 A total of 51 species of parasitic worm have been recovered from the American white ibis , predominantly from the gastrointestinal system and particularly the small intestine . These include Cestoda ( tapeworms ) , Acanthocephala ( thorny headed worms ) , Nematoda ( roundworms ) , Digenea and Spirurida . Several roundworm and spirurid species have been found in the lining of the gizzard . Nematodes are more prevalent in American white ibis from freshwater habitats , and cestodes more frequent in those from saltwater areas . One nematode found in adult birds , Skrjabinoclavia thapari , is borne in the fiddler crab as an intermediate host , while the thorny headed worm species Southwellina dimorpha is carried in crayfish and infests both adult and juvenile ibis . 
