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Zainol DA, Anuar NS, Abdul Halim NSS, Kaur M, Noordin R, Rahumatullah A. Systematic Review of Strongyloides stercoralis Infection Diagnosis in Southeast Asia: Insights from Parasitological, Molecular, and Serological Approaches. Am J Trop Med Hyg 2024; 111:724-735. [PMID: 39137756 PMCID: PMC11448514 DOI: 10.4269/ajtmh.23-0599] [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: 09/08/2023] [Accepted: 05/13/2024] [Indexed: 08/15/2024] Open
Abstract
Accurate diagnosis of strongyloidiasis is crucial for effective treatment and prevention of complications. We reviewed the current landscape of diagnostic assays used in detecting Strongyloides infection in Southeast Asia. A literature search was performed using Scopus, PubMed, and Web of Science databases spanning the last three decades. Based on the exclusion and inclusion criteria, 52 papers were included in this review. We outlined the diagnostic methods used and their advantages and drawbacks. Insensitive parasitological methods were commonly used, thus underscoring the underestimation of Strongyloides infection rates in Southeast Asia. A combination of diagnostic methods (i.e., microscopy, molecular techniques, and serology) is preferred because it leads to more effective detection and higher prevalence rates. New approaches have been developed, including urine ELISAs and rapid lateral flow tests. Improving and standardizing diagnostics and making them more accessible can improve Strongyloides prevalence estimates and facilitate control efforts.
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Affiliation(s)
- Dinie Adila Zainol
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Penang, Malaysia
| | - Nor Suhada Anuar
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Penang, Malaysia
| | - Nur Shuhaidatul Sarmiza Abdul Halim
- Neurorehabilitation Engineering and Assistance Systems Research (NEAR), School of Mechanical Engineering, Engineering Campus, Universiti Sains Malaysia (USM), Penang, Malaysia
| | - Mansheender Kaur
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Penang, Malaysia
| | - Rahmah Noordin
- Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Anizah Rahumatullah
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia (USM), Penang, Malaysia
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Garg P, Bhasin SL, Malhotra P, Rana SS, Singh S, Sethi J, Sehgal R, Khurana S, Datta P. Multiplex PCR for gastrointestinal parasites in stool: Benchmarking against direct microscopy and simplex PCR. Diagn Microbiol Infect Dis 2024; 110:116475. [PMID: 39096665 DOI: 10.1016/j.diagmicrobio.2024.116475] [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] [Received: 05/22/2024] [Revised: 06/29/2024] [Accepted: 07/29/2024] [Indexed: 08/05/2024]
Abstract
PURPOSE To develop and validate a multiplex conventional PCR assay to simultaneously detect Cryptosporidium spp., Entamoeba histolytica, and Giardia lamblia in diarrheal samples as a rapid, cost-effective, and sensitive diagnostic tool for prevalent co-infections for improved diagnostic accuracy and efficiency in resource-limited settings. METHODS Stool samples collected from patients with gastrointestinal symptoms after taking written consent, processed via wet mount, iodine mount, and PCR assays. Cohen's kappa statistical analysis was done to test agreement. RESULT Among 240 patients, 28.75% showed intestinal protozoa via Microscopy; Single-plex and multiplex PCR demonstrated 100% concordance, detecting 27.9%; confirmed by sequencing. Highest parasite positivity was observed in transplant and immunocompromised patients, with moderate to almost perfect agreement between microscopy and molecular methods. CONCLUSION Multiplex-conventional PCR offers superior sensitivity and specificity over microscopy and 100% concordance with single-plex PCR, enabling rapid, cost-effective diagnosis of multiple parasites from single stool sample. Its adoption could revolutionize parasitic infection management in routine diagnostics.
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Affiliation(s)
- Puja Garg
- Department of Medical Parasitology PGIMER, Chandigarh, 160012, India
| | - Sadhna Lal Bhasin
- Department of Paediatrics Gastroenterology PGIMER, Chandigarh, 160012, India
| | - Pankaj Malhotra
- Department of Clinical Haematology and Oncology PGIMER, Chandigarh, 160012, India
| | | | - Shreya Singh
- Department of Microbiology Dr. BR Ambedkar State Institute of Medical Sciences, Mohali, Punjab, 160062, India
| | - Jasmine Sethi
- Department of Medical Parasitology PGIMER, Chandigarh, 160012, India
| | - Rakesh Sehgal
- Department of Microbiology Aarupudai Veedu Medical College & Hospital, VMRF-DU, Puducherry, 607403, India
| | - Sumeeta Khurana
- Department of Medical Parasitology PGIMER, Chandigarh, 160012, India
| | - Priya Datta
- Department of Medical Parasitology PGIMER, Chandigarh, 160012, India.
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Coppens J, Drieghe C, Potters I, Schwob JM, Van Esbroeck M. Evaluation of the Allplex GI Parasite and Helminth PCR Assay in a Belgian Travel Clinic. Diagnostics (Basel) 2024; 14:1998. [PMID: 39335677 PMCID: PMC11430856 DOI: 10.3390/diagnostics14181998] [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: 07/17/2024] [Revised: 08/22/2024] [Accepted: 09/05/2024] [Indexed: 09/30/2024] Open
Abstract
Recently a number of broad-range stool parasite PCR assays have been developed. However, there is ongoing disagreement regarding their diagnostic performance, as various studies have produced contradictory results. In this study, we compared the diagnostic accuracy of the Seegene Allplex GI-Parasite and Allplex GI-Helminth assays (SA) with the conventional methods used at the travel clinic of the Institute of Tropical Medicine (ITM) including microscopy, antigen testing, and molecular detection in order to provide insights into the strengths and limitations of this diagnostic tool which may be crucial to select the most appropriate diagnostic tools for the suspected pathogen. A total of 97 native stool samples from 95 patients with suspected gastrointestinal illness were analyzed, including 26 from a frozen collection and 71 prospectively collected samples. The diagnostic performance of SA was notably superior to the conventional workflow in detecting Dientamoeba fragilis (sensitivity 100% vs. 47.4%) and Blastocystis hominis (sensitivity 95% vs. 77.5%). SA had a comparable performance with the conventional workflow in detecting pathogenic protozoa (sensitivity 90% vs. 95%). In contrast, SA had a much lower diagnostic performance in detecting helminths (59.1%) compared to the conventional workflow (100%). We conclude that the Seegene Allplex GI-Parasite assay may be useful for protozoa screening in low-endemic industrialized countries. However, the Allplex GI-Helminth assay is not recommended due to its suboptimal performance compared to microscopy.
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Affiliation(s)
- Jasmine Coppens
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Charlotte Drieghe
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Idzi Potters
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | - Jean-Marc Schwob
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
- Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, 1205 Geneva, Switzerland
- Bacteriology and Parasitology Laboratory, Geneva University Hospitals, 1205 Geneva, Switzerland
| | - Marjan Van Esbroeck
- Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
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Schutte AHJ, Koelewijn R, Ajjampur SSR, Levecke B, McCarthy JS, Mejia R, Williams SA, Verweij JJ, van Lieshout L, van Hellemond JJ. Detection of soil-transmitted helminths and Schistosoma spp. by nucleic acid amplification test: Results of the first 5 years of the only international external quality assessment scheme. PLoS Negl Trop Dis 2024; 18:e0012404. [PMID: 39116195 PMCID: PMC11335160 DOI: 10.1371/journal.pntd.0012404] [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: 03/18/2024] [Revised: 08/20/2024] [Accepted: 07/25/2024] [Indexed: 08/10/2024] Open
Abstract
BACKGROUND Infections with soil-transmitted helminths (STH) and schistosomiasis (SCH) result in a significant global health burden, particularly in rural communities in low and middle-income countries. While microscopy remains the primary diagnostic method for STH and SCH in resource-limited settings, nucleic acid amplification tests (NAATs) are gaining prominence as tools for evaluation of public health control programs in endemic countries, and individual diagnosis in high-income countries. Despite the high sensitivity and specificity of NAATs, previous research has highlighted inter-laboratory variations, both in technical and clinical performance, justifying the need for continuous proficiency testing. METHODOLOGY Results from 5 rounds over a 5-year period of the so far only longitudinal international Helminth External Molecular Quality Assessment Scheme (HEMQAS), coordinated by the Dutch Foundation for Quality Assessment in Medical Laboratories (SKML), were examined in order to (i) assess the diagnostic proficiency of laboratories in detecting helminths in stool and (ii) identify potential factors contributing to variations in performance. OUTCOME AND CONCLUSIONS Thirty-six laboratories, from 18 countries and 5 continents, participated in HEMQAS. The overall diagnostic performances were satisfying, with remarkably low numbers (<2%) of false-positive results. False-negative results were more often reported for stool (15%) than for DNA (5%) samples. False-negative results varied largely between targets (the highest number (29%) for Trichuris trichiura). Twenty-five laboratories provided a sufficient number of results for a robust comparison between participating laboratories, which confirmed substantial inter-laboratory variability in quantitative NAAT results (Cq-values). This variability likely arises from differences in pre-treatment, DNA isolation and DNA-target amplification procedures. This study emphasizes the complexity of molecular diagnosis for STH and SCH, highlighting the critical role of proper stool preparation and DNA isolation methods. The results underscore the necessity for laboratory professionals and public health decision-makers to recognize these complexities and continuously undertake external quality assessment schemes to ensure accurate and reliable performance in molecular diagnosis.
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Affiliation(s)
- Annemiek H. J. Schutte
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Rob Koelewijn
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Sitara S. R. Ajjampur
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Bruno Levecke
- Department of Translational Physiology, Infectiology and Public Health, Ghent University, Merelbeke, Belgium
| | - James S. McCarthy
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Australia
| | - Rojelio Mejia
- Department of Pediatrics–Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America
| | - 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
| | - Jaco J. Verweij
- Laboratory for Medical Microbiology and Immunology, Elisabeth-Tweesteden Hospital, Tilburg, the Netherlands
| | - Lisette van Lieshout
- Leiden University Center for Infectious Diseases (LU-CID); Parasitology group, Leiden University Medical Center, Leiden, The Netherlands
| | - Jaap J. van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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Scarso S, Rakotoarivelo RA, Hey JC, Rasamoelina T, Razafindrakoto AR, Rasolojaona ZT, Razafindralava NM, Remkes A, Rakotozandrindrainy N, Rasoamanamihaja CF, Schwarz NG, May J, Rakotozandrindrainy R, Marchese V, Formenti F, Perandin F, Tamarozzi F, Mazzi C, Fusco D, Buonfrate D. Prevalence of Strongyloides stercoralis and other helminths in four districts of Madagascar. Trop Med Health 2024; 52:49. [PMID: 39075624 PMCID: PMC11285119 DOI: 10.1186/s41182-024-00619-y] [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: 05/10/2024] [Accepted: 07/18/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND Estimation of prevalence of Strongyloides stercoralis infection is required in endemic areas, in order to identify areas in need of control programmes. Data on prevalence of strongyloidiasis in Madagascar are scant. Aim of this work was to estimate prevalence of S. stercoralis in four districts of Madagascar. METHODS Fecal and serum samples collected in the context of a previous study on schistosomiasis were tested with S. stercoralis real-time PCR and serology, respectively. A multiplex real-time PCR for Ascaris lumbricoides, Ancylostoma duodenalis, Necator americanus, and Trichuris trichiura was done on fecal samples collected in the areas demonstrating higher prevalence of strongyloidiasis. Comparisons between proportions were made using Fisher exact test, with false discovery rate correction used for post-hoc comparisons. A multivariable Firth logistic regression model was used to assess potential risk factors for S. stercoralis infection. RESULTS Overall, 1775 serum samples were tested, of which 102 of 487 (20.9%) and 104 of 296 (35.2%) were serological-positive in Marovoay and in Vatomandry districts (both coastal areas), respectively, compared to 28 of 496 (5.6%) and 30 of 496 (6.1%) in Tsiroanomandidy and in Ambositra districts (both highlands), respectively (adj. p < 0.001). PCR for S. stercoralis was positive in 15 of 210 (7.1%) and in 11 of 296 (3.7%) samples from Marovoay from Vatomandry, respectively, while was negative for all samples tested in the other two districts. High prevalence of A. lumbricoides (45.9%), hookworm (44.6%) and T. trichiura (32.1%) was found in Vatomandry. In the multivariable analysis, strongyloidiasis was associated with hookworm infection. Hookworm infection was also associated with male sex and lower education level. CONCLUSIONS S. stercoralis prevalence proved higher in coastal areas compared to highlands. Different climatic conditions may explain this distribution, along with previous rounds of anthelminthics distributed in the country, which may have reduced the parasite load in the population. The high prevalence of the other soil-transmitted helminths (STH) in Vatomandry was unexpected, given the good coverage with benzimidazole in control campaigns. Further studies are needed to explore the risk factors for STH and S. stercoralis infections in Madagascar, in order to align with the WHO recommendations.
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Affiliation(s)
- Salvatore Scarso
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | | | - Jana Christina Hey
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | | | | | | | - Aaron Remkes
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | | | - Norbert Georg Schwarz
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
| | - Jürgen May
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | - Valentina Marchese
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Fabio Formenti
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Francesca Perandin
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Francesca Tamarozzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Cristina Mazzi
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy
| | - Daniela Fusco
- Department of Infectious Diseases Epidemiology, Bernard Nocht Institute, Hamburg, Germany
- German Centre for Infection Research (DZIF), Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Dora Buonfrate
- Department of Infectious Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar di Valpolicella, Verona, Italy.
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Kocabiyik O, Amlashi P, Vo AL, Suh H, Rodriguez-Aponte SA, Dalvie NC, Love JC, Andrabi R, Irvine DJ. Vaccine targeting to mucosal lymphoid tissues promotes humoral immunity in the gastrointestinal tract. SCIENCE ADVANCES 2024; 10:eadn7786. [PMID: 38809992 PMCID: PMC11135404 DOI: 10.1126/sciadv.adn7786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/23/2024] [Indexed: 05/31/2024]
Abstract
Viruses, bacteria, and parasites frequently cause infections in the gastrointestinal tract, but traditional vaccination strategies typically elicit little or no mucosal antibody responses. Here, we report a strategy to effectively concentrate immunogens and adjuvants in gut-draining lymph nodes (LNs) to induce gut-associated mucosal immunity. We prepared nanoemulsions (NEs) based on biodegradable oils commonly used as vaccine adjuvants, which encapsulated a potent Toll-like receptor agonist and displayed antigen conjugated to their surface. Following intraperitoneal administration, these NEs accumulated in gut-draining mesenteric LNs, priming strong germinal center responses and promoting B cell class switching to immunoglobulin A (IgA). Optimized NEs elicited 10- to 1000-fold higher antigen-specific IgG and IgA titers in the serum and feces, respectively, compared to free antigen mixed with NE, and strong neutralizing antibody titers against severe acute respiratory syndrome coronavirus 2. Thus, robust gut humoral immunity can be elicited by exploiting the unique lymphatic collection pathways of the gut with a lymph-targeting vaccine formulation.
