Molecular Detection and Characterization of Zoonotic and Veterinary Pathogens in Ticks from Northeastern China

Abstract

Tick-borne diseases are considered as emerging infectious diseases in humans and animals in China. In this study, <i>Ixodes persulcatus</i> (<i>n</i> = 1699), <i>Haemaphysalis concinna</i> (<i>n</i> = 412), <i>Haemaphysalis longicornis</i> (<i>n</i> = 390), <i>Dermacentor nuttalli</i> (<i>n</i> = 253), and <i>Dermacentor silvarum</i> (<i>n</i> = 204) ticks were collected by flagging from northeastern China, and detected for infection with <i>Anaplasma</i>, <i>Ehrlichia</i>, <i>Babesia</i>, and <i>Hepatozoon</i> spp. by using nested polymerase chain reaction assays and sequencing analysis. <i>Anaplasma phagocytophilum</i> was detected in all tick species, i.e., <i>I. persulcatus</i> (9.4%), <i>H. longicornis</i> (1.9%), <i>H. concinna</i> (6.5%), <i>D. nuttalli</i> (1.7%), and <i>D. silvarum</i> (2.3%); <i>Anaplasma bovis</i> was detected in <i>H. longicornis</i> (0.3%) and <i>H. concinna</i> (0.2%); <i>Ehrlichia muris</i> was detected in <i>I. persulcatus</i> (2.5%) and <i>H. concinna</i> (0.2%); <i>Candidatus</i> Neoehrlichia mikurensis was only detected in <i>I. persulcatus</i> (0.4%). The <i>Ehrlichia</i> variant (GenBank access number KU921424), closely related to <i>Ehrlichia ewingii</i>, was found in <i>H. longicornis</i> (0.8%) and <i>H. concinna</i> (0.2%). <i>I. persulcatus</i> was infected with <i>Babesia venatorum</i> (1.2%), <i>Babesia microti</i> (0.6%), and <i>Babesia divergens</i> (0.6%). Additionally, four <i>Babesia</i> sequence variants (GenBank access numbers 862303-862306) were detected in <i>I. persulcatus</i>, <i>H. longicornis</i>, and <i>H. concinna</i>, which belonged to the clusters formed by the parasites of dogs, sheep, and cattle (<i>B. gibsoni</i>, <i>B. motasi</i>, and <i>B. crassa</i>). Two <i>Hepatozoon</i> spp. (GenBank access numbers KX016028 and KX016029) associated with hepatozoonosis in Japanese martens were found in the collected ticks (0.1-3.1%). These findings showed the genetic variability of <i>Anaplasma</i>, <i>Ehrlichia</i>, <i>Babesia</i>, and <i>Hepatozoon</i> spp. circulating in ticks in northeastern China, highlighting the necessity for further research of these tick-associated pathogens and their role in human and animal diseases.