Ehrlichia, Coxiella and Bartonella infections in rodents from Guizhou Province, Southwest China

Prevalence, Species Characterization, and Genetic Diversity of Bartonella Infections in Rodents From Mudflat Wetlands Along the Eastern Coast of Jiangsu Province in China

Objective: To investigate the infection status, species composition, and genetic diversity of Bartonella in local rodent populations in coastal mudflat wetland habitats in eastern Jiangsu Province of China. Methods: From March to June 2023, rodents were captured in mudflat wetlands of Dongtai and Tinghu Counties, Eastern China. Rodent species were identified, and nucleic acids were extracted from liver and spleen tissues. The mitochondrial cytochrome b (mt-cytb) gene was amplified by PCR, while Bartonella-specific citrate synthase (gltA) and 16S rRNA genes were amplified by semi-nested PCR. Phylogenetic and homology analyses were conducted to identify rodent and Bartonella species. Results: Among 29 captured rodents, 26 were Apodemus agrarius and 3 were Mus musculus. Phylogenetic analysis of the mt-cytb gene divided A. agrarius into 7 lineages, each linked to geographically diverse Bartonella populations. Six A. agrarius rodents tested positive for Bartonella, with a positivity rate of 20.69%. Phylogenetic analyses revealed three Bartonella species: B. fuyuanensis, B. taylorii, and one undetermined species. The infected Bartonella strains clustered into three evolutionary branches based on gltA and 16S rRNA genes. Conclusions: This study provides the first evidence of Bartonella infection among rodent populations in wetland habitats along China's eastern coast. The region harbors diverse rodent species, with a high Bartonella infection rate, and at least three species were identified, including a potential novel species.

Tick-borne agents in the fowl tick Argas persicus from northwest and northeast China

Although tick-borne agents have been extensively studied, etiological investigations on soft ticks are still relatively rare. In this study, we collected 114 Argas persicus ticks from two provinces (Xinjiang and Heilongjiang) located in northwest and northeast China, respectively, and screened them for tick-borne agents. Two Rickettsia species were identified in A. persicus ticks from Heilongjiang Province: Rickettsia hoogstraalii (27.3%, 18/66) and a previously unidentified species (12.2%, 8/66). The 16S rDNA, gltA, groEL, and ompB genes of the latter have 98.8%, 93.1%, 94.3%, and 91.2% nucleotide identities to reported species, suggesting that it represents a novel species. It belongs to the ancient group of Rickettsia and is located in the basal position of the phylogenetic trees. Additionally, Coxiella endosymbiont was detected in A. persicus ticks from both locations with 100% positive rates. Furthermore, the Coxiella endosymbionts from different locations form distinct phylogenetic groups, indicating that one tick species can harbor different Coxiella endosymbionts.

Whole-genome analysis and antimicrobial resistance phenotype of Vagococcus fluvialis isolated from wild Niviventer

Vagococcus fluvialis (V. fluvialis), a Gram-positive bacterium belonging to the Enterococcaceae family, has been associated with human infections, including bacteremia and endocarditis. Its zoonotic potential raises concerns for public health, yet research on its antimicrobial resistance and pathogenicity is still limited. This study aimed to isolate and characterize V. fluvialis from wild Niviventer, analyze its genomic features (including antimicrobial resistance and virulence genes), and evaluate its antibiotic susceptibility profile to assess potential public health risks. We first isolated V. fluvialis (strain 25C42) from the rectum of wild Niviventer, confirmed through Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. Whole-genome sequencing (WGS) was performed using second-and third-generation technologies, with subsequent quality control and assembly. Six databases including KEGG, COG, CARD and VFDB were used for genome annotation. Antibiotic susceptibility was evaluated according to Clinical and Laboratory Standards Institute (CLSI) guidelines, determining the minimum inhibitory concentrations (MIC) for 16 antibiotics. Strain 25C42 was identified as V. fluvialis, confirmed by MALDI-TOF MS and 16S rRNA sequencing. WGS revealed a genome length of 2,720,341 bp, GC content of 32.57%. Functional genomic analysis identified 2,268 genes in the COG database and 2,023 genes in KEGG, highlighting key metabolic and cellular processes. Notably, 119 virulence genes and 65 antimicrobial resistance genes were found, indicating significant resistance potential. Phylogenetic analysis demonstrated a close relationship with other Vagococcus species, particularly V. fluvialis (ANI 98.57%, DDH 88.6%). Antibiotic susceptibility tests indicated strain 25C42 was resistant to clindamycin, tetracycline, rifampicin, cefoxitin and levofloxacin. Our findings reveal that the wild rodent-derived V. fluvialis strain 25C42 harbors clinically relevant antimicrobial resistance determinants and virulence-associated genes. The high genomic integrity and extensive functional gene annotation underscore its metabolic versatility. Notably, strain 25C42 exhibits significant antimicrobial resistance, necessitating ongoing surveillance and research to understand its implications for public health and environmental monitoring, as well as strategies for effective therapeutic intervention.

