Prophet Muhammad says:
"Cover food containers and tie water-skin because there is a certain night in which a certain disease is sent, if this disease passed by uncovered container or water-skin, it will go down in it." Narrated in Muslim's Collection of A hadeeth
It is now scientifically established that some fatal diseases are seasonal, the reason why such disease hit people in a certain time is not yet known. Cholera, hit people every seven years, Measles and infantile paralysis appears only in September and October. Typhoid hits people in summer, small box hit people every three years.
So science supports the prophet Hadeeth concerning the seasonal epidemics