Multispacer Sequence Typing Relapsing Fever Borreliae in Africa

In Africa, relapsing fevers are caused by four cultured species: Borrelia crocidurae, Borrelia duttonii, Borrelia hispanica and Borrelia recurrentis. These borreliae are transmitted by the bite of Ornithodoros soft ticks except for B. recurrentis which is transmitted by louse Pediculus humanus. They cause potentially undifferentiated fever infection and co-infection with malaria could also occur. The exact prevalence of each Borrelia is unknown and overlaps between B. duttonii and B. crocidurae have been reported. The lack of tools for genotyping these borreliae limits knowledge concerning their epidemiology. We developed multispacer sequence typing (MST) and applied it to blood specimens infected by B. recurrentis (30 specimens), B. duttonii (18 specimens) and B. crocidurae (13 specimens), delineating these 60 strains and the 3 type strains into 13 species-specific spacer types. B. crocidurae strains were classified into 8 spacer types, B. duttonii into 3 spacer types and B. recurrentis into 2 spacer types. These findings provide the proof-of-concept that that MST is a reliable tool for identification and genotyping relapsing fever borreliae in Africa

List of primers and genes flanking five intergenic spacers herein studied in relapsing fever <i>Borrelia</i>.

<p>Start and end of spacer are according <i>to B. duttonii</i> genome.</p

Distribution of spacers among the chromosome of <i>B. duttonii</i> and main differences within each spacer.

<p>Distribution of spacers among the chromosome of <i>B. duttonii</i> and main differences within each spacer.</p

List of spacer types (ST) found in this study.

<p>List of spacer types (ST) found in this study.</p

Pairwise comparison of each spacer of <i>B. duttonii, B. recurrentis</i> and <i>B. crocidurae</i>.

<p>Bold characters indicate range of similarity within the species.</p

Maximum-likelihood tree based on five intergenic spacers sequences for 61 <i>Borrelia</i> strains.

<p>To examine the confidence of ML tree, 100 bootstrap replicates were used.</p