ABSTRACT
Infectious diseases were long thought to be the work of evil deeds of individuals or communities. Although the discovery of microbes was made by Louise Pasteur in 1860s, when he disproved the spontaneous generation theory, it was not until 1870s, when Robert Koch linked microbes as the causative agents of disease. He postulated a set of criteria which provided a foundation for the study of medical microbiology, now known as 'Koch's postulates'.
