CBSE - Why Do We Fall ill

The two conditions essential for good health are:

(i) An individual must have better health facilities and more professionals to deal with health problems.

(ii) All basic necessary conditions to prevent diseases must be present. For example, proper garbage collection and disposal, clearing of drains, supply of healthy drinking water, etc

Two conditions essential for being disease-free are: 
→ Person should take balance diet. 
→ Personal and community hygiene. 

To some extent they are the same, because if the conditions that are essential for good health are maintained, then automatically the chances of getting a disease will be minimized. But at the same time, we can say that they are different because being health or good health means physical, mental and social well-being while being disease-free means not suffering from a particular disease.

Common symptoms which indicate sickness are:
→ Headache
→ Cough
→ Dysentery 

If only one of these symptoms is present, we usually do not visit a doctor. This is because such symptoms do not have much effect on our general health and ability to work. However, if a person is experiencing these symptoms for quite sometime, then he needs to visit a doctor for proper treatment.

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.

Answer

Jaundice is a disease that can cause long-term effects on our health. It is a chronic disease that lasts for a long period of time. Jaundice does not spread rapidly, but it develops slowly over a period of time.

When we are sick the normal body functions get disturbed. In such situation food that is easily digestible and contains adequate nutrients are required for the speedy recovery. Thus bland and nourishing food is given during sickness.

The different modes of transmission of infectious diseases are:
→ Through Air: Certain disease-causing micro-organisms are expelled in air by coughing, sneezing, talking, etc. These micro-organisms can travel through dust particles or water droplets in air to reach other people. For example, tuberculosis, pneumonia, etc. spread through air.
→ Through Water: Sometimes causal micro-organisms get mixed with drinking water and spread water borne diseases. Cholera for example is water borne disease.
→ Through Sexual Contact: Sexual act between two people can lead to the transfer of diseases such as syphilis, gonorrhoea, AIDS, etc.
→ Through Vectors: Certain diseases spread by animals called vectors. For example mosquitoes spread malaria.

Precautions to reduce incidence of infectious diseases are:
→ Staying away from the infected person.
→ Covering mouth or nose while coughing or sneezing to prevent the spread of disease.
→ Drinking safe water.
→ Keeping the school environment clean to prevent multiplication vectors.

Immunizationis defined as protection of the body from communicable diseases by administration of some agent that mimics the microbe.

The immunization programmes available at the nearest health centre are DPT (Diphtheria, Pertusis, and Tetanus), polio vaccine, hepatitis B, MMR (Measles, Mumps, and Rubella), jaundice, typhoid, etc.
Of all these diseases, jaundice and typhoid are major health problems.

How many times did you fall ill in the last one year? What were the illnesses?

(a) Think of one change you could make in your habits in order to avoid any of /most of the above illnesses.

(b) Think of one change you would wish for in your surroundings in order to avoid any of/most of the above illnesses.

Answer :

This varies from person to person. Some people fall ill several times in a year, while others do not fall ill at all. A person's immune system and hygiene-related habits play a major role in determining the person's health.

The following precautions must be taken by a doctor/ nurse/ health-worker:
→ Wearing a mask when in contact with a diseased person.
→ Keeping yourself covered while moving around an infected place.
→ Drinking safe water.
→ Eating healthy and nutritious food.
→ Ensuring proper cleanliness and personal hygiene.

Three most common diseases are:

(i) Tuberculosis

(ii) Typhoid

(iii) Jaundice

Steps to be taken to bring down the incidence of these diseases are:

(i) Proper disposal of sewage.

(ii) Ensuring supply of safe drinking water.

(iii) Providing a clean environment and preventing mosquitoes from breeding.

(a) The baby is sick can be determined by his/her behavioural changes such as constant crying of baby, improper intake of food, frequent mood changes, etc.

(b) The sickness is determined by symptoms or indications that can be seen in the baby. The symptoms include vomiting, fever, loose motion, paleness in the body, etc.

Under which of the following conditions is a person most likely to fall sick?
(a) when she is recovering from malaria.
(b) when she has recovered from malaria and is taking care of someone suffering from chicken-pox.
(c) when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.

