Diseases: Cause and Control

Match the diseases in Column I with their categories in Column II

Answer

Classify the following diseases into communicable and non-communicable diseases:

cholera, beri-beri, colour blindness, diabetes, malaria, plague, heart-attack

Answer

A disease widely spread worldwide is known as:

1. Endemic
2. Epidemic
3. Pandemic
4. Sporadic

Answer

Pandemic

Reason — A disease like COVID-19 and AIDS are pandemic as they affect whole world.
Endemic refers to a disease that is regularly found in a particular area. Epidemic is a disease that spreads rapidly but is limited to a specific region or population, not worldwide. Sporadic disease means a disease occurs irregularly and infrequently, not widely spread.

Use of disposable syringes for injecting medicines, etc. is specially advised to prevent

1. Poliomyelitis
2. Mumps
3. Rabies
4. AIDS

Answer

AIDS

Reason — Use of same syringe may increase the chance of spread of AIDS.
Poliomyelitis – spreads mainly through contaminated food and water. Mumps – spreads through droplets (coughing/sneezing). Rabies – spreads through the bite of infected animals.

The vector that transmits the malarial pathogen is:

1. Culex mosquito
2. Housefly
3. Anopheles mosquito
4. Entamoeba

Answer

Anopheles mosquito

Reason — The malarial pathogen Plasmodium, is transferred from an infected person to a healthy person through the bite of female Anopheles mosquito.
Culex mosquito mainly spreads diseases like filariasis, not malaria. Housefly spreads diseases by contaminating food but does not transmit malaria. Entamoeba histolytica is a protozoan causing amoebic dysentery, not a vector.

Amoebiasis is caused by the protozoan:

1. Amoeba proteus
2. Euglena
3. Plasmodium
4. Entamoeba

Answer

Entamoeba

Reason — Entamoeba hystolytica causes Amoebiasis.
Amoeba proteus is a harmless, free-living organism found in water. Euglena is a free-living organism that performs photosynthesis and does not cause disease. Plasmodium causes malaria, not amoebiasis.

BCG vaccine provides immunity against:

1. Tetanus
2. Cholera
3. AIDS
4. Tuberculosis

Answer

Tuberculosis

Reason — BCG vaccine provides immunity against Tuberculosis. The vaccine contains Mycobacterium bovis, which is similar to TB.
Tetanus – prevented by the Tetanus vaccine, not BCG. Cholera – prevented by specific oral cholera vaccines. AIDS – there is currently no widely used vaccine for AIDS.

The expanded form of AIDS is:

1. Active Immunity Deficiency Syndrome
2. Acquired Immuno Deficiency Syndrome
3. Acquired Immuno Deficiency Status
4. Active Immuno Deficiency Syndrome

Answer

Acquired Immuno Deficiency Syndrome

Reason — AIDS stands for Acquired Immuno Deficiency Syndrome.

Which of the following is not a nutritional deficiency disease?

1. Night Blindness
2. Beri-Beri
3. Thalassemia
4. Kwashiorkor

Answer

Thalassemia

Reason — Thalassemia is a genetic disease in which the body doesn't make sufficient haemoglobin.
Night blindness is caused by deficiency of Vitamin A. Beri-Beri is caused by deficiency of Vitamin B1 (thiamine). Kwashiorkor is caused by protein deficiency.

Amoebiasis is caused by a :

1. Bacteria
2. Protozoan
3. Virus
4. Metazoan

Answer

Protozoan

Reason — Amoebiasis is caused by Entamoeba hystolytica, a protozoan.
Amoebiasis is not caused by bacteria because bacteria are prokaryotic but causative agent is eukaryotic. Amoebiasis is not viral because, causative agent is a living single-celled organism but virus are non-cellular. Metazoans are multicellular animals, whereas the causative organism here is unicellular.

Which of following transmits the pathogens of sleeping sickness?

1. Housefly
2. Butterfly
3. Dragonfly
4. Tsetsefly

Answer

Tsetsefly

Reason — Tsetsefly transmits the pathogens of sleeping sickness.
Housefly can spread germs by contaminating food, but does not transmit sleeping sickness. Butterfly is harmless and not a disease vector. Dragonfly actually eats mosquitoes and is beneficial, not a disease carrier.

In hepatitis, the virus causes an inflammation of

1. Lung
2. Kidney
3. Liver
4. Stomach

Answer

Liver

Reason — In hepatitis, the virus causes an inflammation of liver.
Lungs are affected in diseases like pneumonia, not hepatitis. Kidneys are involved in urinary diseases, not hepatitis. Stomach infections are different (like gastroenteritis), not hepatitis.

