Monday, April 18, 2011

Case of the Week 157

The following worm was found in a frozen cod fillet from the local chain grocery store. When first received, it had a red-brown color and was in a tight coil. It measures approximately 3cm in length.(CLICK ON IMAGES TO ENLARGE)





Posterior end:




Most likely identification?

If ingested, would this worm cause infection?

7 comments:

Luke Roberts said...

An Anisakid nematode larvae - maybe Anisakis simplex or the cod/seal worm Pseudoterranova decipiens or Hysterothylacium aduncum?

all belong to the Anisakidae family. Freezing at -20 oC or below for 7 days or blast freezing at -35oC for 15 hours should kill the larvae, human anisakidiasis is a risk of eating raw or undercooked fish and can resut in abdominal pain, vomiting or worse. Even when frozen and killed/cooked, human pathology can result from toxins released by the parasite into the fish tissue.

Anonymous said...

An Anisakine larva. Fresh water varieties as well? I pulled a few similar larvae from smelt purchased at the grocery.

Anonymous said...

Given redish color and tight coiling, seems more likely Anisakis species. Freezing should render non-infectious, but I'll pass just the same.

Anonymous said...

Phocanema decipiens Cod worm

Anonymous said...

I have seen white string-like things that resemble thinner versions of the top picture. They extend through the meat. I have seen them in fresh water pickerel (caught myself), and salt water whitefish (bought from a farmer's market). I cook the food thoroughly and/or it is frozen prior to cooking, and usually don't notice them until eating the fish (I usually eat around them). Are they likely parasites, or something else?

Parasite Gal said...

Hi Anonymous,
All of the anisakid worms that I have seen in fish are in a tight coil like the one shown above. Take a look at case 140 for an example. If you are seeing white objects that aren't in coil, then I think you are probably seeing connective tissue fibers or blood vessels. Having said that, these worms are pretty common, so I would steer clear of anything you can't identify as being part of the fish!

Md Shohidul Islam Robin said...

Nice post. Check our fish display chiller