Molecular detection, risk factors, and phylogenetic analysis of tick-borne pathogens in dogs from northern Vietnam.

In tropical regions, numerous tick-borne pathogens (TBPs) play a crucial role as causative agents of infectious diseases in humans and animals. Recently, the population of companion and pet dogs has significantly increased in Vietnam; however, information on the occurrence of TBPs is still limited. The objectives of this investigation were to determine the occurrence rate, risk factors, and phylogenetic characteristics of TBPs in dogs from northern Vietnam. Of 341 blood samples tested by PCR, the total infection of TBPs was 73.9% (252/341). Babesia vogeli (18SrRNA gene - 30.5%) was detected most frequently in studied dogs followed by Rickettsia spp. (OmpA gene - 27%), Anaplasma platys (groEL gene - 22%), Bartonella spp. (16SrRNA - 18.8%), Mycoplasma haemocanis (16SrRNA - 9.4%) and Hepatozoon canis (18SrRNA gene - 1.2%), respectively. All samples were negative for Ehrlichia canis and Anaplasma phagocytophylum. Co-infection was detected in 31.4% of the samples (107/341) of which, A. platys/Bartonella spp. (34/94,10%), Rickettsia spp./B. vogeli (19/94, 5.6%), and M. haemocanis/B. vogeli (19/94, 5.6%) were recorded as the three most frequent two species of co-infection types. Statistical analysis revealed a significant correlation between TBP infection and several host variables regarding age, breed, and living area in the current study. The recent findings reported herein, for the first time in Vietnam, are essential for local veterinarians when considering the appropriate approaches for diagnosing these diseases. Furthermore, this data can be used to establish control measures for future surveillance and prevention strategies against canine TBPs in Vietnam.

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

BACKGROUND: Rodents are recognized as the hosts of many vector-borne bacteria and protozoan parasites and play an important role in their transmission and maintenance. Intensive studies have focused on their infections in vectors, especially in ticks, however, vector-borne bacterial and protozoan infections in rodents are poorly understood although human cases presenting with fever may due to their infection have been found. METHODS: From May to October 2019, 192 wild rodents were trapped in wild environment of Guangxi Province, and the spleen samples were collected to reveal the presence of vector-borne bacterial and protozoan infections in them. The microorganisms in rodents were identified by detecting their DNA using (semi-)nested PCR. All the PCR products of the expected size were subjected to sequencing, and then analyzed by BLASTn. Furthermore, all the recovered sequences were subjected to nucleotide identity and phylogenetic analyses. RESULTS: As a result, 192 rodents representing seven species were captured, and Bandicota indica were the dominant species, followed by Rattus andamanensis. Based on the (semi-)nested PCR, our results suggested that Anaplasma bovis, Anaplasma capra, Anaplasma ovis, Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis", "Candidatus E. hainanensis", "Candidatus E. zunyiensis", three uncultured Ehrlichia spp., Bartonella coopersplainsensis, Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella silvatica, two uncultured Bartonella spp., Babesia microti and diverse Hepatozoon were identified in six rodent species. More importantly, six species (including two Anaplasma, two Bartonella, "Ca. N. mikurensis" and Bab. microti) are zoonotic pathogens except Anaplasma bovis and Anaplasma ovis with zoonotic potential. Furthermore, dual infection was observed between different microorganisms, and the most common type of co-infection is between "Ca. N. mikurensis" and other microorganisms. Additionally, potential novel Bartonella species and Hepatozoon species demonstrated the presence of more diverse rodent-associated Bartonella and Hepatozoon. CONCLUSIONS: The results in this work indicated great genetic diversity of vector-borne infections in wild rodents, and highlighted the potential risk of human pathogens transmitted from rodents to humans through vectors.

Molecular evidence of Bartonella spp. in tropical wild birds from the Brazilian Pantanal, the largest wetland in South America.

