Microscopic and molecular Cryptosporidium parvum infection in individuals with gastrointestinal symptoms in South Khorasan, Iran

چکیده مقاله

Cryptosporidium spp., an opportunistic protozoan affecting humans and animals, ranks as the third leading global cause of diarrheal disease. Aims: This study aimed to molecularly identify C. parvum in patients with gastrointestinal symptom in Birjand, South Khorasan province, Iran. Methods: Cryptosporidium parvum was molecularly confirmed and characterized using nested PCR and sequencing of the 18S rRNA gene on 160 stool samples from symptomatic patients in Birjand. Phylogenetic analysis was conducted to assess genetic relationships. The resulting phylogenetic trees and haplotype networks were compared. Results: In this study, molecular prevalence was 8.75 (14/160). Sequencing confirmed all positives as C. parvum. Phylogenetic clustering revealed overlap between human isolates and animal-derived strains. Conclusion: Molecular epidemiology is critical for mapping Cryptosporidium transmission. Phylogenetic evidence supports zoonotic cycles in South Khorasan, informing targeted public health strategies.