After a 7 - 17-day incubation period, symptoms begin acutely with high fever, headache, chills, malaise, muscle pain, vomiting, abdominal and back pain. During the initial phase, 15% of patients become delirious
2-3 days later, lesions appear which quickly change into pus-filled blisters especially on the extremities and face. Patients are most infectious 3-6 days after the onset of fever. Virus is shed from the scabs and respiratory secretions.
How does it spread?
Smallpox spreads directly from person to person, primarily by
spray expelled from the back of the mouth of an infected person
or by aerosol.
Contaminated clothing or bed linen can also spread the virus. Special precautions need to be taken to insure that all bedding and clothing of patients are autoclaved. Disinfectants such as hypochlorite and quaternary ammonia should be used for washing contaminated surfaces.
Smallpox is usually diagnosed after looking at blister scrapings
under an electron microscope. Sometimes a modified silver stain
is used; however, these tests can't distinguish between smallpox,
monkeypox or cowpox. Smallpox is differentiated from chicken pox
by the centrifugal distribution of its rash and the presence of
lesions at the same stage of development everywhere on the body.
Strict quarantine with respiratory isolation for 17 days is applied
to all people in direct contact with the index case or cases.
People exposed to either weaponized smallpox or clinical cases must be vaccinated immediately. It's effective at lessening or preventing illness if done within a few days of exposure. Vaccinia immune globulin (VIG) is given to patients who cannot take the vaccine - like those with impaired immune systems, HIV infection, are pregnant, have a history or evidence of eczema OR, current household, sexual, or other close physical contact with person(s) possessing one of these conditions.
Specifics on treatment can be found here
No one in the U.S. has been vaccinated for the past 25 years. Vaccination ceased in this country in 1972. Anyone who was vaccinated before that time no longer has immunity.
Vaccination with a verified clinical "take" (vesicle with scar formation) within the past 3 years is considered immune to smallpox.
Smallpox vaccine (a weakened form of the virus) is administered which results in a permanent scar. A blister usually appears 5-7 days after inoculation which scabs over and heals over the next 1-2 weeks. Reactions include low-grade fever and enlarged lymph nodes.
Vaccinia immune globulin (VIG) can be obtained from the CDC and is administered at a dose of 0.6 mL/kg IM.
Two types of smallpox generally are recognized. Variola major,
the most severe form, has a fatality rate of 30% in unvaccinated
individuals and 3% in those previously vaccinated.
Variola minor, a milder form of smallpox, is lethal in only 1% of unvaccinated individuals.
Federation of American Scientists; http://www.fas.org/nuke/intro/bw/agent.htm
USAMRIID's Medical Management of Biological Casualties Handbood; Fourth Edition February 2001; pages 9-10; http://usamriid.detrick.army.mil/education/bluebook/bluebook.pdf
All contents © 2001 Stan and Holly Deyo. All rights reserved.
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