Infectious diseases are disorders caused by organisms, such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. While they’re normally harmless or even helpful, some organisms under certain conditions may cause disease.
Some infectious diseases can be passed from person to person. Some, however, are transmitted by bites from insects or animals. Others are acquired by ingesting contaminated food or water or other exposures 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 infectious diseases.
Each infectious disease has its own specific signs and symptoms. General signs and symptoms common to many infectious diseases include:
- Loss of appetite
- Muscle aches