2.03 & 2.04 Parasitic Infections GI

Question 1

How are GI protozoal infections acquired?

Answer 1

Fecal-oral transmission via contaminated food/water

Question 2

what is the role of specific morphological forms of protozoal life cycles?

Answer 2

Cysts (Infective, environ resistant) & Trophozoites (Active, motile causing pathology)

Question 3

Ingestion of infectious oocysts in water or food characteristic of?

Answer 3

Cryptosporidium spp.

Question 4

Cysts survive in cold water; trophozoites emerge in the small intestine characteristic of?

Answer 4

Giardia intestinalis

Question 5

Cysts ingested; trophozoites form in the gut characteristic of?

Answer 5

Entamoeba histolytica

Question 6

Watery diarrhea; diagnosed using acid-fast stain, ELISA, or PCR for oocysts

Answer 6

Cryptosporidium spp

Question 7

Greasy, foul-smelling stools without blood; identified via DFA or fecal antigen tests.

Answer 7

G. intestinalis

Question 8

Bloody diarrhea, flask-shaped ulcers; diagnosed by stool microscopy (at least 3) for cysts/trophozoites

Answer 8

E. histolytica

Question 9

Basic prevention of protozoal infections?

Answer 9

Water/food safety (e.g., boiling water), proper sanitation/hygiene, education on safe practices in endemic areas

Question 10

Immunocompromised hosts with parasitic diseases at higher risk of systemic complications like what?

Answer 10

liver abscesses (amebiasis) and more chronic/severe disease (ex. chronic cryptosporidiosis in AIDS)

Question 11

Giardiasis and cryptosporidiosis tend to be what in healthy hosts?

Answer 11

self limiting

Question 12

What are the transmission pathways of intestinal nematode infections?

Answer 12

Fecal-Oral Transmission and Skin Penetration

Question 13

Ascaris lumbricoides is spread via?

Answer 13

fecal-oral

Question 14

Trichuris trichiura is spread via?

Answer 14

fecal-oral

Question 15

What two nematodes have larvae that penetrate the skin?

Answer 15

Hookworms & Strongyloides stercoralis

Question 16

How are nematode infections diagnosed?

Answer 16

Identification of characteristic eggs in stool + Scotch tape test

Question 17

Stool sample lemon-shaped eggs indicative of what?

Answer 17

Trichuris trichiura

Question 18

What diagnostic test for Enterobius?

Answer 18

Scotch tape test (pinworm)

Question 19

basic prevention for nematode infections?

Answer 19

Proper sanitation to prevent soil contamination, Avoid walking barefoot, regular deworming and hygiene education

Question 20

Which nematodes replicate in the environment?

Answer 20

Strongyloides stercoralis

Question 21

public health implications of nematodes that replicate in environment?

Answer 21

Persistent infection (autoinfection) & Challenges in eradication

Question 22

What are the clinical complications of chronic intestinal nematode infections?

Answer 22

Anemia, Malnutrition, even Rectal Prolapse

Question 23

Severe Trichuris infections in children can lead to what complication?

Answer 23

Rectal Prolapse

Question 24

Leaf-shaped; incomplete gut; require intermediate hosts

Answer 24

Trematodes
(Flukes)

Question 25

Cylindrical, non-segmented; complete digestive system

Answer 25

Nematodes (Roundworms)

Question 26

Flat, ribbon-like; segmented body (proglottids); absorb nutrients directly

Answer 26

Cestodes (Tapeworms)

Question 27

Larvae encyst in tissues (e.g., brain), causing seizures and neurological deficits.

Answer 27

Cysticercosis via Taenia solium

Question 28

Hydatid cysts in liver/lungs, causing mass effects or rupture complications.

Answer 28

Echinococcosis via Echinococcus granulosus

Question 29

What are the transmission pathways of Cestodes?

Answer 29

Ingestion of encysted larvae in undercooked meat

Question 30

What are the transmission pathways of Trematodes?

Answer 30

Consumption of contaminated aquatic plants, fish, or crustaceans with metacercariae

Question 31

What diagnostic tools are used for cestode and trematode infections?

Answer 31

Stool examination for eggs/proglottids OR Imaging (e.g., CT/MRI) for cysticercosis or echinococcosis

Question 32

Basic prevention for cestode and trematode infections?

Answer 32

Proper cooking of meat/fish & Sanitation and control of intermediate hosts (e.g., snails).

Question 33

What is the diagnostic correlation of elevated eosinophil levels in helminthic infections?

Answer 33

Larval migration stages or systemic infections

Question 34

Who do you typically see E. histolytica (bloody diarhea) infections with?

Answer 34

travelers to tropical regions, immigrants, poor sanitation for institutionalized residents

Question 35

What will you find in non diarrhea stool samples of E. histolytica?

Answer 35

cysts with four nuclei

Question 36

What is path pneumonic in a intestinal biopsy for E histolytica or amebic infection?

Answer 36

flask shaped ulcer

Question 37

Amebiasis complications?

Answer 37

granulomatous lesions in cecum/rectosigmoid colon OR liver abcess

Question 38

Common demographic of people with giardiasis?

Answer 38

hikers that drink stream water + people with untreated well water

Question 39

Giardiasis transmission?

Answer 39

(most) contaminated water BUT ALSO uncooked veggies/fruits & person-person (fecal-oral-anal)

Question 40

Common worldwide cause of travelers diarrhea?

Answer 40

giardia intestinalis

Question 41

about how many infected carriers with giardiasis are asymptomatic and how long are they infectious for?

Answer 41

50% and they shed cysts for years

Question 42

what condition predisposes people for giardiasis?

