Reimer
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
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Nana-Djeunga HC, Tchouakui M, Njitchouang GR, Tchatchueng-Mbougua JB, Nwane P, Domche A, Bopda J, Mbickmen-Tchana S, Akame J, Tarini A, Epée E, Biholong BD, Zhang Y, Tougoue JJ, Kabore A, Njiokou F, Kamgno J. First evidence of lymphatic filariasis transmission interruption in Cameroon: Progress towards elimination. PLoS Negl Trop Dis 2017; 11:e0005633. [PMID: 28662054 PMCID: PMC5490934 DOI: 10.1371/journal.pntd.0005633] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 05/10/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Lymphatic filariasis (LF) is among the 10 neglected tropical diseases targeted for control or elimination by 2020. For LF elimination, the World Health Organization (WHO) has proposed a comprehensive strategy including (i) interruption of LF transmission through large-scale annual treatment (or mass drug administration (MDA)) of all eligible individuals in endemic areas, and (ii) alleviation of LF-associated suffering through morbidity management and disability prevention. In Cameroon, once-yearly mass administration of ivermectin and albendazole has been implemented since 2008. The aim of this study was to assess progress towards the elimination goal, looking specifically at the impact of six rounds of MDA on LF transmission in northern Cameroon. METHODOLOGY The study was conducted in the North and Far North Regions of Cameroon. Five health districts that successfully completed six rounds of MDA (defined as achieving a treatment coverage ≥ 65% each year) and reported no positive results for Wuchereria bancrofti microfilariaemia during routine surveys following the fifth MDA were grouped into three evaluation units (EU) according to WHO criteria. LF transmission was assessed through a community-based transmission assessment survey (TAS) using an immunochromatographic test (ICT) for the detection of circulating filarial antigen (CFA) in children aged 5-8 years old. PRINCIPAL FINDINGS A total of 5292 children (male/female ratio 1.04) aged 5-8 years old were examined in 97 communities. Positive CFA results were observed in 2, 8 and 11 cases, with a CFA prevalence of 0.13% (95% CI: 0.04-0.46) in EU#1, 0.57% (95% CI: 0.32-1.02) in EU#2, and 0.45% (95% CI: 0.23-0.89) in EU#3. CONCLUSION/SIGNIFICANCE The positive CFA cases were below WHO defined critical cut-off thresholds for stopping treatment and suggest that transmission can no longer be sustained. Post-MDA surveillance activities should be organized to evaluate whether recrudescence can occur.
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Affiliation(s)
- Hugues C. Nana-Djeunga
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Magellan Tchouakui
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Guy R. Njitchouang
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
| | | | - Philippe Nwane
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
| | - André Domche
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Jean Bopda
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
| | | | - Julie Akame
- Helen Keller International, Yaoundé, Cameroon
| | - Ann Tarini
- Helen Keller International, Yaoundé, Cameroon
| | | | | | - Yaobi Zhang
- Helen Keller International, Regional Office for Africa, Dakar, Senegal
| | - Jean J. Tougoue
- RTI International, Washington, D.C., United States of America
| | - Achille Kabore
- RTI International, Washington, D.C., United States of America
| | - Flobert Njiokou
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon
| | - Joseph Kamgno
- Centre for Research on Filariasis and other Tropical Diseases, Yaoundé, Cameroon
- Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon
- * E-mail:
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20
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Masson J, Douglass J, Roineau M, Aye KS, Htwe KM, Warner J, Graves PM. Relative Performance and Predictive Values of Plasma and Dried Blood Spots with Filter Paper Sampling Techniques and Dilutions of the Lymphatic Filariasis Og4C3 Antigen ELISA for Samples from Myanmar. Trop Med Infect Dis 2017; 2:tropicalmed2020007. [PMID: 30270866 PMCID: PMC6082083 DOI: 10.3390/tropicalmed2020007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 03/27/2017] [Accepted: 04/04/2017] [Indexed: 01/24/2023] Open
Abstract
Diagnostic testing of blood samples for parasite antigen Og4C3 is used to assess Wuchereria bancrofti in endemic populations. However, the Tropbio ELISA recommends that plasma and dried blood spots (DBS) prepared using filter paper be used at different dilutions, making it uncertain whether these two methods and dilutions give similar results, especially at low levels of residual infection or resurgence during the post-program phase. We compared results obtained using samples of plasma and DBS taken simultaneously from 104 young adults in Myanmar in 2014, of whom 50 (48.1%) were positive for filariasis antigen by rapid antigen test. Results from DBS tests at recommended dilution were significantly lower than results from plasma tested at recommended dilution, with comparisons between plasma and DBS at unmatched dilutions yielding low sensitivity and negative predictive values of 60.0% and 70.6% respectively. While collection of capillary blood on DBS is cheaper and easier to perform than collecting plasma or serum, and does not need to be stored frozen, dilutions between different versions of the test must be reconciled or an adjustment factor applied.
