Parasitology II: Helminths

Question 1

What is the most common worm infection in the United States?

Answer 1

Enterobius vermicularis

Question 2

How is Enterobius vermicularis transmitted?

Answer 2

Fecal-orally

Question 3

Pathogenesis of Enterobius vermicularis

Answer 3

Attaches to the wall of the colon and migrates through the anus where it hatches eggs

Question 4

Symptoms of Enterobius vermicularis

Answer 4

Anal itching

Can lead to secondary bacterial infection

Question 5

Diagnosis of Enterobius vermicularis

Answer 5

E. vermicularis worms stain orange with Papanicolau stain

Question 6

Treatment of Enterobius vermicularis

Answer 6

Pyrantel pamoate
Mebendazole
Albendazole

Question 7

What is the distribution of Trichuris trichiura?

Answer 7

Southern United States

Question 8

What is the route of transmission of Trichuris trichiura?

Answer 8

Fecal-oral

Question 9

What are the symptoms of Trichuris trichiura?

Answer 9

Heavy infections: Bloody diarrhea, rectal prolapse

Question 10

What is the treatment of Trichuris trichiura?

Answer 10

Mebendazole

Albendazole

Question 11

What is the distribution of Ascaris?

Answer 11

Uncommon in the U.S.

If seen, it is seen in the SE

Question 12

What do the Ascaris eggs look like?

Answer 12

Rough coat

Question 13

What are the symptoms of Ascaris?

Answer 13

Light infection: Asymptomatic

Heavy infection: Wheezing, SOB, malabsorption of food, intestinal obstruction

Question 14

Diagnosis of Ascaris

Answer 14

ID of eggs in the feces

Finding of worms leaving the body

Question 15

Treatment of Ascaris

Answer 15

Mebendazole
Albendazole
Ivermectin
Pyrantel pamoate (pregnant individuals)

Question 16

What is the distribution of Necateur americanus?

Answer 16

Prevalent in Central and South America

Question 17

What is the mechanism of infection of Necateur americanus?

Answer 17

Eggs hatch to larval stage in the environment. Larvae then penetrate the skin. Mature to adults in the small intestine.

Question 18

What are the risk factors for Necateur americanus?

Answer 18

Not wearing shoes

Question 19

Symptoms of Necateur americanus

Answer 19

"Ground Itch", usually in the soles of the feet
Most cases are asymptomatic.
Blood loss (causing anemia), gastric pain, pulmonary manifestations (not as severe as Ascaris)

Question 20

Where is Strongyloides stercoralis found?

Answer 20

Southern U.S.

Question 21

What kind of life cycle does Strongyloides stercoralis have?

Answer 21

It has a Direct Cycle and an Autoinfective Cycle

Question 22

Symptoms of Strongyloides stercoralis

Answer 22

Pulmonary & GI symptoms

Hallmark feature is peptic-ulcer like pain with peripheral eosinophilia

Question 23

Diagnosis of Strongyloides stercoralis

Answer 23

“Larva currens”…raised “creeping” red lesion over the buttocks or lower back
Shows “trails” of bacteria on a blood agar plate

Question 24

Treatment for Strongyloides stercoralis

Answer 24

Ivermectin

Question 25

Where is Ancyclostoma duodenale distributed?

Answer 25

Americas, Middle East, Africa

Question 26

What is the life cycle of Ancyclostoma duodenale?

Answer 26

Eggs hatch to larvae outside the body. Larvae penetrate the skin.

Question 27

Diagnosis for Necateur/Ancyclostoma

Answer 27

Examine stool for worm eggs | Necateur and Ancyclstoma eggs are indistinguishable

Question 28

Treatment for Ancyclostoma/Necateur

Answer 28

Pyrantel pamoate

Question 29

What is the distribution of Ancyclostoma braziliense?

Answer 29

Tropical & subtropical regions

Question 30

What is the life cycle of Ancyclostoma braziliense?

Answer 30

Larvae hatch from eggs in dog/cat feces

Question 31

What are the risk factors for Ancyclostoma braziliense?

Answer 31

Larvae contaminated sand (Beachgoers or sandbox) | Close contact with dogs/cats

Question 32

Symptoms of Ancyclostoma braziliense

Answer 32

Cutaneous larval migrans. Scratching it can lead to secondary infection. 50% of individuals develop Loffler's Syndrome (Migratory pulmonary infiltrates associated with peripheral eosinophilia)

Question 33

Diagnosis of Ancyclostoma braziliense

Answer 33

"Creeping eruption" Long red raised pruritic lesion Pulmonary manifestations

Question 34

Treatment of Ancyclostoma brazilense

Answer 34

``` Albendazole Ivermectin Topical Thiabendazole Anti-histamines Antibiotics ```

Question 35

What is the life cycle of Toxocara canis?

Answer 35

Eggs eaten by dogs

Question 36

Who is at risk to get Toxocara canis?

Answer 36

Young children and dog owners

Question 37

What are the symptoms of Toxocara canis?

Answer 37

Visceral Larva Migrans Ocular Larva Migrans Unilateral strabismus. Decreased vision Will see Granulomatous endophthalmitis on eye exam (white spots in the retina)

Question 38

Diagnosis of Toxocara canis

Answer 38

Larvae in liver biopsy | Eosinophilic leukocytes

Question 39

Treatment

Answer 39

Anti-helminthes | Corticosteroids

Question 40

What is the distribution of Baylisacaris procyonis?

Answer 40

U.S., Europe, Japan

Question 41

What animal is Baylisacaris procyonis associated with?

Answer 41

Racoons

Question 42

What are the risk factors for Baylisacaris procyonis?

Answer 42

Anyone around racoons

Question 43

Symptoms of Baylisacaris procyonis

Answer 43

Similar to Toxocara canis, but more severe | Loss of coordination, muscle control, blindness, coma

Question 44

Diagnosis of Baylisacaris procyonis

Answer 44

Sensitivity to light on eye exam, inflammation of the eye | Eosinophilic pleocytosis, peripheral eosinophilia

Question 45

Treatment of Baylisacaris procyonis

Answer 45

None are considered truly effective | Albendazole

Question 46

What animal is Taenia solium associated with?

Answer 46

Pigs

Question 47

Symptoms of Taenia solium

Answer 47

Cysterci develop in eyes, muscles, and brain

Question 48

Diagnosis of Taenia solium

Answer 48

Eggs/proglottids in stool | CT the brain for neurocysticerosis

Question 49

Treatment for Taenia solium

Answer 49

Albendazole | Praziquantel

Question 50

What animal is Trichinella spiralis associated with?

Answer 50

Wild game (bear, cougar, boar)

Question 51

Symptoms of Trichinella spiralis

Answer 51

Eyelid swelling, small hemorrhages beneath the fingernails Hemoptysis EKG anomalies

Question 52

Diagnosis of Trichinella spiralis

Answer 52

Swirls on H&E stain (eosinophilic)

Question 53

Treatment of Trichinella spiralis

Answer 53

Mebendazole | Albendazole