Lookback investigations of <i>Babesia microti</i>–seropositive blood donors: seven‐year experience in a <i>Babesia</i>‐endemic area

Johnson, Stephanie T.; Cable, Ritchard G.; Leiby, David A.

doi:10.1111/j.1537-2995.2011.03345.x

Cited by 35 publications

(44 citation statements)

References 23 publications

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“…This is not new, having already been reported previously in both asymptomatic blood donors as well as patients following a diagnosis of acute babesiosis 10,14,15 Moritz et al recently reported on longitudinal follow-up of 262 seroreactive and/or PCR positive blood donors (from 2010 to 2015) using an arrayed fluorescent immunoassay (AFIA) and PCR. The median time to seroreversion was 410 days (range 24–1156) and among 129 donors followed to 1 year, 104 (81%) remained seroreactive.…”

Section: Discussionmentioning

confidence: 59%

A prospective evaluation of chronic Babesia microti infection in seroreactive blood donors

Bloch

Levin

Williamson³

et al. 2016

Transfusion

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BACKGROUND Babesia microti is the foremost infectious risk to the US blood supply for which an FDA licensed test is unavailable for donation screening. Characterization of the antibody response to B. microti and correlation with parasitemia is necessary to guide screening and donor management policies. STUDY DESIGN AND METHODS During an FDA-licensure trial, blood donors were prospectively screened (July-November 2013) using a B. microti-specific antibody enzyme immunoassay (EIA-Immunetics) in highly endemic (New York-NY; n=13,688), moderately endemic (Minnesota-MN; n=4,583) and non-endemic (New Mexico-NM; n=8,451) regions. Blood donors with repeat reactive (RR) results participated in a 12-month prospective cohort study using B. microti EIA, IFA, PCR, blood smear and clinical questionnaire. RESULTS Thirty-seven (61.67%) (24 NY, 7 MN, 6 NM) of 60 eligible RR donors enrolled in the study; 20/37 (54%) completed the 12-month follow-up visit of which 15 (75%) were still seroreactive. Nine PCR positive donors were identified during index screening; 5 participated in the follow-up study, 3 were PCR positive at 6 months and 2 remained positive at final follow-up (378 and 404 days). Most RR donors displayed low-level seroreactivity that was either stable or waning during follow-up. The level and pattern of reactivity correlated poorly with PCR positivity. CONCLUSION The findings indicate prolonged seropositivity in blood donors. Although rare, asymptomatic, persistent PCR positivity supports the current policy of indefinite deferral for donors with a history of babesiosis or positive test results. Repeat testing by PCR and serology will be necessary if reinstatement is to be considered.

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Section: Discussionmentioning

confidence: 59%

A prospective evaluation of chronic Babesia microti infection in seroreactive blood donors

Bloch

Levin

Williamson³

et al. 2016

Transfusion

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“…This finding suggests that subclinical infection persists in at least some donors for months if not longer, consistent with evidence presented in prior studies. 14,29 On the other hand, culling of EIA-reactive donors has been shown to decrease their prevalence in the donor population, 36 which may conceivably leave a preponderance of donors with new, seasonal infections.…”

Section: Discussionmentioning

confidence: 99%

Serologic screening of United States blood donors for Babesia microti using an investigational enzyme immunoassay

Levin

Williamson²,

Bloch

et al. 2016

Transfusion

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BACKGROUND The tick-borne pathogen Babesia microti has become recognized as the leading infectious risk associated with blood transfusion in the United States, yet no Food and Drug Administration–licensed screening tests are currently available to mitigate this risk. The aim of this study was to evaluate the performance of an investigational enzyme immunoassay (EIA) for B. microti as a screening test applied to endemic and nonendemic blood donor populations. STUDY DESIGN AND METHODS The study aimed to test 20,000 blood donors from areas of the United States considered endemic for B. microti and 10,000 donors from a nonendemic area with the investigational B. microti EIA. Repeat-reactive samples were retested by polymerase chain reaction (PCR), blood smear, immunofluorescent assay (IFA), and immunoblot assay. In parallel, serum samples from symptomatic patients with confirmed babesiosis were tested by EIA, IFA, and immunoblot assays. RESULTS A total of 38 of 13,757 (0.28%) of the donors from New York, 7 of 4583 (0.15%) from Minnesota, and 11 of 8363 (0.13%) from New Mexico were found repeat reactive by EIA. Nine of the 56 EIA repeat-reactive donors (eight from New York and one from Minnesota) were positive by PCR. The specificity of the assay in a nonendemic population was 99.93%. Among IFA-positive clinical babesiosis patients, the sensitivity of the assay was 91.1%. CONCLUSION The B. microti EIA detected PCR-positive, potentially infectious blood donors in an endemic population and exhibited high specificity among uninfected and unexposed individuals. The EIA promises to provide an effective tool for blood donor screening for B. microti in a format amenable to high-throughput and cost-effective screening.

