Identification of novel Bartonella spp. in bats and evidence of Asian gray shrew as a new potential reservoir of Bartonella

Zalati CS, Hamdan RH, Samoh A, Loong SK. Molecular prevalence of Bartonella spp. in bat flies in east coast Malaysia

Bats are a significant reservoir for numerous pathogens, including Bartonella spp. It is one of the emerging zoonotic bacterial diseases that can be transmitted to humans and may cause various unspecific clinical manifestations. Thus, bartonellosis is rarely diagnosed and is regarded as a neglected vector-borne disease (VBD). Bat flies have been hypothesised to be a vector in the transmission of pathogens among bats. They are host-specific, which reduces the likelihood of pathogen transmission across bat species; however, they are likely to maintain high pathogen loads within their host species. To explore the presence of Bartonella spp. in bat flies from Peninsular Malaysia; bat fly samples collected from various sites at the east coast states were subjected to molecular detection for Bartonella spp. It was discovered that 38.7 % of bats from Terengganu and Kelantan were infested with bat flies; however, no bat fly was found in bats collected from Pahang. The collected bat flies belonged to the families Nycteribiidae (79.6 %) and Streblidae (20.4 %). The collected bat flies were pooled according to the locations and species into 39 pools. Out of these 39 pools, 66.7 % (n = 26) were positive for Bartonella spp. by PCR. Sequence analyses of five randomly selected PCR-positive pools revealed that pools from Kelantan (n = 3) have the closest sequence identities (99 %) to Bartonella spp. strain Lisso-Nig-922 from Nigeria. However, the other pools from Terengganu (n = 2) were closely related to Bartonella spp. strain KP277 from Thailand and Bartonella spp. strain Rhin-3 from the Republic of Georgia with 99 % and 100 % sequence identity, respectively. This suggests that the Bartonella spp. found in Malaysian bat flies are genetically diverse and can potentially serve as reservoirs for pathogenic Bartonella spp.

White-Toothed Shrews (Genus Crocidura): Potential Reservoirs for Zoonotic Leptospira spp. and Arthropod-Borne Pathogens?

Three species of white-toothed shrews of the order Eulipotyphla are present in central Europe: the bicolored (Crocidura leucodon), greater (Crocidura russula) and lesser (Crocidura suaveolens) white-toothed shrews. Their precise distribution in Germany is ill-defined and little is known about them as reservoirs for zoonotic pathogens (Leptospira spp., Coxiella burnetii, Brucella spp., Anaplasma phagocytophilum, Babesia spp., Neoehrlichia mikurensis and Bartonella spp.). We investigated 372 Crocidura spp. from Germany (n = 341), Austria (n = 18), Luxembourg (n = 2) and Slovakia (n = 11). West European hedgehogs (Erinaceus europaeus) were added to compare the presence of pathogens in co-occurring insectivores. Crocidura russula were distributed mainly in western and C. suaveolens mainly in north-eastern Germany. Crocidura leucodon occurred in overlapping ranges with the other shrews. Leptospira spp. DNA was detected in 28/227 C. russula and 2/78 C. leucodon samples. Further characterization revealed that Leptospira kirschneri had a sequence type (ST) 100. Neoehrlichia mikurensis DNA was detected in spleen tissue from 2/213 C. russula samples. Hedgehogs carried DNA from L. kirschneri (ST 100), L. interrogans (ST 24), A. phagocytophilum and two Bartonella species. This study improves the knowledge of the current distribution of Crocidura shrews and identifies C. russula as carrier of Leptospira kirschneri. However, shrews seem to play little-to-no role in the circulation of the arthropod-borne pathogens investigated.

Prevalence and Genetic Diversity of Bartonella Spp. in Northern Bats (Eptesicus nilssonii) and Their Blood-Sucking Ectoparasites in Hokkaido, Japan

We investigated the prevalence of Bartonella in 123 northern bats (Eptesicus nilssonii) and their ectoparasites from Hokkaido, Japan. A total of 174 bat fleas (Ischnopsyllus needhami) and two bat bugs (Cimex japonicus) were collected from the bats. Bartonella bacteria were isolated from 32 (26.0%) of 123 bats. Though Bartonella DNA was detected in 79 (45.4%) of the bat fleas, the bacterium was isolated from only one bat flea (0.6%). The gltA sequences of the isolates were categorized into genotypes I, II, and III, which were found in both bats and their fleas. The gltA sequences of genotypes I and II showed 97.6% similarity with Bartonella strains from a Finnish E. nilssonii and a bat flea from a E. serotinus in the Netherlands. The rpoB sequences of the genotypes showed 98.9% similarity with Bartonella strain 44722 from E. serotinus in Republic of Georgia. The gltA and rpoB sequences of genotype III showed 95.9% and 96.7% similarity with Bartonella strains detected in shrews in Kenya and France, respectively. Phylogenetic analysis revealed that Bartonella isolates of genotypes I and II clustered with Bartonella strains from Eptesicus bats in Republic of Georgia and Finland, Myotis bats in Romania and the UK, and a bat flea from an Eptesicus bat in Finland. In contrast, genotype III formed a clade with B. florencae, B. acomydis, and B. birtlesii. These data suggest that northern bats in Japan harbor two Bartonella species and the bat flea serves as a potential vector of Bartonella transmission among the bats.

