What it’s ? Where it comes from? What is the area of contamination ? There are much questions at that we can thinking. As definition , it’s a disease! The word comes from the Greek” epi”, “over the people”, it’s an infective  disease that to spread  into the limited territorial area starting with a group of people. The first  infection action is name the focus  localized into the persons’ collectivity delimited as diffusion( space, times and same origin). Without we enter in panic with every year we are confronts with a number of diseases events named epidemy. The period that presents the big risk is the winter and the spring , manifested with the flu and the breathing’s illness. The infective diseases are make of the virus or the bacteria caused of an atmospheric  change ( ecologic) , of stress and the rise species’ density ( genetic variation). The epidemiology to thinking to parasite’s people or the introduction from host people by scourge to a community with a majeure parasite density in our case is named epidemy. The human organism  enters into incapacity of the self defense versus the parasite scourge. Why?  The principal cause is lost immunity . In cold seasons, the human organism lose a series of vitamins and protein, in same kind he become weakness and vulnerable without to have a capacity of protection. Others contagions can result by contaminated  eat, infected water, migration of people or the some animals( rats, mosquitoes). In history are subscribe a series of episodes of epidemy that are transformed in times in pandemic ( typhoid Fever , antonina Pesta, bubonic Pesta, black Pesta, Typhus,  Cholera, Malaria…). For to cross of this infective period we have need of : Information, Prevention, Treatment! In all is a hope.