This was published about a year ago, but I just ran across it on another website. I think this definitely goes to proof that babesia can be chronic. The mother was supposedly asymptomatic and had a titer of 1:256 when tested which is not really that high. And her blood smears were negative which also demonstrates that multiple testing methods are needed to rule out babesia.
Vertical transmission of Babesia microti, United States.
Joseph JT1, Purtill K, Wong SJ, Munoz J, Teal A, Madison-Antenucci S, Horowitz HW, Aguero-Rosenfeld ME, Moore JM, Abramowsky C, Wormser GP.
Abstract
Babesiosis is usually acquired from a tick bite or through a blood transfusion. We report a case of babesiosis in an infant for whom vertical transmission was suggested by evidence of Babesia spp. antibodies in the heel-stick blood sample and confirmed by detection of Babesia spp. DNA in placenta tissue.