Relapsing fever

Relapsing fever
Specialty	Infectious diseases

Relapsing fever is a

Louse-borne relapsing fever occurs in epidemics amid poor living conditions, famine and war in the developing world.^[6] It is currently prevalent in Ethiopia and Sudan.^{[citation needed]}

Mortality rate is 1% with treatment and 30–70% without treatment. Poor prognostic signs include severe

Lice that feed on infected humans acquire the Borrelia organisms that then multiply in the gut of the louse. When an infected louse feeds on an uninfected human, the organism gains access when the victim crushes the louse or scratches the area where the louse is feeding. B. recurrentis infects the person via mucous membranes and then invades the bloodstream. No non-human, animal reservoir exists.^[citation needed]

Soft tick-borne relapsing fever

Tick-borne relapsing fever is found primarily in Africa, Spain, Saudi Arabia, Asia, and certain areas of Canada and the western United States. Other relapsing infections are acquired from other Borrelia species, which can be spread from rodents, and serve as a reservoir for the infection, by a tick vector.^{[citation needed]}

• Borrelia crocidurae – occurs in Egypt, Mali, Senegal, Tunisia; vectors – Carios erraticus, Ornithodoros sonrai; animal host – shrew (Crocidura stampflii
  )
• Borrelia duttoni, transmitted by the soft-bodied African tick Ornithodoros moubata, is responsible for the relapsing fever found in central, eastern, and southern Africa.
• Borrelia hermsii
• Borrelia hispanica
• Borrelia parkeri
• Borrelia turicatae
• Borrelia persica

B. hermsii and B. recurrentis cause very similar diseases. However, one or two relapses are common with the disease associated with B. hermsii, which is also the most common cause of relapsing disease in the United States. (Three or four relapses are common with the disease caused by B. recurrentis, which has longer febrile and afebrile intervals and a longer incubation period than B. hermsii.)^{[citation needed]}

Hard tick-borne relapsing fever

Borrelia miyamotoi, which is transmitted by Ixodes ticks, was reported as a cause of tick-borne relapsing fever in 2011.^[7][3]

Diagnosis

The diagnosis of relapsing fever can be made on blood smear as evidenced by the presence of spirochetes. Other spirochete illnesses (Lyme disease, syphilis, leptospirosis) do not show spirochetes on blood smear. Although considered the gold standard, this method lacks sensitivity and has been replaced by PCR in many settings.^[8]

Treatment

Relapsing fever is easily treated with a one- to two-week-course of

Relapsing fever has been described since the days of the ancient Greeks.[9] After an outbreak in Edinburgh in the 1840s, relapsing fever was given its name, but the etiology of the disease was not better understood for a decade.^[9] Physician David Livingstone is credited with the first account in 1857 of a malady associated with the bite of soft ticks in Angola and Mozambique.^[10] In 1873, Otto Obermeier first described the disease-causing ability and mechanisms of spirochetes, but was unable to reproduce the disease in inoculated test subjects and thereby unable to fulfill Koch's postulates.^[9] The disease was not successfully produced in an inoculated subject until 1874.^[9] In 1904 and 1905, a series of papers outlined the cause of relapsing fever and its relationship with ticks.^{[11][12][13][14]} Both

Sir William MacArthur suggested that relapsing fever was the cause of the yellow plague, variously called pestis flava, pestis ictericia, buidhe chonaill, or cron chonnaill, which struck early Medieval Britain and Ireland, and of epidemics which struck modern Ireland in the famine.[19]^[20] This is consistent with the description of the symptoms experienced by King Maelgwn of Gwynedd as recorded in words attributed to Taliesin and with the "great mortality in Britain" in 548 CE noted in the Annales Cambriae.^{[citation needed]}

See also

• Lyme disease
• Typhus
• Continuous fever
• Intermittent fever
• Remittent fever

References