A lobster sandwich is a beautiful thing until you find a tiny, thin worm in it, as a recent reader did who wrote to us via the All About Worms Facebook page. The reader purchased the thin worm-infused lobster sandwich at “a food fayre,” which we are assuming is a food fair that took place sometime in the 1800s for spelling-related reasons. After a few bites of the sandwich, the reader “saw a tiny (almost like a hair) sized worm that was striped black and white (ish) wriggling around on my lobster.” The reader said that it wasn’t a maggot, and again mentioned that the worm was “really thin like a piece of hair.” Naturally, the reader took the sandwich back, but was still worried about what she had found. What type of small, thin worms might be found in a piece of lobster?
Unfortunately, the reader wasn’t able to send a picture of the worm she found, which obviously makes identification more difficult. However, the reader’s physical description of the worm, particularly the fact that it is hair-like, suggests that she might have found a horsehair worm, which, as its name partially implies, looks like a hair from a horse’s tail. In fact, long ago it was believed that horsehair worms were literally horse hairs that somehow became alive.
We are fairly confident in this suggestion not only because horsehair worms are the only creatures we know of with such extraordinary body dimensions, but also because a lobster is the type of place one might find a horsehair worm. As we explain in our article about horsehair worms and their victims, these extremely thin parasitic worms generally take insects like grasshoppers and crickets as their hosts, but they also go after crustaceans, of which lobsters are an example. This is explained in greater depth in the article just linked to, but essentially horsehair worms select a host in which they can live and mature over the course of many weeks. After this period of maturation, the horsehair worm will exit its host, but only if there is water nearby. (This is why horsehair worms are often found in swimming pools.) Evidently, the horsehair worm inside the lobster our reader was eating (if it was a horsehair worm) never had the chance to abandon its host, so it was cooked right along with the lobster, although evidently not to the point of death since it was still moving when our reader found it.
So, our reader likely found a horsehair worm in her lobster sandwich, and while it was wise to take the sandwich back, it seems unlikely that the worms could cause any problems for our reader. For one, she apparently didn’t eat any of it, and even if she did, the cooking of the lobster meat could have killed anything harmful that was on the worm, even though the worm was still alive when it was found. (When we get questions about eating worms, which happens more than one might think, we generally make this point. Any given worm or larvae, simply by itself, probably isn’t harmful, but it could carry pathogens.) As always, though, we must point out that we can’t comment on any health related matters since we aren’t medical doctors. Therefore, if the reader does experience any problems associated with eating the lobster sandwich, she should seek medical care, even though we think it is unlikely that this will prove necessary.