How do pathogens typically cause illness or disease?

Pathogens typically cause illness or disease through mechanisms such as damaging host tissues and producing toxins. When a pathogen, which can be a bacterium, virus, fungi, or parasite, invades the host's body, it can disrupt normal physiological functions. This disruption is often a result of the pathogen directly harming cells, which can lead to tissue damage and the host's inability to function properly.

Additionally, many pathogens produce toxins that have harmful effects on the host. These toxins can interfere with biological processes, trigger inflammatory responses, and contribute to symptoms such as fever, pain, and other signs of illness. By combining these methods—direct damage and toxin production—pathogens are effectively able to promote disease and illness.

Understanding this mechanism is crucial, as it highlights the importance of protecting against infections through vaccines, hygiene, and other preventive measures aimed at reducing the impact of such pathogens.