Smallpox

All suspect cases of Smallpox must be reported immediately to Public Health, Communicable Disease Control:

During business hours: 925-313-6740
After hours (County Communications):925-646-2441

Highly infectious after aerosolization
Person-to-person transmission can occur via droplet nuclei or aerosols expelled from the oropharynx and by direct contact
Contaminated clothing or bed linens can also spread the virus
About 30% of susceptible contacts will become infected

Incubation period is 12-14 days (ranges 7-17 days)
Characteristic rash appears 2-3 days after nonspecific, flu-like prodrome (fever and headache)
Maculopapular rash begins on mucosa of mouth and pharynx, face, hands, forearms and spreads to legs and centrally to trunk; lesions are more predominant on the face and extremities than on the trunk.
Lesions progress synchronously on any given part of the body from macules to papules to vesicles to pustules to crusty scabs

Mask and gloves should be worn by person obtaining specimen, preferably a person who has been recently vaccinated
Vesicular fluid is obtained by opening lesions with the blunt edge of a scalpel, harvesting fluid with a cotton swab; scabs can be removed by forceps. Swabs and scabs should be placed in a vacutainer, sealed with tape, and placed in a second, durable, watertight container
Laboratory specimens must be handled in a Biosafety Level 4 facility (e.g. CDC) and will be evaluated with electron microscopy and cell culture

Strict isolation in negative pressure room (high efficiency particulate air filtration ideal) from onset of rash until all scabs separate
Laundry and waste should be autoclaved before being laundered or incinerated

Supportive care is the mainstay of therapy
In-vitro antiviral activity against poxviruses has been shown with adefovir, cidofovir, dipivoxil, and ribavirin. (Animal studies suggest that cidofovir may be most effective).

Smallpox vaccine would be required for all persons exposed at the time of the bioterrorist attack or anyone with close personal contact with a smallpox case
Vaccine is most effective if given before of within 3 days of exposure
Ideally, all exposed persons should be placed in strict quarantine for 17 days after last contact with a smallpox case

(From the New England Journal of Medicine)

For more detailed information, Please call 925-313-6740 or email Francie Wise, Director of Communicable Disease

Thanks to Santa Clara County for information provided on this page.

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Content provided by the Public Health Division of Contra Costa Health Services.