| Parasite | Unidentified trematoda |
|---|---|
| Taxonomy | Plathyhelminthes, Trematoda |
| Host | Ridged-eye flounder (Pleuronichthys cornutus) |
| Infection site | Subcutaneous tissue |
| Clinical sign | Bistered to brown cysts (1-2 mm) are observed in the blind side (Fig. 1). Many cysts are found in the fin. |
| Parasitology | Cyst includes a metacercaria (encysted larva) of trematode. The body of metacercaria is round and protrudes anteriorly. The stretching body is ca. 150 mm in length, while the shrinking body is ca. 100 mm (Momoyama and Tensha, 2006). |
| Pathology | No report. |
| Health hazard | Since this parasite is not infectious to human, it is harmless in food hygiene. |
| Diagnosis | Flatten the tissue around the cyst, and observe the parasite under the microscope. |
| Other information | Prevalence was low, while intensity was high (Momoyama and Tensha, 2006). |
| References | Momoyama, K. and K. Tensha (2006): Ugly-looking parasitic infections and
other abnormalities of wild fish and shellfish caught in the coastal or
inland waters around or in Yamaguchi Prefecture. Bull. Yamaguchi Pref. Fish. Res. Center.,
4, 143-161. (In Japanese) |
(Photos by K. Momoyama)
Fig. 1. A blind side of Ridged-eye flounder, parasitized by many trematode
Fig. 2. A metacercaria from the flounder.