O R I G I N A L A R T I C L E
Epidemiology of Bartonella Infection in Rodents and
Shrews in Taiwan
J.-W. Hsieh1, K.-C. Tung2, W.-C. Chen3, J.-W. Lin2, L.-J. Chien4, Y.-M. Hsu5, H.-C. Wang4, B. B. Chomel6and C.-C. Chang1
1Graduate Institute of Veterinary Public Health, National Chung Hsing University, Taichung, Taiwan 2
Department of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan
3Department of Safety Health and Environmental Engineering, Central Taiwan University of Science and Technology, Taichung, Taiwan 4Department of Health, Centers for Disease Control, Taipei, Taiwan
5
Department of Biological Science and Technology, College of Life Sciences, China Medical University, Taichung, Taiwan
6Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA, USA
Impacts
• This is the first study conducted in Taiwan to determine the epidemiology of Bartonella infection in small mammals, and a high prevalence of 41.3% was identified.
• The isolated Bartonella species were diverse and included human patho-genic Bartonella elizabethae and Bartonella grahamii. Our findings also indicated that prevalence of the infection was associated with different ecological environments and animal species.
• Future studies need to be conducted to determine whether these Bartonella species would be responsible for human cases with unknown fever or febrile illness in Taiwan, especially zoonotic B. elizabethae and B. grahamii.
Keywords:
Bartonella species; small mammals; epidemiology; Rattus losea Correspondence:
C.-C. Chang. DVM, MS, PhD, 250 Kuo-Kuang Road, Graduate Institute of Veterinary Public Health, National Chung Hsing University, Taichung 402, Taiwan.
Tel.: +886-4-22840894; Fax: +886-4-22852186;
E-mail: [email protected] Received for publication September 11, 2008 doi: 10.1111/j.1863-2378.2009.01234.x
Summary
During the period of August 2002 and November 2004, an epidemiological investigation for Bartonella infection was conducted in small mammals in Tai-wan. Using whole blood culture on chocolate agar plates, Bartonella species were successfully isolated from 41.3% of the 310 animals tested. The isolation rate of Bartonella species varied among different animal species, including 52.7% of the 169 Rattus norvegicus, 28.6% of the 126 Sucus murinus, 10% of the 10 Rattus rattus and 66.7% of the three Rattus losea. Bacteremia prevalence also varied with the origin of the animals, as 56.2% of the animals captured on farms, 38.6% of the ones captured at harbour sites and 11.8% of the animals captured from urban areas were bacteremic. Through molecular analysis of the gltA gene and 16S/23S intergenic spacer region, genetic diversity of Bartonella organisms was identified, including strains closely related to Bartonella triboco-rum, Bartonella grahamii, Bartonella elizabethae, Bartonella phoceensis and Bartonella rattimassiliensis. Moreover, this is the first report of zoonotic B. eliz-abethae and B. grahamii identified in R. losea, the lesser rice-field rat. Various Bartonella species were identified in R. norvegicus, compared to 97.2% of Suncus murinus with unique Bartonella species. By indirect immunofluores-cence antibody test, using various rodent Bartonella species as antigens, consis-tently low percentage of seropositivity implied that small mammals may play a role as competent reservoirs of Bartonella species in Taiwan. Future studies need to be conducted to determine whether these Bartonella species would be responsible for human cases of unknown fever or febrile illness in Taiwan, especially zoonotic B. elizabethae and B. grahamii.
Introduction
Bartonella infections are mainly vector-borne zoonoses. Although various vertebrate animals have been docu-mented as reservoirs of Bartonella, small mammals have been shown to harbour most of the known Bartonella species. Bartonella talpae was identified in a mole cap-tured near Cambridge in UK in 1905 (Maurin et al., 1997). Bartonella vinsonii subsp. visonii was isolated only once from the blood of a Canadian vole (Microtus penn-sylvanicus) in the 1940s (Baker, 1946). In 1995, three spe-cies isolated from wild rodents were added to the genera Bartonella, including Bartonella grahamii from Clethriono-mys glareolus, Bartonella taylorii from Apodemus sp. and Bartonella doshiae from Microtus arestis (Birtles et al., 1995). In Peru, several Bartonella species were isolated from Phyllotis spp, and Rattus norvegicus was found to carry Bartonella elizabethae (Birtles et al., 1999). In the United States and Portugal, 18% of the rodents was Bartonella bacteremic, and the isolates from R. norvegicus were closely related to B. elizabethae (Ellis et al., 1999). Bartonella tribocorum, Bartonella rattimassiliensis and Bartonella phoceensis have been initially isolated from R. norvegicus rats in France (Heller et al., 1998; Gundi et al., 2004).
