Chapter: Health Management in Aquaculture: Parasitic diseases and pests

Digenean Infestations - Fish Diseases Caused by Parasites

Digeneans are endoparasitic flatworms measuring 1-2.6 x 0.2-0.8 mm with 2 sucker-like attachment organs located at the anterior and ventral portions.

Digenean Infestations

Digeneans are endoparasitic flatworms measuring 1-2.6 x 0.2-0.8 mm with 2 sucker-like attachment organs located at the anterior and ventral portions (Fig. 5-7).

CAUSATIVE AGENTS:

Bucephalus, Lecithochirium, Pseudometadena, Transversotrema, Stellant-chasmus, Haplorchis, Procerovum, Prosorhynchus, Hemiurus

SPECIES AFFECTED:

Bighead carp, grass carp, milkfish, seabass, grouper, siganid, mullet

GROSS SIGNS:

Presence of small, white to yellow or brown to black cysts on the skin, fins, gills, muscle, stomach or intestine. Affected fish have distended abdomen. Growth retardation has been observed in some cases.

EFFECTS ON HOST:

Affects growth and survival or disfigures fish. Disrupts function of vital or-gans. It may cause mild diarrhea to cardiac and visceral complications in humans (definitive host).

DIAGNOSIS:

Gross and microscopic examinations of the gills, muscle and internal organs for opaque or creamy cysts containing motile metacercariae.

PREVENTION AND CONTROL:

Elimination of intermediate host

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Health Management in Aquaculture: Parasitic diseases and pests : Digenean Infestations - Fish Diseases Caused by Parasites |