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Affiliation(s)
- Ozgun Kocabiyik
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Parastoo Amlashi
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - A. Lina Vo
- Consortium for HIV/AIDS Vaccine Development (CHAVD), Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Heikyung Suh
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sergio A. Rodriguez-Aponte
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Neil C. Dalvie
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - J. Christopher Love
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139, USA
| | - Raiees Andrabi
- Consortium for HIV/AIDS Vaccine Development (CHAVD), Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Darrell J. Irvine
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Consortium for HIV/AIDS Vaccine Development (CHAVD), Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard University, Cambridge, MA 02139, USA
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815 USA
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Gaidhane S, Gaidhane A, Khatib MN, Telrandhe S, Patil M, Saxena D, Bhardwaj P, Choudhari S, Zahiruddin QS. Estimation of the Parasitic Burden of Soil-Transmitted Helminths Among Pregnant Women in the Maharashtra State of India Using qPCR: A Community-Based Study. Indian J Community Med 2024; 49:157-164. [PMID: 38425985 PMCID: PMC10900441 DOI: 10.4103/ijcm.ijcm_249_23] [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: 04/19/2023] [Accepted: 11/01/2023] [Indexed: 03/02/2024] Open
Abstract
Background Soil-transmitted helminth (STH) infections are widespread in developing countries with inadequate sanitation facilities. These infections can lead to malnutrition, anemia, and other complications that can negatively impact both the mother's and fetus's health during pregnancy. This study aimed to estimate the burden of STH by Kato-Katz microscopy and quantitative polymerase chain reaction (qPCR) in pregnant women from rural India. The diagnostic accuracy of these two methods was also compared. Material and Methods A community-based cross-sectional study was conducted in rural areas of Wardha district of Maharashtra state. We randomly selected and interviewed 688 pregnant women. A total of 534 (77.61%) participants gave stool samples. Two containers (60 mL) labeled with a unique identification number were given to pregnant women to collect stool samples for Kato-Katz microscopy and qPCR. Stool specimens were transported to an accredited lab and examined within 24 hours. Suitable examinations were conducted to compare sensitivity between two tests. Results The results are presented for 534 participants who gave stool samples. The prevalence of any STH by Kato-Katz stool microscopy was 6.55% (95%CI 4.46-12.19), and that by qPCR was 20.41 (95%CI 17.53-29.40). The sensitivity of Kato-Katz microscopy was 29.17% compared to sensitivity of 90.83% by qPCR (P = 0.001). Pregnant women with STH infection have a significantly lower weight gain during pregnancy, and the majority were either mild or moderate anemic compared to those without STH. Conclusion The study highlighted significant differences in prevalence of STH among pregnant women by Kato-Katz microscopy and qPCR. The sensitivity of qPCR for detecting STH was higher than that of Kato-Katz microscopy.
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Affiliation(s)
- Shilpa Gaidhane
- Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
| | - Abhay Gaidhane
- Centre of One Health, School of Epidemiology and Public Health, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
| | - Mahalaqua Nazli Khatib
- Global Evidence Synthesis Initiative, Division of Evidence Synthesis, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
| | - Shital Telrandhe
- Global Health Academy, Centre of Early Childhood Development - Stepping Stones Project, Wardha, Maharashtra, India
| | - Manoj Patil
- Global Health Consortium Public Health and Research, School of Epidemiology and Public Health, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
| | - Deepak Saxena
- i Health Consortium, Department of Epidemiology, Indian Institute of Public Health, Gandhinagar, Gujarat, India
| | - Pankaj Bhardwaj
- School of Public Health (SPH), Department of Community Medicine and Family Medicine, AIIMS, Jodhpur, Rajasthan, India
| | - Sonali Choudhari
- School of Epidemiology and Public Health, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
| | - Quazi S. Zahiruddin
- South Asia Infant Feeding Research Network (SAIFRN), School of Epidemiology and Public Health, Jawaharlal Nehru Medical College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India
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Rotejanaprasert C, Chuaicharoen P, Prada JM, Thantithaveewat T, Adisakwattana P, Pan-ngum W. Evaluation of Kato-Katz and multiplex quantitative polymerase chain reaction performance for clinical helminth infections in Thailand using a latent class analysis. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220281. [PMID: 37598708 PMCID: PMC10440171 DOI: 10.1098/rstb.2022.0281] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 05/27/2023] [Indexed: 08/22/2023] Open
Abstract
Using an appropriate diagnostic tool is essential to soil-transmitted helminth control and elimination efforts. Kato-Katz (KK) is the most commonly used diagnostic, but recently other tools, such as real-time quantitative polymerase chain reaction (multiplex qPCR), are starting to be employed more. Here, we evaluated the performance of these two diagnostic tools for five helminth species in Thailand. In the absence of a gold standard, diagnostic performance can be evaluated using latent class analysis. Our results suggest that in moderate to high prevalence settings above 2% multiplex qPCR could be more sensitive than KK, this was particularly apparent for Opisthorchis viverrini in the northeastern provinces. However, for low prevalence, both diagnostics suffered from low sensitivity. Specificity of both diagnostics was estimated to be high (above 70%) across all settings. For some specific helminth infection such as O. viverrini, multiplex qPCR is still a preferable choice of diagnostic test. KK performed equally well in detecting Ascaris lumbricoides and Taenia solium when the prevalence is moderate to high (above 2%). Neither test performed well when the prevalence of infection is low (below 2%), and certainly in the case for hookworm and Trichuris trichiura. Combination of two or more diagnostic tests can improve the performance although the cost would be high. Development of new methods for helminth surveillance at the pre-elimination phase is therefore very important. This article is part of the theme issue 'Challenges and opportunities in the fight against neglected tropical diseases: a decade from the London Declaration on NTDs'.
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Affiliation(s)
- Chawarat Rotejanaprasert
- Department of Tropical Hygiene, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
| | | | - Joaquin M. Prada
- Faculty of Health and Medical Sciences, School of Veterinary Medicine, University of Surrey, Guildford, UK
| | | | - Poom Adisakwattana
- Department of Helminthology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Wirichada Pan-ngum
- Department of Tropical Hygiene, Mahidol University, Bangkok, Thailand
- Mahidol-Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
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9
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Nguemnang Kamdem C, Soubgwi Fogue P, Zebaze Tiofack AA, Mezajou Mewamba E, Tekeu Mengoue LE, Womeni MH, Simo G. Assessment of the capacity of Whatman filter papers as support to store stools for the molecular diagnostic testing of soil-transmitted helminthiasis. J Microbiol Methods 2023; 213:106824. [PMID: 37717625 DOI: 10.1016/j.mimet.2023.106824] [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] [Received: 07/25/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 09/19/2023]
Abstract
Storage of stools for the detection of soil-transmitted helminths (STH) remains challenging for the molecular diagnostic testing of STH infections. This study aimed to overcome this challenge by assessing the capacity of Whatman filter papers to store stools for the molecular detection of STHs. Stool samples were collected from school-aged children of soil-transmitted helminthiasis endemic areas of Cameroon and then, analysed using Kato Katz technique. For this study, 128 and 40 stool samples respectively with and without STH eggs were analysed. From each sample, 10, 20, 40 and 80 mg of stool were weighted and spread on 6 grades of Whatman filter papers that were stored at room temperature from one to ten weeks. DNA was extracted from spread stool using CTAB based-method. The amount of stool to spread on filter papers and the grade of filter paper offering good storage were determined by amplifying specific DNA fragments of Ascaris lumbricoides. The capacity of filter papers to store stool samples for several weeks before the molecular detection of STH species was assessed by amplifying specific DNA fragments of different STHs. The amplification rates of A. lumbricoides were significantly higher (P < 0.0001) for 10 and 20 mg of stored stools. Stools spread on Whatman paper grade 2 yielded the highest amplification rate of 100% for A. lumbricoides, T. trichiura and hookworm. PCR revealed STH infections in all the 128 spread stools carrying STH eggs. It also revealed Necator americanus and Ancylostoma duodenale respectively in 10 and 13 of 15 spread stools contained hookworm eggs. PCR confirmed the co-infections of these hookworm species as well as that of A. lumbricoides and Trichuris trichiura in 7 spread stools. Out of 40 stools without STH eggs, PCR revealed that 5 (12.5%) and 9 (22.5%) had respectively A. lumbricoides and T. trichiura infections. The amplification rate of each STH species was 100% from one to 8 weeks and decreased to 86.7% after 10 weeks of storage. This study highlighted the capacity of filter papers to store stools for the molecular detection of STHs. Storing stools on these papers will enable to monitor and evaluate control programs and ensure post-elimination surveillance.
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Affiliation(s)
- Cyrille Nguemnang Kamdem
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Pythagore Soubgwi Fogue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Auvaker Arnol Zebaze Tiofack
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Estelle Mezajou Mewamba
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Loic Edmond Tekeu Mengoue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, Dschang, Cameroon
| | - Macaire Hilaire 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, Dschang, Cameroon.
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10
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Arcenillas-Hernández I, de Ybáñez MRR, Martínez-Carrasco C. What is the sensitivity and exactness of post-mortem diagnostic method for cardiopulmonary nematodes in wild carnivores? towards the gold standard. Vet Res Commun 2023; 47:1369-1378. [PMID: 36918466 PMCID: PMC10485123 DOI: 10.1007/s11259-023-10084-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 02/13/2023] [Indexed: 03/16/2023]
Abstract
Cardiopulmonary nematodes cause health and fitness disorders in wild and domestic carnivores. The red fox (Vulpes vulpes) participates in the spread of these shared parasites at the domestic-wildlife interface. This study aimed to evaluate the sensitivity of post-mortem diagnostic method for detecting lungworms in carnivores, and its exactness to estimate the parasite intensity of each nematode species. Cardiorespiratory system of fifty-one foxes were examined through three consecutively methodological steps: first, the tracheobronchial tree, pulmonary arteries and their branches were opened (OT); next, lung parenchyma was immersed in water and squeezed (WS); finally, the parenchyma was artificially digested in a pepsin and chlorhydric acid solution (AD). Eucoleus aerophilus, Angiostrongylus vasorum, Crenosoma vulpis and Metathelazia capsulata were identified. The number of recovered nematodes in each step were 454 (OT), 285 (WS) and 141 (AD). The use of OT and WS helped to improve parasite intensity results and decreased false negative cases. Accordingly, when OT and WS were used together, the sensitivity in the detection of parasitized foxes was 96.1%, while the exactness of parasite intensity was 84%. When AD was performed, although sensitivity does not rise, results were more exact, increasing the total number of detected parasites by 16%. Moreover, AD improved the sensitivity in the detection of A. vasorum and M. capsulata, as well as quantifying more exactly the parasite intensity (92.5% and 92.3% of exactness without AD, respectively). Our study provides valuable information that should be taken into account when planning epidemiological studies based on cardiopulmonary nematode detection in carnivores.
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Affiliation(s)
- Irene Arcenillas-Hernández
- Dpto. de Sanidad Animal, Facultad de Veterinaria, Campus de Excelencia Internacional "Campus Mare, Nostrum" Universidad de Murcia, Espinardo, Murcia, 30100, España
| | - M R Ruiz de Ybáñez
- Dpto. de Sanidad Animal, Facultad de Veterinaria, Campus de Excelencia Internacional "Campus Mare, Nostrum" Universidad de Murcia, Espinardo, Murcia, 30100, España.
| | - Carlos Martínez-Carrasco
- Dpto. de Sanidad Animal, Facultad de Veterinaria, Campus de Excelencia Internacional "Campus Mare, Nostrum" Universidad de Murcia, Espinardo, Murcia, 30100, España
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11
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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: 5] [Impact Index Per Article: 5.0] [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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12
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Wongstitwilairoong B, Anothaisintawee T, Ruamsap N, Lertsethtakarn P, Kietsiri P, Oransathid W, Oransathid W, Gonwong S, Silapong S, Suksawad U, Sornsakrin S, Bodhidatta L, Boudreaux DM, Livezey JR. Prevalence of Intestinal Parasitic Infections, Genotypes, and Drug Susceptibility of Giardia lamblia among Preschool and School-Aged Children: A Cross-Sectional Study in Thailand. Trop Med Infect Dis 2023; 8:394. [PMID: 37624332 PMCID: PMC10457730 DOI: 10.3390/tropicalmed8080394] [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: 05/01/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/26/2023] Open
Abstract
This study aimed to estimate the prevalence of intestinal parasitic infections in children and assess the drug susceptibility and genotypes/assemblages of Giardia lamblia in Thailand. This cross-sectional study was conducted among children aged 3-12 years in Sangkhlaburi District, Kanchanaburi Province, Thailand, between 25 September 2017 and 12 January 2018. Parasites were identified by stool microscopic examination, cultivation of intestinal parasitic protozoa, and enzyme-linked immunosorbent assay (ELISA). Drug susceptibility and genotype of G. lamblia were performed, respectively, by a resazurin assay and Triosephosphate Isomerase A and B genes using modified primers and probes. Among the 661 participants, 445 had an intestinal parasitic infection, resulting in a prevalence of 67.32% (95% CI: 63.60-70.89%). Blastocystis hominis was the most prevalent protozoa infection (49.32%; 95% CI: 45.44-53.22%), while Ascaris lumbricoides was the most prevalent helminth infection (0.91%; 95% CI: 0.33-1.97%). The prevalence of G. lamblia was 17.40%, with genotype B being the most common. According to our study, intestinal parasitic infections were commonly found in Thai children. G. lamblia was the most common pathogenic protozoa infection identified and exhibited less susceptibility to metronidazole compared to furazolidone and mebendazole.
