Text A. The Scientific Basis of Medicine

The word “disease” explains its meaning: uneasiness and distress because

some part of the body is not working properly. Disease is a departure from a state

of health. The distinction between disease and health may be hard to draw, except

at the extremes of disease. There are degrees of health and degrees of disease; there is no such condition as perfect health. A disease is a condition that impairs the proper function of the body or of one of its parts. All living things can succumb to disease. People, for example, are often infected by bacteria, but bacteria, in turn, can be infected by certain viruses. Specific diseases are usually

recognized by the sequence of signs and symptoms they present.

We have fought against disease from the beginning of history but only

during the past 200 years we have done so in a scientific manner. During the Middle Ages people regarded the terrible outbreaks of bubonic plague, known as the Black Death, as something that could not be avoided. For hundreds of years they remained largely ignorant of the causes of disease.
Towards the end of the 18^th century, however, an English doctor, Edward Jenner, discovered that smallpox, another infectious and dangerous disease, could be prevented by the process known as vaccination. In 1885, the French scientist, Louis Pasteur, developed a similar treatment for hydrophobia, or rabies, which causes a form of madness. Pasteur discovered that many diseases are caused by microscopic organisms, or germs. These are mostly one-celled bacteria, viruses, and protozoa. Most fatal diseases are of the bacteria type. The exact bacterium that causes the disease has been discovered in the case of many Illnesses, such as tuberculosis, diphtheria, pneumonia, scarlet fever, typhoid fever, and tetanus, or lockjaw. Malaria is caused by a protozoon carried by mosquitoes.
Viruses are responsible for yellow fever, smallpox, rabies, measles, influenza, poliomyelitis and the common cold. Viruses are the smallest and most resistant of these organisms. Most of the time they appear lifeless. They are recognizable as being alive by the fact that they grow and multiply under certain conditions.

Gradually doctors and other scientists came to realize that each disease has a

cause. When the cause is found, it becomes easier to prevent or cure the disease. Medicine began to take on a scientific basis as researchers looked at where

ill-health occurred, and at who became ill, and when. This branch of medical

research is called epidemiology. They asked questions such as:
• is an illness more common among people who do a particular job?
• is it more common among those who eat a certain kind of food?
• do those people who are affected live in a certain kind of place?

• do sufferers from a disease have other family members who suffer?
Answers to these questions, and to many similar ones, give doctors an

idea as to how a particular disease might be caused. By following up this work in hospitals, doctors surgeries, and laboratories all over the world, we have come to understand the causes of many diseases. Diagnosis of illness from what is wrong with the person (the symptoms), forms an important part of deciding which disease is which.

Hundreds of different diseases exist in nature, and every disease has a cause, though the causes of some remain to be discovered. Each disease has a particular set of symptoms and signs – clues that assist in diagnosis. A symptom is something a patient can detect, such as nausea, bleeding, or pain. A sign is something that a doctor can observe in a patient. Furthermore, a sign can be quantified, or measured, while a symptom cannot. For example, chest pain is a symptom – its presence does not indicate its cause, and the pain itself cannot be measured. An abnormal heart rate, however, is a sign – it can be measured and otherwise evaluated by the physician. The results of this evaluation help determine the cause of the abnormal heart rate, which could be due to many different factors.

All diseases display a cycle consisting of the onset, or beginning of

symptoms; the course, or time span of affliction; and the resolution, or end of the

disease. This may occur when the disease and its signs and symptoms disappears

via a cure or through the death of the patient. Some diseases, such as polio, are

considered “resolved” even though the victim is left disabled.

Notes:

bubonic plague бубонная чума

smallpox оспа

rabies бешенство

measles корь

protozoa простейшие

tetanus столбняк, тетанус

lockjaw тризм челюсти; столбняк

succumb (to) погибнуть, умереть (от болезни)