Vets vaccinate a young goat in Congo against ovine rinderpest.

© FAO/Xavier Farhay

Bane of sheep and goat farmers targeted for eradication

Animal health specialists meeting in Abidjan, Ivory Coast, yesterday agreed to try to rid the world of peste des petits ruminants (PPR), a viral disease devastating goat and sheep flocks throughout Africa, the Middle East, and Asia. Control efforts have fallen short. The time has come for a "bolder next step," said José Graziano da Silva, director-general of the Food and Agriculture Organization (FAO) of the United Nations, at the meeting FAO organized with the World Organisation for Animal Health (OIE) to kick off a global eradication program.

Also called ovine rinderpest, PPR kills up to 90% of the animals it infects within days. The virus has spread rapidly over the past 15 years and is now present in 70 countries, putting 80% of the world's more than 2 billion goat and sheep at risk. FAO estimates that the disease causes more than $2 billion in losses annually and is an economic disaster for the small herders and poor rural households that depend on the animals for milk, meat, wool, and leather both for their own use and for trade.

The eradication plan envisions a staged approach. The assessment phase requires determining the numbers and locations of flocks most at risk and building veterinary capabilities. Then control efforts relying on voluntary vaccination will hopefully lead to an endgame in which authorities might enforce vaccination. The final step would be for countries to verify that there have been no PPR cases within their borders for at least 24 months. FAO and OIE believe they will need $4 billion to $7 billion over the next 15 years to accomplish their goal.

There is a reliable PPR vaccine, though the organizations would like to see improvements made to extend its shelf life in hot climates. They note that strengthening veterinary capabilities would also benefit efforts to combat other diseases, such as foot-and-mouth disease, and improve animal health overall. 

The plan builds on lessons from the successful eradication of rinderpest, a disease caused by a related virus that had plagued cattle for millennia. After several failed attempts to control rinderpest, FAO launched a Global Rinderpest Eradication Programme in 1993 and declared the disease vanquished in 2011. It was the first time in history that an animal virus had been eradicated.

Paul Rossiter, a U.K.-based veterinary consultant who was involved in the rinderpest campaign, notes that the PPR effort starts with a number of advantages. Diagnostic and tracking tools not available in the early days of the rinderpest program are now ready to go for use against PPR. These include tests for antibodies and to identify different viral strains. But he also flags challenges in the field. Many herders and local vets are still unfamiliar with PPR, which can be confused with other infections. And the large numbers of sheep and goats, as well as the rapid replacement rate of the animals, will complicate efforts to attain sufficient levels of herd immunity to stop virus transmission. Thus Rossiter believes that a central challenge facing the PPR eradication program will be developing wider ranging and more imaginative vaccine programs.