Pigs catch coronavirus but don't get sick, scientists may know why

Recommendable! Why are pigs coping with the coronavirus much better than humans? Apoptosis versus necrosis!

"SARS-CoV-2, the novel coronavirus that causes COVID-19, is itself thought to be a zoonotic disease, meaning it originates from animals ... how it made that jump to humans remains a matter of debate. 

As a zoonotic disease, it is unsurprising that many different types of animals have also been able to contract the virus. In particular, cats, dogs, ferrets, minks, deer, tigers and hamsters have all been able to contract the virus, become sick and, in some cases, spread it. Further, these were also known to be reverse-zoonotic transmissions, also known as zoo-anthroponotic transmission, meaning they were infected by humans.
From the start of the pandemic, it was known to scientists that pigs could also be infected with coronavirus, though they would need to be exposed to large amounts. ...

To find out, the scientists introduced samples of the virus to cell cultures derived from respiratory epithelial cells ...

While the human cell culture acted as expected, the pig cell culture did something different. Essentially, in response to being infected by SARS-CoV-2, pig cells just died, the nuclei of their cells shredding into fragments. 

This type of controlled cell death is called apoptosis, and while the term cell death might sound scary, it actually means that rather than spreading the infection to the other cells ...

This is not a phenomenon exclusive to pigs; humans are known to do this too, including in response to the coronavirus. But pig cells are 100 times more likely to do so.

Rather than apoptosis, human cells are far more likely to undergo a process known as necrosis. This is another form of cell death, but unlike apoptosis, it is far less controlled. When a cell undergoes necrosis, it releases its contents into its surroundings. This results in everything spreading and triggering a very strong hyperimmune response. ..."

From the abstract:

"... Further analysis confirmed an early and enhanced apoptotic mechanism driven through caspase 3/7 activation, limiting SARS-CoV-2 propagation in PRECs [porcine respiratory epithelial cells] compared to HRECs [human respiratory epithelial cells. Our findings shed light on a possible mechanism of resistance of pigs to SARS-CoV-2 infection, and it may hold therapeutic value for the treatment of COVID-19."

Pigs catch coronavirus but don't get sick, scientists may know why - The Jerusalem Post When infected with the novel coronavirus, pig cells undergo a sort of strategic suicide called apoptosis, which kills the infected cells and stops them from spreading the virus.

Enhanced apoptosis as a possible mechanism to self-limit SARS-CoV-2 replication in porcine primary respiratory epithelial cells in contrast to human cells (open access)