Diseases
* Health is a state of physical, mental and social well being.
* Disease is an unhealthy condition caused by microorganisms, improper diet or is inherited.
* Bacteria cause diseases like typhoid, cholera, tuberculosis and anthrax.
* Viruses cause the common cold, influenza, dengue fever, AIDS and rabies.
* Fungi cause skin infections.
* Protozoa causes malaria.
* Worms cause elephantiasis.
* The AIDS virus attacks the immune system and damages its function.
Transmission of Diseases
* Air, water, food, physical contact and vectors are means of transmission of infectious diseases.
* Prevention of diseases is more desirable than its successful treatment.
* Availability of proper and sufficient food for everybody is a basic principle of prevention of infectious diseases.
* Immunization is another way to prevent infectious diseases.
* Infectious diseases can be prevented by providing public hygiene and immunization to everyone.