ABSTRACT
Aerosol transmission is an important disease transmission route and has been especially pertinent to hospital and biosafety laboratories during the SARS-CoV-2 pandemic. The thermal resistance of airborne SARS-CoV-2 is lower than that of Bacillus subtilis spores, which are often used to test the effectiveness of SARS-CoV-2 and other pathogen disinfection methods. Herein, we propose a new method to test the disinfection ability of a flowing air disinfector (a digital electromagnetic induction air heater) using B. subtilis spores. The study provides an alternative air disinfection test method. The new test system combined an aerosol generator and a respiratory filter designed in-house and could effectively recover spores on the filter membrane at the air outlet after passing through the flowing air disinfector. The total number of bacterial spores used in the test was within the range of 5 × 105–5 × 106 colony-forming units (CFUs) specified in the technical standard for disinfection. The calculation was based on the calculation method in Air Disinfection Effect Appraisal Test in Technical Standard for Disinfection (2002 Edition). At an air speed of 3.5 m/s, we used a digital electromagnetic induction air heater to disinfect flowing air containing 4.100 × 106 CFUs of B. subtilis spores and determined that the minimum disinfection temperature was 350 °C for a killing rate of 99.99%. At 400 °C, additional experiments using higher spore concentrations (4.700 × 106 ± 1.871 × 105 CFU) and a higher airspeed (4 m/s) showed that the killing rate remained>99.99%. B. subtilis spores, as a biological indicator for testing the efficiency of dry-heat sterilization, were killed by the high temperatures used in this system. The proposed method used to test the flowing air disinfector is simple, stable, and effective. This study provides a reference for the development of test systems that can assess the disinfection ability of flowing air disinfectors.
ABSTRACT
Numerous serological detection kits are being rapidly developed and approved for screening and diagnosing suspected coronavirus disease 2019 (COVID-19) cases. However, cross-reactivity between pre-existing antibodies against other coronaviruses and the captured antigens in these kits can affect detection accuracy, emphasizing the necessity for identifying highly specific antigen fragments for antibody detection. Thus, we performed a conservation and specificity analysis of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N) protein. We also integrated various B-cell epitope prediction methods to obtain possible dominant epitope regions for the N protein, analyzed the differences in serological antibody levels for different epitopes using ELISA, and identified N protein epitopes for IgG and IgM with high-specificity. The SARS-CoV-2 N protein showed low mutation rates and shared the highest amino acid similarity with SARS-CoV; however, it differed substantially from other coronaviruses. Tests targeting the SARS-CoV-2 N protein produce strong positive results in patients recovering from SARS-CoV. The N18-39 and N183-197 epitopes for IgG and IgM detection, respectively, can effectively overcome cross-reactivity, and even exhibit good specificity between SARS-CoV-2 and SARS-CoV. The antibody levels detected with these were consistent with those detected using the complete N protein. These findings provide a basis for serological diagnosis and determining the kinetics of SARS-CoV-2 antibody detection in patients.
ABSTRACT
Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection has spread rapidly across the world and become an international public health emergency. Both SARS-CoV-2 and SARS-CoV belong to subfamily Coronavirinae in the family Coronaviridae of the order Nidovirales and they are classified as the SARS-like species while belong to different cluster. Besides, viral structure, epidemiology characteristics and pathological characteristics are also different. We present a comprehensive survey of the latest coronavirus-SARS-CoV-2-from investigating its origin and evolution alongside SARS-CoV. Meanwhile, pathogenesis, cardiovascular disease in COVID-19 patients, myocardial injury and venous thromboembolism induced by SARS-CoV-2 as well as the treatment methods are summarized in this review.