Intestinal Nematodes - Cal Flashcards
AKA roundworms?
Intestinal nematodes
Nematodes dioecious or mono?
Dioecious
Cylindrical
Tapering at both ends
Unsegmented
Intestinal nematodes
Outer covering
Relatively impermeable
Protective
Shed during molting
Cuticle of intestinal nematode
Used for grasping the female
Bursa
Used for injection of spermatozoa
Spicules
Intestinal nematodes… operculated or na?
Nonoperculated
Giant intestinal roundworm?
Ascaris lumbricoides
Ascaris lumbricoides can cause?
Localized hemorrhage and edema
Appendicitis
Ascarid pneumonitis
Ectopic foci are sites other than the usual habitat in the body
Visceral larval migrans (Ascaris lumbricoides)
Ascaris lumbricoides mode of infection?
INgestion of mature eggs
Describe the Ascaris lumbricoides life cycle
Mature egg ingested, moves to intestine where it hatches. From there, it proceeds to heart then lungs/alveoli.
Then coughed up, swallowed where they mature/mate in intestine again.
Infective form of Ascaris lumbricoides?
Intermediate host?
Mature, embryonated egg
NO INTERMEDIATE HOST (swine can be a reservoir host)
Ascaris lumbricoides Ssx?
Most pts are asymptomatic.
Some develop pulmonary symptoms during lung migration phase.
Mild abdominal discomfort, dyspepsia, loss of appetite, and nausea may occur.
BUT
Depresses appetite and food intake by children, interferes with absorption of proteins, fats, lactose, vitamin A, and iodine.
Ascaris lumbricoides Diagnosis?
ID of passed adult worms… Examination of stool for eggs (decorticated ova)
Egg = brown cortication, with hyaline shell wall and yolk mass?
Ascaris lumbricoides
Persistent cough?
Ascaris lumbricoides
Soil transmissible helminth?
Ascaris lumbricoides
Most prevalent helminth infection?
Ascaris lumbricoides
WORLDWIDE
Larvae migrate to liver and lungs causing systemic responses, eosinophilic pneumonitis (Loeffler’s)
Ascaris lumbricoides
MOST concerned with intestinal obstruction
Pinworm or seatworm?
Enterobius vermicularis
Embryonated eggs ingested by human?
Enterobius vermicularis
Enterobius vermicularis mode of infection? Habitat? Reservoir host?
Ingestion
Large intestine/cecum
No reservoir host
Easily spread among school children
Enterobius vermicularis
Eggs infective within 6 hours and up to 20 days
Enterobius vermicularis
Specimen of choice is transparent adhesive tape specimen collection (“scotch-tape prep”) or pinworm paddle
Enterobius vermicularis
Enterobius vermicularis egg?
“D” shape
Hyaline
Triple layer shell wall