Bacteria isn't the most harmful of the three but still if it is used right can make some very deadly diseases. It is made up of prokaryotic cells which simply means they don't have a nucleus and are only single celled organisms.  They are capable of multiplying very fast because they reproduce by dividing into two halves.  There are three different types of bacteria and they are defined by their shape.

• Rod Shape which is called Bacillus.
• Spherical Shape which is called Coccus. 
• Spiral or Wavy  which is called Spircohetes.

Some of the different Diseases that can be created using Bacteria are but are not limited to the following:

• Plague
• Leprosy                               
• Cholera
• Botulism
• Tetanus
• Typhoid Fever

Symptoms of a Bacterial disease often start out just like the Flu and people might not take them seriously until it would be to late.  That is why they can be so deadly because the people infected don't understand the severity of their situation.  If not dealt with properly and swiftly the disease cells will multiply very fast and take over the host.

The next form is much more deadly than the first because of its size. A virus is so small that it is able to pass through filters that Bacteria would get caught up in. The only think that makes a virus a little bit less harmless is the fact that unless its in the host it is harmless.  They also are easier to get rid of because they cannot reproduce unless in the host. Since a virus can't reproduce unless in the host it often takes a few days before people notice the virus.  Some common virus are:

• Common Cold
• Distemper in Dogs and Cats
• Rabies
• Cold Sores
• Yellow Fever
• AIDS