Disease and Hygiene

Protozoan

Reason — Malaria is caused by protozoan Plasmodium which enters the human body through the bite of a female Anopheles mosquito.
Bacteria cause diseases like typhoid, cholera. Fungi cause ringworm, athlete’s foot. Virus cause diseases like dengue, flu.

Scurvy

Reason — Deficiency of vitamin C causes Scurvy (swollen bleeding gums).
Night blindness is caused by deficiency of Vitamin A. Anaemia is caused by deficiency of iron (in most cases). Polio is caused by a virus (poliovirus).

Allergic diseases

Reason — Hay fever and asthma are allergic diseases because both diseases are caused by unpredictable reaction of the body to a particular substance.
Deficiency diseases occur when the body lacks essential nutrients. Genetic diseases are caused by abnormalities in genes or chromosomes and are often inherited from parents. Organic disease is a term used for diseases that involve structural or physical damage to organs or tissues.

Haemophilia

Reason — Haemophilia is a genetic disease because it is inherited from parent to child.
Scurvy is caused by vitamin C deficiency. Leukemia is a type of blood cancer. Goitre is caused by iodine deficiency.

Cataract

Reason — Cataract is a degenerative disease because it is a age related eye disease which affects older person.
Thalassemia is a genetic blood disorder. Beri-beri is caused by vitamin B₁ deficiency. Diabetes is mainly a metabolic/endocrine disorder.

Vit. B₃

Reason — Pellagra is caused by the deficiency of Vit. B₃ (Niacin).
Vit. B₁ deficiency causes beriberi. Vit. C deficiency causes scurvy. Vitamin D deficiency causes rickets.

Goitre

Reason — Deficiency of Iodine causes Goitre.
Beri-beri is caused by deficiency of Vitamin B1. Scurvy is caused by deficiency of Vitamin C. Pellagra is caused by deficiency of Vitamin B3.

Night blindness

Reason — Night blindness is caused by deficiency of Vitamin A. Sources of Vitamin A are carrot, yellow fruits, vegetables, butter, milk, fish.
Beri-beri is caused by deficiency of Vitamin B1. Dermatitis is commonly linked with deficiency of Vitamin B3 or other B vitamins. Scurvy is caused by deficiency of Vitamin C

Measles

Reason — Measles is a communicable disease because it is spread by direct contact with an infected person.
Cancer is non-communicable disease. Heart stroke is non-communicable condition related to blood circulation. Allergy is immune reaction, not infectious and not communicable.

Viruses

Reason — The contagious disease COVID-19 was spread by viruses.
Bacteria cause diseases like tuberculosis and cholera. Protozoa cause diseases like malaria. Worms cause diseases like filariasis and roundworm infection.

Pneumonia

Reason — Pneumonia is a disease of the lungs caused by a bacteria.
Rabies is caused by a virus. Malaria is caused by a protozoan (Plasmodium). Cholera is caused by bacteria, but it affects the intestines.

Proteins

Reason — Kwashiorkor is a form of malnutrition primarily caused by a lack of protein in the diet.
Carbohydrates deficiency mainly causes energy shortage. Deficiency of proteins, carbohydrates and fats together causes marasmus.

Bleeding gums

Reason — Scurvy is caused by a severe lack of Vitamin C, which is crucial for healthy gums. This deficiency leads to swollen, bleeding gums.
Skin inflammation is common in pellagra/dermatitis. Drying of cornea is due to Vitamin A deficiency. Bones turning soft is due to Vitamin D deficiency (rickets/osteomalacia).

Goitre

Reason — Goitre is caused due to deficiency of Iodine.
Anaemia causes weakness and pale skin. Mumps causes swelling near the cheeks/jaw due to salivary gland infection, not typical thyroid neck swelling. Rabies affects the nervous system.

Typhoid

Reason — Typhoid is a bacterial infection spread through contaminated food and water, not mosquito bites. Its symptoms are continuous fever.
Dengue fever is spread by Aedes mosquitoes. Elephantiasis is spread by female Culex mosquitoes. Malaria is spread by female Anopheles mosquitoes.