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Affiliation(s)
| | - Thunyarat Anothaisintawee
- Department of Bacterial and Parasitic Diseases, US Army Medical Directorate of the Armed Forces Research Institute of Medical Sciences, Bangkok 10120, Thailand; (B.W.); (P.L.); (P.K.); (W.O.); (W.O.); (S.G.); (S.S.); (U.S.); (S.S.); (L.B.); (D.M.B.); (J.R.L.)
| | - Nattaya Ruamsap
- Department of Bacterial and Parasitic Diseases, US Army Medical Directorate of the Armed Forces Research Institute of Medical Sciences, Bangkok 10120, Thailand; (B.W.); (P.L.); (P.K.); (W.O.); (W.O.); (S.G.); (S.S.); (U.S.); (S.S.); (L.B.); (D.M.B.); (J.R.L.)
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13
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Hutchins H, Bradley J, Pretorius E, Teixeira da Silva E, Vasileva H, Jones RT, Ndiath MO, Dit Massire Soumare H, Mabey D, Nante EJ, Martins C, Logan JG, Slater H, Drakeley C, D'Alessandro U, Rodrigues A, Last AR. Protocol for a cluster randomised placebo-controlled trial of adjunctive ivermectin mass drug administration for malaria control on the Bijagós Archipelago of Guinea-Bissau: the MATAMAL trial. BMJ Open 2023; 13:e072347. [PMID: 37419638 PMCID: PMC10335573 DOI: 10.1136/bmjopen-2023-072347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
INTRODUCTION As malaria declines, innovative tools are required to further reduce transmission and achieve elimination. Mass drug administration (MDA) of artemisinin-based combination therapy (ACT) is capable of reducing malaria transmission where coverage of control interventions is already high, though the impact is short-lived. Combining ACT with ivermectin, an oral endectocide shown to reduce vector survival, may increase its impact, while also treating ivermectin-sensitive co-endemic diseases and minimising the potential impact of ACT resistance in this context. METHODS AND ANALYSIS MATAMAL is a cluster-randomised placebo-controlled trial. The trial is being conducted in 24 clusters on the Bijagós Archipelago, Guinea-Bissau, where the peak prevalence of Plasmodium falciparum (Pf) parasitaemia is approximately 15%. Clusters have been randomly allocated to receive MDA with dihydroartemisinin-piperaquine and either ivermectin or placebo. The primary objective is to determine whether the addition of ivermectin MDA is more effective than dihydroartemisinin-piperaquine MDA alone in reducing the prevalence of P. falciparum parasitaemia, measured during peak transmission season after 2 years of seasonal MDA. Secondary objectives include assessing prevalence after 1 year of MDA; malaria incidence monitored through active and passive surveillance; age-adjusted prevalence of serological markers indicating exposure to P. falciparum and anopheline mosquitoes; vector parous rates, species composition, population density and sporozoite rates; prevalence of vector pyrethroid resistance; prevalence of artemisinin resistance in P. falciparum using genomic markers; ivermectin's impact on co-endemic diseases; coverage estimates; and the safety of combined MDA. ETHICS AND DISSEMINATION The trial has been approved by the London School of Hygiene and Tropical Medicine's Ethics Committee (UK) (19156) and the Comite Nacional de Eticas de Saude (Guinea-Bissau) (084/CNES/INASA/2020). Results will be disseminated in peer-reviewed publications and in discussion with the Bissau-Guinean Ministry of Public Health and participating communities. TRIAL REGISTRATION NUMBER NCT04844905.
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Affiliation(s)
- Harry Hutchins
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - John Bradley
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Elizabeth Pretorius
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Eunice Teixeira da Silva
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Hristina Vasileva
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert T Jones
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - David Mabey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Ernesto Jose Nante
- Programa Nacional de Luta Contra o Paludismo, Ministério de Saúde, Bissau, Guinea-Bissau
| | | | - James G Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation, London, UK
| | | | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amabelia Rodrigues
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Anna R Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
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14
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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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15
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El-Wakil ES, Zalat RS, El-Badry AA. Mapping gut parasitism patterns in a cohort of Egyptians. Sci Rep 2023; 13:9961. [PMID: 37340037 DOI: 10.1038/s41598-023-36320-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/01/2023] [Indexed: 06/22/2023] Open
Abstract
In developing countries, the prevalence of intestinal parasitic infection is still significant, particularly due to geographical and socioeconomic variables. The objective of this study was to map the distribution pattern of intestinal parasitic infection in a cohort of the Egyptian population, as well as to assess associated risk factors. A cross-sectional hospital-based study was conducted on 386 patients. A single fecal specimen was collected from the study individual and examined microscopically for the detection of parasitic infection. DNA was extracted from all samples and utilized to amplify Entamoeba histolytica complex species, Cryptosporidium species, Giardia intestinalis assemblages, and Blastocystis species using PCRs. Typing of Cryptosporidium species and Giardia intestinalis assemblages was performed using restriction enzymes RasI and HaeIII respectively. While Blastocystis spp. subtypes (ST) were identified through sequencing of PCR products and phylogenetic analysis. 59.6% (230/386) of the study patients were infected with one or more intestinal parasites, 87.4%; 201/230 of patients had mono-parasitic infections, and 12.6%; 29/230 had multiple-parasitic infections (P < 0.0001). The predominant protozoa were Blastocystis, followed by Entamoeba histolytica complex, and Giardia intestinalis both as mono-parasites and as part of multiple parasites. Molecular assays showed that Blastocystis ST3, Entamoeba dispar, Giardia intestinalis assemblage B, and Cryptosporidium hominis were the most prevalent species. Intestinal parasitic infection was significantly associated with age, gender, residence, and water source. Multi-parasitism showed that residency in a rural area was a risk factor (OR 4.49; 95% CI 1.51-13.37; P = 0.007). Egyptians residing in rural areas have a high prevalence of intestinal multi-parasitism. Therefore, to lessen the prevalence and effects of these infections in this group, effective and sustainable control methods, providing health education focusing on good personal hygiene habits, and providing a safe drinking water supply should be implemented.
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Affiliation(s)
- Eman S El-Wakil
- Department of Parasitology, Theodor Bilharz Research Institute, Kornaish El-Nile St., Giza, 12411, Egypt.
| | - Rabab S Zalat
- Department of Parasitology, Theodor Bilharz Research Institute, Kornaish El-Nile St., Giza, 12411, Egypt
| | - Ayman A El-Badry
- Department of Microbiology-Medical Parasitology Section, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
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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
| | - 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
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Davey ML, Kamenova S, Fossøy F, Solberg EJ, Davidson R, Mysterud A, Rolandsen CM. Faecal metabarcoding provides improved detection and taxonomic resolution for non-invasive monitoring of gastrointestinal nematode parasites in wild moose populations. Parasit Vectors 2023; 16:19. [PMID: 36653864 PMCID: PMC9847159 DOI: 10.1186/s13071-022-05644-6] [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: 07/06/2022] [Accepted: 12/28/2022] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Although wild ungulate populations are heavily monitored throughout Europe, we understand little of how parasites affect population dynamics, and there is no systematic, long-term monitoring of parasite diversity and parasite loads. Such monitoring is in part hampered by a lack of time- and cost-effective assay methodologies with high sensitivity and good taxonomic resolution. DNA metabarcoding has been successfully used to characterize the parasitic nemabiome with high taxonomic resolution in a variety of wild and domestic hosts. However, in order to implement this technique in large-scale, potentially non-invasive monitoring of gastrointestinal parasitic nematodes (GIN), protocol optimization is required to maximize biodiversity detection, whilst maintaining time- and cost-effectiveness. METHODS Faecal samples were collected from a wild moose population and GIN communities were characterized and quantified using both parasitological techniques (egg and larva counting) and DNA metabarcoding of the ITS2 region of rDNA. Three different isolation methods were compared that differed in the volume of starting material and cell lysis method. RESULTS Similar nematode faunas were recovered from all samples using both parasitological and metabarcoding methods, and the approaches were largely congruent. However, metabarcoding assays showed better taxonomic resolution and slightly higher sensitivity than egg and larvae counts. The metabarcoding was not strictly quantitative, but the proportion of target nematode sequences recovered was correlated with the parasitologically determined parasite load. Species detection rates in the metabarcoding assays were maximized using a DNA isolation method that included mechanical cell disruption and maximized the starting material volume. CONCLUSIONS DNA metabarcoding is a promising technique for the non-invasive, large-scale monitoring of parasitic GINs in wild ungulate populations, owing to its high taxonomic resolution, increased assay sensitivity, and time- and cost-effectiveness. Although metabarcoding is not a strictly quantitative method, it may nonetheless be possible to create a management- and conservation-relevant index for the host parasite load from this data. To optimize the detection rates and time- and cost-effectiveness of metabarcoding assays, we recommend choosing a DNA isolation method that involves mechanical cell disruption and maximizes the starting material volume.
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Affiliation(s)
- Marie L. Davey
- grid.420127.20000 0001 2107 519XNorwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Stefaniya Kamenova
- grid.5510.10000 0004 1936 8921University of Oslo, Oslo, Norway ,grid.19477.3c0000 0004 0607 975XNorwegian University of Life Sciences, Ås, Norway
| | - Frode Fossøy
- grid.420127.20000 0001 2107 519XNorwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Erling J. Solberg
- grid.420127.20000 0001 2107 519XNorwegian Institute for Nature Research (NINA), Trondheim, Norway
| | - Rebecca Davidson
- grid.410549.d0000 0000 9542 2193Norwegian Veterinary Institute, Tromsø, Norway
| | - Atle Mysterud
- grid.420127.20000 0001 2107 519XNorwegian Institute for Nature Research (NINA), Trondheim, Norway ,grid.5510.10000 0004 1936 8921University of Oslo, Oslo, Norway
| | - Christer M. Rolandsen
- grid.420127.20000 0001 2107 519XNorwegian Institute for Nature Research (NINA), Trondheim, Norway
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18
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Kamdem CN, Fogue PS, Tiofack AAZ, Mewamba EM, Womeni HM, Koffi M, Simo G. Assessment of cetyl-trimethyl-ammonium bromide (CTAB) based method for the extraction of soil-transmitted helminth DNAs from stools for molecular dagnostic of soil-transmitted helminthiasis. J Microbiol Methods 2023; 204:106661. [PMID: 36565938 DOI: 10.1016/j.mimet.2022.106661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/18/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Although several protocols were developed to extract DNA for soil-transmitted helminthiasis diagnostic, amplifying these extracts remains challenging due to DNA polymerase inhibitors. This study aimed to assess a DNA extraction method for efficient detection of soil-transmitted helminth species by determining stool mass and the type of DNA polymerase that can be used for this extraction method. For this study, 141 stool samples harbouring soil-transmitted eggs and 50 samples without egg were obtained from school-aged children of Makenene in the Centre region of Cameroon. DNA was extracted from 10, 20, 40 and 80 mg of stool using commercial kit and/or cetyltrimethylammonium bromide (CTAB)-based method. The amount of stool for molecular diagnostic of soil-transmitted helminthiasis was determined by amplifying Ascaris lumbricoides DNA. The performances of three DNA polymerases and CTAB-based method were assessed by amplifying DNA of different soil-transmitted helminth species. For this study, 94 stools with A. lumbricoides eggs, 39 with Trichuris trichuria and 15 with hookworm were analyzed. DNA of A. lumbricoides, T. trichuria, Necator americanus and Ancylostoma duodenale were detected in 97.9% of extracts from stools harbouring soil-transmitted helminth eggs. Soil-transmitted helminth DNAs were significantly (X2 = 17.66; df = 3; p 〈00001) more amplified in extracts from 10 and 20 mg than those from 40 and 80 mg. The amplification rate with "Q5 high fidelity DNA polymerase" was significantly (X2 = 30.54; df = 2; p < 0.00001) higher than that of other DNA polymerases. Multiplex-PCR confirmed co-infections of A. lumbricoides with either T. trichuria or N. americanus. The extraction cost for the CTAB-based method was $1.45. This method appearedis reliable and 3 times cost effective than commercial kit. Its combination with the "Q5 high fidelity DNA polymerase" may improve soil-transmitted helminthiasis diagnostic.
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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
| | - Pythagore Soubgwi Fogue
- Molecular Parasitology and Entomology Unit, Department of Biochemistry, Faculty of Science, University of Dschang, PO. Box 67, Dschang, Cameroon
| | - Arnol Auvaker 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
| | - Hilaire Marcaire Womeni
- "Unité de Recherche de Biochimie, des plantes Médicinales, des Sciences alimentaires et Nutrition", University of Dschang, Dschang, Cameroon
| | - Mathurin Koffi
- "Unité de Recherche en Génétique et Epidémiology Moléculaire, Jean Lorougnon Guédé University", Daloa, Côte d'Ivoire
| | - 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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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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20
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Bahwaireth EO, Wakid MH. Molecular, Microscopic, and Immunochromatographic Detection of Enteroparasitic Infections in Hemodialysis Patients and Related Risk Factors. Foodborne Pathog Dis 2022; 19:830-838. [PMID: 36067331 DOI: 10.1089/fpd.2022.0024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Intestinal parasitic infection (IPI) is one of the important causes of morbidity and mortality in patients with chronic renal failure (CRF). Patients with CRF are more prone to infections due to acquired immunodeficiency caused by uremia. This study aims at determining the prevalence of parasitic intestinal infections in hemodialysis (HD) patients in Makkah, Saudi Arabia, and at comparing the techniques used for the detection of intestinal parasites. One hundred stool samples were collected from Saudi HD patients from two dialysis centers of two hospitals in Makkah City, and 50 samples were collected randomly from healthy individuals that served as control. The laboratory tests were carried out at King Fahd Medical Research Center, King Abdulaziz University, Jeddah. One stool sample was collected from each participant and examined with different techniques. The diagnosis was carried out using the direct wet smear with normal saline and native-Lugol's, Ritchie technique, rapid diagnostic test (ImmunoCard STAT! CGE), and molecular techniques (real-time polymerase chain reaction). The relation between age, gender, weight, and height to calculate body mass index, level of education, time of the HD, lifestyle, residence status, several gastrointestinal symptoms, blood pressure, diabetes, irritable bowel disease, and other factors was studied. Intestinal parasites were found in 38% of the HD patients and 36% of the control group. The most encountered intestinal parasites in the HD patients and control group were Blastocystis hominis (31%) and (34%), Entamoeba histolytica (3%) and (2%) respectively, Endolimax nana (4%) in the HD group, Giardia lamblia (4%) in the control group, and no positive results for Cryptosporidium or helminths in both groups. The IPIs should be suspected in all cases of immunodeficient patients, and stool samples should be ordered as routine with other tests in interval times and examined using special techniques. The physicians should be aware of the similarity between HD and intestinal parasitosis symptoms to perform diagnostic tests and determine the suitable treatment.
