List of parasites of humans

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Main article: Human parasites


Protozoan organisms[edit]

Common name of organism or disease Latin name (sorted) Body parts affected Diagnostic specimen Prevalence Source/ Transmission (Reservoir/ Vector)
Granulomatous amoebic encephalitis and Acanthamoeba keratitis (eye infection) Acanthamoeba spp. eye, brain, skin culture worldwide contact lenses cleaned with tap water
Granulomatous amoebic encephalitis (skin infection) Balamuthia mandrillaris brain, skin culture worldwide via respiratory tract or skin lesion
Babesiosis Babesia B. divergens, B. bigemina, B. equi, B. microfti, B. duncani red blood cells Giemsa-stained thin blood smear New York, Martha's Vineyard, Nantucket (different species have worldwide distribution) tick bites, e.g. Ixodes scapularis
Balantidiasis Balantidium coli intestinal mucosa, may become invasive in some patients stool (diarrhea=ciliated trophozoite; solid stool=large cyst with horseshoe shaped nucleus) ingestion of cyst, zoonotic infection acquired from pigs (feces)
Blastocystosis Blastocystis spp. intestinal direct microscopy of stool (PCR, anti body)  • worldwide: one of the most common human parasites[1][2]
 • United States: infected ~23% of the population during year 2000[1][3]
 • Developing regions: infects 40–100% of the total populations[1][2][4]
eating food contaminated with feces from an infected human or animal
Cryptosporidiosis Cryptosporidium spp. intestines stool widespread ingestion of oocyst (sporulated), some species are zoonotic (e.g. bovine fecal contamination)
Cyclosporiasis Cyclospora cayetanensis intestines stool United States ingestion of oocyst thru contaminated food
Dientamoebiasis Dientamoeba fragilis intestines stool up to 10% in industrialized countries ingesting water or food contaminated with feces
Amoebiasis Entamoeba histolytica Intestines (mainly Large, can go to extraintestinal sites) stool (fresh diarrheic stools have amoeba, solid stool has cyst) areas with poor sanitation, high population density and tropical regions fecal-oral transmission of cyst, not amoeba
Giardiasis Giardia lamblia lumen of the small intestine stool widespread ingestion of cysts in fecal contaminated water or food, can be zoonotic (deer, beavers)
Isosporiasis Isospora belli epithelial cells of small intestines stool worldwide - less common than Toxoplasma or Cryptosporidium fecal oral route - ingestion of sporulated oocyst
Leishmaniasis Leishmania spp. cutaneous, mucocutaneous, or visceral visual identification of lesion or microscopic stain with Leishman's or Giemsa's stain Visceral leishmaniasis- Worldwide; Cutaneous leishmaniasis - Old World; Mucocutaneous leishmaniasis - New World Phlebotomus Lutzomyia- bite of several species of phlebotomine sandflies
Primary amoebic meningoencephalitis (PAM)[5][6] Naegleria fowleri brain culture rare but deadly Nasal insufflation of contaminated warm fresh water, poorly chlorinated swimming pools, hot springs, soil
Malaria Plasmodium falciparum (80% of cases), Plasmodium vivax, Plasmodium ovale curtisi, Plasmodium ovale wallikeri, Plasmodium malariae, Plasmodium knowlesi red blood cells, liver Blood film tropical - 250 million cases/year Anopheles mosquito, bites at night
Rhinosporidiosis Rhinosporidium seeberi nose, nasopharynx biopsy India and Sri Lanka nasal mucosa came into contact with infected material through bathing in common ponds
Sarcocystosis Sarcocystis bovihominis,Sarcocystis suihominis intestine, muscle muscle biopsy widespread ingestion of uncooked/undercooked beef/pork with Sarcocystis sarcocysts
Toxoplasmosis (Acute and Latent) Toxoplasma gondii eyes, brain, heart, liver blood and PCR worldwide: one of the most common human parasites; estimated to infect between 30–50% of the global population.[7][8] ingestion of uncooked/undercooked pork/lamb/goat with Toxoplasma bradyzoites, ingestion of raw milk with Toxoplasma tachyzoites, ingestion of contaminated water food or soil with oocysts in cat feces that is more than one day old
Trichomoniasis Trichomonas vaginalis female urogenital tract (males asymptomatic) microscopic examination of genital swab 7.4 million Americans sexually transmitted infection - only trophozoite form (no cyst)
Sleeping sickness Trypanosoma brucei blood lymph and central nervous systems microscopic examination of chancre fluid, lymph node aspirates, blood, bone marrow 50,000 to 70,000 people tsetse fly, day biting fly of the genus Glossina
Chagas disease Trypanosoma cruzi colon, esophagus, heart, nerves, muscle and blood Giemsa stain - blood Mexico, Central America, South America - 16-18 million Triatoma/Reduviidae - "Kissing bug" Insect Vector, feeds at night

