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Soultani M, Bartlett AW, Mendes EP, Hii SF, Traub R, Palmeirim MS, Lufunda LMM, Colella V, Lopes S, Vaz Nery S. Estimating Prevalence and Infection Intensity of Soil-Transmitted Helminths Using Quantitative Polymerase Chain Reaction and Kato-Katz in School-Age Children in Angola. Am J Trop Med Hyg 2024; 110:1145-1151. [PMID: 38688261 PMCID: PMC11154060 DOI: 10.4269/ajtmh.23-0821] [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: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 05/02/2024] Open
Abstract
Quantitative polymerase chain reaction (qPCR) is gaining recognition in soil-transmitted helminth (STH) diagnostics, especially for Strongyloides stercoralis and differentiating hookworm species. However, sample preservation and DNA extraction may influence qPCR performance. We estimated STH prevalence and infection intensity by using qPCR in schoolchildren from Huambo, Uige, and Zaire, Angola, and compared its performance with that of the Kato-Katz technique (here termed Kato-Katz). Stool samples from 3,063 children (219 schools) were preserved in 96% ethanol and analyzed by qPCR, of which 2,974 children (215 schools) had corresponding Kato-Katz results. Cluster-adjusted prevalence and infection intensity estimates were calculated by qPCR and Kato-Katz, with cycle threshold values converted to eggs per gram for qPCR. Cohen's kappa statistic evaluated agreement between qPCR and Kato-Katz. DNA extraction and qPCR were repeated on 191 (of 278) samples that were initially qPCR negative but Kato-Katz positive, of which 112 (58.6%) became positive. Similar prevalence for Ascaris lumbricoides (37.5% versus 34.6%) and Trichuris trichiura (6.5% versus 6.1%) were found by qPCR and Kato-Katz, respectively, while qPCR detected a higher hookworm prevalence (11.9% versus 2.9%). The prevalence of moderate- or high-intensity infections was higher by Kato-Katz than by qPCR. Agreement between qPCR and Kato-Katz was very good for A. lumbricoides, moderate for T. trichiura, and fair for hookworm. Strongyloides stercoralis prevalence was 4.7% (municipality range, 0-14.3%), and no Ancylostoma ceylanicum was detected by qPCR. Despite suboptimal performance, presumably due to fixative choice, qPCR was fundamental in detecting S. stercoralis and excluding zoonotic A. ceylanicum. Further evaluations on sample fixatives and DNA extraction methods are needed to optimize and standardize the performance of qPCR.
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Affiliation(s)
- Muzhgan Soultani
- School of Population Health, University of New South Wales, Sydney, Australia
| | - Adam W. Bartlett
- Kirby Institute, University of New South Wales, Sydney, Australia
| | - Elsa P. Mendes
- National Directorate of Public Health, Ministry of Health, Luanda, Angola
| | - Sze Fui Hii
- Faculty of Science, University of Melbourne, Parkville, Australia
| | - Rebecca Traub
- Faculty of Science, University of Melbourne, Parkville, Australia
| | - Marta S. Palmeirim
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | | | - Vito Colella
- Faculty of Science, University of Melbourne, Parkville, Australia
| | | | - Susana Vaz Nery
- Kirby Institute, University of New South Wales, Sydney, Australia
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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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Le B, Clarke NE, Hii SF, Byrne A, Khattak A, Lake S, Lazu E, Wickham S, Wand H, Olsen N, Zendejas-Heredia PA, Sokana O, Romani L, Engelman D, Nasi T, Boara D, Kaldor J, Steer A, Traub R, Nery SV. Effectiveness of one and two doses of ivermectin mass drug administration in reducing the prevalence and intensity of soil-transmitted helminth (STH) infections in Western Province, Solomon Islands: a cluster-randomised, before-after analysis. THE LANCET REGIONAL HEALTH. WESTERN PACIFIC 2024; 42:100942. [PMID: 38357395 PMCID: PMC10865046 DOI: 10.1016/j.lanwpc.2023.100942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/23/2023] [Accepted: 10/09/2023] [Indexed: 02/16/2024]
Abstract
Background Ivermectin mass drug administration (MDA) is effective for controlling onchocerciasis and scabies, with evidence supporting its role in some species of soil-transmitted helminth (STH) infections. In the context of RISE, a cluster-randomised trial for scabies, this study evaluated the effectiveness of ivermectin MDA in reducing STH burden in the Western Province of Solomon Islands. Methods Twenty villages were randomised 1:1 to receive ivermectin MDA as one dose (IVM-1) or two doses (IVM-2) for scabies. The effectiveness of one and two doses in reducing STH prevalence and intensity was evaluated before (May 2019) and 21 months after (February 2021) MDA in May 2019. All residents aged 12 months or older in the study villages were eligible to participate and provide stool specimens. Species-specific STH infection and intensity were assessed using quantitative PCR. We compared prevalence and intensity of infection between baseline and 21 months in each intervention arm individually using cluster-level analysis (adjusted for clustering) and individual-level analysis (adjusted for sex, age, and clustering). The primary outcomes were the prevalence risk difference (RD) from the cluster-level analysis, and the change in adjusted odds of infection from the individual-level analysis. Secondary outcomes included change in incident rates of mean eggs per gram (epg) of stool from baseline to 21 months, relative risk difference in prevalence and relative change in odds of infection between arms at 21 months. Sex data (male/female) were self-reported. Findings Overall, STH infection was assessed in 830 participants from 18 villages at baseline and 1172 from 20 villages at follow-up. Females represented 58% (n = 478) of the sample at baseline and 59% (n = 690) at follow-up. We observed a reduction in Strongyloides spp. prevalence following two doses of ivermectin MDA in the cluster-level analysis from 7.0% (32/458 participants) to 1.2% (8/674 participants), corresponding to a RD of -0.07 (95% CI -0.14 to -0.01, p = 0.036), and in the individual-level analysis (OR 0.11, 95% CI 0.04-0.33, p < 0.001). T. trichiura prevalence decreased following one dose from 19.4% (74/372 participants) to 11.7% (56/505 participants) (OR 0.44, 95% CI 0.26-0.73, p = 0.0040), while egg count reduced in both arms (IVM-1: IRR 0.28, 95% CI 0.11-0.70, p = 0.0070; IVM-2: IRR 0.18, 95% CI 0.08-0.40, p < 0.001), in the individual-level analysis. We did not detect a significant difference in effect measures between the one- and two-dose arms for any species after 21 months. Interpretation Our study highlights the long-term benefits of ivermectin MDA in reducing the burden of Strongyloides spp. and T. trichiura. STH control programs should leverage the geographical overlap of NTDs, existing drug distribution channels, and broad-spectrum agents. Funding The National Health and Medical Research Council of Australia.
