A person becomes infected by:
(1) ingesting eggs (fecal exposure from humans or rodents)
(2) swallowing an insect carrying eggs or larvae
Once infected a patient may undergo autoinfection, which can result in hyperinfection with a large worm burden.
The adult worm attaches to villi in the small intestine.
Clinical and laboratory findings:
(1) none (asymptomatic)
(2) anorexia
(3) abdominal pain
(4) diarrhea and/or mucus in stool
(5) headache
(6) dizziness
(7) eosinophilia
Severely immunocompromised patients are at risk for autoinfection or host invasion.
Eggs: thin walled, six-hooked oncosphere, polar filaments
Eggs:
(1) The eggs are infectious.
(2) The eggs are somewhat fragile and may be distorted in permanent stained smear or after fixation in polyvinyl alchol (PVA). The eggs are seen better in a concentrated wet mount or after fixation in formalin.
Adult worms and proglottids are rare in fecal specimens. They can be found in surgical specimens.
