Question: how do you know what type of parasite people have

Erin Pallott answered on 18 Mar 2024:

Parasitic diseases vary a lot. I work on parasitic worms that infected the gut, but there are others that infect other areas of the body. It was in the news recently that tapeworm larvae were found in a man’s brain in the US, which he caught from undercooked bacon.
https://www.bbc.co.uk/news/world-68566096

There are other types of parasites called protozoan parasites too, these are single-celled creatures, but not the same type as bacteria. These include Plasmodium which cause malaria and Trypanosoma brucei which causes sleeping sickness.

So there are specific methods to diagnose what type of parasite a person might be infected with. A simple test for gut worms would be looking for eggs in faeces samples. We can tell which one it is from the shape/features. For malaria and other blood-circulating parasites, a blood sample can be looked at under a microscope to look for the different stages of the parasite. Some other techniques might be needed such as X-rays and MRI scans to look for cysts and symptoms in other organs. Or maybe even cameras with endoscopies or colonoscopies to look for the parasites/symptoms within the gut.