Serology: B. vinsonii routinely measured, and B. henselae available shortly.

Culture—extremely difficult (almost impossible).

PCR—test that should be available soon.

Bartonella vinsonii
Doxycycline; Fluoroquinolones; Azithromycin; Aminoglycosides are also effective and can be used in critically ill, hospitalized cases.

Bartonella henselae
Azithromycin (Zithromax®, Pfizer) is needed.
Dose: 5-10 mg/kg q 24h for 7 d, then q 48h for 5 weeks.

Bartonella gibsoni
Combination Therapy with Azithromycin (Zithromax®, Pfizer). Dose: 10 mg/kg PO q 24h for 10 d + Atovaquone (Mepron®, Glaxo Wellcome). Dose:13.3 mg/kg PO q 8h for 10 d. Expensive, but a single atovaquone bottle contains enough drug to treat ~ 4 affected pit bull terriers.
[All dogs in the published study had failed imidazole and other treatments.]

B. canis and another Babesia-like organism have been isolated from cats with anemia in Spain. More likely to be found in FeLV- or FIV-infected cats. One cat with Babesia infection had recurrent episodes of AIHA, suspected to be from B. canis.

Anaplasma phagocytophila (formerly E. equi) infections in cats

Diagnosed in ~ 10 cats in the northeast US:

• Acute onset of illness:
• Anorexia, lethargy
• Febrile
• Thrombocytopenia
• PCR test positive for A. phagocytophila
• Respond rapidly to doxycycline

Cats with chronic anemia and maturation arrest

Ehrlichia/Anaplasma PCR test positive, but not yet speciated

Cats identified positive with PCR tests for E. canis-like organisms

Bartonella henselae and Neorickettsia rickettsii (formerly Rickettsia rickettsii) serologic cross-reactivity.

Many cats with antibody titers to B. henselae also have titers to N. rickettsii

Neorickettsia titers tend to be low (1:128, 1:256, 1:512); reason unclear, could be one-way cross-reactivity with reagent.

References:References: Birkenheuer et al, ACVIM Proc 2003, abstract; JAVMA 223:1306-1309, 2003. [Contributed by Dr. Ed Breitschwerdt]