also known as: blood fluke
Sanguinicola (blood fluke) has a 2-host life cycle, with an intermediate host snail or worm and a definitive host fish. Miracidia infect the snail, multiply within it and produce cercaria. The cercaria emerge and swim until they encounter the fish. in the fish they mature and produce eggs, which then hatch to form the miracidia, which then break out of the fish and swim to find the snail host. Adult flukes do not have any suckers or pharynx, and do not have the second intermediate host (bird) that other trematodes require.
The parasite can cause losses when infected fish reside in water containing large numbers of the snail intermediate host where the parasite can amplify rapidly. It can kill the fish if the blood system gets overloaded with developing eggs and miracidia. When the miracidia break out of the fish they can cause hemorrhaging and facilitate secondary infections of bacteria or fungi. Sanguinicola is not typically a problem in wild fish populations, but can cause issues in hatcheries if the hatchery water supply has high numbers of infected snails.
Examples of species:
Sanguinicola alseae in gill blood vessels of salmon, steelhead and rainbow trout OR-CA-ID-WA.
Sanguinicola klamathensis in heart of cutthroat trout, causes mortality during epizootics, OR, MT.