Molecular detection and characterization of Cryptosporidium spp. in the sewage-contaminated rivers entering Bandar-e Anzali Lagoon in Guilan Province, Iran

Waterborne cryptosporidiosis in river water is considered to be an important source of Cryptosporidium oocysts in most developing countries across the world. In the present study, 20 water samples were collected from Zarjoob and Goharrood rivers contaminated with wastewater in the province of Guilan, Iran. The samples were filtrated through a membrane filter (pore size: 1.2 μm), then the sucrose clarification and molecular genotyping methods were also carried out. In total, 12 out of 20 the samples were positive for Cryptosporidium species based on the 18S RNA-based polymerase chain reaction (PCR) and sequencing techniques. In addition, C. parvum, C. muris, C. homnis, and C. canis were detected in the samples studied. According to the results, the river water resources were polluted with the pathogenic species of Cryptosporidium with human and animal sources; this may result in an increase in the potential risk of waterborne cryptosporidiosis. Moreover, the long-term use of sewage-contaminated river water to irrigate crops and agriculture farms could be a major threat to local residents.