Nematodes

Question 1

Phylum nematoda (thread worms)

Answer 1

free living parasitic species, dioecious (hermaphrodites), unsegmented, body filled w/pressurized fluids, epidermis covered w/ tought cuticle, development of worm requires molting. Supepidermal, longgitudinal muscles, and hydroskeleton allows for wriggling. Complete digestive system (tube within a tube).

Transmission is ingestive or invasive

Question 2

nematodes or roundworms

Answer 2

worm>location>transmission

• Enterobius vermicularis>intestine/anus>direct egg fecal/oral auto infection
• Trichuris trichiura>intestine/soil>soil egg fecal/oral
• Ascaris lumbricoides>intestine/soil> soil egg fecal/oral
• Necator americanus>intestine/soil>soil larva invasion of skin
• Strongyloides stercoralis>intestine/soil>soil larva invasion of skin auto infection
• Trichinella spiralis>intestine/muscle>cyst from undercooked pork
• Toxocara canis>Many organs/soil> soil egg/ oral

Question 3

Enterobius vermicularis

Answer 3

Transmission: eating eggs, autoinfection
epidemiology: kids all over the world
Pathology: enterobiasis (itching of anus), secondary infections, worms can migrate in vagina, psychological trauma
Diagnosis: anal itching, scotch tape
Immunity: none
Treatment: Bendazoles, pyrantel pamoate

Question 4

Trichuris Trichiura (Whipworm)

Answer 4

Humans are the only host: humans poop out unemryonated eggs, eggs go thru soil stage (ebryonate), humans eat unemryonated eggs

Transmission: eating eggs, no direct person to person
Epidemiology: tropics (US South) poor hygiene, human fertilizer
Pathology: Trichuriasis (depends on worm burden) intestinal issues (none to lots)
Diagnosis: bile stained eggs in stool
Immunity: some immunity in natural infections
Treatment: Bendazoles, ivermectin + iron supplementation

Question 5

Ascaris Lumbricoides (round worm)

Answer 5

humans are the only host! human poops fertilized egg, goes thru soil stage, human eats the egg/larva, penetrates intestines and goes to lungs, coughed up and swallows the adult worm.

Epidemiology: Appalaschia and South
Pathology: low to high intestinal and liver problems
Immunity: iinflammation in lungs
Diagnosis: bile stained fertilized and unfertilized eggs
Treatment: bendazoles, ivermectin

Question 6

Hookworms (Necator Americanus and Ancylostoma duodenale)

Answer 6

human poops out egg, develops in soil, penetrates the skin (filariform larvae), lung to intestines
Pathology: rash, anemia, eosinophilia
Immunity: inflammation
Diagnosis: eggs in stool + anemia
Treatment: bendazole, pyrantel pamoate, iron

Question 7

Strongyloides Stercoralis

Answer 7

Three developmental options for rhabditiform larvae: direct: like hookworms except larvae in stool (no amp)
indirect: sexual reproduction in soil (environmental amplification)
Autoinfection: penetrate mucosa (lungs to intestines) (host amp)

transmission: penetration of skin or gut mucosa
Epidemiology: Domestic pets are reservoir hosts
Pathology: lung stuff, rash, worm load dependent
Immunity: inflammation
Diagnosis: larva in poop or spit, no eggs in stool, serology
Treatment: ivermectin and albendazole

Question 8

Trichinella spiralis

Answer 8

humans are dead end hosts. Infected animals serve as defifinitive and potential intermediate hosts, second host is required to complete the lifecycle

Transmission: eating undercooked meat (pork/wild game)
Pathology: asymptomatic, muscle pain, eyes, vomit, fever
Immunity: eosinophilia, humoral immunity
Treatment: bendazole, symptomatic (steroids)

Question 9

Tosocara canis (cati)

Answer 9

humans can be an accidental host from dog poop, or eating rabbits soil stage
Transmission: ingestion of embryonated eggs, no direct person to person soil stage
Pathology: neural stuff
Diagnosis: eyes
Treatment bendazoles