Emergence of a Novel Strain, Harboring the Major Immunogenic Glycoprotein trp36 with Unique Tandem Repeat and C-Terminal Region Sequences, in Haemaphysalis hystricis Ticks Removed from Free-Ranging Sheep in Hainan Province, China.

, a recently described species that is the most closely related to, but clearly distinct from, has been circulating in not only bovines, cervids, and dogs but also several tick species from Canada, Brazil, France, Pakistan, Ethiopia, and Israel. However, there are no reports of in China. The purpose of this study was to explore whether is present naturally in ticks in China. Through PCR targeting of the genus-conserved gene, DNA was detected in ticks removed from free-ranging sheep in Hainan Province, South China in 2017. The partial sequence of the , , and genes demonstrated that the Hainan strain shared 99% identity with the gene of strain UFMG-EV (GenBank: JX629808), with the of isolate E-2650 (MH500005) and with the gene of strain UFMG-EV (JX629806), respectively. Moreover, sequence analysis of the major immunogenic tandem repeat protein (trp36) revealed that the Hainan strain harbored a unique tandem repeat sequence (APEAAPVSAPEAAPVSAPVS) and a C-terminal region that differed from those of other known strains. Additionally, phylogenetic analysis based on the entire amino acid sequence of trp36 revealed that the Hainan strain was closely related to a recently described strain from Brazil, of which the sister clade contained different strains of . The discovery of this novel Hainan strain in ticks represents the first known natural presence of in South China, highlighting the need for its constant surveillance.