January 2003 Variola Virus Photo Courtesy of CDC/Public Health Image Library 1

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January 2003 Variola Virus Photo Courtesy of CDC/Public Health Image Library 1 Slide 2 January 2003 History Ancient scourge many millions killed Global eradication in 1977 Slide 3 January 2003 Photo Courtesy of National Archives Slide 4 January 2003 Photo Courtesy of World Health Organization 2 Slide 5 January 2003 Bioweapon Potential Precedence Prior use in French-Indian War Produced by USSR Slide 6 January 2003 Bioweapon Potential Reality of the risk Viral stocks exist Non-immune population Slide 7 January 2003 Photo Courtesy of CDC 3 Slide 8 January 2003 Epidemiology No animal reservoir/vector Mortality 25-30% Person-to-person transmission Via respiratory droplets Household and face-to-face contacts High risk of nosocomial spread Secondary attack rate 25-40% Up to 20 contacts infected per case Slide 9 January 2003 Photo Courtesy of World Health Organization 4 Slide 10 January 2003 Epidemiology Aerosol route of transmission Likely in bioterrorism setting Slide 11 January 2003 Virology Orthopoxviridae DNA Viruses Variola variants Variola major high mortality Variola minor low mortality, 20 th Century Vaccinia Current smallpox vaccine Slide 12 January 2003 Virology Orthopoxviridae DNA Viruses Other pox viruses Cowpox Monkeypox Slide 13 January 2003 Pathogenesis Virus contacts respiratory mucosa Carried to lymph nodes Primary viremia Organ seeding WBCs infected Dermal invasion Vesicle Sepsis Slide 14 January 2003 Clinical Features Incubation Stage Asymptomatic 10-12 days (range 7-17) Slide 15 January 2003 Clinical Features Prodromal Stage Sudden nonspecific flu-like illness High fevers Headache Backache Prostration 2-5 days duration Slide 16 January 2003 Clinical Features Eruptive Stage Characteristic rash Centrifugal location Grouping Depth of lesions Slide 17 January 2003 Photo Courtesy of World Health Organization 5 Slide 18 January 2003 Clinical Features Distribution of the rash Slide 19 January 2003 Photo Courtesy of World Health Organization 6 Slide 20 January 2003 Photo Courtesy of World Health Organization 7 Slide 21 January 2003 Photo Courtesy of National Archives Slide 22 January 2003 Photo Courtesy of National Archives Slide 23 January 2003 Photo Courtesy of World Health Organization 8 Slide 24 January 2003 Photo Courtesy of World Health Organization 9 Slide 25 January 2003 Photo Courtesy of World Health Organization 10 Slide 26 January 2003 Photo Courtesy of World Health Organization 11 Slide 27 January 2003 Photo Courtesy of World Health Organization 12 Slide 28 January 2003 Photo Courtesy of World Health Organization 13 Slide 29 January 2003 Photo Courtesy of World Health Organization 14 Slide 30 January 2003 Photo Courtesy of World Health Organization 15 Slide 31 January 2003 Photo Courtesy of World Health Organization 16 Slide 32 January 2003 Photo Courtesy of World Health Organization 17 Slide 33 January 2003 Photo Courtesy of CDC/James Hicks 18 Slide 34 January 2003 Photo Courtesy of CDC 19 Slide 35 January 2003 Clinical Features Severity of the classical rash Discrete ( January 2003 Post-Exposure Prophylaxis Vaccine Protective within 3-4 days of exposure Reduces incidence 2-3 fold Decreases mortality >50% Cidofovir Effective vs other poxviruses Nephrotoxic antiviral agent Slide 72 January 2003 Vaccination Vaccinia live virus vaccine U.S. stock >20 years old, still viable 10 fold dilution still >95% effective Jennerian pustule = protection Photo Courtesy of CDC 41 Slide 73 January 2003 Vaccination Efficacy 10 fold reduction 2 o attack rate Full protection for 3-10 years Modest protection from mortality up to 20 yr Multiple vaccinations boost duration Slide 74 January 2003 Vaccination Adverse Effects 3/100,000 vaccinees Death 1/million vaccinees historically Highest risk Infants Primary vaccinees Absolute contraindications None in outbreak setting Slide 75 January 2003 Vaccination Relative contraindications Age January 2003 Infection Control Management of Case Contacts Period of infectiousness Oral lesions all scabs Fever precedes rash Fever Isolation Contact identification Exposure to case after fever onset Face-to-face contact < 3 meters Immediate vaccination 17 day observation Isolate if > 38 o Slide 80 January 2003 Infection Control Nosocomial transmission All patients and staff in hospital with a case should be vaccinated Quarantine may be necessary