Infectious diseases are mainly caused by micro-organisms like bacteria, viruses, fungi or parasites. some of these organisms cause diseases. Than any other cause infectious diseases kill more people throughout the world. These infections are mainly caused by germs .we can get infected by touching, eating, drinking or breathing something. Germs can also spread through animal and insect bites, sexual contact. Some of the diseases like measles and chickenpox can also be prevented by vaccines. Hand washing is also a used to prevent infectious diseases.