The application of nuclear techniques for diagnosis and for pinpointing migratory habits of birds is contributing significantly to the worldwide battle against avian influenza.
Avian influenza is a deadly disease. The Highly Pathogenic Avian Influenza Virus of H5N1 (HPAIV-H5N1) subtype is extremely contagious and particularly aggressive for humans, killing 60-70% of people infected. HPAIV-H5N1 is mainly carried by birds and people become infected through contact with infected birds, faeces, contaminated surfaces or eating undercooked poultry, eggs or blood from infected birds. Nuclear diagnosing techniques have aided in containing the virus to a few regions in the world and prevented pandemics with possible catastrophic consequences.
Experts at the IAEA have employed nuclear techniques to identify the spread of HPAIV-H5N1 by using early and rapid diagnostic tools and by measuring the stable isotope ratios in the feathers of migratory birds.
Multidisciplinary approaches to establish early and rapid diagnosis, using molecular techniques and stable isotope analysis to evaluate the migratory pathways of wild birds may contribute to detect the spread of the virus, before it is transmitted to other bird and/or human populations.
"The power of nuclear technologies is that one can detect the presence of the virus even if a few of its RNA molecules are present in a sample," Mr. Gerrit Viljoen, Head of the Animal Production and Health Section in the Joint FAO/IAEA Programme in Nuclear Techniques in Food and Agriculture, pointed out.
"This means that we do not need to wait until a large proportion of the population is infected and it is too late, but can take early and rapid measures to stop the spread of the disease," he added.
Since 2006, the IAEA has been holding regional training courses on early and rapid diagnosis at its Animal Production and Health Laboratory in Seibersdorf, Austria. Through these training courses, scientists from all over the world learn to use and apply multidisciplinary diagnostic approaches globally, not just for avian influenza but for a range of other diseases as well. These include foot and mouth disease, rabies and other diseases transmitted from animals to humans (zoonotic diseases).
At the same time, IAEA experts have developed new nuclear-based techniques to improve tracking and analysis of birds' migratory behaviours. Migratory pathways of wild birds are sometimes measured in tens of thousands of kilometres. To effectively stop the spread of avian influenza, it is extremely important to know where the disease originates from or how far it can or has spread.
Different geographic regions have unique isotope compositions. Based on the food and water uptake at a specific geographical area, the stable isotope ratios in the feathers of birds will correlate to that of a specific geographical area, thus enabling scientists to define the migratory pathway of those birds. This data is then uploaded onto a global database that is available to all interested parties. This is especially important - once a bird population has been confirmed as a carrier of HPAIV, their future movements could be predicted and appropriate preventive measures could be introduced to stop the virus transmission from wild to domestic birds and humans.
Once incorporated into monitoring programmes, together with other conventional methods for the investigation of the ecology and epidemiology of an HPAIV infection, this approach will significantly enrich the knowledge base for tracking and predicting outbreaks of this devastating disease. Moreover, the technology for non-invasive monitoring of both, the virus transmission and migratory pathway of wild birds, could be easily transferred to other diseases, where movement of wild animals and/or disease vectors play a role in disease transmission. Specific diseases that are of importance are foot-and-mouth disease, rabies, vector borne diseases and others.
Both nuclear techniques are quick and effective forensic tools in the fight against HPAI, and the training courses organized by the IAEA are essential in building Member States' capacity to control and prevent this dangerous disease.