Prion Diseases as Transmissible Zoonotic Diseases

Lee, Jeongmin; Kim, Su Yeon; Hwang, Kyu Jam; Ju, Young Ran; Woo, Hee-Jong

The species barrier makes it difficult for infectious diseases to be transmitted from one species to another. The value of the species barrier for prion disease transmission between humans and cattle has been estimated to be 4000, based on the study of BSE zoonosis. However, a precautionary principle assumes that there is only one value of species barrier between humans and cattle, and suggests that the same dose that causes the disease in cattle may affect humans in the same way [23] . The experimental disease-inducing amount of SRM in a single administration is 0.001 g injected orally; 10 g can lead to BSE in all administered cattle [24] . The amount required to induce the disease is very small; a scientific report submitted to the British Council in 2001 states that an amount as small as one speck of pepper may cause the disease [25] . Five grams of an oral inoculum with brain homogenate from a BSE-infected cattle in a primate (Cynomolgus macaques) resulted in the development of a vCJD-like neurological disease 60 months after exposure [26] .