Disasters are occurred when local and national systems can not respond to the needs of the population. During disasters many structural infrastructures are affected including health system. By definition it means that health systems in crises or disasters are unable to meet the basic needs of people. This may be result of the:

•- sudden increase in demand because the health facilities are overwhelmed by number of injured patients or patients who need treatment for its chronicle or new health affected conditions or

•- the institutions cannot deliver what is expected from them.

Usually, they can not deliver their regular services because they are faced with lack of stuff, hospital beds, energy or water supply and other essential resources.