Of major importance, several rodent Bartonella species have been shown to be human pathogens. B. elizabethae and B. washoensis were found in patients with endocardi-tis (Daly et al., 1993; Kosoy et al., 2003). Human cases with neuroretinitis or bilateral retinal artery branch occlu-sions were shown to be infected with B. grahamii (Kerk-hoff et al., 1999; Serratrice et al., 2003). In Baltimore, USA, a sero-survey showed that 33% of the inner-city intravenous drug users was seropositive for B. elizabethae (Comer et al., 1996). A cattle rancher with neurological disorders was found to be infected with B. vinsonii subsp. arupensis, possibly from a rodent origin (Welch et al., 1999). These findings clearly demonstrated that small mammals are important reservoirs for various zoonotic Bartonella species.
Prevalence of Bartonella infection varies in small mam-mals in different geographical areas. Previous studies have shown that the prevalence was 17–62% in Europe (Birtles et al., 1994; Bown et al., 2002; Holmberg et al., 2003; Engbaek and Lawson, 2004; Tea et al., 2004), 37.2% in South Africa (Pretorius et al., 2004), 6–43.5% in Asia (Bai et al., 2002; Castle et al., 2004; Li et al., 2004; Bai et al., 2005; Kim et al., 2005; Winoto et al., 2005; Inoue et al., 2008) and 42.2–57% in North America (Kosoy et al., 1997; Jardine et al., 2005). Although the discrepancy of prevalence of Bartonella infection in vari-ous studies has not been well explained, it is reasonable to hypothesize that different ecological environments may
favour different rodent populations; and thus diverse Bartonella species could be observed in different geographical areas and in different species of small mammals.
The major objectives of this study were to determine the prevalence of Bartonella infections in small mammals in Taiwan, and to characterize Bartonella isolates obtained from these animals at the species level by molecular methods. The information in this study will be useful to develop control strategies and diagnostic procedures for Bartonella infections in humans in Taiwan.
Materials and Methods Sample collection
During the period of August 2002 and November 2004, a total of 310 rodents and shrews (169 R. norvegicus, 126 Suncus murinus, 10 Rattus rattus, 3 Rattus losea, and 2 Mus musculus,) were captured in the Taichung area in central Taiwan. The Taichung area comprises Taichung County (coastal and sub-urban areas) and Taichung City, which is completely surrounded by the County. The ani-mals were trapped from several sites with three different environmental characteristics, including harbour areas in coastal region, dairy cattle farms in the sub-urban area and traditional markets in the urban area. After being humanely anesthetized with zoletil 50 (Virbac Laborato-ries, 06516 Carros, France), the animals were bled to death via cardiac puncture by using 3-ml syringes fitted with 22-gauge, 1.5-inch needles. The blood was then collected in an EDTA tube and stored at )80C for further isolation and molecular identification of Bartonella species.
Blood culture for Bartonella species
A total of 310 whole blood specimens collected from rodents and shrews were used for Bartonella isolation. For bacterial culture, 200 ll of thawed whole blood sample were plated onto chocolate agar. The plates were incu-bated at 35C in 5% CO2 for at least 1 month and
checked for growth of Bartonella species on a weekly basis. For the suspected plates, at least two colonies were randomly selected and separately sub-cultured onto dif-ferent fresh agar plates for further molecular identification of Bartonella species by PCR/RFLP (polymerase chain reaction/restriction fragment length polymorphism) and sequence analysis.
DNA extraction and PCR/RFLP procedures for Bartonella species
After culturing from a single colony pick from the origi-nal plate, DNA of the cultured isolates was extracted
using Viogene DNA/RNA Extraction Kit (Viogene Biotek Corp., Taipei, Taiwan) following the manufacturer’s instructions. The primers BhCS.781p and BhCS.1137n were used first for amplifying a fragment ranging from 380-bp to 400-bp of the partial gltA gene of Bartonella species following the procedures developed by Norman et al. (1995). Reaction mixtures of PCR were set up as follows: 5 ll of DNA template, 0.5 ll of 100 lm each pri-mer, 4 ll of 2.5 mm dNTPs, 5 ll of 10· PCR buffer, 3 ll of 25 mm MgCl2, 31.75 ll of sterile distilled H2O and
DNA polymerase 0.25 ll (Ampli Gold, Applied Biosys-tems, Foster City, CA, USA). Primers bartsppA and bart-sppB amplified a fragment of the 16S/23S rRNA intergenic spacer region (ITS) by single-step PCR (Jensen et al., 2000); the different molecular size of the PCR products allowed for a quick differentiation of various Bartonella species. Restriction fragment length polymor-phism analysis (RFLP) of the gltA gene was also per-formed for quick identification of Bartonella organisms at species level with restriction enzymes TaqI (New England BioLabs., Beverly, MA, USA), HhaI (New England Bio-Labs) and MseI (New England BioBio-Labs) following the manufacturer’s instructions.
