- a recurrence;〔病気の〕a relapse
再発する ((病気・問題が主語)) recur, come back, flare up again;((人が主語)) have [suffer] a relapse
- がんが再発した
- He got cancer again./He had a recurrence of cancer.
- 結核が治ったと思ったら再発した
- We thought he had recovered from TB, but 「he had a relapse [it flared up again].