A communicable disease is a disease that spreads from one person to another, or from an animal, surface, or food to a person. They may also be referred to as transmissible or infectious diseases.
Disease-causing agents can include pathogens such as bacteria, viruses, fungi, parasites, protozoa, and prions. How these pathogens spread may vary, but some methods of transmission include:
- Contact with a contaminated object or surface, food, blood, or water
- Physical contact with an infected person through touch, sexual intercourse, droplets, or fecal/oral transmission
- Breathing in an airborne virus
- Bites from animals or insects
Some common examples of communicable diseases include:
- Hepatitis B
- Sexually transmitted diseases
The severity of the communicable disease varies, with some causing no symptoms while others can be severe and fatal.