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Global Strategy to Fight Global Ruminant Pest Uses Nuclear Techniques

Global Strategy to Eliminate Peste des petits ruminats (PPR) IAEA FAO

Peste des petits ruminants (PPR) is a highly contagious, widely spread disease that kills thousands of sheep and goats per year and causes annual economic losses estimated around US $1.4 billion. (Photo: IAEA)

Nuclear techniques successfully used in the global eradication of rinderpest by 2011 will take centre stage in the elimination of a major small ruminant disease in Africa, the Middle East and Asia.

A burden to over 300 million people worldwide, peste des petits ruminants (PPR) is a highly contagious, widely spread disease that kills thousands of sheep and goats per year and causes annual economic losses estimated at over US $1.4 billion. A global effort is now underway to eradicte PRR by 2030 using nuclear techniques through a Global Control and Eradication Strategy, or Global Strategy, for short. The Global Strategy is fashioned after the successful global eradication programme for rinderpest, a closely related virus to PPR, which was declared eradicated in 2011 with the help of nuclear techniques.

Under the Global Strategy, the Food and Agriculture Organization of the United Nations (FAO), the IAEA and their partners will work together to eliminate PPR, improving the livelihoods of people and economies in Africa, the Middle East and Asia that rely on sheep and goats, boosting food security in the process.

“One of the major constraints faced by those involved in the livestock sector is PPR,” said Berhe Tekola, Director of the FAO Animal Production and Health Division. “Nuclear techniques will be indispensable in eradication efforts, through the use of isotopic techniques in vaccine development and monitoring the spread of PPR.”

PPR is considered to be one of the most damaging livestock diseases in Africa, the Middle East and Asia. The virus can spread through entire regions and cause a morbidity rate of up to 100 per cent and a mortality rate of up to 90 per cent in infected ruminants — sheep, goat and their relatives in the wild. In less severe cases, the virus can hamper the development of young ruminants and weaken the immune defences in adults. First reported in 1942, PPR has since spread to over 70 countries and 50 others are considered at risk, according to the FAO and the World Organisation for Animal Health, which estimates global economic losses at over $US 1.4 billion.

Originally thought to be the same as the rinderpest disease — a Morbillivirus that affects cattle, domestic buffalo, and other even-toed, hoofed mammals like large antelope and deer — PPR was identified as a distinct disease in 1986. Recognizing this important distinction allowed scientists to discover a specific clone of PPR that proved to be a safe candidate for a PPR vaccine.

Learning from differences

Though the diseases are distinctly different, their shared characteristics and behaviour have made the experiences from the successful eradication programme for rinderpest a very effective starting point for the Global Strategy, said Gerrit Viljoen, Head of the Animal Production and Health Section at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The Global Strategy adapts key components of the rinderpest programme to addressing PPR, including, among others, the nuclear-related diagnostic and monitoring techniques, the technical and scientific laboratory networks and services for monitoring and diagnosing animal diseases and for developing control tools, as well as national, regional and international coordination mechanisms.

The Joint FAO/IAEA Division provides equipment and trains scientists on how to use and calibrate tools nuclear and other diagnostics, monitoring, and testing for the disease and vaccines. (Photo: D. Calma/IAEA)

“One of the keys to the success of the global rinderpest programme was the use of a highly efficient rinderpest vaccine, providing lifelong immunity against all rinderpest virus strains,” said Adama Diallo from the PPR Global Strategy Secretariat. “A similar vaccination tool does exist for the control of PPR; indeed, PPR vaccines based on a live, less virulent version of PPR that provide long-lasting protection in correctly vaccinated animals are currently available. As vaccines are disseminated, nuclear-related tools help to diagnose and monitor the spread of the disease and to track the effectiveness of the vaccines, and the lessons learned from the rinderpest campaign give us a distinct advantage in this process.”

Among the nuclear-related techniques to be employed are nucleic acid-based diagnostics and serum-based virus tests, which can be used to diagnose and monitor PPR, as well as for developing, adapting and validating vaccines and diagnostic technologies and procedures. These techniques and vaccines are still being researched and developed to ensure their effectiveness for widespread practical application, but as they are refined, they will be distributed with key support from the FAO/IAEA laboratories to the countries involved in the Global Strategy, Viljoen said.

Unique in a network of support

The transboundary nature of PPR makes collaboration across borders key. A series of national, regional and international collaborations of countries, laboratories and partner organizations is an important component of the Global Strategy. These collaborations facilitate essential knowledge exchange in monitoring and managing PPR to stop its spread and to further research and development to dynamically address the disease.

One critical component of the Strategy comes through the Joint FAO/IAEA Division’s so-called ‘VETLAB’ network of animal health laboratories that will provide early and rapid diagnosis of PPR. “The Joint FAO/IAEA Division, with its dedicated laboratory and its experience in the evaluation and validation of rinderpest diagnostic and surveillance technologies, is the technical support and reference laboratory of choice, together with the world PPR reference laboratories, for the early and rapid diagnosis and control of PPR,” said Liang Qu, Director of the Joint FAO/IAEA Division.

The Joint FAO/IAEA Division provides Member States, other laboratories and partners with equipment and trains scientists on how to use and calibrate tools for diagnostics, monitoring, and testing for the disease and vaccines at a national level. The laboratories also conduct research to further progress and development to stay ahead of the disease, as well as improve national and regional veterinary services. So far, the laboratories have already developed a new cell line to propagate and characterize the PPR virus and diagnostic tests related to PPR that are now being used commercially.

Last update: 26 July 2017

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