Evaluation of Cytauxzoon felis infection status in captive-born wild felids housed in an area endemic for the pathogen.

OBJECTIVE: To determine whether apparently healthy captive-born wild felids that were not native to North America and were housed in an area endemic for Cytauxzoon felis harbored the pathogen. DESIGN: Prospective observational case series. ANIMALS: 11 captive-born wild felids that were (1 bobcat [Lynx rufus] and 1 cougar [Puma concolor]) or were not (1 lion [Panthera leo] and 8 tigers [Panthera tigris]) native to North America and 6 domestic cats (5 pets and 1 feral). PROCEDURES: Blood was collected, and a PCR assay for C felis was performed. The C felis 18S rRNA gene sequence was characterized in samples that tested positive. Blood smears were evaluated microscopically for intraerythrocytic organisms consistent with C felis. Blood smears from an additional 6 feral domestic cats found dead on the study premises were also evaluated. RESULTS: 4 tigers and 6 domestic cats without clinical signs of disease tested positive for C felis infection via PCR assay; intraerythrocytic organisms consistent with C felis were identified in smears from 1 C felis-infected tiger (which also had azotemia) and in smears from 11 of 12 domestic cats. Possible erythrocytic inclusions were identified in 1 tiger that tested negative for C felis. Sequences of C felis 18S rRNA amplicons from all infected tigers shared > 99.8% identity with reported C felis sequences from North American domestic cats and were identical to amplicons from domestic cats on the premises. CONCLUSIONS AND CLINICAL RELEVANCE: Captive tigers without clinical signs of disease tested positive for C felis. The PCR assay for C felis appeared to be more reliable than cytologic detection of piroplasms in tigers.

Re-emergence of Babesia conradae and effective treatment of infected dogs with atovaquone and azithromycin.

Babesia conradae (B. conradae) causes hemolytic anemia in dogs. This organism has not been reported clinically since it was originally described in southern California in 1991. To date, no anti-protozoal therapies have been associated with clearance of B. conradae. This report describes the use of atovaquone and azithromycin for the treatment of dogs naturally infected with B. conradae and report the re-emergence of B. conradae in southern California. Twelve dogs naturally infected with B. conradae were identified by practicing veterinarians and public health officials in southern California. Treatments consisted of a 10 day course of atovaquone (13.3mg/kg PO q 8h) and azithromycin (10-12.5mg/kg PO q 24h). Four dogs were treated in a randomized blinded placebo-controlled fashion, four additional cases were treated in a non-random, non-blinded fashion and one dog received no treatment. All dogs were tested for B. conradae DNA by polymerase chain reaction (PCR) initially and then once or 3 times post treatment (60-210 days). B. conradae infected dogs that received treatment did not have any detectable Babesia DNA by PCR after treatment. In contrast, dogs receiving placebo had detectable Babesia DNA by PCR throughout the study period. Combination therapy with atovaquone and azithromycin appears to be effective for acute and chronic babesiosis caused by B. conradae.