Infectious diseases are disorders caused by organisms — such as bacteria, viruses, fungi or parasites. Many organisms live in and on our bodies. They're normally harmless or even helpful, but under certain conditions, some organisms may cause disease.
Some infectious diseases can be passed from person to person. Some are transmitted by bites from insects or animals. And others are acquired by ingesting contaminated food or water or being exposed to organisms in the environment.
Signs and symptoms vary depending on the organism causing the infection, but often include fever and fatigue. Mild complaints may respond to rest and home remedies, while some life-threatening infections may require hospitalization.
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.
July 23, 2014
- Understanding microbes in sickness and in health. National Institute of Allergy and Infectious Diseases. http://www.niaid.nih.gov/topics/microbes/Pages/default.aspx. Accessed May 20, 2014.
- McPhee SJ, et al., eds. Pathophysiology of Disease. 6th ed. New York, N.Y.: The McGraw-Hill Companies; 2010. http://accessmedicine.mhmedical.com/content.aspx?bookid=339&Sectionid=42811304. Accessed May 20, 2014.
- Levinson W. Review of Medical Microbiology & Immunology. 12th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://accessmedicine.mhmedical.com/content.aspx?bookid=400&Sectionid=42098466. Accessed May 20, 2014.
- Longo DL, et al. Harrison's Online. 18th ed. New York, N.Y.: The McGraw-Hill Companies; 2012. http://www.accessmedicine.com/resourceTOC.aspx?resourceID=4. Accessed May 20, 2014.
- Walker BR, et al., eds. Davidson's Principles and Practice of Medicine. 22nd ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2014. http://www.clinicalkey.com. Accessed May 22, 2014.
- Stopping the spread of germs at home, work & school. Centers for Disease Control and Prevention. http://www.cdc.gov/flu/protect/stopgerms.htm. Accessed May 22, 2014.
- Basics for Handling Food Safely. U.S. Department of Agriculture. http://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/basics-for-handling-food-safely/ct_index. Accessed May 22, 2014.
- Sexually transmitted diseases (STDs). Centers for Disease Control and Prevention. http://www.cdc.gov/std/prevention/default.htm. Accessed May 22, 2014.
- Viral meningitis. Centers for Disease Control and Prevention. http://www.cdc.gov/meningitis/viral.html#transmission. Accessed May 22, 2014.