Bartonella infection in rodents and their flea ectoparasites: an overview

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.

Comparative study on Bartonella infection in spleen and kidney of small mammals from Mile City and Lianghe County, Yunnan Province

Background

Bartonellosis is a zoonotic infectious disease caused by Bartonella spp. Small mammals are the most important hosts of Bartonella and play an important role in its long-term maintenance and spread. The multi-organ studies help understand the Bartonella prevalence of hosts more systematically and comprehensively. This study aimed to investigate the prevalence of Bartonella in small mammals and explore the genetic diversity of the infected strains and the influencing factors from Mile City and Lianghe County, Yunnan Province.

Methods

Small mammals were captured in Mile City and Lianghe County of Yunnan Province from July to August 2019. Spleen and kidney tissues were collected and the gltA gene was amplified to detect and analyze the prevalence of Bartonella in two regions and two organs.

Results

The prevalence of Bartonella in small mammals was 14.29% (43/301). Lianghe County's risk of infection was 3.79-fold (95%CI: 1.39-13.35) compared to that of Mile City. The risk of infection in Rattus tanezumi was increased by 90% compared to Suncus murinus (95%CI: 0.01-0.63). The small mammals with tail lengths > 132 mm infected by Bartonella were 6.34 folds than that with tail lengths ≤ 132 mm (95%CI: 1.87-23.39). The spleen had a higher infection rate of 12.11% (35/289) than the kidney at 7.33% (22/300) (χ 2 = 4.966, p = 0.026). There were no statistically significant differences in the prevalence of Bartonella among small mammals with different habitats, sex, age, flea infestation status, body weight, body length, hindfoot length, and ear height. Five Bartonella species were isolated in seven species of small mammals. Bartonella tribocorum is the dominant species in both regions, and it has a genetic relationship with the zoonotic pathogen Bartonella elizabethae.

Conclusion

This study showed the prevalence of Bartonella in small mammals from Mile City and Lianghe County of Yunnan Province was high, and there were more types of Bartonella infection species. The spleen was more conducive to the growth and reproduction of Bartonella. The results of the study will help to prevent and control Bartonella infection and transmission to humans from small mammals in the two regions and provide a reference basis for further research on Bartonella infection in Yunnan or other similar regions.

Genetic diversity of Bartonella spp. in rodents and fleas from Poland

Bartonella spp. are parasites of mammalian erythrocytes and endothelial cells, and are transmitted by blood-feeding arthropod ectoparasites, including fleas. This study aimed to: (i) identify the main flea species responsible for Bartonella transmission and the specific Bartonella species they carry, (ii) evaluate how host-related factors influence the prevalence of Bartonella, (iii) examine the genetic diversity of Bartonella from different flea species and mammalian hosts, including rodents and European moles, and (iv) determine the haplotypes of Bartonella derived from rodents. Blood samples were collected from seven rodent species and two European moles in Poland (n = 994), and fleas were collected from rodents (n = 833). Bartonella spp. were identified and genotyped through rpoB and gltA genes. Phylogenetic analysis revealed two dominant Bartonella spp. in rodents and fleas: B. grahamii and B. taylorii. Moreover, 17 haplotypes of B. taylorii and 9 of B. grahamii were identified. The sequences of Bartonella sp. from T. europaea clustered in a unique separate group, possibly indicating a novel species. The study confirmed fleas as vectors of Bartonella transmission in rodents and highlighted the significant genetic diversity of Bartonella spp. in both fleas and rodents.

Bartonella tracing in wild rodents in northwestern Mexico

Bartonella is a widely distributed Gram-negative bacterium that includes species that are capable of causing illness in humans. Rodents represent one of the main reservoirs of zoonotic pathogens, and monitoring their populations can provide valuable insights into human health. We conducted a surveillance study of rodents from two north-western states of Mexico (Baja California and Chihuahua) to investigate the prevalence and genetic diversity of Bartonella by polymerase chain reaction (PCR) amplification and sequencing of the citrate synthase (gltA) gene. A total of 586 rodents belonging to 28 species were captured, and 408 were tested for Bartonella spp. The overall Bartonella spp. prevalence was 39.71%. The prevalence found in Chihuahua was higher (42.80%) than in Baja California (32.52%), and rodents such as Neotoma albigula, Neotoma mexicana, Peromyscus boylii, and Chaetodipus baileyi had the highest prevalence. The gltA sequences revealed seven genetic variants, some of which were obtained from Peromyscus and Dipodomys rodents and were associated with Bartonella species of human health concern, such as B. grahamii and B. vinsonii subsp. arupensis. In addition, a sequence obtained from a Peromyscus maniculatus was clustered with Candidatus Bartonella rudakovii, a previously unreported association. This study provides valuable data and new insight into the Bartonella-hosts interactions in rodent species in north-western Mexico.

Epidemiological characteristics and genetic diversity of Bartonella species from rodents in Guangxi Zhuang autonomous region, Southwestern China

Bartonella spp. are gram-negative bacteria recognized as zoonotic pathogens of wide spectrum mammals. Rodents are recognized as a natural reservoir of pathogens, and many Bartonella species transmitted by various blood-sucking arthropods have been detected in various rodents populations. In Guangxi Zhuang Autonomous Region, humans have a habit of preying on rodents, however, data on the genetic diversity of Bartonella are still absent. Investigating the epidemiological characteristics of Bartonella infection in rodents is of great significance for the prevention and control of human Bartonellosis. In this study, rodents were captured to monitor the prevalence of Bartonella in four cities in Guangxi Zhuang Autonomous Region, Southwestern China. Six species of Bartonella, including three confirmed zoonotic species, were detected based on the rrs gene with an overall prevalence of 11.5 % (32/278) in rodents. Bartonella tribocorum (21/32, 65.6 %) was the predominant species among the three zoonotic Bartonella species. In addition, phylogenetic and genetic analyses of the rrs, gltA, and rpoB genes indicated that the strains were divided into distinct clade within the same rodent, suggesting the co-circulating of diverse genetic genotypes of Bartonella species. These results provide insights into the prevalence and genetic diversity of Bartonella species circulating in rodents in Guangxi Zhuang Autonomous Region, and also urged the surveillance of rodent-associated Bartonella species in these areas.

Small mammals as hosts of vector-borne pathogens in the High Tatra Mountains region in Slovakia, Central Europe

Rodents and insectivores are significant reservoirs of many zoonotic pathogens, contributing to the transmission of diseases affecting human and animal health. This study investigated the prevalence and diversity of vector-borne pathogens in small mammals within the High Tatras region of Slovakia, an area with substantial recreational activity and protected zones. A total of 156 small mammals, comprising ten species, were screened for pathogens such as Bartonella spp., Borrelia spp., Anaplasma phagocytophilum, and Babesia spp. The prevalence of vector-borne pathogens in the studied animals reached 74.35%, with Bartonella spp. being the most common, identified in 57.7% of the animals, particularly in Apodemus flavicollis and Clethrionomys glareolus. Borrelia burgdorferi (sensu lato) was detected in 11.5% of the rodents, with Borrelia afzelii identified as the predominant species. Babesia microti was found in A. flavicollis and Mus musculus, with a total prevalence of 3.2%. The lowest was the prevalence of A. phagocytophilum reaching 1.9%. This study provides evidence of the significant role of rodents as reservoirs of vector-borne pathogens in protected areas of the High Tatras region and Tatra National Park.

Genetic diversity of Bartonella spp. among cave-dwelling bats from Colombia

Bartonella is a bacterial genus that comprises arthropod-borne microorganisms. Several Bartonella isolates have been detected from bats worldwide, which are thought to be undescribed species. We aimed to test the presence of Bartonella spp. among bats from Colombia, and evaluate the genetic diversity of bat-associated Bartonella spp. through phylogenetic analyses. A total of 108 bat blood samples were collected from three bat species (Carollia perspicillata, Mormoops megalophylla, and Natalus tumidirostris) that inhabit the Macaregua cave. The Bartonella ssrA gene was targeted through real-time and end-point PCR; additionally, the gltA and rpoB genes were detected by end-point PCR. All obtained amplicons were purified and bidirectionally sequenced for phylogenetic analysis using a concatenated supermatrix and a supertree approaches. A detection frequency of 49.1 % (53/108) for Bartonella spp. was evidenced among bat blood samples, of which 59.1 % (26/44), 54.3 % (19/35) and 27.6 % (8/29) were identified in Carollia perspicillata, Natalus tumidirostris and Mormoops megalophylla respectively. A total of 35 ssrA, 5 gltA and 4 rpoB good-quality sequences were obtained which were used for phylogenetic analysis. All obtained bat sequences clustered together with sequences obtained from Neotropical bat species into two bat-restricted clades namely clade A and clade N. We detected the presence of Bartonella spp. that clustered within two different bat-associated Bartonella clades, giving the first data of the genetic diversity of these bacteria among bats from Colombia.

From host individual traits to community structure and composition: Bartonella infection insights

BACKGROUND

Phylogeny, combined with trait-based measures, offers insights into parasite sharing among hosts. However, the specific traits that mediate transmission and the aspects of host community diversity that most effectively explain parasite infection rates remain unclear, even for the Bartonella genus, a vector-borne bacteria that causes persistent blood infections in vertebrates.

