Smallpox D GOLDBERG PED ID SVCE WRAMC SMALLPOX

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 formsvariola major-Europe/Asia variola minor-19 th 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

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 Prodrome: Rash: Lesions: Distribution: Stage: Smallpox 2 -4 days 1 -2 days deep/tense centrpetal (truncal) same Varicella 1 -2 days several days superficial centrifugal (face/extremeties) new crops

SMALLPOX Chickenpo x 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

SMALLPOX • Vaccinationlimited stock (6 million/ ? dilution) untrained administrators Special risk groups immunosuppressed/ pregnant women/eczema limited Vaccina IG (VIG) side effects

SMALLPOX-Vaccine complications * 70% children with fever > 39 C day 4 -14

SMALLPOX-Autoinoculation