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

• Published in: Microorganisms (Basel) Vol. 9; no. 1; p. 54
• Main Authors: Belkessa, Salem, Thomas-Lopez, Daniel, Houali, Karim, Ghalmi, Farida, Stensvold, Christen Rune
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 28.12.2020; MDPI
• Subjects: Adults; age; Algeria; allelic sequence heterozygosity (ASH); Children; Deoxyribonucleic acid; diarrhea; DNA; DNA polymerase; Epidemiology; Feces; genes; Genetic diversity; Genetic testing; genetic variation; Genotyping; Giardia; Giardia duodenalis; Giardia lamblia; Giardiasis; Heterozygosity; hospitals; Infections; Intestinal parasites; Intestine; intestines; Laboratories; microorganisms; Microscopy; molecular epidemiology; parasite; Parasites; Polymerase chain reaction; quantitative polymerase chain reaction; Real time; real-time PCR; sampling; Tpi gene; triose-phosphate isomerase; Zoonoses; United States > US; Algeria; Africa; molecular epidemiology; parasite; Giardia duodenalis; real-time PCR; allelic sequence heterozygosity (ASH); diarrhea
• ISSN: 2076-2607; 2076-2607
• DOI: 10.3390/microorganisms9010054

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.