Since well before the COVID-19 pandemic, epidemiologists have worried about the possibility that bird flu could jump to other species, including humans. That’s why recent news reports of the virus spreading to cows in Texas and subsequently infecting more than seventy humans set off alarm bells among scientists. 

However, when pathogens jump from animals to humans, mobilizing an effective public health response is only one part of the resulting challenge. Zoonotic disease outbreaks also risk secondary social consequences that can be equally disruptive and, in many cases, similarly deadly.  

When Ebola struck North Kivu province in the Democratic Republic of the Congo in 2018, for example, the virus did more than introduce illness and death to the region. It also unleashed a wave of violence that forced local health workers to rely on militias for protection. This reliance on armed partisans in turn fueled public mistrust of health authorities, further destabilizing the region. 

Ore Koren, associate professor of political science at Indiana University Bloomington, has explored the connection between emerging zoonotic diseases and political instability with support from The Harry Frank Guggenheim Foundation. His 2024 study with coauthor Kaderi Bukari, “(Re)Emerging Disease and Conflict Risk in Africa, 1997–2019,” analyzes local-level data from 1997 to 2019 across continental Africa—including information about conflict patterns, zoonotic disease outbreaks, economic development, and climate indicators. 

“Zoonotic diseases can exert a profound influence on conflict dynamics.”

The findings, drawn from news stories that were confirmed and triangulated against policy reports and statements from the World Health Organization and the International Society for Infectious Diseases, showed that zoonotic diseases can exert a profound influence on conflict dynamics. They also showed, however, that the exact effect can vary depending on the type of conflict. For example, during zoonotic disease outbreaks, governments involved in fighting civil wars against rebels decreased their military efforts by an average reduction of as much as 120 percent, according to one statistical model. Rebel groups, by contrast, did not reduce their military activity. And conflicts prosecuted by “identity militias”—typically local groups pursuing specific agendas, like protecting grazing rights or expanding their political influence rather than government overthrow—increased their military activity by an average of 55 percent.

These outcomes arise, Koren explains, because zoonotic disease outbreaks divert state resources toward containment and treatment. Often this leads to reductions in law enforcement or military operations, creating a vacuum that nonstate forces fill. In Nigeria, for example, a massive increase in abductions by armed groups during the COVID-19 pandemic overwhelmed the state’s security forces; in many regions, vigilante militias became the de facto protectors, creating the possibility of a rise in local conflicts. In other parts of the country, where lockdowns led to a decline in official police presence, community defense forces emerged to combat rising crime. These groups often positioned themselves as protectors of their communities, but their increased power and influence weakened the state and undermined political institutions over the long term.

Given these findings, Koren recommends that state and international actors find ways to bolster government capacity so that affected jurisdictions can better handle outbreaks without neglecting other governance functions. This means, for instance, investing in robust health systems and ensuring that security forces can operate effectively even during a health crisis. 

It would be useful, too, Koren says, to design interventions that take into account the type of pathogens involved. One of his findings was that the most virulent pathogens—those that are fast-acting and deadly—do not drive declines in state activity, likely because their impact can be so swift. In such outbreaks, he says, bolstering local government capacity might not reduce conflict. Outbreaks of these pathogens may still contribute to greater frequency of violent conflicts involving identity militias, exploiting the local vulnerabilities posed by the outbreak. Therefore, broader healthcare interventions should take this risk into account as part of their design. 

More generally, Koren recommends looking beyond traditional civil wars and considering all forms of violent conflict to understand how emerging diseases might affect security. 

“The spectrum of violent actors active in conflict zones around the world is far wider than [rebels versus government],” he says. “You have a lot of groups that are not necessarily anti-government as much as they are seeking more autonomy.” By considering the full range of violence, better strategies can be developed to address the root causes and mitigate the impacts.

“Conflict and insecurity arising from disease can shape the spread of disease.”

Finally, conflict and insecurity that arise from or are intensified by a disease outbreak can, in turn, shape the spread of that disease. For example, if agricultural populations flee to forested areas to escape from armed groups seeking crops, cattle, or cash, the refugees may be exposed to zoonotic pathogens through direct contact with forest wildlife or via insect vectors. As well, in long conflicts, permanently displaced populations often settle at the edges of forests, where forest regrowth can increase transmission rates. 

In a study published in Bioscience, Koren and Luis Chavez show that conflict and economic development matter for whether land use and land cover changes may increase the risk of infectious zoonotic disease.

If zoonotic disease outbreaks become more frequent due to trends such as population growth, shifts in land use and land cover, and climate change, the need for considering their broader implications in susceptible states will become increasingly important. Koren says, “Something that I would like people to take from this research is, think of the second-order effects: If I am now stopping the government from working, if I’m now stopping security, what does it do to the average person that needs it? And what’s it going to do to the stability of this government if a nonstate militia gains power and prestige at its expense?”  

Recognizing the complex interplay between health and security can help develop more effective responses and promote more resilient societies.

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