GI parasitic roundworms

Question 1

What are the properties of nematodes?

Answer 1

1. Non-segmented bodies 2. Separate sexes 3. Complete digestive system

Question 2

What are the properties of cestodes?

Answer 2

1. Segmented bodies 2. Hermaphroditic 3. Absorb nutrients

Question 3

What are the properties of trematodes?

Answer 3

1. Non-segmented (leaf-shaped) 2. Hermaphroditic 3. Primitive gut

Question 4

What is required to shed eggs in a nematode infection?

Answer 4

A male and a female nematode

Question 5

Do adult nematodes replicate in the host?

Answer 5

No

Question 6

What are the two groups of geohelminths?

Answer 6

1. Ascaris and trichuris - ingestion of infectious eggs 2. Strongyloides and hookworms - penetration of skin by infectious larvae in soil

Question 7

What is the genus and species of pinworm?

Answer 7

Enterobius vermicularis

Question 8

What is the treatment for pinworms?

Answer 8

Mebendazole, pyrantel pamoate - single dose, repeated two weeks later

Question 9

What is the genus and species of whipworm?

Answer 9

Trichuris trichiura

Question 10

What are the symptoms of whipworm infection?

Answer 10

1. Heavy worm burden 2. Bloody, mucous containing diarrhea 3. Frequent stools 4. Rectal prolapse in children

Question 11

What is the organism associated with ascariasis?

Answer 11

Ascaris lumbricoides

Question 12

What are the characteristics of pulmonary disease associated with ascariasis?

Answer 12

1. Combination of physical presence of larvae and immune response to them 2. Mild cough, pneumonitis 3. Parasite antigens highly allergenic 4. Eosinophilia

Question 13

What is the diagnosis for ascariasis?

Answer 13

1. Eggs in stool 2. Larvae or eosinophilia in sputum

Question 14

What are the genus and species names of hookworm?

Answer 14

1. Necator americanus 2. Ancylostoma duodenale

Question 15

What is the life cycle of hookworms?

Answer 15

1. Infective larvae penetrate skin from soil 2. Circulation - lungs - trachea - pharynx - swallowed 3. Adults attach to small intestine 4. Diagnostic stage - eggs in feces

Question 16

What are the clinical manifestations of hookworm infection?

Answer 16

1. Iron-deficiency anemia due to blood loss from hookworm feeding 2. Moderate dermatitis at site of penetration 3. Pnuemonia and eosinophilia

Question 17

What is the cause of strongyloidiasis?

Answer 17

Strongyloides stercoralis

Question 18

What are the features of strongyloidiasis?

Answer 18

1. Facultative parasite - can be a free living nematode in soil 2. Larvae passed in stool 3. Worms produce eggs in soil, not intestines 4. Infectious larval form can develop in intestine, enter circulation, and re-initiate infection

Question 19

What is the main cause of strongyloides hyperinfection and disseminated disease?

Answer 19

Immunosuppression

Question 20

What is the diagnosis for strongyloidiasis?

Answer 20

Larvae in stool

Question 21

Which nematode egg is flat on one side?

Answer 21

Enterobius vermicularis - pinworm

Question 22

Which nematode egg is lemon / barrel shaped?

Answer 22

Trichuris trichiura - whipworm

Question 23

Which nematode egg is lumpy / bumpy?

Answer 23

Ascaris lumbricoides

Question 24

Which nematode egg is “boring / plain”?

Answer 24

Hookworm (necator americanus, ancylostoma duodenale)

Question 25

Enterobius vermicularis (pinworm) has what kind of egg morphology?

Answer 25

Flat on one side

Question 26

Trichuris trichiura (whipworm) has what kind of egg morphology?

Answer 26

Lemon / barrel shaped

Question 27

Ascaris lumbricoides has what kind of egg morphology?

Answer 27

Lumpy / bumpy

Question 28

Hookworm eggs have what type of morphology?

Answer 28

“Boring / plain”