[3] Outbreaks have been documented, for example, in Seattle[4] and Baltimore in the United States among injecting drug users[5] and in Marseille, France,[4] and Burundi.

The onset of symptoms is usually sudden, with high fever, severe headache, pain on moving the eyeballs, soreness of the muscles of the legs and back, and frequent hyperaesthesia of the shins.

[9] Trench fever episodes may involve loss of appetite, shin pain or tenderness, and spleen enlargement.

Bartonella quintana is transmitted by contamination of a skin abrasion or louse-bite wound with the faeces of an infected body louse (Pediculus humanus corporis).

The differential diagnosis includes typhus, ehrlichiosis, leptospirosis, Lyme disease, and virus-caused exanthema (measles or rubella).

Chloramphenicol is an alternative medication recommended under circumstances that render the use of tetracycline derivates undesirable, such as severe liver disease, kidney dysfunction, in children under nine years and in pregnant women.

The British Expeditionary Force Pyrexia of Unknown Origin Enquiry Sub-Committee concluded that the specific means by which the vector infected the host was louse waste entering the body through abraded skin.

Historically, trench fever was found in young male soldiers of World War I, whereas in the 21st century the disease mostly has a prevalence in middle-aged homeless men.

[20] Trench fever affected armies in Flanders, France, Poland, Galicia, Italy, Macedonia, Mesopotamia, Russia and Egypt in World War I.

Due in part to his findings, the louse was determined to be the primary cause of transmission by many, but this was still contested by multiple voices in the field such as John Muir who believed the disease was of a viral nature.

[24][25] It was not until the 1960s that J. Vinson demonstrated that Rickettsia quintana could be cultured extracellularly on blood agar and fulfilled Koch's postulates.

[23][24][27] During World War II, the British Government commissioned sheep dip manufacturer, Cooper, McDougall & Robertson of Berkhamsted, Herts to develop a product which troops could use to ward off lice.