Despite the worldwide occurrence of bartonellae in a broad range of mammal species, in which they usually cause a long-lasting erythrocytic bacteremia, few studies reported Bartonella spp. in avian hosts. The present work aimed to investigate the occurrence and molecular identity of Bartonella spp. infecting birds in the Pantanal wetland, central-western Brazil using a multigene approach. For this purpose, blood samples were collected from 517 individuals from 13 avian orders in the states of Mato Grosso and Mato Groso do Sul. DNA was extracted from avian blood and 500/517 (96.7%) samples were positive in a conventional PCR targeting the avian ß-actin gene. Nineteen (3.8%) out of 500 avian blood samples were positive in a qPCR assay for Bartonella spp. based on the nuoG gene. Among 19 avian blood DNA samples positive in the qPCR for Bartonella spp., 12 were also positive in the qPCR for Bartonella based on the 16S-23S RNA Intergenic region (ITS). In the PCR assays performed for molecular characterization, one 16S rRNA, three ribC, and one nuoG sequences were obtained. Based on BLASTn results, while 1 nuoG, 2 ribC, and 2 ITS sequences showed high identity to Bartonella henselae, one 16S rRNA and 2 ITS showed high similarity to Bartonella machadoae in the sampled birds. Bartonella spp. related to B. henselae and B. machadoae were detected, for the first time, in wild birds from the Brazilian Pantanal.

A novel clade of bat-associated Bartonella detected in the bat fly Leptocyclopodia ferrari (Diptera: Nycteribiidae) parasitizing Cynopterus brachyotis (Chiroptera: Pteropodidae).

Bartonelloses are emerging infectious diseases that are common in humans and animals worldwide. Several Bartonella species associated with companion animals such as Bartonella henselae and Bartonella rochalimae are species with zoonotic implications and have become a global concern. Other Bartonella species associated with wild animals, however, remain underappreciated particularly in the developing regions of the world. To explore further on this neglected bacterial agent, Leptocyclopodia ferrari (Nycteribiidae) bat flies collected from Cynopterus brachyotis (Pteropodidae), an endemic fruit bat species in Southeast Asia, were molecularly examined for the presence of Bartonella. Both 16 S-23 S ribosomal RNA intergenic spacer region and citrate synthase gene sequences exhibited less than 95 % similarity to all previously reported Bartonella spp. Further phylogenetic analysis revealed a novel clade of this Bartonella sp. with high bootstrap support. The vectorial capacity of bat flies in transmitting this novel pathogen merits further investigation.

Bartonella spp. seroprevalence in tick-exposed Swedish patients with persistent symptoms.

BACKGROUND: Bartonella spp. are emerging pathogens transmitted by arthropod vectors, possibly including ticks. We have investigated signs of bartonellosis in Swedish patients with presumed tick-bite exposure and symptom duration of at least 6 months. METHODS: Serological testing for Bartonella henselae and Bartonella quintana was performed in 224 patients. Symptoms, tick exposure, evidence of co-infection and previous treatments were evaluated. Seropositive patients were compared to a matched group (twofold larger and negative serology) from the same study cohort. RESULTS: Seroprevalence was 7% for B. henselae and 1% for B. quintana, with one patient testing positive to both agents. Tick bites were reported by 63% of the patients in the seropositive group and 88% in the seronegative group and presumed tick exposure was more common in the seronegative group. Animal contact was equally common in both groups, along with reported symptoms. The most common symptoms were fatigue, muscular symptoms, arthralgia and cognitive symptoms. Exposure to co-infections was evenly distributed in the seropositive and seronegative groups. CONCLUSIONS: Antibodies to Bartonella were more common in this cohort of patients than in cohorts of healthy Swedish blood donors in previous studies but lower than those in blood donors from southern Europe. Positive Bartonella serology was not linked to any specific symptom, nor to (suspected) tick-bite exposure.

Adaptation of gltA and ssrA assays for diversity profiling by Illumina sequencing to identify Bartonella henselae, B. clarridgeiae and B. koehlerae.

