Virus, the enemy public number 1 He doesn''t measure more than 30 millionths of mm. Cause influenza, measles, paralysis, variola, AIDS and etc. He/she doesn''t feed breathes, nor it produces thing some, but it is capable to multiply. For that, he/she takes advantage of the mechanisms of the cells where he/she stays, later it sacrifices them. They are known about 1000 virus species, responsible for 60% of the diseases in animals and plants. To each step, he/she is discovered the virus presence where was not suspected. One was found in the liquid are