Babesia Congenital Transmission and Newborn Risks

Babesia can be transmitted by ticks and rarely during pregnancy
Congenital transmission may cause serious illness in newborns
Anemia and thrombocytopenia can be important clues

Babesia congenital transmission is rare, but this case highlights why Babesia should be considered in newborns with fever, anemia, thrombocytopenia, and possible maternal exposure in endemic areas.

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 mother reported the baby was “more difficult to arouse and very pale compared to her twin brother.” She was feeding with similar frequency but for shorter periods because of fatigue.

What is Babesia?

Babesia is a parasite that infects red blood cells. Babesiosis is most often transmitted through the bite of an infected tick, but transmission can also occur through blood transfusion and, rarely, from mother to baby during pregnancy.

Because Babesia infects red blood cells, patients may develop anemia, fatigue, fever, and abnormal blood counts.

How is Babesia transmitted?

Babesia is primarily transmitted through tick bites, but infection may also occur through blood transfusion or, rarely, congenital transmission during pregnancy.

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 and colleagues.

Throughout pregnancy, the mother made several trips to Cape Cod, Massachusetts, an area endemic for tick-borne diseases.

In this case, the authors described congenital transmission because the newborn developed Babesia infection shortly after birth while her twin brother tested negative.

Congenital transmission meaning

Congenital transmission means an infection is passed from mother to baby during pregnancy or around the time of birth.

In simple terms, congenital transmission means an infection passes from mother to baby before birth or during delivery. Babesia congenital transmission appears uncommon but may lead to serious illness in newborns.

In this case, the authors wrote, “Although case reports of congenital babesiosis exist, this is the first report describing asymmetric transplacental transmission in twins.”

Babesia symptoms in a newborn

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, an elevated white count, and elevated liver function tests.

“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.

Babesia treatment in this newborn

The newborn was treated with a blood transfusion, intravenous atovaquone twice daily, and azithromycin daily.

Within five days, her Babesia parasites had cleared.

Her twin brother tested negative for Babesia microti. The mother’s test results showed Babesia microti IgG of 1:160 and IgM of <1:10, with a negative PCR consistent with cleared infection.

Why congenital Babesia matters clinically

This case shows why tick-borne diseases may need to be considered in febrile infants with unexplained anemia, thrombocytopenia, or abnormal blood counts.

The authors 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.”

Learn more about Babesia and tick-borne coinfections.

Frequently Asked Questions

What is Babesia?

Babesia is a parasite that infects red blood cells and can cause babesiosis, a tick-borne infection.

How is Babesia transmitted?

Babesia is usually transmitted through infected ticks, but it can also be transmitted through blood transfusion and rarely from mother to baby during pregnancy.

What does congenital transmission mean?

Congenital transmission means an infection is passed from mother to baby during pregnancy or around birth.

How is a congenital infection contracted?

Congenital infections occur when infectious organisms pass from mother to baby during pregnancy, delivery, or shortly after birth.

What are Babesia symptoms in newborns?

Babesia symptoms in newborns may include fever, pallor, lethargy, difficulty feeding, anemia, thrombocytopenia, and abnormal liver tests.

How is Babesia treated?

Babesia treatment may include atovaquone and azithromycin, and severe cases may require additional supportive care such as blood transfusion.

Clinical Takeaway

Congenital Babesia transmission is rare, but newborns with fever, pallor, anemia, thrombocytopenia, and maternal exposure in endemic areas may require evaluation for babesiosis.

Babesia should remain in the differential diagnosis when a febrile infant has unexplained hematologic abnormalities.

Related Articles

Babesia
The case of an untreated Babesia infection
Wide range of Babesia symptoms and presentations
Tick-borne coinfections

References

1. 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. 2022;14(3):e22774.

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Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention