Helminths From the Mallard (Anas Platyrhynchos) in the Netherlands

During the period September up to December 1969, 55 intestinal tracts of Anas platyrhynchos were examined for the presence of trematodes, cestodes and acanthocephalans. Nine species of trematodes, at least nine species of cestodes and two species of acanthocephalans were found. Of these, five trematode species and three cestode species are recorded in The Netherlands for the first time. The influence of migration of the host on the occurrence of the various groups and species of helminths is considered: the over-all prevalence, that of each group of helminths separately and the number of species per intestine showed a decrease as the number of winter resident hosts in samples did increase. Special attention was paid to the site of the helminth species in the intestine.