Which of the following statements about HIV is correct?

1. HIV primarily attacks red blood cells, leading to anemia.
2. HIV weakens the immune system, which can lead to cancer.
3. HIV is caused by a bacterium and can be treated with antibiotics.
4. HIV infection is detectable immediately after exposure.

Answer

HIV weakens the immune system, which can lead to cancer.

Reason — HIV (Human Immunodeficiency Virus) attacks the body's immune system, particularly the white blood cells. Over time, this weakens the immune system, making the body vulnerable to opportunistic infections and certain types of cancer.
HIV does not attack red blood cells. It targets white blood cells (specifically CD4 cells), not RBCs. Antibiotics work only against bacteria, not viruses. HIV is managed using antiretroviral therapy (ART), not antibiotics. There is a window period after infection when the virus is not immediately detectable by tests. It usually takes a few weeks for antibodies/antigens to become detectable.

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).

(a) P and Q
(b) Q and R
(c) P and S
(d) Q and S

Answer

P and S

Reason —

P - Tuberculosis is caused by the bacterium Mycobacterium tuberculosis.

S - DPT vaccine protects against Diphtheria, Pertussis, Tetanus.

Q - Tuberculosis is caused by bacterium Mycobacterium tuberculosis.

R - Tuberculosis mainly affects the lungs, though it can sometimes spread to other organs.

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

(a) Sporadic diseases are widely distributed worldwide.

(b) Yellow fever is an epidemic disease.

(c) Chicken pox is caused by a bacterium.

(d) Haemophilia is a kind of an allergy.

(e) Ascariasis is caused by a tapeworm.

Answer

(a) Pandemic diseases are widely distributed worldwide.

(b) Yellow fever is an endemic disease.

(c) Chicken pox is caused by a virus.

(d) Haemophilia is a kind of genetic disease.

(e) Ascariasis is caused by a roundworm.

Write the full forms of the following abbreviations:

(a) HIV

(b) AIDS

(c) BCG

(d) COVID-19

(e) RNA

Answer

(a) HIV — Human Immunodeficiency Virus

(b) AIDS — Acquired Immuno Deficiency Syndrome

(c) BCG — Bacillus Calmette-Guerin

(d) COVID-19 — Corona Virus Disease 2019

(e) RNA — Ribo-nucleic Acid

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

(a) Filariasis is transmitted by the housefly.

(b) Malaria is caused by a protozoan.

(c) BCG vaccine is used for chicken pox.

(d) Louis Pasteur discovered a cure for malaria.

(e) AIDS is caused by a bacterium.

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

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

(h) Chicken pox and hepatitis are bacterial diseases.

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

(j) AIDS is caused by a fungus.

(k) Hay fever and asthma are allergies.

(l) Smallpox still occurs in India.

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

Answer

(a) False
Corrected Statement — Filariasis is transmitted by Culex Mosquito.

(b) True

(c) False
Corrected Statement — BCG vaccine is used for Tuberculosis.

(d) False
Corrected Statement — Louis Pasteur discovered Anthrax vaccine.

(e) False
Corrected Statement — AIDS is caused by a virus named HIV (Human Immunodeficiency Virus).

(f) True

(g) True

(h) False
Corrected Statement — Chicken pox and hepatitis are viral diseases.

(i) True

(j) False
Corrected Statement — AIDS is caused by a virus named HIV (Human Immunodeficiency Virus).

(k) True

(l) False
Corrected Statement — Small pox was eradicated from India in 1979.

(m) False
Corrected Statement — The disease filariasis is caused by the bite of culex mosquito.

Name the following:

(a) The vaccine for preventing tuberculosis ............... .

(b) An organ usually affected by tuberculosis............... .

(c) A disease that weakens body’s defense system against infections ............... .

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

(e) The popular name of the disease filariasis ............... .

Answer

(a) BCG

(b) Lungs

(c) AIDS

(d) Virus

(e) Elephantiasis

Name:

(a) Four categories of diseases on the basis of their occurrence.

(b) Two categories of diseases based on their communicability.

(c) Two degenerative/ageing diseases.

(d) Three diseases caused by protozoans.

(e) Three diseases caused by helminths.

Answer

(a) Endemic, Epidemic, Pandemic, Sporadic

(b) Communicable and Non-communicable

(c) Arthritis, Cataract

(d) Malaria, Amoebic Dysentery, Sleeping Sickness

(e) Ascariasis, Taeniasis, Filariasis

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 : ...............

(b) Malaria: Plasmodium :: Filariasis : ...............

(c) Hepatitis: Liver :: Tuberculosis : ...............

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

(e) Covid- 19: Pandemic :: Yellow fever : ...............

