Wild Hedgehogs and Their Parasitic Ticks Coinfected with Multiple Tick-Borne Pathogens in Jiangsu Province, Eastern China

Abstract

The increasing awareness of emerging tickborne pathogens (TBPs) has inspired much research. In the present study, the coinfections of TBPs both in ticks and their wild hedgehog hosts in Jiangsu province, Eastern China were determined by metagenome next-generation sequencing and nested PCR. As a result, Rickettsia japonica (81.1%), novel Rickettsia sp. SFGR-1 (5.1%), Anaplasma bovis (12%), A. platys (6.3%), novel Ehrlichia spp. Ehr-1 (16%) and Ehr-2 (0.6%), E. ewingii-like strain (0.6%), Coxiella burnetii (10.9%), and a novel Coxiella-like endosymbiont (CLE) strain (61.1%) were detected in Haemaphysalis flava ticks. A. bovis (43.8%), Ehrlichia sp. Ehr-1 (83.3%), and C. burnetii (80%) were detected in Erinaceus amurensis hedgehogs. Coinfection rates with various TBPs were 71.5% and 83.3% in ticks and hedgehogs, respectively, both with double-pathogen/endosymbiont coinfection rates over 50%. We found the following. (i) Er. amurensis hedgehogs seem to contribute to the natural cycles of R. japonica, A. bovis, Ehrlichia sp., and C. burnetii and may be reservoirs of them except for R. japonica, and A. bovis is proved to infect hedgehogs for the first time. (ii) H. flava is proved to harbor various TBPs as a reservoir host, including CLE identified for the first time, which could inhibit coinfection of C. burnetii while promoting that of Rickettsia spp. in H. flava. (iii) Four novel TBP species were identified. This study provides useful epidemiological information crucial for assessing the potential infection risks to humans, thus benefiting the development of strategies to prevent and control tick-borne diseases. IMPORTANCE In the present study, we found the following. (i) Er. amurensis hedgehogs seem to contribute to the natural cycles of R. japonica, A. bovis, Ehrlichia sp., and C. burnetii and may be reservoirs of them except for R. japonica, and A. bovis is proved to infect hedgehogs for the first time. (ii) H. flava is proved to harbor various tickborne pathogens (TBPs) as a reservoir host, including Coxiella-like endosymbiont (CLE) identified for the first time, which could inhibit coinfection of C. burnetii while promoting that of Rickettsia spp. in H. flava. (iii) Four novel TBP species were identified. This study provides useful epidemiological information on TBPs harbored and transmitted by ticks and their hosts, for assessing the potential infection risks to humans, thus benefiting the developing strategies for tick-borne diseases prevention and control.

Keywords: Haemaphysalis flava; Rickettsia; coinfection; hedgehog; mNGS; tick; tick-borne pathogen.

FIG 1

Relative abundances of potential top 10 pathogens at the genus level in the pooled H. flava sample analyzed by metagenomic next-generation sequencing.

FIG 2

The observed positive rates and potential mutual communications of various pathogens in the H. flava ticks (n = 175) and Er. amurensis hedgehogs (n = 30). The identified Rickettsia spp. SFGR-1 and SFGR-2, Anaplasma spp. Ana-1 and Ana-2, Ehrlichia spp. Ehr-1, Ehr-2, and Ehr-3, and Coxiella spp. Cox-1 and Cox-2 in this study were indicated. The black forbidden symbol indicates the pathogens in H. flava didn’t spread to or establish infection in hedgehogs.

FIG 3

Positive rates of the tick-borne pathogens in different organs of the hedgehogs (n = 30).

FIG 4

Coexistences of various pathogens in H. flava ticks (A) and their Er. amurensis hedgehog hosts (B) at genus level. Pathogens and numbers of individuals harboring various pathogens are indicated.

FIG 5

Phylogenetic analysis based on the partial rrs gene sequence of Rickettsia (A) and Anaplasma (B) species using MEGA 7.0 software. Maximum likelihood method with 1,000 replicates was done to generate the tree. A bootstrap value of greater than 50% was indicated. Nucleotide substitutions per site are indicated by the scale bar. The reference species and GenBank accession number of the sequence are shown on each line.

FIG 6

Phylogenetic analysis based on the partial gene sequences of gltA of Ehrlichia species (A) and rrs of Coxiella species (B) using MEGA 7.0 software. Maximum likelihood method with 1,000 replicates was done to generate the tree. A bootstrap value of greater than 50% is indicated. Nucleotide substitutions per site are indicated by the scale bar. The reference species and GenBank accession number of the sequence are shown on each line.