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There is evolving interest in alternate microscopy techniques and quantitative polymerase chain reaction (qPCR) to evaluate soil-transmitted helminth (STH) burden. Using data from a cross-sectional survey of 540 schoolchildren across six primary schools in three municipalities of Timor-Leste, we compared the performance of microscopy using sodium nitrate flotation (SNF) and qPCR in determining STH prevalence and infection intensity. Prevalence by qPCR was higher than SNF for Ascaris lumbricoides (17.5% versus 11.2%), hookworm (8.3% versus 1.2%), and Trichuris trichiura (4.7% versus 1.6%). Agreement between SNF and qPCR was fair for hookworm (κ = 0.21) and moderate for A. lumbricoides (κ = 0.59) and T. trichiura (κ = 0.44). Moderate or heavy intensity infections were identified in 15.9% of infections detected by SNF, whereas qPCR identified 36.1% as moderate or heavy infections using cycle threshold to eggs per gram conversion formulas. Quantitative PCR is a promising diagnostic technique, though further studies validating infection intensity correlates are required.
Financial support: This research was funded through a Centres of Research Excellence Grant from the National Health and Medical Research Council, Australia (APP1153727).
Editor’s Note: Due to last minute changes requested by the authors, there are differences between the print and online versions of this manuscript. The online version contains these changes; the print version does not.
Authors’ addresses: Adam W. Bartlett, Naomi E. Clarke, and Susana Vaz Nery, University of New South Wales, Kirby Institute, Sydney, Australia, E-mails: email@example.com, firstname.lastname@example.org, and email@example.com. Rebecca Traub and Sze Fui Hii, University of Melbourne, Veterinary and Agricultural Sciences, Melbourne, Victoria, Australia, E-mails: firstname.lastname@example.org and email@example.com. Salvador Amaral and Virginia da Conceicao, Charles Darwin University, Menzies School of Health Research, Darwin, Australia, E-mails: firstname.lastname@example.org and email@example.com. Alexander Matthews, Northern Territory Department of Health, Royal Darwin Hospital, Darwin, Australia, E-mail: firstname.lastname@example.org. Patsy A. Zendejas-Heredia, University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria, Australia, E-mail: email@example.com. Paul Arkell, Charles Darwin University, Menzies School of Health Research, Darwin, Australia, and Imperial College London, Department of Infectious Diseases, London, London, United Kingdom, E-mail: firstname.lastname@example.org. Merita Antonia Armindo Monteiro, Ministry of Health, Department of Communicable Diseases Control, Dili, Timor-Leste, E-mail: email@example.com. Carolina da Costa Maia, Maria Imaculada Soares, and Josefina D. Prisca Guterres, Ministry of Health, National Health Laboratory, Dili, Timor-Leste, E-mails: firstname.lastname@example.org, email@example.com, and firstname.lastname@example.org. Joshua R. Francis, Menzies School of Health Research, Global and Tropical Health, Casuarina, Australia, and Royal Darwin Hospital, Paediatrics, Casuarina, Australia, E-mail: email@example.com.