Evaluation of a Real-Time Polymerase Chain Reaction for the Laboratory Diagnosis of Giardia intestinalis in Stool Samples from Schoolchildren from the Centre-Ouest and Plateau Central Regions of Burkina Faso

Abstract

Objective: Giardiasis, a zoonotic, diarrheal disease with worldwide occurrence, is routinely diagnosed by microscopic examination of stool samples. However, implementation of this method relies on skilled and experienced personal; it is time consuming and relatively low in sensitivity. A superior diagnostic approach to detect the causative agent Giardia intestinalis would, hence, be highly desirable. The current study aimed to assess realtime polymerase chain reaction (PCR) for the detection of G. intestinalis as an alternative to microscopy. Material and methods: Stool samples from healthy schoolchildren aged 8-14 years from eight schools of the Centre-Ouest and Plateau Central regions in Burkina Faso were therefore collected within a cross-sectional study. Microscopic examination was performed on two faecal samples collected over two consecutive days from 441 schoolchildren. Each faecal specimen has been examined using Kato-Katz and formol-ether methods of concentration in addition to the direct examination. Real-time PCR was used to detect G. intestinalis in the 94 microscopy positive and the 53 microscopy negative samples. Results: Microscopic examination demonstrated an overall G.intestinalis prevalence of 27.2%. Using the microscopic examination as the ‘gold standard’, the overall sensitivity of real-time PCR was demonstrated to be 76.6% ranging from 58.3% to 94.1% and the specificity was 96.2% ranging from 96.2% to 100% across the schools assessed. Conclusion: Real-time PCR appears to be a solid detection method for G. intestinalis in this current setting. However, it needs to be further optimized to become a more sensitive tool for G. intestinalis diagnosis in low income settings.