COLLABORATIVE EVALUATION OF A METHOD FOR THE DETECTION OF NORWALK VIRUS IN SHELLFISH TISSUES BY PCR

A multicenter, collaborative trial mas performed to evaluate the relia bility and reproducibility of a previously described method for the de tection of Norwalk virus in shellfish tissues with the PCR (R. L. Atma r, F. H. Neill, J. L. Romalde, F. Le Guyader, C. M. Woodley, T. G. Met calf, and M. K. Estes, Appl. Environ. Microbiol. 61:3014-3018, 1995). Virus was added to the stomachs and hepatopancreatic tissues of oyster s or hard-shell clams in the control laboratory, the samples were ship ped to the participating laboratories, and viral nucleic acids mere ex tracted and then detected by reverse transcription-PCR. The sensitivit y and specificity of the assay were 85 and 91%, respectively, when res ults mere determined by visual inspection of ethidium bromide-stained agarose gels; the test sensitivity and specificity improved to 87 and 100%, respectively, after confirmation by hybridization with a digoxig enin-labeled, virus-specific probe. We have demonstrated that this met hod can be implemented successfully by several laboratories to detect Norwalk virus in shellfish tissues.