| Parasite | Unindentified nematoda |
|---|---|
| Taxonomy | Nematoda |
| Host | Sea urchin (unidentified species) |
| Infection site | Unknown |
| Clinical sign | A filiform organism attaches on the sea urchin. |
| Parasitology | Only a cylindrical larva (length ca. 5 mm; width ca. 0.3 mm) was found (Fig. 1). A lip-like body at the anterior end (Fig. 2) and a blunt posterior end is observed (Fig. 3), but the structure is not clear. In Japan, nematodes of the genus Echinocephalus was reported in a sea urchin from Korea and U. S. A., this parasite is not the same species due to the morphological dissimilarity in the anterior end. It is suggested that this nematode is more similar to Echinomermella matsi, a nematode of sea urchin in Europe. |
| Pathology | No report. For E. matsi, it was reported that sexual maturation of the host might be impaired (Hagen, 1996). |
| Health hazard | Since this parasite is not infectious to human, it is harmless in food hygiene. |
| Diagnosis | Microscopic observation of cuticle-like structure around the worm suggested that this parasite is a member of nematode. |
| Other information | This parasite was found as a foreign matter attaching a live sea urchin. |
| References |
Hagen, N. T. (1996): Parasitic castration of the green echinoid Strongylocentrotus droebachiensis by the nematode endoparasite Echinomermella matsi: reduced reproductive potential and reproductive death. |
Fig. 1. A nematode from sea urchin.
Fig. 2. A head (above) and tail (below) of the worm.
(Photos by J. Araki)