“I keep finding these black, thread-like worms in my bathtub”, states this reader about the multitude of minuscule worms pictured below next to the black insect. “And always in the poop of a dead ant or other dead bug that may have got in. I think they are sugar ants as they are very tiny. I put my cellphone camera in 4k video mode so I can use the light and zoom in. Then I took a screenshot to get the photo.” To start with, we want to thank our reader for putting in the effort to get such a good photo, as it always helps with the identification process: being able to see the organisms up close is always a big help.

Now, in terms of what species of ant this is, we are not entirely sure. Our best guess is that it is a black garden ant, which is one of the most commonly found species. These will usually be the ones roaming around on the grass outside in one’s yard. It could also be a sugar ant, though the most commonly found sugar ant has a brown stripe across its middle back, while the creature our reader found is a solid black color. In any case, the insect definitely looks like an ant, so we think our reader is correct in that. When it comes to what the worms are, there are a couple of possibilities we considered.

At first, we thought these might be drain fly larvae. Drain fly larvae are one of the worm-like organisms most commonly found in bathtubs and showers. They tend to show up when a bathroom has gone unused for quite some time, as the water will not have been run through the drains. The adult fly will lay eggs on the thin film that forms on the lip of the drain, and when the eggs hatch, the larvae will spread across the surface of the bathroom in search of food, which consists of decomposing organic matter (of which there is plenty in an unused bathroom).

However, there are two things that make us doubt that these are drain fly larvae: 1) The worms are too small. Drain fly larvae can actually reach the size of an adult black garden ant, so they would not be this much smaller in comparison. 2) Our reader stated that the worms were found in the faeces of the ant and other dead organisms. For that reason, we are more inclined to think that these worms may be parasites that came from the ant and the other dead insects. It is not entirely uncommon for ants to carry parasites, and it makes sense that this is what would have killed the ant and the other insects.

Now, the most common parasite to infect ants are tapeworms. The bad news is that they only use the ants as intermediate hosts before moving on to a primary host, which is usually a mammal, such as a human. With all of that said, we are not stating with any degree of certainty that these are tapeworms, or that these are even parasites that could infect humans. There are equally many species of parasites that only infect insects and not humans (and other mammals). If our reader has any concerns about herself with regard to parasites, she should consult a medical parasitologist. As we are not medical professionals, we are neither qualified nor legally able to identify such organisms, as making such an identification could be construed as a diagnosis.

To find a medical parasitologist, our reader can do one or more of the following:
1) Search for a medical parasitologist in their area using this directory of medical parasitology consultants: https://www.astmh.org/for-astmh-members/clinical-consultants-directory.
2) Search for a local parasitologist by doing a Google search for “medical parasitologist (name of the closest big city)” or “tropical medicine specialist (name of the closest big city)”.
3) Get in touch with Dr. Omar Amin at the Parasitology Center at https://www.parasitetesting.com.

In conclusion, we think that the worms our reader found are parasites that infected the ants (and other dead organisms) she found in her bathtub. It is not our place to say if these should be of concern to our reader, so if she wants to know that, she should consult a medical parasitologist and show them the same pictures, as well as give them the same context. We hope this article helps and we wish her the very best!

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