Pyrogens are substances that produce fever in the body. Substances such as bacterial products, bacterial toxins, or whole microorganisms enter the body and stimulate the host cells to produce certain mediators. What are these called?

Exogenous pyrogens

Explanation:

Are molecules that are part of the immune system and activate the immune cells and they are also responsible for the production of the bacteria in the body that stimulate the host cells to grow. And are responsible of the growth of the infections and fever.