Gnathostoma

Gnathostoma is a genus of parasitic nematodes with multi-host life-cycles. Successive hosts include copepods, fish and amphibians, and carnivorous and omnivorous mammals. Infection with nematodes of some Gnathostoma species causes gnathostomiasis in humans.

==Morphology== Nematodes of the genus Gnathostoma are characterized by a cephalic bulb, the head, which is covered by spines (often called hooks). The cephalic bulb is separated from the rest of the body by a constriction, the neck. There is a round oral cavity, or mouth, enclosed by two pseudolips. There are four cervical sacs inside the neck. (Richard Owen described long straight tubes equally spaced around the gastrointestinal tract and opening only into the mouth, calling them a "salivary apparatus".)