Researched information you must know about COVID-19, SARS, and MERS
Written by: Akshaya, Kavya, Haritha
Months have passed since the initial outbreak of COVID-19 yet there are still uncertainties that remain around the nature of the virus, its virulence, and possible treatments. Here we provide you with background information on COVID-19 and its similarities to MERS and SARS as well as a discussion of the latest research to engage our readers in understanding COVID-19 and its potential effects on shaping a new dynamic of our world.
“According to the Johns Hopkins website, on June 18, 8,367,894 cases were confirmed worldwide, with 2,163,290 in the United States alone. Additionally, in the United States, there have been 117,717 deaths (1).”
Coronavirus is not a novel virus. A strain of coronavirus (H1N1) caused the Spanish Flu in 1918, resulting in a global pandemic. SARS, identified in November 2002 and MERS, identified in 2012 were two other instances when this virus was expressed and caused several thousand deaths. Almost a century after the Spanish Flu, we are dealing with COVID-19. Different centuries, same virus. So you may be wondering, why are coronaviruses much more likely to cause global pandemics? Let’s start with a brief introduction to coronaviruses.
Coronaviruses have been in the human population for a long time; therefore, endemic in nature. Endemic means that the particular disease circulates in the population at any given time. There are four strains of coronavirus that are known to cause common colds and circulate during the flu seasons (1). These four strains were introduced to the human population before virology was established. As a result we do not have much evidence of how severe the infections were and how fast they spread during the initial introduction to the human population. In recent decades, two novel coronavirus strains were introduced into the human population, SARS, and MERS (1). These viruses, similar to other coronaviruses, are animal viruses that came into contact with the human population. Next, we give you an overview of the SARS and MERS outbreaks.
The SARS outbreak was first identified in Southern China in November 2002, with 792 cases and 31 deaths recorded by the month of March (4). SARS, or Severe Acute Respiratory Syndrome, resulted in gastrointestinal symptoms and often, a runny nose in those who contracted the virus (4). The spread of this coronavirus was due to the Asian civet cat, or the Paguma larvata, through open markets (pictured below, 8). The outbreak resulted in less than 8,000 cases and 774 deaths, with a 7% case-fatality rate. From 2004 onwards, there have not been any reported cases of SARS since the initial outbreak (4).
MERS, Middle East Respiratory Syndrome, was originally identified in the Middle East, specifically in Saudi Arabia, and was the second coronavirus to cause a global health crisis in modern history (4). The virus spread to 27 other countries, including Europe, Asia, and North America, and was transmitted through contact with transplanted individuals who had contracted the virus from the Middle East (4). Initially, the virus was identified in 2012 in an individual who had severe pneumonia but was labeled in 2014 as an outbreak with 662 cases and a case-fatality rate of 32.97%. There were a total of 2,494 laboratory-confirmed cases since 2012 and 858 deaths, resulting in a case-fatality rate of 34.4% (4).
SARS and MERS are associated with COVID-19 as they are beta coronaviruses causing respiratory syndromes along with other flu-like symptoms (we will discuss more in-depth about viruses in general in an upcoming blog post). You may be wondering, what does knowing about SARS and MERS achieve? Knowing the history of the virus helps in determining potential treatments that have been proven to be effective in controlling the previous outbreaks. The treatment methods and diagnosis for both SARS and MERS are similar. According to a research paper from the International Journal of Epidemiology, all three viruses are diagnosed using cell cultures of respiratory fluids (4). Although none have been approved for COVID-19, antiviral therapies were used to eradicate SARS and MERS and are being tested to potentially stop the spread of COVID-19 (4). Potential treatment options for COVID-19 are being reviewed, along with clinical trials examining the efficiency of antiviral therapies in the reduction or management of SARS and MERS (4). Common symptoms as a result of contracting SARS or MERS include a runny nose and gastrointestinal symptoms, but interestingly, these are rare in those who have COVID-19 (4). Comparing the impact of the three viruses, we can see that COVID-19 has had the biggest effects on a global scale. Now, let’s dive into COVID-19.
COVID-19 originated in Wuhan, China in December 2019. This virus is thought to be zoonotic, which means that the virus originated from animals, with a strong connection to bats (2). Researchers in China have been able to isolate a SARS-CoV strain that is 96% similar to the COVID-19 strain from horseshoe bats, reinforcing the zoonotic origin of the virus (2). COVID-19 spread to several other countries and the first confirmed case in the United States appeared in January 2020 (7). If SARS, MERS, and COVID-19 are all coronaviruses, why is COVID-19 also known as SARS-CoV-2 and not MERS-CoV-2? This is because COVID-19 has more than 70% genomic similarity to the SARS virus (3). In other words, the COVID-19 virus is more genetically similar to the SARS coronavirus than the MERS virus. Here are some recent statistics about the pandemic: According to the Johns Hopkins website, on June 18, 8,367,894 cases were confirmed worldwide, with 2,163,290 in the United States alone. Additionally, in the United States, there have been 117,717 deaths (7).
COVID-19 has been found to have many similarities with the flu. For example, in terms of symptoms, both viruses cause body aches, fever, cough, and fatigue (7). Sometimes, diarrhea and vomiting can also occur (7). In terms of transmission, both are spread by close contact with people, i.e, by talking, sneezing, or coughing. Both also tend to spread before symptoms are detected, making it harder to detect and control. (Note: There is a difference between the terms pre-symptomatic and asymptomatic. Pre-symptomatic people have not developed symptoms yet and could still spread the disease, whereas asymptomatic people do not develop symptoms at all; both can spread the disease). Neither virus is treatable with antibiotics, which only work on bacterial infections. However, the mortality rate of COVID-19 is significantly higher than ordinary flu (7). Both are treated by reducing symptoms such as fever. The best ways to prevent both the flu and COVID-19 are by frequent hand washing, staying home when sick, and avoiding contact with people, especially those who have underlying health conditions or are immunosuppressed (7). We are sure you have heard about the importance of wearing masks, nevertheless, we want to emphasize the importance here as well. As a contributing member of society and its welfare, it is highly recommended you wear a mask when you are in public and maintain six feet in distance. Masks help to mitigate the spread of the virus and save lives. Please do your part in combating the virus.
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