Evaluation Of A Test Method To Detect Hepatitis A Virus In Salted Shellfish

Contaminated salted shellfish were a suspected cause of the 2019 hepatitis A outbreak in Korea; however, no virus was detected in the shellfish by the virus detection tests used. In this study, we investigated the shortcomings of these detection tests for identifying hepatitis A virus in salted shellfish to serve as a guide for improvement of these tests. Salted shellfish were washed and desalted before collecting the mid-guts for testing. For verification of the method, the mid-guts were first inoculated with norovirus and then RT-qPCR was performed to determine the presence of norovirus genes. The norovirus gene was amplified normally along with an internal positive control; however, when the nucleic acid was extracted to be concentrated, gene amplification was inhibited. Since NaCl was the suspected contaminant, RT-qPCR was then performed on samples that had been desalinated for 2 days, and hepatitis A virus genes were successfully detected. Gene amplification enabled analyzing the relationship between patients in the outbreak and the distributed salted shellfish. To detect viral contamination in salted and fermented specimens such as salted shellfish, it is imperative to extract the mid-gut intestinal tract and remove any PCR inhibitors (e.g., excess salt). In this study, desalting salted shellfish using sterile distilled water before harvesting the mid-gut was effective in facilitating hepatitis A detection. Development of future test methods requires accurately determining the effect of PCR inhibitors through the incorporation of an IPC in genetic detection tests.