who discovered infectious diseases are spread by microorganisms
Germ theory of disease Microorganisms are said to have been first directly observed in the 1670s by Anton van Leeuwenhoek, an early pioneer in microbiology. Yet Athanasius Kircher may have done so prior. When Rome was struck by the bubonic plague in 1656, Kircher spent days on end caring for the sick. Searching for a cure, Kircher observed microorganisms under the microscope and invented the germ theory of disease, which he outlined in his Scrutinium pestis physico-medicum (Rome 1658).[16] Building on Leeuwenhoek's work, physician Nicolas Andry argued in 1700 that microorganisms he called "worms" were responsible for smallpox and other diseases.[17]
History of syphilis The first recorded outbreak of syphilis in Europe occurred in 1494/1495 in Naples, Italy, during a French invasion.[2][3] Because it was spread by returning French troops, the disease was known as "French disease", and it was not until 1530 that the term "syphilis" was first applied by the Italian physician and poet Girolamo Fracastoro.[3] The causative organism, Treponema pallidum, was first identified by Fritz Schaudinn and Erich Hoffmann in 1905.[3] The first effective treatment,Salvarsan, was developed in 1910 by