NR AWKD
AU Meloni,D.; Nappi,R.; Di Vietro,D.; Manzardo,E.; Mazza,M.; Ingravalle,F.; Bozzetta,E.
TI Performance of BSE rapid tests on autolytic brain stem: the "in field" Italian experience
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions DIA-36
PT Konferenz-Poster
AB Routine rapid testing has highlighted some major problems related to in field BSE rapid tests performance in comparison with the EU evaluation. Two of the most significative ones are the number of "initially reactive" samples (samples with positive results at first examination resulting negative under re-testing) and false positive results related to autolytic samples. This aspect is pivotal for Italian BSE active surveillance in risk populations, because the collection of fallen stock is not carried out on a daily basis or because isolated or mountain farms are not easily accessible. Thus a robust test, able to perform on samples in autolytic conditions is needed. To evaluate the robustness of the rapid test systems in use in Italy, we selected 450 autolyzed brain stem samples from bovine older then 24 months. According to the degree of autolysis, assessed and scored using a ranking system from 1 to 3, the samples were divided in 3 categories (low, medium and high autolysis). Samples were dissected in 3 pieces (or in high autolyzed tissue selected from the same tissue mass) randomly assigned to the rapid test systems in use in Italy: Biorad TeSeE, Enfer TSE version 2.0, Abbott and Prionics check LIA. Each aliquot was tested following standard operating procedures (SOPs) prepared according to the manufacturers instructions. The 95% confidence limits for specificity was calculated using the STATA 9 software. Specificity resulted 100% (IC95% 97,57%-100%) for the 3 tests for all categories. Biorad TeSeE identified correctly the samples of all the 3 categories at first examination, Enfer TSE gave 2 initially reactive samples from category 1 (1.3%) and 1 from each of the other two (0.6%), while Prionics check LIA gave one initial reactive sample from the category 1 (0.6%) and could correctly classify the others. Our results show that the 3 tests can be applied even on severe autolytic samples without giving false positive results.
AD CEA-Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Turin, Italy. E-mail: Daniela.meloni@izsto.it
SP englisch
PO Italien