A is false but R is true.

Reason — A is false as genetic diseases like haemophilia and thalassemia are not transmitted only from mothers. They are inherited through genes from both parents, depending on whether the disease is sex-linked (like haemophilia on the X chromosome) or autosomal (like thalassemia).
R is true because in sex-linked genetic diseases like haemophilia, the father’s chromosomes may not directly pass the disease to sons, but they still contribute to inheritance (especially daughters as carriers). So the statement that father’s chromosomes do not play a role is considered partially true in simplified school biology explanations.

Therefore, A is false but R is true is the correct option.

Both A and R are true and R is the correct explanation of A.

Reason — A is true as night blindness is a deficiency disease in which a person cannot see properly in dim light or at night due to lack of vision adaptation.
R is true as night blindness is caused by deficiency of Vitamin A. Foods like carrots, papayas, and other yellow/orange fruits and vegetables are rich in Vitamin A.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Both A and R are true and R is the correct explanation of A.

Reason — A is true as mumps is a viral infectious (communicable) disease that causes swelling and pain in the parotid salivary glands.
R is true as the mumps virus infects the salivary glands, leading to inflammation and swelling.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

Both A and R are true and R is the correct explanation of A.

Reason — A is true as malaria is caused by the parasite Plasmodium, which enters the human body through the bite of an infected female Anopheles mosquito.
R is true as Plasmodium completes its life cycle in two hosts - Anopheles mosquitoes and human beings.

Therefore, Both A and R are true and R is the correct explanation of A is the correct option.

(a) Iron
(b) Rickets
(c) Goitre
(d) Proteins

(a) Jaundice
Reason — Jaundice is caused by a virus while others are bacterial diseases.

(b) Malaria
Reason — Malaria is caused by a protozoan while others are viral diseases.

(c) Polio
Reason — Polio is a viral disease while others are vitamin deficiency diseases.

(d) Cancer
Reason — Cancer is a disease while others are food components.

(a) Cholera
(b) Malaria
(c) Elephantiasis
(d) Rabies/Hydrophobia
(e) Kwashiorkor and Marasmus
(f) Typhoid, Cholera, Jaundice
(g) Trachoma and Conjunctivitis
(h) Tobacco and Alcohol
(i) Typhoid and Cholera
(j) Malaria and Amoebiasis
(k) Viral fever and Chicken pox

(i) Vitamin A — Retinol
(ii) Vitamin B₁ — Thiamine
(iii) Vitamin B₃ — Niacin
(iv) Vitamin C — Ascorbic acid
(v) Vitamin D — Calciferol

(i) Filariasis (Elephantiasis)
(ii) Tetanus
(iii) Cholera
(iv) Amoebiasis
(v) Malaria

(i) Two examples of Metabolic diseases are — diabetes, and kidney stones.

(ii) Two examples of Genetic diseases are — Haemophilia, and thalassemia.

(iii) Two examples of Allergies are — Hay fever and Asthma.

(iv) Two examples of Dietary deficiency diseases are — Beri-Beri and Scurvy.

(v) Two examples of Cancer are — Breast cancer, and Leukemia.

(i) True
Reason — Malaria is a disease caused by a protozoan transmitted by mosquito bites, making it an infectious disease.

(ii) False
Reason — Rickets is caused due to the deficiency of vitamin D.

(iii) False
Reason — Houseflies, not viruses carry germs from garbage and sewage. Viruses infect cells and replicate within them.

(iv) True
Reason — Filarial germs are transmitted by the bite of female Culex mosquito.

(v) True
Reason — Nightblindness is the Vitamin A deficiency disease in which people are not able to see at night even if light is available.

(i) Health — Health is defined as a state of complete physical, mental and social well-being, and not merely an absence of disease or infirmity.

(ii) Disease — Any physical or functional change in the body from a normal state which causes discomfort or disability is called a disease.

(iii) Pathogen — Pathogens are disease-causing germs (microorganisms) that have the potential to cause infectious diseases. For example, viruses, bacteria, protozoans etc.

(iv) Allergen — Allergens are substances that can trigger an unpredictable allergic reaction in individuals.

