Appendix 3 Diagnostic reagent banks for FMD Position paper of the EUFMD Research Group – October 2004 Introduction The traditional main role of laboratories specialised on foreign animal diseases has been the rapid confirmation of new outbreaks. In future, testing for proving freedom of disease and testing as a basis for movement, slaughter and trade certificates will become more and more important. New tests allow the detection of infected animals in a vaccinated population. However, in “peace times” few samples are tested for FMD. In order to meet the sudden demand for rapid mass testing in an emergency, reagent banks are required in addition to the already existing vaccine banks. The Council Directive on Community measures for the control of foot-and-mouth disease requires serological tests in all cases, where a diagnosis based on clinical signs would not be sufficient to detect the disease fast enough and with the necessary degree of confidence. As a general rule, when the presence of foot-and-mouth disease is suspected in the absence of clinical signs, a sampling protocol suitable to detect 5% prevalence with at least 95% level of confidence must be used. This means about 60 samples per stable and, in areas of high animal densities, ten or even hundred thousands of samples in total. Many of these tests will have to be performed under an enormous time pressure. If vaccination is used, testing for infection with FMDV, either by an assay for antibodies against non-structural proteins of the FMDV, or by another approved method, shall meet the statistical condition mentioned above. However, it might even be decided to test samples taken from all vaccinated animals of susceptible species and their non-vaccinated offspring in all herds in the vaccination zone. Since a vaccine bank typically contains between one and five million cattle doses, this could mean as many tests. A look at the 2001 FMD epidemic confirms that we have to be prepared to test hundred thousands or even millions of samples. In the UK, in order to prove freedom of FMD, 3 million samples had to be tested with a throughput of 200 000 samples a week. This became possible after the solid-phasecompetition ELISA (SPCE) had been established in five additional laboratories. Because there was and still is no validated commercial test kit available, a considerable lead-in time was required until the full serological capacity was reached. In the Netherlands, the laboratory diagnosis of animal diseases is centralized at ID Lelystad, (now CIDC-Lelystad). Thus, in contrast to many other FMD institutes, ID Lelystad had the experience, equipment and staff for large scale serological screening. About 200 000 sera were tested by a mabbased competition-ELISA. It´s specificity was not fully satisfactory, but the necessary retesting by VNT could be done on the site. In retrospect, Europe was lucky that the countries that had to do most of the testing also had large, well staffed and experienced laboratories. In many other countries, there would have been a much longer delay until the necessary throughput could have been achieved. The strategic problems of FMD serology The first strategic problem with FMD serology is, that in “peace times” there is almost no market for FMD test kits in Europe because the number of samples to be tested is small and these testing is done by a few specialized laboratories using in-house methods. This situation is complicated by the fact that there are 7 serotypes which all require their own test, if “anti-structural” antibodies have to be determined. In addition, even some of the many subtypes may require their own special tests. As a consequence, there is limited incentive for the industry to develop and keep ready test kits that could be used in laboratories not specialized on FMD. The second strategic problem is, that because of the security concerns, the complication caused by the many different subtypes and the necessity to check doubtful results by VNT using infectious virus, the small number of samples regularly examined are mostly tested in relatively small, specialized laboratories, which often concentrate on research, not on high throughput serology. In a crisis, however, FMD laboratories would be expected to quickly scale up their serological screening capacity to levels reaching or exceeding the whole serological capacity of all the countries veterinary laboratories combined. This is a problem especially for countries with a decentralized laboratory structure like Germany, where almost all the routine work is preformed by regional (state) diagnostic laboratories, while the national reference lab belongs to the Federal Research Center. Since the regional laboratories often already have the staff, the experience, the rooms and the sample handling robots for mass serology, enabling them to perform mass serology also for FMD is much more
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