What is the term for the invasion and multiplication of microorganisms in body tissues?

The term for the invasion and multiplication of microorganisms in body tissues is infection. An infection occurs when harmful microorganisms, such as bacteria, viruses, or fungi, enter the body, begin to grow, and cause disease. This can lead to the body’s immune response attempting to combat the invading pathogens, which may manifest as various symptoms depending on the type and severity of the infection.

Inflammation refers to the body's response to injury or infection, characterized by redness, heat, swelling, and pain, but it does not specifically denote the presence of microorganisms within tissues. Contamination indicates the presence of unwanted substances, including pathogens, but it does not imply that those pathogens are multiplying in the body. A pathogen outbreak typically signifies a situation where there is a sudden increase in the incidence of a disease caused by a specific pathogen, rather than the individual interaction of microorganisms with body tissues.

Understanding the distinction between these terms is crucial in the context of health and emergency response, particularly in identifying and addressing infections effectively.