In another study of Aguilar-Calvo, goats with the 222K prion protein (PrP) codon appeared relatively highly resistant to oral infection with experimentally derived goat BSE. While wild type goats or 211Q/R goats showed positivity inside brain tissue by immunohistochemistry (microscopy), the 222Q/K goats remained negative. Also when tested for infectivity using the highly BSE-sensitive mouse line Tg110, the wild type and 211Q/R animals became before 37 months after infection clinically ill and appeared PrPSc positive in brain and peripheral tissues. However, very low infectivity was detected in the brain from only one of the two 222Q/K goats euthanized at 44-45mpi; the animals appeared still healthy. Also, only sub-base line traces of infectivity were detected in the eye muscles from both goats, thus suggesting that 222K PRNP variant drastically decreases the susceptibility of goats to goat derived BSE. These results demonstrate that transmission of goat-BSE is genotype dependent and highlight the pivotal protective effect of the 222K PRNP variant in the oral susceptibility of goats to BSE.