METHODS

This study investigated the association between rodent host traits and Bartonella infection, as well as how rodent community diversity affects the odds of infection in the Atlantic Forest, using generalized linear models. Additionally, we assessed how host traits and phylogenetic similarities influence Bartonella infection among mammal species in Brazil. To this end, rodents were sampled from ten municipalities in Rio de Janeiro, southeastern Brazil. Then, we calculated several diversity indices for each community, including Rényi's diversity profiles, Fisher's alpha, Rao's quadratic entropy (RaoQ), Functional Diversity (FDis), Functional Richness (FRic), and Functional Evenness (FEve). Finally, we compiled a network encompassing all known interactions between mammal species and Bartonella lineages recorded in Brazil.

RESULTS

We found no significant relationship between diversity indices and the odds of Bartonella infection in rodent communities. Furthermore, there was no statistical support for the influence of individual-level traits (e.g., body length, sex, and age) or species-level ecological traits (e.g., locomotor habitat, dietary guild, and activity period) on Bartonella infection in rodents. A country-scale analysis, considering all mammal species, revealed no effect of host traits or phylogeny on Bartonella infection.

CONCLUSIONS

This study highlighted wild mammals that share Bartonella lineages with livestock, synanthropic, and domestic animals, underscoring the complexity of their maintenance cycle within the One Health framework. A key question arising from our findings is whether molecular host-cell interactions outweigh host body mass and ecological traits in influencing Bartonella infection, potentially opening new avenues for understanding host-parasite relationships and infection ecology.

Genetic diversity of Bartonella species in small mammals in the Qinghai Menyuan section of Qilian Mountain National Park, China

Bartonella are vector-borne gram-negative facultative intracellular bacteria that can infect a wide spectrum of mammals, and are recognized as emerging human pathogens. This study aimed to investigate the prevalence and molecular characteristics of Bartonella infections in small mammals within the Qinghai Menyuan section of Qilian Mountain National Park, China. Small mammals were captured, and the liver, spleen and kidney were collected for Bartonella detection and identification using a combination of real-time PCR targeting the transfer-mRNA (ssrA) gene and followed by sequencing of the citrate synthase (gltA) gene. A total of 52 rodents were captured, and 36 rodents were positive for Bartonella, with a positivity rate of 69.23% (36/52). Bartonella was detected in Cricetulus longicaudatus, Microtus oeconomus, Mus musculus, and Ochotona cansus. The positivity rate was significantly different in the different habitats. Two Bartonella species were observed, including Bartonella grahamii and Bartonella heixiaziensis, and B. grahamii was the dominant epidemic strain in this area. Phylogenetic analysis showed that B. grahamii mainly clustered into two clusters, which were closely related to the Apodemus isolates from China and Japan and the local plateau pika isolates, respectively. In addition, genetic polymorphism analysis showed that B. grahamii had high genetic diversity, and its haplotype had certain regional differences and host specificity. Overall, high prevalence of Bartonella in small mammals in the Qinghai Menyuan section of Qilian Mountain National Park. B. grahamii is the dominant strain with high genetic diversity and potential pathogenicity to humans, and corresponding control measures should be considered.

Aetiologies of bacterial tick-borne febrile illnesses in humans in Africa: diagnostic limitations and the need for improvement

Tick-borne febrile illnesses caused by pathogens like Anaplasma spp., Bartonella spp., Borrelia spp., Ehrlichia spp., Coxiella burnetii, Francisella tularensis, and Rickettsia spp., are significant health concerns in Africa. The epidemiological occurrence of these pathogens is closely linked to the habitats of their vectors, prevalent in rural and semi-urban areas where humans and livestock coexist. The overlapping clinical presentations, non-specific symptoms, and limited access to commercially available in vitro diagnostics in resource-limited settings exacerbate the complexity of accurate diagnoses. This review aimed to systematically extract and analyze existing literature on tick-borne febrile illnesses in Africa, highlighting the diagnostic challenges and presenting an up-to-date overview of the most relevant pathogens affecting human populations. A comprehensive literature search from January 1990 to June 2024 using databases like PubMed, Cochrane Library, Science Direct, EMBASE, and Google Scholar yielded 13,420 articles, of which 70 met the inclusion criteria. Anaplasma spp. were reported in Morocco, Egypt, and South Africa; Francisella spp. in Kenya and Ethiopia; Ehrlichia spp. in Cameroon; Bartonella spp. in Senegal, Namibia, South Africa, and Ethiopia; Borrelia spp. in Senegal, Gabon, Tanzania, and Ethiopia; Coxiella burnetii in 10 countries including Senegal, Mali, and South Africa; and Rickettsia spp. in 14 countries including Senegal, Algeria, and Uganda. Data were analyzed using a fixed-effect model in R version 4.0.1 and visualized on an African map using Tableau version 2022.2. This review highlights the urgent need for improved diagnostics to better manage and control tick-borne febrile illnesses in Africa.

Bartonella, Blechomonas and Trypanosoma in fleas from the long-tailed ground squirrel (Spermophilus undulatus) in northwestern China

Fleas are known to be vectors for a variety of pathogens in veterinary medicine. However, no information is available on the presence of Bartonella and Trypanosomatidae in fleas of the long-tailed ground squirrel (LTGR, Spermophilus undulatus). The present study shows detection of these pathogens in LTGR fleas. During 2022-2023, a total of 396 fleas were collected from 91 LTGRs in 4 alpine regions of Xinjiang Uygur Autonomous Region (northwestern China) and grouped into 54 flea pools. Flea species were identified according to morphological characteristics and molecular data. In addition, all flea samples were analyzed for Bartonella with amplification and sequencing of a 380-bp part of the gltA gene and Trypanosomatidae with targeting the 18S rRNA (850-bp) and gGAPDH (820-bp) genes. The flea species included Frontopsylla elatoides elatoides (203), Neopsylla mana (49), and Citellophilus tesquorum dzetysuensis (144). Of 54 flea pools, seven (12.96%) tested positive for Bartonella, and three (5.56%) were positive for Trypanosomatidae. Based on BLASTn and phylogenetic analyses, i) Bartonella washoensis in F. elatoides elatoides and C. tesquorum dzetysuensis, and Bartonella rochalimae in F. elatoides elatoides were identified. Interestingly, a new haplotype within the species Ba. washoensis was discovered in C. tesquorum dzetysuensis; and ii) Blechomonas luni was confirmed in C. tesquorum dzetysuensis and Trypanosoma otospermophili in F. elatoides elatoides. Two Bartonella species and two Trypanosomatidae members were discovered for the first time in fleas from LTGRs. This study broadens our understanding of the geographic distribution and potential vectors for Bartonella and Trypanosomatidae.

Bartonella species in dromedaries and ruminants from Lower Shabelle and Benadir regions, Somalia

BACKGROUND

Bartonellosis, caused by bacteria of the genus Bartonella, is a zoonotic disease with several mammalian reservoir hosts. In Somalia, a country heavily reliant on livestock, zoonotic diseases pose significant public health and economic challenges. To the best of our knowledge, no study has been performed aiming to verify the occurrence of Bartonella spp. in Somalia. This study investigated the occurrence and molecular characterization of Bartonella in dromedary (Camelus dromedarius, Linnaeus, 1758), cattle, sheep, and goats from Somalia.

MATERIALS AND METHODS

530 blood samples were collected from various animals (155 dromedary, 199 goat, 131 cattle, and 45 sheep) in Benadir and Lower Shabelle regions. DNA was extracted for molecular analysis, and a qPCR assay targeting the NADH dehydrogenase gamma subunit (nuoG) gene was used for Bartonella screening. Positive samples were also subjected to PCR assays targeting seven molecular markers including: nuoG, citrate synthase gene (gltA), RNA polymerase beta-subunit gene (rpoB), riboflavin synthase gene (ribC), 60 kDa heat-shock protein gene (groEL), cell division protein gene (ftsZ), and pap31 and qPCR targeting the 16-23S rRNA internal transcribed spacer (ITS) followed by Sanger sequencing, BLASTn and phylogenetic analysis.

RESULTS

Out of 530 tested animals, 5.1% were positive for Bartonella spp. by the nuoG qPCR assay. Goats showed the highest Bartonella occurrence (17/199, 8.5%), followed by sheep (6/44, 6.8%), cattle (4/131, 3.1%), and dromedary (1/155, 1.9%). Goats, sheep, and cattle had higher odds of infection compared to dromedary. Among nuoG qPCR-positive samples, 11.1%, 14.8%, 11.1%, and 25.9% were positive in PCR assays based on nuoG, gltA, and pap31 genes, and in the qPCR based on the ITS region, respectively. On the other hand, nuoG qPCR-positive samples were negative in the PCR assays targeting the ribC, rpoB, ftsZ, and groEL genes. While Bartonella bovis sequences were detected in cattle (nuoG and ITS) and goats (gltA), Bartonella henselae ITS sequences were detected in dromedary, goat, and sheep. Phylogenetic analysis placed gltA Bartonella sequence from a goat in the same clade of B. bovis.

