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Smallpox. D. GOLDBERG PED ID SVCE WRAMC. SMALLPOX. Genus Orthopoxvirus Smallpox, monkeypox, cowpox,vaccinia DNA Virus 200 nm brick shaped Smallpox-person to person spread via respiratory secretions/direct contact Spread best in low humidity/temperature . SMALLPOX. SMALLPOX.
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Smallpox D. GOLDBERG PED ID SVCE WRAMC
SMALLPOX • Genus Orthopoxvirus Smallpox, monkeypox, cowpox,vaccinia • DNA Virus • 200 nm brick shaped • Smallpox-person to person spread via respiratory secretions/direct contact • Spread best in low humidity/temperature
SMALLPOX • 2 principle forms- variola major-Europe/Asia variola minor-19th century USA • 2 minor forms-malignant & hemorrhagic • Spread via respiratory droplets/direct contact at time of rash • Historically spreads slower than chicken pox, measles
SMALLPOX-Pathogenesis • Incubation period (7-17 days): Virus infects respiratory/pharyngeal mucosa--> regional lymph nodes--> viremia-->spleen, bone marrow, lymph nodes-->second viremia--> fever, toxemia--> rash and infectivity
SMALLPOX-Pathogenesis • Clinical Stage- Onset fever (1030), HA, prostation, bachache, malaise, +/- abd pain, delerium, rash by day 3 Rash-macularpapular on oropharynx, face forearms-->trunk, legs -turns vesicular 24-48 hrs - turns tense round pustules
SMALLPOX • Secondary infection is rare • Death in second week due to toxemia • Variola minor-less severe symptoms, rash • Vaccinated -milder form • HIV-? (Disseminated vaccina in HIV+ soldier in 1986)
SMALLPOX- Laboratory Diagnosis • Level BL-4 only EM of fluid/scabs Culture/PCR Oropharyn swabs-day 7/8 of infection AB titers (day 6 of rash)
SMALLPOX- Clinical Diagnosis SmallpoxVaricella Prodrome: 2-4 days 1-2 days Rash: 1-2 days several days Lesions: deep/tense superficial Distribution: centrpetal centrifugal (truncal) (face/extremeties) Stage: same new crops
SMALLPOX Chickenpox Shingles
SMALLPOX-Therapy • Cidofovir ? • ?
SMALLPOX • Postexposure Control- Home care vs hospital care (neg pressure) Mass “contact” vaccination (up to 4 days post exposure may ameliorate/prevent) Vaccinated individuals serve as caretakers Cremation of bodies
SMALLPOX • Vaccination- limited stock (6 million/ ? dilution) untrained administrators Special risk groups immuno- suppressed/ pregnant women/eczema limited Vaccina IG (VIG) side effects
SMALLPOX-Vaccine complications * 70% children with fever > 39C day 4-14