Microbiological Safety and Quality of Processed Shrimps and Fishes - Aquaculture Microbiology and Biotechnology - page 89

Table 4.7 Pathogenic parasites transmitted by fi sh and shellfi sh

Parasite Known geographical Fish and shellfi sh

distribution

Nematodes or round worms
Anisakis simplex

North Atlantic others herring sea-snails or

crustaceans

Pseudoterranova dicipiens North Atlantic and others Cod, almost all marine fi sh

Gnathostoma sp. Asia freshwater fi sh, frogs

Capillaria sp. Asia freshwater fi sh

Angiostrongylus sp. Asia, South America, Africa freshwater prawns, snails,

fi sh

Cestodes or tape worms
Diphllobothrium latum Northen hemisphere freshwater fi sh

D. pacifi cum Peru, Chile, Japan seawater fi sh

Trematodes or fl ukes
Clonorchis sp. Asia freshwater fi sh, snails

Opisthorchis sp. Asia freshwater fi sh

Metagonimus yokagawai Far East snails and freshwater fi sh

Heterophyes sp. Middle East, Far East snails, freshwater fi sh brackish

water fi sh

Paragonimus sp. Asia, America, Africa snails, crustaceans, fi shes

Echinostoma sp. Asia clams, freshwater fi shes,

snails

or more free-living stages may occur. Infection of humans may be part of
this life cycle or it may be a sidetrack causing disruption of the life cycle.

Nematodes
Round worms or nematodes are common and found in marine fi sh all over
the world. The anisakis nematodes A. simplex and P. dicipiens commonly
known as the herring worm and the cod worm have been intensively
studied (Healy and Juranek 1979 , Higashi, 1985; and Olson, 1987). They
are typical round worms, 1-6 cm long, and if humans ingest live worms,
they may penetrate into the wall of the gastrointestinal tract and cause an
acute infl ammation (“herring worm disease”).
A number of other nematodes are found in freshwater fi sh. Gnathostoma
sp. is the most important species found in Asia. The fi nal hosts are cats
and dogs but humans may be infected. Upon ingestion the larvae migrate
from the stomach to various regions, most commonly to subcutaneous
sites on the thorax, arms, head and neck, where the worms induce a
creeping sensation and edema (Huss, 1994).
Another nematode of public health importance is Capillaria sp. (e.g.,
Capillaria philippinensis ). The adult worms are gut parasites in piscivorous
birds and intermediate hosts are small freshwater fi sh. Infection in
humans cause severe diarrhea and possible death attributed to fl uid loss.