Diseases : Cause and Control - Questions & Answers

1. Match the diseases in Column I with their categories in Column II
Plague - Epidemic
Malaria - Sporadic
Goitre - Endemic
AIDS - Pandemic

2. Classify the following diseases into communicable and non-communicable diseases: cholera, beri-beri, colour blindness, diabetes, malaria, plague, heart-attack
Communicable diseases: cholera, malaria, plague
Non-communicable diseases: beri-beri, colour blindness, diabetes, heart-attack

1. Choose the correct answer from the options given below :

(i) A disease widely spread worldwide is known as :
(c) pandemic

(ii) Use of disposable syringes for injecting medicines, etc. is specially advised to prevent
(d) AIDS

(iii) The vector that transmits the malarial pathogen is :
(c) Anopheles mosquito

(iv) Amoebiasis is caused by the protozoan :
(d) Entamoeba

(v) BCG vaccine provides immunity against :
(d) Tuberculosis

(vi) The expanded form of AIDS is :
(b) Acquired Immuno Deficiency Syndrome.

(vii) Which of the following is not a nutritional deficiency disease?
(c) Thalassemia

(viii) Amoebiasis is caused by a :
(b) Protozoan

(ix) Which of following transmits the pathogens of sleeping sickness?
(d) Tsetsefly

(x) In hepatitis, the virus causes an inflammation of:
(c) Liver

(xi) Which of the following statements about HIV is correct ?
(b) HIV weakens the immune system, which can lead to cancer.

(xii) Tuberculosis is a disease in which a person suffers from persistent cough, fatigue and breathlessness. Which of the following statements do not hold true for the above mentioned disease ?
P It is a viral disease.
Q The disease is caused by a bacterium.
R The affected organs are the lungs.
S The disease can be prevented by triple vaccine (DPT).
(c) P and S

1. Correct the following statements by changing the first/last word only :

(a) Sporadic diseases are widely distributed worldwide.
Pandemic diseases are widely distributed worldwide.

(b) Yellow fever is an epidemic disease.
Yellow fever is an endemic disease.

(c) Chicken pox is caused by a bacterium.
Chicken pox is caused by a virus.

(d) Haemophilia is a kind of an allergy.
Asthma is a kind of an allergy.

(e) Ascariasis is caused by a tapeworm.
Ascariasis is caused by a roundworm.

2. Write the full forms of the following abbreviations:

(a) HIV
Human Immunodeficiency Virus

(b) AIDS
Acquired Immuno Deficiency Syndrome

(c) BCG
Bacillus Calmette-Guerin

(d) COVID-19
Coronavirus Disease 2019

(e) RNA
Ribonucleic Acid

3. Mention whether the following statements are true (T) or false (F).

(a) Filariasis is transmitted by the housefly. False

(b) Malaria is caused by a protozoan. True

(c) BCG vaccine is used for chicken pox. False

(d) Louis Pasteur discovered a cure for malaria. False

(e) AIDS is caused by a bacterium. False

(f) HIV is a serious disease, usually fatal. True

(g) AIDS is not transmitted by contact with a patient's clothes. True

(h) Chicken pox and hepatitis are bacterial diseases. False

(i) Goitre is endemic in sub-Himalayan regions of India. True

(j) AIDS is caused by a fungus. False

(k) Hay fever and asthma are allergies. True

(l) Smallpox still occurs in India. False

(m) The disease filariasis is caused by the bite of the female anopheles mosquito. False

4. Name the following :

(a) The vaccine for preventing tuberculosis BCG vaccine

(b) An organ usually affected by tuberculosis Lungs

(c) A disease that weakens body's defense system against infections AIDS

(d) The microorganism that requires a host to reproduce Virus

(e) The popular name of the disease filariasis Elephantiasis

5. Name :

(a) Four categories of diseases on the basis of their occurrence.
Endemic, epidemic, pandemic, sporadic.

(b) Two categories of diseases based on their communicability.
Communicable (infectious) and non-communicable (non-infectious) diseases.

(c) Two degenerative/ageing diseases.
Arthritis, cataract.

(d) Three diseases caused by protozoans.
Malaria, amoebic dysentery, sleeping sickness.

(e) Three diseases caused by helminths.
Ascariasis, taeniasis, filariasis.

