Infectious diseases are disorders caused by either bacteria, viruses, fungi or parasites. Some infectious diseases might be passed from person to person, while some others might be caused by consuming contaminated food or water or being exposed to organisms in the environment. Many infectious diseases, such as measles and chickenpox, can be prevented by vaccines. Frequent and thorough hand-washing also helps protect you from most infectious diseases.
Each infectious disease has its own specific signs and symptoms. However, the following are general symptoms that can be seen in most conditions:
How are infectious diseases transmitted?
Most infectious diseases have only minor complications, however, some — such as pneumonia, hepatitis B and C, AIDS and meningitis — can become life-threatening. Some infectious diseases may become silent, only to appear again in the future.