being more superficial, may occur either naturally or because of vaccination that was not recent enough to give complete protection against the disease. With nearly complete vaccinal protection, few lesions will appear; but even if vaccination has been effected many years before, smaller and more superficial lesions are the rule in cases in which an unvaccinated person would have a severe attack. Such superficial lesions are also characteristic of the naturally occurring mild strains of the disease (variola minor).Besides the characteristic focal eruptions (papule to vesicle to pustule to scab to scar), there is sometimes a toxic eruption during the initial fever, before the appearance of the true smallpox rash. These toxic rashes may be diffuse blushes on trunk or limbs, somewhat suggestive of scarlet fever or measles; they may, on the other hand, be deeper red, with small hemorrhages like fleabites or larger blotches in the skin. The first type of rash is clinically unimportant, but the deep red, hemorrhagic rash occurs in the most severe, usually fatal cases of the disease. Frequently such patients die before the true smallpox rash has time to develop, and the disease is not diagnosed. These cases are not usually sources of infection, however, because smallpox is not infectious until the characteristic focal eruption comes out in the throat and on the skin.Each case of smallpox arises from contact, direct or indirect, with another case of the disease. There are no natural animal carriers or natural propagation of the virus outside the human body. The virus is very stable and can survive for long periods outside the body. It has survived in bales of cotton for 18 months; because of this longevity clothing or bed linens contaminated by a smallpox patient can be a source of infection, and in outbreaks in Europe this means has often been shown to have spread the disease. The virus can also survive dried in dust, probably for several mon...
