Bartonella henselae as a cause of acute-onset febrile illness in cats

Breitschwerdt, Edward B; Broadhurst, Jack J; Cherry, Natalie A

Optimal monitoring of cats previously diagnosed with bartonellosis has not be established and further studies are needed. However, we recommend that follow-up serology and enrichment culture/PCR testing be considered to confirm therapeutic elimination of the infection. Post-treatment decreases in antibody levels seem to support elimination of infection in dogs. 42 However, in a dog experimentally infected with B henselae, IFAs were no longer detectable after administration of corticosteroids (no antibiotic treatment administered), yet B henselae was isolated from the bone marrow. 43 Based upon human case experiences, obtaining three specimens for enrichment blood culture/PCR within a 7 day period increased sensitivity of Bartonella species detection (odds ratio 3.4; P = 0.02), 44 and in no instance was a patient enrichment culture/PCR positive in all three specimens and only 3/12 patients were positive for two specimens. This finding, potentially related to a relapsing bacteremia as reported in cats, 4 indicates that diagnostic confirmation and subsequently proving therapeutic elimination of bartonellosis remains clinically and diagnostically challenging. Until additional studies define an optimal treatment regimen for feline bartonellosis, combination therapy is recommended for culture or PCR confirmed cases. As optimal treatment regimens, including dual therapy, are not proven to eliminate Bartonella species bacteremia in cats, it is important to attempt to lessen potential transmission by maintaining stringent flea control. 8, 9 Conclusions We conclude that B henselae causes acute febrile illness in cats that resolves in conjunction with antibiotic therapy, which may or may not represent elimination of infection. Neutropenia may be an accompanying haematological abnormality in a subset of cats with bartonellosis. Additional laboratory and field studies are needed to define optimal treatment regimens and optimal followup testing procedures for cats with bartonellosis.