The history of epidemic typhus.

Few infectious diseases have influenced human civilization to the same degree as louse-transmitted typhus. Rickettsia prowazekii continues to strikes tens to hundreds of thousands of persons who live with war, famine, crowding, and in squalid conditions associated with social unrest, with mortality rates in excess of 10% to 15%. Historical documents confirm that such devastation has been a continuous feature of human existence to the extent that typhus has been a major determinant in the outcome of many wars, altering human history in its wake-despite incomplete knowledge of its precise origin. In the twenty-first century, circumstances are still conductive for outbreak; the emerging threat of bioterrorism raises justifiable concerns that typhus could affect civilization just as greatly in the future as it has in the past.