Helminths organisms (worms)[edit]

Helminth organisms (also called helminths or intestinal worms) include:


Common name of organism or disease Latin name (sorted) Body parts affected Diagnostic specimen Prevalence Transmission/Vector
Tapeworm - Tapeworm infection Cestoda, Taenia multiceps intestine stool rare
Diphyllobothriasis - tapeworm Diphyllobothrium latum intestines, blood stool (microscope) Europe, Japan, Uganda, Peru, Chile ingestion of raw fresh water fish
Echinococcosis - tapeworm Echinococcus granulosus, Echinococcus multilocularis, E. vogeli, E. oligarthrus liver, lungs, kidney, spleen imaging of hydatid cysts in the liver, lungs, kidney and spleen Mediterranean countries as intermediate host, ingestion of material contaminated by feces from a carnivore; as definite host, ingestion of uncooked meat (offal) from a herbivore
Hymenolepiasis[9] Hymenolepis nana, Hymenolepis diminuta ingestion of material contaminated by flour beetles, meal worms, cockroaches
Beef tapeworm Taenia saginata Intestines stool worldwide distribution ingestion of undercooked beef
Cysticercosis-Pork tapeworm Taenia solium Brain, muscle, Eye (Cysts in conjuntiva/anterior chamber/sub-retinal space) stool, blood Asia, Africa, South America, Southern Europe, North America. ingestion of undercooked pork
Bertielliasis Bertiella mucronata, Bertiella studeri Intestines Stool Rare Contact with non human primates
Sparganosis Spirometra erinaceieuropaei ingestion of material contaminated with infected dog or cat faeces (humans: dead-end host)


