SARS - The First Coronavirus Near-Pandemic

Genomics Revolution

Genomics Revolution

Guest Hosts: Denise Hart & Madyson Morris

Episode 53: SARS Coronavirus

Welcome to Genomics Revolution. This is Denise Hart and Madyson Morris from the 2020 Hiram College Genetics course hosting this episode on the SARS coronavirus. The acronym SARS stands for Severe Acute Respiratory System.1 To distinguish between the virus and the disease it causes, we will call the virus the SARS coronavirus and the disease SARS from here on out. Today, we will discuss the SARS coronavirus genome, as well as the outbreak that occurred across the globe from 2002 to 2003.

Did you know that SARS coronavirus was once the largest RNA virus genome? This genome is also single-stranded and it has 29,751 RNA molecules. The genome has 14 genes and 29 mature proteins. The largest gene found within the SARS coronavirus genome encodes a polyprotein. This polyprotein gets cut into 16 mature proteins. In addition to these mature proteins, the genome also shows that hypothetical proteins, unique to SARS-coronavirus, exist. Researchers used BLAST, along with other function prediction programs, to determine the function of these proteins.3Their research concluded that the genome has carbon-oxygen lyase, oxidoreductases that act on CH-OH groups, an ATP-binding cassette transporter, structural proteins, and a voltage-gated ion channel.3

So, why should we care about SARS coronavirus and the disease it causes? The outbreak started almost 20 years ago!2 We should care about understanding this virus because it causes most patients to develop pneumonia, hence the “Severe Acute Respiratory System” title. Pneumonia can be a very deadly disease if not treated right away. We should also care about educating ourselves on SARS coronavirus because during the outbreak, 8,098 people suffered from SARS as well as pneumonia or respiratory distress syndrome. 774 of those people died.1,2 If contracted, SARS coronavirus can have detrimental side effects, and having a good understanding of this virus could potentially prevent future outbreaks and pandemics caused by it.

SARS coronavirus originally started out in bat species, but is able to be contracted by humans. The symptoms of SARS coronavirus in humans include fever, dry cough, headache, muscle aches, and difficulty breathing. These symptoms are very typical of Coronavirus- and true for most of the 36 types of coronaviruses.6 While it is good to be aware of these symptoms, 1 symptom really sets SARS coronavirus apart from other strains: urinary abnormalities. For the first patients with SARS, they were diagnosed with other ailments due to these unique symptoms. It wasn’t until the genome was sequenced that researchers learned that SARS not only turns cells along the respiratory tract into host cells, but also cells in the intestines, liver, heart, vascular endothelium, testis, and the kidneys!6

Not only did some of the patients with SARS get treated for other ailments due to having urinary abnormalities, some of the patients with SARS received treatment but nothing happened!6,8 These were patients with the common symptoms. They received treatment but they did not get better. This was because the SARS coronavirus had mutated 14 times.6,7 Some patients had the original strain and others had one of the mutated strains. The treatment of the original strain did not help patients with a mutant strain. Researchers used high density sequencing arrays to find the places in the SARS coronavirus genome that had mutated.5,6 The scientists found that in mutant strains, 5-6 nucleotides were inserted or deleted. 5,6 This small change caused the virus to be harder to treat because of the variations between each mutation.

As these mutations were being discovered, the need to understand this virus was vital because of the global outbreak. Although there were not enough cases to consider it a pandemic, a virus causing a global outbreak still needs to be understood to prevent the outbreak from turning into a pandemic! In order for a disease to be considered a pandemic, it must affect several countries and a very large amount of people. The CDC does not define how many countries or people, but a pandemic does affect more people than an outbreak.4

It’s about time to wrap up. Today we learned about the SARS coronavirus and the global outbreak of SARS from 2002 to 2003. What we want you to take away from this episode of Genomics Revolution are four things:

Number 1: SARS coronavirus was one of the largest RNA virus genomes at the time. The size of the genome increased the amount of time needed for geneticists to understand the virus to create presentation education and control measures for the public.

Number 2: Whenever the SARS coronavirus genome experiences a mutation, the mutation is an insertion or deletion of 5 or 6 nucleotides.

Number 3: While SARS is an acronym for Severe Acute Respiratory System, the virus targets not just the respiratory tract, but also other organs such as the kidney and heart.

Number 4: Understanding viruses like this one is important to the future of science so that when a new strain of virus arises, we may be able to fight it quicker than the last one!

Thanks for listening to Genomics Revolution. Bye guys! Bye!

References:

1. SARS. Centers for Disease Control and Prevention. 2017 Dec 6 [accessed 2020 Apr 9]. https://www.cdc.gov/sars/about/fs-sars.html

2. SARS (Severe Acute Respiratory Syndrome). World Health Organization. 2012 Apr 26 [accessed 2020 Apr 9]. https://www.who.int/ith/diseases/sars/en/

3. Cai CZ, Han LY, Chen X, Cao ZW, Chen YZ. Prediction of Functional Class of the SARS Coronavirus Proteins by a Statistical Learning Method. Journal of Proteome. 2005 Aug 10 [accessed 2020 Mar 28]. https://doi.org/10.1021/pr050110a

4. Caceres V. What's the Difference Between an Epidemic and Pandemic? U.S. News & World Report. [accessed 2020 Apr 9]. https://health.usnews.com/conditions/articles/whats-the-difference-between-an-epidemic-and-pandemic

5. Wong CW. Tracking the Evolution of the SARS Coronavirus Using High-Throughput, High-Density Resequencing Arrays. Genome Research. 2004;14(3):398–405. doi:10.1101/gr.2141004

6. Cheng VC, Lau SK, Woo PC, Yuen KY. Severe Acute Respiratory Syndrome Coronavirus as an Agent of Emerging and Reemerging Infection. American society for microbiology. 2007;20(4):660–694.

7. Graham RL, Sparks Jifr S, Eckerie LD, Sims AC, Denison MR. SARS Coronavirus replicas proteins in pathogenesis. Virus Res. 2008;133(1):88–100.

8. Hung LS. The SARS epidemic in Hong Kong: what lessons have we learned? Jrsm. 2003;96(8):374–378. doi:10.1258/jrsm.96.8.374