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Affiliation(s)
- Jesse Masson
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD 4870, Australia.
| | - Jan Douglass
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD 4870, Australia.
| | - Maureen Roineau
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD 4870, Australia.
| | - Khin Saw Aye
- Department of Medical Research, Myanmar Ministry of Health and Sports, Nay Pyi Taw, Myanmar.
| | - Kyi May Htwe
- Department of Medical Research, Myanmar Ministry of Health and Sports, Nay Pyi Taw, Myanmar.
| | - Jeffrey Warner
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD 4870, Australia.
| | - Patricia M Graves
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Cairns, QLD 4870, Australia.
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21
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Njenga SM, Kanyi HM, Mutungi FM, Okoyo C, Matendechero HS, Pullan RL, Halliday KE, Brooker SJ, Wamae CN, Onsongo JK, Won KY. Assessment of lymphatic filariasis prior to re-starting mass drug administration campaigns in coastal Kenya. Parasit Vectors 2017; 10:99. [PMID: 28228160 PMCID: PMC5322668 DOI: 10.1186/s13071-017-2044-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 02/17/2017] [Indexed: 12/28/2022] Open
Abstract
Background Lymphatic filariasis (LF) is a debilitating disease associated with extensive disfigurement and is one of a diverse group of diseases referred to as neglected tropical diseases (NTDs) which mainly occur among the poorest populations. In line with global recommendations to eliminate LF, Kenya launched its LF elimination programme in 2002 with the aim to implement annual mass drug administration (MDA) in order to interrupt LF transmission. However, the programme faced financial and administrative challenges over the years such that sustained annual MDA was not possible. Recently, there has been renewed interest to eliminate LF and the Kenyan Ministry of Health, through support from World Health Organization (WHO), restarted annual MDA in 2015. The objective of this study was to evaluate the current status of LF infection in the endemic coastal region of Kenya before MDA campaigns were restarted. Results Ten sentinel sites in Kwale, Kilifi, Tana River, Lamu, and Taita-Taveta counties in coastal Kenya were selected for participation in a cross-sectional survey of LF infection prevalence. At least 300 individuals in each sentinel village were sampled through random house-to-house visits. During the day, the point-of-care immunochromatographic test (ICT) was used to detect the presence of Wuchereria bancrofti circulating filarial antigen in finger prick blood samples collected from residents of the selected sentinel villages. Those individuals who tested positive with the ICT test were requested to provide a night-time blood sample for microfilariae (MF) examination. The overall prevalence of filarial antigenaemia was 1.3% (95% CI: 0.9–1.8%). Ndau Island in Lamu County had the highest prevalence (6.3%; 95% CI: 4.1–9.7%), whereas sites in Kilifi and Kwale counties had prevalences < 1.7%. Mean microfilarial density was also higher in Ndau Island (234 MF/ml) compared to sentinel sites in Kwale and Kilifi counties (< 25 MF/ml). No LF infection was detected in Tana River and Taita-Taveta counties. Overall, more than 88% of the study participants reported to have used a bed net the previous night. Conclusions Prevalence of LF infection is generally very low in coastal Kenya, but there remain areas that require further rounds of MDA if the disease is to be eliminated as a public health problem in line with the ongoing global elimination efforts. However, areas where there was no evidence of LF transmission should be considered for WHO-recommended transmission assessment surveys in view of stopping MDA.
