Lewis & Short

febrīcŭla, ae, f. dim. [root bhā, to shine; cf. favilla], a slight fever (rare but class.): febriculam habere, Cic. Att. 6, 9, 1: in febriculam incidere, Planc. ap. Cic. Fam. 10, 21 fin.
In plur.: lentis febriculis diu detineri, Cels. 2, 17.