Molecular Detection and Phylogenetic Analyses of Diverse Bartonella Species in Bat Ectoparasites Collected from Yunnan Province, China

Bartonella species has been validated as blood-borne bacteria in mammals and has a substantial opportunity to be harbored by a variety of hematophagous arthropod vectors. Bats, along with their ectoparasites, are recognized worldwide as one of the natural reservoir hosts for these bacteria. However, there have been few investigations of Bartonella bacteria toward a broad range of obligated bat ectoparasites in China. Here, molecular detection of Bartonella species was performed to survey the infection among bat ectoparasites and follow-up phylogenetic analyses to further characterize the evolutionary relationships of the genus. A total of 434 bat ectoparasites involving four types of arthropods, namely, bat mites, bat tick, bat fleas, and bat flies (further divided into traditionally fly-like bat flies and wingless bat flies) were collected in 10 trapping sites in Yunnan Province, southwestern China. Bartonella was detected by PCR amplification and sequencing through four gene target fragments (gltA, ftsZ, rpoB, and ITS). Accordingly, diverse Bartonella species were discovered, including both the validated species and the novel genotypes, which were characterized into several geographical regions with high prevalence. Phylogenetic analyses based on gltA and multi-locus concatenated sequences both demonstrated strong phylogeny-trait associations of Bartonella species from bats and their parasitic arthropods, suggesting the occurrence of host switches and emphasizing the potential connecting vector role of these ectoparasites. Nevertheless, the maintenance and transmission of Bartonella in both bat and hemoparasite populations have not been fully understood, as well as the risk of spillage to humans, which warrants in-depth experimental studies focusing on these mammals and their ectoparasites.

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.

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.

Bats and their ectoparasites (Nycteribiidae and Spinturnicidae) carry diverse novel Bartonella genotypes, China

Bartonella species are facultative intracellular bacteria and recognized worldwide as emerging zoonotic pathogens. Bartonella were isolated or identified by polymerase chain reaction (PCR) in bats and their ectoparasites worldwide, whereas the association between them was scarce, especially in Asia. In this study, a retrospective analysis with frozen samples was carried out to identify the genetic diversity of Bartonella in bats and their ectoparasites and to investigate the relationships of Bartonella carried by bats and their ectoparasites. Bats and their ectoparasites (bat flies and bat mites) were collected from caves in Hubei Province, Central China, from May 2018 to July 2020. Bartonella were screened by PCR amplification and sequencing of three genes (gltA, rpoB, and ftsZ). Bats, bat flies, and bat mites carried diverse novel Bartonella genotypes with a high prevalence. The sharing of some Bartonella genotypes between bats and bat flies or bat mites indicated a potential role of bat flies and bat mites as vectors of bartonellae, while the higher genetic diversity of Bartonella in bat flies than that in bats might be due to the vertical transmission of this bacterium in bat flies. Therefore, bat flies might also act as reservoirs of Bartonella. In addition, human‐pathogenic B. mayotimonesis was identified in both bats and their ectoparasites, which expanded our knowledge on the geographic distribution of this bacterium and suggested a potential bat origin with bat flies and bat mites playing important roles in the maintenance and transmission of Bartonella.

Assessment of Genetic Diversity and Symbiotic Efficiency of Selected Rhizobia Strains Nodulating Lentil (Lens culinaris Medik.)

A total of 14 Rhizobium strains were isolated from lentil accessions grown at the ICARDA experimental research station at Marchouch in Morocco and used for molecular characterization and symbiotic efficiency assessment. Individual phylogenetic analysis using the 16S rRNA gene, house-keeping genes rpoB, recA, and gyrB, and symbiotic genes nodD and nodA along with Multilocus Sequence Analysis (MLSA) of the concatenated genes (16S rRNA-rpoB-recA-gyrB) was carried out for the identification and clustering of the isolates. The symbiotic efficiency of the strains was assessed on three Moroccan lentil cultivars (Bakria, Chakkouf, and Zaria) based on the number of nodules, plant height, plant dry weight, and total nitrogen content in leaves. The results showed that the individual phylogenetic analysis clustered all the strains into Rhizobium laguerreae and Rhizobium leguminosarum with sequence similarity ranging from 94 to 100%, except one strain which clustered with Mesorhizobium huakuii with sequence similarity of 100%. The MLSA of the concatenated genes and the related percentages of similarity clustered these strains into two groups of Rhizobium species, with one strain as a new genospecies when applying the threshold of 96%. For symbiotic efficiency, the Bakria variety showed the best association with 10 strains compared to its non-inoculated control (p-value ≤ 0.05), followed by Chakkouf and Zaria. The present study concluded that the genetic diversity and the symbiotic efficiency of Rhizobium strains appeared to be mainly under the control of the lentil genotypes.

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.

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.

Genomic Characterization of the Novel Bartonella refiksaydamii sp. Isolated from the Blood of a Crocidura suaveolens (Pallas, 1811)

Bartonella species are reemerging infectious agents that are transmitted by arthropod vectors among animals and/or humans. At least 13 of the 35 currently recognized Bartonella species are pathogenic for humans. Most of the pathogenic species, except Bartonella quintana and Bartonella bacilliformis, are zoonotic agents with animal reservoirs, including cats, dogs, coyotes, foxes, cattle, and rodents. In this study, a novel Bartonella species was isolated from the blood of a Crocidura suaveolens (Pallas, 1811) Lesser shrew that was captured in the Bartın region of Northwestern Turkey. The strain, RSKK 19006, was characterized using whole-genome sequencing and comparison, multilocus sequence typing (gltA, rpoB, ssrA, nuoG, and 16S rRNA) and internal transcribed spacer sequencing, electron microscopy scanning, biochemical tests, and MALDI-TOF MS (matrix assisted laser desorption ionization-time of flight mass spectrometry). This novel Bartonella is a Gram-negative, rod-shaped, microaerophilic bacterium and has neither flagella nor pilus. As a consequence, we propose to name this new species Bartonella refiksaydamii sp. nov. in Bartonella genus. The zoonotic potential of this novel Bartonella species is as yet unknown.

