1. Diagnostic performance of a Recombinant Polymerase Amplification Test—Lateral Flow (RPA-LF) for cutaneous leishmaniasis in an endemic setting of Colombia
- Author
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María del Mar Castro, Thomas R. Shelite, Jimena Jojoa, Bruno L. Travi, Alexandra Cossio, Lyda Osorio, Ruth Mabel Castillo, Nancy Gore Saravia, and Peter C. Melby
- Subjects
Male ,RC955-962 ,Recombinase Polymerase Amplification ,Artificial Gene Amplification and Extension ,Pathology and Laboratory Medicine ,Chromatography, Affinity ,law.invention ,Medical Conditions ,0302 clinical medicine ,Filter Paper ,law ,Zoonoses ,Arctic medicine. Tropical medicine ,Medicine and Health Sciences ,Sampling (medicine) ,030212 general & internal medicine ,Child ,Leishmaniasis ,Polymerase chain reaction ,Protozoans ,Leishmania ,Aged, 80 and over ,DNA, Kinetoplast ,Eukaryota ,Middle Aged ,Laboratory Equipment ,Infectious Diseases ,Molecular Diagnostic Techniques ,Child, Preschool ,Engineering and Technology ,Female ,Public aspects of medicine ,RA1-1270 ,Nucleic Acid Amplification Techniques ,Research Article ,Neglected Tropical Diseases ,Adult ,medicine.medical_specialty ,Adolescent ,030231 tropical medicine ,Histopathology ,Equipment ,Leishmaniasis, Cutaneous ,Colombia ,Research and Analysis Methods ,Sensitivity and Specificity ,Young Adult ,03 medical and health sciences ,Signs and Symptoms ,Cutaneous leishmaniasis ,Diagnostic Medicine ,Internal medicine ,Parasitic Diseases ,medicine ,Humans ,Molecular Biology Techniques ,Molecular Biology ,Aged ,DNA Primers ,Protozoan Infections ,business.industry ,Public health ,Organisms ,Public Health, Environmental and Occupational Health ,Biology and Life Sciences ,Gold standard (test) ,DNA, Protozoan ,Tropical Diseases ,medicine.disease ,DNA extraction ,Parasitic Protozoans ,Health Care ,Cross-Sectional Studies ,Anatomical Pathology ,Health Care Facilities ,Lesions ,Clinical Medicine ,business - Abstract
Background Control of cutaneous leishmaniasis by public health systems in the Americas relies on case identification and treatment. Point-of-care diagnostics that can be performed by health workers within or near affected communities could effectively bring the health system to the resource-limited sites providing early diagnosis and treatment, reducing morbidity and the burden of disease. Methodology/principal findings A cross-sectional study was undertaken to evaluate the diagnostic test performance of Isothermal Recombinase Polymerase Amplification (RPA) targeting Leishmania kinetoplast DNA, coupled with a lateral flow (LF) immunochromatographic strip, in a field setting and a laboratory reference center. Minimally invasive swab and FTA filter paper samples were obtained by community health workers and highly trained technicians from ulcerated lesions of > 2 weeks’ evolution from 118 patients’ ≥ 2 years of age in the municipality of Tumaco, Nariño. Extracted DNA was processed by RPA-LF at a reference center or in a primary health facility in the field. Evaluation was based on a composite “gold standard” that included microscopy, culture, biopsy and real-time polymerase chain reaction detection of Leishmania 18S rDNA. Standard of care routine diagnostic tests were explored as comparators. Sensitivity and specificity of RPA-LF in the reference lab scenario were 87% (95%CI 74–94) and 86% (95%CI 74–97), respectively. In the field scenario, the sensitivity was 75% (95%CI 65–84) and specificity 89% (95%CI 78–99). Positive likelihood ratios in both scenarios were higher than 6 while negative likelihood ratios ranged to 0.2–0.3 supporting the usefulness of RPA-LF to rule-in and potentially to rule-out infection. Conclusions/significance The low complexity requirements of RPA-LF combined with non-invasive sampling support the feasibility of its utilization by community health workers with the goal of strengthening the diagnostic capacity for cutaneous leishmaniasis in Colombia. Trial registration ClinicalTrials.gov NCT04500873., Author summary Limited access to diagnosis is a critical determinant of the “neglect” that defines the so-called Neglected Tropical Diseases (NTDs) including cutaneous leishmaniasis. Diagnostic tests that can be performed close to and involve the participation of the affected communities would improve access to treatment as well as diagnosis. Using non-invasive swab and filter paper samples obtained by Community Health Workers, we evaluated the diagnostic performance of an innovative and technically simple molecular test: Isothermal Recombinase Polymerase Amplification (RPA) to detect Leishmania DNA, coupled with a lateral flow (LF) strip to read the results with the naked eye. The RPA-LF test demonstrated high sensitivity and specificity and capacity to rule in or rule out a diagnosis of cutaneous leishmaniasis in both an endemic field setting and reference laboratory. The findings encourage the further optimization of the test format for Point-of-Care diagnosis by health personnel and rural health workers in endemic settings.
- Published
- 2021