Clonorchiasis Clonorchis sinensis; Clonorchis viverrini gall bladder ducts and inflammation of liver ingestion of under prepared fresh water fish
Lancet liver fluke Dicrocoelium dendriticum gall bladder rare ingestion of ants
Liver fluke - Fasciolosis[10] Fasciola hepatica, Fasciola gigantica liver, gall bladder stool Fasciola hepatica in Europe, Africa, Australia, the Americas and Oceania; Fasciola gigantica only in Africa and Asia, 2.4 million people infected by both species freshwater snails
Fasciolopsiasis - intestinal fluke[11] Fasciolopsis buski intestines stool or vomitus (microscope) East Asia - 10 million people ingestion of infested water plants or water (intermediate host:amphibic snails)
Gnathostomiasis[12] Gnathostoma spinigerum, Gnathostoma hispidum subcutaneous tissues (under the skin) physical examination rare - Southeast Asia ingestion of raw or undercooked meat (e.g., freshwater fish, chicken, snails, frogs, pigs) or contaminated water
Metagonimiasis - intestinal fluke Metagonimus yokogawai stool Siberia, Manchuria, Balkan states, Israel, Spain ingestion of undercooked or salted fish
Metorchiasis Metorchis conjunctus Canada, USA, Greenland ingestion of raw fish
Chinese Liver Fluke Opisthorchis viverrini, Opisthorchis felineus, Clonorchis sinensis bile duct 1.5 million people in Russia consuming infected raw, slightly salted or frozen fish
Paragonimiasis, Lung Fluke Paragonimus westermani; Paragonimus africanus; Paragonimus caliensis; Paragonimus kellicotti; Paragonimus skrjabini; Paragonimus uterobilateralis lungs sputum, feces East Asia ingestion of raw or undercooked freshwater crabs crayfishes or other crustaceans
Schistosomiasis - bilharzia, bilharziosis or snail fever (all types) Schistosoma sp. Africa, Caribbean, eastern South America, east Asia, Middle East - 200 million people skin exposure to water contaminated with infected fresh water snails
intestinal schistosomiasis Schistosoma mansoni and Schistosoma intercalatum intestine, liver, spleen, lungs, skin,rarely infects the brain stool Africa, Caribbean, South America, Asia, Middle East - 83 million people skin exposure to water contaminated with infected Biomphalaria fresh water snails
urinary schistosomiasis Schistosoma haematobium kidney, bladder, ureters, lungs, skin urine Africa, Middle East skin exposure to water contaminated with infected Bulinus sp. snails
Schistosomiasis by Schistosoma japonicum Schistosoma japonicum intestine, liver, spleen, lungs, skin stool China, East Asia, Philippines skin exposure to water contaminated with infected Oncomelania sp. snails
Asian intestinal schistosomiasis Schistosoma mekongi - South East Asia skin exposure to water contaminated with infected Neotricula aperta - fresh water snails
Echinostoma echinatum small intestine Far East ingestion of raw fish, mollusks, snails
Swimmer's itch Trichobilharzia regenti, Schistosomatidae skin exposure to contaminated water (snails and vertebrates)


Ancylostomiasis/Hookworm Ancylostoma duodenale, Necator americanus lungs, small intestine, blood stool common in tropical, warm, moist climates penetration of skin by L3 larva
Angiostrongyliasis Angiostrongylus costaricensis intestine stool ingestion of infected faeces or infected slugs
Anisakiasis[13] Anisakis allergic reaction biopsy incidental host ingestion of raw fish, squid, cuttlefish, octopus
Roundworm - Parasitic pneumonia Ascaris sp. Ascaris lumbricoides Intestines, liver, appendix, pancreas, lungs, Löffler's syndrome stool common in tropical and subtropical regions
Roundworm - Baylisascariasis Baylisascaris procyonis Intestines, liver, lungs, brain, eye rare: North America stool from raccoons
Roundworm-lymphatic filariasis Brugia malayi, Brugia timori lymph nodes blood samples tropical regions of Asia Arthropods
Dioctophyme renalis infection Dioctophyme renale kidneys (typically the right) Urine Rare Ingestion of undercooked or raw freshwater fish
Guinea worm - Dracunculiasis Dracunculus medinensis subcutaneous tissues, muscle skin blister/ulcer South Sudan (eradication ongoing)
Pinworm - Enterobiasis Enterobius vermicularis, Enterobius gregorii intestines, anus stool; tape test around anus widespread; temperate regions
Halicephalobiasis Halicephalobus gingivalis brain soil contaminated wounds
Loa loa filariasis, Calabar swellings Loa loa filaria Connective tissue, lungs, eye blood (Giemsa, haematoxylin, eosin stain) rain forest of West Africa - 12-13 million people Tabanidae - horse fly, bites in the day
Mansonelliasis, Filariasis Mansonella streptocerca subcutaneous layer of skin insect
River blindness, Onchocerciasis Onchocerca volvulus skin, eye, tissue bloodless skin snip Africa, Yemen, Central and South America near cool, fast flowing rivers Simulium/Black fly, bite during the day
Strongyloidiasis - Parasitic pneumonia Strongyloides stercoralis Intestines, lungs, skin (Larva currens) stool, blood skin penetration
Thelaziasis Thelazia californiensis, Thelazia callipaeda Eyes ocular examination Asia, Europe Amiota (Phortica) variegata, Phortica okadai
Toxocariasis Toxocara canis, Toxocara cati liver, brain, eyes (Toxocara canis - Visceral larva migrans, Ocular larva migrans) blood, ocular examination worldwide distribution pica, unwashed food contamined with Toxocara eggs, undercooked livers of chicken
Trichinosis Trichinella spiralis, Trichinella britovi, Trichinella nelsoni, Trichinella nativa muscle, periorbital region, small intestine blood more common in developing countries due to improved feeding practices in developed countries. ingestion of undercooked pork
Whipworm Trichuris trichiura, Trichuris vulpis large intestine, anus stool (eggs) common worldwide accidental ingestion of eggs in dry goods such as beans, rice, and various grains or soil contaminated with human feces
ElephantiasisLymphatic filariasis Wuchereria bancrofti lymphatic system thick blood smears stained with hematoxylin. Tropical and subtropical mosquito, bites at night

