Since the outbreak, different coronaviruses have been discovered in different bats and in pangolins species.
A study shows that the genetic sequence of a virus identified in one bat species is 96% similar to that of the novel coronavirus which indicates that bats could be the reservoir of COVID-19 coronavirus.
Researchers also found a similar virus to the current coronavirus in pangolins. The virus in pangolins has a 99% of genomic similarity in the region that allows the virus to enter human cells to infect them. In the bat species, this region has only 77% similarity.
These studies suggest that 2 viruses, one in bat and another in pangolin may have recombined which results in new SARS-CoV-2. For this recombination to occur, both the viruses should have infected the same organism at the same time. It is still unclear in which organism this recombination occurred.
Even though the SARS-CoV-2 originated in animals. It is very effective in causing diseases in humans. Several features of SARS-CoV-2 makes it very successful in causing the epidemic.
Coronaviruses are surrounded by a halo of spikey proteins. These spikey proteins stick out like tips on a crown and help the virus attach itself and gain entry into the host cell. The spikes recognize and stick to a receptor protein called ACE2, which is found on the surface of human cells.
The spikes of SARS-CoV-2 allows it to stick to our cells far more effectively than other types of coronaviruses. Most respiratory viruses infect either the upper or lower airways. In the case of new coronavirus, both upper and lower airways are infected. Some viruses are highly contagious, while other viruses are less.
The novel coronavirus spreads between people before any symptoms show up which makes it easy for the virus to transmit to multiple hosts and makes it difficult for us to identify and control it.