Pasteur developed successful vaccines against which diseases?

• A. Fowl cholera, anthrax, and rabies
• B. Smallpox
• C. Tuberculosis and cholera
• D. Malaria and dengue

Answer: (A)

Attenuation of a pathogen to train immunity is the idea this item highlights, and Pasteur’s work put it into practice for several important diseases. He showed that a weakened form of a microbe could immunize without causing the full-blown disease.

For fowl cholera, Pasteur exposed the bacteria to conditions that reduced their virulence and then used that weakened culture to vaccinate chickens. The birds developed protection and could resist later infection. This demonstrated that vaccination could be achieved by using a safer form of the organism to teach the immune system.

In anthrax, he produced an attenuated Bacillus anthracis strain and used it to inoculate animals. The vaccinated animals mounted immunity and were protected against subsequent exposure to the virulent bacteria, providing a practical model for protecting livestock and validating the vaccination approach.

For rabies, Pasteur devised a vaccine based on material from infected animals that had been treated to reduce virulence, and he successfully used it to immunize a person after exposure. This was a breakthrough in human vaccination, showing that post-exposure protection could be achieved.

These three diseases—fowl cholera, anthrax, and rabies—are historically linked to Pasteur’s vaccine work and helped establish the broader principle that vaccines can be based on weakened or inactivated pathogens. The other options reflect diseases associated with vaccines developed by others or later in history, not the set Pasteur is known for.