A novel Rickettsia subspecies closely related to Rickettsia felis in Aedes albopictus from Qingdao City, Eastern China

Mosquitoes are generally regarded as the main vectors for many zoonotic diseases, capable of transmitting various diseases and causing significant public health burdens. In this study, a total of 232 Aedes albopictus mosquitoes were captured from Qingdao City, Shandong Province in the eastern part of China, and it was believed that a new subspecies of Rickettsia felis had been discovered. Genetic analysis indicated that the htrA gene has highest 99.29% identity to Rickettsia felis , an emerging human pathogen attracting global attention, predominantly sustained by fleas, mosquitoes and booklice. The 16S sequence of the strain had 100% of nucleotide similarity with Rickettsia sp. OnF11 gene for 16S rRNA . The gltA sequence had 98.77% similarity to both Candidatus Rickettsia senegalensis isolate and Candidatus Rickettsia senegalensis strain PU01-02. The groEL sequence had 99.42% similarity to Candidatus Rickettsia yingkouensis clone YK50. The ompB sequence had 99.42% similarity to Rickettsia hoogstraalii. In the phylogenetic tree based on concatenated nucleotide sequences of 16S , gltA , groEL , htrA and ompB genes, these strains were closely related to R. felis . Herein, it was named ‘Candidatus Rickettsia felis subsp. laoshanensis ’. Its ability to induce pathogenesis in both human and animal hosts is yet to be comprehensively determined.