Sequencing and phylogenetic analyses of Bartonella species
The confirmed PCR products were sent for automated sequencing (Mission Biotech, Taipei, Taiwan). By phylo-genetic analysis, the sequences obtained from the isolates were compared to the sequences of Bartonella type strains, including Bartonella alsatica (IBS382T) CIP 105477, Bartonella birtlesii (IBS 325T) CIP 106294, Barto-nella bovis (91-4T) CIP 106692, BartoBarto-nella clarridgeiae (Houston-2T) ATCC 51734, B. doshiae (R18T) NCTC 12862, B. elizabethae (F9251T) ATCC 49927, B. grahamii (V2T) NCTC 12860 b, Bartonella henselae (Houston-1T) ATCC 49882, Bartonella koehlerae (C-29T) ATCC 700693, Bartonella quintana (FullerT) ATCC VR-358, B. taylorii (M6T) NCTC 12861, B. tribocorum (IBS 506T) CIP 104576, B. vinsonii subsp. arupensis (OK 94-513T) ATCC 700727, B. vinsonii subsp. berkhoffii (93-CO1T) ATCC 51672, B. vinsonii subsp. vinsonii (BakerT) ATCC VR-152. The sequences of the Bartonella isolates were analysed first using the blastn program of the NCBI website to identify the closest Bartonella species in the Entrez Nucleo-tide database. Then, after the sequences were aligned by the Clustal W method from the BioEdit program (Tom Hall, Ibis Biosciences, Isis Pharmaceuticals, Carlsbad, CA, USA), phylogenetic analysis was performed on the aligned DNA sequences using maximum parsimony as imple-mented in phylip version 3.6 (Joseph Felsenstein, Depart-ment of Genome Sciences and DepartDepart-ment of Biology,
WA, USA). Bootstrap support was calculated by using 1000 bootstrap data replicates as implemented by Seqboot in the phylip program version 3.6. The sequences of the gltA gene of the strains used in this study have been sub-mitted to the Genbank. The obtained accession numbers are serial numbers from FJ179374 to FJ179394.
Indirect immunofluorescence antibody test
The bacterial antigens for indirect immunofluorescence antibody test (IFA) to determine antibody titres included B. tribocorum, B. grahamii, B. elizabethae and a unique Bartonella strain MLE053 (closely related to B. tribocorum) isolated from S. munrinus in Taiwan. Each type strain was cultured on chocolate agar plate at 35C in 5% CO2 for
4 days to grow up a confluent plate of bacteria. Then the IFA slides were made as described previously (Chang et al., 2006). The slides were kept at)70C for storage.
For IFA testing, the frozen sera were thawed at room temperature and treated at 56C for 30 min for heat inac-tivation. The serum samples were serially diluted from 1 : 32 to 1 : 512 by twofold dilutions using PBS (with 10% skim milk). Thirty microlitres of the diluted serum samples were dropped onto each well of slides prepared earlier. The slides were incubated at 37C for 40 min and then washed with PBS for 10 min. The secondary anti-bodies used for serological testing were fluorescein-labelled goat anti-rat immunoglobulin G (Kirkegaard Perry Laboratories Inc., Gaithersburg, MD, USA). They were diluted at 1 : 400 in PBS with 5% milk containing 0.001% Evan’s blue, and the mixture was applied to each well. The slides were incubated at 37C for 40 min, then washed with PBS for 10 min, and washed again with dou-ble distilled water for 10 min prior to reading with a fluorescent microscope (magnification, ·400). The inten-sity of the bacillus-specific fluorescence was scored subjec-tively from 1 to 4. The previous study (Kosoy et al., 1997) has shown that only 1.5% of the 394 tested rodents were with an antibody titre ‡1 : 32 by IFA test; therefore, in this study, a seropositive animal was defined as the fluorescence score of ‡2 at dilution of 1 : 32. Milk in PBS without serum was always applied to each slide as a negative control.
Statistical analysis
The data were managed using microsoft office excel 2003 and analysed with EpiInfo version 3.3.2 (Center for Disease Control and Prevention, Atlanta, GA, USA). The chi-square test for homogeneity was used to evaluate if the prevalence of bacteremia is significantly different among the groups. A P-value less than 0.05 is considered to be statistically significant.
