View source for Parasitic disease

{{Infobox medical condition (new)
| name            = Parasitic disease
| image           = Malaria.jpg
| caption         = False-color [[electron micrograph]] of a ''[[Plasmodium]]'' [[sporozoite]]
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| field           = [[Infectious disease (medical specialty)|Infectious disease]]
| synonyms        = parasitosis, parasitic infection
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A '''parasitic disease''', also known as '''parasitosis''', is an [[infectious disease]] caused by [[Parasitism|parasites]].<ref>{{Cite EB1911 |wstitle=Parasitic Diseases |volume=20 |page=770 |first=German Sims |last=Woodhead}}</ref> Parasites are organisms which derive sustenance from its [[Host (biology)|host]] while causing it harm.<ref name=":1">{{Citation |title=Introduction to Parasitology |date=1996 |url=https://www.ncbi.nlm.nih.gov/books/NBK8262/ |work=Medical Microbiology |editor-last=Baron |editor-first=Samuel |edition=4th |place=Galveston (TX) |publisher=University of Texas Medical Branch at Galveston |isbn=978-0-9631172-1-2 |pmid=21413318 |access-date=2022-06-21|last1=Baron |first1=S. }}</ref> The study of parasites and parasitic diseases is known as [[parasitology]].<ref>{{Cite web |title=Parasitology - Latest research and news {{!}} Nature |url=https://www.nature.com/subjects/parasitology |access-date=2022-06-21 |website=www.nature.com}}</ref> Medical parasitology is concerned with three major groups of parasites: parasitic [[protozoa]], [[helminth]]s, and parasitic [[arthropod]]s.<ref name=":1" /> Parasitic diseases are thus considered those diseases that are caused by [[pathogen]]s belonging [[Taxonomy (biology)|taxonomically]] to either the [[animal]] [[Kingdom (biology)|kingdom]], or the [[protozoa]]n [[Kingdom (biology)|kingdom]].<ref name=":0">{{Cite book |title=Sherris medical microbiology |date=2018-01-12 |others=Ryan, Kenneth J. (Kenneth James), 1940- |isbn=978-1-259-85981-6 |edition=Seventh |location=New York |oclc=1004770160}}</ref>

==Terminology==
Although organisms such as [[bacteria]] function as parasites, the usage of the term "parasitic disease" is usually more restricted. The three main types of organisms causing these conditions are [[protozoa]] (causing [[protozoan infection]]), [[helminths]] ([[helminthiasis]]), and [[ectoparasite]]s.<ref name="urlAbout Parasites | CDC DPD">{{cite web |date=2020-01-28 |title=About Parasites &#124; CDC DPD |url=https://www.cdc.gov/ncidod/dpd/aboutparasites.htm}}</ref> Protozoa and helminths are usually endoparasites (usually living inside the body of the host), while ectoparasites usually live on the surface of the host. Protozoa are single-celled, microscopic organisms that belong to the kingdom [[Protist|Protista]]. Helminths on the other hand are macroscopic, multicellular organisms that belong to the kingdom [[Animals|Animalia]]. Protozoans obtain their required nutrients through pinocytosis and phagocytosis. Helminths of class Cestoidea and Trematoda absorb nutrients, whereas nematodes obtain needed nourishment through ingestion.<ref name=":0" /> Occasionally the definition of "parasitic disease" is restricted to diseases due to endoparasites.<ref name="urlIntestinal Protozoal Diseases: eMedicine Pediatrics: General Medicine">{{cite web |title=Intestinal Protozoal Diseases: eMedicine Pediatrics: General Medicine |url=http://emedicine.medscape.com/article/999282-overview |access-date=2010-04-25}}</ref>

Some parasitic diseases can occur in either an acute or chronic form. The acute form is characterized by quicker and often more severe onset of symptoms. The chronic form is typically less severe but is life-long. Some parasites that cause chronic and acute manifestations in their respective diseases are:

* [[Trypanosoma brucei|Trypanosoma brucei rhodesiense (acute) / Trypanosoma brucei gambiense (chronic)]]
* [[Trypanosoma cruzi]]  
* [[Clonorchis sinensis]]
* [[Paragonimus westermani]]

==Transmission==
{{See also|List of human parasitic diseases}}

=== Infection ===
[[Mammals]] can get parasites from contaminated [[food]] or [[water]], [[bug bites]], [[Animal sexual behaviour|sexual contact]],<ref>{{cite web|url=https://www.medlineplus.gov/parasiticdiseases.html| title=Parasitic Diseases|access-date= 2010-07-07}}</ref> or contact with animals.