Isolation of Candidatus Bartonella rousetti and Other Bat-associated Bartonellae from Bats and Their Flies in Zambia

Bat-associated bartonellae, including Bartonella mayotimonensis and Candidatus Bartonella rousetti, were recently identified as emerging and potential zoonotic agents, respectively. However, there is no report of bat-associated bartonellae in Zambia. Thus, we aimed to isolate and characterize Bartonella spp. from bats and bat flies captured in Zambia by culturing and PCR. Overall, Bartonella spp. were isolated from six out of 36 bats (16.7%), while Bartonella DNA was detected in nine out of 19 bat flies (47.3%). Subsequent characterization using a sequence of five different genes revealed that three isolates obtained from Egyptian fruit bats (Rousettus aegyptiacus) were Ca. B. rousetti. The isolates obtained from insectivorous bats (Macronycteris vittatus) were divided into two previously unclassified bat-associated bartonellae. A phylogenetic analysis of the six genotypes of Bartonella gltA sequences from nine pathogen-positive bat flies revealed that three genotypes belonged to the same clades as bat-associated bartonellae, including Ca. B. rousetti. The other three genotypes represented arthropod-associated bartonellae, which have previously been isolated only from ectoparasites. We demonstrated that Ca. B. rousetti is maintained between bats (R. aegyptiacus) and bat flies in Zambia. Continuous surveillance of Bartonella spp. in bats and serological surveys in humans in Africa are warranted to evaluate the public health importance of bat-associated bartonellae.

Isolation and genetic properties of Bartonella in eastern bent-wing bats (Miniopterus fuliginosus) in Japan

The prevalence and genetic characteristics of Bartonella species in eastern bent-wing bats (Miniopterus fuliginosus) from Japan were investigated. Bartonella bacteria were isolated from 12/50 (24%) of bats examined. Analyses of sequence similarities of the citrate synthase gene (gltA) and RNA polymerase beta-subunit-encoding (rpoB) gene indicated that the isolates from M. fuliginosus were distinct from those present in known Bartonella species as the levels of similarity for both of the genes were lower than the cut-off values for species identification in Bartonella. A phylogenetic analysis of the gltA sequences revealed that the Miniopterus bat-associated strains fell into five genotypes (I to V). Though genotypes I to IV formed a clade with Bartonella from Miniopterus bats from Taiwan, genotype V made a monophyletic clade separate from other bat isolates. In a phylogenetic analysis with the concatenated sequences of the 16S rRNA, gltA, rpoB, cell division protein (ftsZ) gene, and riboflavin synthase gene (ribC), isolates belonging to genotypes I to IV clustered with Bartonella strains from Taiwanese Miniopterus bats, similar to the outcome of the phylogenetic analysis with gltA, whereas genotype V also made a monophyletic clade separate from other bat-associated Bartonella strains. The present study showed that M. fuliginosus in Japan harbor both genus Miniopterus-specific Bartonella suggesting to be specific to the bats in Japan.

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The prevalence of Bartonella in Miniopterus fuliginosus was 24%(12/50).

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M. fuliginosus in Japan harbored two novel Bartonella species in their blood.

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One Bartonella species was the genus Miniopterus-specific Bartonella.

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The other was distinct from other known bat-associated Bartonella.

Genetic diversity of Bartonella spp. in vampire bats from Brazil

Recently, an increasing number of Bartonella species have been emerged to cause human diseases. Among animal reservoirs for Bartonella spp., bats stand out due to their high mobility, wide distribution, social behaviour and long-life span. Although studies on the role of vampire bats in the epidemiology of rabies have been extensively investigated in Latin America, information on the circulation and genetic diversity of Bartonella species in these bat species is scarce. In the present work, 208 vampire bats, namely Desmodus rotundus (the common vampire bat; n = 167), Diphylla ecaudata (the hairy-legged vampire bat; n = 32) and Diaemus youngii (the white-winged vampire bat; n = 9) from 15 different states in Brazil were sampled. DNA was extracted from liver tissue samples and submitted to real-time PCR (qPCR) and conventional PCR (cPCR) assays for Bartonella spp. targeting five genetic loci, followed by phylogenetic and genotype network analyses. Fifty-one out of 208 liver samples (24.51%) were positive for Bartonella DNA in the ITS real-time PCR assay [40 (78.43%) of them were from D. rotundus from 11 states, and 11 (21.57%) samples from D. ecaudata from three states. Eleven genotypes were found for each gltA and rpoB genes. Several ITS sequences detected in the present study clustered within the lineage that includes B. bacilliformis and B. ancachensis. The Bayesian phylogenetic inference based on the gltA gene positioned the obtained sequences in six different clades, closely related to Bartonella genotypes previously detected in D. rotundus and associated ectoparasites sampled in Latin America. On the other hand, the Bartonella rpoB genotypes clustered together with the ruminant species, B. schoenbuchensis and B. chomelii. The present study describes for the first time the molecular detection of Bartonella spp. in D. ecaudata bats. It also indicates that Bartonella spp. of vampire bats are genetically diverse and geographically widespread in Brazil.

Coxiella and Bartonella spp. in bats (Chiroptera) captured in the Brazilian Atlantic Forest biome

BACKGROUND

The role of bats as reservoirs of zoonotic agents, especially pathogenic bacteria such as Bartonella and Coxiella, has been discussed around the world. Recent studies have identified bats as potential hosts of species from the proteobacteria phylum. In Brazil, however, the role of bats in the natural cycle of these agents is poorly investigated and generally neglected. In order to analyze the participation of bats in the epidemiology of diseases caused by Bartonella, Coxiella, Rickettsia, Anaplasma and Ehrlichia, we conducted a descriptive epidemiological study in three biogeographic regions of the Brazilian Atlantic Forest.

RESULTS

Tissues of 119 bats captured in preserved areas in the states of Rio de Janeiro, Bahia and Santa Catarina from 2014 to 2015 were submitted to molecular analysis using specific primers. Bartonella spp. was detected in 22 spleen samples (18.5%, 95% CI: 11.9-26.6), whose phylogenetic analysis revealed the generation of at least two independent clusters, suggesting that these may be new unique genotypes of Bartonella species. In addition, four samples (3.4%, 95% CI: 0.9-8.3) were positive for the htpAB gene of C. burnetii [spleen (2), liver (1) and heart (1)]. Rickettsia spp., Anaplasma and Ehrlichia were not identified. This is the first study reporting C. burnetii and Bartonella spp. infections in bats from the Atlantic Forest biome.

