Skip to main content
Biology LibreTexts

2.2: Brief descriptions of Microbial Pathogens

  • Page ID
  • Acellular pathogens: prions and viruses

    1. Prions: “proteinaceous infectious particles” (see  fig. 18.6/18.7 p 475 in Belk’s Biology)

                                    -abnormally folded cellular proteins ( abbreviated “PrP’s”=Prion Proteins)

                                    -cause Transmissible Spongiform Encephalopathies or TSE’s

                                    -100% fatal

                                    -prion diseases in animals (examples):

                                                    -scrapie/sheep, goats

                                                    -CWD, Chronic Wasting Disease / deer, elk;

                                                    -BSE, Bovine Spongiform Encephalopathy “Mad Cow Disease”/ cattle 

                                    -prion diseases in humans (examples):


                                                    -CJD, Creutzfeldt Jakob Disease

                                                -variant vCJD (from ingestion of BSE/Mad Cow prions)


    2. Viruses: “trouble wrapped in protein”  (see fig 18.4   p 472 in Belk’s Biology)

                                    -genetic info= DNA or RNA

                                    -protein coat/capsid

                                    +/- lipid envelope stolen from host cell

                                    -obligate intracellular parasites; cannot replicate unless inside host cell

                                    -e.g. smallpox/variola virus, influenza virus, herpes virus,

                                                    HIV/Human Immunodeficiency Virus, West Nile virus, Ebola virus



    Fig 1: virus examples         a=”naked”  virus     b=enveloped virus