One Health

How political, cultural, and economic forces can shape the risk of zoonotic disease

Heather Carroll — Mon, 05 Oct 2026 18:37:43 +0000

How political, cultural, and economic forces can shape the risk of zoonotic disease Heather Carroll Mon, 10/05/2026 - 14:37

In eastern Ethiopia, pressures like conflict and displacement are changing how people and their camels travel, shifting livestock into new environments and potentially influencing the risk of zoonotic diseases spreading between animals and humans.

Amira Roess, PhD, MPH. Photo provided

A new study co-led by 911�� infectious disease expert Amira Roess explores these connections as part of a broader look at how politics, culture, economics, and international trade factor into zoonotic disease risk in livestock-herding communities. Published in Social Science & Medicine, the research is part of a long-running international collaboration funded in part by a $2.5 million National Science Foundation grant, for which Roess is principal investigator.

For this paper, researchers interviewed more than 100 people involved in camel herding, care, milking, trading, and slaughter across eastern Ethiopia. They identified several factors that could affect zoonotic disease risk:

People and camels often live in close proximity, and grazing camels can come into contact with other wildlife.
Raw camel milk is widely consumed fresh and unpasteurized.
Conflict and displacement can push people and livestock onto new routes and into wildlife preserves, changing where they encounter other animals.
Trade restrictions and challenges accessing export facilities can push more activity into informal markets outside of disease surveillance systems.

Because diseases that spread between animals and humans account for most emerging infectious diseases, the researchers emphasize the importance of a “One Health” approach, which considers human, animal, and environmental health together.

“When we think about diseases moving between animals and people, we tend to focus on the pathogen or the animal carrying it. This study shows why we also need to understand the broader and more complex circumstances that affect how people and animals interact,” said Roess, professor of global health and epidemiology in the Department of Global and Community Health at the College of Public Health.

Read the full study here.

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Key Takeaways

Conflict, displacement, cultural practices, and international trade can change the interactions of people, livestock, and wildlife, potentially influencing zoonotic disease risk.
The study of camel economies in eastern Ethiopia highlights the importance of a One Health approach that considers human, animal, and environmental health together.

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Tip Sheet: Should you be worried about ‘zombie deer’?

Mary Cunningham — Wed, 20 Mar 2024 17:28:05 +0000

Tip Sheet: Should you be worried about ‘zombie deer’? Mary Cunningham Wed, 03/20/2024 - 13:28

Attention Media: To speak to Amira Roess about chronic wasting disease, please contact Director of Marketing and Communications, Michelle Thompson at mthomp7@gmu.edu

911�� researcher Amira Roess discusses deer with chronic wasting disease, nicknamed "zombie deer," and what the risk to humans is.

Photo by Getty Images

Zombies have been found in a northern Maryland state park—zombie deer that is. The sick deer are not after human brains, but they could be harmful to humans who have contact with them.

We spoke with Amira Roess, professor of global health and epidemiology at 911��'s College of Public Health, to learn about zombie deer. Roess worked on deer-related illness while she was an epidemic intelligence service officer (i.e., an outbreak investigator) at the Centers for Disease Control. She is one of the principal investigators, along with Taylor M. Anderson of the College of Science on a study funded by the USDA examining the nature of human and deer contact in urban areas, specifically in the Washington, D.C., metropolitan area.

What are zombie deer?

What is referred to as "zombie deer" are actually deer infected with chronic wasting disease (CWD), which is a prion disease. Deer with CWD can appear very unsteady, stumbling a lot, and are often very thin. They may also show other symptoms related to neurological damage.

Prions are proteins that cause other proteins to unfold. Some describe them as virus-like proteins. When they infect a person or an animal they cause severe neurological damage. This leads to serious symptoms that get worse over time including unsteadiness, loss of the ability to speak or walk or swallow, and weight loss.

How worried should people be about getting prion disease?