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Affiliation(s)
- Ebtihal O Bahwaireth
- Microbiology Section, Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Jeddah, Saudi Arabia
| | - Majed H Wakid
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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21
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Soares FA, Dos Santos BM, Rosa SL, Loiola SHN, Stéfano VC, Proença LR, Suzuki CTN, Sabadini E, Bresciani KDS, Falcão AX, Gomes JF. Detection of intestinal parasites in human faecal samples using dissolved air flotation. Trop Med Int Health 2022; 27:1044-1052. [PMID: 36261920 DOI: 10.1111/tmi.13827] [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: 01/24/2023]
Abstract
OBJECTIVE Ova and parasite (O&P) examination is recommended for the laboratory diagnosis of agents causing parasitic infections; however, this exam requires scientific and technological improvements to enhance its diagnostic validity. Dissolved air flotation (DAF) is an efficient technical principle separating suspended solids in a liquid medium. We aimed to develop and validate a new procedure for intestinal parasite detection with DAF. METHODS In this study, we collected samples from 500 volunteers, screened them by direct examination, and transferred the material to tubes using the Three Faecal Test (TF-Test) for triplicate DAF tests. We evaluated physical-chemical parameters and DAF prototype components through quantifying parasites recovered from floated and non-floated regions of the flotation column. The DAF operation protocol was validated with the gold standard results. RESULTS The 10% saturated volume proportion and cationic surfactant showed regularity and high parasite recovery (80%). Modifications of the needle device did not influence parasite recovery (p > 0.05). Sensitivity, specificity, accuracy and kappa agreement obtained with the DAF protocol were 91%, 100%, 93% and substantial (k = 0.64), respectively. CONCLUSION The DAF principle could be used to process faecal samples in routine laboratory exams, enabling intestinal parasite detection.
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Affiliation(s)
- Felipe Augusto Soares
- School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.,Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Bianca Martins Dos Santos
- School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.,Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Stefany Laryssa Rosa
- School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.,Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Saulo Hudson Nery Loiola
- School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.,Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Vitória Castilho Stéfano
- Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Letícia Rodrigues Proença
- Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Celso Tetsuo Nagase Suzuki
- Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil.,ImmunoCamp Science and Technology, Vinhedo, São Paulo, Brazil
| | - Edvaldo Sabadini
- Institute of Chemistry, Department of Physics-Chemistry, University of Campinas, Campinas, São Paulo, Brazil
| | | | - Alexandre Xavier Falcão
- Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
| | - Jancarlo Ferreira Gomes
- School of Medical Sciences, University of Campinas, Campinas, São Paulo, Brazil.,Institute of Computing (IC), Laboratory of Image Data Science (LIDS), University of Campinas, Campinas, São Paulo, Brazil
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22
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Diagnostic Methods of Common Intestinal Protozoa: Current and Future Immunological and Molecular Methods. Trop Med Infect Dis 2022; 7:tropicalmed7100253. [PMID: 36287994 PMCID: PMC9606991 DOI: 10.3390/tropicalmed7100253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/15/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Intestinal protozoan infection is a persisting public health problem affecting the populations of developing countries in the tropical and subtropical regions. The diagnosis of intestinal protozoa remains a challenge especially in developing countries due to a shortage of laboratory facilities, limited health funding, and the remoteness of communities. Despite still being widely used, conventional diagnoses using microscopy and staining methods pose important limitations, particularly due to their low sensitivities and specificities. The selection of diagnostic methods needs to be carefully considered based on the objective of examination, availability of resources, and the expected parasite to be found. In this review, we describe various immunodiagnosis and molecular diagnostic methods for intestinal protozoa infection, including their advantages, disadvantages, and suitability for different settings, with a focus on Entamoeba histolytica, Giardia duodenalis, and Cryptosporidium spp.
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23
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Buonfrate D, Tamarozzi F, Paradies P, Watts MR, Bradbury RS, Bisoffi Z. The diagnosis of human and companion animal Strongyloides stercoralis infection: Challenges and solutions. A scoping review. ADVANCES IN PARASITOLOGY 2022; 118:1-84. [PMID: 36088083 DOI: 10.1016/bs.apar.2022.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Strongyloidiasis is the infection caused by soil-transmitted nematodes of Strongyloides species, infecting humans and some animals. Strongyloides stercoralis is the species with most clinical and epidemiological relevance in humans and dogs, due to its high prevalence and its capacity of inducing a life-threatening hyperinfection. Diagnosis of strongyloidiasis is challenging, due to the absence of a single reference standard test with high sensitivity and specificity, which also hampers the estimation of the accuracy of other diagnostic tests. In this chapter, we review the deployment and performance of the parasitological, immunological, molecular tests for the diagnosis of strongyloidiasis in humans and in dogs. Further, we comment the available evidence from genotyping studies that have addressed the zoonotic potential of S. stercoralis. Finally, we discuss the use of different diagnostic methods in relation to the purpose (i.e., screening, individual diagnosis, inclusion in a clinical trial) and the setting (endemic/non-endemic areas) and report the accuracy figures reported by systematic reviews on either parasitological, serological or molecular techniques published in literature.
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Affiliation(s)
- Dora Buonfrate
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy.
| | - Francesca Tamarozzi
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy
| | - Paola Paradies
- Department of Emergency and Organs Transplantation, Veterinary Section, Campus of Veterinary Medicine, University of Bari, Bari, Italy
| | - Matthew R Watts
- Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research - New South Wales Health Pathology and Sydney Institute for Infectious Diseases, Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Richard S Bradbury
- School of Health and Life Sciences, Federation University Australia, Berwick, VC, Australia
| | - Zeno Bisoffi
- Department of Infectious Tropical diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Verona, Italy; Department of Diagnostics and Public Health, University of Verona, Verona, Italy
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24
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Rinaldi L, Krücken J, Martinez-Valladares M, Pepe P, Maurelli MP, de Queiroz C, Castilla Gómez de Agüero V, Wang T, Cringoli G, Charlier J, Gilleard JS, von Samson-Himmelstjerna G. Advances in diagnosis of gastrointestinal nematodes in livestock and companion animals. ADVANCES IN PARASITOLOGY 2022; 118:85-176. [PMID: 36088084 DOI: 10.1016/bs.apar.2022.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Diagnosis of gastrointestinal nematodes in livestock and companion animals has been neglected for years and there has been an historical underinvestment in the development and improvement of diagnostic tools, undermining the undoubted utility of surveillance and control programmes. However, a new impetus by the scientific community and the quickening pace of technological innovations, are promoting a renaissance of interest in developing diagnostic capacity for nematode infections in veterinary parasitology. A cross-cutting priority for diagnostic tools is the development of pen-side tests and associated decision support tools that rapidly inform on the levels of infection and morbidity. This includes development of scalable, parasite detection using artificial intelligence for automated counting of parasitic elements and research towards establishing biomarkers using innovative molecular and proteomic methods. The aim of this review is to assess the state-of-the-art in the diagnosis of helminth infections in livestock and companion animals and presents the current advances of diagnostic methods for intestinal parasites harnessing (i) automated methods for copromicroscopy based on artificial intelligence, (ii) immunodiagnosis, and (iii) molecular- and proteome-based approaches. Regardless of the method used, multiple factors need to be considered before diagnostics test results can be interpreted in terms of control decisions. Guidelines on how to apply diagnostics and how to interpret test results in different animal species are increasingly requested and some were recently made available in veterinary parasitology for the different domestic species.
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Affiliation(s)
- Laura Rinaldi
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy.
| | - J Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
| | - M Martinez-Valladares
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
| | - P Pepe
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | - M P Maurelli
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | - C de Queiroz
- Faculty of Veterinary Medicine, 3331 Hospital Drive, Host-Parasite Interactions (HPI) Program University of Calgary, Calgary, Alberta, Canada; Faculty of Veterinary Medicine, St Georges University, Grenada
| | - V Castilla Gómez de Agüero
- Instituto de Ganadería de Montaña (CSIC-Universidad de León), Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de León, León, Spain
| | - T Wang
- Kreavet, Kruibeke, Belgium
| | - Giuseppe Cringoli
- Department of Veterinary Medicine and Animal Production, University of Naples "Federico II", Naples, Italy
| | | | - J S Gilleard
- Faculty of Veterinary Medicine, 3331 Hospital Drive, Host-Parasite Interactions (HPI) Program University of Calgary, Calgary, Alberta, Canada
| | - G von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
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25
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Alqarni AS, Wakid MH, Gattan HS. Prevalence, type of infections and comparative analysis of detection techniques of intestinal parasites in the province of Belgarn, Saudi Arabia. PeerJ 2022; 10:e13889. [PMID: 35975233 PMCID: PMC9375965 DOI: 10.7717/peerj.13889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/21/2022] [Indexed: 01/19/2023] Open
Abstract
Background The study was conducted to observe the prevalence and type of infection caused by intestinal parasites and to compare the techniques that are available for the detection. Method A total of 112 stool samples were obtained from study participants, and the laboratory examinations were performed at Special Infectious Agents Unit, King Abdulaziz University, Jeddah. One hundred and twelve participants were included in this study. Result The color of positive specimens was mainly brown (86.4%). Stool consistency in infected cases was soft in (64%) samples. There was no statistically significant difference with the physical characteristics of the stool (P > 0.05). In total, 59 of the 112 participants were infected with intestinal parasites, representing 52.7%. Different intestinal protozoa parasites were identified in which Blastocystis hominis (86.4%) was highest. None of the intestinal helminths were detected. Out of the 59 infected cases, single infections were found in (62.7%) samples. The intestinal protozoan parasites in single infections were B. hominis (78.4%), Giardia lamblia (8.1%), and (2.7%) from each Entamoeba histolytica, Cryptosporidium parvum, Entamoeba coli, Endolimax nana, and Chilomastix mesnili. Microscopy, RDTs, and real-time PCR were used for detection and identification of G. lamblia, E. histolytica, and C. parvum. Conclusion The study reported a high rate of intestinal parasitic infections, mainly with B. hominis. There were no statistical differences in parasite detection between the three techniques in detection of the thirteen cases infected with the pathogenic protozoa.
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Affiliation(s)
- Abdulrahman S. Alqarni
- Health Affairs, Sabt Al-Alaya General Hospital, Directorate of Health Affairs, Ministry of Health, Bisha, Saudi Arabia
| | - Majed H. Wakid
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia,Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hattan S. Gattan
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia,Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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26
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Chapman PR, Llewellyn S, Jennings H, Becker L, Giacomin P, McDougall R, Robson J, Loukas A, McCarthy J. The production of Necator americanus larvae for use in experimental human infection. Parasit Vectors 2022; 15:242. [PMID: 35804460 PMCID: PMC9264692 DOI: 10.1186/s13071-022-05371-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/03/2022] [Indexed: 11/10/2022] Open
Abstract
Background Although there is unprecedented interest in experimental human hookworm infection, details of hookworm manufacture and characterisation have been sparsely reported. In this report, we detail the production and characterisation of Necator americanus larvae for use in a recently published clinical trial. Methods Faeces was obtained from an experimentally infected donor. Faecal hookworm DNA was determined by quantitative PCR. Paired samples were incubated in either sterile water or sterile water mixed with antimicrobials (amphotericin and gentamicin). Coproculture was performed by modified Harada-Mori method. The harvested larvae were then processed in either sterile water or antiseptic solution. Larval yield was then calculated (larvae per gram), larval viability was determined by thermally induced motility assay and microbial burden was determined at the day of harvest, at 48 h and at 7 days. Results Twenty-eight faecal cultures were performed over 16 months. The faecal hookworm DNA content was variable over this time. There was no association of larval yield with faecal hookworm DNA content. Pre-treatment of faeces with antimicrobials did not influence larval yield. Larval motility was 85.3% (95% CI 79.3–91.3%). Incubation of larvae in antiseptics did not reduce viability at 14 days with a marginal mean of 68.6% (95% CI 59.1–78.1%) washed in water vs. 63.3% (95% CI 53.8 – 72.9%) when incubated in betadine (p = 0.38). Larvae washed in sterile water did not meet microbial bioburden criteria. Incubation in antiseptic resulted in acceptable microbial bioburden at 48 h but not at 7 days. Although the addition of gentamicin did reduce the microbial bio-burden acceptable levels, it was found to significantly lower larval motility at 7 days compared to incubation in sterile water and motility at 7 days 37.8% (95% CI 4.7–70.9%) vs. 67.3% (95% CI 35.2–99.3%, p < 0.001), respectively. Conclusions Despite standardised culture methodologies and the use of a single donor, larval yield varied considerably between batches and had no association with faecal hookworm DNA. Larval viability decreases over time and the age of larvae at time of use are likely to be important. Microbial bioburden maybe temporarily reduced by incubation in antiseptics and has little effect on viability. Incubation of larvae in gentamicin is effective at reducing microbial bioburden but is deleterious to larval viability. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05371-y.
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Affiliation(s)
- Paul R Chapman
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia. .,RBWH Infectious Diseases, Bowen Hills and Herston, Australia.
| | - Stacey Llewellyn
- Statistics Unit, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Helen Jennings
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Luke Becker
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Paul Giacomin
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Rodney McDougall
- Sullivan Nicolaides Pathology, Bowen Hills and Herston, Australia
| | - Jennifer Robson
- Sullivan Nicolaides Pathology, Bowen Hills and Herston, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - James McCarthy
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
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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: 8] [Impact Index Per Article: 4.0] [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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Papaiakovou M, Littlewood DTJ, Doyle SR, Gasser RB, Cantacessi C. Worms and bugs of the gut: the search for diagnostic signatures using barcoding, and metagenomics-metabolomics. Parasit Vectors 2022; 15:118. [PMID: 35365192 PMCID: PMC8973539 DOI: 10.1186/s13071-022-05225-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 02/25/2022] [Indexed: 02/07/2023] Open
Abstract
Gastrointestinal (GI) helminth infections cause significant morbidity in both humans and animals worldwide. Specific and sensitive diagnosis is central to the surveillance of such infections and to determine the effectiveness of treatment strategies used to control them. In this article, we: (i) assess the strengths and limitations of existing methods applied to the diagnosis of GI helminth infections of humans and livestock; (ii) examine high-throughput sequencing approaches, such as targeted molecular barcoding and shotgun sequencing, as tools to define the taxonomic composition of helminth infections; and (iii) discuss the current understanding of the interactions between helminths and microbiota in the host gut. Stool-based diagnostics are likely to serve as an important tool well into the future; improved diagnostics of helminths and their environment in the gut may assist the identification of biomarkers with the potential to define the health/disease status of individuals and populations, and to identify existing or emerging anthelmintic resistance.
