Class 9 Diseases: Cause and Control Mock Test (ICSE)

Topics in Diseases: Cause and Control

• Types of diseases
• Bacterial, viral and protozoan diseases
• Modes of transmission
• Prevention and control

Diseases: Cause and Control practice questions with answers

1. Q1Multiple choice·1 mark
   Which of the following is classified as a non-communicable, degenerative disease?

   1. (a)Tuberculosis
   2. (b)Arthritis
   3. (c)Cholera
   4. (d)Influenza
   Show answer and step marks

   1. Correct option: (b) Arthritis+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   Which of the following diseases is primarily transmitted through droplet infection released during coughing or sneezing?

   1. (a)Typhoid
   2. (b)Cholera
   3. (c)Tuberculosis
   4. (d)Malaria
   Show answer and step marks

   1. Correct option: (c) Tuberculosis+1

   Answer: (c)
3. Q3Multiple choice·1 mark
   Amoebic dysentery is caused by which category of infectious pathogen?

   1. (a)Bacterium
   2. (b)Virus
   3. (c)Protozoan
   4. (d)Fungus
   Show answer and step marks

   1. Correct option: (c) Protozoan+1

   Answer: (c)
4. Q4Short answer·2 marks
   Differentiate between water-borne and air-borne diseases on the basis of their mode of transmission. Give one example of each.
   Show answer and step marks

   1. Water-borne diseases spread through ingestion of contaminated water, whereas air-borne diseases spread through droplets in the air released by an infected person.+1
   2. Example of a water-borne disease, any one of: cholera; typhoid; hepatitis A; amoebic dysentery; or any other valid water-borne disease.+0.5
   3. Example of an air-borne disease, any one of: tuberculosis; influenza; common cold; measles; chickenpox; diphtheria; or any other valid air-borne disease.+0.5

   Answer: Water-borne diseases are transmitted through contaminated water (e.g. cholera or typhoid), while air-borne diseases are transmitted through droplets in the air (e.g. tuberculosis or influenza).
5. Q5Long answer·4 marks
   Answer the following questions regarding disease prevention and control: (a) Differentiate between active immunity and passive immunity, giving one suitable example for each. [2] (b) Mention two important community-level measures that should be adopted to prevent the spread of water-borne diseases. [2]
   Show answer and step marks

   1. (a) Active immunity: the body's own immune system produces antibodies after exposure to an antigen (infection or vaccine); it develops slowly but lasts long.+0.5
   2. (a) Example of active immunity, any one of: polio, measles or BCG vaccination; lasting immunity after recovering from measles or chickenpox; or any other valid example.+0.5
   3. (a) Passive immunity: ready-made antibodies are introduced into the body from an outside source; it acts at once but is short-lived.+0.5
   4. (a) Example of passive immunity, any one of: anti-tetanus serum (antitoxin) after an injury; anti-venom after a snake bite; antibodies passed from mother to baby through the placenta or breast milk; or any other valid example of ready-made antibodies.+0.5
   5. (b) First community measure, any one of: treating, filtering and chlorinating public water supplies; proper disposal of sewage away from water sources; protecting wells and reservoirs from contamination; regular inspection of food and water sold in public places; mass vaccination against typhoid or cholera during outbreaks; public health education on safe water; or any other valid community-level measure.+1
   6. (b) Second community measure, a different one from the same list.+1

   Answer: (a) Active immunity: the body makes its own antibodies (e.g. polio vaccination); passive immunity: ready-made antibodies are given from outside (e.g. anti-tetanus serum or antibodies in mother's milk). (b) Any two of: chlorinating public water supplies, proper sewage disposal, protecting water sources, inspecting food and water sold publicly, mass vaccination, health education.
6. Q6Long answer·4 marks
   Answer the following questions regarding the prevention and control of diseases: (a) Define immunization and state its significance in disease prevention. (b) Mention two preventive measures to control water-borne diseases like cholera and typhoid. (c) Explain why isolation of a patient suffering from an air-borne infectious disease is necessary. (d) State the importance of public awareness in controlling epidemics related to poor sanitation.
   Show answer and step marks

   1. (a) Immunization is the administration of a vaccine to stimulate the immune system to develop immunity against a specific pathogen.+0.5
   2. (a) Significance: it protects the person from future infection by that disease, and when most people are immunised the disease cannot spread in the community.+0.5
   3. (b) First preventive measure, any one of: drinking boiled or chlorinated water; proper disposal of human excreta and sewage; keeping food covered and away from flies; washing hands before eating and after using the toilet; avoiding cut fruit and uncovered food sold in the open; vaccination against cholera or typhoid; or any other valid measure.+0.5
   4. (b) Second preventive measure, a different one from the same list.+0.5
   5. (c) Isolation separates an infected individual from healthy people to prevent the direct or airborne transmission of pathogens during the communicable period.+1
   6. (d) Public awareness educates communities about hygiene practices, safe drinking water, and timely vaccination, ensuring collective participation in disease prevention and outbreak control.+1

   Answer: (a) Immunization is giving a vaccine so the body develops immunity to a specific disease; it prevents future infection and stops the disease spreading. (b) Any two of: boiled or chlorinated water, proper sewage disposal, covering food, washing hands, avoiding uncovered street food, vaccination. (c) It keeps the pathogens from spreading through the air to healthy people. (d) Awareness makes people follow hygiene, use safe water and get vaccinated, so outbreaks are controlled.

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