CONCLUSION

The present study showed, for the first time, molecular evidence of Bartonella spp. in dromedary and ruminants from Somalia and B. henselae in sheep and goats globally. These findings contribute valuable insights into Bartonella spp. occurrence in Somali livestock, highlighting the need for comprehensive surveillance and control measures under the One Health approach.

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.

Epidemiological survey and genetic diversity of Bartonella in fleas collected from rodents in Fujian Province, Southeast China

BACKGROUND

Fleas, considered to be the main transmission vectors of Bartonella, are highly prevalent and show great diversity. To date, no investigations have focused on Bartonella vectors in Southeast China. The aim of this study was to investigate the epidemiological and molecular characteristics of Bartonella in fleas in Southeast China.

METHODS

From 2016 to 2022, flea samples (n = 1119) were collected from 863 rodent individuals in seven inland and coastal cities in Southeast China. Flea species, region, gender, host species and habitat were recorded. The DNA samples from each individual flea were screened by real-time PCR for the Bartonella ssrA gene. All positive samples were confirmed by PCR based on the presence of the gltA gene and sequenced. The factors associated with Bartonella infection were analyzed by the Chi-square test and Fisher's exact test. ANOVA and the t-test were used to compare Bartonella DNA load.

RESULTS

Bartonella DNA was detected in 26.2% (293/1119) of the flea samples, including in 27.1% (284/1047) of Xenopsylla cheopis samples, 13.2% (5/38) of Monopsyllus anisus samples, 8.3% (2/24) of Leptopsylla segnis samples and 20.0% (2/10) of other fleas (Nosopsyllus nicanus, Ctenocephalides felis, Stivalius klossi bispiniformis and Neopsylla dispar fukienensis). There was a significant difference in the prevalence of Bartonella among flea species, sex, hosts, regions and habitats. Five species of Bartonella fleas were identified based on sequencing and phylogenetic analyses targeting the gltA gene: B. tribocorum, B. queenslandensis, B. elizabethae, B. rochalimae and B. coopersplainsensis.

CONCLUSIONS

There is a high prevalence and diversity of Bartonella infection in the seven species of fleas collected in Southeast China. The detection of zoonotic Bartonella species in this study, including B. tribocorum, B. elizabethae and B. rochalimae, raises public health concerns.

Evaluation of the available animal models for Bartonella infections

The diseases caused by the Bartonella genus of bacteria are clinically diverse, and can be challenging to cure. The study of bartonellosis has been hampered by the lack of a suitable animal model. Preclinical studies for novel therapeutics and a competent host for vector transmission studies are needed to fill critical knowledge gaps. The studies included here are a representation of in vivo Bartonella research and the corresponding challenges. This review examines the current state of available animal models by assessing the success of various model species and strains in Bartonella infection. With a focus on the strengths and weaknesses of current animal models, the importance of these models for improvement of human health and veterinary care is emphasized.

Unique microbial communities of parasitic fleas on wild animals from the Qinghai-Tibet Plateau

Fleas, one of the most significant ectoparasites, play a crucial role as vectors in spreading zoonotic diseases globally. The Qinghai Province, as part of the Qinghai-Tibet Plateau, is one of the provinces in China with the largest number of flea species. In this study, we characterized the microbial communities of eighty-five adult fleas, belonging to nineteen species within four families (Ceratophyllidae, Ctenophthalmidae, Leptopsyllidae, and Pulicidae). We identified a total of 1162 unique operational taxonomic units at the genus level, with flea-borne pathogens such as Wolbachia, Bartonella, Rickettsia being the members of top abundant taxa. Except for comparison between Ctenophthalmidae and Leptopsyllidae families, the analyses of both alpha- and beta- diversity indicators suggested that bacterial diversity varied among flea families. This could be attributed to flea phylogeny, which also influenced by their geographical sites and animal hosts. Results of Linear discriminant analysis effect size (LEfSe) indicated that 29 genera in Ceratophylloidea, 11 genera in Ctenophthalmidae, 15 genera in Leptopsyllidae, and 22 genera in Pulicidae were significantly responsible for explaining the differences among the four flea families (linear discriminant analysis score > 2, P < 0.05). Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) analyses showed that the functional pathways varied significantly across flea families, which was supported by the significant correlation between the functional pathways and the microbial communities.

Molecular detection and characterization of Bartonella spp. in small mammals in the Amazonia and Cerrado biomes, midwestern Brazil

Although Bartonella spp. have been worldwide described in rodents and bats, few studies have reported these agents in marsupials. The present work aimed to investigate the occurrence and genetic diversity of Bartonella in small mammals (rodents, marsupials, and bats) and associated ectoparasites in two ecoregions (Amazonia and Cerrado biomes) in midwestern Brazil. For this purpose, DNA samples from 378 specimens of small mammals (128 rodents, 111 marsupials, and 139 bats) and 41 fleas (Siphonaptera) were screened for the Bartonella genus employing a quantitative real-time PCR assay (qPCR) based on the nuoG (nicotinamide adenine dinucleotide dehydrogenase gamma subunit) gene. Then, positive samples in qPCR were submitted to conventional PCR (cPCR) assays targeting the gltA, ftsZ, and rpoB genes. One (0.78 %) rodent, 23 (16.54 %) bats, and 3 (7.31 %) fleas showed positive results in the qPCR for Bartonella sp. After cPCR amplification and sequencing, 13 partial Bartonella DNA sequences of the following genes were obtained only from bats´ blood samples: 9 gltA (citrate synthase), 3 ftsZ (cell division protein), and 1 rpoB (RNA polymerase beta subunit). The maximum likelihood inference based on the gltA gene positioned the obtained sequences in three different clades, closely related to Bartonella genotypes previously detected in other bat species and bat flies sampled in Brazil and other countries from Latin America. Similarly, the ftsZ sequences clustered in two different clades with sequences described in bats from Brazil, other countries from Latin America, and Georgia (eastern Europe). Finally, the Bartonella rpoB from a specimen of Lophostoma silvicolum clustered with a Bartonella sp. sequence obtained from a Noctilio albiventris (KP715475) from French Guiana. The present study provided valuable insights into the diversity of Bartonella genotypes infecting bats from two ecoregions (Amazonia and Cerrado) in midwestern Brazil and emphasized that further studies should be conducted regarding the description and evaluation of different lineages of Bartonella in wild small mammals and their ectoparasites in different Brazilian biomes.

Molecular prevalence of vector borne bacterial pathogens in the blood samples of wild rodent species trapped from Saudi Arabia

Order Rodentia is the most speciose among mammals and the members of this order are known to host more than 60 zoonotic diseases and rodents are a potential health threat to humans. This study was designed to report the molecular prevalence and phylogenetic evaluation of various blood borne bacterial pathogens (Anaplasma ovis, Anaplasma phagocytophilum, Anaplasma marginale and Bartonella spp.) in the blood samples of four wild rodent species [Meriones rex (N = 27), Acomys dimidiatus (N = 18), Myomys yemeni (N = 6) and Rattus rattus (N = 3)] that were trapped during August till October 2020 from Al Makhwah governorate in Saudi Arabia. Results revealed by 9/54 (16.6%) rodents amplified Msp4 gene and 2/54 (3.7%) rodents amplified rpoB gene of Anaplasma ovis and Bartonella spp. respectively. Anaplasma phagocytophilum and Anaplasma marginale were not detected among enrolled rodent species. Meriones rex was the most highly infected rodent species. DNA sequencing and BLAST analysis confirmed the presence of Anaplasma ovis and the Bartonella koehlerae in rodent blood samples. Phylogenetic analysis of both pathogens showed that Saudi isolates were clustered together and were closely related to isolates that were reported from worldwide countries. Risk factor analysis revealed that prevalence of both bacterial pathogens was not restricted to a particular rodent species or a rodent sex (P > 0.05). In conclusion, we are reporting for the very first time that Saudi rodents are infected with Anaplasma ovis and rodents can be infected with Bartonella koehlerae. Similar studies at large scale are recommended in all those areas of Saudi Arabia that are unexplored for the incidence and prevalence of bacterial pathogens among the rodents that are living near human dwellings in order to prevent bacterial infections in local people as well as in livestock.

Epidemiology of feline bartonellosis and molecular characteristics of Bartonella henselae in Bangladesh

Bartonellosis, a neglected vector-borne zoonotic disease transmitted from animals to humans, continues to threaten human and animal health significantly. This study aims to determine the epidemiology of feline bartonellosis and the molecular characteristics of Bartonella spp. in cats. From June 2018 to June 2020, 304 oral swabs were randomly collected from Bangladesh's Dhaka, Mymensingh, and Rajshahi districts. A pre-tested questionnaire was administered to collect data. Oral swabs were subjected to PCR targeting htrA gene to confirm Bartonella spp., which was subsequently validated through sequencing. Risk factors were identified using multivariable logistic regression analysis. The overall prevalence of feline bartonellosis was found to be 15.1 %. The following factors were significantly (p < 0.05) associated with Bartonella infection in risk factor analysis: cats aged ≥ 1 year (OR: 3.23, 95 % CI: 1.38-24.40), local breed cats (OR: 3.37, 95 % CI: 1.05-10.81), cats carrying fleas (OR: 2.33, 95 % CI: 1.93-13.45), antifleacidal drugs inconsistently administered cats (OR: 6.74, 95 % CI: 3.17-14.31), outdoor access cats (OR: 2.54, 95 % CI: 1.16-5.57). Notably, zoonotic B. henselae was confirmed through sequencing, establishing it as the causal agent of cat scratch disease. Phylogenetic analysis showed homology with B. henselae sequences from Brazil, Saint Kitts, and Nevis. We recommend consistent and appropriate flea control measures to curb its spread among Bangladeshi cats. Moreover, limiting outdoor exposure or implementing preventive measures for outdoor cats could reduce the disease burden. The associated human health risk can be decreased by effectively controlling this disease within the cat population.