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Affiliation(s)
- Marina Papaiakovou
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
- Department of Life Sciences, Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | | | | | - Robin B. Gasser
- Melbourne Veterinary School, The University of Melbourne, Parkville, VIC 3010 Australia
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
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Aung E, Han KT, Gordon CA, Hlaing NN, Aye MM, Htun MW, Wai KT, Myat SM, Thwe TL, Tun A, Wangdi K, Li Y, Williams GM, Clements ACA, Vaz Nery S, McManus DP, Gray DJ. High prevalence of soil-transmitted helminth infections in Myanmar schoolchildren. Infect Dis Poverty 2022; 11:28. [PMID: 35272701 PMCID: PMC8908594 DOI: 10.1186/s40249-022-00952-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/21/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Achieving the elimination of soil-transmitted helminth (STH) infections requires a sufficient understanding of the current epidemiological status of STH endemicity. We aimed to examine the status of STH in Myanmar - a country with the eighth highest STH prevalence in the world, 10 years after instigation of the national deworming programme. METHODS In August 2016 we screened for STH infections using Kato Katz (KK) microscopy and real-time PCR (qPCR) in schoolchildren from the Bago Region township of Phyu, a STH sentinel site in Myanmar. Ten schools were randomly selected, and one stool sample each from a total of 264 students was examined. Prevalence and intensity of infection were calculated for each STH. RESULTS High prevalence of STH was identified in the study area with 78.8% of the schoolchildren infected with at least one STH by qPCR, and 33.3% by KK. The most prevalent STH was Trichuris trichiura, diagnosed by both KK (26.1%) and qPCR (67.1%), followed by Ascaris lumbricoides (15.5% KK; 54.9% qPCR). No hookworm infections were identified by KK; however, the qPCR analysis showed a high prevalence of Ancylostoma sp. infection (29.6%) with few Necator americanus (1.1%) infections. CONCLUSIONS Despite bi-annual deworming of schoolchildren in the fourth-grade and below, STH prevalence remains stubbornly high. These results informed the expansion of the Myanmar National STH control programme to include all school-aged children by the Ministry of Health and Sports in 2017, however further expansion to the whole community should be considered along with improving sanitation and hygiene measures. This would be augmented by rigorous monitoring and evaluation, including national prevalence surveys.
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Affiliation(s)
- Eindra Aung
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
- St Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Kay Thwe Han
- Parasitology Research Division, Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Catherine A Gordon
- Infectious Diseases Program, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | | | - Moe Moe Aye
- Department of Zoology, University of Yangon, Yangon, Myanmar
| | - Myo Win Htun
- Parasitology Research Division, Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Khin Thet Wai
- Parasitology Research Division, Department of Medical Research, Ministry of Health and Sports, Yangon, Myanmar
| | - Su Mon Myat
- Department of Public Health, Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Thida Lay Thwe
- Department of Zoology, University of Yangon, Yangon, Myanmar
| | - Aung Tun
- Ministry of Health and Sports, Nay Pyi Taw, Myanmar
| | - Kinley Wangdi
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
| | - Yuesheng Li
- Infectious Diseases Program, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
- Hunan Institute of Parasitic Diseases, World Health Organization Collaborating Centre for Research and Control On Schistosomiasis in Lake Region, Yueyang, China
| | - Gail M Williams
- School of Public Health, University of Queensland, Brisbane, QLD, Australia
| | - Archie C A Clements
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
- Faculty of Health Sciences, Curtin University, Perth, WA, Australia
| | - Susana Vaz Nery
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia
- The Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Donald P McManus
- Infectious Diseases Program, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Darren J Gray
- Department of Global Health, Research School of Population Health, Australian National University, Canberra, ACT, Australia.
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McKay PA, Hufschmid J, Meredith AL, Zendejas-Heredia PA, Moseby KE. Seroprevalence of Toxoplasma gondii in burrowing bettongs (Bettongia lesueur): a comparison of cat-free and cat-exposed populations. AUST J ZOOL 2022. [DOI: 10.1071/zo22010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Oliveira LM, Oliveira YLDC, Oliveira YLM, Ramos ACS, Andrade GF, Sá VL, Geraldi RM, Pinheiro CS, Bueno LL, Fujiwara RT, Dolabella SS. Intestinal polyparasitism and levels of mucosal anthelmintic SIgA in children from endemic areas in Northeastern Brazil. Parasite Immunol 2021; 44:e12899. [PMID: 34861047 DOI: 10.1111/pim.12899] [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: 09/01/2021] [Revised: 11/20/2021] [Accepted: 11/29/2021] [Indexed: 11/29/2022]
Abstract
Interactions between parasites during co-infections are often complex and can impact immunization and treatment programmes, as well as disease outcomes and morbidity. However, little is known about these interactions and the mechanisms involved. In this study, a coproparasitological survey was carried out in school-age children living in endemic areas of parasitic infection in the state of Sergipe, Northeastern Brazil. Anti-helminth-specific and total secretory immunoglobulin-A (SIgA) levels were measured in stool and saliva samples and were compared in children presenting monoparasitism, polyparasitism (helminths and/or intestinal protozoa) and no infections. The survey showed that protozoa were more prevalent than helminths, and that there was a high frequency of polyparasitism in the studied population, mainly from combinations of protozoan species. Although less frequent, combinations between species of protozoa and helminths were also observed. The levels of salivary SIgA in these co-infected individuals were lower than the average observed in infections with helminths alone. Although the children participating in this survey were asymptomatic, and it was, therefore, not possible to evaluate the impact of salivary SIgA reduction on the diseases, and the study highlights the need for further investigations of co-infections by intestinal parasites and the effects on immune response induced by the interactions between different parasites.
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Affiliation(s)
- Luciana M Oliveira
- Postgraduate Program in Parasite Biology, Universidade Federal de Sergipe, São Cristóvão, Brazil.,Department of Morphology, Universidade Federal de Sergipe, São Cristovão, Brazil
| | - Yvanna L D C Oliveira
- Postgraduate Program in Pharmaceutical Sciences, Universidade Federal de Sergipe, São Cristóvão, Brazil
| | - Yrna L M Oliveira
- Postgraduate Program in Parasite Biology, Universidade Federal de Sergipe, São Cristóvão, Brazil
| | - Anne Caroline S Ramos
- Postgraduate Program in Parasite Biology, Universidade Federal de Sergipe, São Cristóvão, Brazil
| | - Gabriela F Andrade
- Department of Morphology, Universidade Federal de Sergipe, São Cristovão, Brazil
| | - Vitor L Sá
- Department of Morphology, Universidade Federal de Sergipe, São Cristovão, Brazil
| | - Ricardo M Geraldi
- Department of Morphology, Universidade Federal de Sergipe, São Cristovão, Brazil
| | - Carina S Pinheiro
- Department of Biointeraction, Institute of Health Sciences, Universidade Federal da Bahia, Salvador, Brazil
| | - Lilian L Bueno
- Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ricardo T Fujiwara
- Postgraduate Program in Parasite Biology, Universidade Federal de Sergipe, São Cristóvão, Brazil.,Department of Parasitology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Silvio S Dolabella
- Postgraduate Program in Parasite Biology, Universidade Federal de Sergipe, São Cristóvão, Brazil.,Department of Morphology, Universidade Federal de Sergipe, São Cristovão, Brazil
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Soares FA, Martins Dos Santos B, Rosa SL, Loiola SHN, Suzuki CTN, Sabadini E, Bresciani KDS, Falcão AX, Gomes JF. Dissolved air flotation as potential new mechanism for intestinal parasite diagnosis in feces. Acta Trop 2021; 224:106137. [PMID: 34562419 DOI: 10.1016/j.actatropica.2021.106137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/17/2021] [Accepted: 09/15/2021] [Indexed: 01/08/2023]
Abstract
The parasitological examination of feces is recommended for the laboratory diagnosis of intestinal parasites due to its practicality, low-cost, and moderate diagnostic sensitivity. Dissolved Air Flotation (DAF) is an efficient technical principle used in other areas to separate dispersed solids. This study sought the preliminary evaluation of a proof-of-concept prototype as a tool for detecting species of parasites by adjusting DAF. Two DAF prototype units were developed to evaluate microbubbles' generation amidst fecal suspension and parasites' capture. For this evaluation, samples were screened and processed by the TF-Test technique (Control) and simultaneously by DAF device. The dimensional and attachment characteristics in the formation of the microbubbles were evaluated, and the percentage of parasitic recovery in floated and not-floated regions compared by Student's t-test. The second prototype unit proved to be more efficient in forming microbubbles with diameters between 34 and 170µm. The flotation tests showed a recovery of 73.27%, 58.12%, 37.85%, and 91.89% for Ascaris lumbricoides, Hymenolepis diminuta, Giardia duodenalis, and Strongyloides stercoralis, respectively. This study confirmed the selective interaction between microbubbles and parasite eggs and larvae during the flotation process using the DAF principle for the first time through imaging.
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Affiliation(s)
- Felipe Augusto Soares
- School of Medical Sciences, University of Campinas, Campinas, São Paulo 13083-889, Brazil; Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil.
| | - Bianca Martins Dos Santos
- School of Medical Sciences, University of Campinas, Campinas, São Paulo 13083-889, Brazil; Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil
| | - Stefany Laryssa Rosa
- School of Medical Sciences, University of Campinas, Campinas, São Paulo 13083-889, Brazil; Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil
| | - Saulo Hudson Nery Loiola
- School of Medical Sciences, University of Campinas, Campinas, São Paulo 13083-889, Brazil; Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil
| | - Celso Tetsuo Nagase Suzuki
- Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil; ImmunoCamp Science and Technology, Vinhedo, São Paulo, Brazil
| | - Edvaldo Sabadini
- Department of Physical-Chemistry, Institute of Chemistry, University of Campinas, Campinas, São Paulo, Brazil
| | | | - Alexandre Xavier Falcão
- Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil
| | - Jancarlo Ferreira Gomes
- School of Medical Sciences, University of Campinas, Campinas, São Paulo 13083-889, Brazil; Laboratory of Image Data Science (LIDS), Institute of Computing (IC), University of Campinas, Campinas, São Paulo, Brazil
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Chapman PR, Webster R, Giacomin P, Llewellyn S, Becker L, Pearson MS, De Labastida Rivera F, O'Rourke P, Engwerda CR, Loukas A, McCarthy JS. Vaccination of human participants with attenuated Necator americanus hookworm larvae and human challenge in Australia: a dose-finding study and randomised, placebo-controlled, phase 1 trial. THE LANCET. INFECTIOUS DISEASES 2021; 21:1725-1736. [PMID: 34419209 PMCID: PMC9760122 DOI: 10.1016/s1473-3099(21)00153-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 02/05/2021] [Accepted: 03/04/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Control of human hookworm infection would be greatly aided by the development of an effective vaccine. We aimed to develop a live attenuated human hookworm vaccine. METHODS This was a two-part clinical trial done at Q-Pharm in Brisbane (QLD, Australia) using a live ultraviolet C (UVC)-attenuated Necator americanus larvae vaccine. Part one was an open-label, dose-finding study using 50 L3 larvae suspended in water to a volume of 200 μL, attenuated with UVC exposure of 700 μJ (L3-700) or 1000 μJ (L3-1000). Part two was a randomised, double-blind, placebo-controlled, challenge study, in which participants were randomly assigned 2:1 to the vaccine group or placebo group. Healthy hookworm-naive adults aged 18-65 years with body-mass index 18-35 kg/m2 received two doses of either placebo (Tabasco sauce) or vaccine (50 L3-700) on day 1 and day 42, followed by challenge with 30 unattenuated L3 larvae to both groups. All participants received a single oral dose of 400 mg albendazole 4 weeks after each inoculation and a 3-day course (400 mg orally daily) initiated on day 161 after the challenge phase, to eliminate any remaining infection. The primary outcome of part 1 was the level of larval attenuation the resulted in a grade 2 or 3 dermal adverse event. The primary outcome of part 2 was safety and tolerability, assessed by frequency and severity of adverse events in all randomly assigned participants. Prespecified exploratory outcomes in the challenge study were faecal N americanus DNA concentration, the number of N americanus larvae recovered per g of faeces cultured, hookworm antigen-specific serum IgG antibody responses, and hookworm antigen-specific peripheral blood cytokine responses. The trial is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12617001007325). FINDINGS Between Sept 19, 2017, and Oct 24, 2018, seven participants were enrolled into three cohorts in part one (two participants in cohort 1, who received L3-700; two participants in cohort 2, who received L3-700; and three participants in cohort 3, who received L3-1000) and a further 15 were enrolled into part two. There were no serious adverse events in part one or part two. In part one, a greater number of skin penetration sites were observed after administration of L3-700 than L3-1000 (mean 15·75 [95% CI 11·18 to 20·32] with L3-700 vs 4·33 [-1·40 to 10·07] with L3-1000). Similarly, greater erythema (median 225 mm2 [IQR 150 to 325] vs 25 mm2 [12·5 to 80]) and a longer duration of the dermal reaction (median 8·0 days [IQR 3·5 to 11·5] vs 2·0 days [2·0 to 4·5]) were observed after L3-700 than L3-1000. The mean number of adverse events per participant did not differ between the groups (3·25 [95% CI 1·48 to 5·02] vs 3·00 [1·04 to 4·96]). Thus, L3-700 was used for vaccination in part two. In part two, ten participants were randomly assigned to receive L3-700 and five to placebo. Significantly more adverse events occurred after vaccination with attenuated larvae than with placebo (incident rate ratio [IRR] 2·13 [95% CI 2·09 to 5·51]; p=0·0030). There was no difference between groups in the frequency of adverse events after challenge (IRR 1·25 [0·78 to 2·01]; p=0·36). Most adverse events were mild in severity, with only one severe adverse event reported (erythematous and indurated pruritic rash >100 mm in a vaccine group participant after challenge). The eosinophil count increased in all participants after challenge, with a significantly greater increase among vaccinated participants than placebo participants (1·55 × 109 cells per L [IQR 0·92 to 1·81] in the vaccine group vs 0·49 × 109 cells per L [0·43 to 0·63] in the placebo group; p=0·014). Vaccinated participants had an IgG response to larval extract after challenge that was higher than that in placebo participants (increase in IgG titre 0·22 [IQR 0·10 to 0·41] vs 0·03 [-0·40 to 0·06]; p=0·020). Significantly fewer larvae per g of faeces were recovered in the vaccine group than in the placebo group after challenge (median larvae per g 0·8 [IQR 0·00 to 3·91] vs 10·2 [5·1 to 18·1]; p=0·014). The concentration of N americanus DNA in faeces was not significantly different between the vaccinated group and the placebo group (log10 DNA intensity 4·28 [95% CI 3·92 to 4·63] vs 4·88 [4·31 to 5·46]; p=0·14). Peripheral blood mononuclear cells from vaccinated participants exhibited significantly greater cytokine production at day 112 than placebo participants for IFNγ, TNFα, IL-2, IL-4, and IL-5 (p<0·05), but not IL-10. INTERPRETATION Vaccination with UVC-attenuated N americanus larvae is well tolerated, induces humoral and cellular responses to hookworm antigens, and reduces larval output after challenge with unattenuated larvae. Larger studies are required to confirm protective efficacy. FUNDING National Health and Medical Research Council of Australia.
