PARA 4 Flashcards
Giardia lamblia habitat
duodenum and upper jujenum
giardia lamblia distribution
-global distribution
-endemic in tropics and sub tropics, where sanitation is poor
-travelers develop traveler’s diarrhea
what characteristics does giardia lamblia trophozoite have
- pyriform, rounded anterior, pointed posterior
- 15upm x 9upm
- dorsally convex, ventrally concave ( sucking discs for attachment to intestinal mucosa)
- bilaterally symmetrical
- 2 nuclei, 4 pairs of flagella, 1 axostyles along the midline, and 2 parabasal/median bodies
what are the characteristics of a giardia lamblia cyst
- infective form
- oval
- 12upm x8upm
- immature cyst: 2 nuclei
-mature cyst: 4 nuclei - axostyle lies diagonally
- remnants of flagella may be found in the cyst
describe the life cycle of the giardia lamblia
(1) Cysts are passed out in stool of an
infected human. (2) Infective cysts are
ingested. (3) The cyst excysts to release
trophozoite in the small intestine. (4) The
trophozoites multiply by binary fission. (5)
The trophozoite encysts to become cyst
which is passed out in the stool.
what kind of asexual reproduction happens in a giardia lamblia life cycle after the cyst excysts
binary fission
true or false: giardia lamblia needs 2 hosts, intermediate and primary host, in its life cycle.
false, it only needs 1 host
other word for malabsorption
steatorrhea
what are the characteristics of the stool when infected with giardia lamblia ?
stool contains excess mucus and fat
incubation period of giardia lamblia
about 2 weeks
how does giardia lamblia attatch itself
it does not invade tissue. it only attaches to intestinal epithelium through the sucking disc, causing shortening and stunting of the villi.
though usually asymptomatic, what are the possible symptoms of the patients when infected with giardia lamblia
diarrhea, fat malabsorption, dull epigastric paint, and flatulence
diagnosis methods of giardia lamblia
- microscopic examination
- enterotest ( stringtest)
- molecular diagnosing
describe microscopic examination for gardia lamblia
- detects cyst and trophozoites in stool by direct saline/iodine wet preparations and use of concentration technique like formal ether.
- asymptomatic carriers, only cysts are seen
- fixed stool smear can be stained with trichrome to identify cyst and trophozoites
describe enterotest ( string test) giardia lamblia
- duodenal specimen to detect parasites
- gelatin capsule attached to a thread
- capsule is swallowed, gets dissolved in the intestine to release the thread which is kept there for 4-6 to take duodenal fluid
- thread is then withdrawn to be shaken in saline to release trophozoites and to be detected with a microscopically
- research in upper intestinal parasites such as Stronglyoides stercoralis
describe molecular diagnosis in giardia lamblia
- PCR on stool specimen
treatment for giardia lamblia
- metronidazole (250mg 3 times daily for 5 days) or tinidazole
- paromomycin can be given to symptomatic pregnant woman.
trichimonas vaginalis distribution
worldwide
trichimonas vaginalis habitat
female: vagina and cervix
male: anterior urethra
trichomonas vaginalis morphology
- only trophozoite stage
trichimonas vaginalis trophozoite shape
- pear shaped or ovoid
- length: 10-30 upm width: 5-10upm with a short undulating membrane reaching up to the middle of the body
- 4 anterior flagella, a 5th running along the outer margin of the undulating membrane
- prominent axostyle runs through the length of the body and project posteriorly.
life cycle of trichomonas vaginalis
Trophozoites live in the vagina
and cervix and may also be found
in Bartholin’s glands, urethra and
urinary bladder in females. In
males, it occurs mainly in the
anterior urethra, but may also be
found in the prostate.
(2) Trophozoites multiply by
longitudinal binary fission.
(3) Trophozoites in vagina or
orifice of urethra can be found in
the vaginal and prostatic
secretions and urine