Cattle Farming and Plantation Forest are Associated with Bartonella Occurrence in Wild Rodents

Bartonella spp. are intracellular hemotropic bacteria primarily transmitted by arthropod vectors to various mammalian hosts, including humans. In this study, we conducted a survey on wild populations of sigmodontine rodents, Akodon azarae and Oxymycterus rufus, inhabiting the Paraná River delta region. The study involved eight grids organized in a crossed 2 × 2 design, where four of the grids were exposed to cattle while the other four were not, and four grids were located in implanted forest while the remaining four were in natural grasslands. Our objective was to examine whether the occurrence of Bartonella spp. in rodents was associated with silvopastoral activities (cattle raising associated with timber production) conducted in the region. Additionally, we evaluated the associations between Bartonella infection and other environmental and host factors. We present compelling evidence of a significant positive association between Bartonella prevalence and the presence of implanted forests and cattle. Furthermore, we identified the presence of a Bartonella genotype related to the pathogen Bartonella rochalimaea, infecting both A. azarae and Ox. rufus. These findings suggest that anthropogenic land-use changes, particularly the development of silvopastoral practices in the region, may disrupt the dynamics of Bartonella.

Two novel Bartonella (sub)species isolated from edible dormice (Glis glis): hints of cultivation stress-induced genomic changes

Bartonelloses are neglected emerging infectious diseases caused by facultatively intracellular bacteria transmitted between vertebrate hosts by various arthropod vectors. The highest diversity of Bartonella species has been identified in rodents. Within this study we focused on the edible dormouse (Glis glis), a rodent with unique life-history traits that often enters households and whose possible role in the epidemiology of Bartonella infections had been previously unknown. We identified and cultivated two distinct Bartonella sub(species) significantly diverging from previously described species, which were characterized using growth characteristics, biochemical tests, and various molecular techniques including also proteomics. Two novel (sub)species were described: Bartonella grahamii subsp. shimonis subsp. nov. and Bartonella gliris sp. nov. We sequenced two individual strains per each described (sub)species. During exploratory genomic analyses comparing two genotypes ultimately belonging to the same species, both factually and most importantly even spatiotemporally, we noticed unexpectedly significant structural variation between them. We found that most of the detected structural variants could be explained either by prophage excision or integration. Based on a detailed study of one such event, we argue that prophage deletion represents the most probable explanation of the observed phenomena. Moreover, in one strain of Bartonella grahamii subsp. shimonis subsp. nov. we identified a deletion related to Bartonella Adhesin A, a major pathogenicity factor that modulates bacteria-host interactions. Altogether, our results suggest that even a limited number of passages induced sufficient selective pressure to promote significant changes at the level of the genome.

Bartonella Infection in Fruit Bats and Bat Flies, Bangladesh

Bats harbor diverse intracellular Bartonella bacteria, but there is limited understanding of the factors that influence transmission over time. Investigation of Bartonella dynamics in bats could reveal general factors that control transmission of multiple bat-borne pathogens, including viruses. We used molecular methods to detect Bartonella DNA in paired bat (Pteropus medius) blood and bat flies in the family Nycteribiidae collected from a roost in Faridpur, Bangladesh between September 2020 and January 2021. We detected high prevalence of Bartonella DNA in bat blood (35/55, 64%) and bat flies (59/60, 98%), with sequences grouping into three phylogenetic clades. Prevalence in bat blood increased over the study period (33% to 90%), reflecting an influx of juvenile bats in the population and an increase in the prevalence of bat flies. Discordance between infection status and the clade/genotype of detected Bartonella was also observed in pairs of bats and their flies, providing evidence that bat flies take blood meals from multiple bat hosts. This evidence of bat fly transfer between hosts and the changes in Bartonella prevalence during a period of increasing nycteribiid density support the role of bat flies as vectors of bartonellae. The study provides novel information on comparative prevalence and genetic diversity of Bartonella in pteropodid bats and their ectoparasites, as well as demographic factors that affect Bartonella transmission and potentially other bat-borne pathogens.

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.

Bartonella infections are prevalent in rodents despite efficient immune responses

BACKGROUND

Pathogens face strong selection from host immune responses, yet many host populations support pervasive pathogen populations. We investigated this puzzle in a model system of Bartonella and rodents from Israel's northwestern Negev Desert. We chose to study this system because, in this region, 75-100% of rodents are infected with Bartonella at any given time, despite an efficient immunological response. In this region, Bartonella species circulate in three rodent species, and we tested the hypothesis that at least one of these hosts exhibits a waning immune response to Bartonella, which allows reinfections.

METHODS

We inoculated captive animals of all three rodent species with the same Bartonella strain, and we quantified the bacterial dynamics and Bartonella-specific immunoglobulin G antibody kinetics over a period of 139 days after the primary inoculation, and then for 60 days following reinoculation with the same strain.

RESULTS

Contrary to our hypothesis, we found a strong, long-lasting immunoglobulin G antibody response, with protective immunological memory in all three rodent species. That response prevented reinfection upon exposure of the rodents to the same Bartonella strain.

CONCLUSIONS

This study constitutes an initial step toward understanding how the interplay between traits of Bartonella and their hosts influences the epidemiological dynamics of these pathogens in nature.

Molecular detection and characterization of Bartonella spp. in rodents from central and southern Chile, with emphasis on introduced rats (Rattus spp.)

Bartonella spp. was screened in 155 rodents from Chile, mainly the invasive rats Rattus norvegicus and Rattus rattus. A total of 155 spleen and 50 blood samples were analyzed through real-time PCR for Bartonella spp. (nuoG gene). Positive samples were subjected to amplification of fragment of loci gltA, rpoB and ITS by conventional PCR (cPCR). Overall, 43 spleen samples (27.7%) and 6 rodent blood samples (12%) were positive for nuoG-Bartonella spp. Positive samples were found in R. norvegicus, R. rattus, Abrothrix olivacea and Oligoryzomys longicaudatus. Bartonella spp. DNA was amplified by cPCR in 16 samples, resulting in 21 sequences (6 gltA, 5 ITS and 10 rpoB). Sequencing and phylogenic analyses identified genotypes from Rattus spp., potentially belonging to Bartonella coopersplainsensis, Bartonella henselae, Bartonella tribocorum, and an undescribed Bartonella sp. From native rodents, one sequence was identified, being related B. machadoae. In conclusion, this work describes diverse and potentially zoonotic Bartonella spp. genotypes in Rattus spp. Additionally, this is the first report of Bartonella in O. longicaudatus, including a potentially novel Bartonella genotype or species.

Patterns and drivers of vector-borne microparasites in a classic metapopulation

Many organisms live in fragmented populations, which has profound consequences on the dynamics of associated parasites. Metapopulation theory offers a canonical framework for predicting the effects of fragmentation on spatiotemporal host–parasite dynamics. However, empirical studies of parasites in classical metapopulations remain rare, particularly for vector-borne parasites. Here, we quantify spatiotemporal patterns and possible drivers of infection probability for several ectoparasites (fleas, Ixodes trianguliceps and Ixodes ricinus) and vector-borne microparasites (Babesia microti, Bartonella spp., Hepatozoon spp.) in a classically functioning metapopulation of water vole hosts. Results suggest that the relative importance of vector or host dynamics on microparasite infection probabilities is related to parasite life-histories. Bartonella, a microparasite with a fast life-history, was positively associated with both host and vector abundances at several spatial and temporal scales. In contrast, B. microti, a tick-borne parasite with a slow life-history, was only associated with vector dynamics. Further, we provide evidence that life-history shaped parasite dynamics, including occupancy and colonization rates, in the metapopulation. Lastly, our findings were consistent with the hypothesis that landscape connectivity was determined by distance-based dispersal of the focal hosts. We provide essential empirical evidence that contributes to the development of a comprehensive theory of metapopulation processes of vector-borne parasites.

Bartonella raoultii sp. nov., isolated from infected rodents (Mastomys erythroleucus) in Senegal

Bartonella species are involved in various human diseases, causing a range of clinical manifestations; animals are considered as the main reservoirs, transmitting diverse species of Bartonella through direct contact and haematophagous insects. Here, we characterize a new species, Bartonella raoultii sp. nov., within the genus Bartonella, using a taxonogenomic polyphasic approach. Strain 094T (= CSUR B1097T=DSM 28004T), isolated from the blood of an infected rodent (Mastomys erythroleucus) in Senegal, is an aerobic and rod-shaped bacterium. The annotated non-contiguous genome sequence is 1 952322 bp long and contains 37.2 mol% G+C content, 1686 protein-coding genes and 50 RNA genes, including seven rRNA genes.