Answer

(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.

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

Match the terms given in Column A with those of column B:

Answer

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

(a) Cholera, Typhoid, Malaria, Tuberculosis

(b) Hepatitis, Ascariasis, Chicken pox, Poliomyelitis

(c) Elephantiasis, Ascariasis, Taeniasis, Hepatitis

(d) Depression, Beri-beri, Scurvy, Night-blindness

(e) Malaria, Amoebiasis, Sleeping sickness, Cataract

Answer

(a) Odd one out — Malaria
Cholera, Typhoid, Tuberculosis — Bacterial Diseases

(b) Odd one out — Ascariasis
Hepatitis, Chicken pox, Poliomyelitis — Viral diseases

(c) Odd one out — Hepatitis
Elephantiasis, Ascariasis, Taeniasis — Diseases caused by parasitic worms.

(d) Odd one out — Depression
Beri-beri, Scurvy, Night-blindness — Deficiency diseases

(e) Odd one out — Cataract
Malaria, Amoebiasis, Sleeping sickness — Protozoan disease.

Define:

(a) Infection

(b) Pathogen

(c) Incubation period

(d) Disease

(e) Vaccine

Answer

(a) Infection — The transmission of diseases from one person to another is called infection.

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

(c) Incubation — Incubation period is the period between the entry of germs and appearance of the first symptoms of the disease. All infectious diseases have a certain incubation period.

(d) Disease — Disease is a departure from normal health through structural or functional disorder of the body.

(e) Vaccine — Vaccine is a biological formulation that consist of dead or weakened disease causing organism that provides active acquired immunity to a particular infectious disease.

Write the scientific names of the causative organisms for the following, diseases :

(a) Cholera

(b) Typhoid

(c) Tuberculosis

(d) Taeniasis

(e) Filariasis

Answer

(a) Vibrio Cholerae

(b) Salmonella typhi

(c) Mycobacterium tuberculosis

(d) Taenia solium

(e) Wuchereria bancrofti

Name the causative germ of AIDS. How is this disease transmitted ?

Answer

The causative of AIDS is HIV (Human Immunodeficiency Virus).

Transmission of AIDS:

1. Sexual intercourse
2. Contaminated blood transfusions
3. Mother to child transmission
4. Injection needles

Write very briefly about the following:

(a) BCG

(b) Incubation period

(c) Chicken pox

(d) Hepatitis A

Answer

(a) BCG — BCG (Bacillus Calmette Guerin) is a vaccine which is effective against the bacterial disease tuberculosis(TB). It develops immunity to tuberculosis.

(b) Incubation period — Incubation period is the period between the entry of germs and appearance of the first symptoms of the disease. All infectious diseases have a certain incubation period.

(c) Chicken pox — The disease is a contagious disease occurring mainly in children, and is caused by Herpes Varicella zoster virus. The disease rapidly spreads through close contact with the person infected.

(d) Hepatitis A — It is caused by the Hepatitis A virus and is a viral disease that results in liver inflammation. It is transferred primarily through contaminated water and food.

What are the causes and symptoms of malaria, chicken pox and tuberculosis? How can these diseases be prevented?

Answer

The causes, symptoms and preventive measures of these diseases are as given below:

1. Malaria
   • Causes — Protozoan, Plasmodium.
   • Symptoms — Chills, high fever, profuse sweating, severe headache, nausea, vomiting, fatigue and body pain.
   • Preventive measures — Avoid mosquito bites using mosquito repellents and nets avoid being around stagnant water.
2. Chicken Pox
   • Causes — Virus, Varicella zoster.
   • Symptoms — Rashes near the back and the chest eventually spreading to arms, face, legs and head.
   • Preventive measures — Active immunisation by administering live attenuated vaccine containing Varicella.
3. Tuberculosis
   • Causes — Mycobacterium tuberculosis.
   • Symptoms — Persistent cough, afternoon fever, bloody mucus, loss of weight, fatigue and chest pain.
   • Preventive measures — BCG vaccination and isolation of the patient.

What are the different ways in which infectious diseases can spread?

Answer

The different ways in which infectious diseases can spread are as follows:

1. Direct contact — Person to person, animal to person and expected mother to child.
2. Indirect contact — Doorknob, phone, etc.
3. Droplet transmission — Sneezing, Coughing, etc.
4. Particle transmission — Air particles can transfer infectious diseases
5. Bites and Stings — Mosquitoes, lice, ticks, etc.
6. Food Contamination — Food, beverages, etc.

Name any four non-infectious diseases and their causes.

