Fascioloides magna
species of worm
Fascioloides magna, also known as giant liver fluke, large American liver fluke or deer fluke, is trematode parasite that occurs in wild and domestic ruminants in North America and Europe. Adult flukes occur in the liver of the definitive host and feed on blood. Mature flukes measure 4 to 10 centimetres (1+1⁄2 to 4 in) in length × 2 to 3.5 centimetres (3⁄4 to 1+3⁄8 in) in width, and have an oval dorso-ventrally flattened body with oral and ventral sucker. The flukes are reddish-brown in colour and are covered by tegument. As with other digenean trematodes, the life cycle includes intramolluscan phase in snails. The parasite is currently distributed in wild ruminants in North America and Europe, including Austria, Canada, the Czech Republic, Croatia, Germany, Hungary, Italy, Poland, Serbia, Slovakia, and the United States.
History
Fascioloides magna is essentially of North American origin but the parasite was introduced into Europe with imported game animals at the second half of the 19th century. In spite of being native to North America the fluke was first described in Italy. In 1875, Bassi observed massive deaths of red deer in the Royal Park (now La Mandria Regional Park) near Turin, Italy. The signs were similar to well known fasciolosis in sheep.
Begin with the source’s own compact description: “Fascioloides magna” is species of worm. The dossier treats that line as a proposition to test through Fascioloides, magna and species, not as a finished interpretation.
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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated May 23, 2026. The linked authority identifier is Q3376138. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1875.
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This entry incorporates text from “Fascioloides magna” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.