👉 An infection is an invasion of the body by pathogenic microorganisms, such as bacteria, viruses, fungi, or parasites, which disrupt normal biological functions and cause disease. When these microbes enter the body—through breaks in the skin, ingestion, inhalation, or other routes—they multiply and interact with host cells, often triggering an immune response. This interaction can lead to inflammation, tissue damage, and various symptoms characteristic of the infection. For example, a bacterial infection might cause fever and swelling, while a viral infection could result in fatigue and a sore throat. Understanding infections is crucial for developing treatments and preventive measures, such as antibiotics, antivirals, vaccines, and hygiene practices, to combat and reduce their impact on human health.
