Home » Science & Nature » Molecular Biology/Medicine » SMALLPOX: HOW DANGEROUS IS IT?

SMALLPOX: HOW DANGEROUS IS IT?

© Juan C. Mendible

Do you really need a weapon deliver it?

A unknown number of years ago, perhaps between 3,000 and 12,000, a poxvirus made the jump from its natural host to man. It is now known as smallpox. And it is considered the worst and most dangerous bioweapon in the world. Why is that so?

For a person to be infected he or she must inhale the virus, which enters the respiratory tract and multiplies locally, probably within the macrophages which, by the way, are one segment of the first part of defense of the immune system.

From there the virus is carried through the body.

The incubation period -- that is, the time in which the first symptoms appear -- ranges between seven and 19 days, with a mean of 12. The symptoms start with a sudden onset of fever, headache, backache and malaise. At this point you realize that it can easily been confused with the flu.

The initial most characteristic symptom is the rash that first appears as minute red spots on the tongue and palate and small spots, macules, in the face. The spots spread centrifugally, that is, they go from the face to the arms, the trunk and the legs.

The rash in the mouth goes from lesions called papules by day two, vesicles by day four to five and pustules -- pus-filled lesions -- by day seven of the rash.

The vesicles are the most important source of virus contagion. Thus, two days after the person has been infected he or she can start to spread the virus. After day nine the pustules on the skin also start to spread virus.

As you can see, the infected person could be a source of virus much before it has been diagnosed with a disease. With the facility of transportation we have today, one person could be infected in one place today and start infecting people at the other side of the world two days later.

How many persons can one infect? That is impossible to say. It depends on the number of close contacts he had, how closed was the environment in which he was, how sick he is, etc., but you can imagine that the number could go much higher than 20.

The mortality of smallpox is calculated to be about thirty percent, so you could optimistically think that it does not seem too high. You are probably right, but, how do you stop the disease?

The copyright of the article SMALLPOX: HOW DANGEROUS IS IT? in Molecular Biology/Medicine is owned by . Permission to republish SMALLPOX: HOW DANGEROUS IS IT? in print or online must be granted by the author in writing.