Forced Migration


Forced migration has occurred from the earliest periods of human history as a result not only of conflict (war or ethnic or religious persecution) but also as an outcome of other disasters. The International Association for the Study of Forced Migration (IASFM) at Georgetown University defines it as “a general term that refers to the movements of refugees and internally displaced people (those displaced by conflicts) as well as people displaced by natural or environmental disasters, chemical or nuclear disasters, famine, or development projects.”

In this picture taken on Friday, Oct. 7, 2016, Syrian citizens attend a sit-in against the forced displacement in Syria, in front the United Nations headquarters, in downtown Beirut, Lebanon.

In this picture taken on Friday, Oct. 7, 2016, Syrian citizens attend a sit-in against the forced displacement in Syria, in front the United Nations headquarters, in downtown Beirut, Lebanon. The Arabic placards on the ground read: “The forced displacement sponsored by the United Nations, Russia is partner with Assad in the forced displacement, I'll steadfast on my ground, No for the demographics change in Syria.”
(AP Photo/Hussein Malla)

Some examples of disease emergence and reemergence among displaced persons and refugees from conflict include the following:


Forced migration during earlier periods of human history typically resulted from violence (war or civil war) that caused people to flee for their lives. Sometimes countries made war in order to capture people for slave labor or to sell them to other countries as slaves; the medieval Viking raids on what is now England were done for this reason, as were the Aztecs' wars on their neighbors in Central America prior to the coming of the Spanish. People might also leave their homelands because of famine, disease, or other natural disasters beyond their control, as happened to the Irish during the potato famine of the 1840s and 1850s. Forced migration did not, however, become a subject of study and analysis until after World War II, when the establishment of the United Nations provided an international organization and a legal framework for dealing with forced migration. In addition, social scientists began to realize that the relative ease and speed of modern transportation vastly increased the numbers of migrants, and that forced migration anywhere in the world could affect countries far removed from the scene of conflict or disaster.

Examples of different types of forced migration in the twentieth and twenty-first centuries are as follows:

Referring to a disease that is maintained in a population without the need for external inputs. The infection neither dies out nor increases exponentially.
Internally displaced persons (IDPs)—
A term used to describe people who are forced to flee their homes but remain within their country's borders. IDPs are often referred to as refugees although they do not fit the legal definition of a refugee. The UN defines a refugee as “an individual who is outside his or her country of nationality or habitual residence who is unable or unwilling to return due to a well-founded fear of persecution based on his or her race, religion, nationality, political opinion, or membership in a particular social group.”
Neglected tropical disease (NTD)—
Any of a group of infectious diseases that are common among low-income populations in developing countries in Asia, Africa, and Central and South America. Leishmaniasis is classified as a neglected tropical disease and assigned high priority by the World Health Organization.
Notifiable disease—
Any disease that is required by law to be reported to government public health authorities.
The period of time during which a person, animal, or shipment of goods that might have an infectious disease is confined or isolated to keep the disease from spreading. The English term comes from the Italian words for forty days, the time period mandated in the fourteenth century to prevent the Black Death from entering Italian ports.


The population of Syria was estimated to be around 23 million in 2011 before the outbreak of civil war. This figure included the 1.5 million refugees from Iraq. The population fell to 17.9 million by 2014, according to the CIA World Factbook, a drop that resulted from an increased number of deaths due to war and disease, and to 5.5 million Syrians fleeing abroad. According to the U.N. High Commissioner for Refugees (UNHCR), Syria was the single greatest source of forced migration in the world as of 2017, its 5.5 million migrants constituting a larger group than the migrants from the next two countries combined, Afghanistan (2.5 million) and South Sudan (1.4 million).

Although most migrants from Syria moved to Turkey, Lebanon, or Jordan when civil war first broke out, after 2015 growing numbers of them sought asylum in Europe. Updated figures from UNHCR indicate that 952,446 Syrians applied for asylum in Europe between 2011 and May 2017, 138,000 in 2014 alone. Two-thirds of the refugees sought asylum in Germany and Sweden; 21% in the Netherlands, Denmark, Hungary, Austria, or Bulgaria; and the remainder in other European countries. Another 7 million Syrians are thought to be IDPs.

