The parasite also known as the large American liver fluke is of the:

• A. Stephanurus species
• B. Fascioloides species
• C. Alaria species
• D. Metastrongylus species

Answer: (B)

Recognizing Fascioloides magna as the large American liver fluke helps you connect the common name to the place it lives and its biology. This trematode resides in the liver parenchyma of its definitive hosts and is a well-known fluke in North American wildlife and livestock. Its life cycle uses a freshwater snail as the first intermediate host, with a second host step before the final host ingests the parasite, leading to hepatic infection. This distinguishes it from other flukes listed: Stephanurus dentatus is a kidney worm of swine; Alaria species are intestinal flukes with different intermediate hosts and a different final site; Metastrongylus species are lungworms in pigs. Therefore, the large American liver fluke corresponds to Fascioloides magna.