Any of a group of viruses which cause cowpox, smallpox and related diseases.
One of a group of large DNA containing viruses including those, that cause smallpox (variola) and cowpox (vaccinia) in man, and pox and tumors in animals.
One of a group of DNA viruses that produce characteristic spreading vesicular lesions, often called pocks. It is the largest of the true viruses and includes viruses responsible for smallpox, vaccinia, molluscum contagiosum, and orf.