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Affiliation(s)
- Brandon Le
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Naomi E. Clarke
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Sze Fui Hii
- The University of Melbourne, Melbourne, Australia
| | - Aisling Byrne
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Alam Khattak
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Susanna Lake
- Murdoch Children's Research Institute, Melbourne, Australia
| | | | | | - Handan Wand
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Nick Olsen
- Stats Central, University of New South Wales, Sydney, Australia
| | | | - Oliver Sokana
- Ministry of Health & Medical Services, Honiara, Solomon Islands
| | - Lucia Romani
- The Kirby Institute, University of New South Wales, Sydney, Australia
- Murdoch Children's Research Institute, Melbourne, Australia
| | | | - Titus Nasi
- Ministry of Health & Medical Services, Honiara, Solomon Islands
| | | | - John Kaldor
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Andrew Steer
- Murdoch Children's Research Institute, Melbourne, Australia
| | | | - Susana Vaz Nery
- The Kirby Institute, University of New South Wales, Sydney, Australia
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Wisetmora A, Artchayasawat A, Laummaunwai P, Pitaksakulrat O, Wattanawong O, Boonmars T. Formalin-fixed stool improves the performance of the Kato-Katz method. Vet World 2024; 17:99-107. [PMID: 38406352 PMCID: PMC10884569 DOI: 10.14202/vetworld.2024.99-107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 12/14/2023] [Indexed: 02/27/2024] Open
Abstract
Background and Aim Parasitic infections are a public health problem worldwide, including in Thailand. An epidemiological survey for helminthiasis based on stool examination uses the Kato-Katz method as recommended by the World Health Organization. Limitations of this method include the need for fresh stool, time requirement, and lack of quality control. The aim of this study was to enhance the efficiency of the Kato-Katz technique using formalin and glycerol solutions and to implement specimen preparation in fieldwork. Materials and Methods For the Kato-Katz method, stool samples were divided into formalin-fixed and unfixed groups at various time points and processes. Fresh echinostome eggs were added to each stool group. Incubation with glycerol increased the clearing process. Each group was observed and photographed using a light microscope. Parasite eggs were imaged and compared using the standard Kato-Katz method. Results Visualization of echinostome eggs from formalin-fixed stool slides was significantly better than that from unfixed stool slides (p < 0.01). Stool samples fixed for 7 days retained normal echinostome eggs morphology. Incubation with glycerol for 1 h resulted in increased Kato-Katz performance by digesting the stool content and enhancing egg observation. Moreover, the results of the Kato-Katz method using fixed and fixed stool plus glycerol for natural helminth infection showed good quality of Opisthorchis viverrini and Taenia egg visualization and normal morphology with a clear background of slides. Conclusion Formalin-fixed stool could be more suitable than fresh stool for the Kato-Katz method.
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Affiliation(s)
- Ampas Wisetmora
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
- Division of General Communicable Diseases, Department of Disease Control, Ministry of Public Health, Nonthaburi, 11000, Thailand
| | - Atchara Artchayasawat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Porntip Laummaunwai
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Opal Pitaksakulrat
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Oranard Wattanawong
- Office of Diseases Prevention and Control 4 Saraburi, Ministry of Public Health, Saraburi, 18120, Thailand
| | - Thidarut Boonmars
- Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
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Dyer CE, Ng-Nguyen D, Clarke NE, Hii SF, Nguyen HQ, Nguyen VAT, Nguyen TV, Nguyen TV, Ngo TT, Herath HD, Wand H, Coffeng LE, Marshall JC, Gray DJ, Anderson RM, Clements AC, Kaldor JM, Traub RJ, Vaz Nery S. Community-wide versus school-based targeted deworming for soil-transmitted helminth control in school-aged children in Vietnam: the CoDe-STH cluster-randomised controlled trial. THE LANCET REGIONAL HEALTH. WESTERN PACIFIC 2023; 41:100920. [PMID: 37860203 PMCID: PMC10583164 DOI: 10.1016/j.lanwpc.2023.100920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Accepted: 09/15/2023] [Indexed: 10/21/2023]
Abstract
Background Soil-transmitted helminth (STH) infection control programs typically consist of school-based preventive chemotherapy (PC) targeted to school-aged children. STH reservoirs in untreated community members contribute to ongoing transmission in children. The CoDe-STH (Community Deworming against STH) trial, conducted in Dak Lak province, Vietnam, between October 2019 and November 2020, aimed to determine whether community-wide mass drug administration (MDA) is more effective than school-based targeted PC in reducing STH prevalence and intensity in children. Methods In this two-arm cluster randomised controlled trial, 64 primary schools were randomly assigned 1:1 to receive either school-based targeted PC ("school arm") or community-wide MDA ("community arm"). A single dose of albendazole 400 mg was used for deworming. The primary outcome was hookworm prevalence in schoolchildren, measured using quantitative real-time PCR. We also measured infection intensity for Necator americanus only, using qPCR cycle threshold (Ct) values converted into eggs per gram of faeces (EPG). Analysis was by intention to treat. The trial was registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619000309189). Findings The analysis included 4955 children in the school arm and 5093 children in the community arm. N. americanus was the dominant STH species. The relative reduction in hookworm prevalence was not significantly different between the school arm (30.1%, 95% confidence interval [CI] 20.5-36.9) and the community arm (34.6%, 95% CI 19.9-49.4). Due to lower baseline prevalence than expected, the study was underpowered to detect a difference in prevalence reduction between the study arms. The community arm showed significantly greater relative reduction in N. americanus infection intensity (56.0%, 95% CI 39.9-72.1) compared to the school arm (3.4%, 95% CI -24.7 to 31.4). The community arm also showed greater relative reduction in prevalence of moderate-to-heavy intensity (≥2000 EPG) N. americanus infections (81.1%; 95% CI 69.7-92.6) compared to the school arm (39.0%, 95% CI 13.7-64.2). Interpretation Although no impact was seen on overall prevalence, community-wide MDA was more effective in lowering N. americanus infection intensity in schoolchildren compared to school-based targeted PC, measured 12 months after one round of albendazole deworming with high coverage. Funding National Health and Medical Research Council, Australia (APP1139561).
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Affiliation(s)
- Clare E.F. Dyer
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Dinh Ng-Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Dak Lak, Vietnam
| | - Naomi E. Clarke
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Sze Fui Hii
- Faculty of Science, Melbourne Veterinary School, The University of Melbourne, Melbourne, Vic, Australia
| | - Hieu Quoc Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Dak Lak, Vietnam
| | - Van-Anh Thi Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Dak Lak, Vietnam
| | - Thai Van Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Dak Lak, Vietnam
| | - Trong Van Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Dak Lak, Vietnam
| | - Tam Thi Ngo
- Centers for Disease Control and Prevention, Dak Lak, Vietnam
| | - H.M.P. Dilrukshi Herath
- Faculty of Science, Melbourne Veterinary School, The University of Melbourne, Melbourne, Vic, Australia
| | - Handan Wand
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Luc E. Coffeng
- Department of Public Health, Erasmus MC, University Medical Center Rotterdam, Rotterdam, the Netherlands
| | | | - Darren J. Gray
- Research School of Population Health, Australian National University, Canberra, ACT, Australia
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Roy M. Anderson
- Faculty of Medicine, School of Public Health, Imperial College London, London, United Kingdom
| | - Archie C.A. Clements
- Faculty of Health Sciences, Curtin University, Perth, WA, Australia
- Telethon Kids Institute, Perth, WA, Australia
- Peninsula Medical School, University of Plymouth, Plymouth, United Kingdom
| | - John M. Kaldor
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Rebecca J. Traub
- Faculty of Science, Melbourne Veterinary School, The University of Melbourne, Melbourne, Vic, Australia
| | - Susana Vaz Nery
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
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Leutenegger CM, Lozoya CE, Tereski J, Andrews J, Mitchell KD, Meeks C, Willcox JL, Freeman G, Richmond HL, Savard C, Evason MD. Comparative study of a broad qPCR panel and centrifugal flotation for detection of gastrointestinal parasites in fecal samples from dogs and cats in the United States. Parasit Vectors 2023; 16:288. [PMID: 37587483 PMCID: PMC10433665 DOI: 10.1186/s13071-023-05904-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/27/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND For decades, zinc sulfate centrifugal fecal flotation microscopy (ZCF) has been the mainstay technique for gastrointestinal (GI) parasite screening at veterinary clinics and laboratories. Elsewhere, PCR has replaced microscopy because of generally increased sensitivity and detection capabilities; however, until recently it has been unavailable commercially. Therefore, the primary aim of this study was to compare the performance of real-time PCR (qPCR) and ZCF for fecal parasite screening. Secondary aims included further characterization of markers for hookworm treatment resistance and Giardia spp. assemblages with zoonotic potential and qPCR optimization. METHODS A convenience sampling of 931 canine/feline fecal samples submitted to a veterinary reference laboratory for routine ZCF from the Northeast US (11/2022) was subsequently evaluated by a broad qPCR panel following retention release. Detection frequency and agreement (kappa statistics) were evaluated between ZCF and qPCR for seven GI parasites [hookworm/(Ancylostoma spp.), roundworm/(Toxocara spp.), whipworm/(Trichuris spp.), Giardia duodenalis, Cystoisospora spp., Toxoplasma gondii, and Tritrichomonas blagburni] and detections per sample. Total detection frequencies were compared using a paired t-test; positive sample and co-infection frequencies were compared using Pearson's chi-squared test (p ≤ 0.05 significant) and qPCR frequency for hookworm benzimidazole (BZ) resistance (F167Y) and zoonotic Giardia spp. assemblage markers calculated. Confirmatory testing, characterization, and qPCR optimization were carried out with Sanger sequencing. RESULTS qPCR detected a significantly higher overall parasite frequency (n = 679) compared to ZCF (n = 437) [p = < 0.0001, t = 14.38, degrees-of-freedom (df) = 930] and 2.6 × the co-infections [qPCR (n = 172) vs. ZCF (n = 66)], which was also significant (p = < 0.0001, X2 = 279.49; df = 1). While overall agreement of parasite detection was substantial [kappa = 0.74; (0.69-0.78], ZCF-undetected parasites reduced agreement for individual and co-infected samples. qPCR detected markers for Ancylostoma caninum BZ resistance (n = 5, 16.1%) and Giardia with zoonotic potential (n = 22, 9.1%) as well as two parasites undetected by ZCF (T. gondii/T. blagburni). Sanger sequencing detected novel roundworm species, and qPCR optimization provided detection beyond ZCF. CONCLUSIONS These results demonstrate the statistically significant detection frequency advantage offered by qPCR compared to routine ZCF for both single and co-infections. While overall agreement was excellent, this rapid, commercially available qPCR panel offers benefits beyond ZCF with detection of markers for Giardia assemblages with zoonotic potential and hookworm (A. caninum) BZ resistance.
