Distribution and molecular characterization of rickettsiae in ticks in Harbin area of Northeastern China

PLoS Negl Trop Dis. 2020 Jun 4;14(6):e0008342. doi: 10.1371/journal.pntd.0008342. eCollection 2020 Jun.

Abstract

Tick-borne rickettsioses are world-spreading infectious zoonoses. Ticks serve as reservoirs and vectors for Rickettsia and play a key role in transmission of rickettsioses. Most of the Chinese rickettsiosis patients are reported from Northeastern China but the distribution of tick and tick-borne Rickettsia species in Northeastern China remain poorly studied. In this study, a total of 1,286 ticks were captured from the seven counties of Harbin, an area in Northeastern China, and the tick-borne Rickettsia species were identified by PCR and sequencing of rrs, gltA, groEL, ompA and 17-kDa antigen-encoding genes. Of the 5 identified tick species, Haemaphysalis longicornis and Ixodes persulcatus were the predominant tick species in the livestock and vegetation, respectively. Rickettsia raoultii and "Candidatus Rickettsia tarasevichiae" were the two detectable Rickettsia species in the ticks with a 28.8% positive rate but no rickettsiae were found in ticks of Haemaphysalis concinna. R. raoultii detected in 37.6% of the Dermacentor nuttalli, Dermacentor silvarum and H. longicornis ticks while "Ca. R. tarasevichiae" was only present in 22.8% of the I. persulcatus ticks. In particular, the positive rate of both R. raoultii and "Ca. R. tarasevichiae" in ticks from the livestock (40.7%) was significantly higher than that from the vegetation (19.5%). The results indicate that the tick and tick-borne Rickettsia species are diverse in different regions of Harbin due to geographic difference and the ticks from livestock may play a more important role in transmission of rickettsioses to human.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • China
  • Genes, Bacterial / genetics*
  • Humans
  • Ixodidae / microbiology
  • Phylogeny
  • Polymerase Chain Reaction
  • Rickettsia / classification*
  • Rickettsia / genetics*
  • Rickettsia Infections / microbiology
  • Sequence Analysis
  • Tick-Borne Diseases / microbiology
  • Ticks / microbiology*

Grants and funding

This work was supported by grants from Foshan University (KLPREAD201801-09 and KLPREAD201801-08), Education Bureau of Guangdong Province (2014KTSPT037 and 2018KQNCX277) and the Guangdong Provincial Science and Technology Plan (2012A020100001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.