What is a virus?
- A virus is a tiny germ that can make animals and plants sick. They
are too small to be seen with a microscope, an electron
needed to see them. Viruses only have DNA or RNA (genetic material) and a simple
shell. They cannot grow or divide by themselves. They
must take over a cell, and force the cell to create
copies of the virus. The cell often dies in the process.
The new viral copies then invade other cells. When enough
cells are killed, you become sick. The picture from an
electron microscope below shows multiple viruses near a
near a cell. (Source: Jon Charlesworth; Mayo Clinic).
Will penicillin prevent a viral infection?
- No! Penicillin only kills some bacteria. Bacteria are single cell organisms which
are too small to be seen without a microscope. There are
thousands of different kinds of bacteria and they are
everywhere. Most bacteria are not harmful, in fact some
are necessary for our health. However, some can make us
sick such as:
- Streptococcus pyogenes (
- Staphylococcus aureus (skin
infections and food poisoning)
- Mycobacteria tuberculosis
- Salmonella typhi (typhoid
- There are only a few drugs
currently available that have any effect at all on
viruses and they are not nearly as effective as bacterial
How many viruses are in my body compared
- To answer this question, we
turn to Leo Grady from the Laboratories for Viral
Diseases/Zoonotic Diseases, Wadsworth Center, New York
State Dept. of Health. To see his expert response, click here!