What are the agents called that are responsible for causing diseases?

The agents responsible for causing diseases are known as pathogens. Pathogens include a variety of microorganisms such as viruses, bacteria, fungi, and parasites that can invade the body and disrupt normal functions, leading to illness. These agents can be transmitted in numerous ways, including direct contact, contaminated food or water, and inhalation of airborne particles.

Allergens, on the other hand, are substances that trigger allergic reactions but do not cause diseases in the traditional sense; they provoke an immune response in certain individuals. Toxins refer to poisonous substances that can cause harm or disease, but they are not living organisms like pathogens. Mutagens are agents that cause changes in DNA, which can lead to mutations, potentially resulting in cancer or genetic disorders, but they are not directly classified as disease-causing agents in the same way that pathogens are. Therefore, the correct identification of pathogens underscores their central role in the study of infectious diseases and public health.