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107 Cards in this Set
- Front
- Back
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What are the 2 forms of DISEASE caused by E. histolytica |
-intestinal amebiasis -extraintestinal amebiasis |
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How does E. histolytica look in its cyst form |
small diameter, with 4 nuclei present |
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How do you diagnose E. histolytica infection |
serologic testing for antibodies, only problem is that the test wont distinguish between past and present infections |
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How does E. histolytica look like in its trophozoite form |
large diameter, with single ecentric nucleus, often with engulfed RBCs |
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True or False: There are certain non-pathogenic amoebae |
True |
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How does intestinal amebiasis present |
- cramps, diarrhea, vomitting, fever and pain, anemia
-dysentary (>30 stools per day)
** can mimic ulcerative colitis or appendicitis ** |
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What is the pathogen that causes Giardiasis |
Giardia doudenalis |
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True or False: E. histolytica is always pathogenic |
True |
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What are stages of E. histolytica's life cycle |
cyst form - tranmission and infection form trophozoite form- feeding and tissue invasive form |
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Name 3 protozoic GI pathogens |
-Entamoeba histolytica -Giardia duodenalis -Cyrptosporidium parvum |
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What is the pathogen that causes Amebiasis |
Entamoeba histolytica |
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How does extraintestinal amebiasis present |
-noted by liver abscess (anchovy paste) with (only) trophozoites present around the edge of the lesion -amoebic lung abscess also possible |
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Name 6 helminthic GI pathogens |
-Pinworm (Enterobius vermicularis) -Roundworm (Ascaris lumbercoides) and (VLM) -Whipworm (Trichuris tricuria) - Hookworm (Necator americanus & Ancyclostoma doudenale) and (CLM) -Strongyloides stercoralis -Shistosoma (5 species) |
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Who are high risk populations for Amebiasis |
-MSM engaging in unsafe sex -Residents of mental institutions (poor hygiene) -Travelers -Immigrants especially from Latin America -Low SES especially from South US
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True or False: Humans are NOT the chief source of infection of Amebiasis |
FALSE |
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True or False: Giardia duodenal is only found in human hosts |
FALSE. Giardia is also found in animal hosts (dogs, wild animals, beaver fever, possums) |
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Name the two lifecycle stages of Giardia duodenalis |
cyst form- infective stage (highly infective) trophozoite form- feeding stage
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True or False: Giardia transmission is most commonly through water |
TRUE
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How does Giardia present clinically |
severe diarrhea in some cases, cramps, flatulence, anorexia, dehydration and fatigue |
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True or False: Giardia is the most common intestinal parasite in North America |
TRUE |
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True or False: Giardia is sensitive to disinfectants and that is the primary means of treating water |
FALSE Giardia duodenalis is resistant to disinfectants, and is commonly filtered by sand |
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True or False: Stool samples of patients suspected with Giardia duodenalis contain blood and pus |
FALSE stool samples contain mucus, not pus or blood |
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True or False: Giardia duodenalis is mainly a small intestine pathogen |
TRUE
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What syndrome is Giardia duodenalis associated with and what is the logic behind it |
Giardia doudenalis is associated with Malabsorption Syndrome. Logic is that is a small intestine pathogen (site of absorption)
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Patients with Giardia will commonly present with which deficiencies |
Vitamin A deficiency Folate deficiency Vitamin B12 deficiency |
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How is Amebiasis described histologically |
Appears as a flask-shaped ulcer that does not penetrate the Muscularis externa |
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True or False: E. histolytica penetrates the submucosa |
TRUE. E. histolytica penetrates the submucosa but stops at the muscularis externa
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How does Giardia present histologically |
Giardia duodenalis penetrates the muscosa, but DOES NOT penetrate the submuscosa
-causes villi blunting |
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True or False: Giardia penetrates through the lumen until the muscularis externa |
FALSE. E. histolytica penetrates through until the muscularis externa to form the flask shaped uncler. Giardia duodenalis penetrates only the mucosa and causes villi blunting |
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How do you diagnose Giardia duodenalis |
Giardia antigen test on stool sample |
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True or False: Giardia are commonly seen as trophozoites in stool samples |
FALSE. They convert back to cyst form |
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True or False: Best method of diagnosis for Giardia is stool sample O&P |
FALSE. cysts are inconspicuous and commonly missed
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True or False: A patient with Giardia will have an increased number of goblet cells in the colon |
TRUE. This examples why stool samples are mucus rich
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True or False: Cryptosporidium parvum is a major cause of non-viral gastritis |
TRUE |
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What is the infective form of Cryptosporidium parvum |
oocyte stage
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True or False: Cryptosporidium parvum is highly sensitive to environmental stresses and disinfectants |
