First Detection of Mukawa Virus in Ixodes persulcatus and Haemaphysalis concinna in China

Abstract

Mukawa virus (MKWV), a novel tick-borne virus (TBV) of the genus <i>Phlebovirus</i> of family <i>Phenuiviridae</i>, has been firstly reported in <i>Ixodes persulcatus</i> in Japan. In this study, we made an epidemiological investigation in China to obtain the geographic distribution and genetic features of this virus outside Japan. We screened 1,815 adult ticks (665 <i>I. persulcatus</i>, 336 <i>Dermacentor silvarum</i>, 599 <i>Haemaphysalis longicornis</i>, 170 <i>Rhipicephalus microplus</i>, 45 <i>Haemaphysalis concinna</i>) and 805 wild small mammals collected from eight provinces. The positive rate of 6.77% (45/665, including 18 female and 27 male <i>I. persulcatus</i>) and 2.22% (1/45, 1 male <i>H. concinna</i>) were obtained from <i>I. persulcatus</i> and <i>H. concinna</i> in Heilongjiang province, respectively. No evidence of MKWV infection was found in other three tick species or any of the mammalian species. The virus can infect the Vero cells successfully, indicating the ability of MKWV to replicate in mammalian cells. A phylogenetic tree based on the nucleotide sequences of L, M, and S segments demonstrated that the Japanese MKWV variant, our two MKWV variants, and KURV were clustered with the members of the mosquito/sandfly-borne phleboviruses and distant from other tick-borne phenuiviruses. A phylogenetic analysis based on 895 bp partial L gene sequences (<i>n</i> = 46) showed that all MKWV sequences were separated into three lineages. Our results showed the presence of MKWV in <i>I. persulcatus</i> and <i>H. concinna</i> in northeast of China, highlighting the necessity of epidemiological study in wider regions. Due to the ability of MKWV to replicate in mammalian cells, the potential for zoonosis, and wide distribution of <i>I. persulcatus</i> and <i>H. concinna</i> in China, the important vectors of MKWV, further screening to more tick species, wild animals, domestic animals, and humans raises up practical significance.