Assertion: smallpox | /r/CreatedBy | either of two virus variants
Facets:
Source sentences:
text: Smallpox is caused by either of two virus variants named Variola major and Variola minor.
text: Smallpox was an infectious disease caused by one of two virus variants, Variola major and Variola minor.
text: Smallpox was an infectious disease unique to humans, caused by either of two virus variants, Variola major and Variola minor.
text: Smallpox is an infectious disease unique to humans, caused by either of two virus variants named Variola major and Variola minor.