What is Tick-borne Relapsing Fever (TBRF)?
Relapsing fever is caused by spiral-shaped bacteria of the genus Borrelia and sub-species Relapsing Fever Borrelia (RFB). They are closely related to B. burgdorferi, the causative agent of Lyme disease. This group of bacteria is found world-wide and are transmitted by the body louse and ticks. Relapsing Fever can be divided into Louse-borne relapsing fever (LBRF), soft tick-borne relapsing fever and hard tick-borne relapsing fever.
Louse-borne relapsing fever is caused by a single Borrelia pathogen, B. recurrentis. The first case linked with spirochetal etiology and body louse transmission occurred in late 19th –early 20th century.
Soft tick-borne relapsing fever was first discovered to cause disease in humans in the early 20th century. The disease is caused by B. crocidurae, B. duttoni, B. persica, B. latyshervi, and B. hisponica, B. venezuelensis, B. mazotti, B. hermsii, B. turicatae, and B. parkeri.
Hard-tick relapsing fever infections are currently known to be caused by B. miyamotoi. B. miyamotoi was discovered in 2005 in Japan. In 2011, the first human case of B. miyamotoi infection was reported in Russia. In the US, the first case was reported in 2013.