Emaciation as a Manifestation of Acanthocephaliasis in the Common Eider (Somateria mollissima)


  • Nadia Stegeman, DVM Texas A&M University
  • Emily Christiansen, DVM Ocean State Veterinary Specialists
  • Mark Pokras DVM Tufts Cummings School of Veterinary Medicine




Acanthocephalan, common eider, mortality events, emaciation


An annual die–off of juvenile common eiders (Somateria mollissima) occurs during late winter/early spring in coastal New England. Abnormally high mortality events, including significant numbers of adult birds, have occurred concurrently with die–offs of eiders’ primary food source, blue mussels (Mytilus edulis). In these situations, eiders are forced to switch to less preferred prey such as shore crabs (Carcinus and Hemigrapsus spp.). This species of shore crabs are a known intermediate host for acanthocephalan parasites (thorny–headed worms). Severe emaciation following infection with the acanthocephalan (Polymorphus botulus) is the common finding of an elevated mortality event in spring of 2006. This paper describes clinical presentations of eiders found during annual die–off periods and discusses possible treatment approaches identified in literature.


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Author Biographies

Nadia Stegeman, DVM, Texas A&M University

Nadia Stegeman is a graduate of Tufts DVM/MPH combined degree program and worked with the Seabird Ecological Assessment Network (SEANET) to investigate causes of mass mortalities on Cape Cod. She is currently a zoo medicine/surgery intern at Texas A&M University.

Emily Christiansen, DVM, Ocean State Veterinary Specialists

Emily Christiansen is a graduate of Tufts DVM/MPH combined degree program and worked with the Seabird Ecological Assessment Network (SEANET) to investigate causes of mass mortalities on Cape Cod. She is currently a small animal rotating intern at Ocean State Hospital in Rhode Island.

Mark Pokras DVM, Tufts Cummings School of Veterinary Medicine

Mark Pokras is the director of the wildlife clinic at Tufts University. He is heavily involved in conservation medicine and continues to inspire veterinary students to follow their hearts and strive to better our world.


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How to Cite

Stegeman, N., Christiansen, E., & Pokras, M. (2008). Emaciation as a Manifestation of Acanthocephaliasis in the Common Eider (Somateria mollissima). Wildlife Rehabilitation Bulletin, 26(2), 36–41. https://doi.org/10.53607/wrb.v26.152



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