1846 J. E. Worcester Pyrexical, relating to fever; febrile.
1876 E. Seguin i. xvii. 176 The incubation-period [of whooping-cough] is pyrexical, often hyperpyrexical.
1961 25 Mar. 637/2 During the past 2 years he has had pyrexical reactions to most, but not all, transfusions.
1999 T. McGowran iii. 64 Dengue fever, an influenza-like pyrexical illness.