“Viruses face four basic challenges: how to get from one host to another, how to penetrate a cell within that host, how to commandeer the cell’s equipment and resources for producing multiple copies of itself, and how to get back out – out of the cell, out of the host, on to the next. A.”

“Viruses face four basic challenges: how to get from one host to another, how to penetrate a cell within that host, how to commandeer the cell’s equipment and resources for producing multiple copies of itself, and how to get back out – out of the cell, out of the host, on to the next. A.”

— David Quammen