Two-Step Polymerase Chain Reaction for Detection of Ehrlichia Platys in Canine Infectious Cyclic Thrombocytopenia

Canine infectious cyclic thrombocytopenia (CICT) is diagnosed by finding the basophilic inclusions within platelets on stained blood films. However, this method is unreliable, especially for detection at the chronic stage of infection. This report describes a two-step polymerase chain reaction (PCR) for detection of the etiologic agent of CICT. Two regions of the 16S rRNA gene sequence were used to amplify DNA specifically from Ehrlichia platys in blood specimens. All amplification reactions were run with the standard rapid cycling system. This technique was applied to 10 severely thrombocytopenic blood specimens collected from National Taiwan University Veterinary Hospital. Three of them were positive by two-step PCR amplification while only one is positive by Giemsa stained blood smear observation. The results indicate that this two-step PCR is a highly sensitive, specific, and efficient diagnostic method for detecting E. platys in clinical samples.