The different categories of diseases based on the extent of occurrence are:
- Epidemic diseases – diseases breaks out and spreads from place to place affecting a huge group of people at the same time
- Endemic diseases – this disease is found in a particular area only attacking less number of people. Example – yellow fever in some African countries
- Pandemic diseases – diseases widely spread throughout the world. Example – AIDS
- Sporadic diseases – Scattered individual case of a disease. Example – Malaria