Results
Isolation of Bartonella species
Among the 310 small mammals tested, Bartonella organ-isms were isolated from 128 (41.3%) animals using whole blood culture. Despite the limited sample sizes for R. losea, M. musculus and R. rattus, prevalence of Barto-nella bactermia varied among the different animal species, as shown in Table 1. Rattus norvegicus were the most frequently trapped animals, and 52.7% of them were Bartonella bacteremic. It was determined that 28.6% of the shrews (Suncus murinus) was Bartonella bacteremic. Although only three R. losea were tested, bartonellae were isolated from two of them. Bartonella organism was also isolated from a R. rattus. The prevalence of Bartonella bacteremia was significantly different in three sampling environments, ranging from 56.2% in farms, 38.6% in harbour area and 11.8% in urban environment (P < 0.05). Such an observation was also identified in the population of R. norvegicus rats.
Molecular characterization of Bartonella isolates
As shown in Fig. 1, the isolates were characterized by the molecular patterns of the combined results of PCR of the 16S/23S ITS region (three patterns: A, B, and C) and PCR/RFLP of the gltA gene with HhaI (three patterns: A, B, and C), TaqI (one pattern: A) and MseI (four patterns: A, B, C, and D) digestion. It was identified a total of seven molecular patterns, named as AAAA, AAAB, AAAC, ACAA, ABAA, BAAA and CAAD. Several isolates for each molecular pattern were selected and sequenced for com-parison. After sequencing and phylogenetic analysis of the gltA gene (Table 2 and Fig. 2), the isolate was found to be close to five Bartonella species. The sequences of the gltA gene of the strains used in this study have been sub-mitted to the Genbank. The obtained accession numbers are serial numbers from FJ179374 to FJ179394. The iso-lates with molecular patterns ABAA and BAAA, which showed as two separate linages in the phylogenetic rela-tionship, were closest to B. tribocorum with 96.3–99.6% of DNA similarity. Two molecular patterns AAAB and
AAAC were closest to B. grahamii (DNA similarity value: 93.6%-95.4%). The isolates with AAAA pattern and ACAA pattern were closest to B. elizabethae (96.6–96.9% of DNA similarity) and B. rattimassiliensis (98.4–99.6% of DNA similarity), respectively. Although the isolate with CAAD pattern was shown to be close to B. taylorii (92.1% of DNA similarity) by phylogenetic analysis, the sequence of the isolate was much closer to B. phoceensis with 94.0% similarity after BLASTN analysis. The isolates close to B. rattimassilensis, B, tribocorum, B. grahamii, B. elizabethae and B. phoceensis were isolated from R. nor-vegicus, and the ones close to B. tribocorum and B. eliza-bethae were the most prevalent. On the contrary, most (97.2%) of S. murinus were infected with isolates close to B. tribocorum. Several R. norvegicus rats were identified to
Table 1. Prevalence (%) of Bartonella bac-teremia by whole blood culture in small mammals from three environments in Taichung, Taiwan
Animal species
Sampling environments
Harbour Farm Urban Total Rattus norvegicus 51.6 (47/91) 60.6 (40/66) 16.7 (2/12) 52.7 (89/169) Suncus murinus 28.8 (36/125) 0.0 (0/1) – 28.6 (36/126) Rattus losea 66.7 (2/3) – – 66.7 (2/3) Mus musculus 0.0 (0/1) 0.0 (0/1) – 0.0 (0/2) Rattus rattus – 20.0 (1/5) 0.0 (0/5) 10.0 (1/10) Total 38.6 (85/220) 56.2 (41/73) 11.8 (2/17) 41.3 (128/310)
ITS gene Hha I
Taq I M 1 2 3 4 5 6 7 M 1 2 M A A B C A B C A C B D 3 4 5 6 7 M bp bp 100 200 300 400 500 1000 100 200 300 400 500 1000 1 2 3 4 5 6 7 M 1 2 3 4 5 6 7 M Mse I
Fig. 1. Combined PCR molecular patterns for the16S-23S intergenic spacer region and PCR/RFLP analysis by digestion of the gltA gene with HhaI, TaqI and MseI for the Bartonella isolates in Taiwan. Lane M, 100-bp DNA ladder; lanes 1, 2, 3, 4, 5, 5, 6, 7 are the selected isolates to show seven molecular patterns of AAAA, AAAB, AAAC, ACAA, ABAA, BAAA and CAAD, respectively.
be co-infected with different Bartonella species, including 10 animals with B. elizabethae-like and B. tribocorum-like organisms, and one animal with B. phoceensis-like and B. tribocorum-like organisms.
For the isolates with zoonotic potential, B. grahamii-like organisms were only isolated from animals in har-bour and farm areas. Bartonella elizabethae was identified in the three different sampling environments, yet only
one R. norvegicus rat from the urban environment was infected with B. elizabethae.
