Bartonella species in small mammals and their potential vectors in Asia

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.

Bartonellosis in World Health Organization Eastern Mediterranean Region, a systematic review and meta-analysis

Bartonella is a vector-borne zoonotic pathogen, which could also be transmitted directly and cause a variety of clinical illnesses. This study aimed to investigate the prevalence of Bartonella in countries in the WHO Eastern Mediterranean Region (WHO-EMR) region. We searched using the keywords Bartonella and the name of each country in the WHO-EMR in databases such as PubMed, ISI (Web of Science), Scopus, and Google Scholar, with a publication date range of 1990-2022 and limited to English articles. We evaluated the quality of the studies using the STROBE 6-item checklist and used the random effects model to integrate the findings of the included studies. A total of 45 papers out of 240 were included in the analysis. The results showed the prevalence of Bartonella infection among endocarditis patients was 3.8% (95% CI: 0.2-7.4) and the seroprevalence of Bartonella among other people was 27.5% (95% CI: 13.5-41.5). The overall prevalence of Bartonella spp. among animals, as determined by molecular, serological, and culture methods, was 11.9% (95% CI: 5.7-18.2), 38.9% (95% CI: 27.5-50.2), and 1.7% (95% CI: 0.5-2.9), respectively. Furthermore, the prevalence of Bartonella spp. in ectoparasites was 3.9% (95% CI: 3.5-5.2), with fleas (6.2%) showing a higher prevalence compared to lice (4.9%) and ticks (1.0%). The detection of Bartonella in all animal and ectoparasites species and human populations in the WHO-EMR with prevalence ranging from 0.3% to 23% is concerning, emphasizes the importance of conducting more comprehensive studies to gain a deeper understanding of the spread of Bartonella in these areas.

New host record and redescription of Amblyomma cordiferum nymphs and larvae infesting Malaysian house rats (Rattus rattus diardii) in Peninsular Malaysia, with molecular evidence of Rickettsia, Borrelia, and Bartonella

Nymphal and larval Amblyomma cordiferum ticks, a relatively rare species, were collected from the Malaysian house rat (Rattus rattus diardii) in Peninsular Malaysia. Redescription and molecular analysis of nymphs and larvae, based on the 12S rRNA, 16S rRNA, and COI genes, revealed divergence from A. cordiferum in Taiwan, suggesting that the Taiwanese tick specimens may represent a different taxon. Molecular analysis of the pathogens in these specimens revealed three sequences of Rickettsia closely related or identical to Rickettsia raoultii (99.71-100%), two sequences of relapsing fever Borrelia identical to Borrelia theileri, and four sequences of Bartonella identical to Bartonella phoceensis. This study also identifies a new host record for A. cordiferum in R. r. diardii and reports the first detection of Rickettsia, Borrelia, and Bartonella in this tick species.

Dermacentor (Indocentor) auratus Supino 1897: Potential geographic range, and medical and veterinary significance

Dermacentor (Indocentor) auratus Supino, 1897 occurs in many regions of Southeast Asia and South Asia. In many regions of Southeast Asia and South Asia, targeted tick sampling and subsequent screening of collected D. auratus ticks have detected pathogenic bacteria and viruses in D. auratus. These disease-causing pathogens that have been detected in D. auratus include Anaplasma, Bartonella, Borrelia, Rickettsia (including spotted fever group rickettsiae), African swine fever virus, Lanjan virus, and Kyasanur forest disease virus. Although D. auratus predominantly infests wild pigs, this tick is also an occasional parasite of humans and other animals. Indeed, some 91 % of human otoacariasis cases in Sri Lanka were due to infestation by D. auratus. With the propensity of this tick to feed on multiple species of hosts, including humans, and the detection of pathogenic bacteria and viruses from this tick, D. auratus is a tick of medical, veterinary, and indeed zoonotic concern. The geographic range of this tick, however, is not well known. Therefore, in the present paper, we used the species distribution model, BIOCLIM, to project the potential geographic range of D. auratus, which may aid pathogen and tick-vector surveillance. We showed that the potential geographic range of D. auratus is far wider than the current geographic distribution of this tick, and that regions in Africa, and in North and South America seem to have suitable climates for D. auratus. Interestingly, in Southeast Asia, Borneo and Philippines also have suitable climates for D. auratus, but D. auratus has not been found in these regions yet despite the apparent close proximity of these regions to Mainland Southeast Asia, where D. auratus occurs. We thus hypothesize that the geographic distribution of D. auratus is largely dependent on the movement of wild pigs and whether or not these wild pigs are able to overcome dispersal barriers. We also review the potential pathogens and the diseases that may be associated with D. auratus and provide an updated host index for this tick.

