3. Disease
The term “disease” encompasses a broad category of illness that is typically defined in either the mode of transmission and/or the nature in which the disease progresses. For instance, the terms infectious and communicable diseases are often interchanged and refer to diseases that “can be transmitted from one human to another by physical contact or close proximity.” As the World Health Organization notes, “Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; the diseases can be spread, directly or indirectly, from one person to another. Zoonotic diseases are infectious diseases of animals that can cause disease when transmitted to humans.” Chronic diseases, such as heart disease, diabetes, arthritis and certain types of cancers, are usually more long term and progressive in nature, and they are often linked to lifestyle decisions — such as the choice to smoke or consume an unhealthy diet.
4. Displacement
Political upheaval around the world has created unprecedented rates of global forced displacement — meaning that individuals are required to leave their homes and/or homelands for any number of reasons. In fact, a 2013 United Nations High Commissioner for Refugees (UNHCR) report said that during 2012, nearly 7.6 million people became newly displaced — at a rate that equaled “a new refugee or internally displaced person every 4.1 seconds.” The World Health Organization says, “In the context of emergencies, displaced people are people who have had to leave their homes as a result of a natural, technological or deliberate event.” The resulting exodus of individuals from their homes, whether they are internally displaced within their own countries or required to cross international borders like those in the midst of the Syrian refugee crisis, means that large groups of people end up in camps where environmental health measures are inadequate and basic health care is largely unavailable.