NEMATODES (ROUNDWORMS) Flashcards
Cylindrical, unsegmented, bilaterally symmetrical bodies
nematodes
produce unembryonated eggs (undergo external embryonation/outside uterus)
ociparous
oviparous nematodes
A. lumbricoides, T. trichiura, Hookworms
produce embryonated eggs (internal embryonation)
ovo-viviparous
examples of ovoviviparous nematodes
E. vermicularis, S. stercoralis
do not lay eggs; produce larvae
T. spiralis, Filarial worms, D. medinensis, D, immitis (Dog filaria)
cephalic chemoreceptors present in all nematodes
amphids
caudal chemoreceptors
phasmids
phasmids are absent in ____
Trichiuris, Trichinella, Capillaria spp (aphasmideans)
nematodes in the small intestine
CASH
- C. philippinensis
- A. lumbricoides
- S. stercoralis
- Hookworms
nematodes in the large intestine
E. vermicularis, T. trichiura
Extraintestinal nematode
T. spiralis, Filarials, D. medinensis, agents of larva migrans
produces significant clinical manifestations
T. spiralis
most common cause of helminth infection in the world
E. vermicularis
third most common roundworm of humans
T. trichiura
largest intestinal nematode
A. lumbricoides
blood sucking nematodes
hookworms
parasitic females are parthenogenetic
S. stercoralis
females produce two types of eggs
C. philippinensis
easily transmitted hand to mouth; eggs are already embryonated
E. vermicularis
Unholy three
ASH
- A. lumbricoides
- S. stercoralis
- Hookworms
most common soil transmitted helminths/geohelminths
ASH
- A. lumbricoides
- S. stercoralis
- Hookworms
may cause internal autoinfection
- S. stercoralis
- C. philippinensis
infective stage of S. stercoralis
filariform larvae
diagnostic stage
rhabditiform larvae
true or false
dogs may also serve as definitive host of S. stercoralis
true
diagnostic stage of C. philippinensis
unembryonated, thick shelled eggs
infective stage C. philippinensis
infective larvae
MOT of C. philippinensis
ingestion of raw or undercooked infected fish
2 types of eggs of C. philippinensis
- unembryonated eggs passed in feces
- embryonated eggs lacking shells (hatch inside definitive host)
common name of E. vermicularis
Pinworm/seatworm
common name of T. trichiura
Whipworm
common name of A. lumbricoides
Giant intestinal roundworm
common name of N. americanus
New World Hookworm
common name of A. duodenale
Old World Hookworm
common name of A. ceylanicum
Zoonotic Hookworm
common name of S. stercoralis
Threadworm
common name of C. philippinensis
Pudoc Worm
diagnostic stage of E. vermicularis
embryonated eggs (immediately infective)
diagnostic stage of T. trichiura
unembryonated eggs
diagnostic stage of A. lumbricoides
fertilized and unfertilized eggs
diagnostic stage of N. americanus, A. duodenale, A. ceylanicum
unembryonated eggs
diagnostic stage of S. stercoralis
Rhabditirform larvae
diagnostic stage of C. philippinensis
unembryonated eggs
MOT of E. vermicularis
hand to mouth or inhalation
MOT of T. trichiura
ingestion of embryonated eggs from contaminated sources
MOT of:
N. americanus
A. duodenale
A. ceylanicum
Strongyloides stercoralis
skin penetration by filariform larvae
MOT of C. philippinensis
ingestion of infective larvae from fish
true or false
eggs of E. vermicularis are immediately infective
true
larvae does not undergo lung migration
T. trichiura
larvae undergo lung migration
A. lumbricoides
N. americanus
A. duodenale
A. ceylanicum
Strongyloides stercoralis
intermediate host of C. philippinensis
Fish
causes true clinical manifestation in man when infected
A. ceylanicum
almost never found in feces
S. stercoralis
test for S. stercoralis
entero test
D-shaped, lopsided, planoconvex
E. vermicularis
50-60 um x 20-30 um; colorless; contain a fully
developed larva
E. vermicularis
recovered in the swabs of E. vermicularis
Female adults
barrel, football, lemon, or Japanese lantern-shaped
with rounded bipolar plugs
T. trichiura
50-54 um x 23 um; yellow to brown
T. trichiura
esophagus of adult T. trichiura is lined by _______
Stichocytes
makes rigidity for colon attachment of T. trichiura adult
stichocytes
45-70 x 35-50 µm; yellow brown; round or ovoidal;
thick shell with 3 layers
fertilized A. lumbricoides
3 layers of Fertilized A. lumbricoides
- mamillary coat/cortex
- glycogen layer
- lipoidal vitaline membrane
true or false
fertilized A. lumbricoides contains single germ cell
true
true or false
unembryonated A. lumbricoides also contains germ cell
false; it does not contain
88-94 x 39-44 µm; elongated;
shell often very thin and may be decorticated
unfertilized A. lumbricoides
Mouth of male and female
adult A. lumbricoides has _______
trilobate lips
eggs are indistinguishable from each other
Hookworm and S. stercoralis
eggs contain egg packets or grayish germ cell (4-8)
hookworms and S. stercoralis
dental pattern of adult N. americanus
pair of semilunar cutting plates
dental pattern of adult A. duodenale
2 pairs of teeth
Short buccal cavity with
indistinct lips (parthenogenetic)
S. stercoralis
peanut shaped
C. philippinensis
36-45 um X 20 um;
with flattened bipolar plugs and striated shell
C. philippinensis
Thin filamentous anterior and a slightly thicker posterior
Male has long sheathed
copulatory spicule
C. philippinensis
sheathed filariform larva
hookworm
unsheathed filariform larva
S. stercoralis
buccal cavity is the same length as the body
Hookworms
buccal cavity is ~1/2 of the body’s width
S. stercoralis
genital primordium of hookworm
small and inconspicuous
genital primordium of S. stercoralis
large and conspicuous
tail of hookworm
pointed
tail of S. stercoralis
forked/notched/bifid
esophagus
hookworm: short
S. stercoralis: long
pruritis ani caused by female migration; insomnia and restlessness
Enterobiasis
intense itchiness in anal/perianal area
pruritis ani
heavy infection of T. trichiura may cause
mild anemia and rectal prolapse
may cause Loeffler’s syndrome
Ascariasis
Intestinal ascariasis; Ascaris pneumonitis or Loeffler’s syndrome– allergy and
peripheral eosinophilia; ectopic ascariasis
Ascariasis
bollus of intestine (may obstruct airway, bile duct)
Ascariasis
cutaneous hookworm infection
ground itch
cutaneous Strongyloidiasis
larva currens
pulmonary hookworm infection
Loeffler’s syndrome
intestinal hookworm infection may cause
GI blood loss
anemia in hookworm infection
IDA (microcytic and hypochromic)
intestinal strongyloidiasis
diarrhea and malabsorption
Abdominal pain, chronic diarrhea and peculiar abdominal gurgling sound
Capillariasis
abdominal gurgling sound
borborygmus
mystery disease; discovered in Barrio Pudoc in the Philippines
Capillariasis (C.philippinensis)