Class IX – Why do we fall ill?

Ans. Bacteria and fungi

Ans. It is advised so because the scarcity (loss) of nutrients caused during sickness gets fulfilled.

Ans. Vaccination helps to induce the production of specific antibodies to confer immunity against subsequent infection.

Ans. (i) Vaccine against measles

(ii) B.C.G vaccine against T.B

Ans. This is because from the beginning they are exposed to the virus through water.

Ans. (i) AIDS (ii) Syphilis

Ans. (i) Sleeping sickness caused by Trypanosoma, Malaria by Plasmodium

(ii) Kala-azar caused by Leishmania

Ans. (i) Helicobacter pylori

(ii) Marshall and Warren

Ans. Antibiotics are a chemical substance that kills bacteria, secreted by microorganisms which can kill the pathogens. Examples: Penicillin and Streptomycin.

Ans. Malaria, Dengue, Kala-azar and Plague

Ans. (i) Balanced diet

(ii) Disease free environment

(iii) Proper sanitation

(iv) Mental and social stability

Ans. Chronic disease lasts for a longer time thus it is more harmful in comparison to acute disease. For example, cough and cold, viral fever are acute diseases which do not affect our health badly and we become well within a week or so while tuberculosis (TB) which is a chronic disease affects health drastically and has a long time effect on our body.

Ans. Signs and symptoms indicate the presence of a particular disease. Because when there is a disease, either the functioning or the appearance of one or more systems of the body will be adversely affected.

Ans. (i) Blood to blood contact (transfusion).

(ii) Sexual intercourse

(iii) Pregnant mother to her child

(iv) Use of infected needles.

Ans. An epidemic is the rapid and extensive spread of disease that affects many individuals simultaneously in a particular area. It is generally an infectious disease

Ans. Liver is affected in case of jaundice.

Ans. Water borne infections can be prevented by providing safe drinking water. Vector borne infections can be prevented by providing clean environment.

Ans. Acne – Staphylococci

Sleeping sickness – Trypanosoma

Ans. Japanese encephalitis is caused by a virus which enters into the human body through mosquito bite. By keeping the surrounding clean and taking proper measures against mosquito bite, it can be prevented.

Ans. Health is a state of being well enough to function well physically, mentally and socially. The health of any individual depends upon better social environment, better public cleanliness, good economic conditions, social equality and harmony.

Ans. The conditions essential for being free of disease are: Eating good food (balanced diet). Maintaining personal and public hygiene and clean surroundings.

Ans. When a person is sick, then his normal body functions get disturbed. In such a situation, such food is required which is easy to digest and contains adequate nutrients for the speedy recovery. Thus, bland and nourishing food is required during sickness.

Ans. I am most likely to fall sick when I am near to my friend who is suffering from measles. Since measles is an acute infectious disease caused by a virus. This disease is characterised by fever and a blotchy rash. This means that one should stay away from a person suffering from measles.

Ans. Every microorganisms shows its effect on any particular tissue or organ after entering into the body. Thus, there is a change in the structure and function of that tissue or organ. For example, if the lungs are the targets, the symptoms will be cough and breathlessness. If the liver is the target, there will be jaundice. This is called organ specific manifestation.

Ans. AIDS is caused by HIV which damages the immune system of the person suffering from it. Thus, the person cannot fight even small infections.

(a) Stagnant water in the surroundings

(b) Accumulation of garbage

Because Female Anopheles mosquitoes require large amount of proteins to lay their eggs.

Ans. In the human body, when there is an infection, an active immune system recruits many cells to the affected tissue to kill the disease-causing microbes as an immune response. This recruitment process is called inflammation.

Symptoms: (i) Swelling and pain

(ii) Fever

Ans. We can prevent disease in two ways:

(a) General ways: By preventing exposure to infectious microbes. By providing safe drinking water and public hygiene. By providing a proper and balanced diet.

(b) Specific ways: By immunization

The process of developing immune power in the body to fight against the diseases is called immunization. In the process of immunization, a vaccine is introduced into the body to which the immune power of the body improves.

Ans. There are two ways to treat an infectious disease:

(i) By reducing the effect of the disease

(a) By symptomatic treatment

(b) By taking a bed rest

(ii) By killing the microorganisms that act as infectious agents.

Ans. AIDS causing virus called Human Immunodeficiency Virus enters the body via the sexual organs or any other means like blood transfusion and later spreads 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. The immune system is so weakened that even a small cold can become pneumonia or a minor gut infection can become severe diarrhea with blood loss. The effect of disease becomes very severe and complex, at times killing the person suffering from AIDS. Hence, there are no specific disease and symptoms. Therefore, it is known as a syndrome.

Ans. Having lice and acne will not have long lasting effects on our body. But if you get jaundice, it will have drastic long-term effects. You will show symptoms such as : High temperature, headache and joint pains. Loss of appetite with a feeling of nausea and vomiting. Irritating rashes. You will have prolonged general poor health which requires complete bed rest for earlier recovery.

