No abstract

Using PCR in conjunction with pre-enrichment culture, we detected Bartonella henselae and B. vinsonii subspecies berkhoffii in the blood of 14 immunocompetent persons who had frequent animal contact and arthropod exposure.

Bacteria of the genus Bartonella, a member of the Alphaproteobacteria, are fastidious, gram-negative, aerobic bacilli that comprise numerous species, subspecies, and subtypes. In human and veterinary medicine, species isolation remains a vital component of the diagnostic and therapeutic management of Bartonella infection. We describe a novel, chemically modified, insect-based liquid culture medium that supports the growth of at least seven Bartonella species. This medium will also support cocultures consisting of different Bartonella species, and it facilitated the primary isolation of Bartonella henselae from blood and aqueous fluid of naturally infected cats. This liquid growth medium may provide an advantage over conventional direct blood agar plating for the diagnostic confirmation of bartonellosis.Due to their zoonotic potential, their vector transmission, which includes sandflies, lice, fleas, and ticks, and their frequent adaptation to a mammalian reservoir host, Bartonella species are considered among the newest and most significant emerging pathogens (1,3,8,12,27,29,39,45). These bacteria are highly adapted to a mammalian reservoir host; further, these organisms have been shown to cause a long-lasting intraerythrocytic bacteremia in both humans and animals (11,14,22,24,25,37). Bartonella species are also the causative agents of Carrion's disease (Oroya fever and verruga peruana) (Bartonella bacilliformis) (6), trench fever (B. quintana) (11,40,43), endocarditis (B. elizabethae, B. henselae, B. vinsonii subsp. berkhoffii, B. washoensis, B. clarridgeae) (3, 7, 9, 16, 17, 21, 40, 44), bacillary angiomatosis in immunocompromised patients (B. quintana, B. henselae) (14,30,48), neuroretinitis (B. grahamii) (28), and cat scratch disease (B. henselae, B. clarridgeiae) (5,31,42).Because Bartonella species frequently induce persistent intravascular infections, it has been difficult to attribute chronic disease causation to infection in humans and companion animals; much of this difficulty may be related to the few and often very subtle clinical abnormalities that are reported by a patient or observed in a sick animal. Confirming disease causation is especially difficult in retrospective or prospective animal studies in which Bartonella bacteremia can be detected in overtly healthy, natural reservoir hosts-a paradigm in opposition to Koch's postulates for disease causation (12, 23). Nevertheless, an increasingly diverse spectrum of Bartonella-associated infections have been recognized in people and in dogs due to the development of new approaches to improving serologic and molecular diagnostic testing methods, which prove to be, in most instances, more sensitive than conventional culture methods for the isolation of Bartonella species (13,15,26,30,33,38,41,46,49). Primary isolation of Bartonella species following lysis centrifugation, or freezing of a blood sample, followed by application to a blood agar plate, is the most widely used method for the microbiological diagnosis of bartonellosis. Isolation of Bartonel...

Lyme disease is the most frequently reported human vector-associated disease in the United States. Infection occurs after the bite of an Ixodid tick that is infected with Borrelia burgdorferi. Dogs have often been reported to serve as effective sentinel animals to assess the risk of human B. burgdorferi infection. Based on published data of human Lyme disease case numbers and our clinical impressions, we hypothesized that canine exposure to B. burgdorferi would be lower in North Carolina when compared to the exposure in Virginia, Maryland, and Pennsylvania. To address this hypothesis, we evaluated B. burgdorferi exposure status utilizing a specific and sensitive C6 peptide-based enzyme-linked immunosorbent assay. Our convenience sample included 1,666 canine serum samples submitted to the Vector Borne Disease Diagnostic Laboratory from North Carolina (n = 987), Virginia (n = 472), Maryland (n = 167), and Pennsylvania (n = 40). Comparisons among states were made using the Chi-square test or the Fisher's exact test; p-values were adjusted for multiple comparisons using the Bonferroni correction. A Chi-square test for trend was used to determine if there was an increase in the frequency of seroreactors associated with the geographical origin of the samples. The proportion of seroreactive dogs in North Carolina was markedly lower (p < 0.008) than that observed in dogs from Virginia, Maryland, and Pennsylvania. These results support the hypothesis that B. burgdorferi transmission seems to occur infrequently in North Carolina dogs as compared to dogs residing in other southeastern and mid-Atlantic states. Furthermore, they support the utility of dogs as a sentinel to characterize the risk of B. burgdorferi transmission to humans in a defined geographical location.