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“…Unfortunately, none of these assays are 100% sensitive and specific in every phase of infection; PCR and microscopy are superior to IFA in the acute infection phase before an immune response has developed, but antibody-based assays are more likely to detect low-level infections in the late or chronic phases, when parasite loads are ex- tremely low (14,29,30,34,50). These low-level, largely asymptomatic infections are a particular concern for transfusiontransmitted babesiosis (19,20,23,24,53). In an effort to develop an improved antibody detection technique, we surveyed B. microti total antigen Western blots for reactive bands and identified an immunodominant antigen using detergent extraction and protein sequencing techniques.…”

Section: Discussionmentioning

confidence: 99%

“…The first human infections were identified among asplenic patients in Europe (1957) and among normosplenic residents of Nantucket Island, MA, in the United States (1970) (11,16,51,55). More recently, blood transfusions from otherwise healthy donors who harbor occult infections have been recognized as an important potential risk factor in disease transmission (1,12,19,23,32,53).…”

mentioning

confidence: 99%

“…However, antibody responses among the three dominant human pathogens of humans, B. microti, B. duncani, and B. divergens, appear to be species specific (7,14,17,18,41), and three separate assays would be required to conclusively rule out a diagnosis of infection with Babesia sp. PCR, while more sensitive than slide microscopy (29), has a reported limit of detection of 10 piroplasms per milliliter of whole blood (50% confidence interval) (57), and cases of transfusion-transmitted babesiosis have been documented from PCR-negative, antibody-positive blood donors (23,33,53).…”

mentioning

confidence: 99%

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Multiplex Assay Detection of Immunoglobulin G Antibodies That Recognize Babesia microti Antigens

Priest

Moss

Won

et al. 2012

Clin Vaccine Immunol

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Human babesiosis, a blood-borne infection caused by several species of Babesia, including B. microti, is an emerging disease that is endemic in the Northeast, upper Midwest, and Pacific Northwest regions of the United States. Risk factors for babesiosis include exposure to the infected tick vector and blood transfusions from infected donors. In this work, we cloned and expressed two of the immunodominant antigens from B. microti and used them in a multiplex bead format assay (MBA) to detect parasitespecific IgG responses in human sera. The MBA using recombinant B. microti secreted antigen 1 (BmSA1) protein was more specific (100%) and slightly more sensitive (98.7%) than the assay using a truncated recombinant BMN1-17 construct (97.6% and 97.4%, respectively). Although some antibody reactivity was observed among sera from confirmed-malaria patients, only one Plasmodium falciparum sample was simultaneously positive for IgG antibodies to both antigens. Neither antigen reacted with sera from babesiosis patients who were infected with Babesia species other than B. microti. Both positive and negative MBA results were reproducible between assays and between instruments. Additional studies of these recombinant antigens and of the multiplex bead assay using blood samples from clinically defined babesiosis patients and from blood donors are needed to more clearly define their usefulness as a blood screening assay.

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Lookback investigations of Babesia microti–seropositive blood donors: seven‐year experience in a Babesia‐endemic area

Cited by 35 publications

References 23 publications

A prospective evaluation of chronic Babesia microti infection in seroreactive blood donors

A prospective evaluation of chronic Babesia microti infection in seroreactive blood donors

Serologic screening of United States blood donors for Babesia microti using an investigational enzyme immunoassay

Multiplex Assay Detection of Immunoglobulin G Antibodies That Recognize Babesia microti Antigens

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