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".

Species-level microbiota of ticks and fleas from Marmota himalayana in the Qinghai-Tibet Plateau

Introduction

Ticks and fleas, as blood-sucking arthropods, carry and transmit various zoonotic diseases. In the natural plague foci of China, monitoring of Yersinia pestis has been continuously conducted in Marmota himalayana and other host animals, whereas other pathogens carried by vectors are rarely concerned in the Qinghai-Tibet Plateau.

Methods

In this study, we investigated the microbiota of ticks and fleas sampling from M. himalayana in the Qinghai-Tibet Plateau, China by metataxonomics combined with metagenomic methods.

Results

By metataxonomic approach based on full-length 16S rDNA amplicon sequencing and operational phylogenetic unit (OPU) analyses, we described the microbiota community of ticks and fleas at the species level, annotated 1,250 OPUs in ticks, including 556 known species and 492 potentially new species, accounting for 48.50% and 41.71% of the total reads in ticks, respectively. A total of 689 OPUs were detected in fleas, consisting of 277 known species (40.62% of the total reads in fleas) and 294 potentially new species (56.88%). At the dominant species categories, we detected the Anaplasma phagocytophilum (OPU 421) and potentially pathogenic new species of Wolbachia, Ehrlichia, Rickettsia, and Bartonella. Using shotgun sequencing, we obtained 10 metagenomic assembled genomes (MAGs) from vector samples, including a known species (Providencia heimbachae DFT2), and six new species affliated to four known genera, i.e., Wolbachia, Mumia, Bartonella, and Anaplasma. By the phylogenetic analyses based on full-length 16S rRNA genes and core genes, we identified that ticks harbored pathogenic A. phagocytophilum. Moreover, these potentially pathogenic novel species were more closely related to Ehrlichia muris, Ehrlichia muris subsp. eauclairensis, Bartonella rochalimae, and Rickettsia limoniae, respectively. The OPU 422 Ehrlichia sp1 was most related to Ehrlichia muris and Ehrlichia muris subsp. eauclairensis. The OPU 230 Bartonella sp1 and Bartonella spp. (DTF8 and DTF9) was clustered with Bartonella rochalimae. The OPU 427 Rickettsia sp1 was clustered with Rickettsia limoniae.

Discussion

The findings of the study have advanced our understanding of the potential pathogen groups of vectors in marmot (Marmota himalayana) in the Qinghai-Tibet Plateau.

Drivers behind co-occurrence patterns between pathogenic bacteria, protozoa, and helminths in populations of the multimammate mouse, Mastomys natalensis

Advances in experimental and theoretical work increasingly suggest that parasite interactions within a single host can affect the spread and severity of wildlife diseases. Yet empirical data to support predicted co-infection patterns are limited due to the practical challenges of gathering convincing data from animal populations and the stochastic nature of parasite transmission. Here, we investigated co-infection patterns between micro- (bacteria and protozoa) and macroparasites (gastro-intestinal helminths) in natural populations of the multimammate mouse (Mastomys natalensis). Fieldwork was performed in Morogoro (Tanzania), where we trapped 211 M. natalensis and tested their behaviour using a modified open-field arena. All animals were checked for the presence of helminths in their gastro-intestinal tract, three bacteria (Anaplasma, Bartonella, and Borrelia) and two protozoan genera (Babesia and Hepatozoon). Besides the presence of eight different helminth genera (reported earlier), we found that 21% of M. natalensis were positive for Anaplasma, 13% for Bartonella, and 2% for Hepatozoon species. Hierarchical modelling of species communities was used to investigate the effect of the different host-related factors on these parasites' infection probability and community structure. Our results show that the infection probability of Bartonella increased with the host's age, while the infection probability of Anaplasma peaked when individuals reached adulthood. We also observed that less explorative and stress-sensitive individuals had a higher infection probability with Bartonella. Finally, we found limited support for within-host interactions between micro-and macroparasites, as most co-infection patterns could be attributed to host exposure time.

Genomic Characterization of Three Novel Bartonella Strains in a Rodent and Two Bat Species from Mexico

Rodents and bats are the most diverse mammal group that host Bartonella species. In the Americas, they were described as harboring Bartonella species; however, they were mostly characterized to the genotypic level. We describe here Bartonella isolates obtained from blood samples of one rodent (Peromyscus yucatanicus from San José Pibtuch, Yucatan) and two bat species (Desmodus rotundus from Progreso, and Pteronotus parnellii from Chamela-Cuitzmala) from Mexico. We sequenced and described the genomic features of three Bartonella strains and performed phylogenomic and pangenome analyses to decipher their phylogenetic relationships. The mouse-associated genome was closely related to Bartonella vinsonii. The two bat-associated genomes clustered into a single distinct clade in between lineages 3 and 4, suggesting to be an ancestor of the rodent-associated Bartonella clade (lineage 4). These three genomes showed <95% OrthoANI values compared to any other Bartonella genome, and therefore should be considered as novel species. In addition, our analyses suggest that the B. vinsonii complex should be revised, and all B. vinsonii subspecies need to be renamed and considered as full species. The phylogenomic clustering of the bat-associated Bartonella strains and their virulence factor profile (lack of the Vbh/TraG conjugation system remains of the T4SS) suggest that it should be considered as a new lineage clade (L5) within the Bartonella genus.

Bartonella spp. detection in laelapid (Mesostigmata: Laelapidae) mites collected from small rodents in Lithuania

The genus Bartonella contains facultative Gram-negative intracellular bacteria from the family Bartonellaceae that can cause diseases in humans and animals. Various Bartonella species have been detected in rodents' ectoparasites, such as fleas, ticks, mites, and lice. However, the role of laelapid mites (Mesostigmata: Laelapidae) as carriers of Bartonella spp. needs to be confirmed. We aimed to investigate the presence of Bartonella spp. in laelapid mites collected from small rodents in Lithuania using real-time PCR targeting the transfer-messenger RNA/tmRNA (ssrA) gene and to characterize Bartonella strains using nested PCR and sequence analysis of the 16S-23S rRNA intergenic transcribed spacer region (ITS). A total of 271 laelapid mites of five species (Laelaps agilis, Haemogamasus nidi, Eulaelaps stabularis, Myonyssus gigas, and Hyperlaelaps microti) were collected from five rodent species (Apodemus flavicollis, Apodemus agrarius, Clethrionomys glareolus, Micromys minutus, and Microtus oeconomus) during 2015-2016. Bartonella DNA was detected in three mite species L. agilis, M. gigas, and Hg. nidi with an overall prevalence of 11.4%. Sequence analysis of the 16S-23S rRNA ITS region revealed the presence of Bartonella taylorii in L. agilis, Hg. nidi, and M. gigas, and Bartonella grahamii in L. agilis. Our results suggest that laelapid mites are involved in the maintenance of rodent-associated Bartonella spp. in nature. To the best of the authors' knowledge, this is the first study to demonstrate the presence of Bartonella spp. DNA in laelapid mites from small rodents.

Host specificity and genetic diversity of Bartonella in rodents and shrews from Eastern China

Bartonella are vector-borne gram-negative facultative intracellular bacteria causing emerging infectious diseases worldwide, and two thirds of known Bartonella species are carried by rodents. We captured rodents, shrews and rodent ectoparasitic mites in rural areas of Qingdao City, Shandong Province, China from 2012 to 2021 and used the animal spleen tissues for the PCR amplification of Bartonella gltA and rpoB genes. PCR showed 9.4% (40/425) rodents, and 5.1% (12/235) shrews were positive for Bartonella. Seven Bartonella species including three novel species were identified in five rodent species and one shrew species, indicating the abundance and genetic diversity of Bartonella in rodents and shrews. The infection rate of each Bartonella species in the animal species was as below: novel Candidatus Bartonella crocidura in shrews Crocidura lasiura (5.1%, 12/235); novel Candidatus Bartonella cricetuli in hamsters Tscherskia triton (20%, 9/45); novel Candidatus Bartonella muris in striped field mice Apodemus agrarius (4.2%, 7/168) and house mice Mus musculus (1.5%, 2/135); Bartonella fuyuanensis in striped field mice (8.9%, 15/168) and house mice (0.7%, 1/135); Bartonella rattimassiliensis and Bartonella tribocorum in brown rats Rattus norvegicus (6.7%, 3/45 and 4.2%, 2/45, respectively); Bartonella queenslandensis in Chinese white-bellied rat Niviventer confucianus (12.5%, 1/8). These results suggest that Bartonella infected a variety of rodent and shrew species with high infection rate, but each Bartonella specie is restricted to infect only one or a few genetically closely related rodent species. In addition, Candidatus Bartonella cricetuli, Candidatus Bartonella muris and Bartonella coopersplainsensis were found in chigger Walchia micropelta (33.3%, 3/9), and B. fuyuanensis were found in chigger Leptotrombidium intermedium (4.1%, 1/24), indicating chiggers may be reservoirs of Bartonella. In conclusion, abundant genetic diversified Bartonella species are found to infect rodents, shrews and chiggers, but each Bartonella species has a strict rodent animal host specificity; and chigger mites may play a role in Bartonella transmission.

