The control of harmful microbes include removal, inhibition of growth or killing by physical agents/processes and chemical agents or antibiotics. Some common methods of controlling harmful microorganisms in order to maintain good health include

  1. High and low temperature: Boiling or heating of food, pasteurization of milk, sterilization of medical instruments and freezing of food to reduce the activities of microbes to barest minimum.
  2. Covering of food to prevent vectors and pathogens in the air from coming in contact with the food.
  3. Antibiotics such as amphiclox, ampicillin, penicillin, tetraclycline, are drugs used to kill many bacteria causing diseases.
  4. Antiseptic such as dettol, Milton, chlorine water, medicated soap and hydrogen peroxide destroy micro-organisms while others prevent the multiplication of the micro-organisms.
  5. Disinfectants are stronger antiseptic. Examples are sanitas, Lysol and izal. They are used to disinfect hospitals warehouses and public buildings. Antiseptics and disinfectant have to be diluted to render them gentle or mild to the skin
  6. High salinity (salting): Salt is used to preserve food. When salt is applied to food items like fresh meat or fish, the micro-organisms are destroyed. The bacterial cells are plasmolysed due to the movement of water from the cells of the bacteria.
  7. Dehydration: When foodstuffs such as fish and meat are dried, micro-organisms cannot thrive on them. Bacteria need water to survive. So dehydration prevents the survival of micro-organisms.
  8. Sanitation: Keeping the body and the environment clean.
  9. Isolation of infected persons: Persons suffering from infectious diseases such as tuberculosis and cholera must be isolated so as to prevent the spread of such diseases to other members of the community.
  10. Balanced diet: Eating balanced diet everyday helps to promote good health and high body resistance to diseases.



  1. Describe five ways of controlling harmful microorganisms.
  2. What method is most effective in microbial control.


A vector is an animal which transmits disease-causing organisms (pathogens) from the victim of that disease to another person.

Control of mosquitoes

  • Draining of swamps
  • Clearing of bushes around houses
  • Sleeping in a room protected by mosquito net.
  • Spray swamps or rooms with insecticides.
  • Spray oil on stagnant water.
  • Using insect repellant on body.
  • Use of drugs
  • Burying broken pots and cans.

Control of Houseflies

  • Spraying with insecticides
  • Destruction of breeding spots
  • Use of poison baits
  • Closing of pit toilets
  • Covering of food
  • Keeping environment clean.


  1. List four ways each of controlling black fly, tse-tse fly and rodents
  2. Explain other ways mosquitoes can be control.


There are many ways of maintaining good health.  These include:

  1. Refuse disposal: Refuse are solid waste materials discharged through human activities from homes and industries into the environment. Reckless refuse dump around dwelling places creates bad odour, provides breeding grounds for insects and rodents that spread diseases. Refuse disposal can be done through the following ways; Provision of dust bins in strategic locations, Burning of refuse in incinerators, Dumping them in isolated areas far from human habitation, Burying refuse in sanitary landfill.
  2. Sewage disposal: Sewage are waste water materials discharged from laundries, kitchen, toilets, bathrooms e.g. urine and faeces. Sewage disposal is done through the use of pit toilets where faeces and urine are passed into deep pits,the use of septic tanks where water is used to flush faeces and urine into a big tank dug in the ground, community treatment process where sewage from various homes are collected and treated before being discharged into the oceans or rivers.
  3. Protection of water: In view of various diseases which man contact because of drinking unclean water, water should be protected through the following ways: addition of alum to water, boiling of water before drinking, filtration of water on cooling, addition of chlorine to kill microscopic germs,storage of water in clean containers.
  4. Protection of food: The following methods of food protection are recommended: Keep food in refrigerators or deep freezers, boil or cook raw food properly before eating, there should be inspection of food meant for public consumption, washing of hands before and after eating of food, food should be preserved through canning, keep the environment where the food is prepared clean, avoid exposure of food to flies and other micro-organism.


  1. State four ways of purification of water
  2. Differentiate between refuse and sewage


The administration of health services in Nigeria is achieved through the following approved organizations:

  1. Ministry of Health
  2. University Teaching Hospitals

Countries cooperate to tackle health issues. At international level, health control is organized top prevent the spread of diseases and also to provide aid to needy areas. This can be in the form of drugs, medical equipments, money, etc.

International Health Organizations include: World Health Organization (WHO), United Nations Children’s Fund (UNICEF), International Red Cross (IRC), United Nations Educational, Scientific and Cultural Organization (UNESCO).

World Health Organization (WHO)

This is the world’s principal agency for dealing with health and nutritional problems. It was established in 1964 and became operational in 1948. The functions of WHO are as follows:

  • It provides and assists national governments at their request to strengthen their health services.
  • It promotes and provides improved methods of training health, medical related professional experts for member countries.
  • It promotes cooperation among scientific and professional bodies for the improvement of health.
  • It cooperates with other organizations in the improvement of nutrition, sanitation, housing working conditions and other matters that relate to health.
  • It helps and promotes material and children’s health care and welfare.
  • It produces medical publications.
  • It provides drugs and vaccines in cases of emergency

United Nations Children’s Fund (UNICEF)

This is a body set up by the U.N. It performs the following functions:

  • It provides emergency needs for children in areas affected by diseases or famine.
  • It improves the nutritional condition of undernourished children.
  • It feeds and cares for disabled children.
  • It undertakes immunization programmes for children’s diseases like measles, whooping cough, etc.
  • It ensures the provision of clothing and other needs for children

International Red Cross

This is a humanitarian organization whose functions are to serve humanity during peace and war times. During war, it performs the following functions:

  • Care for the injured.
  • Provision of emergency aid.
  • Negotiating for the exchange of the prisoners of war.
  • Evacuation of refugees.
  • Welfare of war prisoners.

United Nations Educational, Scientific and Cultural Organization (UNESCO)

Although, this is not directly a health organization, it assists health services indirectly by raising the educational standards of the people in developing countries.


  1. List three Health organization and outline four roles of each.
  2. Write short note on the life cycle of plasmodium.


  1. State five roles of UNICEF as a health organization
  2. State five roles of World Health Organization
  3. What is pasteurization?
  4. What is quarantine?
  5. Outline four general methods of controlling vectors


  1. A way of providing good health in a community is (a) control of diseases  (b) sewage disposal    (c) refuse disposal    (d) all of the above
  2. Which of these is not a vector? (a) Black fly     (b) Snake    (c) Dog      (d) Housefly
  3. The process of heating liquid food at a controlled temperature thereby enhancing its quality and destroying harmful micro-organisms (a) Pasteurization    (b) Boiling     (c) Frying       (d) None of the above
  4. An agent that stops the growth of fungi is called (a) fungistat (b) fungicide                        (c) germicide (d) none of the above
  5. The process by which water is removed from bacteria cells which leads to the cell been plasmolysed is referred to as (a) drying     (b) salting     (c) dehydration                    (d) pasteurization


  1. Name the causative organism and vector of Malaria
  2. List five symptoms of Malaria
  3. Mention five ways by which mosquito can be control and state the reason for each method


See also






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