CONCLUSIONS

These findings shed light on potential host range for these bacteria, which are characterized as important zoonotic pathogens.

Bartonella DNA in heart tissues of bats in central and eastern Europe and a review of phylogenetic relations of bat-associated bartonellae

Background

Bats are among the most widely distributed mammals worldwide and can represent hosts or reservoirs for a number of different pathogens. Bartonella spp. are opportunistic bacterial pathogens, which are transmitted by a large variety of arthropods. The aim of this study was to investigate the presence and host-associations of these Gram-negative bacteria in heart tissues of bats collected in four different countries from eastern and central Europe and to analyze their phylogenetic relationship with other bat-associated bartonellae.

Results

The results of this study show for the first time the presence of Bartonella spp. DNA in heart tissues of bats from central and eastern Europe. The overall prevalence of the infection was 1.38%. Phylogenetic analysis identified four new Bartonella spp. sequences, which were closely related with other Bartonella previously isolated from bats in Europe and North America.

Conclusions

The gltA sequences of Bartonella spp. showed considerable heterogeneity in the phylogenetic analysis resulting in six different clades. Our study demonstrated the presence of Bartonella spp. only in heart tissues of bats from Romania, with two new bat species recorded as hosts (Myotis cf. alcathoe and Pipistrellus pipistrellus).

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3070-7) contains supplementary material, which is available to authorized users.

Molecular detection of Anaplasma phagocytophilum DNA in the lesser horseshoe bat (Rhinolophus hipposideros) guano

Although bats are increasingly recognised as potential reservoir hosts of human zoonotic pathogens, bacteria in bats are still poorly studied. To investigate the DNA faecal prevalence of the bacterium Anaplasma phagocytophilum, we sampled 23 lesser horseshoe bat (Rhinolophus hipposideros) maternity colonies located in buildings (churches, barns) in rural villages of eastern France. A total of 552 faecal samples were collected from 278 individuals. Anaplasma phagocytophilum DNA was detected in the faeces of 63 individuals (22.7%). Such high prevalence might suggest persistent infection in bats and/or a frequent consumption of insect preys carrying bacteria. Faecal DNA prevalence varied highly among colonies but was not related to the colony size. Faecal DNA prevalence was the highest in the Jura Department, where the density of ticks is known to be the highest across the study area. Because the sampled bats live in close proximity to humans, we discuss how concerning the presence of A. phagocytophilum DNA in bat guano is for humans frequenting places of worship that shelter bats. We also advocate future research to understand what a high faecal DNA prevalence in bat guano really implicates in terms of bacteria transmission.

Detection of Bartonella species, including Candidatus Bartonella ovis sp. nov, in ruminants from Mexico and lack of evidence of Bartonella DNA in saliva of common vampire bats (Desmodus rotundus) predating on them

Bartonella spp. have been identified in many bat species worldwide, including the zoonotic species, Candidatus Bartonella mayotimonensis. The common vampire bat (Desmodus rotundus) preys preferentially on livestock in Latin America and is frequently infected with Bartonella spp. To determine the potential role of D. rotundus in transmitting Bartonella to livestock, common vampire bats and bat-bitten domestic ruminants from Mexico were tested for Bartonella infection by blood culture or conventional PCR. Furthermore, to explore the possibility of bite transmission during blood feeding, saliva swabs from 35 D. rotundus known to be either Bartonella bacteremic (N = 17) or blood culture negative (N = 18) were tested by PCR to detect the presence of Bartonella DNA. Twenty (17.1%) of 117 sheep and 16 (34.8%) of 46 cattle were Bartonella bacteremic by PCR testing. However, none of them were infected with Bartonella strains previously isolated from vampire bats and none of the 35 D. rotundus saliva swabs tested were PCR positive for Bartonella. All but two animals among those which were Bartonella culture and/or PCR positive, were infected with either B. bovis (cattle) or B. melophagi (sheep). Two sheep were infected by a possible new species, Candidatus Bartonella ovis, being phylogenetically closer to B. bovis than B. melophagi. This study does not support the role of D. rotundus as a reservoir of Bartonella species infecting livestock, which could be transmitted via bite and blood feeding and therefore suggest limited risk of zoonotic transmission of Bartonella from common vampire bats to humans.

Molecular detection of Bartonella spp. and Rickettsia spp. in bat ectoparasites in Brazil

The family Streblidae comprises a monophyletic group of Hippoboscoidea, hematophagous dipterans that parasitize bats. Bartonella spp. and Rickettsia spp. have been reported in bats sampled in Europe, Africa, Asia, North, Central and South America. However, there are few reports on the Bartonella and Rickettsia bacteria infecting Hippoboscoidea flies and mites. While Spinturnicidae mites are ectoparasites found only in bats, those belonging to the family Macronyssidae comprise mites that also parasitize other mammal species. This study investigates the occurrence and assesses the phylogenetic positioning of Bartonella spp. and Rickettsia spp. found in Streblidae flies and Spinturnicidae and Macronyssidae mites collected from bats captured in Brazil. From May 2011 to April 2012 and September 2013 to December 2014, 400 Streblidae flies, 100 Macronyssidaes, and 100 Spinturnicidae mites were collected from bats captured in two sites in northeastern Nova Iguaçu, Rio de Janeiro, southeastern Brazil. Forty (19.8%) out of 202 Streblidae flies were positive for Bartonella spp. in qPCR assays based on the nuoG gene. Among the flies positive for the bacterium, six (18%) were Paratrichobius longicrus, seven (29%) Strebla guajiro, two (40%) Aspidoptera phyllostomatis, five (11%) Aspidoptera falcata, one (10%) Trichobius anducei, one (25%) Megistopoda aranea, and 18 (32%) Trichobius joblingi, and collected from bats of the following species: Artibeus lituratus, Carollia perspicillata, Artibeus planirostris, Sturnira lilium, and Artibeus obscurus. Six sequences were obtained for Bartonella (nuoG [n = 2], gltA [n = 2], rpoB [n = 1], ribC = 1]). The phylogenetic analysis based on gltA (750pb) gene showed that the Bartonella sequences clustered with Bartonella genotypes detected in bats and ectoparasites previously sampled in Latin America, including Brazil. Only one sample (0.49%) of the species Trichobius joblingi collected from a specimen of Carollia perspicillata was positive for Rickettsia sp. in cPCR based on the gltA gene (401bp). This sequence was clustered with a 'Candidatus Rickettsia andaenae" genotype detected in an Amblyomma parvum tick collected from a rodent in the southern region of Brazilian Pantanal. The sampled Macronyssidae and Spinturnicidae mites were negative for Bartonella spp. and Rickettsia spp. This study demonstrated the first occurrence of Bartonella spp. and Rickettsia spp. DNA in Streblidae flies collected from bats in Brazil.