Serological evidence of exposure to Bartonella sp. in dogs with suspected vector-borne diseases, toxoplasmosis and neosporosis

Bartonellosis is a vector-borne zoonotic disease with worldwide distribution that infect a broad spectrum of mammalian species. Despite the recent studies carried out in Brazil, information regarding Bartonella in dogs are scarce. Therefore, we performed a retrospective study to investigate the exposure to Bartonella sp. in dogs by indirect immunofluorescence assay (IFA). Three hundred and thirty-five archived serum samples from dogs previously tested for vector-borne pathogens, Toxoplasma gondii, and Neospora caninum were screened for the presence of IgG antibodies to Bartonella sp. All dogs originated from the Metropolitan region of Ribeirão Preto, northeast of the State of São Paulo. Twenty-eight samples (8.3%) were positive for Bartonella sp. at the cut-off of 64. Among the 28 seropositive samples for Bartonella sp., 16 (57.1%) were also seropositive for Ehrlichia canis, 12 (42.8%) for Babesia vogeli, five (17.8%) for T. gondii and three (10.7%) for L. infantum and N. caninum. Our results demonstrated that dogs sampled were exposed to Bartonella sp. Since all the animals sampled in the present study were from private owners, our findings demonstrate that these people may also be exposed to Bartonella sp. Further studies designed to assess whether the infection by other arthropod-borne pathogens such as B. vogeli and E. canis are risk factors for Bartonella infection are needed.

First Report of Bartonella spp. in Marsupials from Brazil, with a Description of Bartonella harrusi sp. nov. and a New Proposal for the Taxonomic Reclassification of Species of the Genus Bartonella

The genus Bartonella (Rhizobiales: Bartonellaceae) encompasses facultative intracellular Gram-negative alphaproteobacteria that parasitize mainly erythrocytes and endothelial cells, as well as macrophages, monocytes and dendritic cells. Although they can infect numerous mammal species and arthropod vectors worldwide, reports of Bartonella infections in marsupials are scarce. In fact, such agents have only been detected in marsupials and/or associated ectoparasites in Australia and the United States of America until the present moment. The present study aimed to isolate and characterize molecularly, morphologically and phenotypically Bartonella infecting free-living marsupials sampled in the Brazilian Pantanal, the largest wetland in South America. Two marsupials were captured in December 2018 and six marsupials in February 2019, totaling eight small mammals sampled: five (62.5%) Thylamys macrurus and three (37.5%) Monodelphis domestica. All blood samples were submitted to qPCR for Bartonella spp. based on the nuoG gene, a pre-enrichment liquid culture and a chocolate agar solid culture. Bartonella sp. was isolated from 3 T. macrurus and one M. domestica. One Bartonella isolate obtained from a T. macrurus blood sample (strain 117A) that showed to be closely related to the Bartonella vinsonii complex and Bartonella machadoae was selected for whole genome sequencing using a hybrid approach based on Illumina NovaSeq and Nanopore sequencing platforms. This strain showed a genome of 2.35 Mbp, with an average C + G content of 38.8%, coding for 2013 genes, and a 29 kb plasmid with an average C + G content of 34.5%. In addition, this strain exhibited an average nucleotide identity (ANI) of 85% with Bartonella species belonging to the B. vinsonii group and 91% with B. machadoae. Phylogenomic analysis based on 291 protein coding genes shared by the genomes of 53 Bartonella species positioned this strain closely to B. machadoae. This new isolated species was named Bartonella harrusi sp. nov., which was characterized as having small capnophilic, microaerophilic and aerobic rods with an absence of pili and flagella. In conclusion, the present work describes the biochemical, phenotypic and genomic characteristics of Bartonella harrusi, a new species isolated from the T. macrurus blood samples of the Brazilian Pantanal. Finally, a review of the taxonomic classification of members of the genus Bartonella is proposed, based on the ANI values accessed by whole genome sequencing analyses.

Culling of Urban Norway Rats and Carriage of Bartonella spp. Bacteria, Vancouver, British Columbia, Canada

We investigated the effects of culling on Bartonella spp. bacteria carriage among urban rats in Canada. We found that the odds of Bartonella spp. carriage increased across city blocks except those in which culling occurred. Removing rats may have prevented an increase in Bartonella spp. prevalence, potentially lowering human health risks.

First report of three novel Bartonella species isolated in rodents and shrews from nine provinces of Thailand

Background and Aim:

Bartonella spp. are Gram-negative zoonotic bacteria that are transmitted to humans by several types of animal hosts, including rodents. Several studies have been conducted on the prevalence of Bartonella infections in rodents. However, the risk of rodent-associated Bartonella spp. infection in humans remains unclear. This study aimed to estimate the prevalence and genetic heterogeneity of Bartonella spp. in rodents and shrews from nine provinces of Thailand using culture and molecular techniques.

Materials and Methods:

A total of 860 blood samples from rodents and shrews across nine provinces of Thailand were collected from January 2013 to June 2016. Bartonella spp. were isolated from all samples using conventional culture techniques and polymerase chain reaction. Phylogenetic tree analysis was used to align the Bartonella sequences obtained from this study.

Results:

The prevalence of Bartonella spp. in rodents and shrews was 11.5% (99/860, 95% confidence interval: 9.38–13.64%). The following nine species of Bartonella were detected: Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella queenslandensis, Bartonella elizabethae, Bartonella chanthaburi spp. nov., Bartonella satun spp. nov., Bartonella coopersplainsensis, Bartonella ranong spp. nov., and Bartonella henselae. The prevalence of Bartonella-positive animals differed significantly among provinces.

Conclusion:

To the best of our knowledge, the three novel Bartonella spp. isolated from rodents and shrews across Thailand were detected for the first time in this study. Further studies on the epidemiology of Bartonella infection in rodents and its interaction with human health should be conducted in accordance with the Thai government’s “One Health” approach to humans, animals, and the environment.

Epidemiology and Genetic Diversity of Bartonella in Rodents in Urban Areas of Guangzhou, Southern China

Bartonella spp. are gram-negative bacteria that can infect a wide spectrum of mammals. Rodents are considered to be the natural reservoir of many Bartonella species that are transmitted by various blood-sucking arthropods. The close contact between rodents and humans in urban areas increased the chance of transmitting rodent-borne Bartonella to humans. Investigation of the epidemiological characteristics of Bartonella infection in rodents is of great significance for the prevention and control of human Bartonellosis. In this study, rodents were captured to monitor the prevalence of Bartonella in urban areas of Guangzhou city. Six official or candidate species of Bartonella, including two confirmed zoonotic species, were detected with an overall prevalence of 6.4% in rodents captured herein. In addition, Rattus norvegicus was the predominant host species for Bartonella infection, and B. queenslandensis was the dominant species circulating in rodents in these areas. These results provide insights into the prevalence and genetic diversity of Bartonella species circulating in rodents in the urban areas of Guangzhou, and also urged the surveillance of rodent-associated Bartonella species in these areas.

Diversity and distribution of ectoparasite taxa associated with Micaelamys namaquensis (Rodentia: Muridae), an opportunistic commensal rodent species in South Africa

South Africa boasts a rich diversity of small mammals of which several are commensal and harbour parasites of zoonotic importance. However, limited information is available on the parasite diversity and distribution associated with rodents in South Africa. This is particularly relevant for Micaelamys namaquensis (Namaqua rock mouse), a regionally widespread and locally abundant species that is often commensal. To address the paucity of data, the aims of the study were to record the ectoparasite diversity associated with M. namaquensis and develop distribution maps of lice and mites associated with M. namaquensis and other rodents in South Africa. Micaelamys namaquensis individuals (n = 216) were obtained from 12 localities representing multiple biomes during 2017–2018. A total of 5591 ectoparasites representing 5 taxonomic groups – fleas, lice, mesostigmatid mites, chiggers and ticks was recorded. These consisted of at least 57 taxa of which ticks were the most speciose (20 taxa). Novel contributions include new host and locality data for several ectoparasite taxa and undescribed chigger species. Known vector species were recorded which included fleas (Ctenocephalides felis, Dinopsyllus ellobius and Xenopsylla brasiliensis) and ticks (Haemaphysalis elliptica, Rhipicephalus appendiculatus and Rhipicephalus simus). Locality records indicate within-taxon geographic differences between the 2 louse species and the 2 most abundant mite species. It is clear that M. namaquensis hosts a rich diversity of ectoparasite taxa and, as such, is an important rodent species to monitor in habitats where it occurs in close proximity to humans and domestic animals.

