The Ascocotylinae are a group of trematodes that is characterized by an elongation of the oral sucker (Figure 2-16). The genus Ascocotyle now contains worms that were previously included in the genera Phagicola, Leighia, and Parascocotyle. There are seven different species of Ascocotyle that have been reported from cats. All these trematodes gain access to cats through the ingestion of fish containing the metacercarial stage. It appears that many of these are parasites of other animals but that they are capable of developing in the cat if it happens to ingest the infected fish.

Figure 2-16.Ascocotyle chandleri from an experimentally infected cat that was fed killifish, Cyprinodonvariegatus, containing the metacercarial stage. Note the elongated oral sucker.