In humans these can be divided into two groups: protozoa (all the single-celled parasites) and metazoa (multicellular parasites)
The common parasites are:
Protozoa
Metazoa
Nematodes (Roundworms)
Tissue nematodes:
Gut nematodes:
Cestodes (Tapeworms)
Trematodes (Flukes)
not an exhaustive list, of course.
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