Organism: Anaplasma phagocytophilium
The infection is transmitted from donor blood. The risk of infection can be reduced but not completely eliminated if:
(1) the blood is leukoreduced at the time of collection
(2) the donor is screened for febrile illness and/or a history of anaplasmosis
Diagnosis of transfusion-transmitted anaplasmosis:
(1) The patient receives a red blood cell transfusion.
(2) The donor lives in or has traveled to an endemic area.
(3) The patient becomes symptomatic within a few days after the transfusion (fever, headache, chills, myalgia, etc).
(4) Anaplasma are identified by PCR, serology or identification of cytoplasmic inclusions within neutrophils.
(5) Other sources of exposure to Anaplasmosis have been ruled out.
(6) There is not an alternative diagnosis that can explain the findings better.
Barriers to diagnosis:
(1) The patient is asymptomatic or has minor symptoms.
(2) The transfusion occurs in a nonendemic area.
(3) The patient gives a recent history of a tick bite.
(4) Diagnostic testing is not performed.