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Affiliation(s)
| | | | | | - Jan Andrews
- Antech Diagnostics, Inc, Fountain Valley, CA, USA
| | | | - Cathy Meeks
- Antech Diagnostics, Inc, Fountain Valley, CA, USA
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Pierce DR, McDonald M, Merone L, Becker L, Thompson F, Lewis C, Ryan RYM, Hii SF, Zendejas-Heredia PA, Traub RJ, Field MA, Rahman T, Croese J, Loukas A, McDermott R, Giacomin PR. Effect of experimental hookworm infection on insulin resistance in people at risk of type 2 diabetes. Nat Commun 2023; 14:4503. [PMID: 37495576 PMCID: PMC10372076 DOI: 10.1038/s41467-023-40263-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 07/19/2023] [Indexed: 07/28/2023] Open
Abstract
The reduced prevalence of insulin resistance and type 2 diabetes in countries with endemic parasitic worm infections suggests a protective role for worms against metabolic disorders, however clinical evidence has been non-existent. This 2-year randomised, double-blinded clinical trial in Australia of hookworm infection in 40 male and female adults at risk of type 2 diabetes assessed the safety and potential metabolic benefits of treatment with either 20 (n = 14) or 40 (n = 13) Necator americanus larvae (L3) or Placebo (n = 13) (Registration ACTRN12617000818336). Primary outcome was safety defined by adverse events and completion rate. Homoeostatic model assessment of insulin resistance, fasting blood glucose and body mass were key secondary outcomes. Adverse events were more frequent in hookworm-treated participants, where 44% experienced expected gastrointestinal symptoms, but completion rates were comparable to Placebo. Fasting glucose and insulin resistance were lowered in both hookworm-treated groups at 1 year, and body mass was reduced after L3-20 treatment at 2 years. This study suggests hookworm infection is safe in people at risk of type 2 diabetes and associated with improved insulin resistance, warranting further exploration of the benefits of hookworms on metabolic health.
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Affiliation(s)
- Doris R Pierce
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Malcolm McDonald
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Lea Merone
- College of Health Sciences, James Cook University, Cairns, QLD, Australia
| | - Luke Becker
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Fintan Thompson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
- University of South Australia, Adelaide, SA, Australia
| | - Chris Lewis
- College of Health Sciences, James Cook University, Cairns, QLD, Australia
| | - Rachael Y M Ryan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Sze Fui Hii
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Parkville, VIC, Australia
| | - Patsy A Zendejas-Heredia
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Parkville, VIC, Australia
| | - Rebecca J Traub
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Parkville, VIC, Australia
| | - Matthew A Field
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
- College of Public Health, Medical & Vet Sciences, James Cook University, Cairns, QLD, Australia
- Immunogenomics Laboratory, Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
| | - Tony Rahman
- The Department of Gastroenterology and Hepatology, The Prince Charles Hospital, Brisbane, QLD, Australia
| | - John Croese
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Robyn McDermott
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
- University of South Australia, Adelaide, SA, Australia
| | - Paul R Giacomin
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia.
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Hughes A, Ng-Nguyen D, Clarke NE, Dyer CEF, Hii SF, Clements ACA, Anderson RM, Gray DJ, Coffeng LE, Kaldor JM, Traub RJ, Vaz Nery S. Epidemiology of soil-transmitted helminths using quantitative PCR and risk factors for hookworm and Necator americanus infection in school children in Dak Lak province, Vietnam. Parasit Vectors 2023; 16:213. [PMID: 37370075 DOI: 10.1186/s13071-023-05809-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 05/14/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Soil-transmitted helminth (STH) infection is driven by a complex interaction of demographic, socioeconomic and behavioural factors, including those related to water, sanitation and hygiene (WASH). Epidemiological studies that measure both infection and potential risk factors associated with infection help to understand the drivers of transmission in a population and therefore can provide information to optimise STH control programmes. METHODS During October and November 2019, we conducted a cross-sectional survey of the prevalence and intensity of STH infection and associated risk factors among 7710 primary-school-age children from 64 primary schools across 13 districts in Dak Lak province, Vietnam. Quantitative PCR (qPCR) was used to detect and quantify STH infections. RESULTS The predominant STH species was the hookworm Necator americanus (overall cluster-adjusted prevalence of 13.7%), and its prevalence was heterogeneously distributed across surveyed schools (0% to 56.3%). All other STH species had a prevalence of less than 1%. Using mixed-effects logistic regression, we found that the adjusted odds ratio (aOR) was significantly higher for both infection and moderate-to-heavy-intensity infection with N. americanus among children from multiple ethnic minority groups, compared to children from the majority group (Kinh). Adjusted odds of infection with N. americanus were also higher in children who reported practising open defecation at school (aOR 1.42, 95% CI 1.05, 1.93, P = 0.02) and in those who had an unimproved household water supply (aOR 1.28, 95% CI 1.04, 1.57, P = 0.02). Conversely, children with a flushing household toilet had a reduced risk of infection (aOR 0.58, 95% CI 0.47, 0.70, P < 0.01), as did those whose primary female carer attended secondary (aOR 0.65, 95% CI 0.51, 0.84, P < 0.01) or tertiary education (aOR 0.39, 95% CI 0.24, 0.63, P < 0.01). CONCLUSIONS This study is the largest reported prevalence survey of STH infections conducted using qPCR as a diagnostic technique. The findings of higher adjusted odds of infection amongst ethnic minority children highlight that STH control programmes may not be reaching certain population groups and that additional culturally appropriate approaches may be required. Additionally, the associations between specific WASH factors and infection indicate potential programmatic targets to complement preventive chemotherapy programmes.
