Inactivating porcine coronavirus before nuclei acid isolation with the temperature higher than 56 °C damages its genome integrity seriously

2019-Novel Coronavirus (2019-nCoV) is the pathogen of Corona Virus Disease 2019. Nucleic acid detection of 2019-nCoV is one of the key indicators for clinical diagnosis. However, the positive rate is only 30-50%. Currently, fluorescent quantitative RT-PCR technology is mainly used to detect 2019-nCoV. According to "The Laboratory Technical Guidelines for Detection 2019-nCoV (Fourth Edition)" issued by National Health and Commission of China and "The Experts Consensus on Nucleic Acid Detection of 2019-nCoV" released by Chinese Society of Laboratory Medicine, the human samples must be placed under 56{degrees}C or higher to inactivate the viruses in order to keep the inspectors from virus infection before the nucleic acids were isolated as the template of qRT-PCR. In this study, we demonstrated that the virus inactivation treatment disrupts its genome integrity seriously when using porcine epidemic diarrhea virus (vaccine), a kind of coronavirus, as a model. Our results showed that only 50.11% of the detectable viral templates left after the inactivation of 56 {degrees}C for 30 minutes and only 3.36% left after the inactivation of 92 {degrees}C for 5 minutes when the samples were preserved by Hanks solution, one of an isotonic salt solutions currently suggested. However, the detectable templates of viral nucleic acids can be unchanged after the samples were incubated at 56 {degrees}C or higher if the samples were preserved with an optimized solution to protect the RNA from being disrupted. We therefore highly recommend to carry out systematic investigation on the impact of high temperature inactivation on the integrity of 2019-nCoV genome and develop a sample preservation solution to protect the detectable templates of 2019-nCoV nucleic acids from high temperature inactivation damage.