If You Wanted to Show That an Infectious Agent Is

Question

If you wanted to show that an infectious agent is a virus, what experiment could you do?
A) Show that the agent can be seen under a light microscope.
B) Show that agent contains a lipid membrane.
C) Show that the agent can form single colonies on an agar plate.
D) Show that the agent can be diluted and can still cause disease in an animal.
E) Show that the agent can pass through a porcelain filter and is still infectious.

Accepted Answer

Viruses are much smaller than bacteria and other pathogens, so they can pass through filters that trap larger organisms. The ability of an agent to remain infectious after passing through a porcelain filter, which would trap bacteria and larger particles, indicates that the agent is likely a virus. This method was historically used in the discovery of viruses.