Which of the following statements is least descriptive of a vector?

• A. Is a carrier of pathogens from one host to another
• B. Can be an insect such as the mosquito
• C. Must be living
• D. Can be a contaminated syringe

Answer: (C)

A vector is defined as an organism or agent that carries and transmits pathogens to another organism. In the context of disease transmission, vectors are typically living organisms, often arthropods such as mosquitoes or ticks, which can harbor and transfer infectious agents.

The statement that a vector must be living is incorrect because vectors can also include non-living entities. For example, a contaminated syringe can serve as a vector for transmission of diseases like HIV or hepatitis if it has been used by an infected individual and not properly sterilized before being used by another person. This highlights that vectors are not limited to living hosts but can also include inanimate objects that facilitate the transfer of pathogens.

In summary, while many vectors are living organisms, the essential aspect of a vector is its role in transporting pathogens, and this can include non-living items as well, making the assertion that a vector must be living the least accurate.