What is the differences between microbe, bacteria and virus?
The most common types are bacteria, viruses and fungi. There are also microbes called protozoa. These are tiny living things that are responsible for diseases such as toxoplasmosis and malaria.
Well-known examples of bacteria include salmonella and staphylococcus bacteria.
Fortunately, most bacteria are harmless. In fact, many bacteria are beneficial and help with metabolism and other aspects of human health. Many of them even live on or in our body and help us to stay healthy. For instance, lactic acid bacteria in the bowel help us to digest food. Other bacteria help the immune system by fighting germs. Some bacteria are also needed in order to produce certain types of food, like yogurt, sauerkraut or cheese.
But some bacteria definitely do cause disease. Once harmful—or “pathogenic”—bacteria enter your body, there are a variety of ways they can cause illness. Some species of bacteria cause infection of open wounds, others proliferate in your kidneys causing urinary tract infections. Other species affect the spinal cord, causing bacterial meningitis. Still others only grow in fluid inside the lungs, leading to bacterial pneumonia.
Viruses invade healthy cells and start to multiply from these cells. A virus can't reproduce without these host cells.
Many viruses are responsible for diseases. Some are harmless and only trigger a minor cold, while others can cause serious diseases like AIDS. Other diseases caused by viruses include influenza ("the flu"), measles or inflammation of the liver (viral hepatitis).
It's relatively difficult to fight viruses with medication. To protect against some viruses, the immune system can be “trained” by a vaccination so that the body is better prepared to fight the virus.