COVID 19 Evolution
Updated: Apr 26, 2020
The Corona Virus- Covid 19, although a Novel virus, its history goes back to 2012. In this instance, the virus evolved to its current pathogenic state (in a non-human host) and then jumped to humans. Also known as a Zoonotic Disease .
This is how the previous Corona Virus outbreaks like SARS have emerged with humans contracting the virus after direct exposure to Civets, after the virus originated in bats. The exposure caused Severe Acute Respiratory Disease (SARS).
In 2012, the virus transmitted from bats to camels causing Middle Eastern Respiratory Disease (MERS) in humans. With the SARS the spread of the virus R0 was low (R-naught represents the number of new infections estimated to stem from a single case). Also, the fatality rate with SARS was high although the R0 was low, considering total cases infected were 8500 with 800 fatalities, 10%.
This research proposed bats as the most likely reservoir for SARS-CoV-2 as it is very similar to a bat Corona Virus. There are no documented cases of direct bat-human transmission, however, suggesting that an intermediate host was likely involved between bats and humans.
In the MERS R0 also was low infecting close to 2,500 but killing 800, 32% fatality rate.
In Covid 19 scenario, both of the distinctive features of SARS-CoV-2's spike protein the RBD portion that binds to cells and the cleavage site that opens the virus up would have evolved to their current state prior to entering humans. In this case, the current epidemic would probably have emerged rapidly as soon as humans were infected, as the virus would have already evolved the features that make it pathogenic and able to spread between people.
In this instance, a non-pathogenic version of the virus jumped from an animal host into humans and then evolved to its current pathogenic state within the human population.
For instance, some Corona viruses from Pangolins, Armadillo-like mammals found in Asia and Africa, have an RBD structure (glycoproteins binding sites) very similar to that of SARS-CoV-2. A coronavirus from a Pangolin could possibly have been transmitted to a human, either directly or through an intermediary host such as civets or ferrets.
The danger of this virus compared to the flu virus is the R0 for the corona virus is 3 compared to the influenza being 1. You can imagine how the curve will spike sharper and faster with the corona infection compared with the influenza being almost flat from the start.
-Top Hakx! Research Before You React!
Try not to rely only on general media sources that may have an agenda and aim at “headline” “click bait” material, often not fact checked or with relevant information left out. You can research through places like PUBMED where actual medical specialists have published research that may not be conclusive but generally science based, and updated as discoveries are made.
Links for other relevant sites below:
Dr. Frank J Akawi, BS, MS, MBA, PhD, DVM, CVA, CCRT
Greenfield Animal Hospital