“…17 The hypothesis contends that the following additional variables must exist in addition to the ones listed above in order for an epidemic to manifest and spread: patients in incubation, patients throughout the clinical course and atypical course of the disease, carriers (healthy and convalescent), and exposure to infection (exposure); the source of infection (it can only be a live thing, human or animal); ways that illness is propagated and transmitted: by touch (contact): direct and indirect, through contaminated food, water, air, soil, and insects; entry point of the causative agent into the host's organism: respiratory system, digestive system and injured or uninjured skin and visible mucous membrane; sufficient quantity (dose) and virulence of pathogenic germs (microorganisms or their products): bacteria, viruses, rickettsia, protozoa and fungi -their quantity and strength are important; disposition or immunity of the host organism (propensity of the organism to get sick from some infectious disease due to lack of hereditary or acquired immunity) depends on: age, sex, race, climatic and meteorological factors, physical and psychological trauma, diet, housing. 18 Epidemics, ie diseases, and the viruses that cause them do so through a biological process. Namely, this process is in fact one constant chain that has two basic forms, those forms are in fact the dynamics of the spread of the disease, that is, the epidemic: the first form is stormy, explosive, and the second is gradual.…”