9th Class Science Why do we fall Ill? Why Do We Fall Ill

Why Do We Fall Ill

Category : 9th Class

Why do we fall Ill


Health is the real wealth. But health and disease are among the most complicated issues in our life. We have to deal with this issue in our life more often. The most important thing to know is that why we fall ill? It has been rightly said prevention is better than cure. The various organ systems in our body work smoothly to keep us healthy.


Health and Its Failure

Health is an idea of being well. A good health allows us to work well physically, mentally and socially. A good health enables us to cope up with the social, mental and physical pressure without any difficulty. To keep ourselves fit and healthy we must take a balanced diet, regular exercise and cleanliness in and around us. If we do not follow the above mentioned points then we may fall ill. A disease can also be caused because of the malfunctioning of some nutrients or failure of our organs.


Individual and Community Health

As we have mentioned earlier that health means a state of physical, mental and social well-being, but it cannot be achieved at an individual level. The health of all the organisms depends on the environment and their surroundings. We live in a society because our social environment is an important part of our individual health. In the community, physical environment is directly related to social environment. There are various agencies in our communities that are responsible for providing cleanliness. If they will not work properly then we cannot expect healthy life. For example, in a city if garbage is not dumped properly or drains are not cleaned then our community can become a breeding place for disease causing bacteria and germs. In a community, the availability of lean drinking water, adequate nutritious food, social equality and harmony needs to be provided to keep all the people healthy.


Disease and Its Causes

There are various organ systems in our body that work collectively to keep us healthy. A disease can occur when the normal state of a man is disturbed or a particular organ or organ system starts malfunctioning. The cause of disease arise from person to person and from place to place.


The following table provides a list of disease in human and its causes:


Type of disease

Causes of disease



Temporary or permanent damage to body parts.

Bone fracture


Invasion of the body by other organisms such as viruses, bacteria, fungi, protozoan, nematodes

Typhoid, malaria, hepatitis, rabies,

AIDS, T.B., polio, influenza,




Inadequate diet

Kwashiorkor, marasmus, scurvy, rickets, anaemia, goiter, xerophthalmia, ber-beri


Defective genes passed on from parents to offspring

Haemophilia, sickle-cell anaemia, cystic fibrosis


Brain damage or psychological

Depression, paranoia


Social interactions with family friends and strangers

Drug dependence, alcoholism, smoking, unhealthy lifestyles, social isolation


Deficient nutrient




Protein and carbohydrates


Vitamin A


Vitamin A

Night blindness




Pernicious anaemia


Microcytic anaemia

Vitamin C


Vitamin D

Rickets (in children)



Deficient nutrient


Vitamin K

Bleeding disease


Dental caries




Types of Diseases

Acute Diseases: These are the diseases that last for a short period and do not cause major harm to our body. They can be cured easily with simple medicines and sometimes even without medicine. For example, cough and cold. They are very common. We all suffer from cough and cold and get better within a week or so. The impact of these diseases is minor. We neither loose our body weight nor we-need to go for complete rest.


Chronic Diseases: These are the diseases that last for long duration. They cannot be cured easily and causes enough harm to our body. A person suffering from chronic disease loses weight, feels tired and needs complete rest. It makes us bed ridden. For example, TB, lung disease, etc. We suffer from these diseases for a long time that is over the years. These diseases have prolonged effect in our life.


Infectious and Non-Infectious Causes: There are many factors that are responsible than causing infectious and non-infectious diseases. As you know that prevention is better than cure, so you need to prevent the diseases by knowing the causes of these diseases. As we have seen, it is important to keep public health and community health factors in mind when we think about causes of diseases. It is practical to think of the direct causes of disease. Microbes and microorganisms are the cause of infectious diseases. They are also called infectious agents. Microbes are found in the entire community and spread the diseases in the whole area.


Infection Agent

The following are the infection agents:

Image result for Micro-organisms Bacteria, Viruses, Algae, fungi



Some Common Diseases Caused by Pathogens



Type of Pathogen

Diseases Caused in Living Organisms


Common cold, poliomyelitis, SARS, AIDS, dengue fever, smallpox, chickenpox, measles


Typhoid, cholera, tuberculosis, tetanus, syphilis, diphtheria, pneumonia


Skin infections, ringworm, athlete?s foot


Malaria, amoebiasis (amoebic dysentery), kala-azar, trypanosomiasis


Taeniasis (tapeworm infection), elephantiasis (pin worm infection), ascariasis (round worm infection)


Means of Spreading Infectious Diseases

Infectious diseases spread from a sick person to a healthy person in the following ways:

Through air: Air is a medium through which infectious agents spread the disease. When a person suffering from infectious diseases sneezes or coughs, the disease causing microbes enter into the air and then enter into the body of a healthy person standing nearby. Thus, a healthy person comes under the influence of that disease. The diseases that spread through air are: Common cold, pneumonia, tuberculosis, etc.


Related image

When close to infected person air transmitted diseases are easier to catch


Through water: Water is another medium that helps in spreading diseases from a sick person to healthy person. When the stool of a person suffering from an infectious gut disease mixes with drinking water; it causes disease such as cholera. The water of dirty drains mixes with drinking water also causes diseases.


Sexually transmitted disease: Few diseases that are transmitted sexually, such as syphilis and AIDS, are fatal and at certain stage incurable. These diseases are not caused by casual physical contact. It can spread only when an unhealthy person develops sexual relation with a healthy person.

Structure of HIV


Through animal: Animals are the major sources of spreading infectious disease. Animals that live around us carries disease causing germs from sick person to a healthy person and thus causes diseases. For example, mosquitoes.

Image result for Common methods of transmission of diseases

          Common methods of transmission of diseases


Treatment of Infectious Diseases

Infectious diseases can be treated in two different ways. The first way is to reduce the Tweets of the disease and the other is to uproot the disease from the body. For reducing the effect, treatment is provided that reduces the effects and symptoms. For example, we can take medicines that bring down fever, reduce pain and loose motions. We can take bed rest so that we can conserve our energy. These all above mentioned procedures reduces the effect and helps in healing of the disease. The major drawback of this kind of treatment is that it suppresses the disease for the time being not on permanent basis. To cure the disease permanently, we have to kill the disease causing microbes. These microbes can be killed by medicines that are available for the same purpose.

Microbes are classified into viruses, bacteria, fungi and protozoa. These all microbes have peculiar essential biochemical life process that is not similar to others. We need to use the special medicine that kills the bacteria without affecting our body. Many antibiotics have been developed on the basis of this process only.


Prevention of Infectious Diseases

Prevention is the best way to stop the growth of disease in and around us. There are many ways to prevent diseases. Here we will discuss about the two ways that help in the prevention of infectious diseases. One way is general and the other is specific. The general way is that you should keep your surroundings neat and clean. Community cleanliness programme should be strictly implemented. We should not allow the breeding of germs and microbes in our surrounding by keeping them neat and clean. We should drink clean water. We must maintain public health and hygiene properly. The specific way is directly related to our immune system. We need to develop a strong immune system in our body so that it can fight with the diseases and do not allow these diseases to cause harm to our body. The person having a strong immune system does not get affected by the infectious diseases easily. To develop a strong immune system, we must take a proper and balanced diet that contains all the nutrients in right amount required by our body

Regular exercise is also helpful in this regard.

Notes - Why Do We Fall Ill
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