Characterizing the blood microbiota of omnivorous and frugivorous bats (Chiroptera: Phyllostomidae) in Casanare, eastern Colombia

Bats are known reservoirs of seemingly-innocuous pathogenic microorganisms (including viruses, bacteria, fungi, and protozoa), which are associated with triggering disease in other zoonotic groups. The taxonomic diversity of the bats' microbiome is likely associated with species-specific phenotypic, metabolic, and immunogenic capacities. To date, few studies have described the diversity of bat blood microbial communities. Then, this study used amplicon-based next generation sequencing of the V4 hypervariable region of the 16S-rRNA gene in blood samples from omnivorous (n = 16) and frugivorous (n = 9) bats from the department of Casanare in eastern Colombia. We found the blood microbiota in bats to be composed of, among others, Bartonella and Mycoplasma bacterial genera which are associated with various disease phenotypes in other mammals. Furthermore, our results suggest that the bats' dietary habits might determine the composition and the persistence of some pathogens over others in their bloodstream. This study is among the first to describe the blood microbiota in bats, to reflect on co-infection rates of multiple pathogens in the same individual, and to consider the influence of diet as a factor affecting the animal's endogenous microbial community.

Molecular epidemiology of Bartonella species from sympatric mammals collected in urban and rural areas of Punjab, Pakistan

Bartonella can infect a variety of mammals including humans and has been detected in the Americas, Europe, Africa, and Asia. Roughly two-thirds of identified Bartonella species are found and maintained in rodent reservoirs, with some of these species linked to human infections. Rodents (N=236) were caught from the Sahiwal division of Punjab, Pakistan and tested for Bartonella using PCR targeting gltA and rpoB genes, followed by sequencing of rpoB-positive samples. Genetic relatedness to other published Bartonella spp. rpoB gene sequences were examined using BLAST and phylogenetic analysis. Overall, 7.62% (18/236) of rodents were positive for both gltA and rpoB fragments. Rattus rattus and R. norvegicus had 7.94% (12/151) and 7.05% (6/85) positivity rates for Bartonella DNA, respectively. Phylogenetic analysis revealed a close relatedness between Bartonella spp. from Pakistan to Bartonella spp. from China, Nepal, and Malaysia. This study is the first reported detection of Bartonella spp. in R. rattus and R. norvegicus from the Sahiwal area of Punjab, Pakistan.

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.

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 of zoonotic Bartonella species in ticks and fleas parasitizing free-ranging cats and dogs residing in temples of Bangkok, Thailand

Bartonellosis is a vector-borne disease caused by intraerythrocytic bacteria known as Bartonella spp. The potential vectors that transmit Bartonella spp. are fleas, ticks, sand flies, and lice. Several Bartonella spp. cause diseases in humans; however, there is few molecular evidence of Bartonella spp. in vectors in Thailand. The objectives of this study were to investigate Bartonella spp. and to evaluate the spatial distribution of Bartonella spp. prevalence in the ectoparasites parasitizing free-ranging cats and dogs in temple clusters of Bangkok, Thailand. In total, 343 ectoparasites were studied to extract their genomic DNA. Species of all specimens were identified using an identification key and conventional polymerase chain reaction (cPCR) was applied to confirm flea and tick species. Extracted DNA samples were processed using primers that targeted the gltA, rpoB, ftsZ, and ribC genes of Bartonella spp. Then, PCR-positive amplicons were sequenced and a phylogenetic tree was constructed. Recorded data were statistically analyzed using descriptive statistics, the chi-square test, Fisher's exact test, and the odds ratio. Area data were analyzed and a prevalence distribution map was plotted. The major parasitizing ticks and fleas in this study were Rhipicephalus sanguineus and Ctenocephalides felis, respectively. Overall, the prevalence of Bartonella spp. in ectoparasites was 7.00%. The gltA amplicons revealed the presence of B. henselae (4.78%) and B. clarridgeiae (4.78%) in C. felis, and B. koehlerae (1.25%) and B. phoceensis (1.25%) in R. sanguineus. Bartonella DNA was encountered in 16/39 (41.03%) districts and 28.57% of the temple clusters. Bang Khun Thian district had the highest positive proportion and Bang Bon district showed co-evidence of different Bartonella species. In addition, the intervening zones were a risk factor of Bartonella (p < 0.05), and the distribution map showed a scattered pattern of Bartonella-positive clusters. Finally, fleas showed to be important vector reservoirs for Bartonella spp., especially zoonotic species, however, experimental studies are needed to prove the Bartonella transmission in ticks.

