The most important step in confirming a case of smallpox is
laboratory diagnosis. Someone who has recently been vaccinated
and who wears gloves and a mask must collect the specimens.
To obtain vesicular or pustular fluid, it is often necessary
to open lesions with the blunt edge of a scalpel. The fluid
can then be harvested on a cotton swab. Scabs can be picked
off with forceps. Specimens should be deposited in a primary
sterile vacutainer tube sealed with tape, packed with absorbent
padding in a secondary "screw-top" container and then in a United
Nations approved shipping carton, in accordance with 49CFR172.
See www.iata.org and www.dot.org for additional information on
shipment of diagnostic specimens and etiologic agents.
As always, state or local health department laboratories
should immediately be contacted regarding the shipping of
specimens. Laboratory examination and diagnosis requires
high-containment (Biosafety Level-4) facilities and should be
undertaken only in designated laboratories where appropriately
trained personnel and equipment are available.
Smallpox infection can be rapidly confirmed in the laboratory by
electron microscopic examination of vesicular or pustular liquid or scabs.
Definitive laboratory identification and characterization of the virus
involves growth of the virus in the cell culture or on chorioallantoic
egg membrane and characterization of strains by use of biologic assays,
including the polymerase chain reaction (PCR), restriction fragment-length
polymorphism analysis (RFLP) and ELISA. Confirmation using these methods can
be accomplished in a few hours.
Contents: Smallpox (Extensive Information)
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