Classwork Series and Exercises {Basic Science – JSS1}: Disease Prevention

Basic Science JSS 1 Week 9

Topic: Disease Prevention (Clean Water)


This refers to the ways by which the spread of diseases is reduced or eradicated. It also deals with the strict and careful measures we adopt to ensure healthy living.

Water-Borne Diseases

Water-borne diseases are those diseases that are spread through water medium. They include cholera, diarrhea, typhoid, etc.


Cholera is a tropical infectious disease caused by a bacterium known as Vibrio cholerae. It infects the intestinal tract of humans resulting in frequent stooling (diarrhea) usually accompanied with acute vomiting and abdominal pains.

The excreta become very watery and full of bacteria. Cholera is also known as “rice water stool” because of the appearance of the stool of the patient. Cholera is spread by contact or in-take of contaminated water or food. It can also be spread by direct contact with the faeces, urine or oral discharge of infected persons. Cholera can be spread by houseflies.

Cholera is characterized by severe stomach upset, pains, frequent vomiting and passing of watery faeces (diarrhea), dehydration and fatigue. If adequate treatment is not taken, it can kill within three to five days. Cholera can be prevented through:

  1. Personal hygiene and cleanliness
  2. Boiling of water before drinking


This is a water-borne disease that results from drinking water infected by causative bacteria. This illness causes the waste matter to be emptied from the bowel (in liquid form) much more frequently than normal.

Diarrhoea is characterized by frequent stooling and vomiting and can be controlled through:

  1. Personal and proper environmental sanitation.
  2. Boiling of drinking water, etc.
  3. Covering of food to avoid contaminated.


Typhoid is caused by the bacterium known as Salmonella typhi. Typhoid is characterized by fever, severe pains in the bowel and bloody diarrhea due to ulceration of the intestinal wall.

The mode of transmission and control measures are similar to that of cholera.

Sources of Clean Water

Clean water is that which has no impurities in it. It has no colour, taste or odour. Sources of clean water include rain and spring water.

Water Treatment Processes

This refers to the various ways of making impure water pure and fit for use. It includes the following methods:

  1. Filtration: is the removal of solid particles and suspensions from water using a sieve with tiny openings. It does not ensure perfect purity of water because some micro-organisms can still pass through the opening.
  2. Boiling: This process involves heating water up to its boiling point (i.e. temperature at which it changes freely into water vapour) which is 100oC. Boiling water to a high temperature range kills the micro-organisms in it. It is a better method of purifying water than filtration.
  3. Use of Chemicals: This is the most effective method of purifying water. The public water system is treated with chemicals like chlorine which can kill and prevent the reproduction and growth of micro-organisms.

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