Infection is caused by microorganisms that can invade our body and cause harm. These microorganisms, such as bacteria or viruses, can enter our body through various pathways, such as breathing them in, ingesting them, or even through a cut or wound. Once they enter, they begin to multiply and can cause a variety of symptoms, depending on the microorganism and the body’s response. Common symptoms of infection include fever, inflammation, redness, and swelling. Infections can be treated with antibiotics, antivirals, or other medications to help fight off the microorganisms and reduce symptoms.