What is a "biological vector"?

A biological vector is defined as an organism that transmits pathogens between hosts. This typically refers to vectors like mosquitoes, ticks, and fleas, which can carry pathogens such as bacteria, viruses, or protozoa and facilitate their transmission from one host to another. For example, a mosquito can carry the malaria parasite from one person to another during a blood meal, playing a crucial role in the lifecycle of the pathogen and the spread of the disease.

The other options do not accurately describe what a biological vector is. A human carrier of diseases pertains specifically to human hosts rather than other organisms transmitting diseases. A laboratory technique for studying microbes refers to research methodologies rather than the function of biological vectors in disease transmission. Lastly, a chemical used to kill pests relates to pest control measures, not to biological organisms that host and transport pathogens. Understanding the role of biological vectors is essential in epidemiology and public health for developing strategies to mitigate the spread of infectious diseases.