What term describes the invasion of body tissue by disease-causing pathogens?

The term that describes the invasion of body tissue by disease-causing pathogens is "infection." An infection occurs when harmful microorganisms, such as bacteria, viruses, or fungi, enter the body, multiply, and cause illness. This process can trigger an immune response, as the body works to eliminate the invading pathogens.

The term "infestation" refers to the presence of larger parasites, such as insects or worms, living on or inside a host. While infestation can cause health issues, it is distinct from infection because it typically involves larger organisms rather than microscopic pathogens.

"Contamination" refers to the presence of unwanted substances or organisms, which can occur in various contexts but does not necessarily imply that pathogens are invading and multiplying within body tissues.

"Transmission" pertains to the process by which pathogens are spread from one host to another, whether through direct contact, airborne particles, or other means. While transmission is a crucial part of how infections begin, it does not describe the actual invasion of body tissues.

Understanding these distinctions is essential for identifying how diseases spread and affect health.