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Affiliation(s)
- Angus Hughes
- School of Population Health, University of New South Wales, Sydney, Australia.
| | - Dinh Ng-Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Buon Ma Thuot, Dak Lak, Vietnam
| | - Naomi E Clarke
- The Kirby Institute for Infection and Immunity in Society, University of New South Wales, Sydney, Australia
| | - Clare E F Dyer
- The Kirby Institute for Infection and Immunity in Society, University of New South Wales, Sydney, Australia
| | - Sze Fui Hii
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Australia
| | - Archie C A Clements
- Faculty of Health Sciences, Curtin University, Perth, Australia
- Telethon Kids Institute, Perth, Australia
| | - Roy M Anderson
- Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
| | - Darren J Gray
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Luc E Coffeng
- Department of Public Health, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - John M Kaldor
- The Kirby Institute for Infection and Immunity in Society, University of New South Wales, Sydney, Australia
| | - Rebecca J Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Australia
| | - Susana Vaz Nery
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Buon Ma Thuot, Dak Lak, Vietnam
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9
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Ferreira SCM, Jarquín-Díaz VH, Heitlinger E. Amplicon sequencing allows differential quantification of closely related parasite species: an example from rodent Coccidia (Eimeria). Parasit Vectors 2023; 16:204. [PMID: 37330545 DOI: 10.1186/s13071-023-05800-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/03/2023] [Indexed: 06/19/2023] Open
Abstract
BACKGROUND Quantifying infection intensity is a common goal in parasitological studies. We have previously shown that the amount of parasite DNA in faecal samples can be a biologically meaningful measure of infection intensity, even if it does not agree well with complementary counts of transmission stages (oocysts in the case of Coccidia). Parasite DNA can be quantified at relatively high throughput using quantitative polymerase chain reaction (qPCR), but amplification needs a high specificity and does not simultaneously distinguish between parasite species. Counting of amplified sequence variants (ASVs) from high-throughput marker gene sequencing using a relatively universal primer pair has the potential to distinguish between closely related co-infecting taxa and to uncover the community diversity, thus being both more specific and more open-ended. METHODS We here compare qPCR to the sequencing-based amplification using standard PCR and a microfluidics-based PCR to quantify the unicellular parasite Eimeria in experimentally infected mice. We use multiple amplicons to differentially quantify Eimeria spp. in a natural house mouse population. RESULTS We show that sequencing-based quantification has high accuracy. Using a combination of phylogenetic analysis and the co-occurrence network, we distinguish three Eimeria species in naturally infected mice based on multiple marker regions and genes. We investigate geographical and host-related effects on Eimeria spp. community composition and find, as expected, prevalence to be largely explained by sampling locality (farm). Controlling for this effect, the novel approach allowed us to find body condition of mice to be negatively associated with Eimeria spp. abundance. CONCLUSIONS We conclude that amplicon sequencing provides the underused potential for species distinction and simultaneous quantification of parasites in faecal material. The method allowed us to detect a negative effect of Eimeria infection on the body condition of mice in the natural environment.
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Affiliation(s)
- Susana C M Ferreira
- Division of Computational Systems Biology, Center for Microbiology and Ecological Systems Science, University of Vienna, Djerassipl. 1, 1030, Vienna, Austria.
- Institute for Biology. Department of Molecular Parasitology, Humboldt-Universität zu Berlin (HU), Philippstr. 13, Haus 14, 10115, Berlin, Germany.
| | - Víctor Hugo Jarquín-Díaz
- Institute for Biology. Department of Molecular Parasitology, Humboldt-Universität zu Berlin (HU), Philippstr. 13, Haus 14, 10115, Berlin, Germany
- Leibniz-Institut Für Zoo- Und Wildtierforschung (IZW) im Forschungsverbund Berlin E.V., Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
- Experimental and Clinical Research Center, a cooperation between the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and the Charité - Universitätsmedizin Berlin, Berlin, Germany
- Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Lindenberger Weg 80, 13125, Berlin, Germany
- Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Emanuel Heitlinger
- Institute for Biology. Department of Molecular Parasitology, Humboldt-Universität zu Berlin (HU), Philippstr. 13, Haus 14, 10115, Berlin, Germany
- Leibniz-Institut Für Zoo- Und Wildtierforschung (IZW) im Forschungsverbund Berlin E.V., Alfred-Kowalke-Straße 17, 10315, Berlin, Germany
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10
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Le B, Monteiro MAA, Amaral S, Wand H, Matthews A, Hii SF, Clarke NE, Arkell P, Yan J, Engelman D, Fancourt N, Fernandes JL, Steer A, Kaldor J, Traub R, Francis JR, Nery SV. The impact of ivermectin, diethylcarbamazine citrate, and albendazole mass drug administration on the prevalence of scabies and soil-transmitted helminths in school-aged children in three municipalities in Timor-Leste: a before-after assessment. Lancet Glob Health 2023; 11:e924-e932. [PMID: 37202027 DOI: 10.1016/s2214-109x(23)00134-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 02/07/2023] [Accepted: 02/27/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND Integrated programmes that use combination mass drug administration (MDA) might improve control of multiple neglected tropical diseases simultaneously. We investigated the impact of Timor-Leste's national ivermectin, diethylcarbamazine citrate, and albendazole MDA, for lymphatic filariasis elimination and soil-transmitted helminth (STH) control, on scabies, impetigo, and STH infections. METHODS We did a before-after study in six primary schools across three municipalities in Timor-Leste (urban [Dili], semi-urban [Ermera], and rural [Manufahi]) before (April 23 to May 11, 2019) and 18 months after (Nov 9 to Nov 27, 2020) MDA delivery between May 17 and June 1, 2019. Study participants included schoolchildren, as well as infants, children, and adolescents who were incidentally present at school on study days. All schoolchildren whose parents provided consent were eligible to participate in the study. Infants, children, and adolescents younger than 19 years who were not enrolled in the school but were incidentally present at schools on study days were also eligible to participate if their parents consented. Ivermectin, diethylcarbamazine citrate, and albendazole MDA was implemented nationally, with single doses of oral ivermectin (200 μg/kg), diethylcarbamazine citrate (6 mg/kg), and albendazole (400 mg) administered by the Ministry of Health. Scabies and impetigo were assessed by clinical skin examinations, and STHs using quantitative PCR. The primary (cluster-level) analysis adjusted for clustering while the secondary (individual-level) analysis adjusted for sex, age, and clustering. The primary outcomes of the study were prevalence ratios for scabies, impetigo, and STHs (Trichuris trichiura, Ascaris lumbricoides, Necator americanus, and moderate-to-heavy A lumbricoides infections) between baseline and 18 months from the cluster-level analysis. FINDINGS At baseline, 1043 (87·7%) of 1190 children registered for the study underwent clinical assessment for scabies and impetigo. The mean age of those who completed skin examinations was 9·4 years (SD 2·4) and 514 (53·8%) of 956 were female (87 participants with missing sex data were excluded from this percentage calculation). Stool samples were received for 541 (45·5%) of 1190 children. The mean age of those for whom stool samples were received was 9·8 years (SD 2·2) and 300 (55·5%) were female. At baseline, 348 (33·4%) of 1043 participants had scabies, and 18 months after MDA, 133 (11·1%) of 1196 participants had scabies (prevalence ratio 0·38, 95% CI 0·18-0·88; p=0·020) in the cluster-level analysis. At baseline, 130 (12·5%) of 1043 participants had impetigo, compared with 27 (2·3%) of 1196 participants at follow-up (prevalence ratio 0·14, 95% CI 0·07-0·27; p<0·0001). There was a significant reduction in T trichiura prevalence from baseline (26 [4·8%] of 541 participants) to 18-month follow-up (four [0·6%] of 623 participants; prevalence ratio 0·16, 95% CI 0·04-0·66; p<0·0001). In the individual-level analysis, moderate-to-heavy A lumbricoides infections reduced from 54 (10·0%; 95% CI 0·7-19·6) of 541 participants to 28 (4·5%, 1·2-8·4) of 623 participants (relative reduction 53·6%; 95% CI 9·1-98·1; p=0·018). INTERPRETATION Ivermectin, diethylcarbamazine citrate, and albendazole MDA was associated with substantial reductions in prevalence of scabies, impetigo, and T trichiura, and of moderate-to-heavy intensity A lumbricoides infections. Combination MDA could be used to support integrated control programmes to target multiple NTDs. FUNDING National Health and Medical Research Council of Australia and the Department of Foreign Affairs and Trade Indo-Pacific Centre for Health Security. TRANSLATION For the Tetum translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Brandon Le
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia.
