Huang Xin-An, Xiang Rong, Liao Ru-He, Luan Yu-Bo, Zhao Yi-Lin, Yang Ji-Hu, Luo Chun-Feng, Huang Lin, Xia Luo-Yuan, Zhu Dai-Yun, Sun Yi, Wang Lei, Jiang Jia-Fu
Artemisinin Research Center, Guangzhou University of Chinese Medicine, Guangzhou, 510000, People's Republic of China.
State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, 100071, People's Republic of China.
Infect Dis Poverty. 2025 Jun 10;14(1):45. doi: 10.1186/s40249-025-01311-x.
Human babesiosis, caused by intraerythrocytic protozoa of the genus Babesia (Piroplasmida, Babesiidae), is a globally emerging zoonosis transmitted primarily through Ixodes spp. ticks. Babesia microti, which is endemic particularly in the northeastern and midwestern United States, accounts for the majority of globally reported human cases. Recent studies highlight its spread to non-traditional regions and cross-border transmission, driven by climate change, blood transfusions and increased human mobility. Despite increasing reports of autochthonous B. microti infections in certain areas of China, imported cases remain critically underrecognized due to overlapping clinical manifestations with malaria and limited diagnostic awareness.
We report a diagnostically challenging case of acute B. microti infection in a 52-year-old Chinese woman, presenting with a sudden recurrent fever (39.0-41.0 °C), hemolytic anemia (hemoglobin 104 g/L), thrombocytopenia (platelet 78 × 10 /L) and splenic hypodense lesions on July 11, 2023, seven days after returning from a 14-day visit to rural Wisconsin, United States. Peripheral blood smears demonstrated characteristic intraerythrocytic ring forms (parasitemia: 7800 organisms/μl) and pathognomonic "Maltese cross" tetrads. Polymerase chain reaction (PCR) targeting the 18S rRNA gene confirmed B. microti infection (GenBank No. PP087232), showing 99.8% identity with the US-type strain Gray (AY693840) and the sequence obtained from a US travel-acquired case in Singapore (MK609547). The patient received intravenous clindamycin (600 mg twice daily), oral dihydroartemisinin (80 mg twice daily), packed red blood cell transfusions, and supportive care, ultimately achieving full recovery after 17 days.
This study documented the first imported cases of human babesiosis in China, emphasizing the need for heightened clinical and public health vigilance. Screening travelers from endemic areas presenting with fever or hemolytic anemia for Babesia, bolstering molecular diagnosis, improving transfusion safety, and intensifying regional surveillance are crucial in reducing underdiagnosis and preventing transmission. These measures are essential for controlling babesiosis in China.
人巴贝斯虫病由巴贝斯属（梨形虫纲，巴贝斯虫科）的红细胞内原生动物引起，是一种全球范围内新出现的人畜共患病，主要通过硬蜱属蜱传播。微小巴贝斯虫尤其在美国东北部和中西部地区流行，占全球报告的人类病例的大多数。最近的研究强调，在气候变化、输血和人员流动性增加的推动下，它已传播到非传统地区并出现跨境传播。尽管中国某些地区本土微小巴贝斯虫感染的报告有所增加，但由于与疟疾的临床表现重叠以及诊断意识有限，输入性病例仍未得到充分认识。
我们报告了一例对诊断具有挑战性的急性微小巴贝斯虫感染病例，患者为一名52岁的中国女性，于2023年7月11日出现突发反复发热（39.0 - 41.0°C）、溶血性贫血（血红蛋白104 g/L）、血小板减少（血小板78×10⁹/L）和脾脏低密度病变，她在美国威斯康星州农村进行了14天访问后返回七天。外周血涂片显示特征性的红细胞内环形式（寄生虫血症：7800个生物体/μl）和具有诊断意义的“马耳他十字”四联体型。针对18S rRNA基因的聚合酶链反应（PCR）证实了微小巴贝斯虫感染（GenBank编号PP087232），与美国型菌株Gray（AY693840）以及从新加坡一例美国旅行获得性病例中获得的序列（MK609547）显示出99.8%的同一性。患者接受了静脉注射克林霉素（每日两次，每次600 mg）、口服双氢青蒿素（每日两次，每次80 mg）、输注浓缩红细胞以及支持性治疗，最终在17天后完全康复。
本研究记录了中国首例输入性人巴贝斯虫病病例，强调需要提高临床和公共卫生警惕性。对来自流行地区出现发热或溶血性贫血的旅行者进行巴贝斯虫筛查、加强分子诊断、提高输血安全性以及加强区域监测对于减少漏诊和预防传播至关重要。这些措施对于控制中国的巴贝斯虫病至关重要。
