Fast and accurate diagnosis and monitoring of animal diseases can make the difference between living in poverty and having a steady source of food and income. In countries where livestock play a key role in everyday life and development, a network of laboratories called ‘VETLAB’ offer scientists an avenue for diagnosing and monitoring diseases using nuclear and nuclear-derived techniques to help ensure a stable future for farmers. The network is financed through the Peaceful Uses Initiative (PUI) and the African Renaissance Fund.
“The farmer is the one who benefits. The more diseases we control, the more animals the farmers have. And if they have more animals, poverty is reduced,” said Christopher Simuntala, Head of the Central Veterinary Research Institute in Lusaka, Zambia, who learned how to use these nuclear and nuclear-derived techniques at a training course held by the IAEA in partnership with the Food and Agriculture Organization of the United Nations (FAO).
One billion people, mostly pastoralists in South Asia and sub-Saharan Africa, depend on livestock for food and livelihood, according to the FAO. Many animal diseases are highly contagious and can spread extremely quickly within a country and across borders, hindering trade and, in some cases, affecting public health.
“Molecular diagnosis helps us understand the spread of diseases,” Simuntala said. “We are able to tell whether a disease originated in our area, or started elsewhere and then moved to our country, and also which animals are carrying the diseases. This will help us in predicting threats and controlling disease.”
Nuclear-based technologies can be used to detect viruses like capripox disease, peste des petits ruminants (PPR), African swine fever, foot and mouth disease, Newcastle disease, and highly pathogenic avian influenza in a single pathogen or a multi-pathogen detection system.
“Conventional methods used in many developing countries can detect the viruses, but this takes a long time and cannot determine its behaviour or character,” said Charles Euloge Lamien, specialist in animal health at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. “And viruses change. With the use of full genetic sequencing, the detection method is more refined and sophisticated.” (See The Science box)
Going after PPR
One of the most damaging livestock diseases in Africa, the Middle East and Asia is the highly contagious and widely spread PPR virus. It kills thousands of sheep and goats per year and causes annual economic losses estimated at over US $1.4 billion. 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 (OIE).
A global effort is now underway to eradicate PRR by 2030 using nuclear and other techniques, and the ‘VETLAB’ network of animal health laboratories will play a critical role in this effort. The Global Control and Eradication Strategy is fashioned after the successful global eradication programme for rinderpest, a virus closely related to PPR, which was declared eradicated in 2011 with the help of nuclear techniques and the VETLAB network.
“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 to monitor the spread of PPR.”
Among the nuclear-related techniques 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. The laboratories comprising the VETLAB network provide training in these techniques, as well as support in early and rapid diagnosis and control of PPR.
Connect, exchange, contain
The VETLAB network of animal health laboratories connects scientists and laboratories across borders with the IAEA, FAO, OIE and other partners, and helps to ensure that advanced capacities are available to stay ahead of these diseases.
Through this network, scientists share their knowledge to more dynamically adapt strategies and further research and development that is essential to monitoring and containing the spread of transboundary animal and zoonotic diseases. According to Sabenzia Nabalayo Wekesa, Head of the Molecular Laboratory of the Central Vet Laboratories in Nairobi, Kenya, sharing diagnostic data is an important element of the entire animal disease control process. It allows for close collaboration with other countries and helps compare results, learn what diseases are circulating elsewhere, and prevent them from spreading.
In cases where key veterinary capacities are lacking, the VETLAB network facilitates scientific training and assists laboratories through providing equipment and technical support. Laboratories throughout the VETLAB network also offer rapid and early diagnostic and control services to other laboratories that lack the capacity to do this themselves. Together, this translates into more improved national and regional veterinary services and, ultimately, more effective animal disease control.
Sequencing is a nuclear-derived technique that involves finding the way the nucleic acid (RNA and DNA) information inside pathogens is gathered. Organisms, including viruses, have genetic material. Through genetic sequencing, scientists can find out how the information inside the genetic material is structured and how it behaves. This not only helps to diagnose a disease, but can also disclose its origin and evolution.
Radioactive labelling was the method used for the first molecular characterization of a virus genome, and it is still the preferred technique where high levels of sensitivity and specificity are needed, and where a single pathogen among a million similar micro-organisms has to be identified. However, in most cases, a simpler method, involving a less sensitive labelling approach using dyes, chromophores or mass spectroscopy can be sufficient to identify the pathogen threat.
These nuclear-based tools and techniques are also used for detecting diseases like the Ebola and Zika viruses.