Sunday, April 19, 2020

Disease Post: COVID-19/SARS-2

As we are in the midst of a pandemic, I thought I would do a little post about this disease. I am not an expert on this topic, but I want to try to convey some information to people who are interested.


Coronaviruses are enveloped viruses. Their genome is RNA, which makes them more prone to mutations, much like the influenza virus. The surface of the envelope is covered with club-shaped spikes or projections which give it a "corona" or crown when looked at under a microscope.

Giant COVID-19 virus from Giant Microbes. Super cute. I want all of their plushy diseases!
Coronaviruses are broken down into four groups: alpha, beta, gamma, and delta. Mostly this helps differentiate the animals the virus originated in: rodents and bats for alpha and beta, birds for gamma and delta. Based on this you can probably gather that coronaviruses are present in several animal species. And you would be correct. Animals all over the world have coronaviruses which usually cause respiratory and/or gastrointestinal diseases. Humans have coronaviruses, too. Some do cause gastrointestinal infections, but many cause upper respiratory infections that are pretty mild. They are usually what we would call a chest cold or viral upper respiratory infection (ie: viral bronchitis). Most people don't have trouble clearing these infections.

But coronaviruses are good at mutating. That means that they have the potential to jump to humans from animal hosts, which is likely how we ended up with SARS, MERS, and SARS-2 (aka COVID-19, SARS-CoV-2, nCoV-19). For the record, SARS stands for "severe acute respiratory syndrome" and MERS stands for "Middle Eastern respiratory syndrome." And real quick before we move on because I have seen bad information spread on social media: COVID stands for "coronavirus disease" and CoV is short for "coronavirus." The number 19 refers to the year 2019 when the first case emerged. SARS could also have been called COVID-02 (2002) and MERS could be called COVID-12 (2012).

The severe coronavirus infections that we hear about cause atypical pneumonia (generally less severe than typical pneumonia). Most coronaviruses do not establish infections deep in the lungs for various reasons (including cell receptors that they need to enter cells and temperature of the upper versus the lower respiratory system). But SARS, SARS-2, and MERS were able to establish infections in the lower respiratory tract which makes them much more dangerous.

According to the WHO, "SARS was more deadly but much less infectious than COVID-19. There have been no outbreaks of SARS anywhere in the world since 2003." But SARS-2 is genetically related to SARS so we might be able to learn more about SARS-2 by studying SARS.

How is it spread?

Respiratory coronaviruses are spread by droplets in the air, gastrointestinal coronaviruses are spread via the fecal-oral route (I know, gross). SARS, SARS-2, and MERS are respiratory and caused by inhaling the virus.

Image from the CDC
These infectious droplets of saliva  or nasal discharges (fluid) are in the air because people cough and sneeze. Even laughing and singing release droplets. This is why the CDC is now recommending that everyone in public wear a mask of some sort (preferably one that is thick enough to stop droplets). It isn't to protect the wearer, it is to protect the people around you. Also, cover your coughs and sneezes. The droplets are heavy, however, and usually settle pretty quickly, which can contaminate surfaces.

It has been thought that the virus can live for a time on surfaces. Here is what the WHO has to say:
It is not certain how long the virus that causes COVID-19 survives on surfaces, but it seems to behave like other coronaviruses. Studies suggest that coronaviruses (including preliminary information on the COVID-19 virus) may persist on surfaces  for a few hours or up to several days. This may vary under different conditions (e.g. type of surface, temperature or humidity of the environment).
If you think a surface may be infected, clean it with simple disinfectant to kill the virus and protect yourself and others. Clean your hands with an alcohol-based hand rub or wash them with soap and water. Avoid touching your eyes, mouth, or nose.

For those worried about catching SARS-2 from animals, the WHO also says, "While there has been one instance of a dog being infected in Hong Kong, to date, there is no evidence that a dog, cat or any pet can transmit COVID-19. COVID-19 is mainly spread through droplets produced when an infected person coughs, sneezes, or speaks. To protect yourself, clean your hands frequently and thoroughly." So don't go dropping your pets off at shelters or (heaven forbid) outside somewhere to fend for themselves. Take care of your animals, they are not going to give you SARS-2. It might be possible for you to give your pet the disease, some animals have lungs much like humans--cats and ferrets for instance. There doesn't seem to be much official information about this and we might not know for a while. Just be cautious. Wash your hands.

Additionally, it appears that the virus does not transmit across the placenta according to an article by Fan et al. Obviously, pregnant and breast-feeding women who are exposed or experiencing symptoms should consult their doctor. More research on this topic is needed, but right now it seems hopeful.

Image from Harvard Coronavirus Resource Center


Keep in mind with SARS-2 that some people experience very mild symptoms while others do not. That's part of why this is so dangerous. What doesn't hurt you much could kill someone else. And there is some evidence that there are people who are asymptomatic carriers (they don't feel or appear sick even though they have the disease). However, since they are not showing symptoms (namely coughing) it is more difficult for them to actually spread the disease. Also more difficult to know who is infected. It is a good idea to act as though anyone and everyone might be infected, including yourself.

Within about 7-14 days of infection, people generally show fever, dry cough, tiredness, aches, sore throat and/or shortness of breath. Very few people have reported diarrhea, nausea, and runny nose.

