Nematodes
Nematodes occur as adults and larvae in fish,
which may be definitive or intermediate hosts. 5,6
Most pathology is caused by migrating larval
forms, although emaciation and gastrointestinal
inflammation may result from adult enteric
forms. ~ Adult enteric forms include CapiUaria
spp. Larval forms include Contracaecum spp,
Eustrongyloides spp, and the well-known zoonotic
Anisakis spp. Definitive hosts for this group
include piscivorous birds and mammals. Enteric
nematodes may be effectively treated with benzimidazoles
or levamisole. There is no known
9 J effective treatment for m~gratlng or encysted
larval forms. These may be prevented by avoiding
feeding of aquatic insect larvae and freeliving
copepods that act as earlier intermediate
hosts. 6