| | | | - Salvador Amaral
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Handan Wand
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | | | - Sze Fui Hii
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Naomi E Clarke
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Paul Arkell
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Jennifer Yan
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Daniel Engelman
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - Nicholas Fancourt
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | | | - Andrew Steer
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
| | - John Kaldor
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Rebecca Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Joshua R Francis
- Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Susana Vaz Nery
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
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11
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Ding X, Yang Y, Zhang Y, Zhang Q, Mao F, Dai Y. Establishment of a Simple and Rapid Nucleic Acid Detection Method for Hookworm Identification. Pathogens 2023; 12:pathogens12040630. [PMID: 37111516 PMCID: PMC10142964 DOI: 10.3390/pathogens12040630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
Hookworm infection is one of the most common neglected tropical diseases and is mainly found in tropical and subtropical areas. Two species of human hookworm are distributed in China, i.e., Ancylostoma duodenale (AD) and Necator americanus (NA). BACKGROUND Traditional microscopic technology such as the Kato-Katz method is not suitable for hookworm diagnosis due to the rapid degeneration of fragile hookworm eggs or for species identification of hookworm infection. The aim of the present study was to establish and evaluate a novel nucleic acid detection method based on recombinase-aided isothermal amplification (RAA) for the detection of hookworm infections and species identification. METHODS Based on the specific target gene sequences of hookworms (5.8S rRNA for AD and ITS2 for NA, respectively), we designed and synthesized amplification primers and fluorescence probes referring to the principle of the fluorescence recombinase-aided amplification (RAA) technique. RESULTS Each assay provided specific amplification of larval DNA from AD and NA by fluorescence RAA, and the detection limits in plasmids reached 102 copies and 10 copies, respectively. Genomic DNA of two hookworm species was successfully detected at a concentration of 0.1 pg/μL, revealing a high detection sensitivity. No positive amplification occurred for genomic DNA from crossed hookworm species and genomic DNA from Cryptosporidium, Giardia lamblia, Strongyloides stercoralis, Schistosoma japonicum, Ascaris lumbricoides, and Clonorchis sinensis, revealing a satisfactory specificity. Fecal sample detection results demonstrated a similar efficacy to the Kato-Katz method; however, it had a greater sensitivity than the larvae culture method. CONCLUSION A simple and rapid nucleic acid method was successfully established based on RAA, which improved the detection efficacy and species identification for human hookworm infections.
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Affiliation(s)
- Xin Ding
- Key Laboratory of National Health Commission on Parasitic Disease Control and Prevention, Key Laboratory of Jiangsu Province on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi 214064, China
| | - Yougui Yang
- School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Yingshu Zhang
- School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Qiang Zhang
- Key Laboratory of National Health Commission on Parasitic Disease Control and Prevention, Key Laboratory of Jiangsu Province on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi 214064, China
| | - Fanzhen Mao
- Key Laboratory of National Health Commission on Parasitic Disease Control and Prevention, Key Laboratory of Jiangsu Province on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi 214064, China
| | - Yang Dai
- Key Laboratory of National Health Commission on Parasitic Disease Control and Prevention, Key Laboratory of Jiangsu Province on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi 214064, China
- School of Public Health, Nanjing Medical University, Nanjing 211166, China
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12
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Walker M, Lambert S, Neves MI, Worsley AD, Traub R, Colella V. Modeling the effectiveness of One Health interventions against the zoonotic hookworm Ancylostoma ceylanicum. Front Med (Lausanne) 2023; 10:1092030. [PMID: 36960338 PMCID: PMC10028197 DOI: 10.3389/fmed.2023.1092030] [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: 11/07/2022] [Accepted: 02/14/2023] [Indexed: 03/09/2023] Open
Abstract
Hookworm disease is a major global public health concern, annually affecting 500-700 million of the world's poorest people. The World Health Organization is targeting the elimination of hookworm as a public health problem by 2030 using a strategy of mass drug administration (MDA) to at-risk human populations. However, in Southeast Asia and the Pacific the zoonotic hookworm species, Ancylostoma ceylanicum, is endemic in dogs and commonly infects people. This presents a potential impediment to the effectiveness of MDA that targets only humans. Here, we develop a novel multi-host (dog and human) transmission model of A. ceylanicum and compare the effectiveness of human-only and "One Health" (human plus dog) MDA strategies under a range of eco-epidemiological assumptions. We show that One Health interventions-targeting both dogs and humans-could suppress prevalence in humans to ≤ 1% by the end of 2030, even with only modest coverage (25-50%) of the animal reservoir. With increasing coverage, One Health interventions may even interrupt transmission. We discuss key unresolved questions on the eco-epidemiology of A. ceylanicum, the challenges of delivering MDA to animal reservoirs, and the growing importance of One Health interventions to human public health.
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Affiliation(s)
- Martin Walker
- Department of Pathobiology and Populations Sciences, Royal Veterinary College, Hatfield, United Kingdom
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, Imperial College London, London, United Kingdom
- *Correspondence: Martin Walker
| | - Sébastien Lambert
- Department of Pathobiology and Populations Sciences, Royal Veterinary College, Hatfield, United Kingdom
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, Imperial College London, London, United Kingdom
- IHAP, INRAE, ENVT, Université de Toulouse, Toulouse, France
| | - M. Inês Neves
- Department of Pathobiology and Populations Sciences, Royal Veterinary College, Hatfield, United Kingdom
- Department of Infectious Disease Epidemiology, London Centre for Neglected Tropical Disease Research, Imperial College London, London, United Kingdom
| | - Andrew D. Worsley
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Rebecca Traub
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Vito Colella
- Department of Veterinary Biosciences, The University of Melbourne, Melbourne, VIC, Australia
- Vito Colella
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13
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Advantages and Limitations of Microscopy and Molecular Detections for Diagnosis of Soil-transmitted Helminths: An Overview. Helminthologia 2022; 59:321-340. [PMID: 36875683 PMCID: PMC9979072 DOI: 10.2478/helm-2022-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 10/31/2022] [Indexed: 02/05/2023] Open
Abstract
World Health Organization (WHO) reported that over 1.5 billion people are infected by soil-transmitted helminths (STH) worldwide in sub-Saharan Africa, the United States of America, China, and East Asia. Heavy infections and polyparasitism are associated with higher morbidity rates, and the patients are exposed to increased vulnerability to other diseases. Therefore, accurate diagnosis followed by mass treatment for morbidity control is necessary.STH diagnosis commonly involves the microscopic observation of the presence of the STH eggs and larvae in the faecal samples. Furthermore, molecular approaches are increasingly utilised in monitoring and surveillance as they show higher sensitivity. Their capability to differentiate hookworm species is an advantage over the Kato-Katz technique. This review discusses the advantages and limitations of microscopy and various molecular tools used for STH detection.
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14
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Gomes ECDS, Barbosa Júnior WL, Melo FLD. Evaluation of SmITS1-LAMP performance to diagnosis schistosomiasis in human stool samples from an endemic area in Brazil. Exp Parasitol 2022; 242:108389. [DOI: 10.1016/j.exppara.2022.108389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/09/2022] [Accepted: 09/21/2022] [Indexed: 11/04/2022]
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15
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Dyer CEF, Clarke NE, Nguyen DN, Herath HMPD, Hii SF, Pickford R, Traub RJ, Vaz Nery S. Assessing the efficacy of albendazole against hookworm in Vietnam using quantitative PCR and sodium nitrate flotation. PLoS Negl Trop Dis 2022; 16:e0010767. [PMID: 36315591 PMCID: PMC9668116 DOI: 10.1371/journal.pntd.0010767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 11/16/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
Preventive chemotherapy (PC), consisting of the regular distribution of anthelmintics to populations or groups of populations at risk, is the primary tool used to control soil-transmitted helminth (STH) infections. This strategy, whilst cost-effective, raises the concern of potential emergence of drug resistance. The efficacy of anthelmintics against STH infections is measured using cure rate (CR) and egg reduction rate (ERR), using microscopy-based techniques such as the Kato-Katz thick smear. However, Kato-Katz has low sensitivity, especially for low-intensity infections, and requires fresh samples that need to be processed quickly. Realtime quantitative PCR (qPCR), which is more sensitive, is emerging as a "gold standard" for STH diagnostics given its higher sensitivity (important in low prevalence settings) and ability to differentiate hookworm species, while sodium nitrate flotation (SNF) may provide a low-cost more sensitive and practical alternative to Kato-Katz in the field. In this study, we examined the efficacy of a locally manufactured brand of albendazole 400 mg ("Alzental") against hookworm in Đắk Lắk province, Vietnam, using both qPCR and SNF. For qPCR, formulae to convert qPCR cycle threshold (Ct) values into eggs per gram of faeces (EPG) were utilised to determine efficacy calculations, and these values directly compared with efficacy values generated using SNF. Factors associated with CR and ERR were examined, and Alzental tablet quality was assessed by comparing with an Australian TGA-approved equivalent "Eskazole" tablet. We observed a CR and ERR of 64.9% and 87.5% respectively using qPCR, and 68.4% and 67.6% respectively using SNF. The tablet composition of Alzental was comparable to Eskazole in terms of active albendazole drug concentration with no evidence of impurities. This study demonstrates that the efficacy of Alzental against hookworm is within the range of previously reported studies for albendazole 400 mg. The study also demonstrates the value of qPCR and SNF as alternatives to standard Kato-Katz methodology for assessment of anthelmintic efficacy.
