Amphilochus

Amphilochus is a genus of parasitic flatworms belonging to the family Opisthorchiidae. These trematodes are endoparasites, meaning they live within the body of their host. The life cycle of Amphilochus species is complex, typically involving at least two intermediate hosts before reaching the definitive host, which is often a fish-eating mammal.

The first intermediate host is usually a freshwater snail. Within the snail, the parasite undergoes asexual reproduction, developing into a larval stage called a cercaria. These cercariae then emerge from the snail and infect the second intermediate host, which is a freshwater fish. In the fish, the cercariae encyst to form metacercariae.

When a definitive host consumes raw or undercooked infected fish, the metacercariae excyst in the digestive tract and mature into adult worms. Adult Amphilochus reside primarily in the bile ducts and gallbladder of their definitive hosts. Infections with Amphilochus can cause a condition known as amphilochiasis, which may lead to inflammation and damage of the bile ducts.

Several species are known, with Amphilochus vitalis being one of the more commonly studied. Distribution of Amphilochus species is generally confined to specific geographic regions, often linked to the presence of their required snail and fish intermediate hosts. While not as widely known as some other liver fluke infections, Amphilochus remains a concern in areas where its life cycle is prevalent and traditional consumption of raw fish occurs. Diagnosis often involves identifying the characteristic eggs of the parasite in stool samples.