Detection of Ehrlichia platys in dogs in Australia

Objective To describe the detection of Ehrlichia platys in free-roaming dog s in Central Australia. Procedure Blood samples were collected from four dogs and examined for bact erial 16S ribosomal DNA using Polymerase Chain Reaction (PCR)-based assays. The three positive samples obtained were then sequenced and identification of the PCR product carried out. As a result of all three samples being ide ntical to or closely related to part of the 16S rRNA gene of E platys, bloo d samples were subsequently obtained from a further 24 dogs. These samples were screened using a PCR-assay to determine the presence of Ehrlichia DNA using genus-specific primers. The positive samples obtained from the screen ing process were then subjected to a further PCR-assay using E platys speci fic primers. Results Of 28 dogs sampled, Ehrlichia DNA was detected in the blood of 13 d ogs. Sequencing of the amplicons obtained indicated a high homology with th e 16S rRNA gene for E platys. When the E platys-specific PCR was performed for 10 of those dogs, the 678 bp product obtained from the PCR amplificatio n confirmed the identification as part of the 16S rRNA gene of E platys in all 10 dogs. Conclusion This study reports for the first time Ehrlichia carriage by dogs in Australia. It also indicates the usefulness of the PCR technique in rap idly and accurately identifying diseases that are otherwise difficult to de tect. By using universal primers directed against bacterial 16S ribosomal D NA and sequencing analysis, the detection of potentially pathogenic Ehrlich ia organisms that had not previously been found in Australia has been made possible.