Nematode Parasitism of Oysters
Category 4 (Negligible Regulatory Significance in Canada)
Common, generally accepted names of the organism or disease agent
Nematode parasitism of oysters, Larval nematode infection.
Scientific name or taxonomic affiliation
a) Echinocephalus crassostreai (superfamily Spiruroidea, family Gnathostomidae).
b) Unidentified nematode.
a) Coast of Hong Kong and adjacent coast of The People's Republic of China.
b) Louisiana coast of U.S.A.
Impact on the host
The second- and third-stage larvae of E. crassostreai occurs primarily encysted in the gonad of C. gigas with minimal associated pathology. However, this nematode may cause gastric or other types of granulomatous lesions in humans if accidentally ingested.
Gross Observations: Larval nematodes (18 to 21 mm long) with a head-bulb holding 6 to 8 rows of hooks with 30-50 hooks per row.
Methods of control
No known methods of prevention or control. However, elasmobranch fish infected with the adult stage of this parasite must occur in the vicinity of the oysters in order to initiate the infection in oysters.
Cheng, T.C. 1978. Larval nematodes parasitic in shellfish. Marine Fisheries Review 40: 39-42.
Gauthier, J.D. and T.M. Soniat. 1988. A parasitological survey of oysters (Crassostrea virginica) along the Louisiana coast. Journal of Shellfish Research 7: 204-205. (Abstract).
Bower, S.M. (2001): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Nematode Parasitism of Oysters.
Date last revised: January 2001
Comments to Susan Bower
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