Pathogens are organisms that cause diseases. They can be bacteria, viruses, fungi, or parasites that invade the body and disrupt its normal functioning, leading to illness. These microorganisms have the ability to multiply and spread within the body, causing various symptoms and health problems. Pathogens can be transmitted through direct contact, contaminated food or water, or through the air. Understanding and identifying pathogens is crucial in preventing and treating diseases, as it helps in developing appropriate strategies to control their spread and protect public health.