Research from Cummings School of Veterinary Medicine helped rid the world of a deadly virus. That experience may help prevent future disease outbreaks
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Permanently wiping out a disease is tricky business. Polio, measles, mumps—all have effective vaccines, yet they persist in certain pockets around the world. To date, the World Health Organization considers just two viruses as successfully eradicated: smallpox and rinderpest.
It may not be a household name, but rinderpest was once a deadly scourge that infected cattle for millennia, killing millions of animals. The United Nations announced its eradication in 2011, after the last outbreak had been reported about a decade earlier.
Jeffrey Mariner, D.V.M., V87, then a veterinary epidemiologist at Cummings School of Veterinary Medicine at Tufts University, and his colleagues were instrumental in the quest to permanently end the disease.
“For Dr. Mariner and his colleagues at Cummings School and around the world, the collaborative efforts required to eliminate rinderpest, like smallpox, were a truly tremendous achievement in uniting innovative social approaches with extensive community level efforts and technological advances,” said Jonathan Runstadler, D.V.M., Ph.D., professor and chair of the Department of Infectious Disease and Global Health at Cummings School of Veterinary Medicine.
Today, 15 years after the official eradication announcement, Mariner says the successful effort to rid the world of rinderpest offers enduring insights.
Despite retiring from Tufts, Mariner continues his work, now mostly focused on combating goat plague, or peste des petits ruminants (PPR). Like rinderpest, the disease is highly contagious and can infect an entire herd. Passing on knowledge learned from direct experience—like the importance of grassroots disease monitoring and strategic vaccination, both of which helped eradicate rinderpest—remains an important element of keeping current and future diseases in check, he says.
“International organizations have had to relearn some of the lessons of rinderpest in their current efforts to eradicate PPR,” Mariner said.
An Enduringly Nasty Virus
Rinderpest, a German word meaning “cattle plague,” can be traced back as early as the Roman Empire. In the centuries when the virus was active, it ran through herds from Europe into Asia and Africa. When the disease struck, it often killed the entire herd.
The disease was so economically devastating that it’s recognized as the cause of several historic famines. In the 18th century, rinderpest killed 200 million cows in Europe. In the 19th century—after colonialism spread the disease—rinderpest culled about 90% of plow oxen in Ethiopia. Rinderpest itself has no effect on human health, but the resulting famine killed one-third of Ethiopia’s population.
“Without cattle to plow fields and fertilize crops with dung, the once-fertile Ethiopian lands became a graveyard,” wrote researchers from the National Institutes of Health in a 2011 paper.
Attempts to develop a vaccine, which began as early as the 18th century, provided some protection, but not a full cure. It wasn’t until the middle of the 20th century that the first effective vaccines were introduced. Shortly after, the U.N. Food and Agriculture Organization began a worldwide campaign to inoculate animals, shipping vaccines and brokering meetings between countries to discuss collaborative vaccination campaigns.
Soon, the number of global rinderpest infections fell precipitously, but occasional outbreaks continued.
“The elimination of rinderpest has had enormous impact on the lives of people and their animals. It serves as an example for work on many other viral diseases that require similar tactics of combining laboratory and social science with ground level efforts to prevent outbreaks and eliminate disease.”
A Tipping Point
Complete eradication remained out of reach until a technological breakthrough—along with what Mariner and other researchers have called “social innovations”—made it possible.
Most vaccines require refrigeration, and the rinderpest vaccine was no exception. But in many places where the disease was common—rural areas with cattle ranching—refrigerated shipping was expensive and complex.
“It was extremely challenging to keep the vaccine cold while traveling to isolated areas,” Andy Catley, Ph.D., research professor emeritus at Tufts, previously explained to Tufts Now. “It required refrigeration facilities, ice machines, cold boxes and fleets of vehicles. They needed an easier way to deliver the vaccine.”
In the 1980s, Mariner and his colleagues earned grant funding from the United States Agency for International Development (USAID) to experiment with ways to make a vaccine that did not require refrigeration. His team worked for two years and eventually developed a method to freeze-dry the vaccine. As a result, it could stay effective at temperatures as high as 98 degrees Fahrenheit and could last 30 days without refrigeration.
That innovation made it possible to deliver vaccines to a wider array of far-flung places, but it didn’t necessarily make it easier. Past mass vaccination attempts had failed to reach herders and ranchers in remote areas where it was harder to transport the vaccine, regardless of refrigeration.
So, the scientists engaged in a more targeted and strategic approach and went directly to those remote areas. Researchers helped train people in these communities to provide the vaccine and relied on their knowledge to decide how and when to distribute it. These efforts increased vaccination in herds that had been missed during previous campaigns. Locals then monitored for signs of disease after vaccination occurred.
“I don’t know if we would have succeeded if we didn’t have that approach in place: the heat-stable vaccine combined with new appropriate delivery systems,” Mariner said in a 2019 interview. The successful eradication, then, relied on both science and collaboration, and a tool called participatory epidemiology, which incorporates both researchers and stakeholders.
“The elimination of rinderpest has had enormous impact on the lives of people and their animals,” said Runstadler. “It serves as an example for work on many other viral diseases that require similar tactics of combining laboratory and social science with ground level efforts to prevent outbreaks and eliminate disease.”