Some ways in which people may acquire parasitic infections are walking [[barefeet|barefoot]], inadequate disposal of [[faeces|feces]], lack of [[hygiene]], close contact with someone carrying specific parasites, and eating undercooked foods, unwashed fruits and vegetables or foods from contaminated regions.{{cn|date=June 2021}} It is important to note that only at specific stages in a parasites life is it infectious.<ref>{{Cite web |last=USDA U.S. Department of Agriculture |date=March 28, 2025 |title=Parasites and Foodborne Illness |url=https://www.fsis.usda.gov/food-safety/foodborne-illness-and-disease/illnesses-and-pathogens/parasites-and-foodborne-illness-0 |access-date=April 18, 2025 |website=USDA U.S. Department of Agriculture}}</ref> Contact with non-infective stages will not lead to infection.

Many parasites utilize vectors to infect hosts.<ref>{{Cite web |date=2023-12-06 |title=Vector-borne diseases {{!}} EFSA |url=https://www.efsa.europa.eu/en/topics/topic/vector-borne-diseases#:~:text=A%20vector%20A%20carrier%20of,viruses)%20that%20transmits%20an%20infectious |access-date=2025-04-18 |website=www.efsa.europa.eu |language=en}}</ref> Vectors are vessels for the parasite, and help the parasite infect its next host. Some examples of parasitic diseases that use vectors are [[malaria]], [[Lyme disease]], and [[leishmaniasis]].

==== At-risk groups ====
Many parasitic diseases are concentrated in specific areas of the globe. Majority of these diseases are prevalent along the equator due to the warm temperatures.{{citation needed|date=May 2025}} Therefore, people located in these areas are at greater risk of contracting the disease causing parasites.

Parasitic diseases are far more common among [[marginalized groups]].<ref>{{Cite journal |last1=Hesham Al-Mekhlafi |first1=M. |last2=Surin |first2=Johari |last3=Atiya |first3=A. S. |last4=Ariffin |first4=W. A. |last5=Mohammed Mahdy |first5=A. K. |last6=Che Abdullah |first6=H. |date=2008-08-01 |title=Pattern and predictors of soil-transmitted helminth reinfection among aboriginal schoolchildren in rural Peninsular Malaysia |url=https://www.sciencedirect.com/science/article/abs/pii/S0001706X0800168X |journal=Acta Tropica |volume=107 |issue=2 |pages=200–204 |doi=10.1016/j.actatropica.2008.05.022 |pmid=18582430 |issn=0001-706X|url-access=subscription }}</ref> Lack of indoor bathrooms and access to clean drinking water are only some of the risk factors faced.<ref>{{Cite journal |last1=Karan |first1=Abraar |last2=Chapman |first2=Gretchen B. |last3=Galvani |first3=Alison |date=2012 |title=The influence of poverty and culture on the transmission of parasitic infections in rural nicaraguan villages |journal=Journal of Parasitology Research |volume=2012 |article-number=478292 |doi=10.1155/2012/478292 |doi-access=free |issn=2090-0031 |pmc=3426246 |pmid=22934154}}</ref>  Additionally, in the United States being [[Hispanic]] or [[African Americans|African-American]] have shown to be risk factors for specific parasitic diseases.<ref>{{Cite journal |last=Hotez |first=Peter J. |date=September 2014 |title=Neglected parasitic infections and poverty in the United States |journal=PLOS Neglected Tropical Diseases |volume=8 |issue=9 |article-number=e3012 |doi=10.1371/journal.pntd.0003012 |doi-access=free |issn=1935-2735 |pmc=4154650 |pmid=25188455}}</ref>

== Morbidity ==

=== Symptoms ===
Parasitic diseases can manifest in many different symptoms, with some being [[asymptomatic]]. Many of the symptoms of parasitic diseases are common among other ailments, such as [[Foodborne illness|food poisoning]] or the [[Influenza|flu]]. This can cause correct diagnoses to take a while. The target [[Organ (biology)|organ(s)]] of the parasite typically dictates the symptoms experienced:

