17 - Nematodes
Terms
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- Nematodes =
- roundworms
- Most intestinal worms cause little pathology, except that they may cause ______
- obstruction
- Nematode that can often cause anemia
- Hookworms = Necator Americanus
- Nematode that may PROLIFERATE and disseminate in IC'ed host
- Strongyloides Stercoralis
- Trichinella is acquired from ________
- undercooked pork
- Adult Trichinella form in the __1__, produce ~__2__, then are passed in the feces
-
1. gut
2. 200 larvae - Trichinella larvae migrate into the __1__, where they produce __2__ and __3__
-
1. skeletal muscle
2. myalgia
3. Eosinophilia -
Trichinellosis:
-Reservoir in __1__
-__2__ ingested from uncooked meat
-larvae mature into adults in the __3__
-adults mate and eggs mature to larvae
-larvae penetrate intestinal wall into the __4__
-Larvae carried to __5__ -
1. Pigs (rodents, pig then eat rodents)
2. Encysted larvae
3. SI
4. bloodstream
5. Skeletal Muscle - Trichinellosis can present as this (other than myalgia)
- Periorbital Edema with Conjunctivitis
-
Ascaris Lumbricoides:
-Adult worm length: 1
-Larvae hatch in the __2__, then migrate thru tissue to the __3__, are then __4__ and mature in the __5__ -
1. 10-14 inches
2. gut
3. lungs (via blood)
4. swallowed
5. Gut - Ascaris Lumbricoides __1__ are passed in the feces, where they may infect another human via __2__
-
1. eggs
2. fecal-oral - Rarely, Ascaris may cause these things
- Obstruction of Colon, appendix, biliary tree
- Ascaris larvae migration may induce ________
- Eosinophilic Pneumonitis
- Treatment for Ascaris
- Mebendazole, Albendazole
- Histology of Ascaris from stool specimen
- Eggs have a rough surface (jagged)
- Hookwork =
- Necator Americanus
- Necator Americanus transmission
- entry of soil larvae through intact skin
- Explain the life cycle of Necator Americanus
-
1. Larvae entry thru skin
2. Bloodstream -> lungs
3. Trachea migration -> swallowed
4. Mature in SI - Most common symptom of Necator Americanus
-
Anemia usually in children
*individual adult worm may drink .2 ml of blood per day - Degree of anemia by Necator Americanus depend on what?
- # of adult worms due to how many you ingest (do not multiply)
- Necator Americanus secretes ________
- Anticoagulant to maintain blood flow
- Secondary symptom due to Anemia from Necator Americanus
- Pitting edema
- Necator Americanus effect on heart?
- Myoglobin resorption due to lack of Hemoglobin which can result in heart failure
- What happens to Necator Americanus if the stool sample is not taken directly to the lab?
-
The larvae may hatch which might resemble Strongyloides
(refrigerate if not giving to lab immediately) - Trichuris Trichiuria =
- Whipworm
- Trichuris Trichiuria trasmission
- Fecal-oral
- Trichuriasis is common in these places of the world
- Tropical and sub-tropical areas
- # of people infected with Trichuriasis worldwide
- 500 million
- Symptoms of Trichuris
-
Diarrhea
Tenesmus
Rectal Prolapse - Histology of Trichuris
- Barrel-shaped eggs with Bipolar plugs
- Strongyloides Stercoralis unique feature
-
only worm that multiplies in IC'ed host (all others to do multiply inside host) = Autoinfection
*immunity is what keeps these in check* - Common places for Strongyloides
-
SE Asia
Vietnam-era veterans - Transmission of Strongyloides
- Fecal-cutaneous route (via feet usually)
- Stool findings with Strongyloides
- Larvae BUT NO eggs
- Toxocara canis and cati can cause a syndrome called __________
- Visceral Lavra Migrans = wander aimlessly ntil
- Serology rates of Toxocariasis in humans
- 3-50%
- In toxocariasis, usually only the __1__ is affected, although the larvae can end up anywhere, causing __2__
-
1. eye
2. Eosinophilic pneumonia - Transmission of Toxocara
- from handling dogs or cats and Larvae are ingested
- Symptoms of Toxocara
-
Cataract
Retinitis - Most common helminth in this part of the world
- Necator Americanus
- Most common helminth worldwide
- Ascaris Lumbricoides
- 2 nematodes that are trasmitted Fecal-Cutaneously
-
Necator Americanus
Strongyloides Stercoralis -
Parasite?
What does it cause?
How is it transmitted? -
Trichinella spiralis
Myalgia
uncooked pork -
Parasite that causes Appendicitis? - Ascaris Lumbricoides
-
Parasite that causes Colonic Obstruction? - Ascaris Lumbricoides
-
Parasite? - Ascaris Lumbricoides
-
Parasite that causes Biliary Obstruction? - Ascaris Lumbricoides
-
Parasite egg with Rough Edges - Ascaris Lumricoides
-
Parasite? -
Necator Americanum
-inflammation at entry site
-anemia
-pitting edema
-cardiac "tiger stripes" = myoblobin substituted for Hb -
Parasite that causes resorption of Myoglobin due to low Hemoglobin? - Necator Americanus
-
Parasite?
What does it cause?
How is it transmitted? -
Necator Americanus
Anemia
Soil larvae -> feet -
Parasite? - Trichuris Trichiuria
-
Parasite? -
Strongyloides Stercoralis
fecal-CUTANEOUS -
Parasite that causes "Visceral Larva Migrans" that either ends up in eye or Eosinophilic pneumonia - Toxocara Canis