Bartonella, bats and bugs: A review

Ecological, immunological, and epidemiological factors enable bats to transmit an increasingly recognized spectrum of zoonotic agents, and bartonellae are among those emerging pathogens identified in bats and their arthropod ectoparasites. Current data reveal a multifaceted disease ecology where diverse host species distributed around the world interact with a number of Bartonella spp. and several potential vectors. This review summarizes the methods and findings of studies conducted since 2005 to illustrate that Bartonella bacteremia varies by bat species, location, and other potential variables, such as diet with a very high prevalence in hematophagous bats. Among bat families, Bartonella prevalence ranged from 7.3% among Nycteridae to 54.4% in Miniopteridae. Further research can build on these current data to better determine risk factors associated with Bartonella infection in bat populations and the role of their ectoparasites in transmission.

Diversity and phylogenetic relationships among Bartonella strains from Thai bats

Bartonellae are phylogenetically diverse, intracellular bacteria commonly found in mammals. Previous studies have demonstrated that bats have a high prevalence and diversity of Bartonella infections globally. Isolates (n = 42) were obtained from five bat species in four provinces of Thailand and analyzed using sequences of the citrate synthase gene (gltA). Sequences clustered into seven distinct genogroups; four of these genogroups displayed similarity with Bartonella spp. sequences from other bats in Southeast Asia, Africa, and Eastern Europe. Thirty of the isolates representing these seven genogroups were further characterized by sequencing four additional loci (ftsZ, nuoG, rpoB, and ITS) to clarify their evolutionary relationships with other Bartonella species and to assess patterns of diversity among strains. Among the seven genogroups, there were differences in the number of sequence variants, ranging from 1-5, and the amount of nucleotide divergence, ranging from 0.035-3.9%. Overall, these seven genogroups meet the criteria for distinction as novel Bartonella species, with sequence divergence among genogroups ranging from 6.4-15.8%. Evidence of intra- and intercontinental phylogenetic relationships and instances of homologous recombination among Bartonella genogroups in related bat species were found in Thai bats.

Bartonella Infection in Hematophagous, Insectivorous, and Phytophagous Bat Populations of Central Mexico and the Yucatan Peninsula

Although emerging nonviral pathogens remain relatively understudied in bat populations, there is an increasing focus on identifying bat-associated bartonellae around the world. Many novel Bartonella strains have been described from both bats and their arthropod ectoparasites, including Bartonella mayotimonensis, a zoonotic agent of human endocarditis. This cross-sectional study was designed to describe novel Bartonella strains isolated from bats sampled in Mexico and evaluate factors potentially associated with infection. A total of 238 bats belonging to seven genera were captured in five states of Central Mexico and the Yucatan Peninsula. Animals were screened by bacterial culture from whole blood and/or polymerase chain reaction of DNA extracted from heart tissue or blood. Bartonella spp. were isolated or detected in 54 (22.7%) bats, consisting of 41 (38%) hematophagous, 10 (16.4%) insectivorous, and three (4.3%) phytophagous individuals. This study also identified Balantiopteryx plicata as another possible bat reservoir of Bartonella. Univariate and multivariate logistic regression models suggested that Bartonella infection was positively associated with blood-feeding diet and ectoparasite burden. Phylogenetic analysis identified a number of genetic variants across hematophagous, phytophagous, and insectivorous bats that are unique from described bat-borne Bartonella species. However, these strains were closely related to those bartonellae previously identified in bat species from Latin America.

Evidence and molecular characterization ofBartonellaspp. and hemoplasmas in neotropical bats in Brazil

The order Chiroptera is considered the second largest group of mammals in the world, hosting important zoonotic virus and bacteria.Bartonellaand hemotropic mycoplasmas are bacteria that parasite different mammals’ species, including humans, causing different clinical manifestations. The present work aimed investigating the occurrence and assessing the phylogenetic positioning ofBartonellaspp. andMycoplasmaspp. in neotropical bats sampled from Brazil. Between December 2015 and April 2016, 325 blood and/or tissues samples were collected from 162 bats comprising 19 different species sampled in five states of Brazil. Out of 322 bat samples collected, while 17 (5·28%) were positive to quantitative PCR forBartonellaspp. based onnuoGgene, 45 samples (13·97%) were positive to cPCR assays for hemoplasmas based on 16S rRNA gene. While seven sequences were obtained forBartonella(nuoG) (n= 3),gltA(n= 2),rpoB(n= 1),ftsZ(n= 1), five 16S rRNA sequences were obtained for hemoplasmas. In the phylogenetic analysis, theBartonellasequences clustered withBartonellagenotypes detected in bats sampled in Latin America countries. All five hemoplasmas sequences clustered together as a monophyletic group by Maximum Likelihood and Bayesian Inference analyses. The present work showed the first evidence of circulation ofBartonellaspp. and hemoplasmas among bats in Brazil.

