A Survey of the Larval Stages of Digenetic Trematodes in Freshwater Snails from the Al-Gharraf River, Northern Dhi Qar Province, Southern Iraq

This study investigated the occurrence and infection rates of digenetic trematode cercariae in freshwater snails from four sites along the Al-Gharraf River, north of Dhi Qar Province, southern Iraq, from July to December 2025. A total of 633 snails, belonging to two species of the genus Melanopsis (M. costata and M. buccinoides), were randomly collected and examined by direct crushing to detect larval stages. A total of 67 infected individuals were recorded, representing an overall infection rate of 10.58%. Infection was restricted to Melanopsis spp., indicating host specificity and ecological preference. Morphological examination revealed three distinct cercarial types: pleurolophocercous, furcocercous, and echinostomatid. These larval forms are associated with members of the families Heterophyidae, Cyathocotylidae, and Echinostomatidae. The findings provide baseline data on trematode–snail interactions in the Al-Gharraf River and highlight the ecological role of freshwater snails as intermediate hosts in parasite transmission.