Concise review of Lumen-dwelling Parasites Mark K. Huntington, MD PhD FAAFP Sioux Falls Family Medicine Residency Program - Sanford School of Medicine of the University of South Dakota

NOTICE:  As presented at AAFP-CIHI 2009, this lecture was amply illustrated with many images – some of whose position in the public domain is not clear. To comply with potential copyright issues, all images have been removed from this online version. Sorry (you should have been here!).  MKH - 12 Sept 2009

A Two-Part series:  Lumen-dwelling parasites  Tissue-dwelling parasites

Supplemental resources  Despommier’s Parasitic Diseases  Markell & Voge’s Medical Parasitology  Ash et al’s Parasites: A Guide to Laboratory Procedures & Identification 

PG PRETTY GRUESOME These lectures are amply illustrated with pictures designed to make even calloused surgeons squirm.

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Nematodes

Roundworms  Ascaris  Enterobius  Hookworms (Necator, Ancylostoma)  Trichuris  Anisakiasis (Anisakis, Phocanema)  Strongyloides

Ascariasis

Prototype geohelminth

Ascaris  Main Symptoms: asthma, biliary or colon obstruction  After ingestion, larvae hatch and migrate to the liver, then heart, then lungs, and finally the GI tract.

Trichuriasis (whipworm)

Trichuriasis  Main symptoms:  diarrhea,  tenesmus,  weight loss,  Rarely, rectal prolapse

Hookworms

Hookworms  Main symptoms:  Anemia  Ground itch  Prevention: shoes!

Strongyloidiasis

Strongyloidiasis  Main symptoms:  Diarrhea  Polymicrobial sepsis  Found as larvae, not ova, in stool

Enterobiasis (pinworms)

Enterobiasis  Main symptoms: pruritis ani  Diagnosed via Scotch TM Tape Test

Anisakiasis

Anasakiasis  Main symptoms:  Transient GI upset  Eosinophilic granulomas (often misdiagnosed)

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Flatworms  Tapeworms (cestodes)  Flukes (trematodes)

Tapeworms

Cestodes  Diphyllobothrium  Dipylidium  Hymenolepsis  Taenia  Echinococcus

Prototype cestode TTTTwo hosts, two stages

Cestodes  Main symptoms:  Diarrhea / malabsorption  Proglottid escape  (Tissue-dwelling phase symptoms are worse)

Cestodes  Diphyllobothrium (fish, B12 deficiency)  Dipylidium (dog)  Hymenolepsi s (rodent/arthropod)  Taenia (beef/pork, cysticercosis)  Echinococcus (dog, hydatid disease)

Flukes

Trematodes  Liver flukes  Bile flukes  Schistosomes

Prototype trematode

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Categories of Lumen Parasites  Roundworms  Flatworms  Protozoa

Protozoa  Amoebae  Flagellates  Others

Amoebae  Entamoeba histolytica – the main pathogenic amoebae  E. coli – appearance is similar to E. histolytica  Others  Iodamoeba butschlii  Endolimax nana  (Naegleria covered in Tissue Parasites lecture)

Flagellates  Giardia lamblia  Trichomonas  T. hominis – GI parasite  T. vaginalis – GU parasite

Giardiasis

Giardiasis  Main symptom: malabsorptive diarrhea

Trichomoniasis

Trichomoniasis  Main symptoms:  Discomfort  Discharge

Miscellaneous Protozoa  Cryptosporidium – sporozoan  Balantidium - ciliate

Cryptosporidiosis

Balantidiasis

Balantidium & Cryptosporidium  Main symptoms: Diarrhea

Simplistic Antiparasitic Primer  Roundworms:  Mebendazole  Pyratel pamoate  Thiabendazole  Ivermectin  Tapeworms:  Niclosamine  Quinacrine  Praziquantel  Flatworms:  Praziquantel  Amoebae:  Metronidazole  Paromomycin  Balantidium:  Tetracyline  Metronidazole  Cryptosporidium:  Nitazoxanide

Disclosures Images utilized in this lecture were wantonly plagiarized from the following sources:  Ash et al, Parasites: A guide to laboratory procedures and identification, ASCP  Halstead et al, Disease of Travelers and Immigrants, Scope Publications  Katz et al, Parasitic Diseases, Springer-Verlag  Markell et al, Medical Parasitology, Saunders  Meyers et al, Pathology of Infectious Diseases, Vol. 1 Helminthiases, AFIP  Peters et al, A Color Atlas of Tropical Medicine and Parasitology, Wolfe  JF Williams, personal collection  Google image search Any reference to commercial trademarks in this lecture likely causes their respective holders to cringe.