Prevalence, diversity, and host associations of Bartonella strains in bats from Georgia (Caucasus)

Bartonella infections were investigated in seven species of bats from four regions of the Republic of Georgia. Of the 236 bats that were captured, 212 (90%) specimens were tested for Bartonella infection. Colonies identified as Bartonella were isolated from 105 (49.5%) of 212 bats Phylogenetic analysis based on sequence variation of the gltA gene differentiated 22 unique Bartonella genogroups. Genetic distances between these diverse genogroups were at the level of those observed between different Bartonella species described previously. Twenty-one reference strains from 19 representative genogroups were characterized using four additional genetic markers. Host specificity to bat genera or families was reported for several Bartonella genogroups. Some Bartonella genotypes found in bats clustered with those identified in dogs from Thailand and humans from Poland.

Bacteria of the genus Bartonella parasitize erythrocytes and endothelial cells of a wide range of mammals and recently were reported in bats from Africa, Asia, America, and northern Europe. A human disease case in the USA was associated with a novel Bartonella species, which later was identified in bats in Finland. This human case has demonstrated the zoonotic potential of bat-borne Bartonella and underscores the need for extended surveillance and studies of these pathogens. The present work assesses prevalence and diversity of Bartonella in bats in the country of Georgia (southern Caucasus), characterizes reference strains representing diverse genogroups by variation of genetic loci, and evaluates the links between identified Bartonella genogroups and bat hosts. Importantly, some Bartonella genotypes found in bats were close or identical to those identified in dogs and humans. The data indicate that the public health impact of Bartonella carried by bats should be investigated.

Novel Bartonella Species in Insectivorous Bats, Northern China

Bartonella species are emerging human pathogens. Bats are known to carry diverse Bartonella species, some of which are capable of infecting humans. However, as the second largest mammalian group by a number of species, the role of bats as the reservoirs of Bartonella species is not fully explored, in term of their species diversity and worldwide distribution. China, especially Northern China, harbors a number of endemic insectivorous bat species; however, to our knowledge, there are not yet studies about Bartonella in bats in China. The aim of the study was to investigate the prevalence and genetic diversity of Bartonella species in bats in Northern China. Bartonella species were detected by PCR amplification of gltA gene in 25.2% (27/107) bats in Mengyin County, Shandong Province of China, including 1/3 Rhinolophus ferrumequinum, 2/10 Rhinolophus pusillus, 9/16 Myotis fimbriatus, 1/5 Myotis ricketti, 14/58 Myotis pequinius. Phylogenetic analysis showed that Bartonella species detected in bats in this study clustered into ten groups, and some might be novel Bartonella species. An association between Bartonella species and bat species was demonstrated and co-infection with different Bartonella species in a single bat was also observed. Our findings expanded our knowledge on the genetic diversity of Bartonella in bats, and shed light on the ecology of bat-borne Bartonella species.

Phylogenetic and geographic patterns of bartonella host shifts among bat species

The influence of factors contributing to parasite diversity in individual hosts and communities are increasingly studied, but there has been less focus on the dominant processes leading to parasite diversification. Using bartonella infections in bats as a model system, we explored the influence of three processes that can contribute to bartonella diversification and lineage formation: (1) spatial correlation in the invasion and transmission of bartonella among bats (phylogeography); (2) divergent adaptation of bartonellae to bat hosts and arthropod vectors; and (3) evolutionary codivergence between bats and bartonellae. Using a combination of global fit techniques and ancestral state reconstruction, we found that codivergence appears to be the dominant process leading to diversification of bartonella in bats, with lineages of bartonellae corresponding to separate bat suborders, superfamilies, and families. Furthermore, we estimated the rates at which bartonellae shift bat hosts across taxonomic scales (suborders, superfamilies, and families) and found that transition rates decrease with increasing taxonomic distance, providing support for a mechanism that can contribute to the observed evolutionary congruence between bats and their associated bartonellae. While bartonella diversification is associated with host sympatry, the influence of this factor is minor compared to the influence of codivergence and there is a clear indication that some bartonella lineages span multiple regions, particularly between Africa and Southeast Asia. Divergent adaptation of bartonellae to bat hosts and arthropod vectors is apparent and can dilute the overall pattern of codivergence, however its importance in the formation of Bartonella lineages in bats is small relative to codivergence. We argue that exploring all three of these processes yields a more complete understanding of bat-bartonella relationships and the evolution of the genus Bartonella, generally. Application of these methods to other infectious bacteria and viruses could uncover common processes that lead to parasite diversification and the formation of host-parasite relationships.

Evidence of Bartonella spp. in Blood and Ticks (Ornithodoros hasei) of Bats, in French Guiana

We screened blood from 59 bats from French Guiana for Bartonella spp. PCRs were positive for 13.6% and culture was positive in one Noctilio albiventris and one Pteronotus parnellii, as well as in Ornithodoros hasei ticks collected from bats. Two isolated strains represent possible two new species.

The Bacteriome of Bat Flies (Nycteribiidae) from the Malagasy Region: a Community Shaped by Host Ecology, Bacterial Transmission Mode, and Host-Vector Specificity

The Nycteribiidae are obligate blood-sucking Diptera (Hippoboscoidea) flies that parasitize bats. Depending on species, these wingless flies exhibit either high specialism or generalism toward their hosts, which may in turn have important consequences in terms of their associated microbial community structure. Bats have been hypothesized to be reservoirs of numerous infectious agents, some of which have recently emerged in human populations. Thus, bat flies may be important in the epidemiology and transmission of some of these bat-borne infectious diseases, acting either directly as arthropod vectors or indirectly by shaping pathogen communities among bat populations. In addition, bat flies commonly have associations with heritable bacterial endosymbionts that inhabit insect cells and depend on maternal transmission through egg cytoplasm to ensure their transmission. Some of these heritable bacteria are likely obligate mutualists required to support bat fly development, but others are facultative symbionts with unknown effects. Here, we present bacterial community profiles that were obtained from seven bat fly species, representing five genera, parasitizing bats from the Malagasy region. The observed bacterial diversity includes Rickettsia, Wolbachia, and several Arsenophonus-like organisms, as well as other members of the Enterobacteriales and a widespread association of Bartonella bacteria from bat flies of all five genera. Using the well-described host specificity of these flies and data on community structure from selected bacterial taxa with either vertical or horizontal transmission, we show that host/vector specificity and transmission mode are important drivers of bacterial community structure.