Serological test by indirect immunofluorescence antibody test
For serological testing, a total of four different Bartonella strains were used as antigens, including B. elizabethae,
Table 2. Prevalence (%) of Bartonella bacteremia by whole blood culture according to animal and Bartonella species, Taichung, Taiwan
Animal species
Percentage of Bartonella species
B. rattimassiliensis B. tribocorum B. grahamii B. elizabethae B. phoceensis Rattus norvegicus 1.1 (1/89) 64.0 (57/89) 9.0 (8/89) 34.8 (31/89) 3.4 (3/89) Suncus murinus 2.8 (1/36) 97.2 (35/36) 0 (0/36) 0 (0/36) 0 (0/36) Rattus rattus 0 (0/1) 100.0 (1/1) 0 (0/1) 0 (0/1) 0 (0/1) Rattus losea 0 (0/2) 0 (0/2) 50.0 (1/2) 50.0 (1/2) 0 (0/2)
Fig. 2. Phylogenetic analysis of Bartonella type strains and Bartonella spp. isolated from small mammals in Taiwan on the basis of partial DNA sequences of gltA gene. The phylogenetic relationship was constructed using the maximum parsimony method of phylip version 3.6 program, and bootstrap analysis was performed with 1000 trials of bootstrap data (confidence of bootstrap val-ues not shown if lower than 70%). The tree was rooted using Rhizobium meliloti as an outgroup reference. The closest Bartonella species for the molecular patterns were B. tribocorum for patterns of ABAA and BAAA, B. grahamii for patterns of AAAB and AAAC, B. elizabethae for the pattern of AAAA, B. rattimassiliensis for the pattern ACAA and B. phoceensis for the pattern of CAAD.
B. grahamii, B. tribocorum and the Bartonella strain MLE 053. The strain of MLE 053 was isolated from S. murinus and closest to B. tribocorum, but was shown to have an independent linage according to the result of phylogenetic analysis (Fig. 2). The result showed that percentages of presence of antibodies against B. elizabethae, B. grahamii, B. tribocorum and Bartonella strain MLE 053 were 0%, 3.2%, 5.2% and 3.2%, respectively.
Discussion
This is the first study conducted in Taiwan to understand the epidemiology of Bartonella infections in small mam-mals. Geographically, the study area is located North of 24o latitude North and about 120.5olongitude East, with The Central Mountain Range at its East and the Taiwan Strait at its west. Although Taiwan is located in the sub-tropical areas in Asia, Taichung has a milder climate than any other parts in Taiwan, with an annual average tem-perature of 23C and humidity of 80%. The results indi-cated that the prevalence of Bartonella bacteremia animals was as high as 41.3%. Moreover, isolates close to B. eliza-bethae and B. grahamii, which have been recognized as human pathogens, were identified in these small mam-mals in central Taiwan. Of major importance, 34.8% of the 89 R. norvegicus rats with Bartonella bacteremia was found to be B. elizabethae carriers. These findings strongly suggest that rodents and shrews in Taiwan may serve as important reservoirs of Bartonella species; therefore humans living in this area should be aware of possible transmission from these animals. To the best of our knowledge, this is the first report to demonstrate the presence of the zoonotic B. elizabethae and B. grahamii in lesser rice-field rats, R. losea. This rodent species is also found in Vietnam, Thailand, Laos and southeastern coastal region of China.
In Asia, several studies have shown that small mam-mals, mainly rodents, are important reservoirs for various Bartonella species (Bai et al., 2002; Winoto et al., 2005; Bai et al., 2007; Inoue et al., 2008). Our results further indicated that the prevalence of Bartonella infection was significantly different in small mammals from various sampling sites in Taiwan. Overall, the lowest prevalence was identified in the urban environment; a result similar to the previous findings in Japan (Inoue et al., 2008). It is still unclear why animals from the farm areas were with the highest probability of acquiring Bartonella organisms. We reasonably hypothesized that the ecological diversity in farm areas may favour the survival of vectors for Bartonella transmission. Further studies still need to be conducted to validate this hypothesis.
