Intestinal Parasites

Unicellular Parasites (Protozoa)

PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSYMPTOMS and SIGNS
Balantidium coli, balantidiasisworldwide/ruralcontact with pigs, infected watersevere diarrhea
Blastocystis hominis, blastocystosisworldwidestool to mouthnone or mild diarrhea
Cryptosporidium, cyptosporidiosis (crypto)worldwidestool to mouth, contaminated waterdiarrhea
Cyclospora cayetanensis, cyclosporiasishot climatescontaminated water/fooddiarrhea
Entamoeba histolytica, amebiasistropical/ruralstool to mouthdiarrhea, rarely systemic infection
Giardia lamblia, giardiasisworldwidestool to mouthdiarrhea
Isospora belli, coccidiosisworldwidedog/cat puppies feces; persons with low immunitydiarrhea
Microsporidia, microsporidiosisworldwideingestion, inhalation, person to person contact, persons with low-immunity (AIDS)chronic diarrhea, gallbladder infection, eye irritation


More about intestinal parasites: pictures, symptoms, diagnosis, treatment 

Intestinal Worms

 PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSYMPTOMS and SIGNS
ROUNDWORMS (Nematoda):   
Anisaxis simplex; 1 inch; anisakiasisworldwide, Japanundercooked saltwater fish, sushivomiting, diarrhea, diagnosis with upper endoscopy
Ascaris lumbricoides; up to 12 inches; ascariasiswarm climates, south/rural USstool-to-mouth, contaminated foodworms in the stool, abdominal pain or cough
Hookworms: Ancylostoma duodenale, Necator americanus; 1/2 inchwarm climateswalking barefoot, swallowing soilskin rash on the foot, diarrhea or cough
Enterobius vermicularis, pinworm, seatworm, threadworm; 1/2 inch; enterobiasisworldwidestool-to-mouthanal itch
Strongyloides stercoralis; threadworm; 2 mm; strongyloidiasiswarm climates, south USwalking barefootfoot itch, mild diarrhea, cough
Trichinella spiralis; 1-3 mm; trichinellosis (trichinosis)worldwide/ruralnon-commercial porkdiarrhea, headache, muscle pains, chills, eye swelling
Whipworms: Trichuris trichiura; 2mm; trichuriasisworldwide/warm climates, south US/ruralstool-to-mouth, ingesting dry beansdiarrhea
TAPEWORMS (Cestoda):   
Diphyllobothrium latum, fish tapeworm, 10 metersNorth hemisphereraw fishdiarrhea
Dipylidium caninum, dog tapeworm, 20 inchesworldwideingesting dog/cat fleas, childrendiarrhea
Hymenolepis nana, dwarf tapeworm; 1-2 inchesworldwide, temperate climatesstool-to-mouthdiarrhea, itchy bottom
Taenia saginata, beef tapeworm; several metersworldwideraw/undercooked beefnausea, irritation of anus, crawling segments in stool
Taenia solium, pork tapeworm; several meters, cysticercosisworldwide/ruralundercooked pork meat, stool-to-mouthdiarrhea

More about intestinal worms: pictures, symptoms, diagnosis, treatment 

Intestinal Flukes or FLATWORMS (Trematoda)

 PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSYMPTOMS and SIGNS
Fasciolopsis buski; 1-3 inchesChina, south Asiaingesting water plants infected by pig stooldiarrhea, abdominal pain
Metagonimus yokogawai; 1/2 mmSiberia, Balkan, Spainundercooked freshwater fishdiarrhea, abdominal pain
ParagonimusAfrica, south Asia, South Americaraw crustaceansdiarrhea, cough
Schistosoma haematobium, S. japonicum, and S. mansoni, bilharziaAfrica, South America, Middle East, south Asia; not in USswimming in freshwateritchy rash, after 1-2 months: fever, cough; years: blood in urine (parasites live in veins around bladder and intestine)

