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The Early and Rapid Diagnosis of Emerging Diseases (focus on avian influenza)
Closed for proposals
Project Type
Project Code
D32025CRP
1383Approved Date
Status
Start Date
Expected End Date
Completed Date
22 October 2012Description
The IAEA is supporting Member States in their efforts to control diseases of importance. This, amongst others, involves the development, evaluation and validation of the appropriate nuclear and nuclear related technologies and the harmonization of protocols and procedures. Technical advice is therefore given to Member States (or any other party) as to the diagnosis of a disease, the best "fitness for purpose" tools and quality assured procedures, including vaccines, to use in close collaboration and consultation with experts in the field. In the case of avian influenza it is important for the rapid and differential diagnosis to classify isolates as highly pathogenic or not in order to activate appropriate control measures - this is seen as the bottleneck activity for most developing countries.
Highly pathogenic avian influenza (HPAI) now commonly known as “bird flu” is caused by the infection with some strains of Influenza A virus. The different strains of this virus are classified into subtypes on the basis of their two external proteins named haemagglutinin (H) and neuraminidase (N). Techniques that are implemented for the diagnosis of avian influenza aimed at demonstrating first the presence of the causal virus in pathological samples and then at assessing it’s pathogenicity. Indeed, only some strains of avian influenza, highly pathogenic (HPAI), are at the origin of outbreaks and: they belong to the H1, H5 or H7 subtypes. The current avian influenza outbreak which started in Asia in 2004 is caused by a virus of H5 subtype. In addition, this virus was further characterised as of the N1 subtype which is able to cause deaths in humans.
Usually, from the pathological sample, the virus is first isolated in embryonated fowl eggs which takes 4-7 days to complete. Then the subtype of the isolated virus is identified by a battery of specific antibodies raised against the different H (H1 to H15) and N (N1 to N9) proteins. This way of identification is carried out only in specialized laboratories. To confirm a subtype’s pathogenicity, the isolate is then inoculated into 4-8 week-old susceptible chickens. For the World Organisation for Animal Health (OIE), strains are considered to be highly pathogenic if they cause more than 75% mortality in inoculated chickens within 10 days. An alternative way to demonstrate the presence, and characterize the influenza virus in the pathological samples, is the specific detection of its RNA by nucleic acid amplification techniques (PCR and PCR sequencing, using either fluorescent or isotopic [P32, P33 or S35] markers). This molecular approach takes 1-2 days to complete. Furthermore, it is foreseen that this technology could be applied as early warning tools.
Objectives
Develop, evaluate and validate early and rapid detection technologies to provide Member States (MS) with the capacity to detect, monitor, contain and control transboundary animal diseases (TADs). The CRP will support the build-up of competence in the use of modern biotechnology, including molecular and serological methods, to provide systems and technologies to be used in the field as well as in laboratories. A major target for diagnostic systems will be the highly pathogenic avian influenza (HPAI) viruses, but such systems will be pertinent to all other TADs since the technologies addressed in this CRP will form part of an early response diagnostic capability platform.
Specific objectives
Agreement to examine specific diagnostic systems for early and rapid diagnosis of avian influenza.
Determine the potential use of stable isotope analysis in tracing migratory pathways of wild water fowl.
Develop SOP for DNA barcoding for differentiation of WWF species using faecal samples.
Develop SOPs for detection and quantitative evaluation of the AIV in natural water reservoirs.
Develop SOPs for detection and typing of the AIV in WWF using faecal samples.
Improve the existing isoscapes for dD and other essential isotopes, especially in the regions of Asia and Africa.
Widening the scope of activities within the CRP network.
Impact
The CRP has an impact in several aspects of the disease control chain, as follows:
a) Harmonized diagnostic techniques are contributing towards better accuracy and reliability of the established diagnosis at international level.
b) Multiple test platforms are contributing towards clarification of borderline or ambiguous test results.
Both a) and b) support early and rapid diagnosis of infectious diseases, enabling timely enforcement of control and/or eradication measures!
c) On-the-spot diagnostic tools are easy, price convenient and reliable. They do not require major laboratory resources, neither highly trained staff. They are additionally easy to transport and simple to manipulate, which enables for establishing of initial diagnosis directly in the field with direct transfer of the information to the competent veterinary authority.
Adapting recognized diagnostic technologies for testing of faecal samples enables for non-invasive and more extensive disease surveillance and obtaining timely and relevant epidemiological information without even capturing the birds!
d) Stable isotopes reflect the food and water intake in animals (including birds). As individual SI have different spatial pattern, the feeding/drinking of animals at different geographical regions will generate different SI signature in the tissues (especially in the feathers as metabolically inert tissues)! Thus, this technology may replace conventional labelling or installing satellite transmitters, because they can be used in extremely small portion of the population and are dependent on recapture or signal strength! Additionally, if this technology is proven successful, combination of different isotopes may be used for tracing short range migrants, such as foxes, wolfs, wild boars, rodents and thus contribute towards understanding the wildlife epidemiology of numerous animal diseases (FMD, ASF, CSF), including zoonoses, (rabies),
The multiple and harmonized diagnostic platforms, as well as on-the-spot diagnostic tools (achievements of this project) are currently used in several TC projects of APH/NAFA, such as BUL/5/002, BOH/5/001, MLI/5/025, RER/5/015, RER/5/016 and others. They will also be used in the future TC projects.
Quantifiable result of the approach demonstrated in this project is the continuously increasing number of accredited laboratories using the demonstrated techniques and continuously increasing number of disease reporting to OIE (in terms of number of Member States reporting diseases and the number of diseases reported).
Initial results of the stable isotope investigations obtained in this project (mentioned above) are planned to be extended towards understanding their wider applicability, not only in long range migrants (wild migratory birds), but also in short range migrants, such as wild carnivores and ruminants and wild boars. Tracing these animals will largely contribute towards understanding their epidemiological role as carriers of animal diseases, including those with zoonotic impact.
Relevance
The CRP is relevant because it affects much wider panel of diseases, than avian influenza and New Castle disease. The above mentioned platforms, upon proper validation may be applied in numerous diseases affecting animal and humans.
Stable isotope analyses, is relatively new scientific discipline which (in the animal production and health field) gained on interest due to capacity to trace back migrations (and thus pathogens also). However, it seems that this interest will rise in the future, due to extended use of SI in short range migrants.