Gnathostoma spinigerum

Gnathostoma spinigerum is a parasitic nematode that causes gnathostomiasis in humans, also known as creeping eruption, larva migrans, Yangtze edema, Choko-Fuschu Tua chid and wandering swelling. Gnathostomiasis in animals can be serious, and even fatal. The first described case of gnathostomiasis was in a young tiger that died in the London Zoo in 1835. The larval nematode is acquired by eating raw or undercooked fish and meat.

G. spinigerum has a multi-host life history. The eggs hatch in fresh water and the larvae are eaten by water fleas of the genus Cyclops (genus)|Cyclops. The water fleas are in turn eaten by small fish. Eventually, the larvae end up in the stomachs of carnivores, usually cats and dogs. The larva bores through the stomach wall and migrates around in the host's body for about three months before returning to the stomach and attaching itself in the gastric mucosa. It then takes another six months to mature. The eggs are carried in the host's feces, and if they reach fresh water the cycle begins again. As humans are not a normal host for the larva, they do not mature in humans, but can cause various degrees of damage, depending on where the larve wanders in the body.