What is COVID-19?

by Susan Walker May 10, 2020

COVID-19 has stopped the world in its tracks. There is no doubt about that. It has shuttered businesses, wiped out finances, suspended the economy and regrettably, taken lives. It has wreaked havoc on the world at large and we are still unsure what to do about it. So what are we talking about here? What exactly IS COVID-19?

COVID-19 is part of a family of viruses called coronaviruses, named because of their spiked surface proteins which give them a crown appearance. They are part of the family Coronaviradae. Coronaviruses are enveloped (like influenza). This means they are covered by a membrane of cellular matter taken from their host cell. The coronavirus is an RNA virus. 

There are seven known coronaviruses that infect humans. Four of them cause the common cold and affect the UPPER respiratory tract (nose and throat). As a result, they cause symptoms such as a sore throat and runny nose. 

The three coronaviruses that cause major human disease are:

  1. SARS-CoV
  2. MERS-CoV
  3. SARS-CoV-2 (the novel coronavirus)

What do these mean? SARS stands for Severe Acute Respiratory Syndrome. MERS stands for Middle Eastern Respiratory Syndrome.  So all of these viruses mainly affect the lower respiratory tract which includes lung tissue.

The Novel Coronavirus

The novel coronavirus is officially called SARS-CoV-2 and it results in the disease called COVID-19.

How it's spread:

  • Large respiratory droplets
  • Fecal-oral route (possible) 
  • Surfaces infected by respiratory droplets
  • Aerosols

The incubation period is 1-14 days. 


Symptoms include fever, cough and difficulty breathing. More severe cases have lymphopenia (low levels of lymphocytes in the blood) and chest imaging that looks like pneumonia. Patients can develop acute respiratory distress syndrome (ARDS), septic shock, metabolic acidosis, coagulation dysfunction and death. 

SARS-CoV-2 can cause damage to the airway epithelial cells. Patients are not able to clear their lungs of dirt or mucus and this can cause pneumonia. They also show symptoms of a cytokine storm which is an increase in the levels of cytokines which cause inflammation. 

The symptoms of viral diseases result from the immune response to the virus. This happens because the body tries to control and eliminate the virus.

While most of what we are doing is trying to curb the spread of the virus, an importing aspect of actually fighting it is through supporting our immune function. You can find out how in our next post.

Susan Walker
Susan Walker

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