Human activity both social and economic is believed to play an important role in the emergence of infections. Changing eating habits can also have a great impact on the emergence of food-borne infections. In Malaysia there has been a dramatic increase in the incidence of food-poisoning. It is now common for both husband and wife in Malaysia to work. The mushrooming of street food enterprises coupled with poor enforcement of food hygiene regulations have also contributed to increasing food and water-borne infections.
Demographics also play an important role, in particular, the migration of people.
The migrants may also bring with them their cultural traditions and behaviour patterns which can influence their capacity to spread the disease to the indigenous populations. Their social standing and economic position often result in living conditions for migrants that are less than ideal. Overcrowded slums without potable water supply or sewage facilities contribute to the spread of many respiratory and gastrointestinal infections. The migrants also change the environment by clearing land for agricultural or building purposes. The climate is an important environmental factor.