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Affiliation(s)
- Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya.
| | - Henry M Kanyi
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Faith M Mutungi
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | - Collins Okoyo
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Nairobi, Kenya
| | | | | | | | | | | | - Joyce K Onsongo
- Department of Microbiology, School of Medicine, Mount Kenya University, Thika, Kenya
| | - Kimberly Y Won
- Centers for Disease Control and Prevention, Atlanta, USA
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22
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Poole CB, Li Z, Alhassan A, Guelig D, Diesburg S, Tanner NA, Zhang Y, Evans TC, LaBarre P, Wanji S, Burton RA, Carlow CKS. Colorimetric tests for diagnosis of filarial infection and vector surveillance using non-instrumented nucleic acid loop-mediated isothermal amplification (NINA-LAMP). PLoS One 2017; 12:e0169011. [PMID: 28199317 PMCID: PMC5310896 DOI: 10.1371/journal.pone.0169011] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 11/19/2016] [Indexed: 11/26/2022] Open
Abstract
Accurate detection of filarial parasites in humans is essential for the implementation and evaluation of mass drug administration programs to control onchocerciasis and lymphatic filariasis. Determining the infection levels in vector populations is also important for assessing transmission, deciding when drug treatments may be terminated and for monitoring recrudescence. Immunological methods to detect infection in humans are available, however, cross-reactivity issues have been reported. Nucleic acid-based molecular assays offer high levels of specificity and sensitivity, and can be used to detect infection in both humans and vectors. In this study we developed loop-mediated isothermal amplification (LAMP) tests to detect three different filarial DNAs in human and insect samples using pH sensitive dyes for enhanced visual detection of amplification. Furthermore, reactions were performed in a portable, non-instrumented nucleic acid amplification (NINA) device that provides a stable heat source for LAMP. The efficacy of several strand displacing DNA polymerases were evaluated in combination with neutral red or phenol red dyes. Colorimetric NINA-LAMP assays targeting Brugia Hha I repeat, Onchocerca volvulus GST1a and Wuchereria bancrofti LDR each exhibit species-specificity and are also highly sensitive, detecting DNA equivalent to 1/10-1/5000th of one microfilaria. Reaction times varied depending on whether a single copy gene (70 minutes, O. volvulus) or repetitive DNA (40 min, B. malayi and W. bancrofti) was employed as a biomarker. The NINA heater can be used to detect multiple infections simultaneously. The accuracy, simplicity and versatility of the technology suggests that colorimetric NINA-LAMP assays are ideally suited for monitoring the success of filariasis control programs.
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Affiliation(s)
| | - Zhiru Li
- New England Biolabs, Ipswich, MA United States of America
| | - Andy Alhassan
- New England Biolabs, Ipswich, MA United States of America
| | - Dylan Guelig
- PATH, Seattle, Washington, United States of America
| | | | | | - Yinhua Zhang
- New England Biolabs, Ipswich, MA United States of America
| | | | - Paul LaBarre
- PATH, Seattle, Washington, United States of America
| | - Samuel Wanji
- Research Foundation in Tropical Diseases and Environment, Buea, Cameroon
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Lymphatic Filariasis Elimination in American Samoa: Evaluation of Molecular Xenomonitoring as a Surveillance Tool in the Endgame. PLoS Negl Trop Dis 2016; 10:e0005108. [PMID: 27802280 PMCID: PMC5089733 DOI: 10.1371/journal.pntd.0005108] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/13/2016] [Indexed: 11/19/2022] Open
Abstract
The Global Programme to Eliminate Lymphatic Filariasis has made significant progress toward interrupting transmission of lymphatic filariasis (LF) through mass drug administration (MDA). Operational challenges in defining endpoints of elimination programs include the need to determine appropriate post-MDA surveillance strategies. As humans are the only reservoirs of LF parasites, one such strategy is molecular xenomonitoring (MX), the detection of filarial DNA in mosquitoes using molecular methods (PCR), to provide an indirect indicator of infected persons nearby. MX could potentially be used to evaluate program success, provide support for decisions to stop MDA, and conduct post-MDA surveillance. American Samoa has successfully completed MDA and passed WHO recommended Transmission Assessment Surveys in 2011 and 2015, but recent studies using spatial analysis of antigen (Ag) and antibody (Ab) prevalence in adults (aged ≥18 years) and entomological surveys showed evidence of possible ongoing transmission. This study evaluated MX as a surveillance tool in American Samoa by linking village-level results of published human and mosquito studies. Of 32 villages, seropositive persons for Og4C3 Ag were identified in 11 (34.4%), for Wb123 Ab in 18 (56.3%) and for Bm14 Ab in 27 (84.4%) of villages. Village-level seroprevalence ranged from 0–33%, 0–67% and 0–100% for Og4C3 Ag, Wb123 Ab and Bm14 Ab respectively. PCR-positive Aedes polynesiensis mosquitoes were found in 15 (47%) villages, and their presence was significantly associated with seropositive persons