What Is Variola Major?

Variola major belongs to the Poxviridae family of viruses and is also known as smallpox. The infectious disease was reported eradicated in 1980, though lab cultures still exist. Symptoms of the disease may not appear for up to 17 days after exposure and include systemic and topical characteristics. Patients suffering from the disease generally receive supportive treatment during hospitalization. Vaccination usually prevents the infections from spreading to otherwise healthy people and also may minimize the symptoms of those infected.

Individuals generally acquire variola major by inhaling the virus or coming in contact with body fluids containing the virus. Once in the nasal passages, the virus typically travels through the respiratory tract and into the lymph and blood, where it rapidly replicates. Major symptoms of variola major typically involve flu-like complaints that include a fever of up to 104 degrees Fahrenheit (40 degrees Celsius), nausea, vomiting, headaches, and general feelings of illness. Individuals may also experience muscle aches and stiffness, and 15% of the victims suffer some form of delirium.

After two or three days from the time of exposure, patients typically experience the formation of a pustule type rash. Unlike chickenpox, the lesions erupt all at once and seem confined to the face, limbs and upper chest. Pustules may also develop throughout the respiratory tract. The flu-like symptoms usually continue throughout the course of the disease. Approximately two weeks after the lesions appear scab formation occurs.

It is not unusual for the lesions to leave permanent pock mark type scars. People having the disease remain infectious from the time symptoms emerge until the body sheds the scabs. This may take two weeks or longer. Positive identification of the disease generally involves using the enzyme linked immunoassay (ELISA) and/or the polymerase chain reaction (PCR) test. ELISA checks for specific antibodies, while PCR allows researchers to replicate the virus DNA for positive identification through fingerprinting or mapping.

Supportive care is usually the only method of treating variola major and generally includes electrolyte and fluid maintenance. Patients may receive antibiotics when secondary infections develop. Mortality rates vary with deaths occurring in 3% of the vaccinated population and roughly 30% in patients without prior immunization. Vaccinations may contain the live virus or provide passive protection with vacinia immunoglobulin serum (VIG).

The variola major smallpox may also transform into more severe forms of the disease known as black or hemorrhagic smallpox. Variola minor is a less severe type of smallpox, with mortality rates generally as low as 1%. This variation of the illness is also commonly referred to as cotton pox, milk pox, or white pox.