Here’s a look at smallpox, a contagious and sometimes fatal infectious disease. The most severe and most common form of the smallpox virus is known as variola major. Smallpox is transmitted through ...

Here’s a look at smallpox, a contagious and sometimes fatal infectious disease. The most severe and most common form of the smallpox virus is known as variola major. Smallpox is transmitted through ...

Here's some background information about smallpox, a contagious and sometimes fatal infectious disease. The most severe and most common form of smallpox is known as variola major, which has four ...