患者，男，65岁，农民，河北人。2021年8月12日因“无明显诱因间断发热”至当地医院就诊，血常规示全血细胞减少，被误诊为血液系统疾病，予抗感染治疗、琥珀酸亚铁补充造血原料等治疗后，症状暂时好转但病情反复，多次住院治疗长达6月余。2022年2月19日再次出现发热，体温最高达39 ℃，遂至河北省人民医院进一步诊治。患者既往有流浪犬接触史，白蛉叮咬吸血史不详。入院查体：贫血貌，腹软，肝、脾处质稍硬。血常规示：白细胞计数0.72 × 10⁹/L，中性粒细胞0.34 × 10⁹/L，淋巴细胞0.30 × 10⁹/L，红细胞计数3.03 × 10¹²/L，血红蛋白72.00 g/L，血小板计数46.00 × 10⁹/L。免疫学检测示：免疫球蛋白G 32.9 g/L，补体C3 0.53 g/L，补体C4 0.095 g/L，补体C1q 144.6 mg/L，直接抗人球蛋白抗IgG阳性，抗核抗体为阳性。相关病原体检测示：真菌D-葡聚糖814.0 pg/ml，人类疱疹病毒4型（HHV-4）PCR < 500拷贝/ml。胸、腹部CT及腹部彩超示脾大，脾内可见片状低密度影，边界欠清。骨髓穿刺涂片示：部分巨噬细胞浆内及其周围可见杜氏利什曼原虫无鞭毛体。全血样品外送至江苏先声医学诊断有限公司行宏基因组第二代测序，检出利什曼原虫DNA序列数共266 335条，其中婴儿利什曼原虫145 767条，杜氏利什曼原虫66 243条，恰氏利什曼原虫53 461条，同时检出HHV-4 28条。结合临床症状和实验室检查结果，诊断为杜氏利什曼原虫感染。给予静脉两性霉素B，5 mg起并逐渐增加至100 mg，治疗3 d后患者体温下降，1周后体温正常，后转入专科医院继续治疗20 d后出院。约3个月后随访，患者自诉无任何不适，骨髓穿刺涂片未见利什曼原虫。

A 65-year-old male patient, who was a farmer from Hebei, went to the local hospital for “intermittent fever of unknown origin” on August 12, 2021, and his blood test showed pancytopenia, which was misdiagnosed as a blood system disease, after antibiotic treatment, ferrous succinate supplementation for restoring hematopoietic deficiencies. The symptoms were improved temporarily, but his condition recurred, and the patient was hospitalised for more than 6 months. On February 19, 2022, he developed a fever again, with a body temperature of up to 39 °C, and was admitted to Hebei Provincial People’s Hospital for further diagnosis and treatment. The patient has a history of previous contact with street dogs. The history of blood-sucking sandfly bites exposure is unknown. The admission examination showed anemia appearance, soft abdomen, liver and spleen slightly hard. Blood count showed that the white blood cell count was 0.72 × 10⁹/L, the neutrophils count was 0.34 × 10⁹/L, the lymphocytes count was 0.30 × 10⁹/L, the red blood cell count was 3.03 × 10¹²/L, the hemoglobin level was 72 g/L, the platelet count was 46.00 × 10⁹/L. Immunological tests showed that immunoglobulin G level was 32.9 g/L, complement C3 was 0.53 g/L, complement C4 was 0.095 g/L, complement C1q was 144.6 mg/L, direct anti-human globulin was positive for IgG and positive for antinuclear antibodies. Relevant pathogens were tested. The fungus D-dextran was 814.0 pg/ml, human herpesvirus type 4 (HHV-4) PCR was below 500 copies/ml. The chest and abdominal CT and ultrasound showed splenomegaly and flaky low-density shadows could be seen in the spleen, with unclear boundaries. Bone marrow aspiration smear showed Leishmania donovalii in and around some macrophages without flagellates. The whole blood samples were sent to Jiangsu Simcere Medical Diagnostics Co., Ltd. for metagenomic second-generation sequencing. A total of 266 335 Leishmania DNA sequences were detected, including 145 767 L. infantiles, 66 243 L. donovalii, 53 461 L. dononii and 28 HHV-4 lesions. Combined with clinical symptoms and laboratory findings, L. donovalii infection diagnosis was made. Intravenous amphotericin B was administrated, starting from 5 mg to 100 mg and gradually ramping up the treatment, the patient’s body temperature decreased after 3 days of treatment, and the body temperature was normal after 1 week. The patient was and then transferred to a specialist hospital for 20 days of continuous treatment before discharged. After about 3 months of follow-up, the patient reported no discomfort and no leishmania on the bone marrow aspiration smear.