Relapsing fever
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Relapsing fever is an infection caused by certain bacteria in the genus Borrelia.[1] It is a vector-borne disease that is transmitted through louse or soft-bodied tick bites.[2] It is not spread from animals or person-to-person. Tick-borne relapsing fever (TBRF) is found in Africa, Spain, Saudi Arabia, Asia, and certain areas in the western US and Canada. Louse-borne relapsing fever (LBRF) occurs in epidemics amid poor living conditions, famine and war in the developing world;[3] it is currently prevalent in Ethiopia and Sudan.
Most people who are infected get sick around 5-15 days after they are bitten by the tick. The symptoms may include a sudden fever, chills, headaches, and muscle or joint aches, and nausea; a rash may also occur. These symptoms continue for 2-9 days, then disappear. This cycle may continue for several weeks if the person is not treated.[4] Relapsing Fever is easily treated with 1-2 weeks of antibiotics. Most people improve within 24 hours of starting antibiotics. Complications and death due to relapsing fever are rare.
Relapsing fever is a candidate etiology for a mysterious series of plagues in late medieval and early renaissance-era England referred to at the time as sweating sickness but which have not recurred in epidemic form since the 16th Century.
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[edit] Louse-borne relapsing fever
Borrelia recurrentis is the only agent of louse-borne disease. Pediculus humanus, is the specific vector (P. pubis is not a vector). Louse-borne relapsing fever is more severe than the tick-borne variety.
Mortality rate is 1% with treatment; 30-70% without treatment. Poor prognostic signs include severe jaundice, severe change in mental status, severe bleeding, and prolonged QT interval on ECG.
Tetracycline is very effective, but may, within 2 hours, induce a Jarisch-Herxheimer reaction, which can be fatal. This reaction produces apprehension, diaphoresis, fever, tachycardia, and tachypnea with an initial pressor response followed rapidly by hypotension. Recent studies have shown that tumor necrosis factor (TNF) alpha may be partly responsible for the reaction.
[edit] See also
[edit] References
- ^ Schwan T (1996). "Ticks and Borrelia: model systems for investigating pathogen-arthropod interactions". Infect Agents Dis 5 (3): 167-81. PMID 8805079.
- ^ Schwan T, Piesman J (2002). "Vector interactions and molecular adaptations of lyme disease and relapsing fever spirochetes associated with transmission by ticks.". Emerg Infect Dis 8 (2): 115-21. PMID 11897061.
- ^ Cutler S (2006). "Possibilities for relapsing fever reemergence". Emerg Infect Dis 12 (3): 369-74. PMID 16704771.
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill, pp. 432&ndash4. ISBN 0838585299.
