An infection or infectious disease transmissible under natural conditions from vertebrate animals to human beings is a?

a small infectious agent that can replicate only inside the cells of other organisms

a single celled organism with no nucleus

any of various types of organism that get their food from decaying material or other living things

a smaller organism that lives on or in, and at the expense of, a larger organism called the host

anthrax, plague, salmonella

an infectious protein particle similar to a viruses but lacking nucleic acid

rabies, west nile virus

dematophytes (ringworm)

toxoplasmosis, toxocarasis

bovine sponiform encephalopathy (Mad Cow Disease)

The passing of a pathogen (disease-causing agent) directly to a host (animal or person) from a previous host

transmission of an infectiousagent to a host by vector or fomite

living (biting insect)

non-living (water, dust, bedding)