👉 Infectious disease, often referred to as infection, is a condition caused by the invasion and multiplication of pathogenic microorganisms—such as bacteria, viruses, fungi, or parasites—within a host organism. These pathogens can enter the body through various routes, including respiratory droplets, contaminated food or water, vectors like mosquitoes, or direct contact. Once inside, they disrupt normal cellular functions, leading to symptoms ranging from mild irritation to severe illness and death. The body's immune system typically responds by mounting an attack to eliminate the invader, but in some cases, the infection can persist or become chronic if the pathogen evades or suppresses the immune response. Understanding the mechanisms of infection is crucial for developing effective treatments, vaccines, and preventive measures to control and prevent the spread of infectious diseases.