Fortunately, the risk of prion disease from deer appears low if humans limit their contact with deer, especially their blood and nervous tissue. But this means that we must be very careful and vigilant.

Why haven’t we heard of prions before?

You may not remember hearing the word "prion,” but you might remember hearing about a prion called bovine spongiform encephalopathy (BSE), which was commonly called “mad cow disease” by many. That experience showed the world just how deadly prion diseases can be for humans.

During the BSE outbreak in England in the 1990s, humans became infected after eating beef products that had come from cattle infected with prions. Infected people lost their ability to walk, talk, and had very agonizing slow deaths that could only be diagnosed after death upon autopsy. That was the largest prion outbreak ever documented. What is very concerning is that in the U.S. when we test deer for chronic wasting disease, we increasingly find it.

Are you worried about outbreaks?

I am concerned that it is a matter of time before we find prion disease among people whose only exposure was through direct contact with deer. In the case of BSE, it was hypothesized that many infected individuals had first gotten exposed 10 or more years prior to their deaths. We believe that during those 10 or more years the prion slowly caused damage and went undetected until the damage got so extensive, that symptoms appeared.

How can we reduce our risk of contracting CWD?

Deer are wildlife, and as with all wildlife, we need to limit our contact with them. In many parts of the U.S., white-tailed deer are becoming habituated or accustomed to humans. They know that we generally don't hurt them, and increasingly we do things like feed them. But remember, deer are not pets—they have not evolved to be in such close contact with humans. They are still wildlife and deserve our respect and distance.

Do not approach deer and train your pets not to approach them either. If you have children or take care of children, make sure to teach them to be respectful of wildlife and to never approach deer or other wildlife. This is especially important if the animal appears hurt, sick, or disoriented. In that case, call 311 or your local wildlife office immediately to get a professional involved to help the animal.

Is there a group that is more at risk for chronic wasting disease?

Deer hunters are at an increased risk because of their close contact with the blood and nervous tissue of deer that they have hunted. Numerous educational resources about how to protect yourself from the risk of prions and other pathogens when hunting are now available. The best advice is to use personal protective equipment (PPE). If a deer appears sick, do not hunt it. Hunters can access information from their local games departments and in the USDA chronic wasting disease website.

Are there other animals that carry prions?

So far there have been reports of prion disease in humans, sheep, goats, cattle, mink, cats, and lemurs, among other mammals. Our knowledge about which other animals can be infected is limited by the fact that we don't have active surveillance for prion disease and most other diseases. What we know is very limited and confined to our experiences with cattle, deer, and other animals that have been found infected because of symptoms. Prions can remain in the environment for long periods of time, and they are very difficult to destroy.

What can we do to protect deer?

Remember that all wildlife deserve our respect and deserve to be left alone. Do not feed deer or other wildlife and remove all food sources (such as trash) to protect deer, raccoons, squirrels, birds and other animals.

When people approach an injured or sick animal, we often cause stress to the animal which then can make the animal sicker. If a deer looks sick, you should exercise extreme caution and not approach it. Instead, call 311 and report the deer so that it can be tested.

Studies have found that wildlife are losing their fear of humans, and this is linked to an increase in illness in these animals and also in people. Remember that wildlife carry numerous diseases that can harm people, including deer ticks that spread Lyme disease, and raccoons, coyotes, and foxes that spread rabies.

To speak to Amira Roess about chronic wasting disease, please contact Michelle Thompson at mthomp7@gmu.edu

Amira Roess is a professor of global health and epidemiology at 911��'s College of Public Health, Department of Global and Community Health. She is an epidemiologist with expertise in infectious diseases epidemiology, multidisciplinary and multi-species field research and evaluating interventions to reduce the transmission and impact of infectious diseases. Roess currently oversees several longitudinal studies to understand emergence and transmission of zoonotic infectious diseases globally, including the emergence and transmission of Campylobacter (with support from The Bill and Melinda Gates Foundation), MERS-CoV (with support from the US National Science Foundation), and the development of the microbiome during the first year of life. She studies links between food animal production and emerging infectious and zoonotic disease emergence globally, and mHealth (especially apps) technology integration and evaluations to reduce the impact of infectious diseases outbreaks, promote health care and health reduce disparities.

