Detection of Bartonella spp. in dogs after infection with Rickettsia rickettsii.

ABSTRACT: BACKGROUND:Dynamics of infection by Bartonella and Rickettsia species, which are epidemiologically associated in dogs, have not been explored in a controlled setting. OBJECTIVES:Describe an outbreak investigation of occult Bartonella spp. infection among a group of dogs, discovered after experimentally induced Rickettsia rickettsii (Rr) infection. ANIMALS:Six apparently healthy purpose-bred Beagles obtained from a commercial vendor. METHODS:Retrospective and prospective study. Dogs were serially tested for Bartonella spp. and Rr using serology, culture, and PCR, over 3 study phases: 3?months before inoculation with Rr (retrospective), 6?weeks after inoculation with Rr (retrospective), and 8?months of follow-up (prospective). RESULTS:Before Rr infection, 1 dog was Bartonella henselae (Bh) immunofluorescent antibody assay (IFA) seroreactive and 1 was Rickettsia spp. IFA seroreactive. After inoculation with Rr, all dogs developed mild Rocky Mountain spotted fever compatible with low-dose Rr infection, seroconverted to Rickettsia spp. within 4-11?days, and recovered within 1?week. When 1 dog developed ear tip vasculitis with intra-lesional Bh, an investigation of Bartonella spp. infection was undertaken. All dogs had seroconverted to 1-3 Bartonella spp. between 7 and 18?days after Rr inoculation. Between 4 and 8?months after Rr inoculation, Bh DNA was amplified from multiple tissues from 2 dogs, and Bartonella vinsonii subsp. berkhoffii (Bvb) DNA was amplified from 4 of 5 dogs' oral swabs. CONCLUSIONS AND CLINICAL IMPORTANCE:Vector-borne disease exposure was demonstrated in research dogs from a commercial vendor. Despite limitations, our results support the possibilities of recrudescence of chronic subclinical Bartonella spp. infection after Rr infection and horizontal direct-contact transmission between dogs.

SUBMITTER: Lashnits E 

PROVIDER: S-EPMC6979086 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature