Two kinds of disease
A disease is a condition that stops the body from working normally. Diseases can be divided into two main groups: infectious and non-infectious.
Infectious diseases
An infectious disease is caused by tiny living things called pathogens, such as bacteria, viruses, fungi and protozoa. Infectious diseases can spread from one person to another. They may spread through:
- Air — coughing and sneezing (e.g. influenza, tuberculosis).
- Water or food — dirty water or unclean food (e.g. cholera, typhoid).
- Contact — touching an infected person or their things (e.g. ringworm).
- Animals (vectors) — mosquitoes carrying pathogens (e.g. dengue, malaria).
Key idea
Infectious diseases are caused by pathogens and can spread from person to person. Non-infectious diseases are not caused by pathogens and do not spread.
Non-infectious diseases
A non-infectious disease is not caused by pathogens and cannot spread between people. Causes include poor diet, an unhealthy lifestyle, or something inherited from parents. Examples are diabetes, heart disease, asthma and scurvy.
Example
Dengue is infectious — it spreads when an Aedes mosquito bites an infected person and then a healthy person. Diabetes is non-infectious — you cannot catch it from a friend.
Remember
- Infectious = caused by pathogens, can spread.
- Non-infectious = not caused by pathogens, cannot spread.
- Good hygiene and clean water help prevent infectious diseases.