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Affiliation(s)
- Paul R Chapman
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia; Infectious Diseases Unit, Royal Brisbane and Women's Hospital, Herston, QLD, Australia.
| | - Rebecca Webster
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Paul Giacomin
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Stacey Llewellyn
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Luke Becker
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Mark S Pearson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Fabian De Labastida Rivera
- Immunology and Infection Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Peter O'Rourke
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Christian R Engwerda
- Immunology and Infection Laboratory, Department of Immunology, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - James S McCarthy
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia; Infectious Diseases Unit, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
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Chapman PR, Giacomin P, Loukas A, McCarthy JS. Experimental human hookworm infection: a narrative historical review. PLoS Negl Trop Dis 2021; 15:e0009908. [PMID: 34882670 PMCID: PMC8659326 DOI: 10.1371/journal.pntd.0009908] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In 1896, a serendipitous laboratory accident led to the understanding that hookworms propagate infection by penetrating skin, a theory that was then confirmed with the first experimental human infection, reported in 1901. Experimental human infections undertaken in the 20th century enabled understanding of the natural history of infection and the immune response. More recently, experimental hookworm infection has been performed to investigate the immunomodulatory potential of hookworm infection and for the evaluation of hookworm vaccines and chemotherapeutic interventions. Experimental human hookworm infection has been proven to be safe, with no deaths observed in over 500 participants (although early reports predate systematic adverse event reporting) and no serious adverse events described in over 200 participants enrolled in contemporary clinical trials. While experimental human hookworm infection holds significant promise, as both a challenge model for testing anti-hookworm therapies and for treating various diseases of modernity, there are many challenges that present. These challenges include preparation and storage of larvae, which has not significantly changed since Harada and Mori first described their coproculture method in 1955. In vitro methods of hookworm larval culture, storage, and the development of meaningful potency or release assays are required. Surrogate markers of intestinal infection intensity are required because faecal egg counts or hookworm faecal DNA intensity lack the fidelity required for exploration of hookworm infection as a vaccine/drug testing platform or as a regulated therapy.
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Affiliation(s)
- Paul R. Chapman
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, Australia
- Infectious Diseases Unit, Royal Brisbane and Women’s Hospital, Herston, Australia
| | - Paul Giacomin
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | - James S. McCarthy
- Clinical Tropical Medicine, QIMR Berghofer Medical Research Institute, Herston, Australia
- Infectious Diseases Unit, Royal Brisbane and Women’s Hospital, Herston, 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: 4] [Impact Index Per Article: 1.3] [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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Byrne A, Manalo G, Clarke NE, Vaz Nery S. Impact of hookworm infection and preventive chemotherapy on haemoglobin in non-pregnant populations. Trop Med Int Health 2021; 26:1568-1592. [PMID: 34587315 DOI: 10.1111/tmi.13681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To assess the impact of hookworm infection and preventive chemotherapy on haemoglobin levels in non-pregnant populations in endemic areas. METHOD Systematic review and meta-analysis searching PubMed and Web of Science for articles published since 2010 reporting either hookworm prevalence and Hb concentration (cross-sectional studies) or Hb concentration before and after the implementation of preventive chemotherapy (before-after studies and randomised controlled trials [RCTs]). For papers published before 2010, data were extracted from a previously published systematic review. Random effects meta-analyses were conducted to examine the relationship between Hb concentration and hookworm infection intensity (from cross-sectional studies) and the effect of preventive chemotherapy on Hb concentration (from before-after studies and RCTs). Sensitivity analyses investigated the impact of malaria endemicity and combined interventions for schistosomiasis and nutrition status on Hb concentration. RESULTS Among cross-sectional studies, both light- and heavy-intensity hookworm infections were associated with lower Hb in school-aged children. School-aged children with heavy hookworm infection in settings of high malaria endemicity had lower mean Hb than those in settings of low malaria endemicity. In non-pregnant populations, deworming with albendazole was associated with an increase in Hb of 3.02 g/L (95% CI 0.1, 6.0 g/L). No additional benefit was seen with deworming using albendazole co-administered with praziquantel for schistosomiasis infection or iron supplementation for nutrition status. CONCLUSION Our findings confirm the benefits of preventive chemotherapy as a public health intervention.
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Affiliation(s)
- Aisling Byrne
- Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Giselle Manalo
- School of Public Health, University of Sydney, Sydney, NSW, Australia
| | - Naomi E Clarke
- Kirby Institute, University of New South Wales, Sydney, NSW, Australia
| | - Susana Vaz Nery
- Kirby Institute, University of New South Wales, Sydney, NSW, Australia
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Cantera JL, White HN, Forrest MS, Stringer OW, Belizario VY, Storey HL, de Hostos EL, de los Santos T. Sensitive and semiquantitative detection of soil-transmitted helminth infection in stool using a recombinase polymerase amplification-based assay. PLoS Negl Trop Dis 2021; 15:e0009782. [PMID: 34516554 PMCID: PMC8459997 DOI: 10.1371/journal.pntd.0009782] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 09/23/2021] [Accepted: 09/01/2021] [Indexed: 01/03/2023] Open
Abstract
Background Soil-transmitted helminths (STHs) are parasitic nematodes that inhabit the human intestine. They affect more than 1.5 billion people worldwide, causing physical and cognitive impairment in children. The global strategy to control STH infection includes periodic mass drug administration (MDA) based on the results of diagnostic testing among populations at risk, but the current microscopy method for detecting infection has diminished sensitivity as the intensity of infection decreases. Thus, improved diagnostic tools are needed to support decision-making for STH control programs. Methodology We developed a nucleic acid amplification test based on recombinase polymerase amplification (RPA) technology to detect STH in stool. We designed primers and probes for each of the four STH species, optimized the assay, and then verified its performance using clinical stool samples. Principal findings Each RPA assay was as sensitive as a real-time polymerase chain reaction (PCR) assay in detecting copies of cloned target DNA sequences. The RPA assay amplified the target in DNA extracted from human stool samples that were positive for STH based on the Kato-Katz method, with no cross-reactivity of the non-target genomic DNA. When tested with clinical stool samples from patients with infections of light, moderate, and heavy intensity, the RPA assays demonstrated performance comparable to that of real-time PCR, with better results than Kato-Katz. This new rapid, sensitive and field-deployable method for detecting STH infections can help STH control programs achieve their goals. Conclusions Semi-quantitation of target by RPA assay is possible and is comparable to real-time PCR. With proper instrumentation, RPA assays can provide robust, semi-quantification of STH DNA targets as an alternative field-deployable indicator to counts of helminth eggs for assessing infection intensity. More than 1.5 billion people are infected with parasitic intestinal worms called soil-transmitted helminths. Infection is transmitted by helminth eggs in human feces, which contaminate soil in areas with poor sanitation. Adverse health effects include physical and cognitive impairment in children. A key strategy to control infection is periodic mass drug administration for populations with a high prevalence of disease based on the results of diagnostic testing. The current microscopy method for detecting infection, however, has limited ability to detect disease as the intensity of infection decreases with repeated mass drug administration. To address limitations of current diagnostic methods, we developed a novel technique to diagnose infections, including those at very low levels of intensity, by detecting helminth DNA in stool samples. Our initial studies suggest that the new diagnostic technique reliably detects the presence of intestinal worms, even at low intensities of infection, and may be more useful than currently available diagnostic tools for guiding the use of periodic mass drug administration to eliminate disease in low-resource settings.
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Affiliation(s)
| | | | | | | | - Vicente Y. Belizario
- Department of Parasitology, College of Public Health, University of the Philippines, Ermita, Manila, Philippines
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Dacal E, Bermejo-Peláez D, Lin L, Álamo E, Cuadrado D, Martínez Á, Mousa A, Postigo M, Soto A, Sukosd E, Vladimirov A, Mwandawiro C, Gichuki P, Williams NA, Muñoz J, Kepha S, Luengo-Oroz M. Mobile microscopy and telemedicine platform assisted by deep learning for the quantification of Trichuris trichiura infection. PLoS Negl Trop Dis 2021; 15:e0009677. [PMID: 34492039 PMCID: PMC8448303 DOI: 10.1371/journal.pntd.0009677] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 09/17/2021] [Accepted: 07/21/2021] [Indexed: 11/18/2022] Open
Abstract
Soil-transmitted helminths (STH) are the most prevalent pathogens among the group of neglected tropical diseases (NTDs). The Kato-Katz technique is the diagnosis method recommended by the World Health Organization (WHO) although it often presents a decreased sensitivity in low transmission settings and it is labour intensive. Visual reading of Kato-Katz preparations requires the samples to be analyzed in a short period of time since its preparation. Digitizing the samples could provide a solution which allows to store the samples in a digital database and perform remote analysis. Artificial intelligence (AI) methods based on digitized samples can support diagnosis by performing an objective and automatic quantification of disease infection. In this work, we propose an end-to-end pipeline for microscopy image digitization and automatic analysis of digitized images of STH. Our solution includes (a) a digitization system based on a mobile app that digitizes microscope samples using a 3D printed microscope adapter, (b) a telemedicine platform for remote analysis and labelling, and (c) novel deep learning algorithms for automatic assessment and quantification of parasitological infections by STH. The deep learning algorithm has been trained and tested on 51 slides of stool samples containing 949 Trichuris spp. eggs from 6 different subjects. The algorithm evaluation was performed using a cross-validation strategy, obtaining a mean precision of 98.44% and a mean recall of 80.94%. The results also proved the potential of generalization capability of the method at identifying different types of helminth eggs. Additionally, the AI-assisted quantification of STH based on digitized samples has been compared to the one performed using conventional microscopy, showing a good agreement between measurements. In conclusion, this work has presented a comprehensive pipeline using smartphone-assisted microscopy. It is integrated with a telemedicine platform for automatic image analysis and quantification of STH infection using AI models.
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Affiliation(s)
| | | | - Lin Lin
- Spotlab, Madrid, Spain
- Biomedical Image Technologies, ETSI Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | | | | | | | | | | | | | | | | | - Charles Mwandawiro
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Paul Gichuki
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
| | - Nana Aba Williams
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - José Muñoz
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Stella Kepha
- Eastern and Southern Africa Center for International Parasite Control (ESACIPAC), Kenya Medical Research Institute (KEMRI), Nairobi, Kenya
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Wolday D, Gebrecherkos T, Arefaine ZG, Kiros YK, Gebreegzabher A, Tasew G, Abdulkader M, Abraha HE, Desta AA, Hailu A, Tollera G, Abdella S, Tesema M, Abate E, Endarge KL, Hundie TG, Miteku FK, Urban BC, Schallig HHDF, Harris VC, de Wit TFR. Effect of co-infection with intestinal parasites on COVID-19 severity: A prospective observational cohort study. EClinicalMedicine 2021; 39:101054. [PMID: 34368662 DOI: 10.1101/2021.02.02.21250995] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 05/28/2023] Open
Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in a spectrum of clinical presentations. Evidence from Africa indicates that significantly less COVID-19 patients suffer from serious symptoms than in the industrialized world. We and others previously postulated a partial explanation for this phenomenon, being a different, more activated immune system due to parasite infections. Here, we aimed to test this hypothesis by investigating a potential correlation of co-infection with parasites with COVID-19 severity in an endemic area in Africa. Methods: Ethiopian COVID-19 patients were enrolled and screened for intestinal parasites, between July 2020 and March 2021. The primary outcome was the proportion of patients with severe COVID-19. Ordinal logistic regression models were used to estimate the association between parasite infection, and COVID-19 severity. Models were adjusted for sex, age, residence, education level, occupation, body mass index, and comorbidities. Findings: 751 SARS-CoV-2 infected patients were enrolled, of whom 284 (37.8%) had intestinal parasitic infection. Only 27/255 (10.6%) severe COVID-19 patients were co-infected with intestinal parasites, while 257/496 (51.8%) non-severe COVID-19 patients were parasite positive (p<0.0001). Patients co-infected with parasites had lower odds of developing severe COVID-19, with an adjusted odds ratio (aOR) of 0.23 (95% CI 0.17-0.30; p<0.0001) for all parasites, aOR 0.37 ([95% CI 0.26-0.51]; p<0.0001) for protozoa, and aOR 0.26 ([95% CI 0.19-0.35]; p<0.0001) for helminths. When stratified by species, co-infection with Entamoeba spp., Hymenolepis nana, Schistosoma mansoni, and Trichuris trichiura implied lower probability of developing severe COVID-19. There were 11 deaths (1.5%), and all were among patients without parasites (p = 0.009). Interpretation: Parasite co-infection is associated with a reduced risk of severe COVID-19 in African patients. Parasite-driven immunomodulatory responses may mute hyper-inflammation associated with severe COVID-19. Funding: European and Developing Countries Clinical Trials Partnership (EDCTP) - European Union, and Joep Lange Institute (JLI), The Netherlands. Trial registration: Clinicaltrials.gov: NCT04473365.
