Who proved that microorganisms can cause disease through his research?

Robert Koch proved that microorganisms can cause disease through his systematic research in the field of microbiology. He is renowned for developing Koch's postulates, which are a series of criteria used to establish a causal relationship between a microbe and a disease. His work was instrumental in identifying the specific bacteria responsible for diseases such as anthrax, tuberculosis, and cholera.

Koch's postulates allowed researchers to establish a clear framework for linking pathogens to specific diseases, which was groundbreaking in the understanding of infectious diseases. This foundational work confirmed the germ theory of disease, fundamentally changing the approach to medicine and public health.

While Louis Pasteur made significant contributions to microbiology and vaccination, particularly regarding the process of pasteurization and the creation of vaccines for rabies and anthrax, his focus was more on how to prevent diseases caused by microorganisms rather than directly establishing the causative link. Edward Jenner is credited with the development of the first smallpox vaccine, which was a monumental step but did not focus on the concept of microorganisms causing disease. Joseph Lister is known for his advances in antiseptic surgical techniques, significantly reducing infections in surgical procedures, but did not specifically prove the causative relationship between microorganisms and disease in the way that Koch did.