Typhus, infectious disease caused by rickettsia and carried by lice, leading to a feverish illness with a rash. Severe headache typically precedes the rash, which may progress to skin hemorrhage; mild respiratory symptoms of cough and breathlessness are common. Death ensues in a high proportion of untreated adults, usually with profound shock and kidney failure. Recurrences may occur in untreated patients who recover from their first attack, often after many years. A similar disease due to a different but related organism is carried by fleas (murine typhus). Chloramphenicol or tetracyclines provide suitable antibiotic therapy.