Tonnetti Laura, Townsend Rebecca L, Deisting Barbara M, Haynes James M, Dodd Roger Y, Stramer Susan L
Scientific Affairs, American Red Cross Holland Laboratory, Rockville, Maryland.
Transfusion. 2019 Feb;59(2):593-600. doi: 10.1111/trf.15043. Epub 2018 Nov 30.
Babesia microti, an intraerythrocytic parasite endemic in the Northeast and upper Midwest United States, is responsible for over 200 reported cases of transfusion-transmitted babesiosis (TTB). The American Red Cross has prospectively screened donations in endemic areas for B. microti since 2012.
Blood donation samples from Massachusetts, Connecticut, Minnesota, and Wisconsin were tested by arrayed fluorescence immunoassay and real-time polymerase chain reaction. Donors with reactive results by any test were deferred and invited to participate in a follow-up study.
Screening of 506,540 donations (June 2012-May 2018) yielded 1299 reactives, 177 of which were DNA and antibody positive and 25 DNA positive only. During the same time, 23 unscreened RBC units collected in Connecticut and Massachusetts were involved in TTB cases, making the risk of transmitting the infection from an unscreened donation in these two states 15.6-times greater than from a Babesia-negative unit. B. microti screening in Connecticut and Massachusetts has been associated with a reduction in TTB cases; none reported from blood donors residing in Connecticut since 2016. The positive donor rate has also decreased in Connecticut from 0.67% in 2013 to 0.23% in 2017. Ongoing follow-up testing has shown that only 10% of antibody-positive donors serorevert within 1 year, while 94% of polymerase chain reacton-positive donors become negative within 12 months.
Blood donation screening for B. microti in endemic areas effectively mitigates TTB risk. Screening should be considered for all areas demonstrating ongoing risk defined as clinical cases or positive blood donors including those associated with TTB cases.
微小巴贝斯虫是一种红细胞内寄生虫，在美国东北部和中西部上游地区流行，据报告它导致了200多例输血传播的巴贝斯虫病（TTB）。自2012年以来，美国红十字会一直在流行地区对献血进行前瞻性微小巴贝斯虫筛查。
对来自马萨诸塞州、康涅狄格州、明尼苏达州和威斯康星州的献血样本进行了阵列荧光免疫测定和实时聚合酶链反应检测。任何一项检测结果呈阳性的献血者被推迟献血，并被邀请参加一项随访研究。
对506,540份献血（2012年6月至2018年5月）进行筛查，发现1299份呈阳性反应，其中177份DNA和抗体均呈阳性，25份仅DNA呈阳性。同一时期，在康涅狄格州和马萨诸塞州采集的23个未经筛查的红细胞单位涉及TTB病例，这使得在这两个州未经筛查的献血传播感染的风险比来自巴贝斯虫阴性单位的风险高15.6倍。在康涅狄格州和马萨诸塞州进行的微小巴贝斯虫筛查与TTB病例的减少有关；自2016年以来，居住在康涅狄格州的献血者中未报告有TTB病例。康涅狄格州的阳性献血者率也从2013年的0.67%降至2017年的0.23%。正在进行的随访检测表明，只有10%的抗体阳性献血者在1年内血清反应转阴，而94%的聚合酶链反应阳性献血者在12个月内转为阴性。
在流行地区对献血进行微小巴贝斯虫筛查可有效降低TTB风险。对于所有显示持续存在风险（定义为临床病例或阳性献血者，包括与TTB病例相关的献血者）的地区，均应考虑进行筛查。
