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A longitudinal study of B abesia microti infection in seropositive blood donors
Author(s) -
Leiby David A.,
Johnson Stephanie T.,
Won Kimberly Y.,
Nace Eva K.,
Slemenda Susan B.,
Pieniazek Norman J.,
Cable Ritchard G.,
Herwaldt Barbara L.
Publication year - 2014
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/trf.12622
Subject(s) - parasitemia , medicine , seroprevalence , babesiosis , antibody , babesia , immunology , virology , biology , malaria , serology , plasmodium falciparum
Background B abesia infection is caused by intraerythrocytic tick‐borne parasites. Cases of transfusion‐transmitted babesiosis have been increasingly recognized. To date, no B abesia test has been licensed for screening US blood donors. We conducted a longitudinal study to assess the course and markers of B abesia infection among seropositive donors identified in a seroprevalence study. Study Design and Methods Eligible donors had B . microti indirect fluorescent antibody ( IFA ) titers of 64 or greater. Enrollees were monitored up to 3 years, by IFA and three methods for evidence of parasitemia: B . microti nested polymerase chain reaction ( PCR ) analysis (at two laboratories), hamster inoculation, and blood‐smear examination. Results Among 115 eligible donors, 84 (73%) enrolled. Eighteen enrollees (21%) had evidence of parasitemia for 30 total specimens (17% of 181), which were collected in 9 different months and tested positive by various approaches: PCR (25 specimens/16 persons), hamster inoculation (13 specimens/8 persons), and blood smear (one specimen positive by all three approaches). Overall, 14 persons had one or more specimen with positive PCR results at both laboratories (12 persons) and/or had parasitologically confirmed infection (eight persons). Three of nine persons who had more than one specimen with evidence of parasitemia had nonconsecutive positives. Several enrollees likely had been infected at least 1 year when their last positive specimen was collected. The final three specimens for seven persons tested negative by all study methods, including IFA . Conclusion Seropositive blood donors can have protracted low‐level parasitemia that is variably and intermittently detected by parasitologic and molecular methods. Donor‐screening algorithms should include serologic testing and not solely rely on molecular testing.