Early Detection of Transboundary Animal Diseases (TADs) to Facilitate Prevention and Control through a Veterinary Diagnostic Laboratory Network (VETLAB Network)

Summary

The project aims to establish and / or integrate a panel of standard procedures and necessary quality control materials for establishment of regional and global harmonization of nuclear and nuclear related diagnostic techniques for early detection of animal and zoonotic pathogens, using standardized and internationally recognized principles. It additionally aims to establish multi pathogen detection platforms in order to enable for differential diagnosis of syndromic diseases using a single testing run.

Background and Situation Analysis

Animal diseases are one of the major threats for the animal production and the overall agricultural sector. Additionally, approximately 70% of the emerging diseases of humans have zoonotic potential and are therefore posing a public health threat.

The technology development and the consequent (advanced) understanding of the disease aetiology, pathogenesis and epidemiology have resulted in significant reduction (bacterial diarrhoeas, bacterial respiratory diseases, clostridial infections, anthrax and others) or eradication (smallpox, rinderpest) of some of the “conventional” diseases. However, the modern trends in global migration and trade, urbanization, intensification of the animal production, as well as the recent climate changes are continuously stressing the ecosystems, creating a favourable environment for re-appearance of the “conventional” diseases, as well as the appearance of diseases with much more complex ecology and epidemiology.

Recent examples of the rapid spread of well-known devastating diseases, such as the Peste des Petits Ruminants (PPR) or the African swine fever (ASF), avian influenza (AI), as well as the appearance of re-emerging diseases, such as the viral haemorrhagic fevers (ebola, Cremian-Congo haemorrhagic fever), West Nile fever, Nipah fever and others are a clear indicator of the need of novel approaches in the early detection, control and / or eradication of the infectious diseases. This especially because these diseases have complex epidemiology, with involvement of asymptomatic wildlife carriers (ticks in ASF, wild birds in AI, bats in Ebola and other haemorrhagic diseases) and / or domestic carriers. Consequently, the control of these diseases requires complex responses, involvement of multiple sectors (wildlife groups, ornithologists, entomologists, public health authorities etc.), qualified epidemiological teams for analysis and decision making, as well as a compact coordination system at the head veterinary office, ready to coordinate the overall actions. The technologies developed through the project are based on the nuclear related serological and molecular assays. The CRP aims to evaluate and establish multi pathogen diagnostic techniques, targeted towards syndromic disease panels. This approach offers several advantages, such as easier reference for the field veterinary services to clinically direct the use of diagnostic procedures in the laboratories, as well as the possibility to screen for differential diagnostric answers in one testing run. However, for the positive reactors additional diagnostic analyses will be performed in order to differentiate the pathogen within its phylogenetic species, such as Sanger sequencing).

The laboratory component of the disease control has a critical role in the early detection, monitoring and control of the infectious diseases. The above mentioned disease evolvements, as well as the technological developments at global level (increased travel, trade and information exchange), have clearly established multiple demands towards the updating of the positions, functions and the responsibilities of national and regional laboratory networks in the disease control chain. This primarily concerns the establishment of clear responsibility lines within the laboratory structure, clear and transparent procedures for sustainable equipment maintenance (priority on measurement instruments) and the use of internationally accepted and harmonized diagnostic techniques. The national, regional and global animal health authorities have responded to these demands at multiple levels. The International Standard Organization (ISO), at the beginning of 2000s’ has issued the ISO 17025 standard (Link 1), which practically is a successor of the European EN 45001 and the UK UKAS M10 standards. The standard requires a clear definition of the laboratory management structure, equipment maintenance and the use of recognized (validated) tests according to pre-defined procedures. It additionally assumes continuous supervision of the quality control and quality assurance (QC/QA) system, clearly defined improvement targets (referring to the overall QA system and especially to the use of improved testing procedures), and anticipates periodical independent audits by authorized bodies, thus enabling laboratories to be accredited, rather than being certified or registered under the ISO 17025 standard.

In order to comply with the international standards, the World Organization for Animal Health (OIE –Link 2) has developed specific animal health standards for management of veterinary diagnostic laboratories (Link 3), quality management in veterinary testing laboratories (Link 4), a standard on the principles and methods of validation of diagnostic assays (Link 5), as well as specific requirements for diagnosis of individual animal and zoonotic diseases (The Manual of Diagnostic Tests and Vaccines for Terrestrial Animals – Link 6). Additionally, the OIE has outlined the rules for the functions and responsibilities of the OIE reference laboratories (Link 7) and Collaborating Centres (Link 8) and initiates / participates in the development of international diagnostic disease control networks, together with the other international organizations, such as the Food and Agricultural Organization of the United Nations-FAO (Link 9) and the World Health Organization-WHO (Link 10). Examples of such networks are the OFFLU Network (Link 11), the FAO-OIE-WHO Tripartite Collaboration (Link 12) and the Crisis Management Centre – Animal Health-CMC-AH (Link 13). The QA and the networking concepts of the international organizations are widely used in many developed countries and regions throughout the world, such as the United States Department of Agriculture (USDA) through the National Animal Health Laboratory Network-NAHLN (Link 14), Australian Animal Health Laboratories-AAHL (Link 15) and the European Union (Link 16). These networks are anticipating the establishment of various levels of assignments for all designated laboratories in the disease detection and control system giving them different roles in the overall diseases surveillance/control chain. The reference laboratories are the ones which design, validate and implement diagnostic assays, whereas the official laboratories are using the already developed assays for diagnostic purposes. Additionally, the reference laboratories are usually assigned for confirmation or advanced classification of the pathogens detected in the official laboratories, as well as for maintaining the harmonization at national, regional or international level.

