There are many kind of viruses on this world, there is a viruses that attack just to animals, there is a viruses that just attack to plants, there is a viruses that is attack just to human and there are viruses that attack to both animals and human. These all depend on the viruses characteristic and depend on the virus specialized.
Virus that attack to plant also more divided into many kind of viruses, there is a virus that attack to certain plant like Orchid Virus Disease, and virus that attack to coffee or tea and viruses that just attack to tobacco. and especially viruses that attack to tobacco can be used as medicine, for more detail the description about this virus can see on this article, tobacco viruses as medicine.
From those knowledge about viruses we can conclude that there are many useful of microorganism that are exist on this world. There are many microorganism that benefit to human and even we can't alive without them and many other microorganism that danger to human and sometime can diminished of human life.