Introduction. Bartonellosis is an emerging zoonotic disease caused by bacteria of the genus Bartonella. Mixed Bartonella infections are a well-documented phenomenon in mammals and their ectoparasites. The accurate identification of Bartonella species in single and mixed infections is valuable, as different Bartonella species have varying impacts on infected hosts.Gap Statement. Current diagnostic methods are inadequate at identifying the Bartonella species present in mixed infections.Aim. The aim of this study was to adopt a Next Generation Sequencing (NGS) approach using Illumina sequencing technology to identify Bartonella species and demonstrate that this approach can resolve mixed Bartonella infections.Methodology. We used Illumina PCR amplicon NGS to target the ssrA and gltA genes of Bartonella in fleas collected from cats, dogs and a hedgehog in Israel. We included artificially mixed Bartonella samples to demonstrate the ability for NGS to resolve mixed infections and we compared NGS to traditional Sanger sequencing.Results. In total, we identified 74 Ctenocephalides felis, two Ctenocephalides canis, two Pulex irritans and three Archaeopsylla e. erinacei fleas. Real-time PCR of a subset of 48 fleas revealed that twelve were positive for Bartonella, all of which were cat fleas. Sanger sequencing of the ssrA and gltA genes confirmed the presence of Bartonella henselae, Bartonella clarridgeiae and Bartonella koehlerae. Illumina NGS of ssrA and gltA amplicons further confirmed the Bartonella species identity in all 12 flea samples and unambiguously resolved the artificially mixed Bartonella samples.Conclusion. The adaptation and multiplexing of existing PCR assays for diversity profiling via NGS is a feasible approach that is superior to traditional Sanger sequencing for Bartonella speciation and resolving mixed Bartonella infections. The adaptation of other PCR primers for Illumina NGS will be useful in future studies where mixed bacterial infections may be present.

Zoonotic Bartonella species in Eurasian wolves and other free-ranging wild mammals from Italy.

Bartonellae are emerging vector-borne pathogens infecting humans, domestic mammals and wildlife. Ninety-seven red foxes (Vulpes vulpes), 8 European badgers (Meles meles), 6 Eurasian wolves (Canis lupus), 6 European hedgehogs (Erinaceus europaeus), 3 beech martens (Martes foina) and 2 roe deer (Capreolus capreolus) from Italian Nature Conservatory Parks were investigated for Bartonella infection. Several Bartonella species (9.84%; 95% CI: 4.55-15.12), including zoonotic ones, were molecularly detected among wolves (83.3%; 95% CI: 51-100.00), foxes (4.12%; 95% CI: 0.17-8.08), hedgehogs (33.33%; 95% CI: 0.00-71.05) and a roe deer. Bartonella rochalimae was the most common Bartonella species (i.e. in 4 foxes and 2 wolves) detected. Candidatus B. merieuxii and B. vinsonii subsp. berkhoffii were identified for the first time in wolves. Furthermore, Bartonella schoenbuchensis was identified in a roe deer and a new clone with phylogenetic proximity to B. clarridgeiae was detected in European hedgehogs. Zoonotic and other Bartonella species were significantly more frequent in Eurasian wolves (p < .0001), than in other free-ranging wild mammals, representing a potential reservoir for infection in humans and domestic animals.

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.

Flea-borne pathogens in the cat flea Ctenocephalides felis and their association with mtDNA diversity of the flea host.

Flea-borne pathogens were screened from 100 individual cat fleas using a PCR approach, of which 38 % were infected with at least one bacterium. Overall, 28 % of the flea samples were positive for Bartonella as inferred from ITS DNA region. Of these, 25 % (7/28) were identified as Bartonella clarridgeiae, 42.9 % (12/28) as Bartonella henselae consisted of two different strains, and 32.1 % (9/28) as Bartonella koehlerae, which was detected for the first time in Malaysia. Sequencing of gltA amplicons detected Rickettsia DNA in 14 % of cat flea samples, all of them identified as Rickettsia asembonensis (100 %). None of the flea samples were positive for Mycoplasma DNA in 16S rRNA gene detection. Four fleas were co-infected with Bartonella and Rickettsia DNAs. Statistical analyses reveal no significant association between bacterial infection and mtDNA diversity of the cat flea. Nevertheless, in all types of pathogen infections, infected populations demonstrated lower nucleotide and haplotype diversities compared to uninfected populations. Moreover, lower haplotype numbers were observed in infected populations.

