Reasonable Rascal
09-02-01, 20:37
SMALLPOX
CLINICAL FEATURES
The incubation period of smallpox averages 12 days, and contacts should be quarantined for a minimum of 16-17 days following exposure. A small percentage of cases may develop delirium.
Following breakout on the lower extremities, the rash spreads to the chest and back over the next week. The characteristic "pustules" progress quickly and are more abundant on the extremities and face. This characteristic of smallpox is an important diagnostic trait in that it differs significantly in the way it spreads from other forms of pox infections. The scabs that form often leave pitted scars that lack the normal skin pigmentation. Patients should be considered infectious until ALL scabs have dropped away of their own accord.
Looking back 100 years or so two distinct types of smallpox are recognized. Variola Minor was distinguished by milder general toxicity and more smaller pox lesions, and caused 1% mortality in unvaccinated victims. However the more dreaded Variola Major caused mortality of 3% and 30% in the vaccinated and unvaccinated, respectively. A naturally occurring relative of Variola - Monkeypox - occurs in Africa, and is not normally distinguishable from smallpox with the exception of notable enlargement of lymph nodes in the neck and crotch (inguinal) areas.
MEDICAL MANAGEMENT
The possibility of airborne spread to other than close contacts is arguable. Normally close person-to-person proximity is required for transmission to occur reliably.
Vaccination with a verified "take" (blister with scar formation later) within the past 3 years is considered to render a person immune to smallpox. Notice the 3 years. Childhood vaccinations in the 60's and 70's would confer only limited protection at best. Immunity is not conferred for life.
Antiviral drugs for uses against smallpox are under investigation. Cidofovir has been shown to have significant effect, but is of course an Rx only and like all antiviral drugs very expensive.
SUMMARY
Signs and Symptoms: Clinical signs begin with acute (sudden) onset with malaise, fever, rigors, vomiting, headache, and backache. 2-3 days later lesions appear which quickly progress from spots to raised spots to blister-like pus-laden sores. They are more abundant on the extremities and face, and develop in series, that is on one part of the body and progress from there, normally beginning with the legs.
Treatment: At present there is no effective drug therapy aimed specifically at curing the patient of smallpox and treatment remains supportive.
Prophylaxis (prevention): With the current lack of vaccine available to civilians avoidance is the only preventive measure. Taking antibiotics will not prevent it.
Isolation and Decontamination: Droplet and Airborne Precautions for a minimum of 16-17 days following exposure for all contacts. Patients should be considered infectious until all scabs separate. For decontamination a strong solution of common household bleach (sodium hypochlorite) is a minimum consideration for all surfaces, linens, etc.
The United States stopped vaccinating its military population in 1989 and civilians in the early 1980s. These populations are now susceptible, although recruits immunized in 1989 may retain some degree of immunity.
CLINICAL FEATURES
The incubation period of smallpox averages 12 days, and contacts should be quarantined for a minimum of 16-17 days following exposure. A small percentage of cases may develop delirium.
Following breakout on the lower extremities, the rash spreads to the chest and back over the next week. The characteristic "pustules" progress quickly and are more abundant on the extremities and face. This characteristic of smallpox is an important diagnostic trait in that it differs significantly in the way it spreads from other forms of pox infections. The scabs that form often leave pitted scars that lack the normal skin pigmentation. Patients should be considered infectious until ALL scabs have dropped away of their own accord.
Looking back 100 years or so two distinct types of smallpox are recognized. Variola Minor was distinguished by milder general toxicity and more smaller pox lesions, and caused 1% mortality in unvaccinated victims. However the more dreaded Variola Major caused mortality of 3% and 30% in the vaccinated and unvaccinated, respectively. A naturally occurring relative of Variola - Monkeypox - occurs in Africa, and is not normally distinguishable from smallpox with the exception of notable enlargement of lymph nodes in the neck and crotch (inguinal) areas.
MEDICAL MANAGEMENT
The possibility of airborne spread to other than close contacts is arguable. Normally close person-to-person proximity is required for transmission to occur reliably.
Vaccination with a verified "take" (blister with scar formation later) within the past 3 years is considered to render a person immune to smallpox. Notice the 3 years. Childhood vaccinations in the 60's and 70's would confer only limited protection at best. Immunity is not conferred for life.
Antiviral drugs for uses against smallpox are under investigation. Cidofovir has been shown to have significant effect, but is of course an Rx only and like all antiviral drugs very expensive.
SUMMARY
Signs and Symptoms: Clinical signs begin with acute (sudden) onset with malaise, fever, rigors, vomiting, headache, and backache. 2-3 days later lesions appear which quickly progress from spots to raised spots to blister-like pus-laden sores. They are more abundant on the extremities and face, and develop in series, that is on one part of the body and progress from there, normally beginning with the legs.
Treatment: At present there is no effective drug therapy aimed specifically at curing the patient of smallpox and treatment remains supportive.
Prophylaxis (prevention): With the current lack of vaccine available to civilians avoidance is the only preventive measure. Taking antibiotics will not prevent it.
Isolation and Decontamination: Droplet and Airborne Precautions for a minimum of 16-17 days following exposure for all contacts. Patients should be considered infectious until all scabs separate. For decontamination a strong solution of common household bleach (sodium hypochlorite) is a minimum consideration for all surfaces, linens, etc.
The United States stopped vaccinating its military population in 1989 and civilians in the early 1980s. These populations are now susceptible, although recruits immunized in 1989 may retain some degree of immunity.