Congenital babesia is rare—but this case proves it happens. The patient was born at 36 5/7 weeks by C-section. At five-weeks-old the newborn presented to the emergency department with pallor, increased lethargy and difficulty feeding. The newborn was “more difficult to arouse and very pale compared to her twin brother,” the mother reported. “She was feeding with a similar frequency, however, with a decreased duration from 20 minutes to 10 minutes due to fatigue.”
This case of Babesia transmitted from mother to baby is the first report describing asymmetric transplacental transmission in twins—one twin infected, the other not.
The Mother’s History: Congenital Babesia Risk Factors
The mother had one febrile illness during pregnancy, “occurring at approximately 23-24 weeks of gestation, which was associated with a maculopapular rash that resolved spontaneously,” according to Walker et al.
Throughout her pregnancy, the mother had made several trips to Cape Cod, Massachusetts, an area endemic for Lyme disease and tick-borne co-infections.
Congenital Babesia: Clinical Presentation
At examination, the newborn was “febrile to 100.4°F rectally, noticeably pale, but vigorous with mild tachypnea and tachycardia into the 170s-180s beats per minute,” the authors wrote.
Blood work revealed anemia, thrombocytopenia and an elevated white count. Liver function tests were elevated, as well.
“Because of the profound hematologic abnormalities, a routine thin smear was obtained, which was significant for multiple intraerythrocytic ringed parasites consistent with Babesia microti,” the authors wrote.
Treatment for Congenital Babesia
The newborn was treated with a blood transfusion, intravenous atovaquone twice daily and azithromycin daily. Within 5 days, her Babesia parasites had cleared.
Her twin brother was negative for Babesia microti, while the mother’s test results revealed Babesia microti IgG of 1:160 and IgM of <1:10, with a negative PCR consistent with cleared infection.
Why This Case Matters
“Although case reports of congenital babesiosis exist, this is the first report describing asymmetric transplacental transmission in twins,” the authors wrote.
Furthermore, they suggest that “Tick-borne diseases, such as babesiosis, should be considered a part of the differential for anemia, thrombocytopenia, and neutropenia in a febrile infant as they are increasing in geographic range due to climate change.”
This case adds to the growing evidence that Babesia can be transmitted during pregnancy—and that not all babies exposed will become infected.
Frequently Asked Questions
Can Babesia be passed from mother to baby?
Yes. Congenital babesia transmission can occur during pregnancy, though it’s rare. This case shows it can affect one twin and not the other.
What are the symptoms of congenital Babesia?
Infected newborns may present with pallor, lethargy, difficulty feeding, fever, anemia, and thrombocytopenia—often within the first weeks of life.
How is congenital Babesia diagnosed?
A blood smear revealing parasites in red blood cells is diagnostic. PCR testing and antibody tests can confirm the infection.
How is congenital Babesia treated?
Treatment includes atovaquone and azithromycin, often with blood transfusions for severe anemia. This newborn’s parasites cleared within 5 days of treatment.
Should pregnant women be tested for Babesia?
Women who live in or travel to endemic areas and develop febrile illness during pregnancy should be evaluated for tick-borne diseases including Babesia.
References
- Walker S, Coray E, Ginsberg-Peltz J, Smith L. A Five-Week-Old Twin With Profound Anemia: A Case Report of Asymmetric Congenital Babesiosis. Cureus. Mar 2022;14(3):e22774.
How safe are blood transfusions now? (Babesia?)
Reeeeeally sad that this type of info is only coming out now, when my sons were born in 80’s & 90’s with the exact same problems! Funny how NO doctors other than infectious disease specialists would listen then. Now my grandchildren are going thru this too now. This is NOT…. new INFO…. I am 13th generation Cape Cod & tick illnesses have been here over 100 yrs… get a clue!! The gov’t & docs know.. but WE… don’t all die from these illnesses so.. no big deal right??