Helminths

Question 0

Enterobius (pinworm)

Answer 0

5-15 mm long nematode,
Sx: perianal itching, –> appendicitis, peritoneal granulomas
transmission: Fecal-oral.
treatment: albendazole/mebendazole

Question 1

immune response to helminths

Answer 1

Th2 response with eosinophils
(eos. = activated by IL-5, w/ Rs for IgE)
bc worms = too big for phagocytosis.

Question 2

Enterobius (Pinworm) life cycle

Answer 2

1. eat/inhale eggs,
2. replicate in sm/lg intestine,
3. mature female to anus –> expels eggs
   (cling to sides –> perianal itching)

Question 3

Ascaris (roundworm) life cycle

Answer 3

1. eat eggs (from feces)
2. hatch in sm. intestine
   - -> move to liver, lungs
3. coughed up and swallowed
4. mature and reproduce in sm. intestine (stay indefinitely)

Question 4

Ascaris (roundworm) infection

Answer 4

large nematode,
Sx: “Loeffler’s Syndrome” (cough, fever, dyspnia)
- Lungs: pneumonia w/ patchy infiltrates
- Sm. Intestine: asymptomatic OR intestinal obstruction
Treatment: Albendazole/mebendazole

Question 5

Trichuris (whipworm) infection

Answer 5

2 in. long nematode,
Sx: mucosal damage –> anemia, bleeding; growth retardation, abdominal pain, diarrhea.
Treatment: albendazole/mebendazole
** infection could be beneficial for IBS patients (reduce inflammation)**

Question 6

Trichuris (whipworm) life cycle

Answer 6

1. consume eggs
2. hatch in sm/lg. intestine
3. mature and lay eggs (still in sm/lg. intestine)
4. eggs passed w/ feces, can survive in warm soil for 10 days

Question 7

Wolbachia

Answer 7

rickettsia-like bacteria necessary for some worm infections to be successful in humans.
–> treating w/ doxycycline can disrupt worm life cycle AND control some symptoms of infection

Question 8

Hookworm infection

Answer 8

(by Ancylostoma or Necatur worms)
Sx: 1. Loeffler’s; 2. Hepatosplenomegaly, weight loss, anemia, abd. pain, diarrhea, +/- physical/mental retardation (children)
Transmission: through bare feet (= in soil)
Treatment: albendazole

Question 9

Hookworm life cycle

Answer 9

1. penetrate skin on feet/ankles
2. travel to lungs via blood
3. coughed up and swallowed
4. larvae mature in sm. intestine
5. eggs pass w/ feces, can survive in soil 6 wks

Question 10

Strongyloides infection

Answer 10

Sx: 1. Loeffler’s syndrome/pneumonitis;
2. abd. pain, diarrhea/constipation, malabsorption
* Risk: gram neg. shock (from bacteroides/prevotella co-infection)
Dx: serpentine lesions just below skin.
Transmission: through bare feet
treatment: albendazole

Question 11

Strongyloides life cycle

Answer 11

• just like hookworm life cycle:
  1. in via skin on foot/ankle
  2. via blood to lungs, coughed up and swallowed
  3. mature in sm. intestine
  4. eggs out w/ feces, live in soil up to 6 wks

Question 12

Trichinosis infection

Answer 12

Sx: muscle weakness, nausea/fever/diarrhea, myositis/granulomas, cyst formation in heart/brain/lungs (!)
* = type I hypersensitivity
Transmission: eat undercooked game (ie: bear)
Treatment: corticosteroids and mebendazole

Question 13

Wucheria

Answer 13

–> “elephantiasis” (delayed-type hypersensitivity)
Sx: permanent lymphatic blockage and tissue damage, + fever.
transmission: mosquitos
treatment: Antihistamines, corticosteroids, diethylcarbamazine

Question 14

filarial life cycle (ie: Wucheria, Loa, Onchocerca, Dracunculus)

Answer 14

1. microfilaria (embryos) taken into insect vector
2. larvae passed to insect feces
3. feces + larvae left at site of bite (to human), penetrate skin w/ scratching

Question 15

Loa Loa infection

Answer 15

(filarial worm)
Sx: intense eye pain and tearing, temporary blindness.
(no lasting damage) * type I hypersensitivity*
transmission: Deerfly bite (W. Africa)
treatment: diethycarbamazine

Question 16

Onchocerca infection

Answer 16

(filarial worm)
Sx: blindness, nodules at site of bite
Transmission: bite from simulium (“buffalo gnat”)
treatment: Ivermectin OR diethylcarbamazine and corticosteroids

Question 17

Dracunculus infection

Answer 17

(filarial worm) “Guinea worm”
Sx: skin ulcers (type I hypersensitivity), high risk 2nd bacterial infection
transmission: via fleas IN drinking water
treatment: metronidazole (also, filter water)

Question 18

Taenia (tapeworm) infection

Answer 18

Sx: weight loss, abdominal discomfort, developmental issues.

• • Cysticerosis = more severe…
    transmission: undercooked pork
    treatment: Praziquantel

Question 19

Cysticerosis

Answer 19

severe form of tapeworm (Taenia) infection,
Sx: acquired epilepsy, CNS problems
transmission: fecal-oral (of human feces w/ taenia eggs)
treatment: Praziquantel (same as other Taenia infections)

Question 20

Schistosomes (“blood flukes”)

Answer 20

Sx:
- acute: jaundice, liver pain, fever, malaise, hives, CNS issues.
- Chronic: hepatic granulomas, cramps/cough, hematuria/dysuria
- swimmer’s itch: rash/lesions, fever/malaise,
*IgE-med. hypersensitivity.
Transmission: #1 snails, also: birds
Treatment: Praziquantel (Cortisone cream for swimmer’s itch)