Taiwan is located in East Asia and is an island with marine tropical climate. However, the Tropic of Cancer
(23.5¢N) running across its middle section divides the island into two regions, one with the tropical monsoon climate in the South and the other with subtropical monsoon climate in the North. The diverse climate and the Central Mountain along the island result in unique ecological environment that sustain various living crea-tures. Bartonella species in small mammals were the clos-est to at least five different Bartonella species, including B. rattimassiliensis, B. tribocorum, B. grahamii, B. elizabet-hae and B. phoceensis. A similar result is found in Japan before by Inoue et al. (2008). Although the vectors responsible for some of these Bartonella species have been identified in recent studies, including fleas and mites (Bown et al., 2004; Kim et al., 2005; Loftis et al., 2006; Marie´ et al., 2006; Abbot et al., 2007), it will be of major interest to elucidate which vectors are responsible for Bartonella transmission in Taiwan. Furthermore, the result of this study implied that Bartonella organisms may have host preference, which is similar to results reported from other parts of the world (Birtles et al., 1994; Kosoy et al., 1997, 2000). In Taiwan, R. norvegicus seems to be capable reservoirs for various Bartonella spe-cies. On the contrary, the majority of the S. murinus was infected with only one Bartonella species, closest to B. tribocorum. One possible reason to explain this dis-crepancy is that these two animals belong to two differ-ent families (R. norvegicus in the Muridae family and S. murinus in the Soricidae family), and the other possi-ble reason is that the infested vectors could also be different for these two animal species.
A previous study has demonstrated that most of the rodents with Bartonella bacteremia had low antibody titres against various Bartonella antigens (Kosoy et al., 1997), suggesting that these animals may serve as com-petent reservoirs for Bartonella species in nature. In our study, four different Bartonella strains that were isolated from animals in most areas were used as antigens for serological testing. Comparing to the high prevalences of Bartonella bacteremia, percentages of seropositivity were fairly low in the tested animals. Of major importance, none of the animals was seropositive for B. elizabethae. As a result, our data not only strongly suggested that small mammals are competent reservoirs for these Bartonella species, but also indicated that serological testing may not be an appropriate tool for epidemio-logical investigation in small mammals, especially for B. elizabethae.
In conclusion, people should be aware that small mam-mals in Taiwan are reservoirs for Bartonella species, espe-cially for the zoonotic B. elizabethae and B. grahamii. Further studies need to be conducted to determine whether these agents would be responsible for human cases with unknown fever or febrile illness in Taiwan.
Acknowledgements
This project was supported by grants of DOH 95-DC1035 from the Department of Health, Taiwan and NSC 95-2313-B-005-028-MY2 from the National Science Council, Taiwan. The authors also thank Kuo-Lin Liu and Chin-Hsien Wang, who are working in the Third Branch Office, Centers for Disease Control, for their kind assis-tance to collect blood specimens from small mammals cap-tured in the Taichung Harbor and Mai-Liao Harbor areas.
References
Abbot, P., A. E. Aviles, L. Eller, and L. A. Durden, 2007: Mixed infections, cryptic diversity, and vector-borne patho-gens: evidence from Polygenis fleas and Bartonella species. Appl. Environ. Microbiol. 73, 6045–6052.
Bai, Y., M. Y. Kosoy, G. O. Maupin, K. R. Tsuchiya, and K. L. Gage, 2002: Genetic and ecologic characteristics of
Bartonella communities in rodents in southern China. Am. J. Trop. Med. Hyg. 66, 622–627.
Bai, H. M., F. L. Yang, H. Yang, and Q. Zhang, 2005: Study on Bartonella species in rodents in western Yunnan, China. Zhonghua Liu Xing Bing Xue Za Zhi 26, 868–870.
Bai, Y., S. P. Montgomery, K. W. Sheff, M. A. Chowdhury, R. F. Breiman, H. Kabeya, and M. Y. Kosoy, 2007: Bartonella strains in small mammals from Dhaka, Bangladesh, related to Bartonella in America and Europe. Am. J. Trop. Med. Hyg. 77, 567–570.
Baker, J. A., 1946: A rickettsial infection in Canadian voles. J. Exp. Med. 84, 37–50.
Birtles, R. J., T. G. Harrison, and D. H. Molyneux, 1994: Grahamella in small woodland mammals in the U.K.: isolation, prevalence and host specificity. Ann. Trop. Med. Parasitol. 88, 317–327.
Birtles, R. J., T. G. Harrison, N. A. Saunders, and D. H. Molyneux, 1995: Proposals to unify the genera Grahamella and Bartonella, with descriptions of Bartonella talpae comb. nov., Bartonella peromysci comb. nov., and three new species, Bartonella grahamii sp. nov., Bartonella taylorii sp. nov., and Bartonella doshiae sp. nov. Int. J. Syst. Bacteriol. 45, 1–8.
Birtles, R. J., J. Canales, P. Ventosilla, E. Alvarez, H. Guerra, A. Llanos-Cuentas, D. Raoult, N. Doshi, and T. G. Harrison, 1999: Survey of Bartonella species infecting intradomicillary animals in the Huayllacalla´n Valley, Ancash, Peru, a region endemic for human bartonellosis. Am. J. Trop. Med. Hyg. 60, 799–805.
