Effects on hosts Polymorphus spp. are parasites of seabirds, particularly the eider duck (Somateria mollissima). Heavy infections of up to 750 parasites per bird are common, causing ulceration to the gut, disease and seasonal mortality. Recent research has suggested that there is no evidence of pathogenicity of Polymorphus spp. to intermediate crab hosts. The cystacanth stage is long lived and probably remains infectious throughout the life of the crab.
Effects on hosts Polymorphus spp. are parasites of seabirds, particularly the eider duck (Somateria mollissima). Heavy infections of up to 750 parasites per bird are common, causing ulceration to the gut, disease and seasonal mortality. Recent research has suggested that there is no evidence of pathogenicity of Polymorphus spp to intermediate crab hosts. The cystacanth stage is long lived and probably remains infectious throughout the life of the crab.