Liver Parasites

 PARASITE / DISEASEDISTRIBUTION TRANSMISSIONSYMPTOMS and SIGNS
FLUKES or FLATWORMS(Trematoda):   
Clonorchis sinensis and Opisthorchis viverrini, Chinese liver fluke; 2-25 mmeast Asiaundercooked fishlives in bile duct, RUQ abdominal cramps, jaundice
Fasciola hepatica, sheep liver flukeEurope, Middle East, Asiaraw watercress in sheep/cattle raising areaslives in bile duct, fever, abdominal pain
TAPEWORMS (Cestoda):   
Echinococcus multilocularis, hydatid diseaseEurope, North America, Asiastool-to-mouth, feces of cats, foxes, coyotesliver cysts, weight loss, RUQ abdominal pain

Skin Parasites

 PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSYMPTOMS and SIGNS
Bedbug, red, flat, non-flying insect; 5-7 mmworldwidebedlining, clothesitchy rash, few bumps in a row
Bot fly (human), Dermatobia hominisCentral and South Americamosqitoes transmit bot fly eggspainful, raised oozing bumps with a larva underneath
LICE:   
Body louse, Pediculus humanus corpori, 3mmworldwideclothesitchy red bite marks
Head louse, Pediculus humanus capitis, white/gray, 2-3 mmworldwideperson-to-personitchy scalp, lice attached to hair
Pubic (crab) louse, Phthirus pubis; 2mmworldwideskin-to-skin or sexual contactitchy pubic area
MITES:   
Chiggers, harvest mites, red bugs, 1mmworldwidewalking in grassitchy red bumps on legs
Demodex folliculorum, face mites; 0,1-0,4 mmworldwidelive in scalp/facial hair follicles in most peopleitchy scalp, eyebrows, acne rosacea, hair loss
Dust mitesworldwidehouse dustitchy rash
Scabies mites, Sarcoptes scabieiworldwideskin-to-skin contactitchy rash
FLEAS: cat (Xenopsylla cheopis), human (Pulex irritans), dog, rat, black, 1-4 mmworldwidecontact with petsthree itchy bumps in a row
TICKS, several species, 3-10 mmworldwidewalking in woodsblood sucking tick firmly attached to skin
Cutaneus larva migrans (CLM), roudwormwarm climateswalking barefootground itch, creeping eruption
OTHER:   
Dracunculus medinensis, roundworm; 80 cm, Guinea worm diseasewest Africadrinking contaminated stagnant waterpainful skin ulcers
Leishmania, unicellular parasite, cutaneus leishmaniasis, Balkan sore, Delhi boilwarm climates, south/rural USsandfly biteskin boils
Loa loa filaria, roundworm, loiasisWest AfricaDeer flyred skin (Calabar) swelling, eye pain
Onchocerca volvulus, roundworm (filaria), onchocerciasis, river blindnessAfrica, Central America, near riversblackfly biteitchy skin nodules, de/pigmentations, enlarged lymph nodes
Swimmer’s itch, cercarial dermatitis, caused by various parasitesworldwidefresh or marine coastal wateritchy red bumps

More about dust and skin mites and itchy skin in general

Blood Parasites

 PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSYMPTOMS and SIGNS
Babesia, babesiosisUS (north/mid)ticksred cells, flu-like symptoms, jaundice
Plasmodium, malariasouth Asia, sub-saharian Africamosquito bitehigh fever, shaking chills
Schistosoma haematobium, S. japonicum, and S. mansoni, bloof flukes, bilharziaAfrica, South America, Middle East, south Asia; not in USswimming in freshwateritchy rash, after 1-2 months: fever, cough; years: blood in urine (parasites live in veins around bladder and intestine)
Trypanosoma brucei, African sleeping sicknessAfricatsetse flyfever, headaches, joint pains, itching, drowsiness

Lymph Parasites

 PARASITE / DISEASEDISTRIBUTION TRANSMISSIONSYMPTOMS and SIGNS
Wuchereria bancrofti, microscopic roundworm, lymphatic filariasis (elephantiasis)tropics, NOT in USmosquito biteswollen leg, scrotum, arm, breast, skin rash, blindness
Onchocerca volvulus, onchocerciasis (river blindness)Africa, Central Americablackfly biteenlarged lymph nodes in groin, skin nodules