Bats are key hosts in the radiation of mammal-associated Bartonella bacteria.

Bats are notorious reservoirs of several zoonotic diseases and may be uniquely tolerant of infection among mammals. Broad sampling has revealed the importance of bats in the diversification and spread of viruses and eukaryotes to other animal hosts. Vector-borne bacteria of the genus Bartonella are prevalent and diverse in mammals globally and recent surveys have revealed numerous Bartonella lineages in bats. We assembled a sequence database of Bartonella strains, consisting of nine genetic loci from 209 previously characterized Bartonella lineages and 121 new cultured isolates from bats, and used these data to perform a comprehensive phylogenetic analysis of the Bartonella genus. This analysis included estimation of divergence dates using a molecular clock and ancestral reconstruction of host associations and geography. We estimate that Bartonella began infecting mammals 62 million years ago near the Cretaceous-Paleogene boundary. Additionally, the radiation of particular Bartonella clades correlate strongly to the timing of diversification and biogeography of mammalian hosts. Bats were inferred to be the ancestral hosts of all mammal-associated Bartonella and appear to be responsible for the early geographic expansion of the genus. We conclude that bats have had a deep influence on the evolutionary radiation of Bartonella bacteria and their spread to other mammalian orders. These results support a 'bat seeding' hypothesis that could explain similar evolutionary patterns in other mammalian parasite taxa. Application of such phylogenetic tools as we have used to other taxa may reveal the general importance of bats in the ancient diversification of mammalian parasites.

Molecular and Serological Survey of the Cat-Scratch Disease Agent (Bartonella henselae) in Free-Ranging Leopardus geoffroyi and Leopardus wiedii (Carnivora: Felidae) From Pampa Biome, Brazil.

The genus Bartonella comprises emerging bacteria that affect humans and other mammals worldwide. Felids represent an important reservoir for several Bartonella species. Domestic cats are the main reservoir of Bartonella henselae, the agent of cat scratch disease (CSD). It can be transmitted directly by scratches and bites from infected cats and via cat fleas. This study aims to investigate the circulation of Bartonella spp. in free-ranging Neotropical wild felids from Southern Brazil using serological and molecular methods. In this study, 53 live-trapped free-ranging wild felids were sampled, 39 Leopardus geoffroyi and 14 Leopardus wiedii, from five municipalities in the Rio Grande, do Sul state, southern Brazil. All captured animals were clinically healthy. Two blood samples of L. geoffroyi were positive, by PCR, for the presence of B. henselae DNA. Conversely, none of L. wiedii blood samples were positive when tested using PCR. Indirect immunofluorescence assay (IFA) showed that 28% of serum samples of wild felids were reactive (seropositive) for B. henselae by immunofluorescence, with titers ranging from 64 to 256. The results presented here provide the first evidence of a Bartonella-enzootic cycle involving L. geoffroyi and L. wiedii, which may account for the spillover of the emerging zoonotic pathogen B. henselae for the indigenous fauna in Southern Brazil.

Detection and phylogenetic analysis of Bartonella species from bat flies on eastern bent-wing bats (Miniopterus fuliginosus) in Japan.

We examined Bartonella prevalence in 281 bat flies collected from 114 eastern bent-wing bats (Miniopterus fuliginosus) in Japan and phylogenetically analyzed with other bat fly and bat strains. The bat flies were identified as Penicilidia jenynsii (PJ; n = 45), Nycteribia allotopa (NA; n = 157), and novel Nycteribia species (NS; n = 79). Bartonella DNAs were detected in 31.7 % (89/281) of bat flies by PCR targeting the citrate synthase (gltA) gene. The prevalence of Bartonella DNA among the bat flies was 47.1 % (74/157) in NA, 15.2 % (12/79) in NS, and 6.7 % (3/45) in PJ. Bartonella bacteria were also isolated from two NA and one NS. A phylogenetic analysis of the gltA sequences revealed that bat fly-associated strains were classified into three lineages and the same lineages of Bartonella were commonly detected from both Nycteribia bat flies and Miniopterus bats. These results suggest that Nycteribia bat flies are potential vectors for transmitting Bartonella among Miniopterus bats.

