Knowledge: Bacteria, viruses, and parasites that cause infectious diseases, known as pathogens. Where the virus is the most terrible pathogen, it belongs to parasites, different viruses will choose a different host.
"Resident Evil" series of films, is the classic virus-themed film, which T virus and G virus is a deadly biological and chemical weapons, such people developed the virus eventually spread in the world, wanton destruction of human beings. Virus, is a far more ancient than the ancient human life, has also been a fatal threat to human beings.
Studies have shown that, as early as our ancestors "Homo sapiens" period, human and virus this harmful microbiological struggle has been kicked off, in this long process, the human pay a painful price, but also step by step to expose Opened the mystery of the virus.
The virus is the only type of living body without cell structure, belonging to parasites. The choice of host cells should not be picky, but in the process of how to choose a natural host, the virus is "personality".
Although almost every individual virus is branded with a unique brand, such as "head" is very small, very simple structure, have a strong ability to change, but each family members have their own "taste." Some viruses like parasites in bacteria that are also microbial bacteria, called phages; some viruses are "vegetarians", but are intended to erode plants that are not free to move, such as tobacco mosaic virus, and are therefore known as plant viruses; some viruses It is more preference for animal cells, parasitic in animals known as animal viruses, such as smallpox virus, HIV and so on. In other words, a virus genetic code determines that it has a specific type of cell to attack and type. Plant viruses do not attack animals to make them sick. Furthermore, a plant virus can not infect all plants.
Such as the first virus known to humans - Tobacco mosaic virus (TMV). It is an RNA virus that specifically infects plants. As the host of the pathogen is very wide, it is now known that there are 198 species of plants in the 22 monocotyledonous plants. However, tobacco mosaic virus specifically infects tobacco and other solanaceae plants. Tobacco mosaic virus is mainly transmitted through the juice, can make the infected leaves look mottled fouling. Sick leaves slightly caused by micro-wound wounds, the virus can invade. After the invasion of parenchyma cells in the breeding, after entering the vascular bundle tissue infection whole plant. Tobacco locusts, tobacco insects and other chewing mouth insects can also spread TMV virus. So, even if the locusts in the tobacco field, tobacco insects carry the virus, but the tobacco mosaic virus as a plant virus does not make it infected. On the other hand, tobacco mosaic virus can be parasitized in 198 plants but can not cause disease, but only infected tobacco and other solanaceae plants.
We should be glad that there is no super virus, you can "size take-all" infected with all other life. Just as the scientific community did not develop a universal solvent, otherwise we should take what container to save it? This is not in line with the laws of nature.