Smallpox, a highly infectious disease caused by the variola virus, has been eradicated globally now. This highly infectious disease is a deadly disease and leaves permanent scars in the affected areas of the skin. Smallpox usually causes high fever, headache, backache, severe body ache, and scars. Blisters appear over the face, forehead, and hands after a few days of high-grade fever. After around eight or nine days these blisters leave scars that are sometimes permanent. The scars are usually very deep leading to disfigurement. Any blister near the eye can be a real threat as it may cause blindness. Normally scars due to smallpox do not vanish over time. In some persons, the scars spread to the whole body.
 

This infectious disease spreads by air when the affected person sneezes. Contact with the infectious person and its clothing is also a threat. A vaccine for smallpox was mandatory worldwide for preventive measures. Smallpox had been a threat to human health in the early 19th century. By 1980, with the help of the smallpox vaccine, this infectious disease was eradicated completely. The vaccine developed for smallpox was for preventive purposes only and was not a cure. The vaccine developed for this infectious disorder is a live vaccine. This vaccine can stimulate the immune system and generate antibodies against smallpox. This vaccine is administered to people who have come in contact with an infected person. Small pox vaccine usually leaves a scar at the area of vaccination. This is due to local inflammatory reaction at that place. As smallpox is not a threat these days, this vaccine is not recommended as a preventive measure. Smallpox vaccine can lessen the severity of the disease but has side effects as well. Smallpox vaccine can, in some cases, cause encephalitis which can lead to convulsions. This infectious disorder has no cure.
 

Smallpox is a real threat for pregnant women and persons with compromised immune systems. The scars can be quite disfiguring and a social stigma for persons affected with this infectious disease. This disease is confirmed by analyzing a tissue sample from the infected person. Even a single confirmed case of this infectious disease can be a threat to the whole of humanity. The preserved smallpox virus is actually a threat as it can be used for bioterrorism. Otherwise, this infectious disease is not a real threat to humanity now since it is eradicated.