Level 4 viruses are more numerous and are represented by species such as Ebola virus, Machupo virus, Lassa virus, Crimean-Congo hemorrhagic fever virus and others. In virology, viruses can be classified into four levels according to the degree of danger, and “level 4 viruses” refers to the highest level of safety isolation when isolating or experimenting with microbial tissues in the laboratory. These viruses are mostly incurable and are represented by the Ebola virus, Machupo virus, Lassa virus, Crimean-Congo hemorrhagic fever virus, and others. Viruses are specialized organisms with no cellular structure, which cannot survive on their own but must live in the cells of other organisms, and which can utilize the host cell system to replicate and thus cause disease in the human body.