A Survey on Giardia and Cryptosporidium Infection and Genotyping Common Giardia in Children in Alborz Province

Aims: Giardia and Cryptosporidium are enteric protozoans, causing gastrointestinal infection in humans and animals such as mammalian and birds worldwide. Both protozoans causae diarrhea and nutritional disorders in human. The present research aimed at investigating the Giardia and Cryptosporidium infection and genotyping common Giardia in children in Alborz province.

In this descriptive cross sectional study, 160 stool samples of children aged 2-10 years old in Alborz province were first stained with the modified Ziehl-Neelsen staining method for Cryptosporidium and trichrome staining method for Giardia, and they were evaluated for infection with these two protozoans. Then, positive samples were analyzed by molecular method to genotype. Giardia duodenalis based on the TPI gene and Cryptosporidium based on the 18SrRNA gene were investigated by Nested PCR and to determine the groups and subgroups by sequencing. For drawing phylogenetic tree, MEGA 7 software and Maximum liklihood algorithm with 1000 replications were used. Findings: Cryptosporidium was detected in 4 (2.50%) samples, while Giardia was detected in 15 (9.37 %) samples with staining method. In no sample of patients with clinical symptoms of diarrhea, Cryptosporidium was observed. Among 4 isolates of Giardia duodenalis, 1 BIV, 2 BIII, and 1 All isolates were detected, some of which belonged to asymptomatic children and the drawn phylogenetic tree confirmed it. Attempts to determine genotype Cryptosporidium failed.

Identification of AII, BIV, and BIII genotypes in 2-10 years old children in Alborz province indicates anthroponotic and anthropozoonotic transmission of Giardia infection, respectively, in this province.