Assistant Laboratory Animal Technician (ALAT) Practice Exam

The correct answer is vector, as it specifically refers to an organism that can carry and transmit disease-causing microorganisms, such as bacteria or viruses, from one host to another. Vectors are typically living organisms, commonly arthropods like mosquitoes, ticks, and fleas, which play a crucial role in the life cycle of pathogens. For example, mosquitoes can transmit malaria and dengue fever, underscoring the importance of understanding vectors in the context of disease transmission.

Other choices describe different concepts. A pathogen is a microorganism that can cause disease, but it doesn’t refer to the organism that transmits it. A fomite is a non-living object that can carry infectious agents, like contaminated surfaces or utensils, and a carrier refers to an individual, often asymptomatic, who harbors a pathogen and can spread it to others. Thus, while all these terms are related to disease transmission, only 'vector' specifically identifies the organism that actively participates in the transfer process between hosts.