@article{pappalardo_brown_tompkins_breitschwerdt_2001, title={Immunopathology of Bartonella vinsonii (berkhoffii) in experimentally infected dogs}, volume={83}, ISSN={["1873-2534"]}, DOI={10.1016/S0165-2427(01)00372-5}, abstractNote={Following natural infection with Bartonella, dogs and humans develop comparable disease manifestations including endocarditis, peliosis hepatis, and granulomatous disease. As the immunologic response to infection in these hosts has not been clearly established, data presented here was derived from the experimental infection of six specific pathogen free (SPF) beagles with a known pathogenic strain of Bartonella. Six dogs were inoculated intravenously with 10(9)cfu of B. vinsonii ssp. berkhoffii and six control dogs were injected intravenously with an equivalent volume of sterile saline. Despite production of substantial levels of specific antibody, blood culture and molecular analyses indicated that Bartonella established chronic infection in these dogs. Flow cytometric analysis of monocytes indicated impaired bacterial phagocytosis during chronic Bartonella infection. There was also a sustained decrease in the percentage of CD8+ lymphocytes in the peripheral blood. Moreover, modulation of adhesion molecule expression (downregulation of L-selectin, VLA-4, and LFA-1) on CD8+ lymphocytes suggested quantitative and qualitative impairment of this cell subset in Bartonella-infected dogs. When compared with control dogs, flow cytometric analysis of lymph node (LN) cells from B. vinsonii infected dogs revealed an expanded population of CD4+ T cells with an apparent naïve phenotype (CD45RA+/CD62L+/CD49D(dim)). However, fewer B cells from infected dogs expressed cell-surface MHC II, implicating impaired antigen presentation to helper T cells within LN. Taken together, results from this study indicate that B. vinsonii establishes chronic infection in dogs which may result in immune suppression characterized by defects in monocytic phagocytosis, an impaired subset of CD8+ T lymphocytes, and impaired antigen presentation within LN.}, number={3-4}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Pappalardo, BL and Brown, TT and Tompkins, M and Breitschwerdt, EB}, year={2001}, month={Dec}, pages={125–147} }
 @inbook{pappalardo_breitschwerdt_2000, title={Bartonella vinsonii infection in dogs}, ISBN={0721655238}, booktitle={Kirk's current veterinary therapy : small animal practice (13th Ed.)}, publisher={Philadelphia, PA : W.B. Saunders}, author={Pappalardo, B. L. and Breitschwerdt, E. B.}, year={2000}, pages={300} }
 @article{pappalardo_brown_gebhardt_sontakke_breitschwerdt_2000, title={Cyclic CD8+lymphopenia in dogs experimentally infected with Bartonella vinsonii subsp berkhoffii}, volume={75}, ISSN={["0165-2427"]}, DOI={10.1016/S0165-2427(00)00182-3}, abstractNote={Until recently, it was presumed that Bartonella vinsonii only infected voles, a species of North American rodents. In April of 1993, however, our laboratory isolated a novel subspecies of B. vinsonii (B. vinsonii subsp. berkhoffii) from the blood of a dog diagnosed with vegetative valvular endocarditis. Subsequently, based on a seroepidemiologic survey of dogs from North Carolina and Virginia presenting for a variety of medical problems, we found evidence supporting a potentially important association between B. vinsonii and Ehrlichia canis co-infection in dogs. In the following study, eight dogs were infected with B. vinsonii: four specific pathogen free dogs and four dogs that had previously been infected with E. canis. Flow cytometric analysis of peripheral blood lymphocytes revealed a cyclic elevation of the CD4/CD8 T-cell ratio that correlated with cyclic CD8+ lymphopenia in all dogs infected with B. vinsonii, regardless of prior exposure to E. canis.}, number={1-2}, journal={VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY}, author={Pappalardo, BL and Brown, T and Gebhardt, D and Sontakke, S and Breitschwerdt, EB}, year={2000}, month={Jun}, pages={43–57} }
