Bartonella infection linked to eye inflammation in a dog

Abstract

A 2-year old, neutered, female spaniel mixed breed was referred to the North Carolina State University Veterinary Teaching Hospital for evaluation of bilateral anterior uveitis. The dog was febrile and, in addition to anterior uveitis, multifocal hyporeflective lesions were present in the tapetal fundus of both eyes. The antibody titer for Bartonella vinsonii subspecies berkhoffi was positive (1 : 512). Aqueous paracentesis was performed for PCR in an attempt to detect B. vinsonii in the eye but was unsuccessful. The ocular manifestations of Bartonella infection in humans are currently expanding as more sensitive serologic and PCR techniques are being developed to identify Bartonella spp. In addition to optic neuritis and neuroretinitis, retinochoroidal lesions are one of the most common manifestations of B. henselae infection, and are frequently accompanied by vitreous or anterior segment inflammation. Diagnosis of a Bartonella infection in humans can be made on serology alone, in conjunction with ocular examination findings. The ultimate proof of B. vinsonii (berkhoffi) as a direct cause of ocular disease would be detection of the infectious agent in the eye. However, it is unknown at this time whether Bartonella causes ocular disease primarily, secondarily via an autoimmune reaction, or both. Due to the difficulties associated with culture of Bartonella spp. and the limitations of PCR, serology is currently the most useful tool for screening dogs for possible Bartonella spp. infection. In the case presented here, even though the PCR was negative, the clinical signs of anterior uveitis and choroiditis might reasonably be associated with B. vinsonii (berkhoffi) seroreactivity, which was repeatable on three separate occasions. Clinical improvement was also accompanied by a post-treatment decrease in B. vinsonii (berkhoffi) seroreactivity, potentially supporting resolution of Bartonella infection in this dog. This is the first reported case of a possible association between uveitis, choroiditis and Bartonella infection in the dog, without clinical manifestations of other organ or tissue involvement. Future studies based on PCR analysis of intraocular fluids may clarify the involvement of B. vinsonii (berkhoffi) in dogs with intraocular inflammatory disease. Furthermore, performing fluorescein angiography in dogs with elevated Bartonella titers may also prove useful in the identification and characterization of lesions.