Human (Granulocytic) Anaplasmosis (HGA ... - Allina Health

TRANSFUSION-TRANSMITTED DISEASE
Cases of transfusion-transmitted HGA and babesiosis do occur. Anaplasma can survive for
more than one week in refrigerated blood. Leukoreduction reduces but does not eliminate the
risk of transmission for HGA. Babesia organisms may also survive in refrigerated blood, and
the transfusion-transmitted rate of babesiosis, thought to be higher than that of transfusiontransmitted
HGA, may be as high as 1 in 1800 red cell units. American Red Cross reports that
50% of recipients receiving Babesia-infected cellular products will demonstrate seroconversion.
There is sharing of blood products nationally, so the packed red cells your patient receives
may theoretically have come from anywhere in the United States. Some of the reasons
why it is so hard to eliminate the risk of an infected blood product include: It is difficult
to identify those donors who are infected before they become symptomatic or if they have
subclinical infection; some donors infected with Babesia may harbor the parasite for months
without overt symptoms; deferring donors during peak tick activity as potentially infected just
because they are from disease-endemic areas would severely limit blood supply with little potential
gain; and PCR testing of donors for HGA is cost prohibitive and felt to be of low yield.
Transfusion-transmitted HGA and/or Babesiosis should be considered in patients who develop
fever and thrombocytopenia post-transfusion. The incubation period before manifestation of
symptoms in HGA appears to be 7-10 days, similar to that of HGA disease transmitted by tick
bites. Symptom onset for Babesiosis is 1-9 weeks following the instigating tick bite; symptom
onset for Babesiosis due to an infected blood product is also thought to be 1-9 weeks, although
it may be shorter than for tick bites, presumably because more organisms are being
introduced. Please contact the associated Blood Bank and MDH immediately about any suspected
cases so that investigation can be undertaken.
As always, please be vigilantly mindful of risks versus benefits when prescribing blood products,
and make sure that you obtain informed consent from your patients.
Also, be aware that the American Red Cross (ARC) is currently undertaking a look-back study
to evaluate by IFA and PCR representative blood donations from high, moderate and low endemic
areas. 10,000 total blood donations from Minnesota/Wisconsin/upper Midwest
(considered a moderately endemic area by ARC) are reportedly going to be evaluated this
year. Donors whose products test positive will be notified, and recipient tracing will be undertaken.
If your patient is a recipient of one of these positive blood products, expect notification
through ARC or via the blood bank/pathologist.
9