Smallpox is a virus diseases which is highly contagious, disfiguring and often fatal. Fortunately following worldwide immunization campaigns this naturally-occurring disease has been eradicated. However, there are laboratories which stockpile the virus for research purpose, as it is sometimes feared to be used as a biological weapon. There is no treatment available for smallpox virus but vaccines can prevent it. The risks associated with vaccination is major so routine vaccination is not recommended and not usually necessary as the naturally-occurring disease has been eradicated.

The disease causes characteristic raised fluid-filled skin rashes which may complicate into scars, blindness, deformed limbs and the disease is fatal in nearly 30 to 35% of cases. Smallpox used to be one of the most deadly diseases known to mankind. WHO estimated that as recently as in 1967 it killed about 2 million people worldwide. It is no longer as much a concern these days but with the risk of bioterrorism, it should not be forgotten as a possible health threat.


It takes usually 12 days after contracting the infection and manifestation of the first symptom. The common symptoms are divided into phases :

  • Prodromal or preeruptive stage :
    – Fever reaching about 101◦F
    – Muscle ache and entire body ache
    – Headache
    – Tiredness
    – Nausea and vomiting
  • Papular phase :
    – Rashes of smallpox usually appear by 12 to 15 days on the mouth, tongue and palate, and when these lesions rupture they release large amount of virus in the saliva.
    – Skin rashes appear within 24 to 48 hours after the mucosal rashes. Most commonly the rash first appear on the forehead then spread to other body parts like the trunk and the extremities. The rashes appear for about next 24 to 36 hours after which no new rash appears. The skin rashes of small pox is usually of four types ordinary – modified, malignant and hemorrhagic of which the last two forms are highly fatal.

Once the scabs resolve, the person is no longer contagious.

  1. Ordinary smallpox is the most common type of smallpox infecting about 90% patients. The rashes are more common on the face. Sometimes smaller blistering lesions may merge together forming larger lesion causing confluent small pox. People suffering from confluent lesions may remain ill even after disappearance of the lesions.
  2. Modified type of lesions are seen in person who were previously vaccinated.
  3. Malignant or flat variety of small pox lesions remain almost flushed with the skin, there is high fever and the lesions instead of clear fluid may contain blood.
  4. Hemorrhagic lesions usually occurred in adults and characterized by bleeding under the skin making it look black, even bleeding in the conjunctiva or inner organs like kidney or spleen and this kind of small pox is usually fatal.


Smallpox occurs due to infection with the variola virus. The disease is transmitted from one person to another through airborne particles but contact with body fluids and contact with regular items like beddings and clothes can also spread the virus. The disease occurs throughout the year although it is more common during winter and spring and can affect any age group. Naturally-occurring smallpox has been eradicated but people who work in the laboratories stocking the virus may be at risk.


There is no cure for smallpox apart from vaccination to prevent it. Proper fluid replacement along with nutritious diet would be helpful along with antibiotics for secondary infection.

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