*[[Parasites]]- comprising [[protozoa]] and [[helminths]]
*[[Parasites]]- comprising [[protozoa]] and [[helminths]]
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A fifth controversial type are Pirons, which are infectious proteins that are believed to be the cause of bovine spongiform encephalopathy (BSE) and the human variant Creutzfeldt–Jakob disease (vCJD).<br />
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All exist as either:
All exist as either:
*Primary pathogens ('''obligate'''): presence always corresponds with disease
*Primary pathogens ('''obligate'''): presence always corresponds with disease