Bown, K. J., B. A. Ellis, R. J. Birtles, L. A. Durden, J. Lello, M. Begon, and M. Bennett, 2002: New world origins for haemoparasites infecting United Kingdom grey squirrels (Sciurus carolinensis), as revealed by phylogenetic analysis of bartonella infecting squirrel populations in England and the United States. Epidemiol. Infect. 129, 647–653.
Bown, K. J., M. Bennett, and M. Begon, 2004: Flea-borne Bartonella grahamii and Bartonella taylorii in bank voles. Emerg. Infect. Dis. 10, 684–687.
Castle, K. T., M. Kosoy, K. Lerdthusnee, L. Phelan, Y. Bai, K. L. Gage, W. Leepitakrat, T. Monkanna, N. Khlaimanee, K. Chandranoi, J. W. Jones, and R. E. Coleman, 2004: Prevalence and diversity of Bartonella in rodents of northern Thailand: a comparison with Bartonella in rodents from southern China. Am. J. Trop. Med. Hyg. 70, 429–433. Chang, C. C., C. C. Lee, S. Maruyama, J. W. Lin, and M. J. Pan,
2006: Cat scratch disease in veterinary-associated populations and in its cat reservoir in Taiwan. Vet. Res. 37, 565–577. Comer, J. A., C. Flynn, R. L. Regnery, D. Vlahov, and J. E.
Childs, 1996: Antibodies to Bartonella species in inner-city intravenous drug users in Baltimore, MD. Arch. Intern. Med. 156, 2491–2495.
Daly, J. S., M. G. Worthington, D. J. Brenner, C. W. Moss, D. G. Hollis, R. S. Weyant, A. G. Steigerwalt, R. E. Weaver, M. I. Daneshvar, and S. P. O’Connor, 1993: Rochalimaea eliza-bethae sp. nov. isolated from a patient with endocarditis. J. Clin. Microbiol. 31, 872–881.
Ellis, B. A., R. L. Regnery, L. Beati, F. Bacellar, M. Rood, G. G. Glass, E. Marston, T. G. Ksiazek, D. Jones, and J. E. Childs, 1999: Rats of the genus Rattus are reservoir hosts for patho-genic Bartonella species: an Old World origin for a New World disease? J. Infect. Dis. 180, 220–224.
Engbaek, K., and P. A. Lawson, 2004: Identification of Barto-nella species in rodents, shrews and cats in Denmark: detec-tion of two B. henselae variants, one in cats and the other in the long-tailed field mouse. APMIS 112, 336–341.
Gundi, V. A., B. Davoust, A. Khamis, M. Boni, D. Raoult, and B. La Scola, 2004: Isolation of Bartonella rattimassiliensis sp. nov. and Bartonella phoceensis sp. nov. from European Rattus norvegicus. J. Clin. Microbiol. 42, 3816–3818. Heller, R., P. Riegel, Y. Hansmann, G. Delacour, D. Bermond,
C. Dehio, F. Lamarque, H. Monteil, B. Chomel, and Y. Pie´-mont, 1998: Bartonella tribocorum sp. nov., a new Bartonella species isolated from the blood of wild rats. Int. J. Syst. Bacteriol. 48, 1333–1339.
Holmberg, M., J. N. Mills, S. McGill, G. Benjamin, and B. A. Ellis, 2003: Bartonella infection in sylvatic small mammals of central Sweden. Epidemiol. Infect. 130, 149–157.
Inoue, K., S. Maruyama, H. Kabeya, N. Yamada, N. Ohashi, Y. Sato, M. Yukawa, T. Masuzawa, F. Kawamori, T. Kadosaka, N. Takada, H. Fujita, and H. Kawabata, 2008: Prevalence and genetic diversity of Bartonella species isolated from wild rodents in Japan. Appl. Environ. Microbiol. 74, 5086–5092. Jardine, C., G. Appleyard, M. Y. Kosoy, D. McColl, M.
Chiri-no-Trejo, G. Wobeser, and F. A. Leighton, 2005: Rodent-associated Bartonella in Saskatchewan, Canada. Vector Borne Zoonotic. Dis. 5, 402–409.
Jensen, W. A., M. Z. Fall, J. Rooney, D. L. Kordick, and E. B. Breitschwerdt, 2000: Rapid identification and differentiation of Bartonella species using a single-step PCR assay. J. Clin. Microbiol. 38, 1717–1722.
Kerkhoff, F. T., A. M. Bergmans, A. van Der Zee, and A. Rothova, 1999: Demonstration of Bartonella grahamii DNA in ocular fluids of a patient with neuroretinitis. J. Clin. Microbiol. 37, 4034–4038.