Bartonella species, transmitted by arthropods or animal bites and scratches, are emerging pathogens in human and veterinary medicine. PCR and DNA sequencing were used to test oral swabs collected from dogs. Results indicated the presence of 4 Bartonella species: B. bovis, B. henselae, B. quintana, and B. vinsonii subspecies berkhoffii.

Background: Although lymphoma is the most common neoplastic process reported in dogs, its precise etiology is unknown. Golden Retrievers are more likely to develop lymphoma, suggesting a breed predisposition; however, other factors, including environment, immunity, and infection, are likely contributors to oncogenesis. Hypothesis: We hypothesized that the development of lymphoma in Golden Retrievers may be associated with vector‐borne infections, specifically Bartonella, Anaplasma, or Ehrlichia species infections. Animals: Golden Retrievers with lymphoma and healthy Golden Retrievers from across the United States were recruited for study participation. Methods: A matched, case‐control study was performed to determine the association of lymphoma and the presence of Bartonella, Anaplasma, and Ehrlichia species in serum, blood, and lymph node aspirates. Results: Using PCR analyses and DNA sequencing, single and coinfections with Bartonella henselae, Bartonella elizabethae, Bartonella quintana, and/or Bartonella vinsonii (berkhoffii) were detected in the blood and lymph node aspirates of Golden Retrievers with lymphoma (5/28 dogs, 18%) and in healthy Golden Retrievers (10/56 dogs, 18%); no Anaplasma or Ehrlichia DNA was detected in any dog. When compared with dogs with lymphoma, a higher (P <.001) proportion of healthy Golden Retrievers were receiving monthly acaricide treatments (2.6 times higher). Conclusions and Clinical Importance: Bartonella DNA can be detected in blood and lymph nodes; importantly, in this report, Bartonella was detected in the same proportion of clinically healthy dogs and dogs with lymphoma. Longitudinal studies should be conducted to determine the mode of transmission of Bartonella in dogs, whether lymphatic infection is persistent, or whether these bacteria may contribute to the development of lymphoma.

B. henselae is implicated as a possible cause or a cofactor in the development of pyogranulomatous lymphadenitis in dogs. In dogs with pyogranulomatous lymphadenitis, immunofluorescent assays may not detect antibodies against B. henselae. Molecular testing, including PCR assay of affected tissues, may provide an alternative diagnostic method for detection of B. henselae DNA in pyogranulomatous lymph nodes.

Lyme disease is the most frequently reported human vector-associated disease in the United States. Infection occurs after the bite of an Ixodid tick that is infected with Borrelia burgdorferi. Dogs have often been reported to serve as effective sentinel animals to assess the risk of human B. burgdorferi infection. Based on published data of human Lyme disease case numbers and our clinical impressions, we hypothesized that canine exposure to B. burgdorferi would be lower in North Carolina when compared to the exposure in Virginia, Maryland, and Pennsylvania. To address this hypothesis, we evaluated B. burgdorferi exposure status utilizing a specific and sensitive C6 peptide-based enzyme-linked immunosorbent assay. Our convenience sample included 1,666 canine serum samples submitted to the Vector-Borne Disease Diagnostic Laboratory from North Carolina (n = 987), Virginia (n = 472), Maryland (n = 167), and Pennsylvania (n = 40). Comparisons among states were made using the Chisquare test or the Fisher's exact test; p-values were adjusted for multiple comparisons using the Bonferroni correction. A Chi-square test for trend was used to determine if there was an increase in the frequency of seroreactors associated with the geographical origin of the samples. The proportion of seroreactive dogs in North Carolina was markedly lower (p < 0.008) than that observed in dogs from Virginia, Maryland, and Pennsylvania. These results support the hypothesis that B. burgdorferi transmission seems to occur infrequently in North Carolina dogs as compared to dogs residing in other southeastern and mid-Atlantic states. Furthermore, they support the utility of dogs as a sentinel to characterize the risk of B. burgdorferi transmission to humans in a defined geographical location.