Answer

(c)A person is more likely to fall sick when she is on a four day fast after recovering from malaria and is taking care of someone who is suffering from chicken pox. This is because she is fasting during recovery, and her immune system is so weak that it is not able to protect its own body from any foreign infection. If she is taking care of someone suffering from chicken pox, then she has more chances of getting infected from chicken pox virus and will get sick again with this disease.

Under which of the following conditions are you most likely to fall sick?
(a) when you are taking examinations.
(b) when you have travelled by bus and train for two days.
(c) when your friend is suffering from measles.

Why?

Answer

(c) You are more likely to fall sick when your friend is suffering from measles. This is because measles is highly contagious and can easily spread through respiration i.e., through air. Thus, if your friend is suffering from measles, stay away from him otherwise you might easily get infected with the disease.

1. Which one of the following is not a viral disease?
(a) Dengue
(b) AIDS
(c) Typhoid
(d) Influenza
Ans. (c) Typhoid
Explanation: Typhoid is a bacterial disease.

2. Which one of the following is not a bacterial disease?
(a) Cholera
(b) Tuberculosis
(c) Anthrax
(d) Influenza
Ans. (d) Influenza
Explanation: Influenza is a viral disease.

3. Which one of the following disease is not transmitted by mosquito?
(a) Brain fever
(b) Malaria
(c) Typhoid
(d) Dengue
Ans. (c) Typhoid
Explanation: Typhoid does not need a vector for transmission. It is transmitted through contaminated food and water.

4. Which one of the following disease is not caused by bacteria?
(a) Typhoid
(b) Anthrax
(c) Tuberculosis
(d) Malaria
Ans. (d) Malaria
Explanation: Malaria is cause by protozoa.

5. Which one of the following diseases is caused by protozoans?
(a) Malaria
(b) Influenza
(c) AIDS
(d) Cholera
Ans. (a) Malaria

6. Which one of the following has a long-term effect on the health of an individual? 
(a) Common cold
(b) Chicken pox
(c) Chewing tobacco
(d) Stress
Ans. (c) Chewing tobacco
Explanation: Common cold and chicken pox are acute diseases and hence do not have long term effects. Stress can be managed by making certain changes in lifestyle. But the effect of chewing tobacco remains for a long time even after giving it up.

7. Which of the following can make you ill if you come in contact with an infected person?
(a) High blood pressure
(b) Genetic abnormalities
(c) Sneezing
(d) Blood cancer
Ans. (c) Sneezing
Explanation: Diseases in other options are non-infectious diseases. Sneezing is one of the symptoms of common cold and many other respiratory diseases. All these diseases are infectious diseases. Hence, sneezing can spread infectious disease from one person to another.

8. AIDS cannot be transmitted by
(a) sexual contact
(b) hugs
(c) breast feeding
(d) blood transfusion
Ans. (b) hugs
Explanation: Exchange of body fluids is necessary for transmission of AIDS. Exchange of body fluids is not possible through hugs. Hence, AIDS does not get transmitted by hugging.

9. Making anti-viral drugs is more difficult than making anti-bacterial medicines because
(a) viruses make use of host machinery
(b) viruses are on the border line of living and non-living
(c) viruses have very few biochemical mechanisms of their own
(d) viruses have a protein coat
Ans. (c) viruses have very few biochemical mechanisms of their own

Explanation: All anti-bacterial medicines stop some or the other metabolism in bacteria and thus are effective in controlling further spread of bacteria. Since viruses have very few biochemical mechanisms of their own, it is highly difficult to make medicines to act against a particular metabolism. Hence, making anti-viral drugs is more difficult than making anti-bacterial medicines.

10. Which one of the following causes kala-azar? 
(a) Ascaris
(b) Trypanosoma
(c) Leishmania
(d) Bacteria
Ans. (c) Leishmania
Explanation: Leishmania is a protozoan which causes kala-azar.

11. If you live in an overcrowded and poorly ventilated house, it is possible that you may suffer from which of the following diseases
(a) Cancer
(b) AIDS
(c) Air borne diseases
(d) Cholera
Ans. (c) Air borne diseases
Explanation: Living in enclosed spaces increases the risk of air-borne diseases.