If symptoms get more severe, you should seek medical attention. According to the CDC, if you experience the following: "trouble breathing, persistent pain or pressure in the chest, new confusion or inability to arouse, bluish lips or face" then you should seek emergency medical attention.

I know this is all scary and its still so new that we don't have all of the details, but this is part of why it is important to take care of yourself and keep yourself (and others) healthy. And do keep in mind that many people have more mild infections and recover fine on their own. An article written by

Prevention and Treatment:

The WHO recommends the following for prevention:
  • Wash your hands regularly with soap and water, or clean them with alcohol-based hand rub.
  • Maintain at least 1 metre distance between you and people coughing or sneezing.
  • Avoid touching your face.
  • Cover your mouth and nose when coughing or sneezing.
  • Stay home if you feel unwell.
  • Refrain from smoking and other activities that weaken the lungs.
  • Practice physical distancing by avoiding unnecessary travel and staying away from large groups of people. 
As of right now, there is not a vaccine or a proven treatment. And I do not want to get political, but Americans: do NOT follow the directions of our president. He is not a medical doctor or a medical professional of any kind. Just because he thinks or "feels" that something might be so, does not mean it is. Please listen to doctors and legitimate medical professionals. It has not been solidly proven that hydroxychloroquine will treat the disease and may cause more harm than good in some cases. There have been lab trials using cell cultures (in vitro) that show decreased levels of disease by SARS-2, but there have been very few good clinical trials. Most have had too small a sampling group to give accurate representation (see Gautret et al.).

I'm not sure what sort of mechanism azithromycin is supposed to use to treat a viral infection. But azithromycin is an antibiotic, meaning it is meant to treat bacterial infections. It could help treat secondary infections people may see with SARS-2 infections, but to my knowledge, will not treat the virus. Please only use antibiotics at the direction of your doctor.

Also, please be aware that development of vaccines and treatments are a long process, usually at least a year if rushed. So scientists are trying to find these things, but please know that it will be a while before these things exist.

As of right now, treatment consists of supportive care.


Here is an informational video that has some good information and breakdowns of COVID-19 that might interest you: Ninja Nerd Science: COVID-19 | Coronavirus: Epidemiology, Pathophysiology, Diagnostics and Ninja Nerd Science: COVID-19 | Coronavirus: Treatment, Prognosis, Precautions.

I also highly recommend checking out This Podcast Will Kill You. About two months ago they did a general coronavirus episode and more recently they have done a series all about COVID-19. They are knowledgeable and work with other professionals to get good information out there.

Here is a page that is very important: WHO: Coronavirus disease (COVID-19) advice for the public: Myth busters. Take a look at the information and graphics. I would also like to add a rumor I heard a couple of times: that darker skinned people are less prone (they aren't and also tend to be at a lower socioeconomic status and therefore have less access to treatment and can be more prone to severe disease) and that wearing sunscreen will help protect you from COVID. The virus does not and will not absorb through your skin. Even if there is a break in the skin, I am not sure that coronavirus could properly establish an infection. Covering your skin or having darker skin will not prevent coronoavirus infection.

And I'm sure you know this, but many people have been negatively infected by this pandemic. People have lost friends and family, people have been laid off of work and struggle to make ends meet, our health care professionals and other necessary personnel are worked to the bone. Please keep these people in mind. If it is within your power and means to donate to organizations dedicated to helping these people, please do. Here are a couple of suggestions: your local food banks (like Food Bank of the Rockies), Give Directly, No Kid Hungry, local COVID relief funds, United Way, and many others.

There are local people everywhere doing things to try to help their communities, doing things like delivering food/supplies, giving gift cards to families, and so forth. Also, please keep in mind the homeless populations who also need extra help during these times. Most shelters take food and monetary donations and may need supplies or volunteers. There are people doing good deeds for our health care workers and essential personnel. Remember that many of these people are not being treated well or paid well despite the fact that we actually need them to keep going as a society.

If you can't donate or volunteer, there are still things that you can do: stay home, stay away from people as much as possible, don't travel, and be kind. Kindness doesn't cost anything and empathy is going to help people much more than anger and bitterness. This is difficult for everyone, but please do your part.

Disclaimer: This information is bound to change. We won't know all of the information including complete statistics of infection rates, death rates, and more until this is all over. Scientists and doctors are working all of the time to add to our knowledge of this disease. If any of this changed/changes, feel free to let me know.

Centers for Disease Control: Coronavirus disease 2019 (COVID-19)
World Health Organization: Coronavirus disease 2019
Cascella et al. Features, evaluation and treatment coronavirus.
Gautret et al. Hydroxycholoroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial.
Omer et al. The COVID-19 Pandemic in the US: A Clinical Update.
Bao et al. Reinfection could notoccur in SARS-CoV-2 infected rhesus macaques. (Please forgive this link, this is the article but the site it was posted on was having problems opening  by the time I was writing this post.) 
Fan et al. Perinatal Transmission of COVID-19 Associated SARS-CoV-2: Should We Worry? 
Emerging Infectious Diseases by Lisa A. Beltz
Medical Microbiology 6th edition by Patrick R. Murray, Ken S. Rosenthal, and Michael A Pfaller

No comments:

Post a Comment