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wildlife and zoo assay data sheet
Anisakid worms
Test code:
X0036
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Ultrasensitive qualitative detection of
Anisakis
and Pseudoterranova worms ("sushi worms")
by real time PCR.
Anisakiasis or herring worm disease is a parasitic disease caused by
infection with larvae of worms of the genera Anisakis and
Pseudoterranova. Anisakid worms share common features of
all nematodes, such as vermiform body plan, round cross section
and lack of segmentation. Currently, nine species are
genetically recognized in the genus Anisakis, and among
them Anisakis simplex and Anisakis pegreffii are
the major causes of human anisakiasis.
These worms, normally found in the flesh of many species of marine fish,
squid and other marine organisms, infect the gastrointestinal
tract of marine mammals like seals and toothed whales as part of
their life cycle, but can also be transmitted to humans.
Transmission occurs when a marine mammal or human eats raw or undercooked
fish or squid infected with anasakid larvae. People infected
with these worms typically develop abdominal pain, nausea, and
vomiting within hours of ingesting the larvae. If larvae
continue growing in the small intestine, it may result in an
inflammatory mass, and produce symptoms resembling Crohn’s
disease in one to two weeks. However, symptoms of anisakiasis
typically resolves spontaneously after several weeks; rarely, it
persists for months. Only in some cases is removal of the larvae
via endoscopy or surgery required. However, people who produce
immunoglobulin E in response to this parasite may subsequently
have an allergic reaction, sometimes including anaphylaxis,
after eating fish infected with Anasakis species.
Anisakiasis is more common in cultures where raw fish is often consumed,
such as Japan and Korea (as sashimi) and parts of Latin America
(as ceviche). However, due to internationalization of cuisines,
more and more people enjoy eating raw fish and squid; thus, the
incidence of human contact with these “sushi worms” is
increasing.
Anisakid worm larvae can survive pickling, salting, and smoking. If raw
fish consumption is desired, the fish can be frozen at -200C or below for 7 days before
consumption, as freezing can kill the larvae. However, fish
quality can be compromised by freezing, so if unfrozen fish is
desired for high-quality fresh sashimi or other raw dishes, the
source of the fish should be tested to screen for the presence
of anisakid larvae. Molecular detection by PCR is increasingly
being used to detect and confirm the presence of these worms in
fish and squid (Lim et al., 2015). PCR can also identify
nonviable larvae present in frozen fish.
Utilities:
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Help confirm and identify Anisakis
and Pseudoterranova
worms in fish or squid
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Screen fish or squid for parasites
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Shorten the time required to confirm a clinical diagnosis of the
infection
References:
Lim, H., Jung, B.-K., Cho, J., Yooyen, T., Shin, E.-H., & Chai, J.-Y.
(2015). Molecular Diagnosis of Cause of Anisakiasis in Humans,
South Korea. Emerging Infectious Diseases, 21(2), 342–344.
Specimen requirements:
Fresh, frozen or fixed worm or partial worm, or 0.2 ml fresh, frozen or
preserved fish flesh or squid flesh suspected of containing
larvae. Should there be a delay in shipping, refrigerate the
samples.
Contact Zoologix
if advice is needed to determine an appropriate specimen type
for a specific diagnostic application. For specimen
types not listed here, please contact Zoologix to confirm
specimen acceptability and shipping instructions.
For all
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
Turnaround time:
2 business days
Methodology:
Qualitative real time PCR
Normal range:
Nondetected
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