The person is suffering from the disease called AIDS (Acquired immunodeficiency syndrome)

(i) Sexual contact with infected person

(ii) From a pregnant mother to her foetus.

(iii) Blood contact with infected person

(iv) Using needle or syringe of infected person.

Immune system of an individual fight from infection carrying microbes.

Immune system of those who does not suffer with cold and cough successfully fought against the microbes to which they were exposed.

Viruses have very few biochemical mechanisms of their own. They depend on their host to complete all the biochemical reaction. Thus, it is very difficult to find the targets where these drugs get interfered by not making any harm to the host.

Any condition which impairs the health, or interferes with the normal functioning of the body is called disease.

A symptom is a phenomenon that is experienced by the individual affected by the disease.

Causes:

(i) Extrinsic factor: Water, food

(ii) Intrinsic factor: Poor eating habits, poor nourishment.

(iii) Genetic constitution: Weak immune system.

(iv) Social reason: Poor public services.

Types of diseases:

(i) Acute diseases: Last for short period of time. Ex. Common cold.

(ii) Chronic diseases: Lasts for long time even for lifetime. Eg. diabetes

No, it is not a sign of good immune system. Only some children fall ill means they have less resistance to diseases which is due to poor immune system.

No, personal hygiene is important to develop resistance against diseases. If the children are falling ill frequently, it means that they might be neglecting health and hygiene.

Name of the disease: Acquired immune-deficiency syndrome (AIDS)

Causative agent: Human immune-deficiency virus (HIV)

Mode of transmission – Air

Through air – Common cold or cough may occur as these are communicable diseases which spread through air.

Availability of proper and sufficient food is one of the measure to prevent the occurrence of the infectious diseases. As the infectious diseases also spread through the food we eat; thus, if we obtain healthy and nutritious food, free of germs causing diseases, it would definitely prevent us from catching the infection.

Yes, balanced diet provides raw materials and energy in appropriate amount in the form of protein, carbohydrates, fats, minerals, etc., which, in turn, are essential for the proper growth and functioning of the healthy body.

Yes, health is a state of being well enough to function well physically, mentally and socially, and these conditions depend upon the surrounding environmental conditions, e.g., if there is an unhygienic condition in the surrounding area, it is likely we might get infected or diseased.

Yes, this is so because many water-borne disease and insect vectors flourish in stagnant water which causes in human beings.

Acute

diabetes, tuberculosis etc.

Economic stability, public hygiene etc.

doctor diagnoses the disease in a diseased person by observing disease sign and symptoms (elaboration is required)

rabies. rabies is caused by a virus.

Vectors are living organisms that can transmit infectious pathogens between humans, or from animals to humans. Rabies, dengue, chicken guinea etc.

Vaccine is a biological substance designed to protect humans from infections caused by bacteria and viruses. They help the individual to build his immunity against specific diseases. These vaccines will help the body to produce the antibody which fight against the diseases causing pathogen and save the life of the individual.

As the disease affects the body, the functioning of body organs can be a concern, and medication needs which can cause side effects including allergies. There are certain diseases that cannot be treated so the prevention is better than cure.

Ans (b)

(d) The common cold virus can leave the body through the mucus of infected people.

48. Assertion: Poliomyelitis is a highly infectious viral disease of infants and children.

Reason: Pathogen of Poliomyelitis is a very small RNA containing virus

(a) Both A and R are true, and R is correct explanation of the assertion.

(b) Both A and R are true, but R is not the correct explanation of the assertion.

(c) A is true, but R is false.

(d) A is false, but R is true.

Ans. (b)

Poliomyelitis is a highly infectious viral disease of infants and children that may attack adults also. It is caused by small RNA containing virus, polio virus and is transmitted through faeces, urine and nasal secretions contaminating food or drinks either directly or through flies. This virus causes inflammation of grey matter of the spinal cord, inability of head to bend forward and stiffness of the neck. It also destroys motor nerve cells in the spinal cord. Muscles fail to work and shrink due to lack of nerve impulses. This causes paralysis of limbs.

Ans. (c)

The filarial worms cause a slowly developing chronic inflammation of the organs in which they live for many years, usually the lymphatic vessels of the lower limbs, and the disease is called filariasis. The pathogen spreads from one human being to another through mosquitoes like Culex. The parasite resides in lymph vessels, connective tissues and mesentery. In Culex and other mosquitoes, females are blood sucking while males suck juices of flowers and fruits. Female Culex carries filarial worm from one person to another. It prefers to breed in dirty water near human habitation.

Ans (b)

Ans. (c)

Ans. (b)

Ans. (c)

Ans. (d)

Female anopheles’ mosquito

Dengue

The body’s power to resist and overcome an infection/disease

A specific method of preventing diseases by inoculating vaccines inhuman body.

i. By taking care of preventative measures like personal and community hygiene/ cleanliness

ii. Immunization

Acute diseases remain for short duration while chronic diseases remain for a long duration of time.