==== General<ref>{{Cite web |date=2025-04-01 |title=Parasitic Infection: Causes, Symptoms & Treatment |url=https://my.clevelandclinic.org/health/diseases/24885-parasitic-infection |access-date=2025-04-18 |archive-url=https://web.archive.org/web/20250401131223/https://my.clevelandclinic.org/health/diseases/24885-parasitic-infection |archive-date=1 April 2025 }}</ref> ====

* Fever
* Ulcers/lesions
* Death
* Headache
* [[Malaise]]
* Anemia
* Muscle Pain

==== Gastrointestinal Tract<ref>{{Cite web |title=Intestinal parasites Information {{!}} Mount Sinai - New York |url=https://www.mountsinai.org/health-library/condition/intestinal-parasites |access-date=2025-04-18 |website=Mount Sinai Health System |language=en-US}}</ref> ====

* [[Dysentery]]
* Constipation
* Abdominal pain
* Vomiting
* Nausea
* Bloating
* Anorexia

==== Lungs<ref>{{Cite web |date=2024-06-06 |title=CDC - DPDx - Paragonimiasis |url=https://www.cdc.gov/dpdx/paragonimiasis/index.html |access-date=2025-04-18 |website=www.cdc.gov |language=en-us}}</ref> ====

* Cough
* Blood in sputum
* Lesions

==== Skin<ref>{{Cite web |last=CDC |date=2024-05-08 |title=Clinical Features of Zoonotic Hookworm |url=https://www.cdc.gov/zoonotic-hookworm/hcp/clinical-features/index.html |access-date=2025-04-18 |website=Zoonotic Hookworm |language=en-us}}</ref> ====

* Local inflammation
* Local dermatitis
* Hives
* Itching
* Rash

==Treatment==

=== Diagnosis ===
Different parasitic diseases require different [[Diagnostic method|diagnostic methods]] because different parasites have different diagnostic stages. Testing routes will often be determined by symptoms.

==== Testing<ref>{{Cite web |last=CDC |date=2024-12-17 |title=Diagnosis of Parasitic Diseases |url=https://www.cdc.gov/parasites/testing-diagnosis/index.html |access-date=2025-04-18 |website=Parasites |language=en-us}}</ref> ====

* [[Stool test|Stool Test]]
* [[Blood test|Blood Test]]
* [[Colonoscopy]]/[[Endoscopy]]
* [[Radiography|X-ray]]/[[Magnetic resonance imaging|MRI]]/ [[CT scan|CT Scan]]

=== Therapies ===
Parasitic infections can usually be treated with [[antiparasitic]] [[drugs]].{{Citation needed|date=June 2022}} [[Phage therapy|The use of viruses to treat infections]] caused by [[protozoa]] has been proposed.<ref>{{Cite journal | last1 = Keen | first1 = E. C. | title = Beyond phage therapy: Virotherapy of protozoal diseases | doi = 10.2217/FMB.13.48 | journal = Future Microbiology | volume = 8 | issue = 7 | pages = 821–823 | year = 2013 | pmid =  23841627}}</ref><ref>{{Cite journal | last1 = Hyman | first1 = P. | last2 = Atterbury | first2 = R. | last3 = Barrow | first3 = P. | doi = 10.1016/j.tim.2013.02.006 | title = Fleas and smaller fleas: Virotherapy for parasite infections | journal = Trends in Microbiology | volume = 21 | issue = 5 | pages = 215–220 | year = 2013 | pmid =  23540830| url = https://eprints.nottingham.ac.uk/45247/ }}</ref>

==See also==
* [[Protozoan infection]]
* [[Babesiosis]]
* [[Giardiasis]]

==References==
{{Reflist}}

==External links==
{{Medical resources
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|   MeshID         = D010272
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{{Amoebozoa diseases}}
{{Excavata diseases}}
{{Chromalveolate diseases}}
{{Helminthiases}}
{{Pediculosis, acariasis and other infestations}}
{{Disease groups}}
{{Authority control}}
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[[Category:Parasitic diseases| ]]