Trematode infection among freshwater gastropods in Tessaout Amont irrigation system, Morocco

Abstract

In the summer of 1994 and the spring of 1995, a snail survey aimed at determining relationships between the distribution of molluscan fauna, various environmental factors and trematode infection was carried out in the Tessaout Amont irrigation system, Morocco. The molluscan fauna consisted of nine species belonging to seven families (including one bivalve). Cercariae belonging to nine families were collected. Ancylus fluviatilis and Mercuria confusa showed the highest prevalence of infection (1% and 2%, respectively) but were not listed among infected snails reported from other regions of the country. Melanopsis praemorsa and Bulinus truncates were shedding cercariae belonging to four and three families, respectively. Amphistome and echinostome cercariae were found for the first time in Morocco. No case of mixed-species infections was found.