Gr. angeion = vessel, and strongylos = round

Angiostrongylus is a genus of parasitic nematodes (roundworms) in the family Angiostrongylidae, 2 species of which are known to parasitize humans. A. cantonensis (commonly known as ratlungworm) was first described in 1935 (as Pulmonema cantonensis) from rats in Canton, China. It is the most common cause of eosinophilic meningitis in Asia and the Pacific Basin, but cases have been reported in many parts of the world. A. costaricensis roundworms were first described in 1971 in Costa Rica from surgical specimens from children with eosinophilic infiltration in the abdominal cavity. The distribution of this species ranges from the southern United States to northern Argentina.

There is still debate about what taxonomic name should be used. A. cantonensis remains in general use, but some researchers suggest it should be changed to Parastrongylus cantonensis on the basis of the morphology of the adult male bursa and the definitive host being rats.