Molecular Characterization of Giardia duodenalis in Children and Adults Sampled in Algeria.

Salem Belkessa,Christen Rune Stensvold,Karim Houali,Daniel Thomas-Lopez,Farida Ghalmi

doi:10.3390/microorganisms9010054

Abstract

The molecular epidemiology of giardiasis in Africa remains unclear. A study was carried out across four hospitals in Algeria. A total of 119 fecal samples from 55 children, 37 adults, and 27 individuals of undetermined age, all scored positive for intestinal parasites by microscopy, and were screened by real-time PCR for Giardia. Molecular characterization of Giardia was performed by assemblage-specific PCR and PCR targeting the triose phosphate isomerase gene (tpi). Of the 119 samples, 80 (67%) were Giardia-positive by real-time PCR. For 48 moderately-highly real-time PCR-positive samples, tpi genotyping assigned 22 samples to Assemblage A and 26 to Assemblage B. Contrary to Assemblage A, Assemblage B exhibited substantial genetic diversity and allelic heterozygosity. Assemblage-specific PCR proved to be specific for discriminating Assemblage A or B but not as sensitive as tpi genotyping. We confirmed that real-time PCR is more sensitive than microscopy for detecting Giardia in stool samples and that robust amplification and sequencing of the tpi gene is feasible when moderate-to-strongly real-time PCR-positive samples are used. This study is one of the few performed in Africa providing genotyping data on Giardia infections in humans. Both assemblages A and B were commonly seen and not associated with specific sociodemographic data.

Highlights

IntroductionEnteric parasites are significant contributors to global diarrheal disease and other intestinal symptoms [1] and, among these, Giardia duodenalis
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.license.Enteric parasites are significant contributors to global diarrheal disease and other intestinal symptoms [1] and, among these, Giardia duodenalis
Symptoms vary in intensity, which may be attributable to both host and parasite factors [6]; infection is considered asymptomatic in approximately 50% of the cases, while severe diarrhea combined with vomiting, bloating, nausea, and/or fatigue can be seen in symptomatic patients, and impaired growth may be seen in children [5]

Summary

Introduction

Enteric parasites are significant contributors to global diarrheal disease and other intestinal symptoms [1] and, among these, Giardia duodenalis Giardia intestinalis) is a flagellated zoonotic parasite commonly found in the intestinal tract of humans and animals, resulting in large numbers of gastrointestinal infections [2]. Up to 280 million people are estimated to be infected with G. duodenalis [2,3,4,5]. The reported prevalence of Giardia infections in humans ranges between 0.4% and 7.5% in developed countries, and between 8% and 30% in developing countries [2]. Symptoms vary in intensity, which may be attributable to both host and parasite factors [6]; infection is considered asymptomatic in approximately 50% of the cases, while severe diarrhea combined with vomiting, bloating, nausea, and/or fatigue can be seen in symptomatic patients, and impaired growth may be seen in children [5]

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Results

Conclusion