Echinostoma ilocanum

Name

Greek: echinos = hedgehog. Latin: stoma = mouth, spherical opening; canis = dog. English: spinal collar fluke.

Geographic Distribution/Epidemiology

In countries in Southeast Asia such as the Philippines, Japan, and India, several hundred thousand humans are infected (probably more, since symptoms are mostly low graded).

Morphology/Life Cycle

The trematode species Echinostoma ilocanum reaches a size of 7 × 1.5 mm and parasitizes in the small intestine of humans and of many mammals (e.g., dogs), but also enters the intestine of birds feeding mussels or snails. This species is characterized by an anterior collar, which bears 49–51 spikes (Figs. 1 and 2). Since these worms suck blood after they had destroyed blood vessels of the intestinal wall, they appear reddish. The excreted eggs are unembryonated, measure 90–115 × 60–70 μm, and are found in the feces of their hosts. The formation of the miracidium starts as soon as these eggs become covered by water. Finally the miracidium larva...