| Parasite | Acanthocolpidae digenean |
|---|---|
| Taxonomy | Plathyhelminthes, Trematoda, Opisthorchiida |
| Host | Japanes sea bass (Lateolabrax japonicus) |
| Disease name | Scoliosis |
| Infection site | Brain |
| Clinical sign | Diseased fish exhibits scoliosis (Fig. 1). A spherical yellow cyst is observed in the ventricle (Fig. 2). |
| Parasitology | This parasite was identified as Acanthocolpidae metacercaria (encysted larva of trematode) based on the morphology of the oral sucker and spines around the oral sucker. |
| Pathology | The scoliosis is considered to be caused by the metacercaria cyst in the brain because a vertebral fracture is not observed in the diseased fish. |
| Health hazard | Since this parasite is not infectious to human, it is harmless in food hygiene. |
| Diagnosis | Check the cyst and the morphology of the parasite in the ventricle. |
| Other information | In general, metacercariae of this family parasitize the muscle of marine fish. Thus, this case is possibly an accidental infection. |
| 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. Ctr.,
4, 143-161. (In Japanese) |
(Photos by K. Momoyama)
Fig. 1. Japanese sea bass exhibiting the scoliosis..
Fig. 2. Metacercaria cyst from the brain of deformed Japanese sea bass