This parasite is Zalophotrema hepaticum, a species of trematode or fluke. Pinnipeds obtain this parasite through the ingestion of infected fish. Although this species is usually confined to the liver, recent studies have found evidence of this trematode migrating to the brain of sea lions, laying eggs, and causing fatal brain damage.
Posted by Meaghan K.
Meaghan is a fall intern who is majoring in Marine and Freshwater Biology at Colgate University.
Fauquier, D., Gulland, F., Haulena, M., Dailey, M., Rietcheck, R. L., & Lipscomb, T. P. (2004). Meningoencephalitis in two stranded California sea lions (Zalophus californianus) caused by aberrant trematode migration. Journal of Wildlife Diseases, 40(4), 816-819.
Pérez Ponce de León, G. (1991). Hallazgo de Zalophotrema hepatícum (Trematoda: Campulidae), parásito del lobo marino Zalophus californianus. Anales del Instituto de Biología serie Zoología, 62(001).
Stroud, R. K., & Dailey, M. D. (1978). Parasites and associated pathology observed in pinnipeds stranded along the Oregon coast. Journal of Wildlife Diseases, 14(3), 292-298.