Answer 42

IgA deficiency

Question 43

Why are fatty stools often seen in chronic giardiasis versus the watery in acute?

Answer 43

malabsorption of fat and protein at small intestine (weight loss + vit deficiency)

Question 44

Best choice to diagnose giardiasis?

Answer 44

Direct Fluorescent Antibody (DFA) testing

Question 45

How long to boil water?

Answer 45

1 minute (3 min at high altitudes)

Question 46

Chronic diarrhea in AIDs patients?

Answer 46

Cryptosporidium spp

Question 47

Associated with water activity (lake, pools, etc.) outbreaks in US peak early summer to fall and is the leading cause of self-limiting diarrhea in healthy people (persistent malnutrition in children) ?

Answer 47

cryptosporidiosis

Question 48

Watery diarrhea = Giardia or Cryptosporidium?

Answer 48

Down to history vs. diagnostic tests

Question 49

in what condition are oocysts immediately infectious/pathogenic from the get go?

Answer 49

cryptosporidosis

Question 50

More sensitive and quicker than acid fast direct microscopy for cryptosporidium spp?

Answer 50

ELISA or DFA (fecal antigen) NOTE PCR for species types

Question 51

Outbreaks associated with imported fresh produce in spring/summer from tropical/subtropical areas?

Answer 51

Cyclosporiasis

Question 52

How is Cyclosporiasis is different from crypto?

Answer 52

longer duration (over 2 weeks) and can detect under UV light and requires treatment

Question 53

What is very similar to cyclosporiasis?

Answer 53

cystoisosporiasis

Question 54

What helminth has separate sexes?

Answer 54

nematodes/roundworms

Question 55

what helminth has a complete digestive system?

Answer 55

nematode/roundworm

Question 56

Who are most likely to develop symptomatic infection from nematodes?

Answer 56

children (5-14)

Question 57

What form of nematodes make them most pathogenic to host?

Answer 57

adult forms

Question 58

then most common helminth infection in the US?

Answer 58

enterobius vermicularis (human pinworm)

Question 59

severe perianal itching at night, insomnia, teeth grinding? why?

Answer 59

enterobius vermicularis (mature pregnant female lays eggs there)

Question 60

Key strategy to catch and treat pinworms?

Answer 60

scotch tape test in morning and treat everyone in the household

Question 61

where is trichuris trichiura infection located?

Answer 61

cecum and colon

Question 62

round worm (ascaris lumbricoides) infection location?

Answer 62

jejunum (obstruction risk)

Question 63

Eggs with polar plugs?

Answer 63

trichuris trichiuria (whip worm)

Question 64

eggs with thick shell?

Answer 64

ascaris lumbricoides

Question 65

eggs with thin shell?

Answer 65

hookworms (necator/ancylostoma)

Question 66

rhabditiform larvae?

Answer 66

strongyloides stercoralis

Question 67

intestinal blockage, mild to sever cough, eosinophilia, abdominal pain, vomiting,, diarrhea

Answer 67

ascariasis

Question 68

most asymptomatic but if heavy worm burden, bloody painful diarrhea, rectal prolapse (children), chronic: growth impair/anemia/cognition impairment

Answer 68

trichuriasis

Question 69

the major cause of iron deficiency anemia in children and women

Answer 69

hookworms

Question 70

koilonychia, exertional dyspnea, heart murmurs, dermatitis, pneumonia, eosinophilia

Answer 70

hookworm

Question 71

can distinctly replicate in the human host and free living environment + autoinfection post skin penetration

Answer 71

strongyloides stercoralis

Question 72

high worm burden eosinophila, dry cough, diarrhea, vomiting, can migrate to lung, CNS, liver, and kidneys in immunosuppressed people

Answer 72

strongyloides stercoralis

Question 73

When infected from pork meat cysts it causes minimal symptoms

Answer 73

T solium

Question 74

When infected from eggs from infected humans it can have mass effect to CNS, seizures, hydrocephalus, and arachnoiditis

Answer 74

T solium

Question 75

transmission from cysts in beef and can cause abdominal discomfort and proglottid migration

Answer 75

T saginata

Question 76

from freshwater fish cysts that has minimal symptoms but can cause it b12 deficiency

Answer 76

diphyllobothrium latum

Question 77

eggs from infected dogs or sheep, cattle, etc. that can have mass effect to pain, obstruction of organs, or secondary bacterial infections

Answer 77

Echinococcus granulosus aka hydatid cyst disease (CE)

Question 78

raw or undercooked meat transmission, most asymptomatic but can have abdominal pain, loss of appetite, weight loss, nause/upset, complication cysticercosis with active proglottids in stool

Answer 78

taeniasis

Question 79

the leading cause of adult-onset seizures in low-income countries (brain, muscles, eyes)

Answer 79

cysticercosis

Question 80

taeniasis diagnosis?

Answer 80

stool samples on 3 different days and microscope view

Question 81

the largest tapeworm that can infect humans?

Answer 81

Diphyllobothrium latum

Question 82

dog tapeworm?

Answer 82

echinococcus

Question 83

What always serves as the first intermediate host for trematodes (flukes) to complete the life cycle?

Answer 83

mollusks (snails + clams)

Question 84

water plants, largest intestinal fluke, symptoms related to worm load, South and SE Asia,

Answer 84

fasciolopsis buski

Question 85

aquatic plants, infects bile ducts and the liver causing migration-related and chronic biliary symptoms, especially in sheep regions

Answer 85

fasciola hepatica

Question 86

undercooked fish, Chinese liver fluke, colonizes bile duct, cholangiocarcinoma (bile duct cancer), jaundice, hepatomegaly, gallstones, east asia

Answer 86

clonorchis sinensis