Detection of Chronic Wasting Disease prions in fetal tissuesoffree-ranging white-tailed deer

The transmission of chronic wasting disease (CWD) has largely been attributed to contact with infectious prions shed in excretions (saliva, urine, feces, blood) by direct animal-to-animal exposure or indirect contact with the environment. Less-well studied has been the role mother-to-offspring transmission may play in the facile transmission of CWD. We asked whether such extensive spread may also be due to mother-to-offspring transmission, perhaps before birth. We thereby focused on a population of white-tailed deer from West Virginia, USA, in which CWD has been detected. Fetal tissues, ranging from 113 to 158 days of gestation, were harvested from the uteri of CWD+ dams in the asymptomatic phase of infection. Using serial protein misfolding amplification (sPMCA), we detected evidence of prion seeds in 6 of 14 in utero harvested fetuses, with earliest detection at 113 gestational days. This is the first report of CWD detection in free ranging white-tailed deer fetal tissues. Further investigation within cervid populations across North America will help define the role and impact of mother-to-offspring vertical transmission of CWD.