 @article{pappalardo_brown_gookin_morrill_breitschwerdt_2000, title={Granulomatous disease associated with Bartonella infection in 2 dogs}, volume={14}, ISSN={["0891-6640"]}, DOI={10.1892/0891-6640(2000)014<0037:GDAWII>2.3.CO;2}, abstractNote={Shortly after removal of an engorged tick from the left ear, a 4-year-old Greyhound was referred for evaluation of fever and a rapidly enlarging mass in the region of the left submandibular lymph node. Histopathologic evaluation of the lymph node resulted in a diagnosis of severe granulomatous lymphadenitis. An 11-year-old mixed-breed dog was referred for evaluation of a 6-week history of serous nasal discharge. Histologic examination of a surgical biopsy from a nasal mass indicated multifocal granulomatous inflammation with fibrosis. Serum samples obtained from both dogs were reactive by immunofluorescent assay to Bartonella vinsonii subsp. berkhoffii antigens (reciprocal titers of 128). Although Bartonella organisms were not isolated by lysis centrifugation blood culture, Bartonella DNA was amplified from tissue samples obtained from each dog (lymph node biopsy from dog 1 and nasal biopsy from dog 2) using primers that amplify a portion of the 16S rRNA gene followed by Southern blot hybridization using a genus-specific probe. Additionally, restriction fragment length polymorphism (RFLP) analysis of a Bartonella-specific citrate synthase gene product obtained from dog 2 resulted in a restriction pattern identical to B. vinsonii subsp. berkhoffii. This is the 1st report of granulomatous disease in dogs associated with Bartonella infection.}, number={1}, journal={JOURNAL OF VETERINARY INTERNAL MEDICINE}, author={Pappalardo, BL and Brown, T and Gookin, JL and Morrill, CL and Breitschwerdt, EB}, year={2000}, pages={37–42} }
 @article{baneth_breitschwerdt_hegarty_pappalardo_ryan_1998, title={A survey of tick-borne bacteria and protozoa in naturally exposed dogs from Israel}, volume={74}, ISSN={["1873-2550"]}, DOI={10.1016/S0304-4017(97)00149-0}, abstractNote={Antibody reactivity against seven bacterial or protozoal pathogens was measured in sera derived from 40 dogs suspected of a tick-borne disease. Sera from 73% (29/40) of the dogs reacted with three or more test antigens. Seroreactivity was most prevalent to Babesia canis antigen (90%) followed by Babesia gibsoni (75%), Ehrlichia canis (63%), Rickettsia conorii--Moroccan strain (58%), Rickettsia conorii--Israeli strain no. 2 (28%), Borrelia burgdorferi (10%) or Bartonella vinsonii (berkhoffii) (10%). Seroconversion documented in seven dogs, supported an acute phase diagnosis of ehrlichiosis in four dogs, R. conorii infection in three dogs and babesiosis in one dog. In the remaining dogs, correlation of clinical abnormalities with increased seroreactivity was not established through the design of this study. Although Lyme borreliosis has not been reported in people in Israel, Western blot analysis for antibodies reactive to B. burgdorferi identified genus-specific antiflagellin antibodies indicating that dogs in Israel are exposed to a Borrelia species. Identification of species-specific seroreactivity was not possible and infection with a Borrelia species other than B. burgdorferi is likely. Seroreactivity to B. vinsonii (berkhoffii) in dogs outside the USA is reported here for the first time.}, number={2-4}, journal={VETERINARY PARASITOLOGY}, author={Baneth, G and Breitschwerdt, EB and Hegarty, BC and Pappalardo, B and Ryan, J}, year={1998}, month={Jan}, pages={133–142} }
 @article{pappalardo_correa_york_peat_breitschwerdt_1997, title={Epidemiologic evaluation of the risk factors associated with exposure and seroreactivity to Bartonella vinsonii in dogs}, volume={58}, number={5}, journal={American Journal of Veterinary Research}, author={Pappalardo, B. L. and Correa, M. T. and York, C. C. and Peat, C. Y. and Breitschwerdt, E. B.}, year={1997}, pages={467–471} }