Detection of Bartonella sp. and a novel spotted fever group Rickettsia sp. in Neotropical fleas of wild rodents (Cricetidae) from Southern Brazil.

The Neotropical region shows a great diversity of fleas, comprising more than 50 genera. The importance of the study of fleas is linked to their potential role as disease vectors. The aim of this study is to investigate the presence of Rickettsia spp. and Bartonella spp. in Neotropical fleas collected from wild rodents in Southern Brazil. From 350 rodents captured, 30 were parasitized by fleas. A total of 61 fleas belonging to two genera and six different species were collected (Craneopsylla minerva minerva, Polygenis occidentalis occidentalis, Polygenis platensis, Polygenis pradoi, Polygenis rimatus, and Polygenis roberti roberti). In 13 % of fleas of three different species (C. minerva, P. platensis, and P. pradoi) Rickettsia sp. DNA was found. Phylogenetic analysis of concatenated sequences of gltA, htrA, and ompA genes showed that Rickettsia sp. found in rodent fleas (referred as strain Taim) grouped together with Spotted Fever Group Rickettsia. In reference to Bartonella spp., five genotypes were identified in seven fleas of two species (C. minerva and P. platensis) and in five rodent spleens. Also, 207 frozen samples of wild rodents were screened for these pathogens: while none was positive for Rickettsia spp.; five rodent spleens were PCR-positive for Bartonella spp.. Herein, we show the detection of potential novel variants of Bartonella sp. and Rickettsia sp. in fleas collected of wild rodents from Southern Brazil. Further studies are needed to fully characterize these microorganisms, as well as to improve the knowledge on the potential role of Neotropical flea species as diseases vectors.

Molecular investigation of zoonotic intracellular bacteria in Chilean bats.

Intracellular pathogens were investigated for the first time in 55 Chilean bats belonging to six species. Using a conventional PCR protocol targeting a fragment of the ITS region, 21 bats (38 %) were positive for DNA of Bartonella sp. Molecular characterization of fragments of the gltA, rpoB and fstZ genes and subsequent phylogenetic analysis indicated the presence of diverse genotypes related to Bartonella from bats worldwide. DNA from C. burnetii was investigated using a real-time PCR (qPCR) protocol targeting the IS1111 gene and yielded positive results for 5 individuals (9%), being the first report of C. burnetii in wildlife in Chile. All bats were negative for Rickettsia sp., evaluated by qPCR for the gltA gene, confirming that bats do not act as important reservoirs for Rickettsia. This preliminary survey calls for more comprehensive studies on the epidemiology of these agents, including larger sample sizes, the evaluation of potential transmission routes and spillover potential.

Hopping species and borders: detection of Bartonella spp. in avian nest fleas and arctic foxes from Nunavut, Canada.

BACKGROUND: In a warmer and more globally connected Arctic, vector-borne pathogens of zoonotic importance may be increasing in prevalence in native wildlife. Recently, Bartonella henselae, the causative agent of cat scratch fever, was detected in blood collected from arctic foxes (Vulpes lagopus) that were captured and released in the large goose colony at Karrak Lake, Nunavut, Canada. This bacterium is generally associated with cats and cat fleas, which are absent from Arctic ecosystems. Arctic foxes in this region feed extensively on migratory geese, their eggs, and their goslings. Thus, we hypothesized that a nest flea, Ceratophyllus vagabundus vagabundus (Boheman, 1865), may serve as a vector for transmission of Bartonella spp. METHODS: We determined the prevalence of Bartonella spp. in (i) nest fleas collected from 5 arctic fox dens and (ii) 37 surrounding goose nests, (iii) fleas collected from 20 geese harvested during arrival at the nesting grounds and (iv) blood clots from 57 adult live-captured arctic foxes. A subsample of fleas were identified morphologically as C. v. vagabundus. Remaining fleas were pooled for each nest, den, or host. DNA was extracted from flea pools and blood clots and analyzed with conventional and real-time polymerase chain reactions targeting the 16S-23S rRNA intergenic transcribed spacer region. RESULTS: Bartonella henselae was identified in 43% of pooled flea samples from nests and 40% of pooled flea samples from fox dens. Bartonella vinsonii berkhoffii was identified in 30% of pooled flea samples collected from 20 geese. Both B. vinsonii berkhoffii (n = 2) and B. rochalimae (n = 1) were identified in the blood of foxes. CONCLUSIONS: We confirm that B. henselae, B. vinsonii berkhoffii and B. rochalimae circulate in the Karrak Lake ecosystem and that nest fleas contain B. vinsonii and B. henselae DNA, suggesting that this flea may serve as a potential vector for transmission among Arctic wildlife.

