Numerous coronaviruses, first discovered in domestic poultry in the 1930s, cause respiratory, gastrointestinal, liver, and neurologic diseases in animals. Only 7 coronaviruses are known to cause disease in humans.
Four of the 7 coronaviruses most frequently cause symptoms of the ‘common cold’. Coronaviruses 229E and OC43 cause the common cold; the serotypes NL63 and HUK1 have also been associated with the common cold.
Rarely, severe lower respiratory tract infections, including pneumonia, can occur, primarily in infants, older people, and the immunocompromised.
Three of the 7 coronaviruses cause much more severe, and sometimes fatal, respiratory infections in humans than other coronaviruses and have caused major outbreaks of deadly pneumonia in the 21st century:
SARS-CoV2 (COVID-19) is a novel coronavirus identified as the cause of coronavirus disease 2019 (COVID-19) that began in Wuhan, China in late 2019 (hence the name) and spread worldwide.
MERS-CoV was identified in 2012 as the cause of Middle East respiratory syndrome (MERS).
SARS-CoV in 2003 as determined the cause of an outbreak of severe acute respiratory syndrome (SARS) that began in China near the end of 2002. The mortality rate of SARS appears to range from 6 to 55%.
These coronaviruses that cause severe respiratory infections are termed “zoonotic pathogens”, which begin in infected animals and are transmitted from animals to people. SARS-CoV2 has significant transmissibility from person-to-person – it is highly contagious.
The importance of Nitric Oxide (NO)
Nitric oxide (NO) is an important signaling molecule between cells and is involved in a wide range of processes. An antimicrobial activity of NO has been described for several bacteria and protozoa and for some viruses. Nitric oxide is not related to nitrous oxide (laughing gas) the anesthetic gas used for dental sedation.
Recent (2020) results demonstrated that Nitric Oxide specifically inhibits the replication cycle of SARS CoV, most probably during the early steps of infection, suggesting that the production of NO by iNOS results in an antiviral effect.
Nitic Oxide (NO) is produced in the nasal sinuses and is a natural disinfectant. Nasal breathing over mouth breathing promotes its effectiveness. The study shows that NO inhibits viral protein and RNA synthesis.
Furthermore, the study demonstrated that NO generated by inducible nitric oxide synthase, an enzyme that produces NO, inhibits the SARS CoV replication cycle. Nitric oxide has a dual personality and may act as an antioxidant.
Antioxidants are believed to optimize immune function – potentially valuable in outbreaks such as COVID-19.
Stephen Bray 2020