Tick- and louse-borne relapsing fever: Difference between revisions
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| − | + | *Infections caused by ''[[Borrelia]]'' spp. |
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| + | **'''[[Tick-borne relapsing fever]]''' (TBRF) is caused by non-Lyme ''Borrelia'' species |
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| + | **'''[[Louse-borne relapsing fever]]''' (LBRF) is caused by ''B. recurrentis'' |
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| + | {| class="wikitable" |
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| − | == Microbiology == |
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| + | !Species |
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| + | !Vector |
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| − | * '''Tick-borne relapsing fever (TBRF)''' is caused by multiple non-Lyme ''Borrelia'' species with global distribution |
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| + | !Distribution |
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| − | * '''Louse-borne relapsing fever (LBRF)''' is caused by '''''B. recurrentis''''' |
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| + | !Reservoir |
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| − | * Other non-Lyme ''Borrelia'' species include ''B. miyamotoi'' and ''B. lonestari'', although ''B. lonestari'' may also be able to cause TBRF |
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| − | * ''Borrelia'' are spirochetes |
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| − | * Serotypes are determined by the outer membrane variable major proteins (vmp) |
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| − | * Grow in modified Kelly medium and stained by Wright stain (in peripheral blood film) |
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| − | {| |
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| − | ! Species |
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| − | ! Vector |
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| − | ! Distribution |
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| − | ! Reservoir |
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| + | ! colspan="4" |Tick-borne relapsing fever (TBRF) |
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| − | | TBRF |
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+ | |''B. hermsii'' |
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+ | |''Ornithodoros hermsii'' |
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+ | |Western US and Canada (most common) |
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+ | |Rodent |
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+ | |''B. turicatae'' |
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+ | |''Ornithodoros turicata'' |
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+ | |Southwestern US |
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+ | |Rodent |
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+ | |''B. parkeri'' |
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+ | |''Ornithodoros parkeri'' |
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+ | |Western US and Baja California |
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+ | |Rodent |
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+ | |''B. mazzottii'' |
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+ | |''Ornithodoros talaje'' |
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+ | |Mexico and Central America |
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+ | |Rodent |
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| − | | |
+ | |''B. venezuelensis'' |
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+ | |''Ornithodoros rudis'' |
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+ | |South America |
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+ | |Rodent |
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+ | |''B. crocidurae'' |
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+ | |''Ornithodoros erraticus'' |
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+ | |Middle East |
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+ | |Rodent |
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+ | |''B. hispanica'' |
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+ | |''Ornithodoros marocanus'' |
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+ | |Iberian peninsula and North Africa |
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| + | ! colspan="4" |Louse-borne relapsing fever (LBRF) |
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| − | | LBRF |
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+ | |''[[Borrelia recurrentis|B. recurrentis]]'' |
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+ | |''Pediculus humanus'' |
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+ | |Ethiopia/Eastern Africa (previously worldwide) |
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| − | + | ! colspan="4" |Other |
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+ | |''B. miyamotoi'' |
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+ | |''Ixodes dammini'' and ''I. scapularis'' |
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+ | |US, Russia, and Japan |
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+ | |Deer |
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+ | |''B. lonestari'' |
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+ | |''Amblyomma americanum'' |
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+ | |Southern US |
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+ | |Deer & lizards |
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| + | [[Category:Borrelioses]] |
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| − | == Epidemiology == |
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| − | * TBRF is transmitted by ''Ornithodoros'' species ticks, with rodent reservoirs |
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| − | ** Present on every continent except Australia and Antarctica |
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| − | ** In North America, it is mostly in the Rocky Mountain regions above 1500 feet elevation |
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| − | *** Most have exposure to woodpiles or cabins with rodents |
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| − | ** Spirochetes can survive in the tick for years, and can be transmitted vertically within ticks |
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| − | *** Doesn't need its mammalian host to complete its life cycle |
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| − | ** Ticks feed for short periods (20 min) and are painless, so is often not noticed |
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| − | ** Can be transmitted vertically, by transfusion, and from laboratory exposure |
