GI nematodes Flashcards
What are nematodes
- roundworms that are non-segmented, have separate sexes and have a complete digestion system
- need two to reproduce
what are cestodes
-tapeworms that are segmented, hermaphroditic (only need on to reproduce) and absorb nutrients instead of eating them
tremodes
non-segmented, leaf shaped, hermaphrodidic with primitive (one opening) gut
where are nematodes mostly found in the US and why
in the south east because like warm, moist weather
can females still produce eggs without a male (for nematodes)
yes but they are not infectious because they are not fertilized
what does it mean when we say that adult nematodes do not replicate in man?
- means that the number of worms does not increase unless you ingest more worms
- worms reproduce and are shed in stool
what is a telling lab finding for nematode infection?
- eosinophilia
- when GI nematodes pass thru other tissues (lungs, skin) during development cause eosinophilia that are meant to fight back
Enterobius vermicularis (pinworm)
- egg shape
- how do they infect
- oval with one flat side
- eggs are ingested and eggs hatch in small intestine and larvae move to large intestine and penetrates the mucosa to develop
- larvae mature in 2-6 wks and adults lie in the lumen of the cecum
- female crawls at night (lower body temp) to perianal region to lay eggs outside the anus
transmission of enterobius vermicularis (pinworm)
symptoms
diagnosis
prevention/control
- oral- fecal route- ingest eggs
- symptoms- asymptomatic, itchiness
- scotch tape test -eggs in perianal region
- prevention-good hygiene and housekeeping
- control- anti-helminthic compounds (mebendazole, pyrantel pamoate)- one dose and another 2 wks later
whipworm-Trichuris trichiura
shape
type
pathogenesis
- shape- barrel shaped and plugs on both sides
- type -geohelminths- need soil to grow
- infected individual deficates into spoil with eggs in it, EGGS MATURE IN SOIL FOR 3 WEEKS, then ingested by humans (produce), eggs hatch in small intestine releasing larvae, larvae penetrates and develops in mucosa of large intestine and adults found in cecum, females lay eggs after 3 mo.
symptoms of trichurias trichuria
- trichurius trichuria (sounds like bicurious =whip worm)
- asymptomatic
- if severe- causes bloody, mucus-filled diarrhea, frequent stool and rectal prolapse (from straining to defecate), growth retardation and anemia in kids
diagnosis and prevention of trichurias trichuria?
- ID eggs in stool
- proper sanitation and personal hygiene
Ascariasis
pathogenesis
- caused by ascaris lumbricoides = largest nematode (from your ass you cry b/c nematode so big)
- infected person defecates eggs into spoil and eggs develop for two weeks and are ingested
- eggs hatch and larvae get into circulation
- go thru GI to liver to the lungs -cough and swallow sputum and sent back to GI
- adult larvae develop in the lumen of the small intestine
- females lay eggs that are defecated (whole process- 1 month)
what would you expect to see in the labs for Ascariasis?
-increase eosinophils trying to kill off the ascaris lumbricoides
if obtaining the sputum sample of someone with ascariasis, what would you see in it?
- eosinophils and larvae
what should be known in terms of reservoirs for ascaris lumbricoides?
- humans are the only reservoir
- pigs have ascarid but they rarely infect humans
symptoms of ascariasis?
- ranges from asymptomatic to intestinal and pulmonary disease
- intestinal: ab pain, indigestion, vomiting and diarrhea
- heavy infections can cause physical obstruction of small intestine (since adults live there)
- kids= nutritional deficiency, growth retardation
*Pulmonary: mild cough and pneumonitis (inflammation of alveoli), asthma attack (allergies to larvae)
Diagnosis and control/prevention of ascariasis
diagnosis- eggs in stool, larvae or eosinophils in sputum
prevention- hygiene and sanitation
what are two species of hookworms and what’s their pathogenesis?
- necator americanus (in southeast USA)
- ancyclostoma duodenale (rest of world)
- eggs in soil hatch and soil wait around for something to brush up against it and when they do, they penetrate the skin via digestive enzymes that allow it to enter the blood stream and reach the lungs, coughed and swallowed allowing it to reach small intestine and mature and reproduce there
what’s important to know about reservoirs for hookworms?
-no animal reservoir for human hookworms BUT
dog hookworms can infect humans and give cutaneous larval migraines
symptoms of hookworm infection
necator americanus or ancyclostoma duodenale
-anemia and iron deficiency due to blood loss from feeding
-infection severe enough to cause fatigue, dyspnea, pale sclera and heart murmurs and KOILONYCHIAS (SPOON SHAPED NAILS)
-moderate dermatitis
-pneumonia and eosinophilia
=ANCYLOSTOMA IS MORE PATHOGENIC THAN NECTOR AMERICANUS
diagnosis and prevention of hookworm disease (necator aericanus and ancyclostoma duodenale)
diagnosis- eggs in stool- distinguishing between the two requires examination of adult worms or larvae
prevention- sanitation and SHOES
strogloidiasis
caused by-
normal pathogenesis
- caused by strongyloides stercoralis (the strong coral the rest) =smallest nematode
- ONLY ONE where people defecate LARVAE
- larvae grow in soil, make eggs, hatch and larvae enter circulation and go up thru lungs, coughed and swallowed in sputum and then infects GI
whats important to note about strongloides stercoralis
- it can survive without humans
- it also has a hyperinfectious state where it can go from the GI and penetrate it and reenter the bloodstream and re-initiate the infection
- humans shed larvae in their feces and not eggs
symptoms of strongloidiasis
- non-specific- epigastric pain, tenderness, bloating and heartburn
- pulmonary stage- provoke pulmonary inflammation
- hyperinfection causes diarrhea, more pulmonary symptoms
- disseminated= migration of larvae not only to lungs and GI but to CNS, peritoneum, liver and kidney (immunosuppressed peeps)
diagnosis and prevention of strongliodiasis
- detection of larvae in stool
- sanitation and hygiene with SHOES
know your eggs! lemon/barrel shaped - flat on one side- lumpy bumpy- boring-
lemon/barrel shaped - tichuris trichuria (whipworm)
flat on one side- enerobias vermicularis (pinworm)
lumpy bumpy- ascaris lumbrioids
boring- hookworm
