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Fighting Disease:
Health At The End Of The Millennium
Another Wired Curriculum from The United Nations CyberSchoolBus

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Table of Contents

Unit 1: Introduction
  • Infectious diseases affect everyone: they include everything from the 'flu' to deadly diseases such as Ebola.
  • Once thought to have been under control, infectious diseases are back on the attack.
  • New diseases with no known cure are continue to emerge. About 30 new diseases have been identified in the past 20 years.
  • Old diseases that once seemed under control -- such as diphtheria and tuberculosis -- are causing problems again. These re-emerging diseases are developing resistance to drugs that once cured us of their effects.
  • New and re-emerging diseases are problems all over the globe and are not limited to one region. Infectious diseases are the leading cause of death in the world.
  • The two problems of new and re-emerging diseases require that we approach disease prevention and treatment with renewed vigour.

Unit 2: How infectious diseases work
  • Diseases are caused by microbes, mainly bacteria, protozoan and viruses. These are known as pathogens.
  • Bacteria are referred to by their shapes. Bacillus are rod-shaped; cocci are round; spirilla are spiral. Unlike viruses, many bacteria are, in fact, essential to our well-being.
  • Viruses must enter a cell in order to survive. Once inside a cell, they multiply and kill the host cells causing the symptoms of the infection.
  • The body has three main lines of defense against pathogenic invasion: unbroken skin and mucus membranes; white-blood cells; antibodies, produced by B cells, and T cells.
  • Vaccines work by making the body generate anti-bodies against a specific infection and thus boost immunity.
  • Anti-biotic drugs, used only for bacterial infections, are taken after an infection has already spread. Antibiotics help the body rid itself of the bacteria. But they also help control the spread of diseases to non-infected people.

Unit 3: Modes of Transmission
  • Viruses, bacteria and other pathogens enter our body in numerous ways: through our respiratory system, digestive system or breaks in our skin, for example.
  • Some diseases such as influenza and tuberculosis are spread through droplets of moisture (produced by coughing or sneezing for instance) that we inhale.
  • Some diseases such as cholera, dysentery and typhoid are spread through unsafe water (contaminated by sewage, for instance).
  • Some diseases such as malaria, dengue and yellow fever are spread by insects (any animal that spreads infectious agents is referred to as a vector).
  • Some diseases, such as HIV/AIDS and leprosy, are transmitted from person to person.

Unit 4: Poverty and disease
  • Poverty exposes hundreds of millions of people to the hazard of infectious diseases.
  • Lack of clean water and inadequate sanitation are breeeding grounds for infectious diseases. In developing countries, 1.1 billion people lack access to safe drinking water and some 2.9 billion people have inadequate sanitation.
  • This is compounded by rapid urbanization which forces people to live in unhygienic and overcrowded conditions.
  • Poverty also leads to malnutrition which diminishes the body's immune system.

Unit 5: Prevention
  • Preventive measures can be taken in a number of ways. Vaccination is only one such method (immunization campaigns will be discussed in the next unit).
  • Keeping a healthy, well-nourished and well-hydrated body is the first method of warding off disease.
  • Keeping living eco-systems intact avoids the spread of new diseases to humans. Some propose that a number of new diseases have emerged because eco-systems in some regions were suddenly disturbed by large projects such as road-building.
  • Health education is another method with which the spread of diseases and their harm can be limited. The more people know about how diseases are spread and why, the more preventive measures they can take.
  • Among the biggest killers of infants are diarrhoeal diseases caused by infections. The condition itself may not be deadly; it is the secondary effect that often kills: dehydration. Oral Rehydration Treatment (ORT) is an easy and cheap method of preventing this.
  • National health systems should offer protection against the spread of diseases. In some cases, health systems have collapsed because of the social and economic crises affecting many countries.

Unit 6: Immunization
  • Proper immunization can help keep diseases under control.
  • To date, only one infectious disease -- smallpox -- has been eradicated due to immunization efforts. Polio is targeted for eradication by the year 2000.
  • The World Health Organization spearheads many global immunization campaigns, often with the help of other UN agencies, such as UNICEF, governments and non-governmental organizations, such as Rotary International.
  • The Expanded Programme on Immunization, launched by WHO in 1974, has raised the immunization rate of children around the world from 5% to 80%. It aims to raise the percentage to 90 by the year 2000. The targets are the six vaccine-preventable diseases that affect children most: diphteria, pertussis (whooping cough), tetanus, poliomyelitis, measles and tuberculosis.
  • Immunization is a cheap and cost-effective method of disease control. Immunization against the six vaccine-preventable diseases is estimated at US$0.50 per capita in low-income countries.
  • Polio vaccines cost US$0.08. The cost of eradicating the disease by the year 2000 is estimated by WHO at $500,000 per year. The potential savings in terms of treatment of infected persons are estimated at $1.5 billion per year.

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