6. The first pair indicates the kind of relationship that exists between the first two terms. Rewrite and complete the second pair on a similar basis :

(a) April 7 : World health day :: December 1 : World AIDS Day

(b) Malaria: Plasmodium :: Filariasis: Wuchereria bancrofti

(c) Hepatitis: Liver :: Tuberculosis : Lungs

(d) Mumps: Viral disease:: Typhoid : Bacterial disease

(e) Covid-19: Pandemic:: Yellow fever: Endemic disease

7. Match the terms given in Column A with those of column B:
(a) Allergy - (vi) Hay fever
(b) Metabolic disease - (v) Diabetes mellitus
(c) Genetic disease - (i) Thalassemia
(d) Degenerative disease - (ii) Cataract
(e) Cancer - (iii) Leukemia

8. Choose the odd one out and write the category for the remaining terms :

(a) Cholera, Typhoid, Malaria, Tuberculosis
Odd: Malaria. Category: Bacterial diseases.

(b) Hepatitis, Ascariasis, Chicken pox, Poliomyelitis
Odd: Ascariasis. Category: Viral diseases.

(c) Elephantiasis, Ascariasis, Taeniasis, Hepatitis
Odd: Hepatitis. Category: Helminthic (worm) diseases.

(d) Depression, Beri-beri, Scurvy, Night-blindness
Odd: Depression. Category: Nutritional deficiency diseases.

(e) Malaria, Amoebiasis, Sleeping sickness, Cataract
Odd: Cataract. Category: Protozoan diseases.

1. Define :

(a) Infection
The transmission of disease-causing germs from one person to another is called infection.

(b) Pathogen
A disease-causing organism is called a pathogen.

(c) Incubation period
The period between the entry of germs and the appearance of the first symptoms of the disease.

(d) Disease
A condition in which the normal functioning of the body is disturbed.

(e) Vaccine
A preparation (like dead or weakened germs) inoculated into the body to develop immunity against a specific disease.

2. Write the scientific names of the causative organisms for the following diseases :

(a) Cholera
Vibrio cholerae

(b) Typhoid
Salmonella typhi

(c) Tuberculosis
Mycobacterium tuberculosis

(d) Taeniasis
Taenia solium

(e) Filariasis
Wuchereria bancrofti

3. Name the causative germ of AIDS. How is this disease transmitted ?
The causative germ of AIDS is HIV (Human Immunodeficiency Virus). It is transmitted through sexual intercourse, contaminated blood transfusions, from mother to child during birth, and by sharing unsterilised injection needles.

1. Write very briefly about the following : BCG, Incubation period, Chicken pox, Hepatitis A
BCG: A vaccination (Bacillus Calmette-Guerin) found useful in developing immunity for tuberculosis.
Incubation period: The time interval between the receiving of the infection (entry of germs) and the appearance of the first symptoms of the disease.
Chicken pox: A contagious viral disease caused by Herpes virus 'Varicella zoster' mainly occurring in children, characterized by highly irritating rashes that rapidly change to watery blisters.
Hepatitis A: A viral disease causing inflammation of the liver, transmitted mainly by contaminated food and water, with an incubation period of 14 to 45 days.

2. What are the causes and symptoms of malaria, chicken pox and tuberculosis ? How can these diseases be prevented ?
Malaria: Caused by Plasmodium (protozoan). Symptoms include chills and high fever repeated on the third or fourth day. Prevented by destroying mosquitoes at all stages and avoiding mosquito bites using nets or repellants.
Chicken pox: Caused by Varicella zoster (virus). Symptoms include highly irritating rashes on the body that change to watery blisters and then scabs. Prevented by vaccination and avoiding close contact with infected persons.
Tuberculosis: Caused by Mycobacterium tuberculosis (bacterium). Symptoms include persistent cough, afternoon fever, bloody mucus, loss of weight, and fatigue. Prevented by BCG vaccination and isolation of the patient.

3. What are the different ways in which infectious diseases can spread ?
Infectious diseases can spread through air and dust (droplet infection), contaminated food and water, direct close contact with infected persons, insect vectors (like mosquitoes and flies), sexual contact, and contaminated blood transfusions or syringes.

4. Name any four non-infectious diseases and their causes.
1. Beri-beri (caused by nutritional deficiency).
2. Diabetes mellitus (caused by metabolic disorder).
3. Haemophilia (caused by genetic factors).
4. Hay fever (caused by allergies/allergens).

5. Distinguish between :

(a) Pandemic and sporadic diseases
Pandemic diseases are widely distributed worldwide (e.g., AIDS, COVID-19), whereas sporadic diseases involve scattered, individual cases of a disease (e.g., malaria, cholera).

(b) Communicable and non-communicable diseases
Communicable diseases are caused by germs and can spread from an infected person to a healthy person (e.g., cholera). Non-communicable diseases are not caused by germs and cannot be transmitted from one person to another (e.g., diabetes).

(c) Allergens and carcinogens
Allergens are agents that cause allergies (like dust or pollen), whereas carcinogens are agents that cause cancer (like tobacco smoking or radiation).