12. Which disease is not transmitted by mosquitoes?
(a) Dengue
(b) Malaria
(c) Brain fever or encephalitis
(d) Pneumonia
Ans. (d) Pneumonia
Explanation: Pneumonia is transmitted through air.

13. Which one of the following is not important for individual health?
(a) Living in clean space
(b) Good economic condition
(c) Social equality and harmony
(d) Living in a large and well-furnished house
Ans. (d) Living in a large and well-furnished house
Explanation: If a large and well-furnished house is not clean; then it is not enough to ensure health. Conditions shown in other options are more important for being healthy.

14. Choose the wrong statement
(a) High blood pressure is caused by excessive weight and lack of exercise.
(b) Cancers can be caused by genetic abnormalities
(c) Peptic ulcers are caused by eating acidic food
(d) Acne in not caused by staphylococci
Ans. (c) Peptic ulcers are caused by eating acidic food
Explanation: Peptic ulcers are caused by a bacterium known as Helicobacter pylori.

15. We should not allow mosquitoes to breed in our surroundings because they
(a) multiply very fast and cause pollution
(b) are vectors for many diseases
(c) bite and cause skin diseases 
(d) are not important insects
Ans. (b) are vectors for many diseases
Explanation: Diseases spread by mosquitoes are very dangerous; like malaria and dengue. Hence, it is important to prevent the breeding of mosquitoes.

16. You are aware of Polio Eradication Programme in your city. Children are vaccinated because
(a) vaccination kills the polio causing microorganisms
(b) prevents the entry of polio causing organism
(c) it creates immunity in the body
(d) all the above
Ans. (c) it creates immunity in the body
Explanation: Any vaccine helps in creating immunity in the body against a particular disease for which the vaccine is being made.

17. Viruses, which cause hepatitis, are transmitted through
(a) air
(b) water
(c) food
(d) personal contact
Ans. (b) water
Explanation: Hepatitis is a viral disease and spreads through contaminated water. But hepatitis B is spread through exchange of body fluids.

18. Vectors can be defined as
(a) animals carry the infecting agents from sick person to another healthy person
(b) microorganisms which cause many diseases
(c) infected person
(d) diseased plants
Ans. (a) animals carry the infecting agents from sick person to another healthy person Explanation: Vectors are in fact live carries of germs of diseases.

Give two examples for each of the following
(a) Acute diseases
(b) Chronic diseases
(c) Infectious diseases
(d) Non-infectious diseases
Ans. (a) Viral fever, Flu
(b) Elephantiasis, Tuberculosis (TB)
(c) Small pox, Chicken pox
(d) Diabetes, Goitre

(i) Sleeping sickness caused by Trypanosoma/ Malaria by plasmodium
(ii) Kala-azar caused by Leishmania

(i) Helicobactor pylori
(ii) Marshall and Warren.

Antibiotic is a chemical substance that kill bacteria, secreted by microorganisms which can kill the pathogens. Examples, Penicillin and Streptomycin.

(a) Pneumonia is an example of __________ disease.
Ans. Communicable
(b) Many skin diseases are caused by __________.
Ans. Fungi
(c) Antibiotics commonly block biochemical pathways important for the growth of
__________.
Ans. Bacteria
(d) Living organisms carrying the infecting agents from one person to another are called
__________.
Ans. Vector

(a) Hepatitis targets __________.
Ans. Liver
(b) Fits or unconsciousness targets __________.
Ans. Brain
(c) Pneumonia targets __________.
Ans. Lungs
(d) Fungal disease targets __________.
Ans. Skin

Edward Jenner was the first to discover vaccine. Vaccines can be used to prevent small pox and polio.

(a) __________ disease continues for many days and causes __________ on body.
Ans. Chronic, long term effect
(b) __________ disease continues for a few days and causes no longer term effect on body.
Ans. Acute
(c) __________ is defined as physical, mental and social well-being and comfort.
Ans. Health
(d) Common cold is __________ disease.
Ans. Infectious/ communicable
(e) Many skin diseases are caused by __________.
Ans. Fungi

(a) AIDS
Ans. infectious
(b) Tuberculosis
Ans. infectious
(c) Cholera
Ans. infectious
(d) High blood pressure
Ans. non-infectious
(e) Heart disease
Ans. non-infectious
(f) Pneumonia
Ans. infectious
(g) Cancer
Ans. non-infectious

Bacteria and fungi

Malaria, dengue and chikungunya 

(a) Balanced diet is necessary for maintaining healthy body.
Ans. Food is necessary for the growth and development of the body. Balanced diet provides raw materials and energy in appropriate amount needed for the substances likes protein, carbohydrates, fats, minerals etc which in turn are essential for the proper growth and functioning of the healthy body.

