Animals Involved
Marine mammals (cetaceans and pinnipeds) and fish eating birds are definitive hosts; fish, crustaceans, and cephalopod mollusks are intermediate or paratenic hosts
Known Distributions
Worldwide but many cases in northern Asia and western Europe
Probable Means of Spreading
Ingestion of undercooked marine fish, squid, octopus
Clinical Manifestations in People
Gastroenteritis with upper quadrant pain; parasite usually in stomach; smallintestinal infections unusual but can occur; colon, esophagus rarely involved; oropharyngeal worm can cause hematemesis, cough; urticaria and other allergic signs after ingestion of live or dead worms