A detailed look at COVID-19

A Detailed Look at COVID-19


As COVID-19 continues to spread throughout our community and indeed throughout the world, we wanted to tell you a little bit more about the virus and its origins. COVID-19 is the illness caused by the 2019 novel coronavirus known as SARS-CoV2.

About the Virus

The virus was first reported in the city of in Wuhan, in the province of Hubei in China in late December 2019. It is thought to have originated in chrysanthemum bats. It is likely that it was transferred between bats and humans via the pangolin, a scaly anteater. This mammal is an endangered species and is commonly trafficked.

The virus itself, SARS CoV-2, is covered in spikes which gives the appearance of a crown, hence the name coronavirus. The name is derived from the Latin for Crown – Corinum. The spikes can bind tightly to the angiotensin-converting enzyme 2 (ACE2) receptor in humans.  These ACE2 receptors appear in large numbers in the respiratory tract.

The ACE2 enzyme is present in Type II alveolar cells where it has a role in regulating their survival. These Type II alveolar cells make up only 15% of the cells in the lung but they have an important role. These cells make a substance called surfactant. Pulmonary surfactant helps reduce the surface tension of the alveoli, the small sacs in the lungs allow oxygen to reach the bloodstream. Reducing the surface tension of the lungs makes them softer and allows them to inflate more easily. The virus gets into these cells where it replicates rapidly eventually destroying the cell.

I often like to think of the lining of the lungs, known as the epithelium, as being like a strip of bars and clubs. Think of the Type II alveolar cells as being like the clubs. Only a small proportion of all the establishments along the strip are clubs but nevertheless they are important. Think of a virus as being like a rowdy stag do and hen do. The ticket they have to get in the club is the spikes on their crown. Inside the club, they replicate and eventually trash the place. They then go on to the next club and do the same thing. Eventually the strip gets completely overwhelmed.

How long does it take to get symptoms if you’re infected?

It is thought that after becoming infected it takes anywhere between 1 and 14 days to develop symptoms and an average of about 5 to 6 days. The virus is mostly spread by droplets and aerosol (small droplets). It seems a significant mode of transmission of the virus is from patients to healthcare workers to other patients and healthcare workers. For this reason, I think it’s really important that Healthcare workers social distance from each other while at work to the greatest extent possible and wear the best masks available.

Importantly, the virus can persist on surfaces that have been coughed or sneezed on. An important way to block transmission is therefore regularly cleaning surfaces and frequently washing hands.

 What are the symptoms of COVID-19? 

The most common symptoms of COVID-19 have been reported as being fever which is typically not very high ( around 38℃) and cough. Muscle aches, chest pain and headache have been less commonly reported. However, amongst our group of patients and these have been very common symptoms. Many of our patients have had a headache behind the eyes. in addition, people have also been reporting an altered taste and smell. Several of our patients have reported a metallic taste in their mouth with the sensation of having licked a battery. Shortness of breath is thankfully a relatively rare symptom. However, it does represent more serious illness.

How to reduce your risk?

The most important steps in trying to reduce the transmission of this virus is limiting contact with people.  humans are social animals and social distancing is very difficult. However, if we are to stop the spread of this virus it’s something we must do. If you do have to go out when you come back in wash your hands and wash your hands more frequently during the day.

If you are concerned that he might have coronavirus then call your doctor or NHS 111.

Dr Hugh Coyne