Some of her deer-related work appears in these journal articles:

More resources about chronic wasting disease can be found here:

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Tick Dragging and Water Filtration—Not Your Typical Spring Break

Mary Cunningham — Mon, 25 Apr 2022 16:58:47 +0000

Tick Dragging and Water Filtration—Not Your Typical Spring Break Mary Cunningham Mon, 04/25/2022 - 12:58

Global Health Alternative Spring Break class gives students hands-on infectious disease research experience in Kenya

What did you do over spring break? “Tick dragging and water filtration” is not an answer you’ll hear often, but 11 students in Michael von Fricken’s GCH 491/GCH 591 Public Health Study Abroad course did just that in Laikipia, Kenya.

Participants included undergraduate and graduate students and ranged from those hoping to confirm their chosen career path to those looking to dig deeper into the global health path they are on. Students studying community health, science, bioengineering, environmental science, and biodefense participated in the course subtitled “Research Methods of Vector-borne Disease Surveillance.” Additionally, two PhD students from the Institute of Primate Research participated.

“I wanted to figure out what I wanted to do with my career. Infectious diseases interested me and I wanted to see what was out there and how it translated into a career,” said Marcara Wright, a sophomore a Global and Community Health major.

Abby Lilak and Marcara Wright working on a water filtration system

Students studied mosquito and tick vector-borne diseases and water filtration of East Africa. Their work contributed to ongoing research that von Fricken, assistant professor in Mason’s Department of Global and Community Health, is participating in, with partners in Kenya (Mpala Research Centre) and at the Smithsonian Institution Global Health Program. Students took part in a Department of Defense-funded effort to collect leeches, ticks, water, and soil samples from shared waterholes on ecologically protected grasslands using a One Health approach. By sampling at the human/wildlife/environmental interface, students were learning firsthand about transmission pathways for emerging zoonotic diseases while participating in ongoing surveillance efforts being carried out in Kenya.

“This was my first time tick dragging [collecting ticks by dragging a cloth through the environment]. We went to a watering hole and we dragged for ticks. I didn’t know that ticks could be so small, and it was hard to find them,” said Wright. “We were looking for ticks to analyze them to determine how they are affecting the population and to look for any emerging diseases that might be coming up through the ticks to the human population. This is important to try to get ahead of any diseases so that they will not affect the population so harshly.”

Students spent eight days camping and working on protected Kenyan conservation ranches.

Students spent eight days camping and working on protected Kenyan conservation ranches being trained in field and lab techniques specific to surveillance of vector-borne diseases (such as African tick-bite fever and East Coast fever) and bacteria and viruses that might be circulating in waterholes where multiple domestic and wildlife species congregate. They examined the biological, social, and environmental risk factors of disease exposure in an international setting.

“This work is meant to give a quick response to monitoring what is present in environments and how that can relate to other animals or communities that interact animals or these environments,” said Abby Lilak, a first-year student in the master of science in global and community health program. “For example, if there is a large number of pathogens found in the ticks, providing findings and additional education about pathogens to pastoralists would be a way of informing populations which may be affected.”

In addition to looking for diseases in ticks, they also took water samples in order to look for bacteria or viruses that may transfer from the water to animals, and eventually to humans.

“Before the trip I attended trainings at the Naval Medical Research Center, so in Kenya I [led] the water filtration project. I was very fortunate to have three Mason students who decided to learn about the filtration system and help me record samples, run filtrations, and troubleshoot challenges,” Lilak continued. “Within our trip, each of them could efficiently run water filtrations by themselves. Having a lovely experience with equally eager students while being able to have time to laugh and joke was one of my favorite memories.”

