High diversity of Rickettsia spp., Anaplasma spp., and Ehrlichia spp. in ticks from Yunnan Province, Southwest China

Abstract

Rickettsia, Anaplasma, and Ehrlichia belonging to the order Rickettsiales are causative agents of tick-borne diseases in humans. During 2021, 434 ticks including Rhipicephalus microplus and R. haemaphysaloides were collected from three sampling sites in Yunnan Province, Southwest China, and analyzed for the presence of these bacteria. Nine bacterial species were identified, including two Rickettsia spp., three Anaplasma spp., and four Ehrlichia spp., some of which are potential human pathogens. Genetic and phylogenetic analysis on 16S rRNA, gltA, groEL, ompA, ompB, and sca4 genes indicated the presence of a novel spotted fever group Rickettsia (SFGR) named “Candidatus Rickettsia shennongii” in six of the 38 R. haemaphysaloides ticks from two locations, Dehong Autonomous Prefecture and Honghe City. Another SFGR species, Candidatus Rickettsia jingxinensis was detected in ticks from all three sites, with an overall positive rate of 62.67%. Three other human pathogenic species, Anaplasma ovis (1.38%, 6/434), Ehrlichia canis (16.36%, 71/434), and E. chaffeensis (0.23%, 1/434) were detected in these ticks and characterized. Moreover, Ehrlichia sp. (4.84%, 21/434), E. minasensis (7.37%, 32/434), A. marginale (6.91%, 30/434), and Cadidatus Anaplasma boleense (1.15%, 5/434) were detected in R. microplus ticks, for which pathogenicity to humans remains to be determined. The results reveal the remarkable diversity of Rickettsiales bacteria in ticks from Yunnan Province, Southwest China. The high infection rate of some human pathogenic bacteria in ticks may indicate potential infection risk in humans, and it highlights the need for surveillance in local populations.

Survey of Rickettsia species in hematophagous arthropods from endemic areas for Japanese spotted fever in China

“…Moreover, Candidatus Rickettsia jingxinensis, also named Candidatus Rickettsia longicornii ( Guo et al., 2019 ), was detected in H. longicornis and R. microplus ticks from Zigui County. This finding was not unexpected because it is a widely distributed spotted fever group Rickettsia species and has previously been detected in R. microplus and H. longicornis ticks from multiple provinces in China ( Guo et al., 2019 ; Wang et al., 2021 ; Lu et al., 2022 ). Additionally, two spotted fever group Rickettsia species— Ca.…”

“…It is surprising that Ca. Rickettsia jingxinensis, a spotted fever group Rickettsia frequently detected in ticks ( Guo et al., 2019 ; Wang et al., 2021 ; Lu et al., 2022 ), was identified in one C. tritaeniorhynchus sample. Natural infection of mosquitoes with Ca.…”

The Molecular Detection of Bacterial Infections of Public Health Importance in Hard Tick (Ixodidae) Nymphs Collected from the Forest Fringes of Western Ghats in the Goa, Karnataka and Maharashtra States of India

“…In the current study, Candidatus Rickettsia shennongii was identified in H. spinigera nymphs. This species was previously been reported as the causative agent of spotted fever in Rhipicephalus haemaphysaloides ticks in China [ 22 ]. Rickettsia spp.…”

Molecular surveillance reveals a potential hotspot of tick-borne disease in Hulunbuir City, Inner Mongolia

“…The Rickettsia and Anaplasmataceae were detected targeting the 16S rRNA gene, while Borrelia was screened targeting the aB ( agellin B) gene. For precise identi cation, the gltA and groEL (60 kDa chaperonin) sequences were ampli ed from the Rickettsia, Ehrlichia, and Anaplasma strains detected in this study using primers as shown [8,9]. Furthermore, 16S rRNA sequences (approximately 1200 bp) were ampli ed from the Borrelia strains [9], and gltA sequences (approximately 400 bp) were ampli ed from the Candidatus Lariskella strains [8].…”

“…The DNA samples were screened for the presence of Rickettsia, Anaplasmataceae (Anaplasma spp., Ehrlichia spp., etc), and Borrelia bacteria using primers as shown previously, generating PCR products with a size of approximately 900 bp, 450 bp, and 400 bp, respectively [8, 9,10]. The Rickettsia and Anaplasmataceae were detected targeting the 16S rRNA gene, while Borrelia was screened targeting the aB ( agellin B) gene.…”