Introduction to Covid 19 Coronavirus | History | SARS

This Article is on an introduction to Coronaviruses including SARS, MERS and the new corona virus from Wuhan China.

In the summer talk about what Coronaviruses are we’re also going to talk about what animals are infected with Crona viruses and animals that act as hosts for corona viruses.

We’ll also discuss some of the common signs and symptoms of Cronavirus.

Article we discuss about a brief history of epidemics caused by corona viruses including SARS, MERS and the new corona virus.

Introduction of Coronavirus

So corona viruses are a family of RNA viruses in the order known as Nidovirales.

Corona viruses are significant viral pathogens in both humans and animals they can cause significant disease and the word corona virus.

The prefix corona actually comes from the Latin word for crown and it’s actually due to or named for the crown like appearance of the virus.

Here is a electron microscope image of a corona virus and as you can see here these are the membrane surface proteins and it looks a bit like a crown.

There are four classifications of corona viruses

  • Alpha
  • Beta
  • Gamma
  • Delta

so it’s very easy to remember.

Human coronaviruses are alpha and beta corona viruses so the corona viruses we discuss talk about and we hear about are in the first two classifications alpha and beta.

Corona viruses are medium-sized viruses that envelope a positive stranded RNA in the corona viruses themselves a very large viral RNA genome they have the largest viral RNA genome known.

Hosts, Reservoirs and Infected Animals

What are some of the hosts and reservoirs of these viruses and what animals are infected by these viruses?

1. So corona viruses infect both birds and mammals but bats are hosts to the largest number of viral genotypes of coronavirus.

2. They act more as hosts they don’t necessarily become infected with these viruses they become hosts to many number of viral genotypes of Cronavirus. So their immune system is able to suppress a lot of these viruses and they simply act as hosts but they can transmit these viruses to other birds and mammals

3. Epidemics from Cronaviruses generally occur when viruses are transmitted from one species to another

The viruses can acquire or develop mutations in proteins on their envelope to allow them to bind to cells and infect other cells more easily

so this is why we see that when viruses can be transmitted from one species to another they can acquire mutations and acquire new abilities to infect cells of other species

so this is why it’s important or it’s significant when coronavirus gets transmitted from one species to another.


1. With regards to humans human coronaviruses are causes of both respiratory and gastrointestinal tract infections.

2. These human coronaviruses are relatively common causes of illness in humans and it’s estimated that coronaviruses account for approximately five to ten percent of all adult upper respiratory tract infections. They can cause a lot of respiratory tract infections anywhere from a common cold to pneumonia and acute respiratory distress syndrome are ARDS.

so there’s a wide variety of signs and symptoms from corona viruses

so there are several corona viruses that humans are infected with more often and then there’s other ones that cause more significant illnesses and infections

and some corona viruses can even cause GI or gastrointestinal tract infections

and common symptoms of gastrointestinal tract infections with corona viruses includes diarrhea

3. When mutations occur corona viruses can be significant causes of human epidemics.

As we mentioned before a lot of times these mutations can occur when the virus is transmitted from one species to another or an entirely new corona virus can be developed through these mutations.

We have seen several instances in the recent past where there has been transmission from one species to another leading to a new virus and a new outbreak of corona virus.

History of Coronavirus

The first one is SARS severe acute respiratory syndrome or serves and this occurred in the years 2002 to 2003.

Early reports show it in early 2003 but it was likely occurring even before that in 2002

It seems have started in Guangdong Province of China and it is itself a beta corona virus and it is said to be in the lineage be beta coronavirus.

There are different lineages within the beta Crona virus category and SARS is in lineage B.

What seems have occurred is that this particular corona virus SARS was transmitted from bats to civets to humans.

so from bats to civets and all the way to humans.

This led to a worldwide outbreak and the outbreak was recorded as early as February 2003 and it seemed to have lasted until July of 2003 and there were more than 8,000 recorded total cases and 774 deaths with a fatality rate of 9.6 percent.

Another chrono virus outbreak was the Middle East respiratory syndrome or MERS outbreak which occurred in 2012.

This started in Saudi Arabia and it quickly spread to several countries it itself is a beta corona virus as well.

What seems to have occurred here is that the virus was transmitted from camels to humans so either through eating camels or exposure to camels or drinking camel milk.

There are more than 2,400 cases of MERS with a recorded 858 associated deaths with a fatality rate of approximately thirty four point four percent so very high fatality rate with the MERS infection.

The newest one that has come on the scene is the 2019 novel coronavirus and it’s designated 2019 – n CoV.

This one occurred in December of 2019 it’s probably even earlier than that we’ll talk about more about that in the next lesson and this fire started in Wuhan a city in Hubei Province of China.

Also Read: How Does Coronavirus Affect Your Lungs

It is the seventh Cronavirus found to cause illness in humans

Like SARS and MERS it is itself a beta Crona virus and it has a lot of similarities to SARS which we’ll talk about in the next lesson as well.

What seems to have taken place here is that right now we’re not sure exactly how it was transmitted there was some early evidence suggesting that it was transmitted from snakes to humans but now some evidence is suggesting it’s more likely that came from bats

There was an animal market in Wuhan that seemed to be the epicenter for this outbreak and it has suggested that there were six post to live and dead animals.

Right now it is suggested it was bats that was the source of this virus.

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