Case #6:

Clinical Presentation:
A 35 year old man presented with a sore throat that had progressed to fever, headache, mild neck stiffness and myalgias. 15 years ago he had undergone splenectomy as part of treatment for Leukemia which was in remission at presentation. Further history taking revealed that he had recently spent an afternoon hiking in the woods of Connecticut. CSF exam showed a lymphocytic pleocytosis.

Clinical Diagnoses:
Viral Aseptic Meningitis
Bacterial Meningitis

Case 6 Images 1 and 2:
Giemsa stained peripheral blood smear showing many intra-erythrocytic ring forms with some cells demonstrating multiple ring forms.

Discussion:
Microbiologic Diagnosis:
Babesiosis
This malarial-like protozoa can be transmitted by the bite of an infected Ixodes scapularis tick. Diagnosis can be made by observation of the merozoites of Babesia microti within red blood cells. Travel history is important to the diagnosis of this infection, as the morphology of the intra-erythrocytic parasite remarkably resembles Plasmodium falciparum. Splenectomized patients are prone to more severe and apparent illness.