Variola Virus
Morphology | Family: Poxviridae; Subfamily: Chordopoxvirinae Genus: Orthopoxvirus. Virions are shaped like bricks on electron micrographs and measure approx. 300 x 250 x 200 nm. Orthopoxviruses have an outside envelope and a second membrane underneath. Instead of a capsid, poxviruses have a nucleosome which contains DNA, and is surrounded by its own membrane. They contain single, linear, doublestranded DNA molecules of 130 to 375 kb pairs and replicate in the cell cytoplasm |
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Growth Conditions | Vero monkey kidney cells and a human fibroblast cell line (MRC5). |
Host Range | Humans and monkeys |
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Modes of Transmission | Transmission occurs via respiratory droplets (primary route of transmission), or via fine-particle aerosol, or skin inoculation. The conjunctiva or placenta may be occasional portals of entry. Respiratory droplets (i.e., coughing, sputum, and saliva) have a range of likely no more than 2 meters and are, therefore, a threat only to persons in the immediate vicinity of the affected patient |
Signs and Symptoms |
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Infectious Dose | Viruses in an aerosol suspension can spread widely, and infect at a very low dose (10 to 100 organisms) |
Incubation Period | Duration: 7 to 17 days Not contagious |
Prophylaxis | None available. |
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Vaccines | Live vaccinia virus every 3 yr. Full protection occurs after successful vaccination. Vaccination at 4 to 7 days after exposure likely offers some protection from disease or may modify the severity of disease. |
Treatment | None |
Surveillance | Monitor for symptoms and confirm using PCR, electron microscopy and histology. |
Emory Requirements | Report all incidents. |
Laboratory Acquired Infections (LAIs) | Except for a laboratory-associated smallpox death at the University of Birmingham, England, in 1978, no further cases have been identified. |
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Sources | s Lesion fluids or crusts, respiratory secretions and infected tissues containing the virus. |
Canadian MSDS | |
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CDC Guidelines |
BSL-4/ABSL-4 | Containment Level 4 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures. |
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Small | Notify others working in the lab. Allow aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply an EPA registered disinfectant, working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials. |
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Large | Contact Emory’s Biosafety Officer (404-727-8863), |
Mucous membrane | Flush eyes, mouth or nose for 15 minutes at eyewash station. |
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Other Exposures | Wash area with soap and water for 15 minutes. |
Reporting | Immediately report incident to supervisor, complete an employee incident report in PeopleSoft. |
Medical Followup | 7am-4pm (OIM): EUH (404-686-7941) EUHM (404-686-7106) WW (404-728-6431) After Hours: OIM NP On Call 404-686-5500 PIC# 50464 Needle Stick (OIM): EUH (404-686-8587) EUHM (404-686-2352) Yerkes: Maureen Thompson Office (404-727-8012) Cell (404-275-0963) |
Disinfection | 70% Ethanol, sodium hypochlorite (1-10% dilution of fresh bleach). If using bleach within a biosafety cabinet, always follow up with a 70% ethanol rinse |
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Inactivation | Can be inactivated by heat: autoclave cultures for 30 minutes at 121°C, 15 psi or by incineration. |
Survival Outside Host | Materials from smallpox patients (dried fluid and crusts) containing virus remain infectious at room temperature for approximately 1 year. |
Minimum PPE Requirements | See PPE matrix developed for healthcare personnel attending potentially infectious or confirmed patients |
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