Any organism is lucky to live in this house. It gets a comfortable rent, heat, hot water, lots of good food and medicine and a friendly chemical environment, all paid for by the host body. The comfortable living could, however, change at the parasites home. Change occurs because the host body changes its regime for reasons such as illness, different food and drink habits, medicines, physical, emotional or mental stress or the chemicals it lives around, breathes in or ingests. The microorganism is apt then to change its species, requirements, body habitat site, number of family members and living habits.
Parasites can be beneficial and harmless and for the most part that's the way things are.
If the parasites start to change their habits, adapt and proliferate, the human immune system will pursue them, control them, keep them in a non threatening position. If the immune system fails to do its job of cleaning up the mess Candida makes, the yeast will start playing havoc on the body it inhabits. Some things we do, eat or lack supports the onslaught of Candida. The Twentieth Century life style encourages the development of a human body that is friendly to Candida. It is a life style that is full of stress, follows a diet of processed, fried and sweet foods and dependence on medicines such as antibiotics, steroids and oral contraceptive pulls.