In the last few months, the outbreak of COVID-19 has brought the coronavirus back into the public eye after it had remained relatively silent since 2003 .
Yet the coronavirus genome remains a mystery, especially to those outside the scientific community. Let’s shed some light on this global pandemic by viewing coronavirus under an electron microscope..
What Is a Coronavirus Genome?
The name Coronavirus is derived from the Latin word “corona,” meaning crown or halo, in reference to the spike peplomers surrounding the particles. This halo is commonly seen when viewing the virus with an electron microscope.
Coronaviruses are known to affect animals, bats being a prime carrier of the virus, with other strains carried by camels or civet cats. Transmission to humans from animals is fairly rare, but once the virus has made its way into the human body, rates of transmission from person to person increase dramatically.
There are several different kinds of coronaviruses, only one of which causes the COVID-19 that’s disrupted life all over the globe. Other well-known coronaviruses are causes for Middle Eastern respiratory syndrome and SARS, the infamous virus from the early 2000s..
Coronavirus Under an Electron Microscope: 4 Common Strains
Of the seven types of coronaviruses, four of them are pretty much harmless. The strains 229E and NL63 are classified as alphacoronaviruses , while OC43 and HKU1 are betacoronaviruses . These four types are seen among humans quite frequently, and they are causes of the common cold.
However, there are three more severe strains of the virus. Here’s a glimpse at what they look like under the microscope:
Human coronavirus 229E, magnified to x60,000 via negative contrast electron microscopy
(Micrograph from F. A. Murphy, University of Texas Medical Branch, Galveston, Texas.)
This is a more severe strain of coronavirus, and it’s far more deadly than the common cold. MERS-CoV, which stands for Middle Eastern respiratory syndrome, was first reported in Saudi Arabia in 2012. Since then, about 37% of those infected have died.
(Image from Cynthia Goldsmith/Azaibi Tamin) Electron micrograph of MERS-CoV
This coronavirus rose to infamy back in 2002-2003, when it swept across 26 countries, infecting some 8,000 people with influenza-like symptoms. SARS-CoV , severe acute respiratory syndrome, was the precursor to COVID-19, and it fizzled out after about 9 months .
(Image from C.D. Humphrey, CDC) SARS-CoV particle via a negative stain electron microscope.
This strand is the cause for the current public outbreak of COVID-19. SARS-CoV-2 is very similar to MERS-CoV and the original SARS-CoV, and it was first discovered in China at the end of 2019. At the time of this article, there have been about 140,000 cases of COVID-19, with a current mortality rate of 7%.
In mid-February, NPR published an article that displayed images of SAR-CoV-2, taken from under the keen eye of a scanning electron microscope.
(Image from NIAID-Rocky Mountain Laboratories) SARS-CoV-2 viewed using a scanning electron microscope.
Coronavirus Vs. Flu
If you simply compare these two viruses, it might seem like they’re identical. The symptoms for both COVID-19 and the flu include:
Aches and fatigue
Vomiting and/or diarrhea.
However, COVID-19 is still new and relatively unstudied. Whereas the flu has been researched and a vaccine has been developed, COVID-19 does not have a vaccine .
The main difference between the two is that COVID-19 is transmitted via the air, making it far more contagious than the flu. This fact has induced much of the media and civilian panic, even though the number of deaths from COVID-19 is significantly smaller than that of the flu .
Mainly, complications arise for people that already have a compromised immune system, and death is related to pneumonia and other illnesses that develop from catching coronavirus.
COVID-19 in the Future
The World Health Organization has stated that, unlike the seasonal flu, COVID-19 is containable. Numerous countries have taken steps to minimize rates of transmission by canceling public events, closing off high-traffic areas, and issuing health safety information.
Scientists are hard at work to categorize the coronavirus genome, which helps to understand its transmission path and any mutations it developed along the way.
As microscope experts, we'll definitely be watching this crisis closely. For more fascinating and educational articles about microscopes, visit our Education Center.