Babesia duncani

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Record number: 
Adverse Occurrence type: 
MPHO Type: 
Estimated frequency: 
Rare; only 3 cases reported in literature (September 2016).
Time to detection: 
130 days
Alerting signals, symptoms, evidence of occurrence: 
Immunosuppressed, multi-transfused (over a 10 year time period) recipient with sickle disease, autoinfarcted spleen and several month history of declining health and increasing transfusion requirements, presented with frequent evaluations for weakness, fatigue, shortness of breath and darkening of urine. Laboratory testing showed evidence of hemolysis with elevated bilirubin and reticulocytosis. Eventually he was diagnosed with babesiosis when his blood smears were noted to contact intraerythrocytic parasites and Maltese cross forms in up to 12% of RBCs. Review of previous blood smears showed intraerythrocytic parasites as early as 2 months prior. He was treated with RBC exchange and appropriate antibiotics. CDC investigation showed the source of the infection to be Babesia duncani by DNA sequencing.
Demonstration of imputability or root cause: 
Investigation of 38 donors found one donor to be positive with B. duncani IFA, with titers as high as 1:4096. B. duncani was also isolated by inoculating jirds (Mongolian gerbils) with a blood specimen taken more than 10 months after the index donation. Donor was healthy with extensive history of outdoor hiking and mountain biking in Washington, British Columbia, Wyoming, Montana and Idaho. A history of tick bites was confirmed.
Imputability grade: 
3 Definite/Certain/Proven
Suggest new keywords: 
Babesiosis duncani,
Reference attachment: 
Suggest references: 
The third described case of transfusion-transmitted Babesia duncani. Bloch EM et al. Transfusion. 52(7):1517-22, 2012 Jul. Herwaldt BL, Kjemtrup AM, Conrad PA, et al. (1997). Transfusion-transmitted babesia in Washington State: first reported case caused by a WA1-type parasite. J Infect Dis 175:1259-1262 Kjemtrup AM, Lee B, Fritz CL, et al. (2002) Investigation of transfusion transmission of a WA1-type babesial parasite to a premature infant in California. Transfusion 42;1482-1487.
Expert comments for publication: 
This is a rare case of transfusion transmitted Babesia duncani diagnosed 4 months after the implicated transfusion from a donor with known risk factors for tick exposure. Testing of the patient and donor confirmed B. duncani by DNA sequencing (recipient), IFA and inoculation of jirds (donor).