Bartonella spp

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Transmission electron micrograph of Bartonella vinsonii sub berkhoffii

Bartonella spp (formerly Rochalimaea) are a gram-negative, aerobic zoonotic hemotropic tick-borne parasitic proteobacteria of Asia[1] and the Americas[2].

These vector-borne pathogens infect erythrocytes, macrophages and endothelial cells in dogs, and cause vasoproliferative lesions by their migration[3]. The organisms are highly adaptive which enables them to persist within the cells of their mammalian hosts for extended periods[4]. Culturing the bacteria is often frustrating, as colonies can take up to 45 days to grow on enriched blood media.

Species which are pathogenic to dogs include:

  • Bartonella henselae
  • Bartonella vinsonii sub berkhoffii[5][6]
  • Bartonella merieuxii[7]
  • Bartonella koehlerae[8]
  • Bartonella rochalimae[9]
  • Bartonella clarridgeiae[10]
  • Bartonella washoensis[11]
  • Bartonella elizabethae[12]
  • Bartonella quintana[13]

The bacteria cause chronic persistent intracellular infections of host erythrocytes, macrophages, and vascular endothelial cells, and stimulate vasoproliferative lesions. Their intracellular location and immunomodulatory effects help them to avoid host immune responses.

Transmission is by the cat flea Ctenocephalides felis and ticks Ixodes pacificus and Rhipicephalus sanguineus[14].

Co-infections with Ehrlichia canis and Babesia canis is common. Additionally, 20% of adult ticks living in Bartonella-endemic regions of California have tested positive for Bartonella DNA.

The seroprevalence of B. vinsonii subsp. berkhoffii in dogs is usually low[15].

Clinical signs are variable and can range from asymptomatic infection to sudden death[16].

Nonspecific signs such as lethargy, weight loss, anorexia, and/or inappetance. Other signs of disease are less common and include granulomatous lymphadenopathy, granulomatous rhinitis, epistaxis, lameness, hind limb paresis, polyarthritis, cutaneous vasculitis, anterior uveitis, hyphema, chorioretinitis, anemia, thrombocytopenia, endocarditis with a predilection for the aortic valve, myocarditis, arrhythmias, cardiogenic pulmonary edema, collapse, seizures, meningoencephalitis and sudden death[17].

Diagnosis is based on isolation and identification of bacteria in tissue or blood samples, using light microscopy, ELISA, immunofluorescent antibodies (IFA) or PCR assays.

Treatment is usually effective with azithromycin, doxycycline and enrofloxacin.

Tick prevention is critical for control of the disease in endemic regions.

References

  1. Breitschwerdt EB (2005) Bartonellosis. In: Ettinger SJ, Feldman EC, editors. Textbook of Veterinary Internal Medicine: Diseases of the Dog and the Cat, 6th ed. St. Louis, Missouri: Elsevier Saunders; pp:636-637
  2. Chang CC, et al (2000) Coyotes (Canis latrans) as the Reservoir for a Human Pathogenic Bartonella sp.: Molecular Epidemiology of Bartonella vinsonii subsp. berkhoffii Infection in Coyotes from Central Coastal California. J Clin Microbiol 38:4193-4200
  3. Dehio C (2001) Bartonella interactions with endothelial cells and erythrocytes. Trends Microbiol 96:279–285
  4. Chomel BB et al (2006) Bartonella spp. in pets and effect on human health. Emerg Infect Dis 12:389–394
  5. Breitschwerdt EB, et al (1995) Endocarditis in a Dog Due to Infection with a Novel Bartonella Subspecies. J Clin Microbiol 33:154-160
  6. Guptill L (2003) Bartonellosis. Vet Clin Small Anim 33:809-825
  7. Chomel BB et al (2012) Candidatus Bartonella merieuxii, a Potential New Zoonotic Bartonella Species in Canids from Iraq. PLoS Negl Trop Dis 6(9):e1843
  8. Breitschwerdt EB et al (2010) PCR amplification of Bartonella koehlerae from human blood and enrichment blood cultures. Parasit Vectors 3:76
  9. Henn JB et al (2009) Infective endocarditis in a dog and the phylogenetic relationship of the associated "Bartonella rochalimae" strain with isolates from dogs, gray foxes, and a human. J Clin Microbiol 47(3):787-790
  10. Chomel, BB et al (2001) Aortic valve endocarditis in a dog due to Bartonella clarridgeiae. J Clin Microbiol 39:3548-3554
  11. Chomel, BB et al (2003) Isolation of Bartonella washoensis from a dog with mitral valve endocarditis. J Clin Microbiol 41:5327-5332
  12. Mexas, AM et al (2002) Bartonella henselae and Bartonella elizabethae as potential canine pathogens. J Clin Microbiol 40:4670-4674
  13. Kelly P et al (2006) Bartonella quintana endocarditis in dogs. Emerg Infect Dis 12(12):1869-1872
  14. Pappalardo BL, et al (1997) Epidemiologic evaluation of the risk factors associated with exposure and seroreactivity to Bartonella vinsonii in dogs. Am J Vet Res 58:467-471
  15. Breitschwerdt EB, et al (2004) Clinicopathological Abnormalities and Treatment Response in 24 Dogs Seroreactive to Bartonella vinsonii (berkhoffii) Antigens. J Am Anim Hosp Assoc 40:92-101
  16. Pappalardo BL, et al (2001) Immunopathology of Bartonella vinsonii (berkhoffii) in experimentally infected dogs. Vet Immunol Immunopathol 83:125-147
  17. MacDonald KA, et al (2004) A Prospective Study of Canine Infective Endocarditis in Northern California (1999-2001): Emergence of Bartonella as a Prevalent Etiologic Agent 18:56-64