A Career in International Veterinary Medicine

The career of veterinary epidemiologist Dr. Jeffrey Mariner, V87 (he/his), has taken him to five continents, where he has either participated in or led various disease surveillance and control programs. His most notable accomplishment was the development of a heat-stable rinderpest vaccine, which led to its global eradication in 2011. According to the Food and Agriculture Organization of the United Nations (FAO) it was just the second virus (joining smallpox) to achieve this status.

In late October, Mariner presented an International Veterinary Medicine (IVM) forum talk titled, “A Career in International Veterinary Medicine,” to students enrolled in either Cummings School of Veterinary Medicine at Tufts University’s IVM signature opportunity or its post-graduate certificate program.

Through stories of his worldwide experiences, Mariner shared lessons he has learned through a career in One Health—recognizing the connection among the health of people, animals, and the environment—and offered advice to the audience about how to impact others. 

Starting work on rinderpest at Cummings School of Veterinary Medicine
Thirty-six years after earning a Doctor of Veterinary Medicine from Cummings School, Mariner pointed to the relationships that he built which served him well throughout his career. “Tufts [University] played a strong role in getting me started,” Mariner shared, as he arrived on campus with an interest in livestock and was influenced by several veterinarians. “I learned about a livestock project in Niger from a strong group of professors involved in international livestock development and disease control,” he explained. “They gave me my first work on rinderpest and got me started in the field.”

After earning his D.V.M., Mariner worked at Plum Island Animal Disease Center (off Long Island, New York), and in two years he helped to develop the heat-stable rinderpest vaccine, then went to Africa to put the vaccine into production. There he gained interest in working as a development practitioner. “I found that the real challenges were how people worked together, rather than the technical issues associated with the vaccine,” he said.

As Mariner gained interest in disease modeling and epidemiology, he earned a doctorate from the University of Guelph (Ontario, Canada) and became an epidemiologist, constantly gathering knowledge with the goal of contributing to rinderpest eradication. “You can be a good technologist, but if you want to have impact you need to get into the social dimensions and understand the hurdles to implement technology and institutional change,” he shared. Mariner cited examples in South Sudan, Ethiopia, and Uganda, where they worked carefully with collaborators to ensure that the vaccine would be used effectively to eradicate the disease.

Oftentimes, they needed to gain information from local community members and empower community health workers to achieve success in each area where rinderpest was prevalent. Mariner cautioned that with the implementation of any animal health project, consumers and producers are only the first entities that need to be considered. Laws and regulations, culture and customs, attitudes, and expectations can influence a plan. Implementers must also collaborate with governing bodies and boards, public and private veterinarians, as well as domestic and export livestock value chain stakeholders while assessing how human health will be affected.

“When trying to affect change, you need to think about all these players and how they’re interacting,” Mariner said. “If you create a technical tool and just throw it out there, it will probably sink … You need to devise win-win scenarios … each set of participants requires incentives to embrace change. They need to see how it will be good for them.”

To become effective in their One Health work, Mariner and his colleagues evolved a technique called participatory epidemiology. Using a participatory rural appraisal, non-governmental organizations (NGOs) would learn how to work with a community by learning from its farmers, which proved to be highly accurate and effective when used for the rinderpest eradication program.

During the process of ridding the world of this disease, Mariner’s team institutionalized community animal health, developed participatory epidemiology, and gained widespread acceptance within the field. Rinderpest had infected cattle and buffalo herds from the 18^th to 20^th century.

“I pushed from the laboratory through all the work in between to see the vaccine implemented,” Mariner explained. “This was a Tufts accomplishment. For less than $1 million we had this tremendous impact on a program that probably cost $500 million.” 

International Livestock Research Institute and PPR
During a decade of work for the International Livestock Research Institute (ILRI), based in Kenya, Mariner persuaded the organization to adapt to his mode of operation. “Everything I did was focused on solving a problem to advance change on the ground,” he said. “I asked, ‘What do I want to achieve?’ Then I researched to make that happen.”

He first worked in Indonesia on Highly Pathogenic Avian Influenza (HPAI), a contagious disease that is often fatal to chickens, then became involved in some of the work on the eradication plan for Peste des petit ruminants (PPR), a close relative of rinderpest that affects small ruminants. “I took the rinderpest method and applied it to PPR and made a thermostable vaccine,” he said. “And that was the first tangible product that ILRI had produced in 30 years. It took about a year because I targeted the right thing.”

Most recently, Mariner has worked on PPR episystems for the Food and Agricultural Organization, a specialized agency that leads international efforts to defeat hunger and improve nutrition and food security. “Targeting PPR episystems requires understanding the source of an infection,” he explained. “You need to understand how the disease is circulating in the region, then focus on interrupting the transmission. You don’t need to vaccinate everywhere but look for those critical points in the transmission.”

Technological advancements have enabled a more efficient response to address the spread of diseases, such as PPR, according to Mariner. “With the tools we have today we can use the participatory techniques to map it out, rapid tests to confirm where it is, and then bring it into genomics—partial sequencing, which is very inexpensive—and send it out to a commercial service and get your disease map.”

This enables the research team to see the relationship with the virus, determine where it came from, and use divergent analysis to see if it is present in wildlife. “Then we can completely and objectively map out these episystems,” Mariner explained. “We used to have to do it by feel and subjective mapping, but now we can be objective with the genomics.” This identifies where the vaccination should be targeted.

USAID’s Bureau for Humanitarian Assistance
Mariner also worked on a project with Tufts for the U.S. Agency International Development’s (USAID) Bureau for Humanitarian Assistance, looking at the potential for combining community health workers and community animal health workers in various African countries. 

In some locations people practicing pastoralism are “living One Health,” said Mariner. “They are completely dependent on the environment, with their livestock, living off their herds and moving around, and their health issues are completely intertwined. For them, there are no separate silos.” 

Ultimately, Mariner explained, for One Health to work the factions need to merge into a true integration. “Collaboration is where separate power centers agree to play nice, but integration is where the real advantages are, and we are slowly moving in that direction.”

His international career has had a profound effect on Mariner. “I’m a completely different person, having worked outside the United States for 30 years,” he explains. “I’m still American, but the people that I feel the most comfortable around are others who have worked internationally for a long time … My work has provided me with an opportunity to improve the world in my own way.”

Mariner has recently retired from his position as a research professor in Cummings School’s Department of Infectious Disease and Global Health. He plans to continue his work on PPR and the USAID Strategies to Prevent Spillover project, as well as consultant work for the FAO and the Bill & Melinda Gates Foundation.