From WikiProjectMed
Jump to navigation Jump to search
Area of ringworm infestation on the calf (left lower leg)
SpecialtyInfectious disease

Infestation is the state of being invaded or overrun by pests or parasites.[1] It can also refer to the actual organisms living on or within a host.[2]

External and internal

Infestations can be classified as either external or internal with regards to the parasites' location in relation to the host.

External or ectoparasitic infestation is a condition in which organisms live primarily on the surface of the host (though porocephaliasis can penetrate viscerally) and includes those involving mites, ticks, head lice and bed bugs.[3]

An internal (or endoparasitic) infestation is a condition in which organisms live within the host and includes those involving worms (though swimmer's itch stays near the surface).

Medically, the term "infestation" is often reserved only for external ectoparasitic infestations[4] while the term infection refers to internal endoparasitic conditions.[5]


In general, the term "infestation" refers to parasitic diseases caused by animals such as arthropods (i.e. mites, ticks, and lice) and worms, but excluding (except) conditions caused by protozoa, fungi, bacteria, and viruses,[6] which are called infections.


  1. "infestation" at Dorland's Medical Dictionary
  2. "Infestation - Definition and More from the Free Merriam-Webster Dictionary". Archived from the original on 2021-08-06. Retrieved 2021-10-17.
  3. "Bed Bug Information". 2013-03-04. Archived from the original on 2021-10-17. Retrieved 2021-10-17.
  4. "Bedbugs". Skin Problems & Treatments Health Center. Archived from the original on 2013-11-21. Retrieved 2013-11-20.
  5. Leland S. Shapiro; Leland Shapiro (2005). Pathology and parasitology for veterinary technicians. Cengage Learning. pp. 111-. ISBN 978-1-4018-3745-7.
  6. Harvard Medical School; Anthony L. Komaroff (28 December 2004). Harvard Medical School Family Health Guide. Simon & Schuster. pp. 889–. ISBN 978-0-684-86373-3. Retrieved 24 April 2010.

External links