Tick bite fever has been a constant scenario in South Africa. Only recently has it been established that there are two aetiological
agents.
These two agents have different epidemiologies and clinical presentations. They are Ricketsia conorii and Rickettsia Africa.
Rickettsia Africa is the milder form of the disease. Rickettsia conorii can be fatal! The treatment of choice is doxycycline or
tetracycline. Macrolides and quinolones may be of value [1].
The earliest description of the disease resembling Meditteranean spotted fever or boutonneuse in southern Africa dates back to 1911.
The incubation period for R conorii is five to seven days. The eschar is the primary lesion and indicates the site of attachment of the
infected tick. It consists of a central necrotic area surrounding inflamed skin [2].
Clinical presentation may be mild to severe and includes encephalitis, confussion, coma, pulmonary embolism, bleeding,
myocarditis, hepatorenal failure and coagulopathy.
The diagnostic triad consists of eschar, fever and rash. The rash may resemble rubella, measles, secondary syphilis, enterovirus,
gonorrhoea, arbovirus, leptospirosis, drug reactios and immune complex disorders.
Serology is often negative and the Weil-Fellix agglutination test is obsolete. Specific microimmunofluorescence is the serological
method of choice. In complicated diseases neutropenia and thrombocytopenia may be noted, Most of the experience of steroids in
rickettsial disease may be extrapolated from their use in patients with complicated Rocky Mountain spotted fever [3].
In conclusion the diagnosis of the South African variety of Tick bite fever can be made if the classic triad of fever, eschar and rash
is present. Less typical forms of TBF present with a wide range of clinical features and severity. The treatment of choice is either
tetracycline or doxycycline [4].
References
1. Troup JM, Piper A. Tick bite fever in Southern Africa. Lancet. 1931; 2: 1183-6.
2. Miller GB, Gear JS. Treatment of tick bite fever with erythromycin. SA Med J; 1984; 66: 694-7.
3. Loubser MD, Davies VA, Meyers KE, Christianson AL. A severe Illness caused by ricketssia conorii. Ann Trop Paediatr.
1993; 13; 277-80.
4. Jensenius M, Fournier PE, Fladby T, Hellum KB, Hagen T, Priø T, Christiansen MS, et al. Sub-acute neuropathy in patients
with African tick bite fever. Scand J Infect., Dis. 2006; 38; 114-8.