FALSE. It is highly highly resistant to such stresses
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What are the modes of transmission of Cryptosporidium parvum |
4 F's (feces, food, flies, fingers) but primarily waterborne
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How does Cryptosporidium parvum present in immunocompetent patients |
silent to mild diarrhea, cramps, epigastric pain, diarrhea free of mucus or blood, anorexia and fatigue
-majority of cases are self-limiting
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How does Cryptosporidium parvum present in patients who are immunocompromised |
Profuse debilitating diarrhea with >30 stools per day, severe fluid loss, malabsorption syndrome, |
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How do you diagnose patients with Cryptosporidium parvum |
Cryptosporidium antigen test on stool sample |
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What is the taxonomic name for Pinworm |
Enterobius vermicularis |
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True or False: Pinworm infections (Enterobius vermicularis) are transmitted by the fecal-oral route |
TRUE
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True or False: E. histolytica, G. duodenalis, and C. parvum are all protozoic infections and cause eosinophillia |
FALSE. They are all protozoic but they do not cause eosinophilia because they do not invade the tissue
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Describe the infection cycle of Enterbius vermicularis (Pinworm) |
1) Eggs are ingested 2) Eggs mature into larvae in the small intestines 3) Larvae migrate to colon 4) Adult larvae lay eggs on perineum - causes intense scratching 5) Soiled hands transmit eggs back to mouth |
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True or False: Pinworm (Enterobius vermicularis) has an auto-inoculative life-cylce |
TRUE |
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True or False: Pinworms (Enterobius vermicularis) infiltrate the GI lumen and can metastasize to other organs |
FALSE Pinworms stay PINNED to the GI tract |
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How do you diagnose Pinworm (Enterobius Vermicularis) |
Scotch-tape Test
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How do pinworm eggs appear histologically |
prius shape (rounded top, flat bottom)
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What is the taxonomic name for roundworm |
Ascaris lumbercoides |
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What is the route of transmission of Roundworm (Ascaris lumbercoides) |
Infection is caused via fecal contamination of food or drink |
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Roundworm (Ascaris lumbercoides) has a simple lifecycle |
FALSE. It infiltrates the lungs |
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Describe the lifecycle of the roundworm Ascaris lumbercoides |
1) Eggs ingested via fecal contaminated food 2) Travel down into intestines where larvae hatch 3) Goes up billiard tree, and migrate to the heart 4) Travel via blood to lungs, infiltrate through alveoli 5) Travel up through trachea, and go into esophagus 6) Adults mature in the small intestines and can cause complications |
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How do you diagnose roundworm Ascaris lumbercoides infection |
Identify eggs in stool sample |
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Describe the eggs of roundworm Ascaris lumbercoides |
lumpy bumpy outer appearance |
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What is the animal equivalent of roundworm Ascaris lumbercoides |
Visceral larvae migrams |
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What is the taxonomic name of whipworm |
Trichuris tricuria |
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True or False: Trichuris tricuria has a complex lifecycle |
FALSE -fecal oral cycle, limited only to GI lumen |
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How do whipworm (trichuris tricuria) eggs appear or what do they resemble? |
They resemble manicotti (stuffed shells) with little handles on each end |
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True or False: Whipworm can cause rectal prolapse in adults? |
FALSE whipworm rarely causes rectal prolapse in adults, most commonly seen in children
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How does whipworm (Trichuris tricuria) commonly present if left untreated |
Rectal prolapse in children
Think: whipworm will "whip" you until you have rectal prolapse |
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Name the 2 species of hookworms we need to know |
-Necator americanus -ancyclostoma doudenale |
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How does hookworm enter the body |
commonly through the sole of your foot (between toes)
Think: hookworm hook unto the bottom of your foot
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Describe the lifecycle of a hookworm |
1) Eggs in feces mature in soil for 3-4 days 2) Larve emerge, penetrate skin, and enter circulation 3) Larve break through alveoli, travel up trachea, and down the esophagus 4) Mature into adult form in the intestine |
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True or False: The life cycle of Hookworm is similar to that of the roundworm (Ascaris lumbercoides) |
TRUE |
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True or False: The life cycle of pinworm (Enterbius vermicularis) is similar to whipworm (trichuris tricuria) |
TRUE |
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The life cycle of which helminth closely resembles the pinworm (Enterobius vermicularis) |
Whipworm (Trichuris tricuria) |
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The life cycle of which helminth closely resembles the whipworm Trichuris tricuria |
Pinworm (Enterbius vermicularis) |
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The life cycle of which helminth closely resembles the Hookworm |
Roundworm (Ascaris lumbercoides) |
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The life cycle of which helminth closely resembles the roundworm (Ascaris lumbercoides) |
Hookworm |
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What is clinically important about hookworm infections |
They are very important causes of iron deficiency in children and young women |
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True or False: Hookworms suck blood from the small intestines |
