Abstract
Since the existence of human beings in the world, they have been haunted by various infectious diseases. In fact, the history of mankind is also a history about the human fighting against infectious diseases. Infectious diseases are characterized by acute onset, rapid spread, and high mortality rate, which have killed billions of human lives and cause endless disasters to the fortunes and cultures of human beings. For instance, many brilliant cultures, such as the ancient Roman culture, the Maya culture, the Inca culture, and the Marine Polynesian culture, were ruined by plague in a direct or indirect manner. Therefore, people have been struggling to explore the possible causes, epidemic patterns, and pathogenic mechanisms of infectious diseases. In terms of their diagnosis and treatment, from the experience stage to the experiment stage till the present molecular biology stage, more and more knowledge about infectious diseases have been gained and keep on increasing.