capillariasis /kap′ilərī′əsis/ , infection with nematodes of the genus Capillaria, species of which attack various different animals. Human infection is usually by C. philippinensis, which infests the intestines and causes severe diarrhea, malabsorption, and often death. More rarely, infection with C. hepatica can cause human hepatic capillariasis, and C. aerophila can cause human pulmonary capillariasis.