Genomic characterization and drug resistance of Bordetella pseudohinzii first isolated from wild niviventer

BACKGROUND

Niviventer, a rodent species widely distributed in Asian forests, serves as a significant reservoir for pathogens. Bordetella pseudohinzii(B. pseudohinzii), a recently identified Bordetella species with unclear pathogenic potential, poses challenges in species identification and understanding of its pathogenicity, its biological traits and antibiotic resistance are not well understood.

METHODS

B. pseudohinzii(strains 21F10, 22F12, and 27F25) were isolated from lung tissue of wild niviventer rodents in Guizhou, China. Initial identification was performed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS) and 16 S rRNA gene sequencing. A phylogenetic tree based on the 16 S rRNA gene sequences was constructed using the neighbor-joining method implemented in MEGA 11. Whole-genome sequencing (WGS) was conducted on all three strains, and strain 21F10 underwent hybrid assembly of second- and third-generation sequencing to achieve high-quality sequences. Average Nucleotide Identity (ANI) and digital DNA-DNA hybridization (dDDH) were used as gold standards for strain identification, with thresholds set at 95% and 70%, respectively. Gene annotation was performed using nine databases, including KEGG, VFDB, CARD, PHI, COG, and NR. Antimicrobial susceptibility testing was carried out using the drug-sensitive plate method.

RESULTS

Initial MALDI-TOF MS identification misclassified the strains as B. avium and B. hinzii. However, PCR amplification of the 16 S rRNA gene (primers 27 F and 1492R) revealed that the strains were identified as B. hinzii (identity > 99%). Further analysis of the 16 S rRNA gene sequences obtained from WGS showed identities greater than 99% with both B. pseudohinzii and B. hinzii. Phylogenetic analysis of the 16 S rRNA gene sequences showed that the strains were closely related to B. hinzii, followed by B. pseudohinzii. Ultimately, the ANI values of all three strains with B. pseudohinzii were greater than 95%, and dDDH values exceeded 70%, confirming the strains as B. pseudohinzii. Strain 21F10 exhibited notable findings in terms of virulence factors and antibiotic resistance genes. Antimicrobial susceptibility testing revealed significant resistance to several cephalosporins (cefoxitin, cefuroxime, cefotaxime, cefazolin, and ceftiofur). The 16 S rRNA and WGS of strain 21F10 have been deposited in GenBank and Genome Sequence Archive (GSA)under accession numbers PQ881859 and CRA022358, respectively.

CONCLUSION

The first isolation of B. pseudohinzii from the lung tissue of wild niviventer was reported, and the limitations of traditional methods for identifying B. pseudohinzii were demonstrated. We highlight the superiority of WGS for accurate species identification. The findings reveal a complex pathogenic profile and notable antibiotic resistance, providing important insights for the future prevention and treatment of B. pseudohinzii infections in humans, as well as underscoring the need for monitoring B. pseudohinzii in rodent populations.

