Evidence of in utero transmission of classical scrapie in sheep

Abstract

Classical scrapie is one of the transmissible spongiform encephalopathies (TSEs), a group of fatal infectious diseases that affect the central nervous system (CNS). Classical scrapie can transmit laterally from ewe to lamb perinatally or between adult animals. Here we report detection of infectivity in tissues of an unborn fetus, providing evidence that in utero transmission of classical scrapie is also possible.

FIG 1

(A) Dorsal motor nucleus of the vagus nerve from ewe PG1657/05 showing widespread PrP^Sc deposits. (B) Placentome from fetus PG1658/05 at the 4th month of pregnancy showing restricted PrP^Sc deposits. (C) Greater magnification of the PrP^Sc-positive area shown in panel B to demonstrate that both maternal and fetal opposing units are affected and to illustrate the different PrP^Sc deposition patterns between maternal and fetal units. These different PrP^Sc deposition patterns most likely reflect the different physiological roles of maternal and fetal units, as both units were of the same PrP genotype. (D) For comparison, a placentome collected near term demonstrates the widespread PrP^Sc dissemination at the end of the 5th month of gestation. All sections were labeled with the monoclonal antibody R145. The maternal unit is denoted by the letter M, the fetal unit by the letter F. The scale bars in panels A and C represent 50 μm, in panels B and D, 200 μm.