midterms Flashcards
(118 cards)
refer to intestinal nematodes that are
transmitted through contaminated soil,
Soil-transmitted Helminths (STHs),
soil transmitted helminths exampless
giant
intestinal round worm of man Ascaris lumibricoides, the
human whipworm Trichuris trichuria, and the human
hookworms Ancylostoma duodenale and Necator americanus.
the giant intestinal roundworm”
Ascaris lumbricoides
morphology of ascaris lumbricides
- resembles an earthworm.
- Appearing light brown or pinkish when freshly expelled from the
intestine but gradually turns white.
male a. lumbricoides
15 to 30 cm in length and 3 to 4 mm in diameter. It has a ventrally curled
tail with protruding spicules.
female a. lumbricoides
- 20 to 35 cm in length and 5 mm in diameter and has a straight pointed
posterior end. - Capable of liberating fertilized and unfertilized eggs, which are passed
out with the feces of the human host.
a lumbricoides morphology
Both sexes have tapering ends with the anterior end being thinner than
the posterior. Fine striations are visible in the cuticle. The mouth at the
anterior end has three lips, one dorsally and two ventrally located.
a. lumbricoides egg
Longer and narrower, measuring
60 to 100 um by 40 to 60 um. It
has a thinner shell with more
variable mamillated layer.
Inside is a mass of refractile
granules .
a. lumbricoides egg
Round or oval, 45 to 70 μm in length and 35 to 45 um in width, and golden
brown due to bile.
Contains a zygote that is enclosed in a thick chitin shell with an external
albuminous mamillated covering (corticated eggs). In some cases, the
outermost mamillated layer is absent (decorticated eggs).
transmisison o fa lumbri
fecal-oral, Ingestion of infective embryonated ova occur in several ways:eating, f=drinking and ingestoin
diagnosis of a lumbricoides
kato katz, direct fecal smear (DFS) and formalin-ether
concentration technique (FECT).
light, moderate and heavy infection in a. lumbricoides
Light Infection
1,000 to 4,999
Moderate
Infection
5,000 to
49,000
Heavy
Infection
≥ 50,000
commonly used microscopy-based examination of stool samples for
the presence of ova includes d
irect fecal smear (DFS) and formalin-ether
concentration technique (FECT).
treatment of a lumbricoides
benzimidazoles mebendazole (MBZ) and
albendazole (ALB).
The dose and duration of treatment depends on STH species with A.
lumbricoides generally gets treated
for 1-3 days.
a lumbricoides can cause
In cases of intestinal obstruction and rectal
prolapse,
“ the human whipworm”
Trichuris trichuria
morphology of trichuris trichuria
The adult worm resembles a whip, the anterior three fifth is very thin and
hair-like consists of a long esophagus.
The thicker posterior portion contains intestine and sex organs.
They attach to the host through their slender anterior end.
Females are larger than the male approximately 30 to 45 mm.
egg of tt
Ellipsoidal to barrel-shaped, measuring 50 to 70 um in length and 25 um in
width, and has two distinct colorless polar plugs.
It has a double shell with a bi stained outer layer.
treatment of trichuristrichuira
benzimidazoles mebendazole (MBZ) and
albendazole (ALB).generally gets treated for 1-3 days.
infection rate of trichuris trchiura
Light Infection
1 to 999
Moderate
Infection
1,000 to 9,999
Heavy
Infection
≥ 10,000
hook worms
Ancylostoma duodenale, Necator americanus
a. duodunale morphology
Often reddish color when passed due to ingested blood. The mouth is on
the dorsal surface with two hook like teeth on the top and two triangular
cutting plates on the bottom.
n. americanus characterist8ics
Slightly smaller, the mouth has no teeth but with four chitinous cutting
plates, two each on the ventral and dorsal surfaces.