Preventive medicine got a firm foothold in the 19th century when the causative agents of many diseases were discovered and the germ theory of disease was established.
The important discoveries in preventive medicine are:
- Anti-rabies treatment
- Cholera vaccine
- Diphtheria antitoxin
- Anti-typhoid vaccine
- Antiseptic and disinfectants
- Anti-malarial treatment
- Anti-tubercular medicine
When it was discovered that malaria was transmitted by the Anopheles mosquito, yellow fever was transmitted by the Aedes mosquito, disease prevention became easier. It became possible to control diseases by specific measures such as blocking the channels of transmission by quarantining an affected population, water purification, pasteurisation of milk, protection of food, proper disposal of sewage, destruction of insects and disinfection.