A Five-Week-Old Twin With Profound Anemia: A Case Report of Asymmetric Congenital Babesiosis.

We present a case report and review of the literature of congenital transmission of babesiosis in a five-week-old twin neonate evaluated for lethargy and difficulty with feeding. On presentation to the pediatric emergency department, the patient appeared pale and was found to be profoundly anemic with intraerythrocytic ringed parasites consistent with Babesia microti visible on a thin smear. The patient received a blood transfusion and was treated with a regimen of atovaquone and azithromycin with full recovery. The other twin remained asymptomatic with negative Babesia polymerase chain reaction testing.