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Affiliation(s)
- Dawit Wolday
- Mekelle University College of Health Sciences, Mekelle, Ethiopia
| | | | | | | | | | - Geremew Tasew
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | | | | | | | | | - Saro Abdella
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | - Ebba Abate
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | | | | | - Britta C Urban
- Department of Clinical Sciences, Respiratory Clinical Research Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Henk H D F Schallig
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology Unit, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Vanessa C Harris
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology Unit, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam Institute of Global Health and Development, Department of Global Health, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Tobias F Rinke de Wit
- Amsterdam Institute of Global Health and Development, Department of Global Health, Amsterdam University Medical Center, Amsterdam, the Netherlands
- Joep Lange Institute, Amsterdam, the Netherlands
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41
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Wolday D, Gebrecherkos T, Arefaine ZG, Kiros YK, Gebreegzabher A, Tasew G, Abdulkader M, Abraha HE, Desta AA, Hailu A, Tollera G, Abdella S, Tesema M, Abate E, Endarge KL, Hundie TG, Miteku FK, Urban BC, Schallig HH, Harris VC, de Wit TFR. Effect of co-infection with intestinal parasites on COVID-19 severity: A prospective observational cohort study. EClinicalMedicine 2021; 39:101054. [PMID: 34368662 PMCID: PMC8324426 DOI: 10.1016/j.eclinm.2021.101054] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 01/08/2023] Open
Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in a spectrum of clinical presentations. Evidence from Africa indicates that significantly less COVID-19 patients suffer from serious symptoms than in the industrialized world. We and others previously postulated a partial explanation for this phenomenon, being a different, more activated immune system due to parasite infections. Here, we aimed to test this hypothesis by investigating a potential correlation of co-infection with parasites with COVID-19 severity in an endemic area in Africa. Methods: Ethiopian COVID-19 patients were enrolled and screened for intestinal parasites, between July 2020 and March 2021. The primary outcome was the proportion of patients with severe COVID-19. Ordinal logistic regression models were used to estimate the association between parasite infection, and COVID-19 severity. Models were adjusted for sex, age, residence, education level, occupation, body mass index, and comorbidities. Findings: 751 SARS-CoV-2 infected patients were enrolled, of whom 284 (37.8%) had intestinal parasitic infection. Only 27/255 (10.6%) severe COVID-19 patients were co-infected with intestinal parasites, while 257/496 (51.8%) non-severe COVID-19 patients were parasite positive (p<0.0001). Patients co-infected with parasites had lower odds of developing severe COVID-19, with an adjusted odds ratio (aOR) of 0.23 (95% CI 0.17-0.30; p<0.0001) for all parasites, aOR 0.37 ([95% CI 0.26-0.51]; p<0.0001) for protozoa, and aOR 0.26 ([95% CI 0.19-0.35]; p<0.0001) for helminths. When stratified by species, co-infection with Entamoeba spp., Hymenolepis nana, Schistosoma mansoni, and Trichuris trichiura implied lower probability of developing severe COVID-19. There were 11 deaths (1.5%), and all were among patients without parasites (p = 0.009). Interpretation: Parasite co-infection is associated with a reduced risk of severe COVID-19 in African patients. Parasite-driven immunomodulatory responses may mute hyper-inflammation associated with severe COVID-19. Funding: European and Developing Countries Clinical Trials Partnership (EDCTP) - European Union, and Joep Lange Institute (JLI), The Netherlands. Trial registration: Clinicaltrials.gov: NCT04473365.
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Affiliation(s)
- Dawit Wolday
- Mekelle University College of Health Sciences, Mekelle, Ethiopia
| | | | | | | | | | - Geremew Tasew
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | | | | | | | | | - Saro Abdella
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | - Ebba Abate
- Ethiopian Public Health institute, Addis Ababa, Ethiopia
| | | | | | | | - Britta C. Urban
- Department of Clinical Sciences, Respiratory Clinical Research Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Henk H.D.F. Schallig
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology Unit, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Vanessa C. Harris
- Department of Medical Microbiology and Infection Prevention, Experimental Parasitology Unit, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam Institute of Global Health and Development, Department of Global Health, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Tobias F. Rinke de Wit
- Amsterdam Institute of Global Health and Development, Department of Global Health, Amsterdam University Medical Center, Amsterdam, the Netherlands
- Joep Lange Institute, Amsterdam, the Netherlands
- Corresponding author: at Amsterdam Institute of Global Health and Development, Department of Global Health, Amsterdam University Medical Center, Amsterdam, the Netherlands
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Dacal E, Köster PC, Carmena D. Diagnóstico molecular de parasitosis intestinales. Enferm Infecc Microbiol Clin 2021; 38 Suppl 1:24-31. [PMID: 32111362 DOI: 10.1016/j.eimc.2020.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Infections causes by parasites of the gastrointestinal tract are a global public health problem. In industrialised countries, their particular epidemiological (low general prevalence of enteroparasites), economic (high labour costs) and clinical characteristics (constant increase in the number of samples and diagnostic determinations to be performed) have led molecular techniques to progressively replace conventional microscopy as the first-line diagnostic method of these pathogens in modern clinical laboratories. PCR-based techniques, particularly those developed for the simultaneous detection of the various agents that can cause the same infectious disease (syndromic diagnosis), already represent a cost-effective option that allow process automisation, workflow optimisation, and comparison of results among different laboratories, and facilitate accreditation of diagnostic procedures. This review clearly and concisely discusses the current situation of the molecular diagnosis of the main species of intestinal parasites in humans, particularly the enteric protozoans causing diarrhoea (Cryptosporidium spp., Giardia duodenalis, Entamoeba histolytica), the most important members the Microsporidia phyla (Enterocytozoon bieneusi) and Stramenopiles phyla (Blastocystis sp.), as well as the helminths transmitted by soil (Ancylostoma spp., Ascaris lumbricoides, Necator americanus, Strongyloides stercoralis and Trichuris trichiura) and food (Anisakis spp., Clonorchis sinensis, Fasciola spp., Taenia solium, and Trichinella spiralis). Special attention is paid to the description of available techniques and formats, to their diagnostic benefits and the most widely used genetic markers for their detection, both in clinical laboratories and genotyping in referral and research centres.
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Affiliation(s)
- Elena Dacal
- Laboratorio de Referencia e Investigación en Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España
| | - Pamela C Köster
- Laboratorio de Referencia e Investigación en Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España
| | - David Carmena
- Laboratorio de Referencia e Investigación en Parasitología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, España.
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Randomized, Placebo Controlled Trial of Experimental Hookworm Infection for Improving Gluten Tolerance in Celiac Disease. Clin Transl Gastroenterol 2021; 11:e00274. [PMID: 33512796 PMCID: PMC7678792 DOI: 10.14309/ctg.0000000000000274] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION: Celiac disease is an autoimmune disorder where intestinal immunopathology arises after gluten consumption. Previous studies suggested that hookworm infection restores gluten tolerance; however, these studies were small (n = 12) and not placebo controlled. METHODS: We undertook a randomized, placebo-controlled trial of hookworm infection in 54 people with celiac disease. The 94-week study involved treatment with either 20 or 40 Necator americanus third-stage larvae (L3-20 or L3-40) or placebo, followed by escalating gluten consumption (50 mg/d for 12 weeks, 1 g intermittent twice weekly for 12 weeks, 2 g/d sustained for 6 weeks, liberal diet for 1 year). RESULTS: Successful study completion rates at week 42 (primary outcome) were similar in each group (placebo: 57%, L3-20: 37%, and L3-40: 44%; P = 0.61), however gluten-related adverse events were significantly reduced in hookworm-treated participants: Median (range) adverse events/participant were as follows: placebo, 4 (1–9); L3-20, 1 (0–9); and L3-40, 0 (0–3) (P = 0.019). Duodenal villous height:crypt depth deteriorated similarly compared with their enrolment values in each group (mean change [95% confidence interval]: placebo, −0.6 [−1.3 to 0.2]; L3-20, −0.5 [−0.8 to 0.2]; and L3-40, −1.1 [−1.8 to 0.4]; P = 0.12). A retrospective analysis revealed that 9 of the 40 L3-treated participants failed to establish hookworm infections. Although week 42 completion rates were similar in hookworm-positive vs hookworm-negative participants (48% vs 44%, P = 0.43), quality of life symptom scores were lower in hookworm-positive participants after intermittent gluten challenge (mean [95% confidence interval]: 38.9 [33.9–44] vs 45.9 [39.2–52.6]). DISCUSSION: Hookworm infection does not restore tolerance to sustained moderate consumption of gluten (2 g/d) but was associated with improved symptom scores after intermittent consumption of lower, intermittent gluten doses.
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Gillardie ML, Babba O, Mahinc C, Duthel M, de Bengy C, Morineaud C, Rivollier E, Flori P. Molecular approach to the epidemiology of urinary schistosomiasis in France. PLoS Negl Trop Dis 2021; 15:e0009515. [PMID: 34228747 PMCID: PMC8284649 DOI: 10.1371/journal.pntd.0009515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 07/16/2021] [Accepted: 05/28/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The diagnosis of urogenital schistosomiasis is based on the complementarity of serological technique and microscopic examination (ME). Between 2015 and 2019, the number of urinary schistosomiasis tests received in our laboratory increased sharply from 300 to 900 per year. Therefore, we wanted to evaluate the reliability of urine microscopic examination (ME, reference and routine technique) from urine sample by comparing it to other techniques (antigenic technique and PCR). To this end, we optimized two real-time PCRs targeting respectively Schistosoma haematobium (Sh) and Schistosoma mansoni (Sm). METHODOLOGY/PRINCIPAL FINDINGS 914 urine samples from 846 patients suspected of urogenital schistosomiasis were prescribed and analyzed by PCR and also by antigenic technique for the first 143 samples. The antigenic technique evaluated was Schisto POC-CCA, Rapid Medical Diagnostics. These results (antigenic technique and PCR) were compared to ME which was performed from all urines. The percentage of 14% (128/914) positive cases with the PCR technique and the percentage of 6.0% (54/914) positive cases with ME is significantly different (Chi 2 test, p<0.001). These 128 positive PCRs correspond to 120 different patients, 88.3% (106/120) of them were young migrants and 11.7% (14/120) were French patients returning from travel. Among these migrants, more than 75% (80/106) came from French-speaking West Africa. In addition, the Schisto POC-CCA showed a specificity of 39% (46/117), too poor to be used as a screening tool in low or non-endemic areas. CONCLUSION/SIGNIFICANCE Targeted Sh and Sm PCRs in urine are reliable techniques compared to ME (reference technique). In view of our results, we decided to screen urinary schistosomiasis by direct ME always coupled by the PCR technique, which has shown better reliability criteria.
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Affiliation(s)
- Marie-Laure Gillardie
- University of Saint-Etienne, GIMAP-EA-3064, Saint Etienne, France
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Oussama Babba
- University of Saint-Etienne, GIMAP-EA-3064, Saint Etienne, France
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Caroline Mahinc
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Maureen Duthel
- University of Saint-Etienne, GIMAP-EA-3064, Saint Etienne, France
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Claire de Bengy
- University of Saint-Etienne, GIMAP-EA-3064, Saint Etienne, France
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
| | - Clotilde Morineaud
- Department of Public Health, University Hospital of Poitiers, Poitiers, France
| | - Elisabeth Rivollier
- Department PASS, University Hospital of Saint-Etienne, Saint Etienne, France
| | - Pierre Flori
- University of Saint-Etienne, GIMAP-EA-3064, Saint Etienne, France
- Parasitology and Mycology, department of Infectious Agents and Hygiene, University Hospital of Saint-Etienne, Saint-Etienne, France
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Zendejas-Heredia PA, Colella V, Hii SF, Traub RJ. Comparison of the egg recovery rates and limit of detection for soil-transmitted helminths using the Kato-Katz thick smear, faecal flotation and quantitative real-time PCR in human stool. PLoS Negl Trop Dis 2021; 15:e0009395. [PMID: 34038411 PMCID: PMC8153506 DOI: 10.1371/journal.pntd.0009395] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/17/2021] [Indexed: 01/02/2023] Open
Abstract
Background Monitoring the success of soil-transmitted helminth (STH) control programs relies on accurate diagnosis and quantitative assessment of infection prevalence and intensity. As preventative chemotherapeutic program coverage for STH expands, the necessity of gaining insights into the relative or comparative sensitivities, in terms of limits of detection (LOD) and egg-recovery-rates (ERR) for microscopy and quantitative polymerase chain reaction qPCR-based diagnostic techniques becomes imperative to inform suitability for their intended use for large scale STH monitoring and treatment efficacy studies. Methodology/Principal findings The diagnostic performance in terms of ERR and LOD of the Kato-Katz (KK) thick smear technique, sodium nitrate (NaNO3) faecal floatation (FF) and qPCR for the accurate detection and enumeration of STH eggs were calculated and expressed in eggs per gram (EPG), by experimentally seeding parasite-free human faeces with Ascaris spp., Trichuris spp. and Necator americanus eggs representing low, medium and high intensity infections. The efficiency of NaNO3 flotation was also calculated over a range of specific gravities (SpGr) for the optimum recovery of STH eggs. FF of SpGr 1.30 recovered 62.7%, 11% and 8.7% more Trichuris spp., Necator americanus and Ascaris spp. eggs respectively, than the recommended SpGr of 1.20. All diagnostic methods demonstrated strong direct correlation to the intensity of seeded EPG. KK and FF (SpGr 1.30) resulted in significant lower ERRs compared to qPCR (p <0.05). qPCR demonstrated significantly (p <0.05) greater sensitivity with an ability to detect as little as 5 EPG for all three STH, compared to 50 EPG by KK and FF (SpGr 1.30). Conclusions/Significance This study compares the diagnostic parameters in terms of LOD and ERRs of STHs for the KK, FF and qPCR. These results indicate that the diagnostic performance of qPCR assays should be considered by control programs in the phase that aims to seek confirmation of transmission break and cessation of preventive chemotherapy in low-transmission settings, in line with the control targets of the WHO neglected tropical diseases 2030 Roadmap. STH infections predominately affect resource-poor communities and negatively impact on child and maternal health. Diagnostics play a critical role in guiding and informing existing STH control programs and the implementation and evaluation of intervention strategies. The KK technique is most commonly used as per WHO guidelines and is the basis for determining quantitative thresholds for low, moderate and heavy infections. More recently, FF and laboratory-based quantitative PCR techniques have provided alternative options of diagnosing STH infections. A number of studies correlating the relative sensitivity, diagnostic agreement, and egg enumeration of these techniques by comparing field-generated diagnostic data have attempted to correlate quantitative outputs to those defined by the WHO, with little resolution. Moreover, as large-scale deworming programs levels scale up, the necessity to apply techniques that can precisely detect light infections is of outmost importance to establish preventive chemotherapy end-points using more accurate means. In this study we compared the LOD and ERR of seeded non-infected human faecal samples with Ascaris, Trichuris and Necator spp. eggs using KK, FF and qPCR. When compared to copro-microscopy methods, qPCR showed the highest sensitivity for the detection of light-intensity infections and was more accurate in enumerating the original number of eggs per gram of seeded faeces. In addition to this, the results indicated that the diagnostic performance of both KK and FF (using solution at a SpGr of 1.30) were equally efficient and should be considered with their diagnostic limitations in mind, when aiming to monitor STH infections in low-transmission settings.
