What type of vector carries disease physically without being infected itself?

• A. Mechanical vector
• B. Biological vector
• C. Active vector
• D. Silent vector

Answer: (A)

Some disease spread happens when an organism carries a pathogen on its body or in its gut without becoming infected itself. This is known as a mechanical vector. In this mode, the pathogen doesn’t invade or multiply inside the vector; it is simply transported from one place to another and deposited onto a new host, often via contaminated surfaces or food. A classic example is a housefly picking up bacteria from waste and transferring them to food. This differs from biological transmission, where the pathogen actually infects the vector and may multiply or develop within it, with transmission occurring during feeding. The terms active vector or silent vector aren’t standard descriptors of this mechanism, and a biological vector would imply infection and development of the pathogen inside the vector, which isn’t the case here.