Some diseases are serious that many animals and people get sick and die. For example, bacteria (plural of bacterium) can make people sick with diarrhea, while viruses cause Mad Cow Disease and AIDS.
The bacterium and the virus are the same in many ways, but they have some big differences. The smallest bacterium is bigger than the biggest virus (ASM, 1999). The bacteria can stay alive even if it is outside the animal, but the virus cannot. Some bacteria are useful and helpful, for example lactobacilli bacteria that help people digest food, but all viruses are not helpful at all. Which of these two germs makes us sick with influenza or flu The virus. The influenza virus causes the sickness called influenza or flu.
Animals and humans can get sick with the flu. We know what happens when we have the flu: we get a fever, our body is in pain, and we cannot go to school or to work because we feel weak. Animals cannot tell us how they feel, but scientists know that animals sick with the flu feel weak because they do not move, staying in one place until they get well or die.
There is another difference between the bacteria and the virus. When the virus is inside the animal, it can change itself and become another virus, something the bacterium does not do. This change is called mutation. ...