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Affiliation(s)
- Patsy A. Zendejas-Heredia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | - Vito Colella
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Sze Fui Hii
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Rebecca J. Traub
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
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Papaiakovou M, Littlewood DTJ, Gasser RB, Anderson RM. How qPCR complements the WHO roadmap (2021-2030) for soil-transmitted helminths. Trends Parasitol 2021; 37:698-708. [PMID: 33931342 DOI: 10.1016/j.pt.2021.04.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/02/2021] [Accepted: 04/08/2021] [Indexed: 12/19/2022]
Abstract
Complementing the launch of the World Health Organization (WHO) roadmap (2021-2030) we explore key elements needing attention before recruitment of qPCR as the main diagnostics tool to confirm reduction or elimination of soil-transmitted helminth (STH) transmission in both control and elimination programmes. Given the performance limitations of conventional methods, a proposed harmonised qPCR will provide a diagnostic tool, with the sensitivity and specificity required to monitor low-intensity infections, following mass drug administration (MDA). Technical and logistical challenges associated with introducing qPCR as a stand-alone tool are highlighted, and a decision-making scheme on how qPCR can support surveillance, resistance detection, and elimination is presented. An accurate point-of-care (POC) diagnostic test needs to be developed to support STH control in the field, and STH biorepositories need to be established and maintained to ensure that reference materials are available for research and validation.
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Affiliation(s)
- Marina Papaiakovou
- Department of Infectious Disease Epidemiology, St Mary's Campus, Imperial College London, London, UK; London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College London, London, UK.
| | - D Timothy J Littlewood
- Science Directorate, Natural History Museum, London, UK; London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College London, London, UK
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Roy M Anderson
- Department of Infectious Disease Epidemiology, St Mary's Campus, Imperial College London, London, UK; London Centre for Neglected Tropical Disease Research (LCNTDR), Imperial College London, London, UK
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Habib A, Andrianonimiadana L, Rakotondrainipiana M, Andriantsalama P, Randriamparany R, Randremanana RV, Rakotoarison R, Vigan-Womas I, Rafalimanantsoa A, Vonaesch P, Sansonetti PJ, Collard JM. High prevalence of intestinal parasite infestations among stunted and control children aged 2 to 5 years old in two neighborhoods of Antananarivo, Madagascar. PLoS Negl Trop Dis 2021; 15:e0009333. [PMID: 33878113 PMCID: PMC8087024 DOI: 10.1371/journal.pntd.0009333] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 04/30/2021] [Accepted: 03/25/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND This study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques. METHODOLOGY/PRINCIPAL FINDINGS Fecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2-5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques. A total of 96.3% of the children were infested with at least one intestinal parasite. The most prevalent parasites were Giardia intestinalis (79.5%), Ascaris lumbricoides (68.3%) and Trichuris trichiura (68.0%). For all parasites studied, real-time PCR showed higher detection rates compared to microscopy (G. intestinalis [77.6% (n = 318) versus 20.9% (n = 86)], Entamoeba histolytica [15.8% (n = 65) versus 1.9% (n = 8)] and A. lumbricoides [64.1% (n = 263) versus 50.7% (n = 208)]). Among the different variables assessed in the study, age of 4 to 5 years (AOR = 4.61; 95% CI, (1.35-15.77)) and primary and secondary educational level of the mother (AOR = 12.59; 95% CI, (2.76-57.47); AOR = 9.17; 95% CI, (2.12-39.71), respectively) were significantly associated with IPIs. Children drinking untreated water was associated with infestation with G. intestinalis (AOR = 1.85; 95% CI, (1.1-3.09)) and E. histolytica (AOR = 1.9; 95% CI, (1.07-3.38)). E. histolytica was also associated with moderately stunted children (AOR = 0.37; 95% CI, 0.2-0.71). Similarly, children aged between 4 and 5 years (AOR = 3.2; 95% CI (2.04-5.01)) and living on noncemented soil types (AOR = 1.85; 95% CI, (1.18-2.09)) were associated with T. trichiura infestation. CONCLUSIONS/SIGNIFICANCE The prevalence of IPIs is substantial in the studied areas in both stunted and control children, despite the large-scale drug administration of antiparasitic drugs in the country. This high prevalence of IPIs warrants further investigation. Improved health education, environmental sanitation and quality of water sources should be provided.
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Affiliation(s)
- Azimdine Habib
- Unité de Bactériologie Expérimentale, Institut Pasteur de Madagascar, Antananarivo, Madagascar
- * E-mail:
| | - Lova Andrianonimiadana
- Unité de Bactériologie Expérimentale, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | - Prisca Andriantsalama
- Unité d’Epidémiologie et de Recherche Clinique, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Ravaka Randriamparany
- Unité d’Epidémiologie et de Recherche Clinique, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | - Rado Rakotoarison
- Unité d’Immunologie des Maladies Infectieuses, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Inès Vigan-Womas
- Unité d’Immunologie des Maladies Infectieuses, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | - Pascale Vonaesch
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur Paris, France
| | | | - Jean-Marc Collard
- Unité de Bactériologie Expérimentale, Institut Pasteur de Madagascar, Antananarivo, Madagascar
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Autier B, Gangneux JP, Robert-Gangneux F. Evaluation of the Allplex™ GI-Helminth(I) Assay, the first marketed multiplex PCR for helminth diagnosis. ACTA ACUST UNITED AC 2021; 28:33. [PMID: 33812465 PMCID: PMC8019563 DOI: 10.1051/parasite/2021034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 03/18/2021] [Indexed: 11/20/2022]
Abstract
Molecular biology has been gaining more importance in parasitology. Recently, a commercial multiplex PCR assay detecting helminths was marketed: the Allplex™ GI-Helminth(I) Assay. It targets Ancylostoma spp., Ascaris spp., Enterobius vermicularis, Hymenolepis spp., Necator americanus, Strongyloides spp., Taenia spp. and Trichuris trichiura, but also the two most common microsporidia genera in human health, i.e. Enterocytozoon spp. and Encephalitozoon spp. This study aimed to evaluate and compare the Allplex™ GI-Helminth(I) Assay to classical diagnostic methods, based on a cohort of 110 stool samples positive for helminths (microscopy) or for microsporidia (PCR). Samples were stored at −80 °C until analysis by the Allplex™ GI-Helminth(I) Assay. False-negatives were re-tested with bead-beating pretreatment. Without mechanical lysis, concordance and agreement between microscopy and Allplex™ GI-Helminth(I) Assay ranged from 91% to 100% and from 0.15 to 1.00, respectively depending on the target. Concordance was perfect for Taenia spp. (n = 5) and microsporidia (n = 10). False-negative results were observed in 54% (6/13), 34% (4/11) and 20% (7/35) of cases, for hookworms, E. vermicularis and Strongyloides spp. detection, respectively. For these targets, pretreatment improved the results, but only slightly. Trichuris trichiura detection was critically low without pretreatment, as only 9% (1/11) of the samples were positive, but detection reached 91% (10/11) with bead-beating pretreatment. Mechanical lysis was also needed for Ascaris spp. and Hymenolepis spp. to reduce false-negative results from 1/8 to 1/21, respectively, to none for both. Overall, with an optimized extraction process, the Allplex™ GI-Helminth(I) Assay allows the detection of numerous parasites with roughly equivalent performance to that of microscopy, except for hookworms.
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Affiliation(s)
- Brice Autier
- Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMRS 1085, 35000 Rennes, France
| | - Jean-Pierre Gangneux
- Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMRS 1085, 35000 Rennes, France
| | - Florence Robert-Gangneux
- Université de Rennes, CHU Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé Environnement Travail), UMRS 1085, 35000 Rennes, France
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Aw JYH, Clarke NE, Mayfield HJ, Lau CL, Richardson A, Vaz Nery S. Novel statistical approaches to identify risk factors for soil-transmitted helminth infection in Timor-Leste. Int J Parasitol 2021; 51:729-739. [PMID: 33798561 PMCID: PMC8378505 DOI: 10.1016/j.ijpara.2021.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/31/2020] [Accepted: 01/03/2021] [Indexed: 12/02/2022]
Abstract
We compared logistic regression, recursive partitioning and Bayesian networks to identify risk factors for STH infection. Logistic regression identified fewest variables associated with STH infections compared with the two alternative methods. Recursive partitioning identified more demographic and WASH variables, and Bayesian networks more environmental variables. Model performance was similar across all three statistical techniques. Recursive partitioning can identify at-risk population subgroups, while Bayesian networks can run real-time scenarios.
Soil-transmitted helminths (STHs) are parasitic intestinal worms that infect almost a fifth of the global population. Sustainable control of STHs requires understanding the complex interaction of factors contributing to transmission. Identifying risk factors has mainly relied on logistic regression models where the underlying assumption of independence between variables is not always satisfied. Previously demonstrated risk factors including water, sanitation and hygiene (WASH) access and behaviours, and socioeconomic status are intrinsically linked. Similarly, environmental factors including climate, soil and land attributes are often strongly correlated. Alternative methods such as recursive partitioning and Bayesian networks can handle correlated variables, but there are no published studies comparing these methods with logistic regression in the context of STH risk factor analysis. Baseline cross-sectional data from school-aged children in the (S)WASH-D for Worms study were used to compare risk factors identified from modelling the same data using three different statistical techniques. Outcomes of interest were infection with Ascaris spp. and any hookworm species (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum). Mixed-effects logistic regression identified the fewest risk factors. Recursive partitioning identified the most WASH and demographic risk factors, while Bayesian networks identified the most environmental risk factors. Recursive partitioning produced classification trees that visualised potentially at-risk population sub-groups. Bayesian networks helped visualise relationships between variables and enabled interactive modelling of outcomes based on different scenarios for the predictor variables of interest. Model performance was similar across all techniques. Risk factors identified across all techniques were vegetation for Ascaris spp., and cleaning oneself with water after defecating for hookworm. This study adds to the limited body of evidence exploring alternative data modelling approaches in identifying risk factors for STH infections. Our findings suggest these approaches can provide novel insights for more robust interpretation.
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Affiliation(s)
- Jessica Yi Han Aw
- Research School of Population Health, Australian National University, Canberra, Australia.
| | - Naomi E Clarke
- Research School of Population Health, Australian National University, Canberra, Australia; Kirby Institute, University of New South Wales, Sydney, Australia
| | - Helen J Mayfield
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Colleen L Lau
- Research School of Population Health, Australian National University, Canberra, Australia
| | - Alice Richardson
- Statistical Consulting Unit, Australian National University, Canberra, Australia
| | - Susana Vaz Nery
- Kirby Institute, University of New South Wales, Sydney, Australia
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Stracke K, Adisakwattana P, Phuanukoonnon S, Yoonuan T, Poodeepiyasawat A, Dekumyoy P, Chaisiri K, Roth Schulze A, Wilcox S, Karunajeewa H, Traub RJ, Jex AR. Effective low-cost preservation of human stools in field-based studies for helminth and microbiota analysis. Int J Parasitol 2021; 51:741-748. [PMID: 33774039 DOI: 10.1016/j.ijpara.2021.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 12/19/2022]
Abstract
Molecular studies of gastrointestinal infections or microbiotas require either rapid sample processing or effective interim preservation. This is difficult in remote settings in low-income countries, where the majority of the global infectious disease burden exists. Processing or freezing of samples immediately upon collection is often not feasible and the cost of commercial preservatives is prohibitive. We compared fresh freezing (the 'gold standard' method), with low-cost chemical preservation in (i) a salt-based buffer consisting of DMSO, EDTA and NaCl (DESS) or (ii) 2.5% potassium dichromate (PD), for soil-transmitted helminth detection and microbiota characterisation in pre-school and school-aged children from north-western Thailand. Fresh frozen samples were frozen at -20°C on collection and maintained at -80°C within ~3 days of collection until molecular analysis, with international shipping on dry ice. In contrast, chemically preserved samples were collected and stored at ~4°C, transported on wet ice and only stored at -20°C on arrival in Australia ~8 weeks after collection, with international shipping on wet ice. DESS and PD provided better sensitivity for STH diagnosis, estimating higher infection rates (>80% for Ascaris lumbricoides and >60% for Trichuris trichiura; versus 56% and 15% for these parasites in fresh frozen samples) and egg abundance (inferred as gene copy number estimates). All methods performed similarly for microbiota preservation, showing no significant differences in alpha-diversity based on overall richness or inverted Simpson's Index. All three methods performed similarly for RNA and protein preservation in a small subset of samples. Overall, DESS provided the best performance, with the added benefit of being non-toxic, compared with PD, hence making it particularly applicable for studies in remote and resource-poor settings.
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Affiliation(s)
- Katharina Stracke
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medical Biology, The Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia.
| | - Poom Adisakwattana
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Suparat Phuanukoonnon
- Social and Environmental Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Tippayarat Yoonuan
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Akkarin Poodeepiyasawat
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Paron Dekumyoy
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Kittipong Chaisiri
- Department of Helminthology, Faculty for Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Stephen Wilcox
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
| | - Harin Karunajeewa
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Department of Medicine - Western Health, The University of Melbourne, Melbourne, Victoria, Australia
| | - Rebecca J Traub
- Faculty for Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Aaron R Jex
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia; Faculty for Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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