High prevalence and diversity of Bartonella in small mammals from the biodiverse Western Ghats

Bartonella species are recognized globally as emerging zoonotic pathogens. Small mammals such as rodents and shrews are implicated as major natural reservoirs for these microbial agents. Nevertheless, in several tropical countries, like India, the diversity of Bartonella in small mammals remain unexplored and limited information exists on the natural transmission cycles (reservoirs and vectors) of these bacteria. Using a multi-locus sequencing approach, we investigated the prevalence, haplotype diversity, and phylogenetic affinities of Bartonella in small mammals and their associated mites in a mixed-use landscape in the biodiverse Western Ghats in southern India. We sampled 141 individual small mammals belonging to eight species. Bartonella was detected in five of the eight species, including three previously unknown hosts. We observed high interspecies variability of Bartonella prevalence in the host community. However, the overall prevalence (52.5%) and haplotype diversity (0.9) was high for the individuals tested. Of the seven lineages of Bartonella identified in our samples, five lineages were phylogenetically related to putative zoonotic species–B. tribocorum, B. queenslandensis, and B. elizabethae. Haplotypes identified from mites were identical to those identified from their host species. This indicates that these Bartonella species may be zoonotic, but further work is necessary to confirm whether these are pathogenic and pose a threat to humans. Taken together, these results emphasize the presence of hitherto unexplored diversity of Bartonella in wild and synanthropic small mammals in mixed-use landscapes. The study also highlights the necessity to assess the risk of spillover to humans and other incidental hosts.

Zoonotic bacterial infections cause both economic and health burdens to humans, especially in developing countries. Bartonella is a diverse group with several species that are infectious to humans. There is limited knowledge of Bartonella diversity and subsequent risk for spillover in several tropical countries, including India. This study, set in a biodiversity hotspot with high human density, reveals a high prevalence and diversity of Bartonella in the most common, and synanthropic small mammals. Several lineages identified are phylogenetically related to zoonotic species known to cause infections in humans. We suggest that there is unexplored diversity of Bartonella in small mammals that reside in human-modified landscapes in India, demonstrating an urgent need for further investigation. By identifying the natural reservoirs of pathogens, their ecology, and their relationship and proximity to humans, we will be able to proactively survey for these under-detected bacterial infections and minimize the burden.

Bartonella species and haplotypes in rodents and their fleas in Lanzarote and El Hierro in the Canary Islands, Spain

Because isolated ecosystems contribute to species variability, especially oceanic island ecosystems, the present work focused on the study of the Bartonella species and haplotypes in Lanzarote and El Hierro, two Canary islands with evident bioclimatic differences between them. A total of 123 rodents and 110 fleas from two islands were screened for the presence of Bartonella by PCR analysis of the gltA and nuoG genes. The overall prevalence was 5.7% in rodents and 20.4% in fleas. A total of seven gltA-haplotypes was found in both rodents and fleas, belonging to the species Bartonella mastomydis and Bartonella tribocorum in Lanzarote, and to Bartonella rochalimae and Bartonella elizabethae in El Hierro, as well as recently described species Bartonella kosoyi in both islands. Besides, potential co-infections were detected based on the nuoG analysis. Further, Xenopsylla cheopis was the only flea species identified. Our study shows that isolated ecosystems such as the Canary Islands lead to the appearance of new Bartonella haplotypes along different biotopes, with diverse flea species involved in the spreading of the pathogen being of great relevance due to the zoonotic potential of the species found.

Bartonella washoensis infection in red squirrels (Sciurus vulgaris) and their ectoparasites in Lithuania

This is the first study to investigate the presence of Bartonella infections in different internal organs of red squirrels and their ectoparasites in Lithuania. A total of 39 roadkill red squirrels were collected. Squirrels were infested with Ixodes ricinus ticks (191) and Ceratophyllus sciurorum fleas (36). The presence of Bartonella spp. was screened using 16 S-23 S rRNA internal transcribed spacer region and bacteria were detected in 38.5 % (15/39) samples of squirrels, 1.0 % (2/191) samples of ticks and 55.5 % (20/36) samples of fleas. The infection rate of different internal organs of squirrels varied from 11.1%-47.4%. The 16 S-23 S rRNA ITS region sequences showed that Bartonella washoensis were detected in squirrels and their ectoparasites. The results from this study support the hypothesis that S. vulgaris and their fleas, C.sciurorum, serve as a major reservoir and a vector, respectively, of zoonotic B. washoensis in Lithuania.