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| − | * LBRF was present nearly worldwide prior to World War II, but is now present in Ethiopia |
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| − | ** Associated with homelessness and refugee camps |
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| − | == Pathophysiology == |
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| − | * During febrile periods, spirochetes divide rapidly and cause a spirochetemia |
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| − | * This is followed by an immune response to the vmp proteins, which clears the spirochetemia and the patient becomes afebrile |
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| − | * The vmp proteins undergo rearrangement, evading the immune system and allowing another spirochetemia |
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| − | ** This is the cause of the relapsing fever |
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| − | == Clinical Presentation == |
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| − | * Incubation period of 7 days (range 2 to 18 days) |
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| − | * Relapsing fevers: febrile for 3 days, afebrile for 7 days |
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| − | * TBRF can relapse up to 30 times, whereas LBRF is usually self-limited after a single relapse |
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| − | ** Febrile periods may be associated with headache, myalgia, arthralgia, dizziness, and vomiting |
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| − | ** Each relapse is usually less severe |
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| − | * Some patients will have lymphadenopathy, hepatosplenomegaly, and a rash |
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| − | * Rare complications include lymphocytic meningitis, Bell palsy and other cranial nerve palsies, paralysis, seizure, uveitis, endophthalmitis, ARDS, and myocarditis |
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| − | * Can cause spontaneous abortion in pregnant women |
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| − | * May be septic, with multiple organ involvement |
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| − | * May have a Jarisch-Herxheimer reaction following empiric antibiotics |
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| − | == Differential Diagnosis == |
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| − | === Tick-borne relapsing fever === |
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| − | * Colorado tick fever (Coltivirus) |
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| − | * Brucellosis |
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| − | * Tularemia |
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| − | * Juvenile rheumatoid arthritis |
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| − | * Leptospirosis |
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| − | * Occult malignancy |
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| − | * Lyme disease |
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| − | === Louse-borne relapsing fever === |
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| − | * Typhus |
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| − | * '''Malaria''' |
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| − | * Typhoid fever |
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| − | * Leptospirosis |
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| − | * Hepatitis |
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| − | * Dengue |
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| − | == Diagnosis == |
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| − | * Often seen on blood film |
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| − | ** Giemsa or Wright stains |
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| − | ** 70% sensitive during febrile period for TBRF, lower for LBRF |
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| − | * Acute-convalescent serology with IFA/EIA |
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| − | ** May cross-react with Lyme disease |
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| − | * Can cause a false-positive VDRL |
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| − | * Can be cultured with modified Kelly medium |
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| − | == Management == |
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| − | === Tick-borne relapsing fever === |
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| − | * First-line: Doxycycline 100 mg po bid for 7 to 10 days |
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| − | * Alternatives: erythromycin 500 mg qid for 10 days |
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| − | * If CNS involvement: |
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| − | ** Penicillin G 3 mU IV q4h for 10-14 days, or |
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| − | ** Ceftriaxone 2 g IV q24h for 10-14 days |
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| − | |||
| − | === Louse-borne relapsing fever === |
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| − | * First-line: Doxycycline 200 mg po once |
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| − | * Alternatives: |
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| − | ** Penicillin G 400-800 kU IM once |
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| − | ** Erythromycin 500 mg po once |
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| − | == Prevention == |
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| − | * Can do post-exposure prophylaxis with doxycycline 200 mg po once followed by 100 mg daily for 4 days |
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Latest revision as of 19:51, 30 July 2020
- Infections caused by Borrelia spp.
- Tick-borne relapsing fever (TBRF) is caused by non-Lyme Borrelia species
- Louse-borne relapsing fever (LBRF) is caused by B. recurrentis
| Species | Vector | Distribution | Reservoir |
|---|---|---|---|
| Tick-borne relapsing fever (TBRF) | |||
| B. hermsii | Ornithodoros hermsii | Western US and Canada (most common) | Rodent |
| B. turicatae | Ornithodoros turicata | Southwestern US | Rodent |
| B. parkeri | Ornithodoros parkeri | Western US and Baja California | Rodent |
| B. mazzottii | Ornithodoros talaje | Mexico and Central America | Rodent |
| B. venezuelensis | Ornithodoros rudis | South America | Rodent |
| B. crocidurae | Ornithodoros erraticus | Middle East | Rodent |
| B. hispanica | Ornithodoros marocanus | Iberian peninsula and North Africa | |
| Louse-borne relapsing fever (LBRF) | |||
| B. recurrentis | Pediculus humanus | Ethiopia/Eastern Africa (previously worldwide) | |
| Other | |||
| B. miyamotoi | Ixodes dammini and I. scapularis | US, Russia, and Japan | Deer |
| B. lonestari | Amblyomma americanum | Southern US | Deer & lizards |
