New analysis published in the academic Science journal traces the cause of the recent global eradication of deadly cattle disease, rinderpest, and credits local African herders for their insight and assistance
The study explains how the herders enabled the development of a new, heat-resistant vaccine and guided scientists in deciding which animals to immunise and when.
The study provides new insight into how the successful battle against rinderpest in Africa, the last stronghold of the disease, might be applied to similar diseases that today ravage the livestock populations on which the livelihoods of one billion of the world’s poor depend.
Capable of wiping out a family’s cattle in just a few days, rinderpest was declared vanquished in May 2011. After smallpox, it is only the second disease, after smallpox, (and the first livestock disease) ever to be eradicated from the earth.
“The elimination of rinderpest is an enormous triumph against a disease that has plagued animals and humankind for centuries,” said Jimmy Smith, director general of the International Livestock Research Institute (ILRI).
“Science succeeded despite limited resources, and we now know how.
“We are committed to applying the lessons in this study to making progress against other similarly destructive livestock diseases.”
According to the analysis, which was conducted by international scientists coordinated by the ILRI, the eradication of rinderpest happened thanks to the development of an effective temperature-stable vaccine, collaborations between veterinary health officials and cattle farmers to deliver those vaccines, and reliance on the knowledge and expertise of the local herders to determine the location and movement of outbreaks.
The origins of Rinderpest, known as ‘cattle plague’ in English, are thought to lay in the dense cattle herds of Central Eurasia more than two millennia ago and the disease subsequently spread through warfare and trade to cattle in Europe, Asia and eventually Africa.
Caused by a virus related to the one that causes measles and canine distemper, rinderpest infected cows, water buffalos and other cloven-hoofed animals, leading to a high fever, severe diarrhoea, then dehydration and emaciation.
The pathogen could kill 90 per cent of a herd, wiping out an entire farm’s livestock in just a matter of days. There was no treatment.
While rinderpest is not dangerous to human health, its impact on humanity has been significant.
The first major contributing factor to eradication, which was identified by the analysis, was a major improvement made to an existing rinderpest vaccine.
While the original vaccine was safe, effective, affordable, and easy to produce, it needed to be refrigerated—making it nearly impossible to transport it to remote rural villages.
With the development of a new heat-resistant vaccine formulation in 1990 that could be stored at 37°C for eight months, and in the field without refrigeration for 30 days, scientists had a tool that would become the cornerstone of the eradication effort in remote pastoral areas of Africa.
According to ILRI’s Jeffrey Mariner, the analysis’ lead author and inventor of the temperature-stable rinderpest vaccine, it was the role played by pastoralists that truly helped eradicate rinderpest.
As part of a public-private-community partnership, Mariner and his colleagues trained what they called community-based animal health workers, or CAHWs, local pastoralists who were willing to travel on foot and able to work in remote areas, on how to deliver the new vaccine.
The CAHWs carried the vaccine from herd to herd, immunising all of the cattle in their communities.
The local herders performed as well, if not better, than the veterinarians at vaccinating the herds.
In fact they often achieving higher than 80 per cent herd immunity in a short time which was remarkable for a disease that had caused major issues for so many years.
The pastoralists were not only very, very good at delivering the vaccine, but that they also knew more about the disease and how to stop it than many of the experts.
“We soon discovered that the livestock owners knew more than anyone, including government officials, researchers or veterinarians, where outbreaks were occurring,” Mariner said.
“It was their expertise about the sizes of cattle herds, their location, seasonal movement patterns and optimal time for vaccination that made it possible for us to eradicate rinderpest.”
Based on their immense expertise about migratory patterns and in recognising early signs of infection, the herders were able to pinpoint, well before scientists ever could, where some of the final outbreaks were occurring, often where conventional surveillance activities had failed to disclose disease.
Harnessing this knowledge of rinderpest through “participatory surveillance” of outbreaks to CAHW delivery of vaccination proved to be the most successful approach to monitoring and controlling the disease. It effectively removed the disease from some of the hardest-to-reach, but also most disease-ridden, communities.
In their analysis, Mariner and colleagues consider how the lessons learned from battling rinderpest can be applied to protect livestock from other infectious agents, particularly peste des petits ruminants (PPR) or ‘goat plague’.
As a result, ILRI and the Africa Union/Interafrican Bureau for Animal Resources are planning to host the next meeting of the PPR Alliance, a partnership of research and development organisations who prioritise PPR, in Nairobi in early 2013.
Go to www.ilri.org for further details.