Infectious Disease Project: Small Pox

Symtoms

There are four types of variola major smallpox based on the Rao classification: ordinary, modified, flat, and hemorrhagic. Historically, variola major has an overall fatality rate of about 30%; however, flat and hemorrhagic smallpox are usually fatal. Smallpox cuases an extensive rash and a higher fever.

 Ordinary:By the third or fourth day the papules fill with an opalescent fluid to become vesicles. This fluid becomes opaque and turbid within 24–48 hours, giving them the appearance of postules; however, the so-called pustules are filled with tissue debris, not pus.By the sixth or seventh day, all the skin lesions have become pustules. Between 7 and 10 days the pustules mature and reach their maximum size. The pustules are sharply raised, typically round, tense, and firm to the touch. The pustules are deeply embedded in the dermis, giving them the feel of a small bead in the skin. Then the puss starts to leak out and scabs begin to form.By day 16-20 scabs have formed over all the lesions, which have started to flake off, leaving de-pigmented scars.Ordinary smallpox generally produces a discrete rash, in which the pustules stand out on the skin separately.In some cases, the blisters merge together into sheets, forming a confluent rash, which begin to detach the outer layers of skin from the underlying flesh.

 Modified:There is usually no fever during evolution of the rash. The skin lesions tend to be fewer and evolve more quickly, are more superficial, and may not show the uniform characteristic of more typical smallpox. Modified smallpox is rarely, if ever, fatal. This form of variola major is more easily confused with chickenpox.

 Flat:Flat smallpox is accompanied by a severe prodominal phase that lasts 3–4 days, prolonged high fever, and severe symptoms of toxemia.The skin lesions mature very slowly and by the seventh or eighth day the lesions are flat and appear to be buried in The skin lesions mature very slowly and by the seventh or eighth day the lesions are flat and appear to be buried in the skin. Unlike ordinary-type smallpox, the vesicles contain very little fluid, are soft and velvety to the touch, and may contain hemorrhages. Flat-type smallpox is nearly always fatal.the skin. Unlike ordinary-type smallpox, the vesicles contain very little fluid, are soft and velvety to the touch, and may contain hemorrhages. Flat-type smallpox is nearly always fatal.

 Hemmorhagic:Hemorrhagic smallpox is a severe form of smallpox that is accompanied by extensive bleeding into the skin, mucous membranes, and gastrointestinal tract. This form developed in perhaps 2% of infections and occurred mostly in adults. In hemorrhagic smallpox the skin does not blister, but remains smooth. Instead, bleeding occurs under the skin, making the skin look charred and black.Hemorrhagic smallpox also produces a dusky erythema, petechiae, and hemorrhages in the spleen, kidney, serosa, muscle, and, rarely, the epicardium, liver, testes, and bladder. Death often occurs suddenly between the fifth and seventh days of illness, when only a few insignificant skin lesions are present. A later form of the disease occurs in patients who survive for 8–10 days. The hemorrhages appear in the early eruptive period, and the rash is flat and does not progress beyond the vesicular stage.(Amanda)

Number of people infected each year

-Http://www.cnn.com/health/library/ds/00424.html

-http://www.cfr.org/publication/9554/

-http://www.wrongdiagnosis.com/s/smallpox/symptoms.htm

-http://www.bioterrorism.uab.edu/categoryA/smallpox/smallpox_images.jpg

-http://www.cdc.gov/Features/Smallpox.Eradication/Smallpox.Eradification