Babesios infection

• An astute lab technician notes something bizarre on the blood smear, and a pathologist calls the ED (somehow finding the phone number, as this hasn't been done in some time) to report seeing this:

• The extracellular and intra-RBC purple dots represent either falciprum malaria or babesia microti

• Our patient hasn't traveled outside the US, and the preponderance of extracellular organisms makes malaria unlikely

The salient features of babesiosis are summarized in this handy graphic:

• Treatment: 1) Atovaquone and azithromycin 2) exchange transfusion for severe disease (parasitemia >10%, acute encephalopthy, acute liver failure)

• Pro Tip: Babesia can be difficult to detect by microscopy, make sure your most experienced microscopist checks many high powered fields (at least 50!) before declaring the blood smear negative