This document provides an overview of various febrile illnesses including typhus, typhoid fever, and relapsing fever. It discusses the etiology, transmission, pathogenesis, clinical presentation, treatment and prevention of these diseases. Key points include that typhus is caused by Rickettsia prowazekii and transmitted by human body lice, typhoid fever is caused by Salmonella typhi and transmitted through contaminated food/water, and relapsing fever involves recurrent fevers caused by Borrelia bacteria and transmitted by body lice or ticks. The document provides details on the symptoms, complications, diagnostics and management of these important infectious diseases.