title: Cyclic CD8+ lymphopenia in dogs experimentally infected with Bartonella vinsonii subsp. berkhoffii.
abstract: 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.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
authors.forename: B L
authors.initials: BL
authors.lastname: Pappalardo
authors.forename: T
authors.initials: T
authors.lastname: Brown
authors.forename: D
authors.initials: D
authors.lastname: Gebhardt
authors.forename: S
authors.initials: S
authors.lastname: Sontakke
authors.forename: E B
authors.initials: EB
authors.lastname: Breitschwerdt
mesh_terms: D000818:Animals; D001474:Bartonella Infections / Q000150:complications / Q000662:veterinary*; D016516:CD4-CD8 Ratio; D018414:CD8-Positive T-Lymphocytes; D002469:Cell Separation / Q000662:veterinary; D004195:Disease Models, Animal; D004283:Dog Diseases / Q000097:blood / Q000382:microbiology*; D004285:Dogs; D005434:Flow Cytometry / Q000662:veterinary; D007958:Leukocyte Count / Q000662:veterinary; D008231:Lymphopenia / Q000209:etiology / Q000382:microbiology / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000662:veterinary