Prevalence and diversity of Bartonella species in small rodents from coastal and continental areas

Worldwide, Bartonella infections are known to inflict a wide range of mammals and, within rodents alone, more than 20 Bartonella species have been detected. There is, however, a lack of studies on the presence of Bartonella spp. in rodents in the Baltic region. We analysed 580 individuals belonging to eight small rodent species trapped in coastal and continental areas of Lithuania during 2015-2016. The presence of Bartonella DNA was examined by real-time PCR targeting the ssrA gene. The molecular characterization of the bacteria strains was based on sequence analysis of two housekeeping genes (rpoB, groEL) and the intergenic spacer region (ITS). For the rodents overall, the prevalence of Bartonella spp. was 54.8%, while the prevalence figures for each of the individual species were 8.3% in M. musculus, 15.8% in A. agrarius, 33.3% in M. arvalis, 42.4% in M. glareolus, 53.4% in M. oeconomus, 57.5% in M. minutus, 79.6% in A. flavicollis to 80% in M. agrestis. Sequence analysis revealed that the Bartonella strains belonged to the B. grahamii, B. taylorii, B. rochalimae, B. tribocorum, B. coopersplainsensis and B. doshiae genogroups. The highest Bartonella infection rates and the highest species diversity were both detected in rodents captured in the coastal area. To our knowledge, these are the first reports of the presence of B. coopersplainsensis, B. doshiae and B. tribocorum in Lithuania.

Fleas of black rats (Rattus rattus) as reservoir host of Bartonella spp. in Chile

Background

Rattus rattus is a widely distributed, invasive species that presents an important role in disease transmission, either directly or through vector arthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities.

Methods

In all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis.

Results

Overall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydis and B. tribocorum. The phylogenetic analysis showed a close relationship with B. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk.

Biocontrol of rats in an urban environment in Southeast Asia using Sarcocystis singaporensis

BACKGROUND

Upon request of the local administration a control campaign targeting commensal rats (Rattus rattus, R. exulans) was conducted in 30 sub-districts (villages) of the World Heritage town Luang Prabang, Northern Laos, using rat bait containing lethal quantities of the parasitic protist Sarcocystis singaporensis. The associated investigations assessed the short-term control efficacy, willingness of residents to co-operate (community approach), and temporal and spatial changes of the urban rat population in response to treatment.

RESULTS

Biological rodent control significantly reduced rodent activity (percentage of positive tracking patches) in the town, from a mean of 25.3% (±12.8% SD) before (January-February) down to 8.0% (±4.4%) after (June) treatment. Reduction of rodent activity relative to three untreated villages was 83%. Similarly, residents observed significantly fewer rats on their properties after the campaign (mean percentage of households (HHs) per village with sightings), whereby reduction of sightings amounted to 57%. There was significant correlation between residents' observation rates and rodent activity. Among 94 rats trapped before and after treatment each, proportions of adult R. exulans and juvenile R. rattus were higher after rodent control, suggesting that a considerable part of the adult house rat population had been removed. Furthermore, a 5% post-campaign incidence of infection suggested that few rats had survived bait uptake.

CONCLUSION

S. singaporensis may be used successfully as tactical biocontrol agent for culling of rats in urban environments. We propose additional components of a long-term rodent management strategy for the town, without which the impact of culling campaigns would be limited. © 2019 Society of Chemical Industry.