Assessing the diversity of zoonotic bacterial agents in rodents and small mammals in Iran

The purpose of this study was to assess the prevalence of zoonotic bacteria, including Coxiella burnetii, Bartonella spp., Rickettsia spp., Brucella spp., Borrelia spp., and Ehrlichia spp., among small mammalian in Iran. We examined 618 small mammals collected between 2016 and 2020 from different parts of Iran. We extracted DNA from spleen samples and used quantitative real-time PCR to identify specific genes. We found 559 (90.45%) samples infected with at least one of the analyzed pathogens. Among the studied specimens, 86.08% tested positive for Bartonella spp., 2.42% for Ehrlichia spp., 0.80% for Borrelia spp., 0.64% for C. burnetii, 0.48% for Brucella spp., and 0% for Rickettsia spp. Bartonella krasnovii (25.81%) and Bartonella taylorii (25.81%) were the most prevalent among the Bartonella species. This study identified a rodent infected with Brucella abortus. Among the Borrelia-positive samples, four out of five were identified as Borrelia duttonii. Among the positive cases in the Ehrlichia genus, Ehrlichia canis, Candidatus Ehrlichia shimanensis, and Neoehrlichia mikurensis were identified. Meriones persicus was the most prevalent captured rodent with 315 specimens (51.22%). Our study revealed that a large proportion of the small mammals analyzed were infected with one or more of the targeted pathogens. M. persicus exhibited significant infection rates with C. burnetii, Bartonella spp., Ehrlichia spp., Brucella spp., and Borrelia spp. This suggests that this rodent species could serve as a crucial reservoir for zoonotic pathogens in Iran.

Different characteristics of the soil in marmot habitats might be one of the factors that influcting Yersinia pestis prevalent in which than pikas

Introduction

Marmots are recognized as host animals for plague caused by Yersinia pestis infection. It is unclear that why plague prevalent in marmot rather than other rodents like pikas in the same habitats. This study aims to analyze the differences of the soil characteristics around marmots and pikas burrows to explore the soils factors impacting on different epidemic intensities of Yersinia pestis in these two rodents.

Methods

Soil samples were collected from within and around marmot and pika burrows, as well as from the nearby areas not inhabited by them and Chinese baseline soil properties as control groups, in the Qilian Mountains of Gansu Province, China. The physicochemical properties and the bacterial 16S rRNA were measured to analyze the characteristics of soils from different groups. Subsequently, the data were analyzed using R studio.

Results

The analysis revealed that marmot habitats exhibited distinct soil characteristics, including lower organic matter and alkaline hydrolyzed nitrogen, but higher electrical conductivity and total soluble salts. And soil in marmot areas tended to have higher concentrations of nickel, chromium, and iron, also lower levels of zinc and selenium. Additionally, the alpha diversity of soil microorganisms in marmot habitats was significantly low. Simultaneously, redundancy analysis was conducted, which showed that the low alpha diversity of marmot-soil was influenced by its physicochemical properties. The alpha diversity of the soil was positively correlated with EC, TSS, Na, and Cr, etc., while it was negatively correlated with AHN, OM, Se, Zn, and Fe, etc.

Conclusion

These characteristics in marmot habitats, including low levels of organic matter, alkaline hydrolyzed nitrogen, zinc, selenium, and bacterial alpha diversity, as well as high levels of electrical conductivity, total soluble salts, iron, and nickel, played a crucial role in the spread of plague. It was discovered that the unique characteristics of marmot-soils provided essential elements necessary for the survival of Yersinia pestis, including high levels of Fe and Ca, or facilitated the spread of plague. Thus, the transmission of the plague was facilitated.

Prevalence and genetic diversity of rodent-associated Bartonella in Hulunbuir border regions, China

Bartonella spp. are globally distributed gram-negative facultative intracellular bacteria that infect a wide range of hosts. Rodents are natural reservoirs of many Bartonella species, some of which are also pathogenic to humans. The rapid development of transportation and tourism has highlighted the risk of Bartonella transmission to humans. Thus, it is essential to maintain surveillance of Bartonella spp. infections in rodents. In China, Bartonella spp. infections have been monitored in various areas; however, these have not included the Hulunbuir border regions. In the present study, we monitored the prevalence and genetics of rodent-associated Bartonella spp. in the Hulunbuir border regions. Eleven rodent species were captured at five ports. Eight species were confirmed as Bartonella-positive using quantitative PCR assay, with an overall positivity rate of 20.05 %. Lasiopodomys brandtii was the predominant rodent species captured for Bartonella detection. Sequencing and phylogenetic analysis (using the maximum likelihood method) revealed the presence of three Bartonella species in these rodents, including two pathogenic to humans, namely, Bartonella alsatica and Bartonella grahamii. B. grahamii was the predominant Bartonella species identified in the rodents. Taken together, these results highlight the prevalence and genetic diversity of Bartonella spp. in rodents in the Hulunbuir border regions, indicating the need for risk assessment of human spillover.