Screening of bat faeces for arthropod-borne apicomplexan protozoa: Babesia canis and Besnoitia besnoiti-like sequences from Chiroptera

Background

Bats are among the most eco-epidemiologically important mammals, owing to their presence in human settlements and animal keeping facilities. Roosting of bats in buildings may bring pathogens of veterinary-medical importance into the environment of domestic animals and humans. In this context bats have long been studied as carriers of various pathogen groups. However, despite their close association with arthropods (both in their food and as their ectoparasites), only a few molecular surveys have been published on their role as carriers of vector-borne protozoa. The aim of the present study was to compensate for this scarcity of information.

Findings

Altogether 221 (mostly individual) bat faecal samples were collected in Hungary and the Netherlands. The DNA was extracted, and analysed with PCR and sequencing for the presence of arthropod-borne apicomplexan protozoa. Babesia canis canis (with 99-100 % homology) was identified in five samples, all from Hungary. Because it was excluded with an Ixodidae-specific PCR that the relevant bats consumed ticks, these sequences derive either from insect carriers of Ba. canis, or from the infection of bats. In one bat faecal sample from the Netherlands a sequence having the highest (99 %) homology to Besnoitia besnoiti was amplified.

Conclusions

These findings suggest that some aspects of the epidemiology of canine babesiosis are underestimated or unknown, i.e. the potential role of insect-borne mechanical transmission and/or the susceptibility of bats to Ba. canis. In addition, bats need to be added to future studies in the quest for the final host of Be. besnoiti.

Bartonella species in bats (Chiroptera) and bat flies (Nycteribiidae) from Nigeria, West Africa

Previous and ongoing studies have incriminated bats as reservoirs of several emerging and re-emerging zoonoses. Most of these studies, however, have focused on viral agents and neglected important bacterial pathogens. To date, there has been no report investigating the prevalence of Bartonella spp. in bats and bat flies from Nigeria, despite the fact that bats are used as food and for cultural ritual purposes by some ethnic groups in Nigeria. To elucidate the role of bats as reservoirs of bartonellae, we screened by molecular methods 148 bats and 34 bat flies, Diptera:Hippoboscoidea:Nycteribiidae (Cyclopodia greeffi) from Nigeria for Bartonella spp. Overall, Bartonella spp. DNA was detected in 76 out of 148 (51.4%) bat blood samples tested and 10 out of 24 (41.7%) bat flies tested by qPCR targeting the 16S-23S internal transcribed spacer (ITS) locus. Bartonella was isolated from 23 of 148 (15.5%) bat blood samples, and the isolates were genetically characterized. Prevalence of Bartonella spp. culture-positive samples ranged from 0% to 45.5% among five bat species. Micropterus spp. bats had a significantly higher relative risk of 3.45 for being culture positive compared to Eidolon helvum, Epomophorus spp., Rhinolophus spp., and Chaerephon nigeriae. Bartonella spp. detected in this study fall into three distinct clusters along with other Bartonella spp. isolated from bats and bat flies from Kenya and Ghana, respectively. The isolation of Bartonella spp. in 10.0-45.5% of four out of five bat species screened in this study indicates a widespread infection in bat population in Nigeria. Further investigation is warranted to determine the role of these bacteria as a cause of human and animal diseases in Nigeria.

Bartonella spp. in fruit bats and blood-feeding Ectoparasites in Madagascar

We captured, ectoparasite-combed, and blood-sampled cave-roosting Madagascan fruit bats (Eidolon dupreanum) and tree-roosting Madagascan flying foxes (Pteropus rufus) in four single-species roosts within a sympatric geographic foraging range for these species in central Madagascar. We describe infection with novel Bartonella spp. in sampled Eidolon dupreanum and associated bat flies (Cyclopodia dubia), which nest close to or within major known Bartonella lineages; simultaneously, we report the absence of Bartonella spp. in Thaumapsylla sp. fleas collected from these same bats. This represents the first documented finding of Bartonella infection in these species of bat and bat fly, as well as a new geographic record for Thaumapsylla sp. We further relate the absence of both Bartonella spp. and ectoparasites in sympatrically sampled Pteropus rufus, thus suggestive of a potential role for bat flies in Bartonella spp. transmission. These findings shed light on transmission ecology of bat-borne Bartonella spp., recently demonstrated as a potentially zoonotic pathogen.

Classification of Bartonella strains associated with straw-colored fruit bats (Eidolon helvum) across Africa using a multi-locus sequence typing platform

Bartonellae are facultative intracellular bacteria and are highly adapted to their mammalian host cell niches. Straw-colored fruit bats (Eidolon helvum) are commonly infected with several bartonella strains. To elucidate the genetic diversity of these bartonella strains, we analyzed 79 bartonella isolates from straw-colored fruit bats in seven countries across Africa (Cameroon, Annobon island of Equatorial Guinea, Ghana, Kenya, Nigeria, Tanzania, and Uganda) using a multi-locus sequencing typing (MLST) approach based on nucleotide sequences of eight loci (ftsZ, gltA, nuoG, ribC, rpoB, ssrA, ITS, and 16S rRNA). The analysis of each locus but ribC demonstrated clustering of the isolates into six genogroups (E1 – E5 and Ew), while ribC was absent in the isolates belonging to the genogroup Ew. In general, grouping of all isolates by each locus was mutually supportive; however, nuoG, gltA, and rpoB showed some incongruity with other loci in several strains, suggesting a possibility of recombination events, which were confirmed by network analyses and recombination/mutation rate ratio (r/m) estimations. The MLST scheme revealed 45 unique sequence types (ST1 – 45) among the analyzed bartonella isolates. Phylogenetic analysis of concatenated sequences supported the discrimination of six phylogenetic lineages (E1 – E5 and Ew) corresponding to separate and unique Bartonella species. One of the defined lineages, Ew, consisted of only two STs (ST1 and ST2), and comprised more than one-quarter of the analyzed isolates, while other lineages contained higher numbers of STs with a smaller number of isolates belonging to each lineage. The low number of allelic polymorphisms of isolates belonging to Ew suggests a more recent origin for this species. Our findings suggest that at least six Bartonella species are associated with straw-colored fruit bats, and that distinct STs can be found across the distribution of this bat species, including in populations of bats which are genetically distinct.

