The 2013–2016 West Africa Ebola virus disease pandemic was the largest, longest, deadliest, and most geographically expansive outbreak in the 40-year interval since Ebola was first identified. Fear-related behaviors played an important role in shaping the outbreak. Fear-related behaviors are defined as “individual or collective behaviors and actions initiated in response to fear reactions that are triggered by a perceived threat or actual exposure to a potentially traumatizing event. FRBs modify the future risk of harm.” This review examines how fear-related behaviors were implicated in (1) accelerating the spread of Ebola, (2) impeding the utilization of life-saving Ebola treatment, (3) curtailing the availability of medical services for treatable conditions, (4) increasing the risks for new-onset psychological distress and psychiatric disorders, and (5) amplifying the downstream cascades of social problems. Fear-related behaviors are identified for each of these outcomes. Particularly notable are behaviors such as treating Ebola patients in home or private clinic settings, the “laying of hands” on Ebola-infected individuals to perform faith-based healing, observing hands-on funeral and burial customs, foregoing available life-saving treatment, and stigmatizing Ebola survivors and health professionals. Future directions include modeling the onset, operation, and perpetuation of fear-related behaviors and devising strategies to redirect behavioral responses to mass threats in a manner that reduces risks and promotes resilience.

The 2013-2016 West Africa Ebola virus disease epidemic was notable for its scope, scale, and complexity. This briefing presents a series of distinguishing epidemiological features that set this outbreak apart.Compared to one concurrent and 23 previous outbreaks of the disease over 40 years, this was the only occurrence of Ebola virus disease involving multiple nations and qualifying as a pandemic. Across multiple measures of magnitude, the 2013-2016 outbreak was accurately described using superlatives: largest and deadliest in terms of numbers of cases and fatalities; longest in duration; and most widely dispersed geographically, with outbreak-associated cases occurring in 10 nations.In contrast, the case-fatality rate was much lower for the 2013-2016 outbreak compared to the other 24 outbreaks. A population of particular interest for ongoing monitoring and public health surveillance is comprised of more than 17,000 "survivors," Ebola patients who successfully recovered from their illness.The daunting challenges posed by this outbreak were met by an intensive international public health response. The near-exponential rate of increase of incident Ebola cases during mid-2014 was successfully slowed, reversed, and finally halted through the application of multiple disease containment and intervention strategies.

As illustrated powerfully by the 2013–2016 Ebola outbreak in western Africa, infectious diseases create fear and psychological reactions. Frequently, fear transforms into action – or inaction – and manifests as “fear-related behaviors” capable of amplifying the spread of disease, impeding lifesaving medical care for Ebola-infected persons and patients with other serious medical conditions, increasing psychological distress and disorder, and exacerbating social problems. And as the case of the US micro-outbreak shows, fear of an infectious-disease threat can spread explosively even when an epidemic has little chance of materializing. Authorities must take these realities into account if they hope to reduce the deadly effects of fear during future outbreaks.

This Briefing focuses on the work of an expanding team of researchers that is exploring the dynamics of fear-related behaviors in situations of mass threat.. Disaster case scenarios are presented to illustrate how fear-related behaviors operate when a potentially traumatic event threatens or endangers the physical and/or psychological health, wellbeing, and integrity of a population. Fear-related behaviors may exacerbate harm, leading to severe and sometimes deadly consequences as exemplified by the Ebola pandemic in West Africa. Alternatively, fear-related behaviors may be channeled in a constructive and life-saving manner to motivate protective behaviors that mitigate or prevent harm, depending upon the nature of the threat scenario that is confronting the population. The interaction between fear-related behaviors and a mass threat is related to the type, magnitude, and consequences of the population encounter with the threat or hazard. The expression of FRBs, ranging from risk exacerbation to risk reduction, is also influenced by such properties of the threat as predictability, familiarity, controllability, preventability, and intentionality.

Climate change is increasingly forcing population displacement, better described by the phrase environmentally induced forced migration. Rising global temperatures, rising sea levels, increasing frequency and severity of natural disasters, and progressive depletion of life-sustaining resources are among the drivers that stimulate population mobility. Projections forecast that current trends will rapidly accelerate. This will lead to an estimated 200 million climate migrants by the year 2050 and create dangerous tipping points for public health and security.Among the public health consequences of climate change, environmentally induced forced migration is one of the harshest and most harmful outcomes, always involving a multiplicity of profound resource and social losses and frequently exposing migrants to trauma and violence. Therefore, one particular aspect of forced migration, the effects of population displacement on mental health and psychosocial functioning, deserves dedicated focus. Multiple case examples are provided to elucidate this theme. (Disaster Med Public Health Preparedness. 2018;page 1 of 7).