1. Infectious Disease is a disease that can be spread directly or indirectly from one living thing to another, such as meningitis, malaria, and influenza (the flu).
Note: Emerging infectious disease: An illness that presents new challenges in the 21st century and has one of the following characteristics:
- Previously unknown or not affecting enough people to get attention.
- Familiar but now affecting far more people.
- Appearing in new or unexpected regions.
- Resistant to antibiotics that once controlled it.
2. An infectious disease, or communicable disease, is caused by the entrance of organisms (e.g. viruses, bacteria, fungi) into the body which grow and multiply there to cause illness. Infectious diseases can be transmitted, or passed, by direct contact with an infected individual, their discharges (e.g. breath), or with an item touched by them.
(2006, Pandemic Influenza Business Continuity Guide & Template for San Francisco Businesses. San Francisco Department of Public Health. Communicable Disease Control and Prevention Section.)