Molecular assessment of Bartonella in Gerbillus nanus from Saudi Arabia reveals high levels of prevalence, diversity and co-infection

Bartonellae bacteria are associated with several re-emerging human diseases. These vector-borne pathogens have a global distribution, yet data on Bartonella prevalence and diversity in the Arabian Peninsula are limited. In this study we assessed the Bartonella infection status of the Baluchistan gerbil (Gerbillus nanus), a species associated with pastoral communities throughout the Middle East region, using a multi-gene PCR screening approach. The results demonstrated that 94 (68.1%) of the 138 gerbils trapped on a monthly basis, over a period of one year, were PCR-positive. Sequencing of the gltA gene region confirmed the presence of four discrete Bartonella lineages (I-IV) and high levels of co-infection (33.0%). Each of the four lineages, varied in overall abundance (7.5%-47.9%) and had discernible seasonal peaks. Bartonella status was significantly correlated with ectoparasite presence, but not with sex, nor with season. Statistical analyses further revealed that co-infected individuals had a significantly higher relative body condition. Multi-locus sequence analysis (MLSA) performed with a concatenated dataset of three genetic loci (gltA, nuoG, and rpoB), 1452 nucleotides (nt) in length confirmed that lineage IV, which occurred in 24 PCR-positive animals (25.5%), is most closely related to zoonotic B. elizabethae. The remaining three lineages (I-III) formed a monophyletic clade which, on the basis of gltA was shown to contain bartonellae from diverse Gerbillinae species from the Middle East, suggestive of a gerbil-associated species complex in this region. Lineage I was identical to a Candidatus B. sanaae strain identified previously in Bushy-tailed jirds (Sekeetamys calurus) from Egypt, wherease MLSA indicate that lineages II and III are novel. The high levels of infection and co-infection, together with the presence of multiple Bartonella lineages indicate that Gerbillus nanus is likely a natural reservoir of Bartonella in the Arabian Peninsula.

Detection and genetic characterization of diverse Bartonella genotypes in the small mammals of Singapore

Bartonella species are arthropod-borne bacterial pathogens that infect numerous mammalian species. Small mammals play an important role as natural reservoirs of many Bartonella species, maintaining the greatest diversity of Bartonella described to date. Although Bartonella research has been conducted in Southeast Asia, no studies have been undertaken on small mammals in Singapore. Here, we report the detection and description of Bartonella in small mammals in Singapore during the period of November 2011 to May 2014. BartonellaDNA was detected in 20.8% (22/106) of small mammal spleens with a PCR amplifying the beta subunit of bacterial RNA polymerase (rpoB) gene. Commensal species Rattus norvegicus and Rattus tanezumi had the highest prevalence, 75% (3/4) and 34,5% (10/29), followed by Suncus murinus 30% (6/20), Tupaia glis 16,7% (1/6) and Mus castaneus 13.3% (2/15). Phylogenetic analysis of 18 rpoB gene sequences revealed five Bartonella genotypes circulating in the small mammals of Singapore. Bayesian tip-significance testing demonstrated strong structuring in the geographical signal, indicating that distribution of Bartonella species is correlated to the distribution of their hosts. Major deforestation and fragmentation in Singapore favour synanthropic species that traverse habitats and increase the possibility of spillover to incidental hosts.

Diversity and prevalence of Bartonella species in small mammals from Slovakia, Central Europe

Wild-living rodents are important hosts for zoonotic pathogens. Bartonella infections are widespread in rodents; however, in Slovakia, knowledge on the prevalence of these bacteria in small mammals is limited. We investigated the prevalence and diversity of Bartonella species in the spleens of 640 rodents of six species (Apodemus flavicollis, Apodemus sylvaticus, Myodes glareolus, Microtus arvalis, Microtus subterraneus, and Micromys minutus) and in the European mole (Talpa europaea) from three different habitat types in south-western and central Slovakia. Overall, the prevalence of Bartonella spp. in rodents was 64.8%; a rate of 73.8% was found in natural habitat (deciduous forest), 56.0% in suburban forest park and 64.9% in rural habitat. Bartonella spp. were detected in 63.0% of A. flavicollis, 69% of My. glareolus and 61.1% of M. arvalis and in T. europaea. However, Bartonella were not found in the other examined rodents. Molecular analyses of the 16S-23S rRNA intergenic spacer region revealed the presence of four different Bartonella spp. clusters. We identified B. taylorii, B. rochalimae, B. elizabethae, B. grahamii and Bartonella sp. wbs11 in A. flavicollis and My. glareolus. Bartonella genotypes ascribed to B. taylorii and B. rochalimae were found in M. arvalis. B. taylorii was identified in T. europaea. Questing Ixodes ricinus ticks that were collected at the study sites were not infected with Bartonella. This study improves our understanding of the ecoepidemiology of Bartonella spp. in Europe and underlines the necessity for further research on Bartonella-host-vector associations and their consequences on animal and human health in Slovakia.