Bats, with over 1000 recognized species, represent about 20% of all classified mammalian species worldwide. These mammals have a wide range of ecologies and life-history traits, and are now widely recognized as important reservoirs of many pathogens. Bartonella species have been found distributed in a wide range of mammalian species, including bats. About half of recognized Bartonella species, including one bat-associated species, have been associated with human illness. Previous studies have shown that Bartonella species are extremely diverse, with or without evident specificity to their mammalian hosts. Possessing many unique aspects, bartonellae can serve as a useful biological marker to study how microorganisms have evolved and diversified along with their animal hosts in evolutionary history. In this study, we applied multi-locus sequence typing, or MLST, to study the genetic differences of straw-colored fruit bat (Eidolon helvum)-associated Bartonella species. Our studies suggest Bartonella species have both exchanged genetic materials among species through recombination events and lost genes that are perhaps superfluous to their life cycles, which includes an intracellular stage in mammals.

Bats as reservoir hosts of human bacterial pathogen, Bartonella mayotimonensis

A plethora of pathogenic viruses colonize bats. However, bat bacterial flora and its zoonotic threat remain ill defined. In a study initially conducted as a quantitative metagenomic analysis of the fecal bacterial flora of the Daubenton's bat in Finland, we unexpectedly detected DNA of several hemotrophic and ectoparasite-transmitted bacterial genera, including Bartonella. Bartonella spp. also were either detected or isolated from the peripheral blood of Daubenton's, northern, and whiskered bats and were detected in the ectoparasites of Daubenton's, northern, and Brandt's bats. The blood isolates belong to the Candidatus-status species B. mayotimonensis, a recently identified etiologic agent of endocarditis in humans, and a new Bartonella species (B. naantaliensis sp. nov.). Phylogenetic analysis of bat-colonizing Bartonella spp. throughout the world demonstrates a distinct B. mayotimonensis cluster in the Northern Hemisphere. The findings of this field study highlight bats as potent reservoirs of human bacterial pathogens.

Contrasting patterns in mammal-bacteria coevolution: bartonella and leptospira in bats and rodents

BACKGROUND

Emerging bacterial zoonoses in bats and rodents remain relatively understudied. We conduct the first comparative host-pathogen coevolutionary analyses of bacterial pathogens in these hosts, using Bartonella spp. and Leptospira spp. as a model.

METHODOLOGY/PRINCIPAL FINDINGS

We used published genetic data for 51 Bartonella genotypes from 24 bat species, 129 Bartonella from 38 rodents, and 26 Leptospira from 20 bats. We generated maximum likelihood and Bayesian phylogenies for hosts and bacteria, and tested for coevoutionary congruence using programs ParaFit, PACO, and Jane. Bartonella spp. and their bat hosts had a significant coevolutionary fit (ParaFitGlobal = 1.9703, P≤0.001; m2 global value = 7.3320, P≤0.0001). Bartonella spp. and rodent hosts also indicated strong overall patterns of cospeciation (ParaFitGlobal = 102.4409, P≤0.001; m2 global value = 86.532, P≤0.0001). In contrast, we were unable to reject independence of speciation events in Leptospira and bats (ParaFitGlobal = 0.0042, P = 0.84; m2 global value = 4.6310, P = 0.5629). Separate analyses of New World and Old World data subsets yielded results congruent with analysis from entire datasets. We also conducted event-based cophylogeny analyses to reconstruct likely evolutionary histories for each group of pathogens and hosts. Leptospira and bats had the greatest number of host switches per parasite (0.731), while Bartonella and rodents had the fewest (0.264).

CONCLUSIONS/SIGNIFICANCE

In both bat and rodent hosts, Bartonella exhibits significant coevolution with minimal host switching, while Leptospira in bats lacks evolutionary congruence with its host and has high number of host switches. Reasons underlying these variable coevolutionary patterns in host range are likely due to differences in disease-specific transmission and host ecology. Understanding the coevolutionary patterns and frequency of host-switching events between bacterial pathogens and their hosts will allow better prediction of spillover between mammal reservoirs, and ultimately to humans.

Bats and bacterial pathogens: a review

The occurrence of emerging infectious diseases and their relevance to human health has increased the interest in bats as potential reservoir hosts and vectors of zoonotic pathogens. But while previous and ongoing research activities predominantly focused on viral agents, the prevalence of pathogenic bacteria in bats and their impact on bat mortality have largely neglected. Enteric pathogens found in bats are often considered to originate from the bats' diet and foraging habitats, despite the fact that little is known about the actual ecological context or even transmission cycles involving bats, humans and other animals like pets and livestock. For some bacterial pathogens common in human and animal diseases (e.g. Pasteurella, Salmonella, Escherichia and Yersinia spp.), the pathogenic potential has been confirmed for bats. Other bacterial pathogens (e.g. Bartonella, Borrelia and Leptospira spp.) provide evidence for novel species that seem to be specific for bat hosts but might also be of disease importance in humans and other animals. The purpose of this review is to summarize the current knowledge of bacterial pathogens identified in bats and to consider factors that might influence the exposure and susceptibility of bats to bacterial infection but could also affect bacterial transmission rates between bats, humans and other animals.