Answer

Distinguish between:

(a) Pandemic and Sporadic diseases

(b) Communicable and non-communicable diseases

(c) Allergens and carcinogens

(d) Endemic and Epidemic diseases

(e) Pathogen and Vector

Answer

(a) Difference between pandemic and sporadic diseases :

(b) Difference between communicable and non-communicable diseases :

(c) Difference between allergens and carcinogens :

(d) Difference between endemic and epidemic diseases :

(e) Difference between pathogen and vector :

Write five important preventive measures advised by WHO to minimise the chances of getting COVID-19.

Answer

Five important preventive measures advised by WHO to minimise the chances of getting COVID-19 are:

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.

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

(a) Identify the microorganism.

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

(c) Label the guidelines 1, 2 and 3.

(d) Does it cause any disease? If yes, name the disease.

(e) Mention two ways by which it can be transmitted from one person to another.

Answer

(a) Human Immunodeficiency Virus (HIV).

(b) Virus

(c) The labelled guidelines are :

• 1 → Viral Protein
• 2 → Protein covering
• 3 → RNA

(d) Yes, it causes the disease called Acquired Immuno Deficiency Syndrome (AIDS).

(e) Two ways by which it can be transmitted from one person to another are:

1. Sexual intercourse
2. Contaminated blood transfusions

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

(a) Identify and name the animal.

(b) Write the phylum to which it belongs.

(c) Name the disease caused by this animal.

(d) Write its scientific name.

(e) Mention two common hosts (animals) for this parasite.

Answer

(a) Tapeworm

(b) Platyhelminthes

(c) Taeniasis

(d) Taenia solium

(e) Cow and Pig

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.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is False and R is True.

Reason — A is false because a disease that is widely distributed throughout the world is called a pandemic, not a sporadic disease.
R is true because sporadic diseases occur irregularly and in scattered individual cases, rather than affecting a large population at the same time. Malaria and cholera are correct examples of sporadic diseases.

Therefore, A is False and R is True is the correct option.

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.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

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

Reason — A is true as goitre is an enlargement of the thyroid gland. It is caused by a deficiency of iodine, which is a nutritional deficiency. Since the thyroid controls metabolism through thyroxine production, goitre is associated with metabolic imbalance due to thyroid hormone deficiency.”.
R is true as goitre is caused due to a deficiency of iodine. Iodine is essential for the synthesis of thyroxine, the thyroid hormone.

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

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.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

Both A and R are true but R is not the correct explanation of A.

Reason — A is true as disease-causing germs are called pathogens (e.g., bacteria, viruses).
R is true as vectors like mosquitoes, houseflies, and ticks help in spreading pathogens. Example: Anopheles mosquito transmits Plasmodium (causes malaria).

Therefore, Both A and R are true but R is not the correct explanation of A is the correct option.

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.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

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

Reason — A is true as Taeniasis is caused by: Taenia solium (from infected pork) or Taenia saginata (from infected beef). Humans get the disease by eating undercooked or raw meat containing larval cysts of the tapeworm.
A is true as the tapeworm eggs, passed in human feces, can contaminate food or water sources. Pigs or cows ingest these eggs, which develop into larvae (cysticerci) in their muscles.

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

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.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Answer

A is False and R is True.

Reason — A is False as viruses are extremely small and are made of: A nucleic acid core (either DNA or RNA, never both), and a protein coat called a capsid. However, viruses do not contain histones.
R is true as viruses behave like living organisms when inside a host cell (they replicate), and like non-living things outside a host (they can be crystallized and stored without metabolism or reproduction).

Therefore, A is False and R is True is the correct option.

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.

(b) Define 'infection'.

(c) Why do we consider viruses to be the connecting link between living beings and living beings? Explain with one major point.

(d) Distinguish between bacteria and viruses on basis of cellular structure.

(e) Segregate viral diseases from the list below: Mumps, scurvy, poliomyelitis, cholera, hepatitis, filariasis.

Answer

(a) Diseases are mainly classified into two types on the basis of their communicability: communicable and non-communicable diseases.

(b) Infection is the condition in which disease-causing microorganisms enter the body, multiply, and cause harm to the host.

(c) Virus are considered a link between living and non-living because outside a host cell, they are inactive, non-living, and can even be crystallised but inside a host cell, they become active, multiply, and show life-like properties.
Thus, they show both living and non-living characteristics.

(d) Bacteria are living unicellular organisms whereas, viruses are acellular.
Bacteria have cell wall, cytoplasm, ribosomes whereas, viruses have only genetic material and protein coat.
Bacteria have their own metabolism whereas, viruses have no metabolism outside host.

(e) Mumps, Poliomyelitis, Hepatitis are the viral diseases.