The conditions in which one or more organs of the body are not working properly, characterized by various signs and symptoms are called diseases.
The organisms which cause diseases are called pathogens
Diseases can be broadly classified into two types-
- Infectious diseases : Infectious diseases are those which are transmitted from an infected person to another healthy person.
- Non- infectious diseases : Non-infectious diseases are those which are not transmitted from an infected person to another person.
Infectious diseases includes-
- Bacterial diseases- caused by bacteria.
- Fungal diseases- causes by fungi.
- Viral diseases- caused by virus.
- Protozoan diseases- caused by protozoan.
- Helminth diseases- caused by helminth.