Parasites in Internal Organs

 PARASITE / DISEASEDISTRIBUTIONTRANSMISSIONSIGNS and SYMPTOMS
BRAIN:   
Taenia solium, pork tapeworm, cysticercosisworldwide/ruralundercooked pork meat, stool-to-mouthneurocysticercosis with headache, seizures, eyes
Echinococcus granulosus and multilocularis, tapeworm; hydatid diseaseMediterran, Middle East, South America, Iceland, Australia, New Zealand, southern parts of Africadog fecesseizures, other neurological symptoms
EYE:   
Acanthamoeba, unicellularworldwideswimming with contact lenses in pools or freshwatereye irritation (keratitis); granulomatose amebic encephalitis (GAE): seizures, hemiparesis
Onchocerca volvulus, roundworm (filaria), onchocerciasis, river blindnessAfrica, Central Americablackfly biteitchy skin nodules, de/pigmentations, enlarged lymph nodes, blindness (keratitis)
Microsporidiaworldwideingestion, inhalation, person-to-person contact, persons with low-immunity (AIDS)eye (cornea) irritation
KIDNEY:   
Dioctophyme renale, giant kidney worm (roundworm); up to 40 cmworldwideundercooked/raw freshwater fish or frogsenlarged, painful kidney on one side, blood in urine
LUNGS:   
Paragonimus westermani, lung fluke, 1cmN and S America, Africa, southeast Asiaraw/undercooked seafoodcoughing up blood
Pneumocystis jirovecii (previously P. caninii) is now classified as fungus, pneumoniaworldwidesneezing, coughing; in persons with low immunity (AIDS)fever, night sweats, dry cough, weight loss
NOSE:   
Rhinosporidium seeberi, rhinosporidiosissouth India, Africa, south US, South Americaworking or bathing in standing water (lakes)blocked nose on one side, nosebleeds, polyps in the nose
VAGINA:   
Trichomonas vaginalis, trichomoniasisworldwidesexually transmittedvaginal discharge
VARIOUS ORGANS:   
Baylisascaris, racoon roundwormnorth/mid USsoil/water, huntersnausea, tiredness, liver enlargement, loss of coordination, lack of attention, blindness, coma
Echinococcus granulosus and multilocularis, tapeworm; hydatid diseaseMediterran, Middle East, South America, Iceland, Australia, New Zealand, southern parts of Africadog fecesjaundice, abdominal presure, low-grade fever, cough…due to cysts (1-15 inches) in liver, lungs, muscles, kidneys..
Leishmania, unicellular parasite, visceral leishmaniasis, Kala azarsub/tropics, south Europesandfly bitefever, enlarged liver/spleen, dark skin
Schistosoma haematobium, S. japonicum, and S. mansoni, bloof flukes, schistosomiasis, bilharziaAfrica, South America, Middle East, south Asia; not in USswimming in freshwateritchy rash, after 1-2 months: fever, cough; years: blood in urine, bloody diarrhea (parasites in bladder/intestine veins)
Taenia solium, pork tapeworm, cysticercosisworldwide/ruralundercooked pork meat, stool-to-mouthneurocysticercosis with headache, seizures, eyes
Toxocara canis, T. cati, roundworm, visceral and ocular larva migransworldwidedog/cat puppies stoolfever, coughing, blindness
Toxoplasma gondii, unicellular parasite, toxoplasmosisworldwidecat feces, contaminated meat, mother-to-childmiscariage, swollen glands, bluured vision, eye pain, headache, lungs, liver
Trichinella spiralis, roundworm, trichinellosis or trichinosisworldwide/ruralnoncommercial pork meatdiarrhea, headache, muscle pains, chills, eye swelling
Trypanosoma cruzi, American trypanosomiasis or Chagas diseaseCentral and South Americatriatomine bug bite, contaminated foodfever, malaise, red skin swelling, swollen eye, digestive problems, enlarged nodes, liver/spleen, rapid heartbeat

Related Articles:

References:

  1. Parasitic diseases: transmission, symptoms, pictures, treatment (cdc.gov)

Article reviewed by Dr. Greg. Last updated on August 3, 2013