Other notable demographic statistics include the fact that the birth rate in Syria dropped from 500,000 births per year in 2011 to 200,000 per year by 2015. In addition, the life expectancy fell from 75.9 years prior to the civil war to 55.7 years in 2016. About 80% of the population remaining in Syria was living in poverty, as the unemployment rate rose from 14% in 2011 to 58% at the end of 2014. The UN estimated that the number of deaths resulting from the conflict was as high as 270,000, a figure higher than the number of people who died from the atomic bombs dropped on Hiroshima and Nagasaki in 1945.

Public health role and response

The role of public health authorities in any country receiving forced migrants is complex. One task is verifying the migrant's country of origin in order to keep surveillance statistics on any disease the migrant might have, and determine his or her admissibility to the destination country.

A second task is to screen migrants for communicable and chronic diseases, and, in some countries, mental health issues. The CDC's instruction for physicians states explicitly, “Applicants are inadmissible into the United States if they are determined 1) to have a communicable disease of public health significance; 2) to have a physical or mental disorder and behavior associated with the disorder that may pose, or has posed, a threat to the property, safety, or welfare of the applicant or others; 3) to have a history of a physical or mental disorder associated with behavior which posed a threat to the property, safety, or welfare of the applicant or others and which is likely to recur or lead to other harmful behavior; or 4) to be a drug abuser or addict.” These health examinations may be performed overseas before the applicant travels to the United States.

Legal and regulatory issues

In the United States, the Secretary of the Department of Health and Human Services (HHS) is empowered by the Immigration and Nationality Act (INA) and the Public Health Service Act to establish requirements for the medical examination of aliens seeking admission to the United States. The CDC's Division of Global Migration and Quarantine (DGMQ) issues medical screening guidelines for all physicians performing health examinations, whether overseas or in the United States. These guidelines describe the scope of the examination in detail.

A major change that has taken place since the influenza pandemic of 2009 is the CDC's requirement that applicants for entry be screened for quarantinable communicable diseases. As of 2017, the list included cholera, yellow fever, plague, viral hemorrhagic fevers, diphtheria, infectious TB, smallpox, severe acute respiratory syndromes, and “influenza caused by novel or reemergent influenza viruses that are causing, or have the potential to cause, a pandemic.” The reason for the changes was to give the CDC and the examining physicians greater flexibility to respond quickly to rapidly emerging new diseases or reemerging older ones in specific populations, including migrants from specific countries.

Future outlook

It is unlikely that the general problems of conflict and forced migration will end as long as there is a scarcity of any kind of resource, whether land, food, health care, or political power, and as long as human beings are prepared to fight to obtain what they need or to keep what they have. Although various attempts had been made to resolve the civil war in Syria, including United Nations–sponsored peace talks in Geneva in 2016, as of 2017 it appeared that the conflict was likely to continue for the foreseeable future.

See also Antimicrobial resistance ; Cholera ; Globalization and emerging diseases ; Leishmaniasis; Pandemic .



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American Society of Tropical Medicine and Hygiene (ASTMH), One Parkview Plaza, Ste. 800, Oakbrook Terrace, IL, 60181, (847) 686-2238, Fax: (847) 686-2251,, .

Centers for Disease Control and Prevention, Division of Global Migration and Quarantine (DGMQ), 1600 Clifton Road, Atlanta, GA, 30329, (800) CDCINFO (232-4636), , .

Infectious Diseases Society of America (IDSA), 1300 Wilson Blvd., Ste. 300, Arlington, VA, 22209, (703) 299-0200, Fax: (703) 299-0204, , .

International Association for the Study of Forced Migration (IASFM), Georgetown University, 3300 Whitehaven St. NW, Ste. 3100, Washington, DC, 20007, (202) 687-2258, Fax: (202) 687-2541,, .

International Organization for Migration, 17 Route des Morillons, P.O. Box 17, Geneva CH-1211, Switzerland, 19, 41 22 717 9111, Fax: 41 22 798 6150,, .

World Health Organization (WHO), Avenue Appia 20, Geneva CH-1211, Switzerland, 27, , .

Rebecca J. Frey, PhD

  This information is not a tool for self-diagnosis or a substitute for professional care.