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PCR-based verification of positive rapid diagnostic tests for intestinal protozoa infections with variable test band intensity
- Source :
- Acta Tropica. 174:49-55
- Publication Year :
- 2017
- Publisher :
- Elsevier BV, 2017.
-
Abstract
- Stool-based rapid diagnostic tests (RDTs) for pathogenic intestinal protozoa (e.g. Cryptosporidium spp. and Giardia intestinalis) allow for prompt diagnosis and treatment in resource-constrained settings. Such RDTs can improve individual patient management and facilitate population-based screening programmes in areas without microbiological laboratories for confirmatory testing. However, RDTs are difficult to interpret in case of 'trace' results with faint test band intensities and little is known about whether such ambiguous results might indicate 'true' infections. In a longitudinal study conducted in poor neighbourhoods of Port Elizabeth, South Africa, a total of 1428 stool samples from two cohorts of schoolchildren were examined on the spot for Cryptosporidium spp. and G. intestinalis using an RDT (Crypto/Giardia DuoStrip; Coris BioConcept). Overall, 121 samples were positive for G. intestinalis and the RDT suggested presence of cryptosporidiosis in 22 samples. After a storage period of 9-10 months in cohort 1 and 2-3 months in cohort 2, samples were subjected to multiplex PCR (BD Max™ Enteric Parasite Panel, Becton Dickinson). Ninety-three percent (112/121) of RDT-positive samples for G. intestinalis were confirmed by PCR, with a correlation between RDT test band intensity and quantitative pathogen load present in the sample. For Cryptosporidium spp., all positive RDTs had faintly visible lines and these were negative on PCR. The performance of the BD Max™ PCR was nearly identical in both cohorts, despite the prolonged storage at disrupted cold chain conditions in cohort 1. The Crypto/Giardia DuoStrip warrants further validation in communities with a high incidence of diarrhoea.
- Subjects :
- Diarrhea
Giardiasis
0301 basic medicine
Veterinary (miscellaneous)
030231 tropical medicine
030106 microbiology
Population
Cryptosporidiosis
Polymerase Chain Reaction
Sensitivity and Specificity
Microbiology
Feces
South Africa
03 medical and health sciences
0302 clinical medicine
parasitic diseases
Multiplex polymerase chain reaction
Animals
Humans
Longitudinal Studies
education
Rapid diagnostic test
education.field_of_study
biology
Incidence (epidemiology)
Becton dickinson
Giardia
Cryptosporidium
biology.organism_classification
Virology
Infectious Diseases
Insect Science
Cohort
Parasitology
Multiplex Polymerase Chain Reaction
Subjects
Details
- ISSN :
- 0001706X
- Volume :
- 174
- Database :
- OpenAIRE
- Journal :
- Acta Tropica
- Accession number :
- edsair.doi.dedup.....6f387e00e6af8efea3f599562e995753