Other organisms[edit]

Acanthocephaliasis Archiacanthocephala, Moniliformis moniliformis Gastrointestinal tract, peritoneum, eye Faeces, parasite itself worldwide ingestion of intermediate hosts
Halzoun Syndrome Linguatula serrata nasopharynx physical examination Mid East ingestion of raw or undercooked lymph nodes (e.g., meat from infected camels and buffalos)
Myiasis Oestroidea, Calliphoridae, Sarcophagidae dead or living tissue
Screwworm, Cochliomyia Cochliomyia hominivorax (family Calliphoridae) skin and wounds visual North America (eradicated), Central America, North Africa direct contact with fly
Chigoe flea Tunga penetrans Subcutaneous tissue physical examination Central and South America
Bedbug Cimicidae: Cimex lectularius skin visual Worldwide sharing of clothing and bedding
Human Botfly Dermatobia hominis Subcutaneous tissue physical examination Central and South America Mosquitoes and biting flies


Head louse - Pediculosis Pediculus humanus hair follicles visual identification under magnification Common worldwide head-to-head contact
Body louse - Pediculosis Pediculus humanus corporis visual identification under magnification (Vagabond's disease) Worldwide skin-to-skin contact such as sexual activity and via sharing clothing or bedding
Crab louse - Pediculosis Pthirus pubis pubic area, eyelashes visual identification under magnification Worldwide skin-to-skin contact such as sexual activity and via sharing clothing or bedding
Demodex - Demodicosis Demodex folliculorum/brevis/canis eyebrow, eyelashes Microscopy of eyelash or eyebrow hair follicle Pandemic, worldwide prolonged skin-to-skin contact
Scabies Sarcoptes scabiei skin microscopy of surface scrapings Worldwide skin-to-skin contact such as sexual activity and via sharing clothing or bedding
"Chiggers" (Trombiculidae) - Trombiculosis Arachnida: Trombiculidae skin visual identification under magnification, microscopy worldwide (mesic habitats) High grass, weeds
Flea, Siphonaptera Pulex irritans skin visual identification under magnification Worldwide environment
Tick Arachnida: Ixodidae and Argasidae skin visual Worldwide High grass, leaf litter, weeds


