Is smallpox viral or bacterial?

Is it contracted because of bacterial or viral infections?

It's a virus, it can't be treated, it just runs it's course.

Smallpox is a disease caused by the Variola major virus. Worldwide immunization stopped the spread of smallpox three decades ago. The last case was reported in 1977.
Smallpox spreads very easily from person to person. Symptoms are flu-like and include high fever, fatigue and headache and backache, followed by a rash with flat red sores.

Smallpox (also known by the Latin names Variola or Variola vera) is a contagious disease unique to humans. Smallpox is caused by either of two virus variants named Variola major and Variola minor. The deadlier form, V. major, has a mortality rate of 30鈥?5%, while V. minor causes a milder form of disease called alastrim and kills ~1% of its victims. Long-term side-effects for survivors include the characteristic skin scars. Occasional side effects include blindness due to corneal ulcerations and infertility in male survivors.
A massive program by the World Health Organization (WHO) eradicated all known smallpox viruses from the world in 1977, except for samples that were saved by various governments for research purposes. The vaccine was discontinued in the United States in 1972. In 1980, WHO recommended that all countries stop vaccinating for smallpox.
Please see the web pages for more details on Smallpox.