Abstract: Objective To study pathological changes on Beagle dogs infected with Ehrlichia. Methods six beagle dogs that had been artificially infected with Ehrlichia were examined By using routine pathological methods. Results The obvious lesions were of subcutaneous hemorrhage and stagnation of blood in the major tissues and organs, and severe swollen enlargement in spleens and livers. The histopathological changes were characterized by accumulations of lymphocytes and plasma cells in blood vessels in livers, spleens, lungs and kidneys, and accumulations of lymphocytes and plasma cells in perivascular of livers. Conclusion The observation on pathological changes coincide mostly with reports abroad, but the macroscopic changes is more severe. This may contribute to the difference in pathogenicity of the strain in China.

Key words: Ehrlichia、Pathological observation, Beagle dog