Candida / Yeast infection is multi-caused. It can occur in small babies because their mother passed it over the placenta or in her breast milk. It can occur in the dying. The reason for dying doesn't matter a bit, it is just that the body is so weak that bacteria and fungi recognize the weakness and will take advantage of it. Between these two scenarios are all manner of personal variations, background illnesses and lifestyle factors that will encourage or allow the fungi naturally living within us to overgrow. Overgrowth causes health problems. Warmth and moisture are the primary requirements of surge conditions. Fungi also love sugar, blood and poor immune defense systems. Candida/Thrush/Yeast can also be found in all parts of the body, either localized or as part of a whole system outbreak. Treatments have to be individually assessed, but basic lifestyle factors must be well in place also.