(b) Health of an organism depends upon the surrounding environmental conditions.
Ans. Health is a state of being well enough to function well physically, mentally and socially and these conditions depend upon the surrounding environmental conditions. 
eg., If there are unhygienic conditions in surrounding area, it is likely we might get infected or diseased.

(c) Our surrounding area should be free of stagnant water.
Ans. This is so because many water borne diseases and insect vectors flourish in stagnant water which cause diseases in human beings.

(d) Social harmony and good economic conditions are necessary for good health.
Ans. Human beings live in societies and different localities like villages or cities, which determines the social and physical environment and hence both are to be kept in harmony. Public cleanliness is important for individual health. For better living conditions lot of money is required. We need good food for healthy body and for this we have to earn more. For the treatment of diseases also, one has to be in good economic condition. 

A condition in which the functioning of the body or a part of it changes adversely, it is called disease.
Types of diseases:

• Acute Diseases: Diseases which last for only very short period of time. 
Example,  cough, cold, fever, etc.
• Chronic Diseases: Diseases which last for a long time and adversely affect the health of a person. 
Example, AIDS, encephalitis, etc.
• Infectious Diseases: Diseases which spread from an infected person to a healthy person. 
Example, malaria, typhoid, cholera, tuberculosis, etc.
• Non-infectious Diseases: Diseases which do not spread from an infected person to a healthy person. 
Example, Diabetes, arthritis, hypertension, heart disease, cancer etc.
Non-infectious diseases can be further divided into two categories:
(a) Lifestyle Diseases: Diabetes, hypertension, etc.
(b) Genetic Diseases: Haemophilia, sickle-cell anemia, etc.

When the functioning or the appearance of one or more systems of the body will change for the worse, it gives certain abnormal signs of the disease. These visual changes in human beings are called symptoms. Symptoms give indication of the presence of a particular disease.
Example (i) Lesions on the skin are the symptoms of chickenpox.
Example (ii) Cough is the symptom of lung infection.

The immune system of our body is a kind of defense mechanism to fight against pathogenic microbes. It has cells that are specialized to kill infecting microbes and keep our body healthy.

Following precautions should be taken for prevention of disease.
(1) Maintaining hygienic conditions.
(2) Awareness about the disease and causal organism.
(3) Balanced diet.
(4) Regular medical check-up.

Some children have weak immune system which can happen because of various reasons. 
A child may not be getting balanced diet. A child may be living in congested and unhygienic locality. A child may not be getting clean drinking water. These children are at more risk of falling ill than others living in the same locality.

Antibiotics generally block the biosynthetic pathways and they block these pathways of the microbes/bacteria. However, viruses have very few biochemical mechanisms of their own and hence are unaffected by antibiotics.

Because of strong immune system our body is normally fighting off microbes. We have cells which are specialised to kill the pathogenic microbes. These cells are active when infecting microbes enter the body and if they are successful in removing the pathogen, we remain disease– free. So even if we are exposed to infectious microbes, it is not necessary that we suffer from diseases.

For a healthy person, it is necessary that
(i) The surrounding environment should be clean. Air and water borne diseases will not spread.
(ii) Personal hygiene prevents infectious diseases. 
(iii) Proper, sufficient nourishment and food is necessary for good immune system of our body.
(iv) Immunisation against severe diseases.

AIDS causing virus— HIV that comes into the body via, the sexual organs or any other means like blood transfusion will spread to lymph nodes all over the body. The virus damages the immune system of the body and due to this the body can no longer fight off many minor infections. Instead, every small cold can become pneumonia, or minor gut infection can become severe diarrhoea with blood loss. The effect of disease becomes very severe and complex, at times killing the person suffering from AIDS. Hence there is no specific disease symptoms for AIDS but it results in a complex diseases and symptoms.
Therefore, it is known as a syndrome.