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When Jenner introduced vaccination he knew nothing of the infectious agents that cause disease: it was not until late in the 19th century that Robert Kock proved that infectious diseases are caused by microorganisms, each one responsible for a particular disease, or pathology.  We now recognize four broad categories of disease-causing [[microorganism]]s, or [[pathogen]]s: these are [[virus]]es; [[bacteria]]; pathogenic [[fungi]]; and other relatively large and complex eukaryotic organisms collectively termed [[parasite]]s.

When Jenner introduced vaccination he knew nothing of the infectious agents that cause disease: it was not until late in the 19th century that Robert Kock proved that infectious diseases are caused by microorganisms, each one responsible for a particular disease, or pathology.  We now recognize four broad categories of disease-causing [[microorganism]]s, or [[pathogen]]s: these are [[virus]]es; [[bacteria]]; pathogenic [[fungi]]; and other relatively large and complex eukaryotic organisms collectively termed [[parasite]]s.

The discoveries of Koch and other great 19th century microbiologists stimulated the extension of Jenner's strategy of vaccination to other diseases.

The discoveries of Koch and other great 19th century microbiologists stimulated the extension of Jenner's strategy of vaccination to other diseases.  In the 1880's, [[Louis Pasteur]] devised a vaccine against cholera in chickens, and developed a rabies vaccine that proved a success upon its first trial use in a boy bitten by a rabid dog.

==See Also==

==See Also==