INTESTINAL NEMATODES Flashcards
most common cause of helminth infection in the world
Ascaris lumbricoides
most common cause of helminth infection in community
Enterobius vermicularis
third most common roundworm of humans
Trichuris trichiura
largest intestinal nematode
Ascaris lumbricoides
UNHOLY 3 / Most common soil transmitted helminths “Geohelminths” (HAT)
Hookworms (human)
Ascaris lumbricoides
Trichuris trichiura
parasitic females are parthenogenetic
Strongyloides stercoralis
females produce two types of eggs
Capillaria philippinensis
Causes interhnal autoinfection
Strongyloides stercoralis & Capillaria philippinensis
Common name of E. vermicularis
Pinworm
Seatworm
Door knob
Common name of T. trichiura
Whipworm
Common name of A. lumbricoides
Giant Intestinal Roundworm
Eelworm
Common name of
N. americanus
A. duodenale
A. ceylanicum
New World HW
Old world HW
Zoonotic HW
Common name of S. stercoralis
Threadworm
Common name of C. philippinensis
Pudoc worm
Diagnostic Stage is EMBRYONATED Egg
E. vermicularis
Diagnostic Stage is UNEMBRYONATED Egg
T. trichiura
Hookworms
C. philippinensis
Diagnostic Stage is FERTILIZED & UNEMBRYONATED Egg
A. lumbricoides
Diagnostic Stage is RHABDITIFORM Larvae
S. stercoralis
Ingestion of Embryonated Egg
E. vermicularis
T. trichiura
A. lumbricoides
Ingestion of infective larvae from raw fishes
C. philippinensis
Skin penetration by filariform larvae
S. tercoralis
N. Americanus
A. duodenale
Egg morphology:
50-60 um x 20-30 um; colorless;
D shaped / lopsided/ Planeconvex ;contain a fully developed larva
E. vermicularis
Egg morphology:
50-54 um x 23 um; yellow to brown; barrel, football, lemon, or Japanese lantern-shaped with ROUNDED HYALINE BIPOLAR PLUS
T. trichiura
Egg morphology:
45-70 x 35-50 µm; yellow brown;
round or ovoidal; THICK shell with 3
layers
Fertilized A. lumbricoides
Egg morphology:
88-94 x 39-44 µm; elongated; shell often very THIN and may be decorticated
UNfertilized A. lumbricoides
Egg morphology:
57-76 um x 35-47 um; oval or ellipsoidal with a thin colorless shell with grayish cells
Hookworms
Egg morphology:
50-58 um x 30-34 um; similar to those of
hookworms but are usually embryonated
S. stercoralis
Egg morphology:
36-45 um X 20 um; PEANUT SHAPED;
with flattened bipolar plugs and striated shell
C. philippinensis
Adult Morphology:
Whitish; morphologic features
include:
1. Cuticular alar expansion / cephalic alae / wing like extension
2. Esophageal bulb
E. vermicuralis
Adult Morphology:
Pinkish gray; WHIP-like with
slender anterior 2/3; esophagus
is lined by stichzytes
T, trichiura
Adult Morphology:
-Pink or white; superficially
resembles an EARTHWORM
-Mouth of male and female
adult has TRILOBATE LIPS
A. lumbricoides
Adult Morphology:
Characteristic of dental pattern:
- no teeth but with semilunar cutting plates
- 2 pairs of buccal teeth
- 1 pair of buccal teeth
- 3 pairs of buccal teeth
“ABDC” = 0123
- N. americanus
- A. duodenale
- A. braziliense
- A. caninum
Adult Morphology:
Short buccal cavity with
indistinct lips
S. stercoralis
Adult Morphology:
Thin filamentous anterior and a
slightly thicker posterior
Male has long sheathed
copulatory spicule
C. philippinensis
Morphology of Hookworm and Strongyloides Larvae
- 1st stage larva, feeding stage and with open mouth
- shorter and robust
- NOT INFECTIVE
- length of buccal cavity
- size of genital primordium
Rhabditiform larva
Morphology of Hookworm and Strongyloides Larvae
- 2nd stage larva, non-feeding stage and with closed mouth
- longer and slender
- INFECTIVE
- length of esophagus
- tail end
- presence or absence of sheath
Filariform larva
Morphology of Rhabditiform Larva of Hookworm
250um
- ____ buccal cavity (equal of body`s width)
- ___ genital primordium
- LONGER buccal cavity (equal of body`s width)
- SMALL / INCONSPICUOUS / INDISTINCT genital primordium
Morphology of of Rhabditiform Larva of S. stercoralis
225um
- ____ buccal cavity (halft of body`s width)
- ___ genital primordium
- SHORTER buccal cavity (halft of body`s width)
- LARGE/ CONSPICUOUS / DISTINCT genital primordium
Morphology of of Filariform Larva of S. stercoralis
- length of esophagus
- tail end
- presence or absence of sheath
- length of esophagus: Longer (550um)
- tail end: BIFID / Notched / Forked
- presence or absence of sheath: UNSHEATED
Morphology of of Filariform Larva of Hookworm
- length of esophagus
- tail end
- presence or absence of sheath
- length of esophagus: Shorter (700um)
- tail end: POINTED / Straight
- presence or absence of sheath: SHEATED
Enterobiasis _____ caused by female migration; insomnia and restlessness. Itchiness of anal region.
Pruritis Ani
Trichuriasis: Few or no symptoms; heavy infections may cause
Mild anemia due to mucosal bleeding and RECTAL PROLAPSE
Intestinal ascariasis; Ascaris pneumonitis or _____________________ – allergy and
peripheral eosinophilia; ectopic ascariasis
Loeffler`s syndrome
Characteristicof Capillariasis (mystery disease)
BORBORYGMI - gurgling stomach
Chinese lantern ova:_____
Japanese lantern ova:____
Chinese lantern ova: S. stercoralis
Japanese lantern ova: T. trichiura
Causes Pneumonitis due to lung migration in cycle “ASH”
A. lumbricodies
S. stercoralis
Hookworms (human)
Hookworm infection can cause: ___ that is MICROCYTIC, HYPOCHROMIC
Iron Deficiency Anemia
largest intestinal nematode
smallest intestinal nematode
largest intestinal nematode: A. lumbricoides
smallest intestinal nematode: S. stercoralis
Female roundworms that produce UNEMBRYONATED EGGS (external embryonation)
Oviparous
Roundworms that OVIPAROUS are
A. lumbricoides
Hookworms
Trichuris
Female roundworms that produce EMBRYONATED EGGS (internal embryonation)
Ovo-viviparous
Roundworms that OVO-VIVIPAROUS are
E. vermicularis
S. stercoralis
Female roundworms that do not lay eggs but instead produce LARVAE
Viviparous
Roundworms that VIVIPAROUS are
T. spiralis
Filariae
D. immitis
D. medinensis
Sensory organ with cephalic chemoreceptors present in all nematodes
Amphids
Sensory organ with caudal chemoreceptors & not present in ___
Phasmids
Aphasmidians (Trichuris, Trichinella & Capillaria)