First molecular detection and characterization of zoonotic Bartonella species in fleas infesting domestic animals in Tunisia

Background

Bartonellosis is an emerging vector-borne disease caused by different intracellular bacteria of the genus Bartonella (Rhizobiales: Bartonellaceae) that is transmitted primarily by blood-sucking arthropods such as sandflies, ticks and fleas. In Tunisia, there are no data available identifying the vectors of Bartonella spp. In our research, we used molecular methods to detect and characterize Bartonella species circulating in fleas collected from domestic animals in several of the country’s bioclimatic areas.

Results

A total of 2178 fleas were collected from 5 cats, 27 dogs, 34 sheep, and 41 goats at 22 sites located in Tunisia’s five bioclimatic zones. The fleas were identified as: 1803 Ctenocephalides felis (83%) (Siphonaptera: Pulicidae), 266 C. canis (12%) and 109 Pulex irritans (5%) (Siphonaptera: Pulicidae). Using conventional PCR, we screened the fleas for the presence of Bartonella spp., targeting the citrate synthase gene (gltA). Bartonella DNA was detected in 14% (121/866) of the tested flea pools [estimated infection rate (EIR) per 2 specimens: 0.072, 95% confidence interval (CI): 0.060–0.086]. The Bartonella infection rate per pool was broken down as follows: 55% (65/118; EIR per 2 specimens: 0.329, 95% CI: 0.262–0.402) in C. canis; 23.5% (8/34; EIR per 2 specimens: 0.125, 95% CI: 0.055–0.233) in P. irritans and 6.7% (48/714; EIR per 2 specimens: 0.032, 95% CI: 0.025–0.045) in C. felis. Infection rates, which varied significantly by bioclimatic zone (P < 0.0001), were highest in the humid areas. By sequencing, targeting the gltA gene and the 16S–23S rRNA Intergenic Spacer Regions (ITS), we identified three Bartonella zoonotic species: B. elizabethae, B. henselae, B. clarridgeiae, as well as uncharacterized Bartonella genotypes.

Conclusions

To the best of our knowledge, this is the first time that fleas in Tunisia have been shown to carry zoonotic species of Bartonella. The dog flea, Ctenocephalides canis, should be considered the main potential vector of Bartonella. Our study not only provides new information about this vector, but also offers a public health update: medical practitioners and farmers in Tunisia should be apprised of the presence of Bartonella in fleas and implement preventive measures.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2372-5) contains supplementary material, which is available to authorized users.

Bartonella infection in small mammals and their ectoparasites in Lithuania

The Bartonella pathogen is an emerging zoonotic agent. Epidemiological studies worldwide have demonstrated that small mammals are reservoir hosts of Bartonella spp. and their ectoparasites are potential vectors. The aim of this study was to investigate the prevalence of Bartonella infections in small mammals (Rodentia, Insectivora) and their ectoparasites (fleas and ticks) in Lithuania. A total of 430 small mammals representing nine species were captured with live-traps in Lithuania during 2013-2014. A total of 151 fleas representing eight species were collected from 109 (25.8%) small mammals. Five hundred and seventy ticks (Ixodes ricinus) were collected from 68 (16.1%) small mammals. Bartonella DNA was detected in 102 (23.7%) small mammals, 44 (29.1%) fleas and five (3.7%) pooled tick samples. Sequence analysis of 16S-23S rRNA ITS region showed that sequences were identical or similar to Bartonella grahamii, Bartonella taylorii and Bartonella rochalimae. This study is the first investigating the distribution and diversity of Bartonella species in small mammals and their ectoparasites in Lithuania. B. grahamii, B. taylorii, and B. rochalimae were detected in small mammals and their fleas, and B. grahamii in ticks obtained from small mammals.

Progress on research on rodents and rodent-borne zoonoses in South-east Asia

This review aims to synthesise knowledge regarding the taxonomy of South-east Asian murine rodents and the challenges associated with the identification of habitat preferences and associated rodent-borne diseases. Recent studies concerning the Rattini tribe have identified unclear species boundaries that would benefit from further investigation. The development of barcoding may allow more accurate identification of rodents, specifically for complex species. However, knowledge on the distribution and habitat specialisations of many common murine rodents is still scarce, particularly regarding the specific habitat preferences of most synanthropic rodent species (Rattus tanezumi or Rattus exulans). Several studies have analysed the prevalence of major rodent-borne diseases in South-east Asia and it appears that the greatest risk of rodent zoonoses are in the lowland rain-fed and irrigated landscapes, generally in and around rice fields.