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Louse-borne Relapsing Fever - Coggle Diagram
Louse-borne Relapsing Fever
Epidemiology
Epidemic
Outbreaks during war/famine
Host: humans
Vector:
Pediculus humanus corporis
(human body louse)
Lice feed on infected humans
Acquire
Borrelia
Multiply in gut
Lice feed on uninfected human
Pathogenesis
Transmission
Spirochaetaemia
Borrelia present in blood during febrile illness
Disappears right before afebrile periods
Reappears in subsequent febrile periods
Borreliae hide in internal organsand re-emerge with modified antigens
New antigenic variant/serotype
As host responds to predominant serotype, a new serotype proliferates
Original serotype cleared by antibodies
Cyclic repetition causes relapse
Usually only one relapse
Incubation period: 4-18 days
Primary febrile illness lasts 3-6 days (terminates abruptly)
Symptoms recur in 7-10 days
Subsequent relapses tend to be less severe
Common causes of death
Myocarditis
Cerebral haemorrhage
Hepatic failure
Mortality
Untreated
10-40%
Treated
2-5%
Cause:
Borrelia recurrentis
Clinical Manifestations
Acute onset of high fever
Presents very similarly to Leptospirosis
Chills
Myalgia
Arthralgia
Severe headache
Lethargy
Cough
Confjunctival suffusion
Hepatosplenomegaly
Haemorrhage
Epistaxis
Haemoptysis
Haematuria
Neurological
Seizures
Meningitis
Cranial nerve palsies
Truncal rash
Diagnosis
*Demonstration of borreliae in peripheral blood
During febrile episodes
Smears stained by Giemsa or Wright stain
Culture possible on specific media
Serology not used for diagnosis
PCR in research setting
Treatment
Doxycycline
Tetracycline
Erythromycin
Penicillin G
Ceftriaxone
Single dose
