Echinostoma revolutum

Name

Greek: stoma = mouth. Latin: echinatus = with spines; revolvere = turning around.

Geographic Distribution/Epidemiology

Worldwide, occasionally epidemics occur in mass animal farms.

Morphology/Life Cycle

The adults of trematode species Echinostoma revolutum reach a length of about 2 cm and are characterized by 37 spikes at their anterior bulbus. These flukes parasitize mainly in the ceca and in the rectum of water birds and produce 90–130 μm × 60–70 μm sized eggs (Fig. 1), which possess an operculum and which are found in the feces in an unembryonated stage (Echinostoma ilocanum; see Fig. 2). Inside the egg a miracidium larva is developed within 18–30 days if the eggs are laid into water. After hatching from the eggs the larvae penetrate into water snails (e.g., Lymnaea, Planorbis). The therein produced cercariae enter tadpoles, mussels, and snails and become finally transformed into metacercariae. If final hosts (inclusive humans) ingest such second intermediate hosts, adult worm...