Natural hazards (as defined earlier) such as earthquakes, hurricanes, and volcanic eruptions, among others, can have serious effects on health, but the impact varies as a function of various factors, including:

a) The severity of the hazard.

b) the vulnerability of the population.

c) The community’s state of preparedness and response capacity.

In the past, it was believed that sudden-onset disasters not only caused widespread mortality, but also produced massive social disorder, epidemics, and famines, leaving survivors totally at the mercy of international humanitarian relief. Systematic observation of the effects of natural disasters on human health has led to very different conclusions, both with respect to health effects themselves and as regards the most effective ways of providing humanitarian assistance.

Many diseases constitute serious health hazards and among these are reemerging diseases such as tuberculosis, malaria, cholera, and yellow fever, as well as emerging diseases like AIDS, severe acute respiratory syndrome (SARS), “avian flu,” and H1N1 influenza.

A list of emerging and reemerging diseases, along with information on the diseases, is available from the U. S. Institute of Allergy and Infectious Diseases.

The UNISDR definition of technological hazards refers to hazards that stem from technological or industrial conditions. This includes accidents, dangerous procedures, infrastructure deficiencies, and specific human activities that can cause death, injury, disease, or other health impacts, as well as jeopardize property, livelihood, and services, provoke social or economic disorder, and cause environmental damage.

Social hazards, also called complex emergencies, seriously limit a population’s access to health services, water, food, and transportation, all of which are determinants of health. They also often lead to a lack of safety and tend to come hand in hand with natural disasters such as floods.

Whether for economic reasons or as a result of internal conflict, displaced populations face serious challenges when it comes buy cenforce online to health care. In Colombia, for example, approximately 80-90 percent of the large internally displaced population has insurance coverage, yet the percentage with effective access to health services is very low—not more than 40%. Barriers such as geographical dispersion, the presence of illegal armed forces, administrative and operational problems, and weak health institutions, all negatively affect the timely provision and quality of service.