DETECTION OF HEPATITIS-A VIRUS IN OYSTERS

A digoxigenin-labelled RNA probe with a sensitivity of 800 50% tissue culture infectious dose (TCID50) was used to detect Hepatitis A Virus (HAV) in oysters. We studied the influence of extraction methodology o n riboprobe detection. Oyster samples obtained by four methods of extr action and extraction-concentration were spiked with HAV (CF53 strain) . There was no correlation between protein concentration and turbidity of samples, and anti-digoxigenin antibodies showed a non specific rea ction. Background noise was independent of protein concentration and d isappeared when HAV RNA isolation by phenol/chloroform extraction was introduced, but HAV RNA could not be detected by this technique. In th e presence of Acid Guanidinium Thiocyanate (AGT), RNA from HAV suspens ion was detected following phenolic extraction with a detection thresh old of 8. 10(4) TCID50 Of spotted virus. HAV detection in oyster extra ct by a digoxigenin-labelled riboprobe appeared useful in shellfish vi rology, at least for a primary screening of samples.