We received a question from a curious woman who is wondering if there are worms that can live in our stomachs. We are sorry to tell her that there are, indeed, worms that can live in our stomachs. As always, we would like to remind our readers that we at All About Worms are not doctors. We never attempt to diagnose or treat any illness or parasitic infection. Anyone concerned about their health should visit a doctor.

It seems that our stomach’s acidic atmosphere would prevent worms from living there. However, nature is resourceful. If there is a place where food is available, it is likely that some sort of creature has evolved to live there. What better location than a stomach, where the food comes to you?

For example, there is the Anisakis worm. These are nematodes (round worms) which spend their lives in fish and marine mammals. When a human ingests undercooked seafood, they risk ingesting living Anisakis worms. Those worms may take up residence in the human’s esophagus, stomach, or intestines. This condition, called anisakiasis (or herring worm disease), cannot be passed from one human to another.

 

According to the Center for Disease Control (CDC):

The signs and symptoms of anisakiasis are abdominal pain, nausea, vomiting, abdominal distention, diarrhea, blood and mucus in stool, and mild fever. Allergic reactions with rash and itching, and infrequently, anaphylaxis, can also occur.

Once these creatures move in they are not easy to get rid of. In fact, removing the parasites may require surgery. Luckily, it is easy to avoid anisakiasis by simply not eating undercooked fish or squid. According to the same CDC FAQ, seafood should be cooked until its internal temperature is at least 145° F (~63° C).

The Guinea worm (Dracunculus medinensis) is another parasite that lives in the human stomach. Human infestation is called Dracunculiasis. Typically, we do not worry about Dracunculiasis in the US because it is contracted by drinking unsanitary water. The Clean Water Act introduced many safeguards to protect us from this type of problem.

There are many, many other types of parasitic worms that can live in the human body. Many of these can be avoided by not ingesting undercooked meat or seafood. In fact, figuring out what a patient has eaten is often a first step when parasites are suspected. So, if any of our readers think that they may have a parasite, they should let their doctors know what they have eaten recently.

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