A single critical factor was a scientific understanding with regards to the virus alone. Virologists had come to feel that variola could endure and replicate only within human beings. Lots of viruses that bring about sickness in human beings could also infect animals — imagine Jenner’s cowpox. But variola experienced https://sjjfawt.frewwebs.com/26671786/manual-article-review-is-required-for-this-article