  1. ^ a b c Boorom KF, Smith H, Nimri L, Viscogliosi E, Spanakos G, Parkar U, Li LH, Zhou XN, Ok UZ, Leelayoova S, Jones MS (2008). "Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection". Parasit Vectors. 1 (1): 40. doi:10.1186/1756-3305-1-40. PMC 2627840free to read. PMID 18937874. Blastocystis is now by far the most prevalent mono-infection in symptomatic patients in the United States [14] and was found 28.5 times more often than Giardia lamblia as a mono-infection in symptomatic patients in a 2000 study [14].
    Figure 4: Prevalence of IBS and Blastocystosis by country
  2. ^ a b Roberts T, Stark D, Harkness J, Ellis J (May 2014). "Update on the pathogenic potential and treatment options for Blastocystis sp". Gut Pathog. 6: 17. doi:10.1186/1757-4749-6-17. PMC 4039988free to read. PMID 24883113. Blastocystis is one of the most common intestinal protists of humans. ... A recent study showed that 100% of people from low socio-economic villages in Senegal were infected with Blastocystis sp. suggesting that transmission was increased due to poor hygiene sanitation, close contact with domestic animals and livestock, and water supply directly from well and river [10]. ...
    Table 2: Summary of treatments and efficacy for Blastocystis infection
  3. ^ Amin OM (2002). "Seasonal prevalence of intestinal parasites in the United States during 2000" (PDF). Am. J. Trop. Med. Hyg. 66 (6): 799–803. PMID 12224595. Retrieved 3 January 2016. Parasitologic investigations of large patient populations are rarely conducted in the United States, where the illusion of freedom from parasitic infections still predominates. Such investigations are considerably more common in third-world countries where endemic parasitoses are more readily documented.1 In an attempt to address this problem we reported the results of routine examination of fecal specimens for parasites from 644 patients in the United States during the summer of 1996. ...
    Prevalence. Nine hundred sixteen (32%) of 2,896 tested patients were infected with 18 species of intestinal parasites in the year 2000 (Table 1) in 48 states and the District of Columbia as follows ... Blastocystis hominis was the most frequently detected parasite in single and multiple infections, with Cryptosporidium parvum and Entamoeba histolytica/E. dispar ranking second and third, respectively.
  4. ^ El Safadi D, Gaayeb L, Meloni D, Cian A, Poirier P, Wawrzyniak I, Delbac F, Dabboussi F, Delhaes L, Seck M, Hamze M, Riveau G, Viscogliosi E (March 2014). "Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide". BMC Infect. Dis. 14: 164. doi:10.1186/1471-2334-14-164. PMC 3987649free to read. PMID 24666632. 
  5. ^ Cogo PE, Scaglia M, Gatti S, Rossetti F, Alaggio R, Laverda AM, et al. Fatal Naegleria fowleri Meningoencephalitis, Italy Emerging Infectious Diseases [serial on the Internet]. 2004 Oct; accessed Jan 2009
  6. ^ Bennett, Nicholas John State University of New York Upstate Medical University Domachowske, Joseph; Khan, Asad A Louisiana State University Health Science Center; King, John W; Cross, J Thomas Naegleria eMedicine; accessed Jan 2009
  7. ^ Flegr J, Prandota J, Sovičková M, Israili ZH (March 2014). "Toxoplasmosis--a global threat. Correlation of latent toxoplasmosis with specific disease burden in a set of 88 countries". PLoS ONE. 9 (3): e90203. doi:10.1371/journal.pone.0090203. PMC 3963851free to read. PMID 24662942. Toxoplasmosis is becoming a global health hazard as it infects 30-50% of the world human population. Clinically, the life-long presence of the parasite in tissues of a majority of infected individuals is usually considered asymptomatic. However, a number of studies show that this 'asymptomatic infection' may also lead to development of other human pathologies. ... The seroprevalence of toxoplasmosis correlated with various disease burden. Statistical associations does not necessarily mean causality. The precautionary principle suggests however that possible role of toxoplasmosis as a triggering factor responsible for development of several clinical entities deserves much more attention and financial support both in everyday medical practice and future clinical research. 
  8. ^ Pappas, G; Roussos, N; Falagas, ME (October 2009). "Toxoplasmosis snapshots: global status of Toxoplasma gondii seroprevalence and implications for pregnancy and congenital toxoplasmosis.". International Journal for Parasitology. 39 (12): 1385–94. doi:10.1016/j.ijpara.2009.04.003. PMID 19433092. 
  9. ^ Tolan, Robert W Jr Hymenolepiasis eMedicine; updated Feb 2008
  10. ^ Yılmaza, Hasan; Gödekmerdan, Ahmet Human fasciolosis in Van province, Turkey doi:10.1016/j.actatropica.2004.04.009
  11. ^ Centers for Disease Control and Prevention Fasciolopsiasis
  12. ^ Tolan, Robert W Gnathostomiasis eMedicine, updated Feb 2008
  13. ^ Anisakiasis