Variola major and West Indian smallpox

Variola major noun - A highly contagious viral disease characterized by fever and weakness and skin eruption with pustules that form scabs that slough off leaving scars.

West Indian smallpox and variola major are semantically related. In some cases you can replace phrase "West Indian smallpox" with "Variola major", this phrases are similar.

West Indian smallpox noun - A mild form of smallpox caused by a less virulent form of the virus.

Variola major and West Indian smallpox are semantically related. You can use "Variola major" instead a noun phrase "West Indian smallpox".