Molecular detection of pathogens in ticks and fleas collected from companion dogs and cats in East and Southeast Asia.

BACKGROUND: Ticks and fleas are considered amongst the most important arthropod vectors of medical and veterinary concern due to their ability to transmit pathogens to a range of animal species including dogs, cats and humans. By sharing a common environment with humans, companion animal-associated parasitic arthropods may potentially transmit zoonotic vector-borne pathogens (VBPs). This study aimed to molecularly detect pathogens from ticks and fleas from companion dogs and cats in East and Southeast Asia. METHODS: A total of 392 ticks and 248 fleas were collected from 401 infested animals (i.e. 271 dogs and 130 cats) from China, Taiwan, Indonesia, Malaysia, Singapore, Thailand, the Philippines and Vietnam, and molecularly screened for the presence of pathogens. Ticks were tested for Rickettsia spp., Anaplasma spp., Ehrlichia spp., Babesia spp. and Hepatozoon spp. while fleas were screened for the presence of Rickettsia spp. and Bartonella spp. RESULT: Of the 392 ticks tested, 37 (9.4%) scored positive for at least one pathogen with Hepatozoon canis being the most prevalent (5.4%), followed by Ehrlichia canis (1.8%), Babesia vogeli (1%), Anaplasma platys (0.8%) and Rickettsia spp. (1%) [including Rickettsia sp. (0.5%), Rickettsia asembonensis (0.3%) and Rickettsia felis (0.3%)]. Out of 248 fleas tested, 106 (42.7%) were harboring at least one pathogen with R. felis being the most common (19.4%), followed by Bartonella spp. (16.5%), Rickettsia asembonensis (10.9%) and "Candidatus Rickettsia senegalensis" (0.4%). Furthermore, 35 Rhipicephalus sanguineus ticks were subjected to phylogenetic analysis, of which 34 ticks belonged to the tropical and only one belonged to the temperate lineage (Rh. sanguineus (sensu stricto)). CONCLUSION: Our data reveals the circulation of different VBPs in ticks and fleas of dogs and cats from Asia, including zoonotic agents, which may represent a potential risk to animal and human health.

Multiple locus variable number tandem repeat analysis for the characterization of wild feline Bartonella species and subspecies.

Bartonella genus includes an increasing number of species and subspecies, especially among wild felids, the positioning of which, with regards to the zoonotic species Bartonella henselae, is important to determine. The aim of this study was to test the ability of a molecular typing technique to distinguish between various Bartonella isolates obtained from four different species of free-ranging and captive wild felids and to identify key profiles or markers allowing differentiating them from each other and/or from B. henselae or B. koehlerae. A molecular typing technique for B. henselae based on the polymorphism of variable number tandem repeat units (VNTR) called MLVA (Multiple Locus VNTR Analysis) was applied to 24 Bartonella isolates from free-ranging or captive wild felids, 19 of which were obtained from California and five from three countries in Southern Africa, and compared with 49 B. henselae isolates from cats, dog or humans from the United States including the human ATCC (American Type Culture Collection) reference strain, B. henselae Houston 1. MLVA allowed distinguishing Bartonella isolates from wild felids from either B. henselae or B. koehlerae. We confirmed infection of semi-captive cheetahs with an isolate similar to a Californian bobcat isolate. MLVA also confirmed the unique profile of a free-ranging cheetah isolate from Namibia. Specific profiles were observed making MVLA a useful identification/classification tool of these wild felid isolates and suggesting that they are highly adapted to a specific feline reservoir. Finally, circulation of B. henselae isolates between domestic cats, wild felids and humans is likely occurring, based on the close allelic profiles of some isolates.

