Tuyển tập các báo cáo nghiên cứu về bệnh học thý y được đăng trên tạp chí Acta Veterinaria Scandinavica cung cấp cho các bạn kiến thức về bệnh thú yđề tài: Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera. | Jacobson et al. Acta Veterinaria Scandinavica 2011 53 23 http content 53 1 23 AVS ACTAVETERINARIA Scojftov cc ia SCANDINAVICA RESEARCH Open Access Evaluation of a blocking ELISA for the detection of antibodies against Lawsonia intracellularis in pig sera Magdalena Jacobson1 Per Wallgren1 2 Ann Nordengrahn3 Malik Merza3 and Ulf Emanuelson1 Abstract Background Lawsonia intracellularis is a common cause of chronic diarrhoea and poor performance in young growing pigs. Diagnosis of this obligate intracellular bacterium is based on the demonstration of the microbe or microbial DNA in tissue specimens or faecal samples or the demonstration of L. intracellularis-specific antibodies in sera. The aim of the present study was to evaluate a blocking ELISA in the detection of serum antibodies to L. intracellularis by comparison to the previously widely used immunofluorescent antibody test IFAT . Methods Sera were collected from 176 pigs aged 8-12 weeks originating from 24 herds with or without problems with diarrhoea and poor performance in young growing pigs. Sera were analyzed by the blocking ELISA and by IFAT. Bayesian modelling techniques were used to account for the absence of a gold standard test and the results of the blocking ELISA was modelled against the IFAT test with a 2 dependent tests 2 populations no gold standard model. Results At the finally selected cut-off value of percent inhibition PI 35 the diagnostic sensitivity of the blocking ELISA was 72 and the diagnostic specificity was 93 . The positive predictive value was and the negative predictive value was at the observed prevalence of . Conclusion The sensitivity and specificity as evaluated by Bayesian statistic techniques differed from that previously reported. Properties of diagnostic tests may well vary between countries laboratories and among populations of animals. In the absence of a true gold standard the importance of validating new methods by appropriate .