Molecular surveillance of zoonotic pathogens from wild rodents in the Republic of Korea

BACKGROUND

Rodents are recognized as major reservoirs of numerous zoonotic pathogens and are involved in the transmission and maintenance of infectious diseases. Furthermore, despite their importance, diseases transmitted by rodents have been neglected. To date, there have been limited epidemiological studies on rodents, and information regarding their involvement in infectious diseases in the Republic of Korea (ROK) is still scarce.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated rodent-borne pathogens using nested PCR/RT-PCR from 156 rodents including 151 Apodemus agrarius and 5 Rattus norvegicus from 27 regions in eight provinces across the ROK between March 2019 and November 2020. Spleen, kidney, and blood samples were used to detect Anaplasma phagocytophilum, Bartonella spp., Borrelia burgdorferi sensu lato group, Coxiella burnetii, Leptospira interrogans, and severe fever with thrombocytopenia syndrome virus (SFTSV). Of the 156 rodents, 73 (46.8%) were infected with Bartonella spp., 25 (16.0%) with C. burnetii, 24 (15.4%) with L. interrogans, 21 (13.5%) with A. phagocytophilum, 9 (5.8%) with SFTSV, and 5 (3.2%) with Borrelia afzelii. Co-infections with two and three pathogens were detected in 33 (21.1%) and 11 rodents (7.1%), respectively. A. phagocytophilum was detected in all regions, showing a widespread occurrence in the ROK. The infection rates of Bartonella spp. were 83.3% for B. grahamii and 16.7% for B. taylorii.

CONCLUSIONS/SIGNIFICANCE

To the best of our knowledge, this is the first report of C. burnetii and SFTSV infections in rodents in the ROK. This study also provides the first description of various rodent-borne pathogens through an extensive epidemiological survey in the ROK. These results suggest that rodents harbor various pathogens that pose a potential threat to public health in the ROK. Our findings provide useful information on the occurrence and distribution of zoonotic pathogens disseminated among rodents and emphasize the urgent need for rapid diagnosis, prevention, and control strategies for these zoonotic diseases.

Great genetic diversity of vector-borne bacteria and protozoan in wild rodents from Guangxi, China

BACKGROUND

Rodents are recognized as the hosts of many vector-borne bacteria and protozoan parasites and play an important role in their transmission and maintenance. Intensive studies have focused on their infections in vectors, especially in ticks, however, vector-borne bacterial and protozoan infections in rodents are poorly understood although human cases presenting with fever may due to their infection have been found.

METHODS

From May to October 2019, 192 wild rodents were trapped in wild environment of Guangxi Province, and the spleen samples were collected to reveal the presence of vector-borne bacterial and protozoan infections in them. The microorganisms in rodents were identified by detecting their DNA using (semi-)nested PCR. All the PCR products of the expected size were subjected to sequencing, and then analyzed by BLASTn. Furthermore, all the recovered sequences were subjected to nucleotide identity and phylogenetic analyses.

RESULTS

As a result, 192 rodents representing seven species were captured, and Bandicota indica were the dominant species, followed by Rattus andamanensis. Based on the (semi-)nested PCR, our results suggested that Anaplasma bovis, Anaplasma capra, Anaplasma ovis, Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis", "Candidatus E. hainanensis", "Candidatus E. zunyiensis", three uncultured Ehrlichia spp., Bartonella coopersplainsensis, Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella silvatica, two uncultured Bartonella spp., Babesia microti and diverse Hepatozoon were identified in six rodent species. More importantly, six species (including two Anaplasma, two Bartonella, "Ca. N. mikurensis" and Bab. microti) are zoonotic pathogens except Anaplasma bovis and Anaplasma ovis with zoonotic potential. Furthermore, dual infection was observed between different microorganisms, and the most common type of co-infection is between "Ca. N. mikurensis" and other microorganisms. Additionally, potential novel Bartonella species and Hepatozoon species demonstrated the presence of more diverse rodent-associated Bartonella and Hepatozoon.

