Distribution of Giardia duodenalis genotypes in diarrheic children from Algiers, Algeria

Giardia duodenalis is a zoonotic intestinal protozoan that infects humans and a wide range of animals. It is a leading cause of diarrhea worldwide. However, data on the epidemiology of giardiasis in humans and animals in Africa are limited. The present study aimed to genotype G. duodenalis in children from Algiers, Algeria. A total of 447 fecal samples submitted to a medical laboratory were examined for G. duodenalis by microscopy. Of the samples tested, 67 were positive. We performed molecular characterization to determine the G. duodenalis assemblages among the positive samples by analyzing sequences of the triose phosphate isomerase (TPI), beta-giardin (BG), and glutamate dehydrogenase (GDH) genes. PCR analysis of at least one gene revealed that a total of 66 samples were positive. Phylogenetic sequence analysis of the TPI locus identified assemblage A in 36 samples and assemblage B in 15 samples. All assemblage A sequences were determined to be subtype A2. For the BG locus, assemblages A and B were identified in 12 and 13 samples, respectively. For the GDH locus, 36 and 12 samples were identified as assemblages A and B, respectively. Five samples showed mixed infection based on the results of the three analyzed loci. Assemblage A was significantly pore prevalent in children who had diarrhea, attended schools or kindergartens, and drank tap water. This study provides valuable data on the molecular epidemiology of G. duodenalis in Algerian children. Further genotyping- and subtyping-based investigations are needed to better understand transmission dynamics and develop public health measures to control this important parasite.