TRUE This explains the anemia and iron deficiency seen in young women and children |
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What is the animal equivalent of Hookworm |
Cutaneous larvae migrams |
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How would a person be exposed to cutaneous larvae migrams |
sunbathing on a damp tropical beach where pets are allowed to run free |
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Name a helminths that can replicate within the human host |
Stongyloides stercoralis |
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True or False: Strongyliodes stercoralis can enter the host by burrowing through skin or feet |
TRUE |
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Describe the life cycle of Strongyloides stercoralis |
1) Larve enter human host by penetrating skin 2) Enter lymphatics or venous blood, travel to lungs, up trachea, down esophagus to intestines 3) Adult female larvae lay eggs in the mucosa of the intestine 4) Then you can either have auto-reinfection or develop free living adult larvae that will be excreted and will produce eggs. |
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True or False: Those who are immunosuppressed (AIDS or taking steroids) are at higher risk for Strongyloides stercralis auto-infection |
TRUE |
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True or False: Strongyloides stercoralis worms are commonly found in stool |
FALSE |
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How do you diagnose Strongyloides stercoralis |
Serological testing for antibodies |
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Which worms CANNOT replicate or increase in number without leaving the body |
Ascaris lumbercoides Hookworm Whipworm |
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Which worms CAN replicate and/or increase in number within the same patient |
Pinworm (Enterobius vermicularis) Strongyliodes stercoralis (but usually occurs in immunpsupressed) |
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What host is Visceral larvae migrams and Cutaneous larvae migrams associated with |
Cats and Dogs |
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Name pathogen in cats and dogs that is equivalent to the roundworm (Ascaris lumbercoides) found in humans. |
Toxocara canis - dogs Toxocara cati- cats |
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How does Visceral larvae migrams present clinically? |
Because it infects the wrong host (humans instead of cats or dogs), it triggers a vigorous immune response: -eosinophillia, skin rash, shortness or breath, abnormal chest x-ray |
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Cutaneous larve migrams is the equivalent to what human host pathogen |
Hookworm |
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How does Cutaneous larvae migrams present in human host |
itchy, serpentine tracks on feet or buttocks or skin that has been in contact with moist soil |
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What is the Genus name of "blood flukes" |
Schistosomes |
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True or False: Schistosomes (blood flukes) can be diagnosed by examining blood smears |
FALSE Stool samples and urine samples are observed for eggs |
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Name the 5 medically relevant Schistosome species |
S. mansoni S. haematobium S. Japonicum S. mekongi S. intercalatum |
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The life cycle of Schistosomes requires what animal reservoir |
fresh water snails |
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Where do Schistosomes preferably like to reside in the human host |
inferior mesenteric artery |
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True or False: Schistosome species can be distinguished based on the spine of eggs |
TRUE |
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Which species of Schistosome has a terminal spine on its egg |
S. haemotobium |
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Which of the Schistosome species has a lateral spine on its egg |
S. mansoni |
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Which of the Schistosomes species is most widely distributed, and where is it generally found |
S. mansoni -commonly found in central Africa, along the cost of Brazil , and in the Caribbean |
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Where is Schistosome mansoni generally found geographically |
Central Africa (Nile River Valley), coast of Brazil, and the Caribbean |
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Where is Schistosome haematobium generally found geographically |
Central Africa (Nile River Valley)
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Patient returns home from Central Africa (Nile River Valley Region), and clinical presentation aligns with Schistosome infection. Which specie(s) are likely to be identified |
S. haematobium and S. mansoni |
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Schistosome haematobium is commonly isolated from what tissue |
Eggs are commonly found in the wall of the urinary bladder |
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Schistosome mansoni is commonly isolated from what tissue |
Eggs can be observed in the liver |
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Describe the body of the Schistosome worm |
Male Schistosomes have a cleft in their body where female schistosomes can snuggle into
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How do you diagnose Schistosomiasis |
Look for eggs in stool or urine, distinguish species based on spine |
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There has been a development of a new rapid diagnostic field test (urine test) for which species of Schistosome |
S. haematobuim |
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What is the condition caused by the animal (bird) equivalent of Schistosome |
Swimmers itch |
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How does Swimmer Itch present |
Severe cutaneous rash |
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Where is Swimmers Itch most commonly found geographically |
In small pounds surrounding the great lakes
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How do you treat Swimmers Itch |
No anti-parasitic medication is necessary. Could use topical steroid cream to decrease inflammatory response
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