CONCLUSIONS

The results in this work indicated great genetic diversity of vector-borne infections in wild rodents, and highlighted the potential risk of human pathogens transmitted from rodents to humans through vectors.

Investigation of tick-borne bacterial microorganisms in Haemaphysalis ticks from Hebei, Shandong, and Qinghai provinces, China

Tick-borne microorganisms in many tick species and many areas of China are still not thoroughly investigated. In this study, 224 ticks including two species (Haemaphysalis longicornis and Haemaphysalis qinghaiensis) were collected from four cities in Hebei, Shandong, and Qinghai provinces, China. Ticks were screened for the presence of tick-borne bacterial microorganisms including Rickettsia, Anaplasmataceae (Anaplasma, Ehrlichia, Neoehrlichia, etc.), Coxiella, Borrelia, and Bartonella. Two Anaplasma species (Anaplasma ovis and Anaplasma capra) were detected in H. longicornis from Xingtai City of Hebei Province, with a positive rate of 3 % and 8 %, respectively. A Coxiella species was detected in H. longicornis ticks from all three locations in Hebei and Shandong provinces, with the positive rate ranging from 30 to 75 %. All the 16S and rpoB sequences were very similar (99.77-100 % identity) to Coxiella endosymbiont of Haemaphysalis ticks. An Ehrlichia species was detected in H. qinghaiensis (6/66, 9 %) from Xining City, Qinghai Province. The 16S and groEL sequences had 100 % and 97.40-97.85 % nucleotide identities to "Candidatus Ehrlichia pampeana" strains, respectively, suggesting that it may be a variant of "Candidatus Ehrlichia pampeana". All the ticks were negative for Rickettsia, Borrelia, and Bartonella. Because all the ticks were removed from goats or humans and were partially or fully engorged, it is possible that the microorganisms were from the blood meal but not vectored by the ticks. Our results may provide some information on the diversity and distribution of tick-borne pathogens in China.

Infections and Influencing Factors of Pathogens in Rattus norvegicus along the Zengjiang River in Guangzhou, China

Background: Rattus norvegicus can carry and transmit various zoonotic pathogens. Some studies were conducted to investigate a few zoonotic pathogens in Guangzhou, China, but no coinfections were investigated or specifically mentioned. Studies on the infections and the influencing factors of various zoonotic pathogens in R. norvegicus along the Zengjiang River in Guangzhou have not been carried out. Materials and Methods: In this study, R. norvegicus was captured in November 2020 and September 2021 along the Zengjiang River, and was tested for Bartonella spp., Leptospira spp., Orientia tsutsugamushi, Borrelia burgdorferi, Hantavirus (HV), Ehrlichia spp., and severe fever with thrombocytopenia syndrome virus (SFTSV) by the RT-PCR. Logistic regression analysis was used to determine the impact of habitat and demographic factors on the infections and coinfections of the surveyed pathogens. Results: In 119 R. norvegicus, the detection rates of Bartonella spp., Leptospira spp., O. tsutsugamushi, B. burgdorferi, and HV were 46.2%, 31.9%, 5%, 0.8%, and 18.5%, respectively. Ehrlichia spp. and SFTSV were negative. The triple coinfection rate of Bartonella spp., Leptospira spp., and HV was 11.8%. In addition, the coinfection of Bartonella spp., Leptospira spp., and B. burgdorferi was 0.8%. Dual coinfection of Bartonella spp. and Leptospira spp., Leptospira spp. and HV, Bartonella spp. and O. tsutsugamushi, Leptospira spp. and O. tsutsugamushi, and HV and O. tsutsugamushi was 9.2%, 3.4%, 1.7%, 1.7%, and 0.8%, respectively. Infections of these pathogens in R. norvegicus were found in habitats of banana plantation, grassland, and bush. Weight affected the infection of Bartonella spp., Leptospira spp., or HV in R. norvegicus. Conclusions: R. norvegicus along the Zengjiang River not only carried various potentially zoonotic pathogens but also had a variety of coinfections. Surveillance of the density and pathogens in R. norvegicus should be strengthened to reduce the incidence of relevant zoonotic diseases.

