Since the original description of the nematode genus Gnathostoma Owen, 1836 which was based upon material collected from a stomach nodule of a tiger that died after being imported into the London Zoological Garden, the endemic occurrence of members of the group has been observed principally in southern Asia, Africa, Philippines, Australia, China, and Japan. Species of the genus, either as larva or adult, parasitize a variety of hosts, including arthropods, fishes, amphibia, reptiles, birds, and mammals. Of the latter, such carnivores as Felidae, Canidae, and Mustelidae most often have been reported infected, although infrequent reports of infections in cattle, pigs, rodents, and man have appeared in the literature.