Kim, C. M., J. Y. Kim, Y. H. Yi, M. J. Lee, M. R. Cho, D. H. Shah, T. A. Klein, H. C. Kim, J. W. Song, S. T. Chong, M. L. O’Guinn, J. S. Lee, I. Y. Lee, J. H. Park, and J. S. Chae, 2005: Detection of Bartonella species from ticks, mites and small mammals in Korea. J. Vet. Sci. 6, 327–334.
Kosoy, M. Y., R. L. Regnery, T. Tzianabos, E. L. Marston, D. C. Jones, D. Green, G. O. Maupin, J. G. Olson, and J. E. Childs, 1997: Distribution, diversity, and host specificity of Bartonella in rodents from the Southeastern United States. Am. J. Trop. Med. Hyg. 57, 578–588.
Kosoy, M. Y., E. K. Saito, D. Green, E. L. Marston, D. C. Jones, and J. E. Childs, 2000: Experimental evidence of host specificity of Bartonella infection in rodents. Comp. Immu-nol. Microbiol. Infect. Dis. 23, 221–238.
Kosoy, M., M. Murray, R. D. Gilmore, Y. Bai Jr, and K. L. Gage, 2003: Bartonella strains from ground squirrels are identical to Bartonella washoensis isolated from a human patient. J. Clin. Microbiol. 41, 645–650.
Li, D. M., D. Z. Yu, Q. Y. Liu, and Z. D. Gong, 2004: Study on the prevalence of Bartonella species in rodent hosts from different environmental areas in Yunnan. Zhonghua Liu Xing Bing Xue Za Zhi 25, 934–937.
Loftis, A. D., W. K. Reeves, D. E. Szumlas, M. M. Abbassy, I. M. Helmy, J. R. Moriarity, and G. A. Dasch, 2006: Surveil-lance of Egyptian fleas for agents of public health signifi-cance: Anaplasma, Bartonella, Coxiella, Ehrlichia, Rickettsia, and Yersinia pestis. Am. J. Trop. Med. Hyg. 75, 41–48. Marie´, J. L., P. E. Fournier, J. M. Rolain, S. Briolant, B.
Dav-oust, and D. Raoult, 2006: Molecular detection of Bartonella quintana, B. elizabethae, B. koehlerae, B. doshiae, B. taylorii,
and Rickettsia felis in rodent fleas collected in Kabul, Afghanistan. Am. J. Trop. Med. Hyg. 74, 436–439. Maurin, M., R. Birtles, and D. Raoult, 1997: Current
knowl-edge of Bartonella species. Eur. J. Clin. Microbiol. Infect. Dis. 16, 487–506.
Norman, A. F., R. Regnery, P. Jameson, C. Greene, and D. C. Krause, 1995: Differentiation of Bartonella-like isolates at the species level by PCR-restriction fragment length poly-morphism in the citrate synthase gene. J. Clin. Microbiol. 33, 1797–1803.
Pretorius, A. M., L. Beati, and R. J. Birtles, 2004: Diversity of bartonellae associated with small mammals inhabiting Free State province, South Africa. Int. J. Syst. Evol. Microbiol. 54, 1959–1967.
Serratrice, J., J. M. Rolain, B. Granel, N. Ene, J. Conrath, J. F. Avierinos, P. Disdier, D. Raoult, and P. J. Weiller, 2003: Bilateral retinal artery branch occlusions
revealing Bartonella grahamii infection. Rev. Med. Interne 24, 629–630.
Tea, A., S. Alexiou-Daniel, A. Papoutsi, A. Papa, and A. Antoniadis, 2004: Bartonella species isolated from rodents, Greece. Emerg. Infect. Dis. 10, 963–964.
Welch, D. F., K. C. Carroll, E. K. Hofmeister, D. H. Persing, D. A. Robison, A. G. Steigerwalt, and D. J. Brenner, 1999: Isolation of a new subspecies, Bartonella vinsonii subsp. arupensis, from a cattle rancher: identity with isolates found in conjunction with Borrelia burgdorferi and Babesia microti among naturally infected mice. J. Clin. Microbiol. 37, 2598– 2601.
Winoto, I. L., H. Goethert, I. N. Ibrahim, I. Yuniherlina, C. Stoops, I. Susanti, W. Kania, J. D. Maguire, M. J. Bangs, S. R. Telford III, and C. Wongsrichanalai, 2005: Bartonella species in rodents and shrews in the greater Jakarta area. Southeast Asian J. Trop. Med. Public Health 36, 1523–1529.