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Affiliation(s)
- Clare E. F. Dyer
- Kirby Institute, University of New South Wales, Sydney, Australia
- * E-mail:
| | - Naomi E. Clarke
- Kirby Institute, University of New South Wales, Sydney, Australia
| | - Dinh Ng Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, Đắk Lắk, Vietnam
| | | | - Sze Fui Hii
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Victoria, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, University of New South Wales Analytical Centre, Sydney, Australia
| | - Rebecca J. Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Victoria, Australia
| | - Susana Vaz Nery
- Kirby Institute, University of New South Wales, Sydney, Australia
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16
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Potentials and challenges in the isolation and detection of ascarid eggs in complex environmental matrices. Food Waterborne Parasitol 2022; 28:e00174. [PMID: 36017135 PMCID: PMC9396397 DOI: 10.1016/j.fawpar.2022.e00174] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 07/05/2022] [Accepted: 08/01/2022] [Indexed: 11/22/2022] Open
Abstract
Ascarid infections constitute a major concern for both human and animal health risk assessment. Although being effectively transmitted by soil, water and contaminated food, reliable detection of ascarid eggs in environmental media often remains challenging. However, contamination of the environment with ascarid ova has gained more attention as a decisive part of proper risk assessment in recent years. Due to various factors, such as sample matrices, dissociation detergents and flotation solutions, defined and standardised protocols for the isolation of eggs from complex environmental matrices are difficult to establish and therefore limited. Thus, this study reviews common techniques used for the recovery of ascarid eggs from environmental media with special emphasis on sampling strategies, purification procedures and microscopic as well as molecular detection of egg contamination. Despite various advancements, mainly in the field of molecular methods leading to more reliable and sensitive detection, it can be concluded that there is still a need for unified guidelines for sampling and recovery of ascarid eggs derived from complex environmental matrices. Standardised methods to assess environmental ascarid egg contamination are needed. The environmental sampling strategy has to be adapted to the study hypothesis. Egg detection mostly relies on matrix homogenisation, filtration, sedimentation and flotation. Microscopic detection is still frequently applied. Molecular methods enable more reliable and sensitive detection.
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17
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Massetti L, Wiethoelter A, McDonagh P, Rae L, Marwedel L, Beugnet F, Colella V, Traub RJ. Faecal prevalence, distribution and risk factors associated with canine soil-transmitted helminths contaminating urban parks across Australia. Int J Parasitol 2022; 52:637-646. [PMID: 36007621 DOI: 10.1016/j.ijpara.2022.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 08/08/2022] [Accepted: 08/15/2022] [Indexed: 11/18/2022]
Abstract
Dog parks provide an ideal urban space where dogs and their owners can exercise, play, and socialize in a safe environment. However, these parks can also increase the risk of exposure to a series of infectious agents including canine soil-transmitted helminths (cSTHs) such as hookworms, roundworms, Strongyloides stercoralis, and Trichuris vulpis, which are endemic to Australia. In this study, we collected 1581 canine faecal samples in 190 urban parks across Australia and subjected these to faecal floatation and multiplex real-time PCRs (qPCR) to detect a range of cSTHs. In total, 44.2% of the parks sampled were contaminated with at least one species of cSTH, with hookworms being the most prevalent parasites (10.2%) followed by Trichuris spp. (1.3%) and Strongyloides spp. (1.2%). This is the first large-scale study investigating the contamination of urban parks with cSTHs in Australia, and the first nation-wide study to demonstrate the occurrence of Strongyloides spp. in canine faecal samples from urban areas in the country. This study reveals a high rate of contamination with cSTHs in dog parks in urban Australia, most of which having proven zoonotic potential. Preventive measures, including awareness-raising educational programs promoting responsible pet ownership, should be encouraged to minimise the health risks associated with cSTHs for both dogs and humans.
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Affiliation(s)
- Luca Massetti
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC3052, Australia.
| | - Anke Wiethoelter
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC3052, Australia
| | - Phillip McDonagh
- Boehringer Ingelheim Animal Health Australia, North Ryde, New South Wales 2113, Australia
| | - Louise Rae
- Boehringer Ingelheim Animal Health Australia, North Ryde, New South Wales 2113, Australia
| | - Lara Marwedel
- Boehringer Ingelheim Animal Health Australia, North Ryde, New South Wales 2113, Australia
| | | | - Vito Colella
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC3052, Australia
| | - Rebecca J Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, VIC3052, Australia
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18
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Kamdem CN, Tiofack AAZ, Mewamba EM, Tchounkeu EY, Tatang JRA, Mengoue ELT, Mbagnia CMT, Fogue PS, Womeni HM, Simo G. Fine mapping of Ascaris lumbricoides, Trichuris trichiura and hookworm infections in sub-districts of Makenene in Centre Region of Cameroun. Sci Rep 2022; 12:13935. [PMID: 35978014 PMCID: PMC9385646 DOI: 10.1038/s41598-022-18285-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 08/09/2022] [Indexed: 11/20/2022] Open
Abstract
Preventive chemotherapy (PC) that remains the main control strategy recommended by the World Health Organization to achieve the elimination of soil-transmitted helminth (STH) infections as a public health problem must be strengthened by identifying the remaining transmission hot-spots for the deployment of appropriate control measures. This study was designed to assess the prevalence and infections intensities of soil-transmitted helminths and perform micro scale mapping in order to identify transmission hot-spots for targeted control operations. Stool samples were collected from 1775 children in ten primary schools of eight sub-districts of Makenene in Cameroon. Kato Katz technique was used to process and examine stool samples to detect the eggs of soil-transmitted nematodes. The prevalence of soil-transmitted helminth species as well as the infection intensities was compared. Data visualizations in forms of maps were made using Quantum geographic information system (QGIS) software. The overall prevalence of soil-transmitted helminth infections was 4.8% with a 95% confidence interval (CI) of 3.8–5.9%: 3.0% (95% CI 2.2–3.9) for Ascaris lumbricoides, 1.4% (95% CI 0.9–2.0) for Trichuris trichiura and 0.8% (95% CI 0.5–1.4) for hookworms. The prevalence of soil-transmitted helminth species differ significantly between schools and sub-districts. The intensity of infections was light (2.4%, 1.1% and 0.8%), moderate (0.4%, 0.1% and 0.1%) and heavy (0.2%, 0.2% and 0%) for A. lumbricoides, T. trichiura and hookworm respectively. The mean intensity of infections was 7255 EPG for A. lumbricoides, 2900 EPG for T. trichiura and 298 EPG for hookworm. Between schools, significant difference was recorded in the means of infection intensities of T. Trichiura and hookworms but not for A. lumbricoides. This difference was also significant for T. Trichiura when comparison were between sex. No significant difference were recorded when the comparison were between age. Fine mapping revealed that children harbouring heavy infections were clustered in the same sub-districts; highlighting the presence of high endemicity sub-districts and hot-spots for the transmission of different soil-transmitted helminth species. This study showed a diversity in the prevalence and transmission of different soil-transmitted helminth species. It also hightlighted the need for micro scale mapping to enable the localisation of high endemicity sub-districts and transmission hot-spot sites where targeted control operations must be deployed to achieve STH elimination.