for Og4C3 Ag (67% vs 6%, p<0.001) and Wb123 Ab (87% vs 29%, p = 0.001), but not Bm14 Ab. In villages with persons seropositive for Og4C3 Ag and Wb123 Ab, PCR-positive Ae. polynesiensis were found in 90.9% and 72.2% respectively. In villages without seropositive persons for Og4C3 Ag or Wb123 Ab, PCR-positive Ae. polynesiensis were also absent in 94.1% and 70.6% of villages respectively. Our study provides promising evidence to support the potential usefulness of MX in post-MDA surveillance in an Aedes transmission area in the Pacific Islands setting. Lymphatic filariasis (LF) is caused by infection with filarial worms that are transmitted by mosquito bites. Globally, 36 million are disfigured and disabled by complications such as severe swelling of the legs (elephantiasis) or scrotum (hydrocele). The Global Programme to Eliminate LF (GPELF) aims to interrupt disease transmission through mass drug administration (MDA), and to control illness and suffering in affected persons. Significant progress has been made toward eliminating LF from many parts of the world, including the Pacific Islands. Current challenges of the GPELF include identification of any residual hotspots of ongoing transmission, and effective strategies for early identification of any resurgence of infections. As humans are the only reservoirs of LF parasites and mosquitoes have short flight ranges, one such strategy is to monitor LF infection in mosquitoes as an indicator of ongoing transmission nearby. Mosquito monitoring could potentially be used to evaluate program success, provide support for decisions to stop MDA, and conduct post-MDA surveillance. Our study evaluated mosquito monitoring as a surveillance tool in American Samoa by linking village-level results of published studies of LF in humans and mosquitoes, and provides promising evidence to support the potential usefulness of mosquito monitoring in post-MDA surveillance the Pacific Islands.
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Jambulingam P, Subramanian S, de Vlas SJ, Vinubala C, Stolk WA. Mathematical modelling of lymphatic filariasis elimination programmes in India: required duration of mass drug administration and post-treatment level of infection indicators. Parasit Vectors 2016; 9:501. [PMID: 27624157 PMCID: PMC5022201 DOI: 10.1186/s13071-016-1768-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 08/22/2016] [Indexed: 12/03/2022] Open
Abstract
Background India has made great progress towards the elimination of lymphatic filariasis. By 2015, most endemic districts had completed at least five annual rounds of mass drug administration (MDA). The next challenge is to determine when MDA can be stopped. We performed a simulation study with the individual-based model LYMFASIM to help clarify this. Methods We used a model-variant for Indian settings. We considered different hypotheses on detectability of antigenaemia (Ag) in relation to underlying adult worm burden, choosing the most likely hypothesis by comparing the model predicted association between community-level microfilaraemia (Mf) and antigenaemia (Ag) prevalence levels to observed data (collated from literature). Next, we estimated how long MDA must be continued in order to achieve elimination in different transmission settings and what Mf and Ag prevalence may still remain 1 year after the last required MDA round. The robustness of key-outcomes was assessed in a sensitivity analysis. Results Our model matched observed data qualitatively well when we assumed an Ag detection rate of 50 % for single worm infections, which increases with the number of adult worms (modelled by relating detection to the presence of female worms). The required duration of annual MDA increased with higher baseline endemicity and lower coverage (varying between 2 and 12 rounds), while the remaining residual infection 1 year after the last required treatment declined with transmission intensity. For low and high transmission settings, the median residual infection levels were 1.0 % and 0.4 % (Mf prevalence in the 5+ population), and 3.5 % and 2.0 % (Ag prevalence in 6–7 year-old children). Conclusion To achieve elimination in high transmission settings, MDA must be continued longer and infection levels must be reduced to lower levels than in low-endemic communities. Although our simulations were for Indian settings, qualitatively similar patterns are also expected in other areas. This should be taken into account in decision algorithms to define whether MDA can be interrupted. Transmission assessment surveys should ideally be targeted to communities with the highest pre-control transmission levels, to minimize the risk of programme failure. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1768-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Purushothaman Jambulingam
- Vector Control Research Centre (Indian Council of Medical Research), Indira Nagar, Puducherry, 605006, India
| | - Swaminathan Subramanian
- Vector Control Research Centre (Indian Council of Medical Research), Indira Nagar, Puducherry, 605006, India.
| | - S J de Vlas
- Department of Public Health, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - Chellasamy Vinubala
- Vector Control Research Centre (Indian Council of Medical Research), Indira Nagar, Puducherry, 605006, India
| | - W A Stolk
- Department of Public Health, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands
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