Nematodes

Question 1

what are the 3 nematode routes of infection?

Answer 1

• ingested
• cutaneous
• bites

Question 2

species of nematodes that infect thru ingestion

Answer 2

• Enterobius
• Ascaris
• Toxocara
• Trichinella
  
  • ​“You’ll get sick if you EATT these!”

Question 3

species of nematodes that infect cutaneously

Answer 3

• Stronglyloides
• Ancylostoma
• Necator
  
  • ​”These get into your feet from the SANd”

Question 4

species of nematodes that infect thru bites

Answer 4

• Loa loa
• Onchocerca volvulus
• Wuchereria bancrofti
  
  • ​“Lay LOW to avoid getting bitten”

Question 5

explain the 2 types of immune responses to helminths

Answer 5

• eosinophils act by type I and type II hypersensitivity reactions in responding to helminths
  
  • Type I
    
    • neutralization of histamine and leukotrienes
  • Type II
    
    • eosinophils attach to surface of helminths via IgE and release cytokines (ie. major basic protein) contained in their granules

Question 6

name the 6 intestinal nematodes (roundworms)

Answer 6

• Enterobius vermicularis (pinworm)
• Ascaris lumbricoides (giant roundworm)
• Strongyloides stercoralis (threadworm)
• Ancylostoma duodenale, Necator americanus (hookworms)
• Trichinella spiralis

Question 7

Enterobius vermicularis (pinworm)–disease

Answer 7

• intestinal infection causing anal pruritus
  
  • diagnosed by seeing egg via the tape taste

Question 8

Enterobius vermicularis (pinworm)–transmission

Answer 8

• fecal-oral

Question 9

Enterobius vermicularis (pinworm)–treatment

Answer 9

• bendazoles (b/c worms are bendy)

Question 10

Ascaris lumbricoides (giant roundworm)–disease

Answer 10

• intestinal infection with possible obstruction at ileocecal valve

Question 11

Ascaris lumbricoides (giant roundworm)–transmission

Answer 11

• fecal-oral
  
  • eggs visible in feces under microscope

Question 12

Ascaris lumbricoides (giant roundworm)–treatment

Answer 12

• bendazoles

Question 13

Strongyloides stercoralis (threadworm)–disease

Answer 13

• intestinal infection causing vomiting, diarrhea, epigastric pain (may mimic peptic ulcer)

Question 14

Strongyloides stercoralis (threadworm)–transmission

Answer 14

• larvae in soil penetrate the skin

Question 15

Strongyloides stercoralis (threadworm)–treatment

Answer 15

• ivermectin
• bendazoles

Question 16

Ancylostoma duodenale, Necator americanus (hookworms)–disease

Answer 16

• intestinal infection causing anemia by sucking blood from intestinal wall
• Cutaneous larva migrans
  
  • pruritic serpiginous rash from walking varefoot on contaminated beach

Question 17

Ancylostoma duodenale, Necator americanus (hookworms)–transmission

Answer 17

• larvae penetrate skin

Question 18

Ancylostoma duodenale, Necator americanus–treatment

Answer 18

• bendazoles
• pyrantel pamoate

Question 19

Trichinella spiralis–disease

Answer 19

• intestinal infection
• larvae enter bloodstream and encyst in striated muscle cells –> inflammation of muscle
• Trichinosis
  
  • fever
  • vomiting
  • nausea
  • periorbital edema
  • myalgia

Question 20

Trichinella spiralis--transmission

Answer 20

• fecal-oral
• undercooked meat (especially pork)

Question 21

Trichinella spiralis–treatment

Answer 21

• bendazoles

Question 22

name the 4 tissue nematodes (roundworms)

Answer 22

• Toxocara canis
• Onchocerca volvulus
• Loa loa
• Wuchereria bancrofti

Question 23

Toxocara canis–disease

Answer 23

• Visceral larva migrans
  
  • nematodes migrate to blood thru intestinal wall causing inflammation and damage
  • organs frequently affected include the heart (myocarditis), liver, and CNS (seizures and coma)

Question 24

Toxocara canis–transmission

Answer 24

• fecal-oral

Question 25

*Toxocara canis*--transmission

Answer 25

* fecal-oral

Question 26

*Toxocara canis*--treatment

Answer 26

* bendazoles

Question 27

*Onchocerca volvulus*--disease

Answer 27

* skin changes * loss of elastic fibers * river blindness * **black** flies, **black** skin nodules, **"black** sight" * allergic rxn to microfilaria possible

Question 28

*Onchocerca volvulus--*transmission

Answer 28

* female blackfly

Question 29

*Onchocerca volvulus--*treatment

Answer 29

* Ivermectin * "**iver**mectin for r**iver** blindness"

Question 30

*Loa loa*--disease

Answer 30

* swelling in skin * worm in conjunctiva

Question 31

*Loa loa*--transmission

Answer 31

* deer fly * horse fly * mango fly

Question 32

*Loa loa*--treatment

Answer 32

* diethylcarbamazine

Question 33

*Wuchereria bancrofti*--disease

Answer 33

* elephantiasis * worms invade nodes and cause inflammation which can block lymphatic vessels * takes 9 mos-1 year after bite to become symptomatic

Question 34

*Wuchereria bancrofti*--transmission

Answer 34

* female mosquito

Question 35

*Wuchereria bancrofti*--treatment

Answer 35

* diethylcarbamazine