Smallpox clinical presentation

CDC Case Definition An illness with acute onset of fever >101°F followed by a rash characterized by firm, deep seated vesicles or pustules in the same stage of development without other apparent cause. Clinically consistent cases are those presentations of smallpox that do not meet this classical clinical case definition (1) hemorrhagic type, (2) flat type, and (3) variola sine eruptione. Laboratory criteria for diagnosis is (1) polymerase chain reaction (PCR) identification of variola DNA in a clinical specimen, or (2) isolation of smallpox (variola) virus from a clinical specimen (Level D laboratory only confirmed by variola PCR). 

The recommendations state that hospitals should vaccinate enough staff in each category to ensure continuity of care (32). Health care workers performing the vaccinations should first receive the vaccine to minimize the consequences of inadvertent inoculation. Laboratory workers are not included in the recommendations because the quantity of smallpox virus likely to be present in clinical specimens is low. 

There are two clinical forms of smallpox. Variola major is the severe and most common form of smallpox, with a more extensive rash and higher fever. There are four types of variola major smallpox ordinary (the most frequent type, accounting for 90% or more of cases) modified (mild and occurring in previously vaccinated persons) flat and hemorrhagic (both rare and very severe). Historically, variola major has an overall fatality rate of about 30% however, flat and hemorrhagic smallpox usually are fatal. Variola minor is a less common presentation of smallpox, and a much less severe disease, with death rates historically of 1 % or le.ss. 

William J. Broad and Judith Miller, Government Report Says 3 Nations Hide Stocks of Smallpox, New York Times, June 13,1999, pi. Smallpox vaccinations for the US military were mentioned as late as in a 1990 article, but were no doubt superceded by publication date. Ernest T.Takafuji and Philip K. Russell, Military Immunizations Past, Present, and Future Prospects, Infectious Disease Clinics of North America, M2o ch 1990, p. 151. 

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