WHAT DOES DISEASE LOOK LIKE?
Let us now think a little more about diseases. In the first place, how do we know that there is a disease? In other words, how do we know that there is something wrong with the body? There are many tissues in the body, as we have seen in Chapter 6. These tissues make up physiological systems or organ systems that carry out body functions. Each of the organ systems has specific organs as its parts, and it has particular functions. So, the digestive system has the stomach and intestines, and it helps to digest food taken in from outside the body. The musculoskeletal system, which is made up of bones and muscles, holds the body parts together and helps the body move.
When there is a disease, either the functioning of one or more systems of the body will change for the worse. These changes give rise to symptoms and signs of disease. Symptoms of the disease are the things we feel as being ‘wrong’. So we have a headache, we have cough, we have loose motions, we have a wound with pus; these are all symptoms. These indicate that there may be a disease, but they don’t indicate what the disease is. For example, a headache may mean just examination stress or, very rarely, it may mean meningitis, or anyone of a dozen different diseases.
Signs of disease are what physicians will look for on the basis of the symptoms. Signs will give a little more definite indication of the presence of a particular disease. Physicians will also get laboratory tests done to pinpoint the disease further.
Source: This topic is taken from NCERT TEXTBOOK
ACUTE AND CHRONIC DISEASES
The manifestations of the disease will be different depending on a number of factors. Some diseases last for only very short periods of time, and these are called acute diseases. We all know from experience that the common cold lasts only a few days. Other ailments can last for a long time, even as much as a lifetime, and are called chronic diseases. An example is an infection causing elephantiasis, which is very common in some parts of India.
Activity 13.4:
* Survey your neighbourhood to find out:
1. how many people suffered from acute diseases during the last three months,
2. how many people developed chronic diseases during this same period,
3. and finally, the total number of people suffering from chronic diseases in your neighbourhood.
* Are the answers to questions (1) and different?
* Are the answers to questions (2) and different?
* What do you think could be the reason for these differences? What do you think would be the effect of these differences on the general health of the population?
Source: This topic is taken from NCERT TEXTBOOK
CHRONIC DISEASES AND POOR HEALTH
Acute and chronic diseases have different effects on our health. Any disease that causes poor functioning of some part of the body will affect our health. This is because all functions of the body are necessary for being healthy.
But an acute disease, which is over very soon, will not have time to cause major effects on general health, while a chronic disease will do so.
As an example, think about a cough and cold, which all of us have from time to time. Most of us get better and become well within a week or so. And there are no lasting effects on our health. But if we get infected with a chronic disease such as tuberculosis of the lungs, then being ill over the years does make us lose weight and feel tired all the time.
We may not go to school for a few days if we have an acute disease. But a chronic disease will make it difficult for us to follow what is being taught in school and reduce our ability to learn. In other words, we are likely to have prolonged general poor health if we have a chronic disease. Chronic diseases, therefore, have very drastic long-term effects on people’s health as compared to acute diseases.
Source: This topic is taken from NCERT TEXTBOOK
CAUSES OF DISEASES
What causes disease? When we think about the causes of diseases, we must remember that there are many levels of such causes. Let us look at an example. If there is a baby suffering from loose motions, we can say that the cause of the loose motions is probably an infection.
But the next question is – where did the infection come from? Suppose we find that the infection came through unclean drinking water. But many babies must have had this unclean drinking water. So, why is it that one baby developed loose motions when the other babies did not?
One reason might be that this baby is not healthy. As a result, it might be more likely to have the disease when exposed to risk, whereas healthier babies would not. Why is the baby not healthy? Perhaps because it is not well nourished and does not get enough food. So, the lack of good nourishment becomes a second cause of the disease. Further, why is the baby not well nourished? Perhaps because it is from a household which is poor.
It is also possible that the baby has some genetic difference that makes it more likely to suffer from loose motions when exposed to a pathogen. Without the pathogen, the genetic difference or the poor nourishment alone would not lead to loose motions. But they do become contributory causes of the disease.
Why was there no clean drinking water for the baby? Perhaps because the public services are poor where the baby’s family lives. So, poverty or lack of public services becomes the third cause of the baby’s disease.
It will now be obvious that all diseases will have immediate causes and contributory causes. Also, most diseases will have many causes, rather than one single cause.
Questions
1. List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not?
2. In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?
* if you get jaundice,
* if you get lice,
* if you get acne. Why?
Source: This topic is taken from NCERT TEXTBOOK
INFECTIOUS AND NON INFECTIOUS CAUSES
As we have seen, it is important to keep public health and community health factors in mind when we think about the causes of diseases. We can take that approach a little further. It is useful to think of the immediate causes of disease as belonging to two distinct types. One group of causes is infectious agents, mostly microbes or micro-organisms. Diseases, where microbes are the immediate causes, are called infectious diseases. This is because the microbes can spread in the community, and the diseases they cause will spread with them.
On the other hand, there are also diseases that are not caused by infectious agents. Their causes vary, but they are not external causes like microbes that can spread in the community. Instead, these are mostly internal, non-infectious causes.
For example, some cancers are caused by genetic abnormalities. High blood pressure can be caused by excessive weight and lack of exercise. You can think of many other diseases where the immediate causes will not be infectious.
The ways in which diseases spread and the ways in which they can be treated and prevented at the community level would be different for different diseases. This would depend a lot on whether the immediate causes are infectious or non-infectious.
Peptic ulcers and the Nobel prize
For many years, everybody used to think that peptic ulcers, which cause acidity– related pain and bleeding in the stomach and duodenum, were because of lifestyle reasons. Everybody thought that a stressful life led to a lot of acid secretion in the stomach and eventually caused peptic ulcers.
Then two Australians made a discovery that a bacterium, Helicobacter pylori, was responsible for peptic ulcers. Robin Warren (born 1937), a pathologist from Perth, Australia, saw these small curved bacteria in the lower part of the stomach in many patients. He noticed that signs of inflammation were always present around these bacteria. Barry Marshall (born 1951), a young clinical fellow, became interested in Warren’s findings and succeeded in cultivating the bacteria from these sources.
In treatment studies, Marshall and Warren showed that patients could be cured of peptic ulcers only when the bacteria were killed off from the stomach. Thanks to this pioneering discovery by Marshall and Warren, peptic ulcer disease is no longer a chronic, frequently disabling condition, but a disease that can be cured by a short
period of treatment with antibiotics.
For this achievement, Marshall and Warren (seen in the picture) received the Nobel prize for physiology and medicine in 2005.
Questions
1. Do all diseases spread to people coming in contact with a sick person?
2. What are the diseases that are not spreading?
3. How would a person develop those diseases that don’t spread by contact with a sick person?
Source: This topic is taken from NCERT TEXTBOOK