Smallpox Symptoms

A Quick Guide To Smallpox Symptoms

While there has not been a known case of smallpox in the world since 1978, it remains important to have a general knowledge of smallpox symptoms. The global eradication of smallpox was declared in 1979 and endorsed by the World Health Assembly the following year, but the virus still exists in laboratories in the United States and Russia. Although once scheduled to be destroyed, the World Health Organization has decided that the remaining samples of the virus should be maintained for potential research purposes. Fears remain among some that the existing stock of smallpox virus will be weaponized and used as an agent of biological warfare. Whether smallpox recurs naturally or as a weapon, knowing the symptoms of smallpox can help to identify the virus early and keep a recurrence from rising to epidemic proportions.

After becoming infected with smallpox, symptoms generally appear within twelve to fourteen days. During this time, the incubation period, a person infected with smallpox will continue to look and feel healthy and is not contagious to others. Initial smallpox symptoms are similar to the flu: a fever of at least 101 degrees Fahrenheit, muscle pain and overall discomfort, headache, severe fatigue, and in some cases nausea and diarrhea. These initial symptoms will last two to four days, and be followed by the rash that characterizes smallpox.

At the time of the rash's appearance, fever will subside and body temperature will return to near normal. The smallpox rash begins as small and flat red spots known as lesions, appearing on the mucous membranes in the mouth and nose. The infected individual is at his or her most contagious when these lesions slough off and release the smallpox virus into the saliva. Approximately one to two days after the lesions appear on the mucous membranes, the rash will spread to the skin of the face, hands and arms, and later to the trunk. The lesions are particularly noticeable on the palms of the hands and soles of the feet. This distribution of the smallpox rash is an important feature of the virus, and is one of the simplest ways to distinguish between smallpox and chickenpox. The chickenpox rash occurs primarily on the trunk rather than the extremities, and is very rarely found on the palms and soles. The lesions take 24 to 36 hours to finish appearing on the skin; after this time further lesions will not appear.

During the following six or seven days, the smallpox lesions will undergo a series of changes. They become raised and form blisters that are filled with a clear fluid, called vesicles. Within another day or two, the fluid inside the vesicles becomes opaque as they fill with tissue debris, forming pustules. Fever may recur as the pustules form.

By two weeks after the initial presentation of smallpox symptoms, the pustules will have reached their largest size. At this point the skin of the pustules separates from the underlying layers and they erupt, leaking fluid; this is an extremely painful process. Scabs will form over the pustules and eventually flake off, leaving deep scars. If a case of smallpox proves fatal, as is the case approximately 30 percent of the time, death usually occurs during the second week of smallpox symptoms.

Rarely, a person may develop flat or hemorrhagic smallpox. In both cases, the smallpox lesions do not become raised. In flat smallpox, the vesicles are slow to develop and remain soft to the touch. It can result in the sloughing of large areas of skin and is often fatal. Hemorrhagic smallpox is the most severe form, and causes extensive bleeding in internal organs and under the skin. This type of smallpox is nearly always fatal within one week of the first smallpox symptoms.