The Bartonella autotransporter BafA activates the host VEGF pathway to drive angiogenesis.

Pathogenic bacteria of the genus Bartonella can induce vasoproliferative lesions during infection. The underlying mechanisms are unclear, but involve secretion of an unidentified mitogenic factor. Here, we use functional transposon-mutant screening in Bartonella henselae to identify such factor as a pro-angiogenic autotransporter, called BafA. The passenger domain of BafA induces cell proliferation, tube formation and sprouting of microvessels, and drives angiogenesis in mice. BafA interacts with vascular endothelial growth factor (VEGF) receptor-2 and activates the downstream signaling pathway, suggesting that BafA functions as a VEGF analog. A BafA homolog from a related pathogen, Bartonella quintana, is also functional. Our work unveils the mechanistic basis of vasoproliferative lesions observed in bartonellosis, and we propose BafA as a key pathogenic factor contributing to bacterial spread and host adaptation.

Bartonella species in medically important mosquitoes, Central Europe.

Here, we provide the first mass molecular screening of medically important mosquitoes for Bartonella species using multiple genetic markers. We examined a total of 72,115 mosquito specimens, morphologically attributed to Aedes vexans (61,050 individuals), Culex pipiens (10,484 individuals) and species of the Anopheles maculipennis complex (581 individuals) for Bartonella spp. The initial screening yielded 63 Bartonella-positive A. vexans mosquitoes (mean prevalence 0.1%), 34 Bartonella-positive C. pipiens mosquitoes (mean prevalence 0.3%) and 158 Bartonella-positive A. maculipennis group mosquitoes (mean prevalence 27.2%). Several different Bartonella ITS sequences were recovered. This study highlights the need for molecular screening of mosquitoes, the most important vectors of arthropod-borne pathogens, for potential bacterial agents.

Rats as potential reservoirs for neglected zoonotic Bartonella species in Flanders, Belgium.

BACKGROUND: Bartonella spp. are vector-borne pathogens transmitted to humans via blood-sucking arthropods. Rodents such as the black rat (Rattus rattus) and Norway rat (R. norvegicus) are thought to be the main reservoirs. An infection with rodent-associated Bartonella spp. may cause severe symptoms in humans such as endocarditis and neuroretinitis. The current knowledge of Bartonella prevalence in rats from western Europe is scarce. METHODS: Rats and a few other rodent by-catches were trapped in the context of a rodenticide resistance study at different sites in Flanders, Belgium. During dissection, biometric data were collected, and spleen tissues were taken. DNA was extracted from spleen samples and tested for Bartonella spp. by conventional generic polymerase chain reaction (PCR). To determine the Bartonella species, a selected number of amplicons were sequenced and compared with GenBank entries. RESULTS: In total, 1123 rodents were trapped. The predominate species was R. norvegicus (99.64%). Other rodents trapped included: two water voles (Arvicola amphibius, 0.18%); one colour rat (R. norvegicus forma domestica, 0.09%); and one muskrat (Ondatra zibethicus, 0.09%). PCR analysis of 1097 rodents resulted in 410 (37.37%, 95% CI: 34.50-40.31%) Bartonella spp. DNA-positive samples. Bartonella tribocorum (94.68%, 95% CI: 88.02-98.25%) was the most frequently detected Bartonella species, followed by B. grahamii (3.19%, 95% CI: 0.66-9.04%) and B. doshiae (1.06%, 95% CI: 0.03-5.79%). An uncultured Bartonella species occurred in one water vole (1.06%, 95% CI: 0.03-5.79%). There was a significantly higher Bartonella prevalence in older rats compared to juveniles and a significant difference in Bartonella prevalence concerning the localisation of trapping sites. In contrast, there was no statistically significant difference in Bartonella prevalence regarding sex, degree of urbanisation and season. CONCLUSIONS: Based on the high prevalence found, we conclude that the Norway rat seems to be a key reservoir host for zoonotic B. tribocorum in Belgium.