OIE validation template: level 3 Technology transfer and reproducibility description of training requirements, standardization complete description of rproducibility study (serum panels, logistics, laboratory selection, analysis, performance requirements) FMD specific performance criteria Immunity differentiation between infection and vaccination detection of infection in vaccinated animals carrier status Scope of validation cattle, swine, small ruminants, etc. virus-type geographical area Epidemiology "absence of infection/disease" impossible to prove detectable levels of (design; threshold) prevalence; e.g. 0.2% among-herds; 5% within-herds ("virus circulation") established and circulating(?) infection at prevalence below design prevalence in vaccinated populations – how low? 5% in infected/vaccinated animals? Herd-level sensitivity (HSe) increases with prevalence Illustration Assume 80% sensitivity of NSP ELISA in carrier cattle and 99% specificity for vaccinated, non-infected cattle For Herd size 1000; 5% within-herd prevalence; sample size 58 We obtain herd-level specificity (HSp) = 55.8%; HSe = 95% But HSe = 66% and 47% for 1% and 0.1% prevalence, respectively Discussion We need reliable assay validation data (diagnostic Se and Sp) cattle, swine, small ruminants (and others) goals must be defined We need consensus about the levels of "design prevalence" for vaccinated populations Fixed values for required sensitivity and specificity are not useful
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