A newly identified tick-borne Borrelia species and relapsing fever in Tanzania

Typing African Relapsing Fever Spirochetes

“…crocidurae ; and c) a further group containing unique amplicons from ticks collected in Tanzania. This last group was distinct in its IGS sequence and is likely compatible with the novel Borrelia species from this region ( 3 , 4 , 20 ). Three sequence types were identified that clustered within this novel IGS sequence clade, separate from the B .…”

“…hermsii and B . turicatae , rather than Old World tickborne relapsing fever and louseborne relapsing fever isolates ( 3 , 4 , 20 ). Insufficient material remained to allow repeat analysis for either flaB or rrs genes to confirm that Borrelia species types 1–3 were indeed the same spirochete described above.…”

“…However, this spirochete has an established reservoir in rodent populations that also serve as hosts for the Ornithodoros erraticus ticks. Recent reports have also established additional spirochetes in tick vectors ( 3 ) and in human blood samples ( 4 ); however, their clinical relevance has yet to be defined.…”

Possibilities for Relapsing Fever Reemergence

“…For these 2 spirochetes, whether the vector is also the reservoir (with the human's role being amplification of infected vectors) or if humans can be considered as the reservoir for infection is debatable. Recent work by Kisinza et al in the Dodoma region of Tanzania found 5% of febrile children had positive blood slides for Borrelia spp ( 22 ). Others studying nonfebrile persons have reported that 3% of them are spirochetemic by blood film examination.…”

“…in Africa that strongly resemble New World relapsing fever species suggests greater globalization of these spirochetes ( 22 – 24 ). As yet, the possible clinical importance of these spirochetes, for which the name " Candidatus Borrelia mvumii" has been proposed, remains unresolved ( 16 , 22 , 23 ). Studies are particularly hampered by the current lack of cultivatable strains.…”