What is the difference between variola major and variola minor?
What is the difference between variola major and variola minor? Smallpox is caused by 1 of 2 closely related strains: variola major and variola minor. The 2 viruses are indistinguishable except by polymerase chain reaction (PCR) testing. Variola minor infection (known as Alastrim) causes fewer systemic symptoms, a less extensive rash, less scarring, and fewer […]