The name Paragonimus is derived from the combination of two Greek words, “para” (on the side of) and “gonimos” (gonads or genitalia).

The first intermediate hosts of Paragonimus include at least 54 species of freshwater snails from superfamilies Cerithioidea and Rissooidea.

[4] Species of Paragonimus vary in size; the adult stage might attain a length of up to 15 millimetres (0.59 in) and a width of up to 8 mm (0.31 in).

[5] The adult flatworm has an oval shape body with spines covering its thick tegument.

The seminal receptacle, the uterus and its metraterm, the thick-walled terminal part, lie between the acetabulum and the ovary.

Humans usually contract paragonimiasis when they eat undercooked freshwater crabs (for instance species of the genus Nanhaipotamon) or crayfish, that contain live metacercariae.

[7] Paragonimiasis is caused by the body's natural immune response to the worms and eggs that are present and also migrating from the intestines to the lungs.

[citation needed] As a rule, the parasites begin to cause symptoms about three weeks after ingesting live metacercariae.