Nematodes - Intestinal Flashcards
What are the Intestinal Nematodes? (6)
- Enterobius Vermicularis
- Trichuris trichiura
- Ascaris lumbricoides
- Necator americanus
- Ancylostoma duodenale
- Strongyloides stercoralis
Enterobius Vermicularis:
-AKA
PInworm (oxyuriasis)
Enterobius Vermicularis - Adult Morphology:
- Sex
- Shape
- Cross-section
Female
- Slightly bent/pointed (pinlike) tail
- Lateral alae (characteristic)
Enterobius Vermicularis - Egg:
-Morphology (3)
*Identification
- 30-50 um
- Thin-walled
- 1 flattened side
*Cellophane tape test (NOT seen in stool)
Enterobius Vermicularis:
- Transmission
- Symptoms
- Complication
- Ingestions of Eggs
- Anal pruritis, vaginitis, and/or enuresis (urinary incontinence)
- Appendicitis
Enterobius Vermicularis:
-Adult female life
- Inhabit Cecum/Appendix
- Lay eggs in perianal region (nocturnally)
What is the most common helminthic infection in American Children?
Enterobius vermicularis (pinworm)
Trichuris trichiura:
-AKA
Whipworm
Trichuris trichiura - Adult worm:
-Morphology (2)
- up to 5 cm
- Whiplike anterior end
Trichuris trichiura - Egg:
-Morphology (4)
- 50x25 um
- Brownish Thick shells
- Barrel-Shaped
- Bilateral Polar Plugs
Trichuris trichiura:
- Infection sxs
- Complication
- Asymptomatic to Dysentery-like
- Rectal prolapse in young children
Ascaris lumbricoides:
-AKA
Roundworm
Ascaris lumbricoides - Adult worm:
-Morphology
Largest nematode
-up to 35 cm
Ascaris lumbricoides - Eggs:
-Morphology (4)
- 60 um
- Bile-stained
- Thick Hyaline shell
- Rough mammillated surface
Ascaris lumbricoides - Life cycle in humans. (6)
- Ingestion of eggs
- Hatch to produce larvae
- Larvae enter bloodstream
- Lungs (Loeffler syndrome)
- Cough, swallow
- Adults infect Duodenum
Ascaris lumbricoides:
- Symptoms
- Complications
Asymptomatic
- Bowel obstruction
- Cholangitis
- Appendicitis
Necator americanus and Ancylostoma duodenale:
-AKA
Hookworms
Necator americanus and Ancylostoma duodenale:
- Adult size
- Differing features (Mouth Parts)
-1 cm in length
Necator americanus:
-Cutting plates
Ancylostoma duodenale:
-“Teeth”
Necator americanus and Ancylostoma duodenale:
-Eggs (2)
- Thin, translucent wall
- Morula-like cluster of spherical embryos
*Indistinguishable
Where is N. americanus found?
Southeastern US
*A. duodenale NOT found in US
Necator americanus and Ancylostoma duodenale:
-Life Cycle (3)
- Larvae penetrate skin (feet)
- Lungs (cough/swallow)
- Adults infest Small bowel
Necator americanus and Ancylostoma duodenale:
-Symptoms (3)
- Pruritic lesion (ground itch)
- Loeffler syndrome
- Iron deficiency anemia
Strongyloides stercoralis:
-AKA
Thread worm
Strongyloides stercoralis - Adult worm:
- Sex
- Size
- Location
- Female
- 3 mm
- Intestinal crypts
Strongyloides stercoralis egg is identical to what other nematode?
-Stool (+/-)
Hookworm egg (N. americanus/A. duodenale) -Not typically found in stool
Strongyloides stercoralis - Eggs hatch in ____ and feces contain _____.
- Hatch in bowel
- Rhabditoid larvae in stool
How do you distinguish Strongyloides stercoralis larvae from hookworm larvae? (2)
Strongyloides stercoralis:
- Shorter buccal groove
- Prominent genital primordium
Where is Strongyloides stercoralis typically found? (3)
- Southeastern US
- Tropics
- Subtropics
Strongyloides stercoralis:
-Life cycle (4)
Similar to hookworms.
- Penetrate skin
- Migrate through lungs
- Cough/Swallow
- Duodenal infection
Strongyloides stercoralis:
-Complication in malnourished host
Autoinfection
-larvae may penetrate bowel wall, circulating through the lungs and reinfecting the duodenum
Strongyloides stercoralis:
-Complication in immunocompromised host
Autoinfection/Hyperinfection
-Disseminated larvae-Deadly
