A novel ehrlichial agent detected in tick in French Polynesia

Ticks are hematophageous arthropods that are known to host and transmit miscellaneous pathogens including zoonotic bacteria. The aim of this study was to investigate the presence of tick-associated microorganisms in Tahiti, French Polynesia with molecular tools. A total of 658 ticks from two species including Rhipicephalus sanguineus s.l. and Rh. annulatus were collected with forceps on dogs and cattle respectively, or with a flag on pasture in several locations of Tahiti in 2013. Two Rickettsia belonging to the spotted fever group different from R. conorii and R. massiliae were detected by qPCR in two Rh. sanguineus s.l. ticks, but sequencing failed. A Rh. annulatus tick was found positive for a new ehrlichial agent characterized by amplification and sequencing of fragments of the Anaplasmataceae 23S and Ehrlichia 16S genes. Phylogenetic analyses based on the 23S and 16S sequences reveals that this bacterium is a new genotype, genetically close to Ehrlichia minasensis, a recently described Ehrlichia sp. close to Ehrlichia canis.