2015 ACVIM Forum Research Abstract Program

Ehrlichia ewingii infection transmitted by A. americanum is common in Oklahoma. The agreement between the 2 laboratories was good even though some discordant results were detected with the second laboratory appearing to have a higher sensitivity for E. ewingii DNA. However, 100% concordance was not expected because the samples were not handled identically and the assays use different technologies. The sequence homology between E. ewingii and E. chaffeensis is very high and so a different result from two different sequencing laboratories can occur. Alternately, dog may have had dual infection. Babesia conradae is a small, intraerythrocytic piroplasm found in dogs from southern California. In domestic dogs, B. conradae infection causes lethargy and hemolytic anemia. In March 2014 a greyhound used to hunt coyotes in Oklahoma presented with lethargy and pale mucous membranes. Evaluation of stained blood film revealed small piroplasms in red blood cells. Subsequent DNA extraction of whole blood, PCR amplification using piroplasm-specific primers, and DNA sequencing confirmed infection by B. conradae. The index case dog was euthanized by the owner due to deteriorating condition. Follow-up evaluation of the majority of dogs in the owner's kennel revealed that 3 of 6 (50%) greyhounds and 0 of 4 (0%) walker hounds were PCR positive for infection with B. conradae. No dogs were known to have travel histories west of Oklahoma. Two of the greyhounds subclinically infected with B. conradae were treated with an 8 day course of azithromycin (10 mg/kg [4.5 mg/lb], PO, q 24 hour) plus atovaquone (13.3 mg/kg [6 mg/lb], PO, q 8 hour). The third B. conradae-infected dog was sold and lost to follow-up. Approximately 1 month after completion of azithromycin and atovaquone treatment, both dogs were PCR negative for infection with B. conradae. To the authors' knowledge, this is the first report of B. conradae in dogs outside of California.