(v) Hygiene — Hygiene is defined as science and practice of maintaining good health.

1. Disease — Any physical or functional change in the body from a normal state which causes discomfort or disability is called a disease. Disease is a departure from normal health through structural or functional disorder of the body.

2. Pathogen — Micro-organisms which cause communicable diseases are called pathogens. These germs are transmitted through various agencies like air, insect bites, rodents, contaminated food or water, etc. Pathogens may be different kinds of bacteria, viruses, fungi, protozoa or worms.

3. Allergy — Allergy is an unpredictable reaction of the body to a particular substance called allergen. A few common allergens are dust, spores, pollens, certain clothes, particular medicines, cosmetics, etc. Asthma, Eczema, Diarrhoea, Vomiting, Nausea, etc. are some of the common allergic reactions.

The diseases which are caused either due to improper functioning of the body organs or due to the deficiency of certain minerals and vitamins in the body are known as non-communicable diseases. These diseases are not caused by any germ, therefore these diseases cannot spread from one person to another (i.e., they are non-transmissible). Examples — rickets, diabetes, heart diseases, etc.

A disease which is caused due to the deficiency of certain nutrients, vitamins and minerals in the diet is called a deficiency disease. Example - Anaemia, Goitre.

The diseases that can easily spread from an infected person to a healthy person through disease causing germs called pathogens are called communicable diseases.

Dirt and many disease causing pathogens get accumulated under the nails. It is difficult to remove them even if we wash our hands frequently. Biting nails may cause these pathogens to enter into our body through our mouth causing various diseases. Hence, biting nails should be strictly avoided.

Regular exercise keeps the body muscles active. It helps in the normal functioning of the heart and lungs and also in better circulation of blood. Proper rest helps the body repair, regenerate and recover.

Fast foods are rich in fats and carbohydrates and deficient in vitamins. Eating more fast foods results in the accumulation of fat in the body of children making them suffer from obesity.

We can control spreading of diseases by mosquitoes and houseflies by using repellents, throwing garbage in covered bins, avoiding stagnation of water and covering all the drains prevent breeding of mosquitoes.

Maintaining public hygiene prevents the spread of communicable diseases like Malaria, Dengue, Cholera, Diarrhoea, etc. Maintaining a clean environment controls the breeding of mosquitoes, houseflies and other pathogens. Hence, public hygiene is equally important as personal hygiene for good health and preventing diseases.

The solved cross word puzzle is shown below:

Indirect method of transmission of communicable disease are:

1. From items used by the infected person — Touching and sharing items like towels, handkerchiefs, combs, utensils, etc. of an infected person may spread the disease to a healthy person.
2. Contaminated food and water — Houseflies carry germs from garbage and sewage and deposit them on food. Contamination of drinking water even with little amount of faeces or dung can cause a number of diseases.
3. Droplets through air — The droplets coming out when a person infected with common cold, TB, etc. sneezes or coughs, transmit the disease causing germs through the air spreading the disease to more people.
4. Vectors or carriers — Houseflies, mosquitoes, rodents, etc. also carry disease causing germs.

Three ways to keep the environment clean are:

1. Maintain a clean environment to prevent the spreading of diseases due to the breeding of mosquitoes, houseflies and pathogens.
2. Garbage should be kept in covered bins so that flies do not breed on it.
3. There should be proper sewer lines connected to sewage treatment plants.

Differences between Elephantiasis and Malaria on the basis of the mode of transmission:

Differences between Jaundice and Tuberculosis on the basis of the affected organs:

Differences between Rickets and Smallpox on the basis of the characteristic symptoms:

Differences between Anaemia and Goitre on the basis of the deficient mineral:

Differences between Metabolic diseases and Mental illness on the basis of the one example of each:

(i) Communicable diseases are diseases that can easily spread from an infected person to a healthy person through disease-causing germs called pathogens.

(ii) Cough and cold are caused by virus.

(iii) It spreads through water droplets introduced into the air during sneezing and coughing.

(iv) Two examples of non-communicable diseases are diabetes and cancer.