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Affiliation(s)
- Cyrille Nguemnang Kamdem
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Auvaker Arnol Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Estelle Mezajou Mewamba
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Esthelline Yangea Tchounkeu
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Joël Rostand Atiokeng Tatang
- Research Unit of Biology and Applied Ecology, Department of Animal Biology, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Edmond Loic Tekeu Mengoue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Carole Mureille Tchami Mbagnia
- Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon
| | - Pythagore Soubgwi Fogue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon
| | - Hilaire Macaire Womeni
- "Unité de Recherche de Biochimie, des plantes Médicinales, des Sciences Alimentaires et Nutrition", University of Dschang, Dschang, Cameroon
| | - Gustave Simo
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO Box 67, Dschang, Cameroon.
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19
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Preliminary evaluation of different methods to detect and quantify Taenia eggs in sludge and water samples: A spiking experiment to assess recovery efficiency. Food Waterborne Parasitol 2022; 28:e00170. [PMID: 35844813 PMCID: PMC9283506 DOI: 10.1016/j.fawpar.2022.e00170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 06/22/2022] [Accepted: 07/01/2022] [Indexed: 11/23/2022] Open
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20
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Curico G, García-Bardales P, Pinedo T, Shapiama W, Moncada-Yaicate M, Romaina L, Yori PP, Paredes-Olortegui M, Meza-Sánchez G, Lescano AG, Paz-Soldan VA, Schiaffino F, Oberhelman RA, Kosek MN. Resistance to single dose albendazole and reinfection with intestinal helminths among children ages 2 to 11 years from the Peruvian Amazon region: a study protocol. BMC Infect Dis 2022; 22:528. [PMID: 35672751 PMCID: PMC9171935 DOI: 10.1186/s12879-022-07494-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 05/25/2022] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Deworming programs aimed at reducing morbidity and mortality from geohelminth infections are common in many countries where these infections are endemic, but data demonstrating increasing levels of resistance to albendazole and mebendazole are causes for concern. Studies to evaluate the clinical efficacy of deworming programs are critical to maintain high infection control goals. METHODS We propose to assess the clinical efficacy of Peruvian national guidelines for deworming programs in a prospective observational study conducted in the Amazon River basin area near Iquitos, Peru. Major outcomes to be evaluated include (1) albendazole resistance of intestinal helminths (trichuriasis, ascariasis, hookworm), and (2) frequency of reinfection with intestinal helminths 4 months after treatment with albendazole. Children ages 2-11 years from the Belén District of Iquitos will be identified based on a community census. Following parental informed consent, demographic data, weight, and height will be recorded and a stool specimen for parasitological exam by direct observation and Kato-Katz concentration method, and helminthic egg counts will be collected prior to administration of albendazole, following Peruvian national guidelines. Follow-up stool specimens examined in the same manner will be collected at 20 days, 90 days, and 100 days following initial administration of albendazole, and based on parasites found repeat treatment will be administered in accordance with national guidelines. Real-time multiplex qPCR will be performed on helminth positive samples collected prior to initial deworming and on helminth-positive specimens detected on day 15-20. A total sample size of 380 participants was calculated based on total population in the target group and prevalence estimates of helminth infections and clinical resistance based on recent data. DISCUSSION Data from observational clinical efficacy studies are important to guide geohelminth infection control programs. Trial registration https://www.researchregistry.com/ . Identification number: researchregistry7736; Registered retrospectively March 13, 2022; https://www.researchregistry.com/browse-the-registry#home/registrationdetails/622e024cf06132001e3327bf/.
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Affiliation(s)
- Greisi Curico
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Paul García-Bardales
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Tackeshy Pinedo
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Wagner Shapiama
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Miguel Moncada-Yaicate
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Lucero Romaina
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Pablo P. Yori
- grid.27755.320000 0000 9136 933XDivision of Infectious Diseases and International Health, Department of Internal Medicine, University of Virginia, MR-6 Rm 2207, 345 Crispell Dr, Charlottesville, VA 22908 USA
| | - Maribel Paredes-Olortegui
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Graciela Meza-Sánchez
- grid.440594.80000 0000 8866 0281Universidad Nacional de la Amazonia Peruana, Jirón Nauta, 16002 Iquitos, Peru
| | - Andrés G. Lescano
- grid.11100.310000 0001 0673 9488Facultad de Salud Pública y Administración, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado, 430. San Martin de Porres, Lima, Peru
| | - Valerie A. Paz-Soldan
- grid.265219.b0000 0001 2217 8588Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2310, New Orleans, LA 70112 USA
| | - Francesca Schiaffino
- Laboratorio Satelite Iquitos, Asociación Benéfica Prisma, Área de Investigaciones Biomédicas, Calle Ramirez Hurtado Nº 622, Iquitos, Peru
| | - Richard A. Oberhelman
- grid.265219.b0000 0001 2217 8588Department of Tropical Medicine, Tulane School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2310, New Orleans, LA 70112 USA
| | - Margaret N. Kosek
- grid.27755.320000 0000 9136 933XDivision of Infectious Diseases and International Health, Department of Internal Medicine, University of Virginia, MR-6 Rm 2207, 345 Crispell Dr, Charlottesville, VA 22908 USA
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Using quantitative PCR to identify opportunities to strengthen soil-transmitted helminth control in Solomon Islands: A cross-sectional epidemiological survey. PLoS Negl Trop Dis 2022; 16:e0010350. [PMID: 35604904 PMCID: PMC9126411 DOI: 10.1371/journal.pntd.0010350] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/22/2022] [Indexed: 11/19/2022] Open
Abstract
Background The Kato-Katz microscopy technique is the global standard for assessment of soil-transmitted helminth (STH) burden. However, major limitations include its poor sensitivity, requirement for rapid sample processing, and inability to differentiate hookworm species nor detect Strongyloides spp. infections. We assessed the prevalence and intensity of STH species in Solomon Islands by conducting a province-wide survey using quantitative PCR (qPCR) for diagnosis, which can provide much better characterisation of STH burden than microscopy. Methodology/Principal findings We conducted a cross-sectional survey in 18 villages in Western Province to detect infections with six STH species and quantify intensity with three. We used linear mixed model regression to identify potential water, sanitation, and hygiene (WASH) and environmental risk factors for infection. We collected stool specimens from 830 village residents. Overall STH prevalence was 63.3% (range 27.5 to 91.5% across villages), led by Necator americanus (54.5% [range 17.5–89.4%]), followed by Ancylostoma ceylanicum (15.5% [range 2.8–45.8%]), Trichuris trichiura (9.1% [range 0–79.2%]), and Strongyloides spp. (3.2% [range 0–29.2%]). Most infections were of light intensity for N. americanus (85.7%) and T. trichiura (90.7%). Owning a household latrine was associated with a lower risk of N. americanus infection (AOR 0.41, 95% CI 0.24–0.68) while greater precipitation was linked to more common T. trichiura infection (AOR 1.14, 95% CI 1.04–1.25). Conclusion/Significance In this first large-scale population survey of STH in the Pacific using qPCR, we found evidence that ivermectin should be incorporated into STH control programmes because of the presence of T. trichiura and Strongyloides spp., both of which are poorly responsive to albendazole. Furthermore, One Health strategies are needed for improved A. ceylanicum and Strongyloides spp. control, WASH access and use should be improved to complement deworming programmes, and control efforts should ideally be expanded to entire communities. Trial registration ClinicalTrials.gov Australian and New Zealand Clinical Trials Registry ACTRN12618001086257. Routine assessments of the burden of intestinal worm infections rely on microscopy-based diagnostic methods, such as the Kato-Katz technique. However major limitations include its poor sensitivity, requirement for rapid sample processing, and inability to differentiate individual hookworm species and detect Strongyloides spp. infections. It is important to assess the burden of each of these infections to design control approaches beyond the current core strategy of albendazole preventive chemotherapy. Use of qPCR for diagnosis could address these gaps because it can distinguish all relevant intestinal worm species. We completed a province-wide intestinal worm infections prevalence survey using qPCR in Western Province, Solomon Islands. Overall prevalence was extremely high (62.5%). We identified a high burden of Necator americanus (54.5%) and detected Ancylostoma ceylanicum (15.5%), Trichuris trichiura (9.1%), and Strongyloides spp. (3.2%) infections. Increased age and precipitation were associated with higher prevalence of infection, while owning a household latrine was associated with lower odds of N. americanus infection. Our findings support the need to incorporate ivermectin into deworming programmes for Strongyloides spp. and T. trichiura control as these species are poorly responsive to albendazole, implement One Health strategies to address the zoonotic A. ceylanicum and Strongyloides spp., and expand control efforts to reach entire communities. WASH access should also be improved to complement deworming programmes.
