Answer to Case 798

 Answer to the Parasite Case of the Week 798: Insect larva; specifically, a flea larva

As noted by Anatoly, this object has the features of a flea larva: "legless, segmented body (13), setae, head capsule, size". The location on the scalp is also supportive of a flea larva - likely from a household pet. Flea larvae are photophobic and are often found deep in animal and pet nests/bedding, carpets, and floor cracks. They are not parasitic on the host, and do not take a blood meal, unlike adult fleas. 

Some of you suggested that this could be myiasis, which is caused by dipteran fly larvae. However, fly larvae lack clear body segmentation as seen in this case, as well as a true head capsule and long bristles (setae). Although not shown in this case, flea larvae also lack spiracular plates as seen in dipteran larvae. 

In comparison to beetle larvae - another consideration in this case - flea larvae lack legs.

HERE is a nice resource from Animal Patient for additional information (and a rather disturbing video of flea larvae in carpet fibers 😯). The CDC has additional information on fleas, including the diseases that the adult fleas carry and how to get rid of them.

Here is a labelled diagram with some of the key diagnostic features seen in this case: 

Flea larvae range from 1 to 5 mm based on their instar stage.

Thanks again to Loranne Lambregts and Idzi Potters for donating this interesting case!