Genomic characters of <i>Anaplasma bovis</i> and genetic diversity in China

The emergence of <i>Anaplasma bovis</i> or <i>A. bovis</i>-like infection in humans from China and the United States of America has raised concern about the public health importance of this pathogen. Although <i>A. bovis</i> has been detected in a wide range of ticks and mammals in the world, no genome of the pathogen is available up to now, which has prohibited us from better understanding the genetic basis for its pathogenicity. Here we describe an <i>A. bovis</i> genome from metagenomic sequencing of an infected goat in China. <i>Anaplasma bovis</i> had the smallest genome of the genus <i>Anaplasma</i>, and relatively lower GC content. Phylogenetic analysis of single-copy orthologue sequence showed that <i>A. bovis</i> was closely related to <i>A. platys</i> and <i>A. phagocytophilum</i>, but relatively far from intraerythrocytic <i>Anaplasma</i> species. <i>Anaplasma bovis</i> had 116 unique orthogroups and lacked 51 orthogroups in comparison to other <i>Anaplasma</i> species. The virulence factors of <i>A. bovis</i> were significantly less than those of <i>A. phagocytophilum</i>, suggesting less pathogenicity of <i>A. bovis</i>. When tested by specific PCR assays, <i>A. bovis</i> was detected in 23 of 29 goats, with an infection rate up to 79.3% (95% CI: 64.6% ∼94.1%). The phylogenetic analyses based on partial 16S rRNA, <i>gltA</i> and <i>groEL</i> genes indicated that <i>A. bovis</i> had high genetic diversity. The findings of this study lay a foundation for further understanding of the biological characteristics and genetic diversity of <i>A. bovis</i>, and will facilitate the formulation of prevention and control strategies.