Having the opportunity to work directly in an international setting improved students’ cultural competency, helped build their research confidence, and reiterated the importance of understanding the drivers behind emerging diseases.

Abby Lilak with a water filtration system.

“I learned a lot of technical skills and the ability to collaborate and adapt together as a group. Having an environment of students and professionals all with a passion for infectious disease allows you to challenge your perceptions and gain deeper understanding by interacting with each other,” Lilak said.

Students also appreciated being able to explore the culture in Keyna outside of the lab. From the food to the Mt. Kenya Wildlife Conservancy, home to the endangered Mountain Bongo, students explored Kenya alongside local scientists, creating an opportunity for cross-cultural exchange.

Von Fricken previously taught this alternate spring break course twice prior to the COVID-19 pandemic, and it has been on hold for the past two years. Though the pre- and post-departure protocols are much more detailed than before the pandemic, von Fricken and his students were able to do similar global research work that they were doing in 2019.

Though it wasn’t the typical spring break, students on the trip learned a lot and returned more energized to continue their studies.

“All the work done during this trip is related to One Health, which is an approach that makes you look at the interconnectedness of animals, humans, and environment and how that pertains to health. In the future, I would like to return to East Africa and conduct surveillance work on infectious diseases with a strong One Health approach. This trip remotivated me to continue my career path,” said Lilak.

“I definitely learned global health something I want to do for a living, and might even go for my master’s. I know now that I want to work with infectious diseases,” Wright said.

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New One Health Scholarship Opportunity for MPH, MS-Global Health Students

John Brandon Cantrell — Wed, 18 Aug 2021 19:24:18 +0000

New One Health Scholarship Opportunity for MPH, MS-Global Health Students John Brandon C… Wed, 08/18/2021 - 15:24

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Students interested in studying the interconnections of health among plants, animals, and humans are encouraged to apply for this scholarship by September 27.

The College of Health and Human Services is pleased to announce a new scholarship opportunity for Master of Public Health (MPH) and Master of Science in Global Health (MS-Global Health) students who are passionate about studying the interconnections of health among plants, animals, and humans. Thanks to the generosity of Michael von Fricken, professor of Global and Community Health, the One Health Scholarship will provide a selected graduate student with funding and/or support to pursue a research project relating to the One Health initiative.

“I wanted to create an opportunity to support our graduate students interested or actively engaged in infectious disease research,” von Fricken said. “This is also a way to identify promising students who want to become more involved in One Health, which will be important as we grow the One Health discipline here at Mason.”

As an incentive to get students interested in One Health, the scholarship will provide graduate students with additional funding to offset costs related to their research. “This is one of a small number of scholarships that benefit CHHS graduate students," said Shannon Donohue, assistant director of development. "We are grateful to Dr. von Fricken for supporting student success at the graduate level."

According to the Centers for Disease Control and Prevention, the One Health Initiative is “a collaborative, multisectoral, and transdisciplinary approach—working at the local, regional, national, and global levels—with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment.”

The One Health Initiative is an important field of research because the majority of emerging diseases in humans are zoonotic in nature, meaning they originate in animals. “When these spillover events occur, it is important that we have trained personnel who understand the importance of One Health and are open to listening to perspectives from experts across disciplines," von Fricken said. "Conducting research within the human-animal-environment interface can provide important insights to disease emergence to better prepare for future pandemics.”

Undergraduate students who are interested in One Health are invited to register for Introduction to One Health (GCH 305). This course occurs every spring and is co-taught by three lecturers, each with specific backgrounds related to human, animal, and environmental health.

The deadline to apply for the 2021-2022 One Health Scholarship is Monday, September 27, 2021. To apply, please visit the Fall 2021 Scholarship Opportunities webpage. Applications for the 2022-2023 academic year will be available from December 2021 to May 2022.