''Centrocestus formosanus'' is a

trematode Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive h ...

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an are ...

n origin that has found its way into North American streams and rivers. It not only affects the

fountain darter The fountain darter (''Etheostoma fonticola'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in the h ...

but many species of commercially important fishes. It is also capable of infecting humans The parasite is transmitted via a freshwater snail Red-rimmed melania ''Melanoides tuberculata'' Vergara D. & Velásquez L. E. (2009). "LARVAS DE DIGENEA EN ''Melanoides tuberculata'' (GASTROPODA: THIARIDAE) EN MEDELLÍN, COLOMBIA. Larval stages of digenea from ''Melanoides tuberculata'' (Gastropoda: Thiaridae) in Medellín, Colombia". '' Acta Biológica Colombiana'' 14(1): 135-142
abstract

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. that was introduced in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

and

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

in the 1960s. The parasite is believed to have been introduced from shipments of

black carp The black carp (''Mylopharyngodon piceus'') or Chinese black roach is a species of cyprinid freshwater fish and the sole extant species of the genus ''Mylopharyngodon''. It is native to lakes and rivers in East Asia, ranging from the Amur Basin ...

to fish farms in Mexico. The definitive hosts of ''Centrocestus formosanus'' appear to be piscivorous birds that migrate along the central flyway from South America to North America.

References

Heterophyidae {{parasitic animal-stub