Circulation of multiple Rickettsiales bacteria in ticks from Sichuan province, Southwest China

During 2021, 403 ticks including Haemaphysalis qinghaiensis, Ixodes ovatus, Ixodes acutitarsus, and Rhipicephalus microplus were collected from three sites (590, 310, and 576 km away from each other) in Sichuan Province, China. A total of nine Rickettsiales species were identified in them, including three Rickettsia spp., five Anaplasma spp., and one Ehrlichia sp. Anaplasma ovis and a novel Rickettsia sp. named "Candidatus Rickettsia liangshanensis" were characterized in I. ovatus ticks from Liangshan, with positive rates of 11.11% and 45.56%, respectively. Anaplasma capra (13.33%) and Anaplasma bovis (15.33%) were detected in H. qinghaiensis ticks from Maerkang. Phylogenetic analysis based on 16S rRNA, gltA, and groEL gene sequences indicated that the A. bovis strains were divided into two groups. Additionally, a novel Ehrlichia species named "Candidatus Ehrlichia maerkangensis" was identified. It is closely related to "Candidatus Ehrlichia zunyiensis" which was previously reported in Berylmys bowersi rats from Zunyi City, Southwest China. In R. microplus from Mianyang, "Candidatus Rickettsia jingxinensis" was detected with a high prevalence (92.99%). Notably, a variant of R. raoultii was identified in I. acutitarsus (33.33%). This may be the first Rickettsiales bacterium reported in I. acutitarsus. Our results reveal the remarkable biodiversity of Rickettsiales in this area. Some of these bacteria are human pathogens, indicating the potential exposure risk to local people.

Zoonotic pathogens identified in rodents and shrews from four provinces, China, 2015-2022

Rodents and shrews are major reservoirs of various pathogens that are related to zoonotic infectious diseases. The purpose of this study was to investigate co-infections of zoonotic pathogens in rodents and shrews trapped in four provinces of China. We sampled different rodent and shrew communities within and around human settlements in four provinces of China and characterised several important zoonotic viral, bacterial, and parasitic pathogens by PCR methods and phylogenetic analysis. A total of 864 rodents and shrews belonging to 24 and 13 species from RODENTIA and EULIPOTYPHLA orders were captured, respectively. For viral pathogens, two species of hantavirus (Hantaan orthohantavirus and Caobang orthohantavirus) were identified in 3.47% of rodents and shrews. The overall prevalence of Bartonella spp., Anaplasmataceae, Babesia spp., Leptospira spp., Spotted fever group Rickettsiae, Borrelia spp., and Coxiella burnetii were 31.25%, 8.91%, 4.17%, 3.94%, 3.59%, 3.47%, and 0.58%, respectively. Furthermore, the highest co-infection status of three pathogens was observed among Bartonella spp., Leptospira spp., and Anaplasmataceae with a co-infection rate of 0.46%. Our results suggested that species distribution and co-infections of zoonotic pathogens were prevalent in rodents and shrews, highlighting the necessity of active surveillance for zoonotic pathogens in wild mammals in wider regions.

Detection of Bartonella in kissing bugs Triatoma rubrofasciata collected from Huizhou City, South China

Background

The blood-feeding behavior of kissing bugs (subfamily Triatominae, family Reduviidae, order Hemiptera) means they are potential vectors of multiple humans pathogens. However, investigations of vector-borne pathogens harbored by kissing bugs are rare.

Methods

In the current study, 22 adult kissing bugs (Triatoma rubrofasciata) were captured in Huizhou City, Guangdong Province, south China. The presence of vector-borne pathogens in the kissing bugs was tested, and the genetic diversity of these potential pathogens was investigated.

Results

All the kissing bugs were negative for Anaplasmataceae bacteria, Rickettsia, and Coxiella. Bartonella DNA was detected in 36.4% (8/22) of the kissing bugs. The sequences of the Bartonella gltA genes divided into two clades in a phylogenetic tree, with close relationships to B. tribocorum and uncultured Bartonella sp. clone MYR-283, respectively. All the groEL sequences were closely related to those of B. kosoyi (identity 98.75%-100%). The ftsZ and rpoB sequences were most closely related to those of B. elizabethae, a recognized human pathogen, with nucleotide similarities of 98.70%-100% and 99.45%-100%, respectively.

