Human Health and Disease

Lesson

Part 1 — what health is, and the common infectious diseases, their causes and their prevention.

In this lesson you will

Explain what health means and what affects it
Describe the pathogens, symptoms and spread of common bacterial, viral, protozoan, helminth and fungal diseases
Trace the life cycle of Plasmodium
Explain how these diseases can be prevented and controlled

Concept

What affects health

Good health keeps people efficient and productive, increases longevity and reduces infant and maternal mortality. Balanced diet, personal hygiene and regular exercise help maintain it.

Table of three kinds of factors that affect health with examples
Factor	Example
Genetic disorders	Deficiencies with which a child is born
Infections	Diseases caused by pathogens
Lifestyle	Food and water, rest and exercise, habits

Concept

Bacterial diseases: typhoid and pneumonia

Disease-causing organisms are pathogens. Two important bacterial diseases:

Table comparing typhoid and pneumonia: pathogen, organ affected, symptoms, spread and notes
	Typhoid	Pneumonia
Pathogen	Salmonella typhi	Streptococcus pneumoniae, Haemophilus influenzae
Organ affected	Small intestine first, then other organs via blood	Alveoli of the lungs (fill with fluid)
Symptoms	Sustained high fever (39–40 °C), weakness, stomach pain, constipation, headache, loss of appetite; intestinal perforation in severe cases	Fever, chills, cough, headache; in severe cases lips and fingernails turn grey to bluish
Spread	Contaminated food and water	Droplets or aerosols from an infected person; shared glasses and utensils
Note	Confirmed by the Widal test	Severe breathing problems possible

Cookies