Infectious diseases are also called communicable diseases or transmissible diseases. The most common causes of these ailments are pathogens that spread from one body to another, growing and multiplying in numbers eventually disrupting the normal cell functions.
Depending upon the pathogens or micro-organisms that cause the infectious diseases, they can be classified into four major groups:
- Viral infections
- Bacterial infections
- Protozoan infections
- Fungal infections and worm infestations
Availability of vaccines and immunisations have successfully helped in dealing with several infectious diseases like cholera, diphtheria, measles, mumps etc.