Hemorrhagic lesions in stomach of rhesus monkey caused by a piscine ascaridoid nematode.

Within a few hours after being administered to the rhesus monkey (Macaca mulatta), Hysterothylacium type MB larvae penetrated the stomach wall, causing hemorrhage and attracting eosinophils. Inocula up to 300 larvae, however, did not cause peripheral hypereosinophilia. This species is the first ascaridoid which normally matures in fish that has been shown to penetrate the alimentary tract of a primate. Consequently, human consumption of raw seafood from at least the northern Gulf of Mexico free from infections, with Anisakis spp., Phocanema decipiens, or other species that mature in mammals or birds does not necessarily assure freedom from anisakiasis as previously assumed.