[目的]对不明原因的1例发热病例进行流行病学调查,明确诊断。[方法]通过现场流行病学调查了解病例的暴露史,通过实验室检测病例血象、特异性抗体和媒介病原。[结果]病例有高度的埃立克体的职业暴露史,血常规检测白细胞、血小板明显减少,血液人粒细胞埃立克体IgG抗体阳性,滴度为1∶60;从患者养殖耕牛身体捕获的蜱体检出埃立克体核酸。[结论]病例诊断为人粒细胞埃立克体病。 [Objective] To carry out epidemiological investigation of one case of fever with unknown cause and confirm the diagnosis. [Methods] Through field epidemiological investigation to understand the case history of exposure, blood samples detected by the laboratory, specific antibodies and vector pathogens. [Results] The patients had a high history of occupational exposure to Ehrlichia. Leukocytes and platelets were significantly reduced by blood tests. Erythrocyte IgG antibodies were positive for blood human granulocytes with a titer of 1:60. The captured ticks detected Ehrlichia nucleic acids. [Conclusion] The cases were diagnosed as human granulocytic ehrlichiosis.