Persistent fever with no apparent cause. The cause is usually an illness that is difficult to diagnose or a common disease that presents in an unusual way. These illnesses include various viral infections; tuberculosis; cancer, particularly lymphoma; and collagen diseases, such as systemic lupus erythematosus and temporal arteritis. Another possible cause is a drug reaction.... pyrexia of uncertain origin
a temperature of 38°C occurring on any 2 days within 14 days of childbirth or miscarriage. It is an indicator of postpartum *sepsis.... puerperal pyrexia