Prevalence and diversity of small rodent-associated Bartonella species in Shangdang Basin, China

The aim of this study was to investigate the occurrence and molecular characteristics of Bartonella infections in small rodents in the Shangdang Basin, China. Small rodents were captured using snap traps, and their liver, spleen, and kidney tissues were harvested for Bartonella detection and identification using a combination of real-time PCR of the ssrA gene (296 bp) and conventional PCR and sequencing of the gltA gene (379 bp). Results showed that 55 of 147 small rodents to be positive for Bartonella, with a positivity rate of 37.41%, and 95% confidence interval of 29.50%- 45.33%. While the positivity rate across genders (42.62% in males and 33.72% in females, χ2 = 1.208, P = 0.272) and tissues (28.57% in liver, 33.59% in spleen, and 36.76% in kidney, χ2 = 2.197, P = 0.333) of small rodents was not statistically different, that in different habitats (5.13% in villages, 84.44% in forests, and 54.17% in farmlands, χ2 = 80.105, P<0.001) was statistically different. There were 42 Bartonella sequences identified in six species, including 30 B. grahamii, three B. phoceensis, two B. japonica, two B. queenslandensis, one B. fuyuanensis and four unknown Bartonella species from Niviventer confucianus, Apodemus agrarius and Tscherskia triton. In addition to habitat, Bartonella species infection could be affected by the rodent species as well. Among the Bartonella species detected in this area, B. grahamii was the dominant epidemic species (accounting for 71.43%). B. grahamii exhibited four distinct clusters, and showed a certain host specificity. In addition, 11 haplotypes of B. grahamii were observed using DNASP 6.12.03, among which nine haplotypes were novel. Overall, high occurrence and genetic diversity of Bartonella were observed among small rodents in the Shangdang Basin; this information could potentially help the prevention and control of rodent-Bartonella species in this area.

Genomic structural plasticity of rodent-associated Bartonella in nature

Rodent‐associated Bartonella species have shown a remarkable genetic diversity and pathogenic potential. To further explore the extent of the natural intraspecific genomic variation and its potential role as an evolutionary driver, we focused on a single genetically diverse Bartonella species, Bartonella krasnovii, which circulates among gerbils and their associated fleas. Twenty genomes from 16 different B. krasnovii genotypes were fully characterized through a genome sequencing assay (using short and long read sequencing), pulse field gel electrophoresis (PFGE), and PCR validation. Genomic analyses were performed in comparison to the B. krasnovii strain OE 1–1. While, single nucleotide polymorphism represented only a 0.3% of the genome variation, structural diversity was identified in these genomes, with an average of 51 ± 24 structural variation (SV) events per genome. Interestingly, a large proportion of the SVs (>40%) was associated with prophages. Further analyses revealed that most of the SVs, and prophage insertions were found at the chromosome replication termination site (ter), suggesting this site as a plastic zone of the B. krasnovii chromosome. Accordingly, six genomes were found to be unbalanced, and essential genes near the ter showed a shift between the leading and lagging strands, revealing the SV effect on these genomes. In summary, our findings demonstrate the extensive genomic diversity harbored by wild B. krasnovii strains and suggests that its diversification is initially promoted by structural changes, probably driven by phages. These events may constantly feed the system with novel genotypes that ultimately lead to inter‐ and intraspecies competition and adaptation.

Bartonella machadoae sp. nov. isolated from wild rodents in the Pantanal wetland

It has been estimated that 75% of emerging infectious diseases comprise zoonoses, whose majority have free-living animals as reservoirs and are mainly transmitted by arthropod vectors. Although rodents represent important Bartonella reservoirs, there are few studies on the genotypic characterization of Bartonella species commonly found in this taxon and from different Brazilian biomes. Therefore, the present study aimed to investigate the occurrence, isolate and molecularly, morphologically and phenotypically characterize a new Bartonella species infecting free-living rodents sampled in the Brazilian Pantanal, the largest wetland in South America. For this purpose, 129 free-living rodents (79 Thrichomys fosteri, 4 Clyomys laticeps, and Oecomys mamorae) were captured. While blood samples were collected from 57 T. fosteri, 4 C. laticeps and 32 O. mamorae; spleen samples were collected from 22 T. fosteri and 14 O. mamorae. Blood and spleen samples were submitted to a qPCR for Bartonella spp. targeting the nuoG gene, using DNA samples extracted directly from blood/spleen, after passage in pre-enrichment liquid culture, and from colonies obtained from solid culture on chocolate agar. Combining all techniques, occurrence of 24.8% for Bartonella sp. was found among the sampled rodents. One Bartonella isolate (strain 56A) obtained from a T. fosteri's blood sample was closely related to the Bartonella vinsonii complex and selected for Whole Genome Sequencing (WGS) hybrid approach using Illumina NovaSeq and Nanopore sequencing platforms. This strain exhibits a circular 2.7 Mbp genome with an average C+G content of 39% and encoding to 2239 genes. In the phylogenomics based on 291 shared protein-coding genes, this strain was positioned in a unique clade, closely related to Bartonella vinsonii subsp. vinsonii, B. vinsonii subsp. berkhoffii and B. visonii subsp. arupensis. An Average Nucleotide Identity of 85% was found between the obtained isolate and Bartonella species belonging to B. vinsonii complex. These findings supported the separation of this strain, now formally named as Bartonella machadoae sp. nov., from the Bartonella vinsonii complex. In addition, Bartonella machadoae sp. nov. was characterized by capnophilic, microaerophilic and aerobic small rods with absence of pili and flagella. Phylogenetic and distance analyses based on five concatenated molecular markers suggest that Bartonella machadoae may parasite rodents from different Brazilian biomes. In conclusion, we described biochemical, phenotypic and genomic characteristics of Bartonella machadoae nov. sp. isolated from blood samples of T. fosteri rodents from the Brazilian Pantanal.

Epidemiological characteristics and genetic diversity of Bartonella species in rodents from southeastern China

Rodents are the primary hosts of Bartonella species and carry more than 22 Bartonella species. However, the information on epidemiological characteristics and genetic diversity of Bartonella species in rodents in southeastern China is limited. From 2015 to 2020, 1,137 rodents were captured. Bartonella-positive DNA was detected in 14.9% (169/1,137) of rodents by PCR for both the ssrA and gltA genes. A highest Bartonella prevalence was detected in Apodemus agrarius (33.5%) and lowest in B. indica (1.8%). The probability of Bartonella infection in summer (20.1%) was higher than in spring (14.6%; p = .011, OR = 1.756). Sequencing and phylogenetic analysis revealed that nine known Bartonella species were identified in rodents, including B. tribocorum, B. grahamii, B. rattimassiliensis, B. queenslandensis, B. elizabethae, B. phoceensis, B. coopersplainsensis, B. japonica and B. rochalimae. In our study, Bartonella species exhibited a strong association with their hosts. Zoonotic B. tribocorum, B. grahamii, B. elizabethae and B. rochalimae were found in synanthropic rodent species in southeastern China, which pose a potential threat to the public health. To prevent the spread of zoonotic Bartonella species to humans, preventive and control measures should be implemented, and more research is needed to confirm the pathogen's association with human disease.

Detection and genetic diversity of Bartonella species in small mammals from the central region of the Qinghai-Tibetan Plateau, China

In this study, we aimed to investigate the prevalence and molecular characteristics of Bartonella infections in small mammals from the central region of the Qinghai-Tibetan Plateau. Toward this, small mammals were captured using snap traps in Yushu City and Nangqian County, West China, and the spleen tissue was used for Bartonella culture. The suspected positive colonies were evaluated using polymerase chain reaction (PCR) amplification and by sequencing the citrate synthase (gltA) gene. We discovered that 31 out of the 103 small mammals tested positive for Bartonella, with an infection rate of 30.10%. Sex differences between the mammals did not result in a significant difference in infection rate (χ² = 0.018, P = 0.892). However, there was a significant difference in infection rates in different small mammals (Fisher’s exact probability method, P = 0.017) and habitats (χ² = 7.157, P = 0.028). Additionally, 31 Bartonella strains belonging to three species were identified, including B. grahamii (25), B. japonica (4) and B. heixiaziensis (2), among which B. grahamii was the dominant epidemic strain (accounting for 80.65%). Phylogenetic analyses showed that most of the B. grahamii isolates identified in this study may be closely related to the strains isolated from Japan and China. Genetic diversity analyses revealed that B. grahamii strains had high genetic diversity, which showed a certain host and geographical specificity. The results of Tajima’s test suggested that the B. grahamii followed the progressions simulated by a neutral evolutionary model in the process of evolution. Overall, a high prevalence and genetic diversity of Bartonella infection were observed in small mammals in the central region of the Qinghai-Tibetan Plateau. B. grahamii as the dominant epidemic strain may cause diseases in humans, and the corresponding prevention and control measures should be taken into consideration in this area.

