Bacteria and Viruses
...rary, there are species of bacteria that can cause harmful and even fatal diseases. These diseases include cholera, gonorrhea, leprosy, pneumonia, syphilis, tuberculosis, typhoid fever, and whooping cough. Through breaks in the skin or natural openings, like the mouth and nose, bacteria can enter the body. Furthermore, air, food, and water can carry harmful bacteria from one person to another ceasing the body to function properly and destroying many healthy cells. Certain bacteria create toxins or poisons that cause diseases like diphtheria, scarlet fever, and tetanus. Some of the toxins are made by living bacteria, but only released after the bacterium dies. Occasionally toxins cause a form of food poisoning called botulism from bacteria in improperly canned foods. Viruses Viruses are microscopic organisms that are one of the major causes of diseases. Several viruses infect humans with diseases like measles, influenza, and the common cold. When a virus produces bacteria, cells in an organism are damaged; however, sometimes viruses live in cells without harming them. Many scientists believe that viruses are primitive because they are both living and nonliving. A virus is a lifeless particle by itself, but inside a living cell, it becomes an active organism that multiplies hundreds of times. Virus diseases in humans include AIDS, chicken pox, colds, cold sores, hepatitis, liver disease, influenza, measles, mumps, poliomyelitis, rabies, and yellow fever. The body defends itself from viruses and other harmful substances by many formulas, all of which together are called the immune system. The cure for a virus’s disease depends mainly on how you control the symptoms. Virus diseases in animals only occur in certain species. Certain viruses can cause cancer in animals. Sometimes these viruses do not destroy all of the cells that they infect. Few of the infected cells have their chemical makeup changed, which causes them to behave a...