High prevalence of Cryptosporidium infection in Iranian patients suffering from colorectal cancer

The present investigation was designed to study the prevalence of cryptosporidiosis in the colorectal cancer patients compared to the healthy subjects. The present descriptive case-control study was performed on 174 subjects including 87 healthy people and 87 patients with colorectal cancer attending to general hospitals in Lorestan Province, Western Iran, during October 2019–August 2020. A fresh stool specimen was collected from each subject in a sterile labeled container. The collected stool samples were concentrated using the sucrose flotation method and then prepared for Ziehl-Neelsen staining for microscopic examination. All samples were also tested using the Nested-PCR assays by amplifying the 18S rRNA gene for the presence of Cryptosporidium DNA. Demographic and possible risk factors such as age, gender, residence, agriculture activity, history of contact with livestock, consumption unwashed fruits/vegetables, and hand washing before eating were investigated in all the studied subjects using a questionnaire. Of the 87 patients with colorectal cancer, 37 (42.5%) had Cryptosporidium infection. A significant difference (p < 0.001) in the prevalence of Cryptosporidium spp. infections among the participants in the case and control (11, 12.6%) groups was observed. We found that cryptosporidiosis was not linked with age, gender, hand washing, agriculture activity, and history of contact with livestock in the colorectal patients. However, residence in urban areas was significantly associated with the prevalence of cryptosporidiosis. The 18 s rRNA gene of Cryptosporidium in 48 samples was successfully amplified by the Nested-PCR. Based on the obtained findings, Cryptosporidium spp. infections were observed significantly more frequently in the patients with colorectal cancer in comparison with the healthy individuals. It is suggested to carry out similar studies in various parts of Iran with larger sample sizes and further parasitological tests.