Till the 19 th century it was believed that the outbreak of cholera was on account of putrified air ,the theory called the "miasma theory".It was believed that cholera spread by some sort of particles from person to person.It was much later the germ theory came into use to explain the origin of disease.
In India we still believe that the disease spreads on account of congestion and filth of living quarters and lack of sanitation. The people in slums and ghettos who live in horribly filthy conditions become victims to epidemics and surely the putrified air is the cause. It is only in filthy environs that the germ grows and multiplies.
Aetiology blog
