Comparison of Anaplasma and Ehrlichia species-specific peptide ELISAs with whole organism-based immunofluorescent assays for serologic diagnosis of anaplasmosis and ehrlichiosis in dogs

To compare the performance of 5 synthetic peptide-based ELISAs with that of 3 commercially available immunofluorescent assays (IFAs) for serologic diagnosis of anaplasmosis and ehrlichiosis in dogs. A convenience set of 109 serum samples obtained before and at various times after inoculation for 23 dogs that were experimentally infected with , or and 1 uninfected control dog in previous studies. All serum samples were assessed with 5 synthetic peptide-based ELISAs designed to detect antibodies against , and and 3 whole organism-based IFAs designed to detect antibodies against , and The species-specific seroreactivity, cross-reactivity with the other tick-borne pathogens (TBPs), and diagnostic sensitivity and specificity were calculated for each assay and compared among assays. All serum samples obtained from dogs experimentally infected with a TBP yielded positive results on a serologic assay specific for that pathogen. In general, sensitivity was comparable between ELISAs and IFAs and tended to increase with duration after inoculation. Compared with the IFAs, the corresponding ELISAs were highly specific and rarely cross-reacted with antibodies against other TBPs. Results suggested that peptide-based ELISAs had enhanced specificity relative to whole organism-based IFAs for detection of antibodies against and spp, which should facilitate accurate diagnosis and may help detect dogs coinfected with multiple TBPs.