translation.en: Smallpox was a systemic disease, officially eradicated since 1979, caused by infection with the Variola major virus, whose only reservoir was infected humans.
translation.sv: Smittkoppor var en allvarlig sjukdom som är officiellt utrotad sedan 1979. Sjukdomen orsakades av infektion med viruset Variola major, vars enda reservoar var smittade människor.