* Leeches (Hirudinea)
* Leeches are blood-sucking worms that can transmit diseases such as hirudiniasis, a skin infection caused by the bites of leeches.
* Leeches are also used in medicine to remove blood from patients who have been injured or have undergone surgery.
* Earthworms (Oligochaeta)
* Earthworms can transmit diseases such as acanthocephaliasis, a parasitic infection caused by the larvae of acanthocephalans, a type of roundworm.
* Earthworms are also used in medicine to produce castings, which are used to treat skin conditions such as eczema and psoriasis.
* Polychaetes (Polychaeta)
* Polychaetes are a class of marine worms that can transmit diseases such as polychaetosis, a skin infection caused by the bites of polychaetes.
* Polychaetes are also used in medicine to produce extracts that are used to treat conditions such as arthritis and cancer.