Metorchis conjunctus

Metorchis conjunctus, common name Canadian liver fluke, is a species of trematode parasite in the family Opisthorchiidae. It can infect mammals that eat raw fish in North America. The first intermediate host is a freshwater snail and the second is a freshwater fish. This species was discovered and described by Thomas Spencer Cobbold in 1860. The distribution of M. conjunctus includes: The body of M. conjunctus is pear-shaped and flat. The body length is 1⁄4–3⁄8 inch (6.4–9.5 mm). It has a weakly muscular terminal oral sucker. No prepharynx is present. The pharynx is strongly muscular. The esophagus is very short. The intestinal ceca vary from almost straight to sinuous. The acetabulum is slightly oval and weakly muscular. The male has an anterior testis and a posterior testis. The testes vary from almost round to oval, and may be deeply lobed or slightly indented. No cirrus pouch is found. The seminal vesicle is slender. The ovary is trilobed. The receptaculum seminis is elongated or pyriform, and slightly twisted, and situated to the right and behind the ovary. The eggs are oval and yellowish brown. The first intermediate host of M. conjunctus is a freshwater snail, Amnicola limosus. The second intermediate host is a freshwater fish: Catostomus catostomus, Salvelinus fontinalis, Perca flavescens, or Catostomus commersoni. Metacercaria of M. conjunctus were also found in northern pike (Esox lucius). The definitive hosts are fish-eating mammals such as domestic dogs (Canis lupus familiaris), domestic cats (Felis catus), wolves (Canis lupus), red foxes (Vulpes vulpes), gray foxes (Urocyon cinereoargenteus), coyotes (Canis latrans), raccoons (Procyon lotor), muskrats (Ondatra zibethicus), American minks (Neovison vision), fishers (Martes pennanti), or bears. It can also infect humans. It lives in the bile duct and in the gallbladder.