SMALLPOX
Smallpox is caused by variola virus.
Smallpox was once among the deadliest of diseases afflicting humankind, killing millions of people in regular epidemics. Thanks to a worldwide vaccination drive, smallpox was effectively wiped out in 1980. Some officials are concerned, however, that terrorists may have obtained variola virus stored in laboratories in the U.S. and Soviet Union.
Smallpox is highly contagious and quite deadly. The most lethal form of smallpox, variola major, has a mortality rate of 30%, meaning that 3 of 10 people who contract the disease will die from it.
Smallpox is spread by face to face contact with someone who has smallpox, through exposure to their bedding or clothing, or through infected body fluids. Aerosol exposure is also possible, though not as likely since smallpox virus is killed by both sunlight and heat.
Symptoms appear within 7 to 17 days after exposure and include high fever, headache, lassitude, vomiting, rash on face and arms that spreads to the rest of the body. The rash turns into bumps and then pustules (raised sores) that crust and then scab over. Scabs fall off, leaving scars. Persons infected with smallpox are highly contagious from the time the rash appears until the last scab falls off.
Pre-exposure vaccination protects against smallpox completely. Vaccination within three days of exposure (i.e. before symptoms appear) may lessen the severity of the infection. Vaccination within 4 to 7 days afrer exposure may also decrease the severity of the disease. Vaccination is of no help to those who have already contracted a rash.
There is no treatment to cure for smallpox. Intravenous fluids, analgesics to control fever and body ache, and antibiotics to fight secondary bacterial infections may provide some relief until the disease runs its course.
Because smallpox is highly contagious, smallpox patients should be isolated using maximum precautions. Anyone who has had contact with a smallpox patient should be vaccinated immediately. These exposed persons in whom symptoms have not yet appeared may also be isolated during the incubation period.
