Bartonella henselae Infections In An Owner and Two Papillon Dogs Exposed to Tropical Rat Mites (Ornithonyssus bacoti)

After raccoons were trapped and removed from under a house in New York, the owner and her two Papillon dogs became infested with numerous rat mites ( Ornithonyssus bacoti ). Two weeks later, both dogs developed pruritus, progressively severe vesicular lesions, focal areas of skin exfoliation, swelling of the vulva or prepuce, abdominal pain, and behavioral changes. Two months after the mite infestation, the owner was hospitalized because of lethargy, fatigue, uncontrollable panic attacks, depression, headaches, chills, swollen neck lymph nodes, and vesicular lesions at the mite bite sites. Due to ongoing illness, 3 months after the mite infestation, alcohol-stored mites and blood and serum from both dogs and the owner were submitted for Bartonella serology and Bartonella alpha Proteobacteria growth medium (BAPGM) enrichment blood culture/PCR. Bartonella henselae DNA was amplified and sequenced from blood or culture specimens derived from both dogs, the owner, and pooled rat mites. Following repeated treatments with doxycycline, both dogs eventually became B. henselae seronegative and blood culture negative and clinical signs resolved. In contrast, the woman was never B. henselae seroreactive, but was again PCR positive for B. henselae 20 months after the mite infestation, despite prior treatment with doxycycline. Clinicians and vector biologists should consider the possibility that rat mites may play a role in Bartonella spp. transmission.