| Summary: | 碩士 === 國立嘉義大學 === 獸醫學系研究所 === 94 === Nineteen canine blood samples that was suspected with ehrlichiosis were collected from animal hospitals in Taipei, Chiayi and Kaohsiung. And 107 canine blood samples from stray dogs were also collected randomly in southern Taiwan. Diagnostic methods for Ehrlichia spp. infection such as blood smear, indirect immunofluorescent antibody assay (IFA), enzyme- linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) were used in this study. The purpose of this study was to detecte Ehrlichia species of canine in Taiwan by using these laboratory diagnostic methods, and to compare their usage on clinical diagnosis. Ehrlichial morula were detected by blood smear, the positive rate of morular observed in mononuclear leukocytes was 1.6 % (2/126). The positive rate of morular observed in platelet was 4.0 % (5/126), and no morula were observed in granulocyte. Antibodies of Anaplasma phagocytophilum (A. phagocytophilum ) were detected by commercial IFA kit, the positive rate was 50.0 % (55/110). Antibodies of Ehrlichia canis (E. canis) were detected by commercial ELISA kit, the positive rate was 14.8 % (18/122). We also detected A. phagocytophilum and A. platys with PCR, the positive rates were 11.1 % (14/126) and 7.9 % (10/126), respectively. E. canis were also detected by nested PCR, all samples were negative in primary PCR, and the positive rates were 4.0 % (5/126) in nested PCR. All positive PCR products were sequenced, the results suggested that all sequences of positive PCR products that were amplified by primer ehr521-ehr790 were more similar to A. platys Israeli isolated strain (AY530806) than to A. phagocytophilum standard strain (AY055469). The sequences of 5 positive PCR products that were amplified by primer EC3-EC4 were identical to E. canis Taiwanese isolated strain (DQ228501), Japanese isolated strain (AF536827) and Chinese isolated strain (AF162860). The sequences of 10 positive PCR products that were amplified by primer EHR16SR-PLATYS were similar to AY530806 above 97.6 %. In 55 A. phagocytophilum positive samples which were detected with IFA kit, only 18.2 % (10/55) were also positive with PCR. In 18 E. canis positive samples which were detected with ELISA kit, only 11.1 % (2/18) were also positive with nested PCR. These results suggested that different diagnostic methods for ehrlichiosis, even though IFA and ELISA allowed advantages of less time consuming and easy to use. But positive results of antibodies maybe were remained by antigens stimulation in infected phase, or serologic cross-reactivity of other species of Ehrlichia. In conclusion, antigen detection with PCR might be a more accurate and specific method to diagnose ehrlichial infection in dogs in Taiwan.
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