Anisakidae Railliet & Henry, 1912
- Nematode parasites of marine fish and marine
mammals, and occasionally responsinle for anisakiasis in humans....
Anisakid nematodes are common parasites of marine mammals, and have a
The nematodes of the family Anisakidae were probably first recognized
in fish hosts ine 13th century, in marine mammals in the early 1970s, as an
occasional human disease in 1867, and as a more common human infection in the
1950s and 1960s. Between 1970 and 1976, eight human cases of anisakiasis were
documented from North America (Myers, 1976).
Knowledge of nematodes responsible for human anisakiasis spans almost 500
years, paralleling advancement of research from visual observation-through
development of the microscope, electron microscope (Myers, 1976) and the
development of biolochemcal and molecular technology.
of the Anisakidae are a major problem for commercial fishing industries and are
potential human health hazards, both as causative agents of anisakiasis,
and as potential food-borne allergens (Nadler et al., 2005).
The following detailed descriptions and lifecycles of nematodes associased
with Anisakiasis are provided courtesy of CDC, the Centers for Disease Control
Anisakiasis is caused by the ingestion of larvae of several species of
ascaridoid nematodes (roundworms), which are sometimes called “herringworm”,
“codworm”, or “sealworm”, in undercooked marine fish. Known human-infecting
anisakid species include members of the Anisakis
simplex complex [A.
simplex sensu stricto, A.
pegreffii, A. berlandi (=A.
simplex C)], the Pseudoterranova
decipiens complex (P.
decipiens sensu stricto, P.
azarasi, P. cattani, and others), and the Contracecum
osculatum complex. Recent genetic studies have
revealed high diversity within these anisakid groups, suggesting additional
cryptic species are likely represented in zoonotic infections.
Adult stages of anisakid nematodes reside in the stomach of marine mammals,
where they are embedded in the mucosa in clusters. Unembryonated eggs produced
by adult females are passed in the feces of marine mammals .
The eggs become embryonated in water, undergoing two developmental molts ,
and hatch from the eggs as free-swimming ensheathed third-stage (L3) larvae .
These free-swimming larvae are then ingested by crustaceans .
The ingested larvae grow within the crustacean hemocoel, and become infective to
fish and cephalopod paratenic hosts. After preying upon infected crustaceans,
the digested L3 larvae migrate from the paratenic host intestine into the
abdominal cavity, and eventually to the tissues of the mesenteries and skeletal
muscle. Through predation, tissue-stage L3 larvae can be transmitted among
paratenic hosts .
Fish and squid maintain L3 larvae that are infective to humans and marine
When fish or squid containing third-stage larvae are ingested by definitive host
marine mammals, the larvae molt twice and develop into adult worms .
After ingestion by humans, the anisakid larvae penetrate the gastric and
intestinal mucosa, causing the symptoms of anisakiasis .
Gibson, D.I. 1983. Systematics of ascaridoid nematodes - a current
Concepts in nematode systematics : Proceedings of an international symposium
held jointly with the Association of Applied Biologists, in Cambridge / edited
by A.R. Stone, H.M. Platt, and L.F. Khalil
Myers, B.J. 1976. Research Then and Now on the Anisakidae Nematodes.
Transactions of the American Microscopical Society, 95:137-142.
Nadler, S.A. 1987. Biochemical and Immunological Systematics of Some
Ascaridoid Nematodes: Genetic Divergence between Congeners. The Journal of
Nadler, S.A., D'Amelio, S., Dailey, M.D. Paggi, L., Siu, S., Sakinari, J. A.
Molecular phylogenetics abnd diagnosis of Anisakis, Pseudoterranova, and
Contracaecum from Nothern Pacific marine mammals. J. Parasitol. 91:1413-1429.
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