Molecular evidence of Anaplasma spp. in blood-sucking flies from China and identification of a putative novel Anaplasma species.

Tabanids and stomoxes are important mechanical vectors for the transmission of pathogens. Although the agents they transmitted have been well studied, bacteria of the genus Anaplasma harbored by these flies have never been reported in China. In this study, 262 blood-sucking flies (128 Stomoxys calcitrans, 45 Tabanus birmanicus, 69 Tabanus hypomacros, and 20 Tabanus taiwanus) were collected from the Wuhan and Nanping cities of China. Anaplasma marginale, Anaplasma bovis, and Candidatus Anaplasma cinensis are detected in S. calcitrans from Wuhan City, with positive rates of 15.63%, 1.56%, and 7.81%, respectively. Out of our expectations, a putative novel Anaplasma species was identified in all three tabanid species (40.00% in T. birmanicus, 15.94% in T. hypomacros, and 10.00% in T. taiwanus) from Nanping City. The 16 S rRNA and groEL gene sequences have highest 99.37-99.75% and 91.46% identities to A. marginale, while the gltA gene sequences have highest 88.34% identity to Anaplasma centrale. In the phylogenetic trees, these strains form a distinct clade. Herein we name it "Candidatus Anaplasma nanpingensis". The present study shows the existence of multiple Anaplasma species in blood-sucking flies in China. This may be the first report that blood-sucking flies harbor Anaplasma in China.