Which of the following is an example of a vector in indirect transmission?

• A. Fomite
• B. Contaminated Water
• C. Person-to-Person Contact
• D. Insect such as a Mosquito

Answer: (D)

Vectors are living organisms that spread pathogens from one host to another as part of indirect transmission. An insect such as a mosquito fits this role because it can acquire a pathogen from an infected source and transmit it to a new host, often with the pathogen multiplying inside the vector before transfer. This is different from a fomite, which is an inanimate object that can harbor microbes and pass them on when touched; contaminated water, which acts as a vehicle carrying pathogens through the environment; and direct person-to-person contact, which involves immediate transfer between individuals without an intermediary organism or object. So, an insect such as a mosquito is a classic example of a vector in indirect transmission.