AUTHOR=Lu Miao , Tian Junhua , Wang Wen , Zhao Hongqing , Jiang Hai , Han Jizhou , Guo Wenping , Li Kun 

TITLE=High diversity of Rickettsia spp., Anaplasma spp., and Ehrlichia spp. in ticks from Yunnan Province, Southwest China

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1008110

DOI=10.3389/fmicb.2022.1008110

ISSN=1664-302X

ABSTRACT=<p><italic>Rickettsia</italic>, <italic>Anaplasma</italic>, and <italic>Ehrlichia</italic> belonging to the order Rickettsiales are causative agents of tick-borne diseases in humans. During 2021, 434 ticks including <italic>Rhipicephalus microplus</italic> and <italic>R. haemaphysaloides</italic> were collected from three sampling sites in Yunnan Province, Southwest China, and analyzed for the presence of these bacteria. Nine bacterial species were identified, including two <italic>Rickettsia</italic> spp., three <italic>Anaplasma</italic> spp., and four <italic>Ehrlichia</italic> spp., some of which are potential human pathogens. Genetic and phylogenetic analysis on 16S rRNA, <italic>gltA</italic>, <italic>groEL</italic>, <italic>ompA</italic>, <italic>ompB</italic>, and <italic>sca4</italic> genes indicated the presence of a novel spotted fever group <italic>Rickettsia</italic> (SFGR) named “<italic>Candidatus Rickettsia</italic> shennongii” in six of the 38 <italic>R. haemaphysaloides</italic> ticks from two locations, Dehong Autonomous Prefecture and Honghe City. Another SFGR species, <italic>Candidatus Rickettsia</italic> jingxinensis was detected in ticks from all three sites, with an overall positive rate of 62.67%. Three other human pathogenic species, <italic>Anaplasma ovis</italic> (1.38%, 6/434)<italic>, Ehrlichia canis</italic> (16.36%, 71/434), and <italic>E. chaffeensis</italic> (0.23%, 1/434) were detected in these ticks and characterized. Moreover, <italic>Ehrlichia</italic> sp. (4.84%, 21/434), <italic>E. minasensis</italic> (7.37%, 32/434), <italic>A. marginale</italic> (6.91%, 30/434), and <italic>Cadidatus</italic> Anaplasma boleense (1.15%, 5/434) were detected in <italic>R. microplus</italic> ticks, for which pathogenicity to humans remains to be determined. The results reveal the remarkable diversity of Rickettsiales bacteria in ticks from Yunnan Province, Southwest China. The high infection rate of some human pathogenic bacteria in ticks may indicate potential infection risk in humans, and it highlights the need for surveillance in local populations.</p>