Which disease is caused by Variola virus?

Which disease is caused by Variola virus? The answer is smallpox.

Smallpox was a severe contagious disease caused by variola viruses, mainly Variola major and Variola minor. It typically produced fever followed by a characteristic progressive rash whose pustules developed at roughly the same stage across the body. Severe cases could cause blindness, scarring, or death.

Vaccination made smallpox the first human disease eradicated worldwide. Edward Jenner’s 1796 work showed that exposure to cowpox could protect against smallpox, providing the foundation for vaccination. Later, coordinated international campaigns used vaccinia-based vaccines and intensive case detection.

The World Health Organization certified global eradication in 1980 after the last naturally occurring case was recorded in Somalia in 1977. Smallpox is not the same as chickenpox: chickenpox is caused by varicella-zoster virus, while smallpox was caused by variola virus. The two illnesses also differ in rash pattern and severity.