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Traub RJ, Zendejas-Heredia PA, Massetti L, Colella V. Zoonotic hookworms of dogs and cats - lessons from the past to inform current knowledge and future directions of research. Int J Parasitol 2021; 51:1233-1241. [PMID: 34748782 DOI: 10.1016/j.ijpara.2021.10.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/24/2021] [Accepted: 10/26/2021] [Indexed: 01/17/2023]
Abstract
The early-to-mid 1900s was an era that marked the first published reports of clinical cases and experimental human infections that provided valuable evidence to inform our current knowledge on the zoonotic nature of the canid and felid hookworms. To this day, descriptions of the pathognomonic syndromes produced in humans by these early pioneers provide vital information on the putative geographical distribution of these hookworm species, even before their discovery in dogs and cats. Cases of hookworm-related cutaneous larvae migrans and Ancylostoma caninum-induced eosinophilic enteritis continue to be reported in the medical literature, most commonly in recent migrants or returned travellers who have spent time in regions in which these canine and feline hookworms remain highly endemic. Ancylostoma ceylanicum, now recognised as the second most common hookworm infecting humans in the Asia Pacific region, is also being reported in regions of Africa and South America previously assumed free of this parasite. Despite the substantial technological progress made in the field of parasite diagnostics, our knowledge on the epidemiology and population-level morbidity impacts of these zoonotic hookworms in humans has remained relatively stagnant over the last few decades, with 'covert' infections continuing to remain undetected by currently available forms of routine diagnostics. Improved diagnostic tools that enable accurate and rapid species-specific diagnosis of zoonotic hookworm infections in humans are required to provide the necessary evidence to advocate for future investments in One Health-based intervention strategies.
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Affiliation(s)
- Rebecca J Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville 3052, Victoria, Australia.
| | - Patsy A Zendejas-Heredia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Luca Massetti
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Vito Colella
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville 3052, Victoria, Australia
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Colella V, Khieu V, Worsley A, Senevirathna D, Muth S, Huy R, Odermatt P, Traub RJ. Risk profiling and efficacy of albendazole against the hookworms Necator americanus and Ancylostoma ceylanicum in Cambodia to support control programs in Southeast Asia and the Western Pacific. THE LANCET REGIONAL HEALTH. WESTERN PACIFIC 2021; 16:100258. [PMID: 34590062 PMCID: PMC8403762 DOI: 10.1016/j.lanwpc.2021.100258] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 07/17/2021] [Accepted: 07/26/2021] [Indexed: 11/18/2022]
Abstract
Background: Hookworm disease is endemic throughout many parts of the Asia Pacific, despite targeted control programs of at-risk populations. The success of these programs has been hindered by the limited efficacy of widely-used mebendazole, rapid re-infection rates linked to persistent reservoirs of untreated people and dogs, and the low sensitivity of conventional coprodiagnostic techniques employed. Methods: Here, we used standard faecal flotation (SFF) and a multiplex qPCR (mqPCR) assay to calculate and compare species-specific cure and egg reduction rates of single dose albendazole (400 mg) against hookworm infections at community level. Data from a cross-sectional survey in 1,232 people from Cambodia were used to inform a generalised linear mixed model to identify risk factors linked to hookworm infection(s) at baseline. Furthermore, we calculated risk factors associated to the probability of being cured after albendazole administration. Findings: Overall, 13·5% of all 1,232 people tested by SFF were positive for hookworm infection(s). Most (80·1%) infected people were >12 years of age, hence above the age targeted by the WHO control program. We estimate that as age increases, the odds of being infected increases at a faster rate for females than for males. We revealed a substantial difference in cure rate of hookworm infection(s) following albendazole treatment using the SFF (81·5%) and mqPCR (46·4%) assays, and provide the first data on the efficacy of this drug against the zoonotic hookworm Ancylostoma ceylanicum. We estimated that as age increases by one year, the odds of being cured decreases by 0·4%-3·7%. Similarly, the odds of being cured for people who boiled drinking water was estimated to be between 1·02 and 6·82. Interpretation: These findings show that the adoption of refined diagnostic techniques is central to monitoring hookworm infection(s) and the success of control strategies, which can ultimately aid in reducing associated morbidity in human populations. The approach taken is likely to be directly applicable to other parts of Southeast Asia and the Western Pacific, where specific epidemiological conditions might hamper the success of targeted treatment programs. Funding: Faculty of Veterinary and Agricultural Sciences Strategic Research Funds, The University of Melbourne.
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Affiliation(s)
- Vito Colella
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Australia
| | - Virak Khieu
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | | | - Dammika Senevirathna
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Australia
| | - Sinuon Muth
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Rekol Huy
- National Centre for Parasitology, Entomology and Malaria Control, Ministry of Health, Phnom Penh, Cambodia
| | - Peter Odermatt
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Rebecca J. Traub
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Australia
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Detection of six soil-transmitted helminths in human stool by qPCR- a systematic workflow. PLoS One 2021; 16:e0258039. [PMID: 34591904 PMCID: PMC8483301 DOI: 10.1371/journal.pone.0258039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 09/16/2021] [Indexed: 11/19/2022] Open
Abstract
Soil-transmitted helminths (STH) infect up to one-quarter of the global population, with a significant associated disease burden. The main human STH are: Ancylostoma spp. and Necator americanus (hookworms); Ascaris lumbricoides, Trichuris trichiura, and Strongyloides stercoralis. The aim of this study was to establish a scalable system for stool STH multiplex quantitative real-time polymerase chain reactions (qPCR). Stool samples collected in Fiji and preserved in potassium dichromate were transferred to Melbourne at ambient temperature. Samples were washed to remove potassium dichromate and DNA was extracted with the Mini-Beadbeater-24 and a column-based kit. A SYBR green qPCR to detect the vertebrate mitochondrial gene was used as a DNA extraction control. Samples were tested using a probe-based multiplex qPCR targeting A. lumbricoides, T. trichiura and S. stercoralis, and in a second multiplex reaction to detect hookworms to the species level (A. duodenale, A. ceylanicum, N. americanus). An internal amplification control in both multiplex assays was included to prevent false-negative results due to PCR inhibitors. Samples were homogenised for a single cycle of 40 seconds to release STH DNA and washed stool was stored for up to 15 weeks at -30°C without compromising DNA. Our multiplex qPCR detected multiple species of STH without reduced sensitivity compared to singleplex. qPCR data from 40 stools was validated against STH-positive stools determined by microscopy. We have developed and validated an efficient and staged system for detecting six clinically important STH affecting humans that could be easily implemented without advanced automation in any qPCR-capable laboratory.
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Colella V, Bradbury R, Traub R. Ancylostoma ceylanicum. Trends Parasitol 2021; 37:844-845. [PMID: 34049804 DOI: 10.1016/j.pt.2021.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Vito Colella
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia.
| | - Richard Bradbury
- School of Health and Life Sciences, Federation University Australia, Berwick, Victoria, Australia
| | - Rebecca Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
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