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 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 (103 0 ), HA, prostation, bachache, malaise, +/- abd pain, delerium, rash by day 3 Rash-macularpapular on oropharynx, face forearms-->trunk, legs -turns vesicular hrs - turns tense round pustules

SMALLPOX

SMALLPOX

SMALLPOX

SMALLPOX Secondary infection is rareSecondary infection is rare Death in second week due to toxemiaDeath in second week due to toxemia Variola minor-less severe symptoms, rashVariola minor-less severe symptoms, rash Vaccinated -milder formVaccinated -milder form HIV-? (Disseminated vaccina in HIV+ soldier in 1986)HIV-? (Disseminated vaccina in HIV+ soldier in 1986)

SMALLPOX- Laboratory Diagnosis Level BL-4 onlyLevel 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 Smallpox Varicella 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 Shingles

SMALLPOX-Therapy Cidofovir ? ?

SMALLPOX Postexposure Control-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

SMALLPOX Vaccination-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

SMALLPOX-Autoinoculation