ELISA and the Joint FAO/IAEA Division: Accomplishments and opportunities

The enzyme linked immunosorbent assay (ELISA) is an inexpensive yet sensitive and specific tool in the diagnosis of livestock diseases. The use of the ELISA can be associated with many efforts at reducing the enormous wastage of animals caused by infectious diseases. The use of this technology in the developing countries was recommended in 1983 by a consultants meeting called by the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna. Since then, enormous resources have been committed towards the development and standardization of ELISA kits and their application, mostly in Africa, Asia and Latin America. The IAEA introduced training programmes, initiated regional research efforts, sponsored technical co-operation projects, provided ELISA readers and other equipment and dispatched experts/trainers to assist laboratories in developing countries. International standards for ELISA data expression and evaluation, reagent reference standards and an external quality assurance programme have been developed with assistance from consultants so that laboratories can meet minimal ELISA performance standards. Despite these efforts, the proper validation of ELISAs for application in some geographical areas is still difficult. Unique specificity problems occur because of unknown substances in sera of test animals. The application of ELISA in the field is difficult, and usually laboratories are required for the analysis of samples. Even in the laboratory the technique is easily 'abused', resulting in invalid data. Therefore, the ELISAs of the future that will be most effective in control and eradication of livestock diseases in developing countries should be simpler, more specific, less prone to error and portable for use in remote areas. They will probably consist of membrane based ELISA technologies accompanied by handheld portable touch screen computers for data management. Inexpensive means of identification of tested animals are becoming available - a necessity for disease status certification. A guarantee of disease free status of national herds will assuredly improve the economic conditions of developing countries in the context of the global trade opportunities. The challenge is to provide that guarantee through creative applications of improved ELISAs or their assay relatives. (author)