Variola Minor is also known as Variola alastrim and is another virus that causes smallpox. Smallpox is most often spread by the respiratory secretions of people with smallpox to people who have close face to face contact. Less often it is spread through direct contact with smallpox lesions of the skin and mucous membranes, or through contact with materials contaminated by such lesions or scabs.
There are two types of smallpox:
- variola major
- variola minor
Variola major is the more severe form and has a 30-50% fatality rate among those who are unvaccinated. Variola minor has a 1-2% fatality rate in unvaccinated individuals.
The variola virus causes smallpox. Under high magnification, variola particles look like rectangles with a deeply patterned surface. The sometimes referred to as bricks. Each brick is composed of at least a hundred different proteins. Sometimes a person came into contact with someone with skin lesions caused by the disease. Skin lesions are wounds produced by the virus. They were known as pox. A person also could catch the virus even if the infected person had no lesions.
The virus usually entered the body through the respiratory tract. It then passed through an incubation period of twelve to fourteen days. An incubation period is the time that passes after a person is infected before symptoms appear. During this time, the virus was multiplying within the body and moving through the bloodstream.
Variola minor, like variola major, is highly infectious and could be spread through inhalation of the virus released from lesions into nasal secretions, and also through direct contact of scab material, though at a much lower rate of transmission. The virus enters through the respiratory tract, grows on mucous membranes, and spreads to regional lymph nodes where it multiplies before entering the bloodstream. Fever and other symptoms appear at this time. A rash follows that spreads and progresses to raised bumps that crust, scab, and fall off after about three weeks, leaving a pitted scar.
If a diagnosis of smallpox were made, exposed persons would need to be isolated immediately. The isolation would include not just the person who contracted the disease, but all other face-to-face contacts with that person.
One of the best ways to prevent smallpox is through vaccination. If given to a person before exposure to smallpox, the vaccine can completely protect them. Vaccination within 3 days after exposure will prevent or greatly lessen the severity of smallpox in most people.
Immunity is most effective during the first 10 years after vaccination and decreases thereafter. Historically, the vaccine has been effective in preventing smallpox infection in 95% of those vaccinated. The level of protection, in people whom received the last routine smallpox vaccination over 30 years ago, is unclear.