Spiroplasma sp. 16S rDNA in Creutzfeldt-Jakob disease and scrapie as shown by PCR and DNA sequence analysis.

The pathogenesis of the transmissible spongiform encephalopathies (TSE), which include Creutzfeldt-Jakob disease (CJD) in humans and scrapie in sheep, remains an enigma. In this paper we present evidence for the association of Spiroplasma sp., a wall-less prokaryote, with TSE. We have shown PCR amplification of Spiroplasma 16S rDNA in TSE-infected brain tissues (13 of 13 CJD cases and 5 of 9 scrapie cases) and not in control brains (0 of 50). Direct sequencing of the amplified PCR products has confirmed the presence of Spiroplasma-like DNA in all 5 of the TSE brains tested. Our evidence is not necessarily in conflict with involvement of a PrPres--a protease-resistant host-derived protein referred to as the prion--in the pathogenesis of TSE, since there is evidence that another factor is involved. We propose a bacterium, namely Spiroplasma, as this associated factor although the role of Spiroplasma in TSE cannot be determined from these experiments. The presence of the nucleic acid sequence of this microbe in all cases of TSE in our laboratory and not in controls provides direct evidence of the association of Spiroplasma sp. with TSE.