Serological and Molecular Detection of Bartonella henselae in Cats and Humans From Egypt: Current Status and Zoonotic Implications

Bartonellosis is a vector-borne zoonotic disease caused by the intracellular bacterium of genus Bartonella. The disease has a worldwide distribution and cats represent the major reservoir of this disease. Despite its global distribution, very limited previous studies have investigated the occurrence of bartonellosis in cats and their owners in Egypt. In an endeavor to explore this topic, we investigated the occurrence of Bartonella henselae (B. henselae) infection in 225 samples (blood, saliva, and claw) obtained from 75 healthy cats in Upper Egypt. These samples were routinely obtained during veterinary clinic visits. This study also involved an examination of 100 humans, including cat owners and people with a history of contact with cats. Attempted isolation and identification of B. henselae in cats were also performed. Furthermore, PCR was performed for molecular identification of B. henselae in blood samples from cats. Meanwhile, an immunofluorescent assay was performed to study the seroprevalence of B. henselae infection in humans. In this study, B. henselae could not be isolated from any of the examined blood, saliva, or claw samples from cats. Interestingly, B. henselae was identified molecularly in 8% (6/75) of blood samples from cats. The seroprevalence of B. henselae in humans was 46% and its occurrence was higher in females (46.6%) than in males (41.7%) (P = 0.748). B. henselae infection was higher among cat owners [51.4% (19/37)] than among people with a history of contact with cats [42.9% (27/63)] (P = 0.410). Infection was higher in rural regions [79.5% (31/39)] than in urban regions [24.6% (15/61)] (P < 0.001). Collectively, this data provide interesting baseline information about the occurrence of B. henselae in cats and humans in Upper Egypt, which reflects the potential zoonotic transmission of this bacterium. Future study is mandatory to explore the occurrence of B. henselae in major reservoirs in Egypt.

Eco-epidemiological screening of multi-host wild rodent communities in the UK reveals pathogen strains of zoonotic interest

Wild rodent communities represent ideal systems to study pathogens and parasites shared among sympatric species. Such studies are useful in the investigation of eco-epidemiological dynamics, improving disease management strategies and reducing zoonotic risk. The aim of this study was to investigate pathogen and parasites shared among rodent species (multi-host community) in West Wales in an area where human/wildlife disease risk was not previously assessed. West Wales is predominantly rural, with human settlements located alongside to grazing areas and semi-natural landscapes, creating a critical human-livestock-wildlife interface. Ground-dwelling wild rodent communities in Wales were live-trapped and biological samples - faeces and ectoparasites - collected and screened for a suite of pathogens and parasites that differ in types of transmission and ecology. Faecal samples were examined to detect Herpesvirus, Escherichia coli, and Mycobacterium microti. Ticks and fleas were collected, identified to species based on morphology and genetic barcodes, and then screened for Anaplasma phagocytophilum, Babesia microti, Borrelia burgdorferi sensu lato, and Bartonella sp. All the pathogens and parasites screened pose a characteristic epidemiological challenge, such as variable level of generalism, unknown zoonotic potential, and lack of data. The results showed that the bank vole Myodes glareolus had the highest prevalence of all pathogens and parasites. Higher flea species diversity was detected than in previous studies, and at least two Bartonella species were found circulating, one of which has not previously been detected in the UK. These key findings offer new insights into the distribution of selected pathogen and parasites and subsequent zoonotic risk, and provide new baselines and perspectives for further eco-epidemiological research.

Emerging rodent-associated Bartonella: a threat for human health?

Background

Species of the genus Bartonella are facultative intracellular alphaproteobacteria with zoonotic potential. Bartonella infections in humans range from mild with unspecific symptoms to life threatening, and can be transmitted via arthropod vectors or through direct contact with infected hosts, although the latter mode of transmission is rare. Among the small mammals that harbour Bartonella spp., rodents are the most speciose group and harbour the highest diversity of these parasites. Human–rodent interactions are not unlikely as many rodent species live in proximity to humans. However, a surprisingly low number of clinical cases of bartonellosis related to rodent-associated Bartonella spp. have thus far been recorded in humans.

Methods

The main purpose of this review is to determine explanatory factors for this unexpected finding, by taking a closer look at published clinical cases of bartonellosis connected with rodent-associated Bartonella species, some of which have been newly described in recent years. Thus, another focus of this review are these recently proposed species.

Conclusions

Worldwide, only 24 cases of bartonellosis caused by rodent-associated bartonellae have been reported in humans. Possible reasons for this low number of cases in comparison to the high prevalences of Bartonella in small mammal species are (i) a lack of awareness amongst physicians of Bartonella infections in humans in general, and especially those caused by rodent-associated bartonellae; and (ii) a frequent lack of the sophisticated equipment required for the confirmation of Bartonella infections in laboratories that undertake routine diagnostic testing. As regards recently described Bartonella spp., there are presently 14 rodent-associated Candidatus taxa. In contrast to species which have been taxonomically classified, there is no official process for the review of proposed Candidatus species and their names before they are published. This had led to the use of malformed names that are not based on the International Code of Nomenclature of Prokaryotes. Researchers are thus encouraged to propose Candidatus names to the International Committee on Systematics of Prokaryotes for approval before publishing them, and only to propose new species of Bartonella when the relevant datasets allow them to be clearly differentiated from known species and subspecies.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05162-5.

Detection of Potential Zoonotic Bartonella Species in African Giant Rats (Cricetomys gambianus) and Fleas from an Urban Area in Senegal

Bartonellae are bacteria associated with mammals and their ectoparasites. Rodents often host different species of Bartonella. The aim of this study was to investigate the presence of Bartonella spp. in African giant pouched rats (Cricetomys gambianus) and their ectoparasites in Dakar, Senegal. In 2012, 20 rats were caught, and their fleas were identified. DNA was extracted from 170 selected fleas and qPCR was carried out to detect Bartonella spp. Subsequently, a Bartonella culture was performed from the rat blood samples and the isolated strains (16S rRNA, rpoB, ftsZ and ITS3) were genotyped. A total of 1117 fleas were collected from 19 rats and identified as Xenopsylla cheopis, the tropical rat flea. Bartonella DNA was detected in 148 of 170 selected fleas (87.1%). In addition, Bartonella strains were isolated from the blood of 17 rats (85%). According to Bartonella gene-sequence-based criteria for species definition, the isolated strains were identified as B. massiliensis (four strains) and two potential new species related to the zoonotic B. elizabethae. In this paper, these potentially new species are provisionally called Candidatus Bartonella militaris (11 strains) and Candidatus Bartonella affinis (two strains) until their description has been completed. Cricetomys gambianus and its fleas could constitute a public health risk in Dakar due to the high prevalence of Bartonella infection reported.

Molecular Detection of Bartonella Species in Rodents Residing in Urban and Suburban Areas of Central Thailand

Bartonella spp. are Gram-negative zoonotic bacteria transmitted to humans via various blood-sucking arthropods. Rodents have been identified as reservoir hosts of several zoonotic pathogens, including Bartonella spp. In Thailand, studies of Bartonella spp. in rodents from urban areas are limited; thus, a study in this area is necessary. The objectives of this study were to detect Bartonella spp. in rodents in Thailand and to compare the species’ distribution across different areas. In total, 70 blood samples from rodents in urban and suburban areas were tested for Bartonella spp. using a conventional polymerase chain reaction that targeted the citrate synthase (gltA) gene. All Bartonella-positive sequences were analyzed using polymorphism in order to build a phylogenetic tree. Approximately 38% of the rodents studied contained Bartonella DNA. Both Rattus exulans (Pacific rat) and R. tanezumi (Asian house rat) contained Bartonella spp. Four species of Bartonella were detected in blood samples: B. tribocorum, B. phoceensis, B. grahamii, and B. rattimassiliensis. In addition, eight Pacific rats contained the B. kosoyi–B. tribocorum complex. Bartonella phoceensis and B. tribocorum–B. kosoyi complexes were found in a specific habitat (p < 0.05). Interestingly, only seven haplotypes were identified in the sequences analyzed, and only haplotype A was found in both rodent species. Finally, a monitoring program for zoonotic Bartonella infection, especially the B. kosoyi–B. tribocorum complex, B. phoceensis, B. grahamii, and B. rattimassiliensis should be established, especially in high-risk areas.

Molecular identification and genetic diversity of Bartonella spp. in 24 bat species from Thailand

The study of bacterial zoonoses has been under-pursued despite the fact that bacteria cause the majority of zoonotic diseases, of which 70% have a wildlife origin. More Bartonella species are being identified as the cause of human diseases, and several of them have been linked to domestic and wild animals. Bats are outstanding reservoirs for Bartonella species because of their wide distribution, mobility, roosting behaviour, and long life span. Here, we carried out a PCR-based survey on bats that were collected from 19 sampling sites in eight provinces of Thailand from February 2018 to April 2021. Bartonella infection was investigated in a total of 459 bats that belong to 24 different bat species (21 species of which had never been previously studied in Thailand). PCR diagnostics revealed that 115 out of 459 (25.5%) blood samples tested positive for Bartonella. The nucleotide identities of the Bartonella 16S rRNA sequences in this study were between 95.78-99.66% identical to those of known zoonotic species (Bartonella ancashensis, Bartonella henselae, Bartonella bacilliformis and Bartonella australis) as well as to an unidentified Bartonella spp. In addition, the citrate synthase (gltA) and RNA polymerase-beta subunit (rpoB) genes of Bartonella were sequenced and analyzed in positive samples. The gltA and rpoB gene sequences from Hipposideros gentilis and Rhinolophus coelophyllus bat samples showed low nucleotide identity (<95%) compared to those of the currently deposited sequences in the GenBank database, indicating the possibility of new Bartonella species. The phylogenetic inference and genetic diversity were generated and indicated a close relationship with other Bartonella species previously discovered in Asian bats. Overall, the current study demonstrates the primary evidence pointing to a potential novel Bartonella species in bats. This discovery also contributes to our current understanding of the geographical distribution, genetic diversity, and host ranges of bat-related Bartonella.