Virus particles are so small that they cannot be seen by even the most powerful light microscope, and special electron microscopes have to be used. They are neither animal nor plant, but particles that are so basic that they are classified into a group of their own. They are not alive in any sense that we understand, but are overgrown molecules that are intent on reproducing themselves at the expense of any host that happens along.
Viruses particles can only exist and multiply inside the cells of the body. Because they are not truly alive, they cannot be killed, and so antibiotics that are effective against the much larger and living bacteria have no effect on viruses. Other than for a limited number of viruses that cause genital herpes, shingles, cold sores and influenza in the first 36 hours of the infection doctors have no cure for virus infections.