| Summary: | <p>Abstract</p> <p>Background</p> <p>To date, 6 tick-borne rickettsiae pathogenic for humans are known to occur in Africa and 4 of them were first identified in ticks before being recognized as human pathogens.</p> <p>Results</p> <p>We examined 33 and 5 <it>Amblyomma tholloni </it>ticks from African elephants in the Central African Republic and Gabon, respectively, by PCR amplification and sequencing of a part of <it>gltA </it>and <it>ompA </it>genes of the genus <it>Rickettsia</it>. The partial sequences of <it>gltA </it>and <it>ompA </it>genes detected in tick in Gabon had 99.1% similarity with those of <it>R. heilongjiangensis </it>and 97.1% with those of <it>Rickettsia </it>sp. HL-93 strain, respectively. The partial <it>gltA </it>and <it>ompA </it>gene sequences detected in tick in the Central African Republic were 98.9% and 95.1% similar to those of <it>Rickettsia </it>sp. DnS14 strain and <it>R. massiliae</it>, respectively. Phylogenetic analysis showed <it>Rickettsia </it>sp. detected in Gabon clusters with <it>R. japonica </it>and <it>R. heilongjiangensis </it>in a phylogenetic tree based on the partial <it>gltA </it>and <it>ompA </it>genes. The genotype of the <it>Rickettsia </it>sp. detected in the Central African Republic is close to those of <it>R. massiliae </it>group in the phylogenetic tree based on partial <it>gltA </it>gene sequences, and distantly related to other rickettsiae in the tree based on partial <it>ompA </it>gene.</p> <p>Conclusion</p> <p>The degrees of similarity of partial <it>gltA </it>and <it>ompA </it>genes with recognized species indicate the rickettsiae detected in this study may be new species although we could only study the partial sequences of 2 genes regarding the amount of DNA that was available. We propose the <it>Rickettsia </it>sp. detected in Gabon be provisionally named "<it>Rickettsia sp</it>. stain Davousti" and <it>Rickettsia </it>sp. detected in the Central African Republic be named "<it>Rickettsia sp. </it>strain Uilenbergi".</p>
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