(d) Endemic and Epidemic diseases
Endemic diseases are found in a certain area only, attacking a fewer number of people (e.g., goitre in sub-Himalayan regions). Epidemic diseases break out and spread rapidly from place to place affecting large numbers of people at the same time (e.g., plague).

(e) Pathogen and Vector
A pathogen is a disease-causing organism (like a bacterium or virus), whereas a vector is an organism (like a mosquito) that transmits the germs from one person to another.

6. Write five important preventive measures advised by WHO to minimise the chances of getting COVID-19.
1. Staying at home.
2. Regularly washing hands with soap and water.
3. Avoiding crowded spaces.
4. Wearing a mask in public and maintaining a safe distance.
5. Getting vaccinated.

1. The diagram given below represents a kind of microorganism. Study the same and answer the following questions :

(a) Identify the microorganism.
HIV (Human Immunodeficiency Virus).

(b) To which category of microorganisms does it belong ?
Viruses.

(c) Label the guidelines 1, 2 and 3.
1 - Viral Protein, 2 - Protein Covering, 3 - RNA (Genetic material).

(d) Does it cause any disease? If yes, name the disease.
Yes, it causes AIDS (Acquired Immuno Deficiency Syndrome).

(e) Mention two ways by which it can be transmitted from one person to another.
1. Sexual contact.
2. Contaminated blood transfusion.

2. The figure shown below represents an animal. Answer the following questions.

(a) Identify and name the animal.
Tapeworm.

(b) Write the phylum to which it belongs.
Platyhelminthes (Flatworms / Helminths).

(c) Name the disease caused by this animal
Taeniasis.

(d) Write its scientific name.
Taenia solium

(e) Mention two common hosts (animals) for this parasite.
Man and Pig (or cow).

(Choose the answer based on the codes given below.)
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

(i) Assertion (A) : When the disease is widely distributed worldwide, it is termed as a sporadic disease.
Reason (R) : Sporadic diseases are not localised, their individual cases are scattered; for example malaria, cholera, etc.
(d) A is false but R is true.

(ii) Assertion (A) : Goitre is a kind of a nutritional deficiency disease as well as metabolic disease.
Reason (R) : Goitre is caused due to the deficiency of iodine and also due to the malfunctioning of thyroid gland.
(a) Both A and R are true and R is the correct explanation of A.

(iii) Assertion (A) : The disease-causing germs are called pathogens.
Reason (R) : The transmission of germs from one person to another is carried out by certain organisms which are termed as vectors.
(b) Both A and R are true but R is not the correct explanation of A.

(iv) Assertion (A) : Taeniasis is the disease caused by tapeworms. It spreads by eating infected pork or beef.
Reason (R) : Pigs or cows accidentally ingest the eggs of tapeworm which later on form larval stages. These larvae settle in the muscles of pigs or cows.
(a) Both A and R are true and R is the correct explanation of A.

(v) Assertion (A) : The viruses are extremely small substances made of nucleic acids (DNA) and histones.
Reason (R) : Viruses are considered as a connecting link between the living and non-living beings as they can multiply and be crystallized and stored for years.
(d) A is false but R is true.

1. During winter, Sneha noticed several of her classmates taking leave from school and staying home due to high fever, cough and body pain. Her teacher explained that these were symptoms of viral infections, which can spread easily from an infected person to a healthy person. Sneha also learned that diseases like common cold, flu and chicken pox are caused by viruses. Proper hygiene, vaccination and avoiding close contact with sick people can help us from falling sick.

(a) Categorise diseases on the basis of their communicability. Name them with one example of each.
Diseases are categorised into Communicable (Infectious) diseases, e.g., Chicken pox; and Non-communicable (Non-infectious) diseases, e.g., Diabetes.

(b) Define 'infection'.
The transmission of disease-causing germs from one person to another is called infection.

(c) Why do we consider viruses to be the connecting link between living beings and non-living beings? Explain with one major point.
Viruses are considered a connecting link because they exhibit characteristics of both. For example, they can multiply and behave like living beings inside a host cell, but outside a host cell, they cannot respire or multiply and can be crystallized like non-living substances.

(d) Distinguish between bacteria and viruses on the basis of cellular structure.
Bacteria are single-celled organisms, whereas viruses are acellular (they lack cellular structure and are extremely small substances made only of nucleic acids and proteins).

(e) Segregate viral diseases from the list given below: Mumps, scurvy, poliomyelitis, rabies, cholera, hepatitis, filariasis.
Viral diseases from the list are: Mumps, poliomyelitis, rabies, and hepatitis.