Viral Inactivation with Emphasis on SARS-CoV-2 Using Physical and Chemical Disinfectants.

BACKGROUND: Recently, an outbreak of a novel human coronavirus SARS-CoV-2 has become a world health concern leading to severe respiratory tract infections in humans. Virus transmission occurs through person-to-person contact, respiratory droplets, and contaminated hands or surfaces. Accordingly, we aim at reviewing the literature on all information available about the persistence of coronaviruses, including human and animal coronaviruses, on inanimate surfaces and inactivation strategies with biocides employed for chemical and physical disinfection. METHOD: A comprehensive search was systematically conducted in main databases from 1998 to 2020 to identify various viral disinfectants associated with HCoV and methods for control and prevention of this newly emerged virus. RESULTS: The analysis of 62 studies shows that human coronaviruses such as severe acute respiratory syndrome (SARS) coronavirus, Middle East respiratory syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV), canine coronavirus (CCV), transmissible gastroenteritis virus (TGEV), and mouse hepatitis virus (MHV) can be efficiently inactivated by physical and chemical disinfectants at different concentrations (70, 80, 85, and 95%) of 2-propanol (70 and 80%) in less than or equal to 60 s and 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Additionally, glutaraldehyde (0.5-2%), formaldehyde (0.7-1%), and povidone-iodine (0.1-0.75%) could readily inactivate coronaviruses. Moreover, dry heat at 56°C, ultraviolet light dose of 0.2 to 140 J/cm2, and gamma irradiation could effectively inactivate coronavirus. The WHO recommends the use of 0.1% sodium hypochlorite solution or an ethanol-based disinfectant with an ethanol concentration between 62% and 71%. CONCLUSION: The results of the present study can help researchers, policymakers, health decision makers, and people perceive and take the correct measures to control and prevent further transmission of COVID-19. Prevention and decontamination will be the main ways to stop the ongoing outbreak of COVID-19.

Canine coronavirus inactivation with physical and chemical agents.

Canine coronavirus (CCoV) is responsible for mild or moderate enteritis in puppies. The virus is highly contagious and avoiding contact with infected dogs and their excretions is the only way to ensure disease prevention. Since no studies have yet focused on the sensitivity of CCoV to chemical biocides the present investigation examined the efficiency of physical and chemical methods of viral inactivation. CCoV infectivity was stable at +56 degrees C for up to 30 min, but tended to decrease rapidly at +65 degrees C and +75 degrees C. Germicidal ultra-violet (UV-C) light exposure demonstrated no significant effects on virus inactivation for up to 3 days. CCoV was observed to be more stable at pH 6.0-6.5 while extreme acidic conditions inactivated the virus. Two tested aldehydes inactivated the virus but their action was temperature- and time-dependent. The methods for CCoV inactivation could be applied as animal models to study human coronavirus infection, reducing the risk of accidental exposure of researchers to pathogens during routine laboratory procedures.

Indomethacin has a potent antiviral activity against SARS coronavirus.

UNLABELLED: Severe acute respiratory syndrome (SARS) is a newly emerging, highly transmissible and fatal disease caused by a previously unknown coronavirus (SARS-CoV). Existing in non-identified animal reservoirs, SARS-CoV continues to represent a threat to humans because there is no effective specific antiviral therapy for coronavirus infections. OBJECTIVES: Starting from the observation that cyclopentenone cyclooxygenase (COX) metabolites are active against several RNA viruses, we investigated the effect of the COX inhibitor indomethacin on coronavirus replication. METHODS: Work involving infectious SARS-CoV was performed in biosafety level 3 facilities. SARS-CoV was grown in monkey VERO cells and human lung epithelial A549 cells, while canine coronavirus (CCoV) was grown in A72 canine cells. Antiviral activity was analysed by determining infective virus titres by TCID50, viral RNA synthesis by Northern blot analysis and real-time RT-PCR, and viral protein synthesis by SDS-PAGE analysis after 35S-methionine-labelling. Antiviral efficacy in vivo was determined by evaluating virus titres in CCoV-infected dogs treated orally with 1 mg/kg body weight indomethacin (INDO). RESULTS: Unexpectedly, we found that INDO has a potent direct antiviral activity against the coronaviruses SARS-CoV and CCoV. INDO does not affect coronavirus binding or entry into host cells, but acts by blocking viral RNA synthesis at cytoprotective doses. This effect is independent of cyclooxygenase inhibition. INDO's potent antiviral activity (>1,000-fold reduction in virus yield) was confirmed in vivo in CCoV-infected dogs. CONCLUSIONS: The results identify INDO as a potent inhibitor of coronavirus replication and suggest that, having both anti-inflammatory and antiviral activity, INDO could be beneficial in SARS therapy.

Action of disinfectants on canine coronavirus replication in vitro.

Canine coronavirus (CCoV) is responsible for enteric disease in pups. Infected dogs generally have a rapid recovery, so the virus is highly contagious and the spread of infection is difficult to control. Chemical disinfectants have been widely used in human disease-control programmes to prevent viral infectious diseases from spreading, but to date, there are no studies in the literature on the sensitivity of CCoV to chemical biocides. The present study investigated the sensitivity of CCoV to disinfectants currently used for prophylaxis in kennel and dog breeding locations. The effects of three agents: alkyl-dimethyl-benzyl-ammonium chloride, benzalkonium chloride and didecyl-dimethyl-ammonium chloride, on the infectivity titre of CCoV in A72 cell lines, were studied at different concentrations. Although they may regard a small number of agents, the findings showed that the sensitivity of CCoV to disinfectants varies and the differences are dose correlated. In general, virus inactivation implies a permanent loss of infectivity which can be evaluated in suspensions and hand disinfection tests.