Conclusions

We report the detection of Bartonella DNA in Triatoma kissing bugs in southern China. Although the sample size is limited, the high positive rate of detection of Bartonella DNA, the close relationship of the gene sequences to those of zoonotic Bartonella species, and the distribution of the kissing bugs near human residences, hint at a risk to public health.

The diverse genetic genotypes of Bartonella species circulating in rodents from Inner Mongolia, Northern China

Bartonella are generally recognized as zoonotic pathogens of mammals, including many rodent species. However, data on the genetic diversity of Bartonella in some regions are still absent in China. In this study, we collected rodent samples (Meriones unguiculatus, Spermophilus dauricus, Eolagurus luteus, and Cricetulus barabensis) from Inner Mongolia located in Northern China. The Bartonella were detected and identified by sequencing the gltA, ftsZ, ITS, and groEL genes in them. An overall 47.27% (52/110) positive rate was observed. This may be the first report that M. unguiculatus and E. luteus harbor Bartonella. Phylogenetic and genetic analysis on gltA, ftsZ, ITS, and groEL genes indicated that the strains were divided into seven distinct clades, suggesting the diverse genetic genotypes of Bartonella species in this area. Of those, Clade 5 meets the criteria for identification as a novel species based on gene sequence dissimilarity to known Bartonella species and herein we name it "Candidatus Bartonella mongolica".

Infection by a previously uncharacterized Ehrlichia species in rodents from Inner Mongolia, Northern China

Ehrlichia are intracellular bacteria of medical importance to both humans and domestic animals. They are mainly vectored by ticks and harbored by domestic and wild animals such as rodents. In this study, we investigated the prevalence and genetic diversity of Ehrlichia in rodents from Inner Mongolia Autonomous Region, Northern China. In 2021, a total of 359 rodents representing 10 species were captured in two locations of Inner Mongolia: Siziwang Banner and Ar Horqin Banner. Subsequently, an Ehrlichia was detected and characterized in three Spermophilus dauricus and one Meriones unguiculatus. Its rrs, gltA, and groEL sequences have the highest identities of 100%, 87.9%, and 99.7% to known Ehrlichia species, respectively, and they form distinct clades in the phylogenetic trees. Ehrlichia strains mostly related to this species have been detected in ticks from Russia, suggesting that it may be exposed to humans and animals through tick bites. The pathogenicity of this Ehrlichia should be further studied.

Genetic diversity of Bartonella infection in residential and field rodents in Hebei, China

Rodents are the primary natural reservoirs of Bartonella spp., and some of which are zoonotic causative agents. Hence, surveillance of Bartonella sp. infection in rodents is very important for the prevention of human bartonellosis caused by them. In this study, rodents were captured, and their spleen samples were collected for Bartonella sp. DNA detection and identification by amplifying the 16S rRNA, gltA, and ftsz genes using semi-nested polymerase chain reaction (PCR). The results indicated that Bartonella sp. DNA was detected in seven Rattus norvegicus individuals with a detection rate of 6.7% in Chengde City and bacterial DNA in 31 Apodemus agrarius individuals with a detection rate of 28.4% in Handan City. The DNA detection rate across the genders and ages of rodents was not found to be statistically significant. Furthermore, sequence analysis of the above-mentioned three genes demonstrated that at least eight Bartonella species were circulating in Hebei Province, of which three, including Bartonella rattimassiliensis, Bartonella grahamii, and Bartonella tribocorum, are human pathogens, thus suggesting the existence of a major public health risk. Overall, these results revealed the detection rate and genetic diversity of Bartonella species infection in rodents in Hebei Province, which could be potentially helpful for the prevention of bartonellosis caused by rodent-associated Bartonella species. This study highlights the urgent need for the surveillance of Bartonella infections in rodents and ectoparasites that affect both rodents and humans and can cause fever of unknown origin or endocarditis.