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Chapter Two
Diseases
FOR ONLINE READING ONLY
Introduction
Diseases make people unhealthy. In this chapter, you
will learn about human diseases. You will also learn how
diseases spread, their causes and how to prevent them.
You will also learn the life cycle of some insects that spread
various diseases. The competencies developed will enable
you to protect yourself and others from diseases.
The effects of diseases on human
Think
health
Concept of diseases
Disease is an abnormal condition or disorders in a living organism
that disrupts normal functioning of the body. Many diseases are
caused by germs found in our surroundings. These germs are
found in air, soil, water, unsafe food and animal bodily fluids like
blood. Germs can enter the body through eating contaminated
food, drinking unsafe water, breathing in contaminated air, or
touching an infected person. However, some diseases are not
caused by germs, such as hereditary diseases.
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