Molecular Detection and Identification of “Candidatus Ehrlichia hainanensis”, A novel Ehrlichia Species in Rodents from Hainan Province, China

Abstract

Background: Ehrlichia is a genus of Rickettsiales bacteria closely related to human/animal disease and it plays an important role in public health. Naturally they are hosted by mammals such as canines, bovines, wild rodents and vectored by ticks. Results: In this study, we collected 121 rodent samples including 67 Niviventer fulvescens, 27 Rattus tanezumi, 24 Chiromyscus sp., 2 Rattus nitidus and 1 Leopoldamys edwardsi from Hainan province, which consists of the second largest island in China. The presence and genetic diversity of Ehrlichia was evaluated and characterized by amplifying and sequencing the 16S rRNA, groEL and gltA genes. An Ehrlichia was detected in 5 of the 67 Niviventer fulvescens samples (7.46%). The 16S rRNA, groEL and gltA genes show highest 99.20%, 89.87% and 83.86% identity to known Ehrlichia sequences. In the phylogenetic trees they form a distinct cluster from any other species.Conclusions: We propose that this Ehrlichia present a putative novel species nominated as ‘Candidatus Ehrlichia hainanensis’. Its pathogenicity to human is still to be further researched and molecular surveillance in local populations is needed.