Smallpox

From ArticleWorld

Smallpox is caused by two virus types, Variola major and Variola minor. V. major is the most dangerous form, killing between 20 and 40% of those affected. V. minor is less deadly, with a mortality rate as low as 1%. Many of those who survive V. major are left with several sequels, generally blindness in one or both eyes because of ulcerations appearing on the cornea.

In the 20th century alone, smallpox is estimated to have killed more than 300,000,000 people, but several successful vaccination campaigns led to its eradication in 1979. Vaccination was, however, quite dangerous, since it had several side effects, so most countries decided to stop it during the 70s. Nevertheless, smallpox is currently eradicated, with only a few cultures remaining in the Centers for Disease Control and Prevention in the US, and in Russia.

Smallpox is responsible for several major outbreaks in the history, including the Antonine Plague and a great Indian epidemic in the year 400 CE.

Symptoms and treatment

The virus is transmitted by face-to-face contact or direct contact with infected fluids or objects. Airborne transmission has been reported, but it is quite rare. The virus has a 12-day incubation period, after which symptoms begin to appear. The initial symptoms are similar to those of influenza, including fever, muscle and joint pain, and stomach aches. Vomiting is also quite common. After about 15 days, the virus will begin attacking skin cells, causing pimples to appear, at first in the mouth, then in the arms and hands. This is when the disease is most contagious.

There are two separate ways for the disease to develop from this point.

• In ordinary smallpox, the spots grow further, forming papules that fill with pus. In the discrete form the ordinary smallpox, the papules remain separate and the chances of survival are quite high. The confluent form of the ordinary smallpox is usually fatal, but occurs very rarely. It is characterized by the unification of the papules, causing skin to detach from the underlying flesh. If the infected person manages to survive this stage, the papules deflate and dry in time. After they have completely dried, the patient can be considered cured.

• Hemorrhagic smallpox is a very deadly form (mortality rates as high as 96%), with completely different symptoms. The skin remains smooth, but strong bleeding occurs in the organs and under the skin, causing the whites of the eye to turn red and the skin to become black. This can cause death by hypovolemic death or severe dehydration, but associated infections can also cause death, since the immune system is weakened, and the skin and intestine are no longer a barrier.

Prevention and treatment

Vaccines against smallpox exist and are highly effective. During the disease, treatment is mostly supportive, involving administration of fluids. Irritation of the papules should be avoided, in order to prevent skin marks from developing after smallpox has been cured.