The developing Member States (MS) are upgrading their laboratories predominantly by themselves or through their participation in the programmes of the international organizations. Some of the MS are participating in already established regional or international networks, however not many of them as permanent members. Additionally, most of the existing networks are not including QA / QC issues in their programmes. Consequently, the implementation of the international standards applicable for animal health cannot be continuously supported and appropriately maintained. The Veterinary Laboratory Network (VETLAB Network), a Joint FAO/IAEA Network currently integrates 32 African and 17 Asian MS which are dedicated to share knowledge and experience and support each other during the implementation of international standards, routine diagnostic procedures, sharing diagnostic approaches for specific disease outbreaks, thus facilitating the emergency preparedness and response to animal health emergencies. The concept of networking has proven its fitness for purpose during the rinderpest eradication campaign. Nowadays, this concept has resulted with great successes in some of the MS, where the diagnostic laboratories have received accreditation for the ISO 17025 standard. Additionally, several other laboratories in this network are in advanced phases of implementation of the standard and expect soon accreditation.

When transboundary disease events are likely to appear, or have already appeared, regional laboratory preparedness is critical for the implementation of the complex, multi-sectorial disease responses. Therefore, the maintenance, strengthening and upgrade of the laboratory networks is of utmost importance for the planning and the start-up of proper contingency plans aimed to prevent and / or control the currently threatening diseases.

The VETLAB Network is a concept for the establishment of a unique regional/interregional communication and activity skeleton which enables for sustainable functioning and upgrade of the laboratories under internationally recognized principles.

Nuclear Component

Nuclear and nuclear related techniques have played and still play an important role in this system. The initial development of the core diagnostic technologies has been based on purely nuclear methods. The Enzyme Linked Immunosorbent Assay (ELISA) which is a technology used for detection of the antigen (parts of the pathogens) or the antibodies induced by specific pathogens in the body of the host has been developed using isotopic labelling and consequent measurement of the radioactivity of the isotopically labelled ligands. The Polymerase Chain Reaction (PCR) and the cyclic sequencing have their origin also in purely nuclear techniques, where individual nucleic bases were labelled using radioactive isotopes, followed by transferring the signal from agarose gel onto a photographic film. Although in many cases, due to safety reasons, the isotopic labelling has been replaced by enzymes (ELISA) or fluorophores (PCR), it has still major advantages over alternative labelling systems, as it does not affects the chemistry of the reactions and are therefore considered as reference standards. In addition, radiolabelling (P32/S35/Met-S35) of proteins and nucleic acid allows us to identify single copies within a million similar copies - resulting in high specificity and sensitivity needed to identify a pathogen before the onset of a disease. Nuclear techniques are also used in tracing animal migrations through the measurement of stable isotopes in the metabolically inert tissues. The approach gives significant advantages over the conventional animal labelling (capturing, ringing, installing GIS devices and later on re-capturing), as it opens the possibility for establishment non-invasive solutions for tracing migrations of animals, which may carry and transmit transboundary animal and/or zoonotic disease. Non-invasive approaches for disease are increasingly gaining on importance considering the animal welfare issues as well as the wildlife conservation.

The reference materials which will be established under this CRP will be inactivated and preserved using gamma rays. The irradiation dose will be matched to the antigenic and molecular properties, in order to determine the safe limits for inactivation of unspecific pathogens and contaminants contained in the standard reference materials, without losing their diagnostic properties.

Specific Research Objectives

  • To develop a set of internationally acceptable standards for the serological diagnostic techniques for priority diseases among the partners of the VETLAB Network.
  • To develop a set of internationally acceptable standards for the molecular diagnostic techniques for priority diseases among the partners of the VETLAB Network.
  • To development a procedures for simultaneous detection of multiple pathogens (multi-pathogen detection panels).
  • To develop a procedure for easy access, free-of-charge genetic sequencing services for pathogens of the priority diseases among the partners of the VETLAB Network.
  • To establish an information platform for integrated information collection, geo-visualization, analysis and decision making.

Expected Research Outcomes

Well harmonized regional/intra-regional laboratory network for detection and differentiation of animal and zoonotic diseases established / upgraded.

Expected Research Outputs

  • Serological techniques in participating laboratories of the VETLAB Network harmonized.
  • Molecular techniques in participating laboratories of the VETLAB Network harmonized.
  • Multi pathogen detection platforms established.
  • Protocols and access to free-of-charge sequencing protocols the VETLAB Network established.
  • Information platform integrating all relevant information related to laboratory testing and traceability of the final results established.