Medical Parasitology Lab Raed Z Ahmed Medical Parasitology Lab20122013 Prepared By Mr Raed Z Ahmed Protozoa in wet mount Saline wet mount In saline wet mount trophozoites and cyst of amoeba flagellates and ciliate may be seen ID: 208117
Download Presentation The PPT/PDF document "Staining of Parasites" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Staining of Parasites
Medical Parasitology Lab.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013
Prepared By:
Mr. Raed Z. AhmedSlide2
Protozoa in wet mount
Saline wet mount:In saline wet mount, trophozoites and cyst of amoeba, flagellates and ciliate may be seen.Cyst will appear as round or oval, refractile structure.
Trophozoite of amoeba may be round or irregular, but
trophozoite of flagellate
are usually
pyriform (elongated, pear- shaped).In freshly passed feces (the stool must not be more than 1hour old), motile trophozoites may be seen.Motility can be seen very helpful in identifying species, especially in case of flagellates.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide3
Organism may be detected with the low power (10x) objective, but a high power (40x) dry objective will be necessary to identify reliable the structure as a cyst or trophozoite.
With the high power dry objective, you can see motility, inclusions like erythrocytes and yeast in amoebic trophozoites, chromatoid bodies in amoebic cyst.Also, we can see the shape and structural detail (sucking discs, spiral grooves, or filaments) of flagellate trophozoites and cysts. Continue …….
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide4
Continue …….
However, it’s necessary to regulate carefully the microscope illumination so that the objects appear clearly.Too much or too little light will interfere with your observations.It’s also necessary to focus up and down to see all the layer of the specimen.Remember to examine the whole coverslip area in a systematic manner to reduce the chances of overlooking organisms.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide5
Iodine wet mount:Iodine wet mount are examined for amoebic and flagellate cysts
but not trophozoites because it’s killed by iodine.In the iodine wet mount, cytoplasm of the cyst will stain yellow or light brown, and nuclei will stain dark brown.
Cyst stained with iodine can be detected with 10x objective, but they are not refractile as in saline mount. 40x used to see the characteristics of the cysts.
In iodine stained cysts of
Entamoeba
, the arrangement of peripheral chromatin and the position of karyosome can be seen. If the peripheral chromatin isn’t present, the cyst is not an Entamoeba spp. These peripheral chromatin bodies stain light yellow.
Sometimes, young cysts contain glycogen, this stains dark brown with iodine.
Continue …….
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide6
Buffered Methylene Blue wet mount:If you see amoebic trophozoites, or structures that resemble trophozoites, you should prepare and examine BMB mount.After 5-10 minutes of staining, the trophozoite sometimes remain motile, but often curl up in BMB preparation. For that do not confuse curled trophozoites with cysts do not stain with BMB solution.
In the trophozoites, the nucleus and inclusion (RBC, yeast) will stain dark blue while the cytoplasm will stain light blue.
Continue …….
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide7
Occasionally, some trophozoite will not stain, so you should look for well- stained organisms.Look for peripheral nuclear granules (granules in membrane around the nucleus), if these are present, the trophozoite is an Entamoeba ssp
. and you must identify the species.Continue …….
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide8
Helminthes in wet mount
Eggs may be easily detected and identified in saline mounts.They should not be stained (stains may interfere with identification).Most eggs are large enough to be recognized with the low power (10x) objective, but a few small eggs will require a high power dry lens (40x) objective.In saline mounts, larvae may be present, and it’s easily recognized with 10x objective.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide9
In saline mounts, larvae of Strongyloides stercoralis may be seen, but Hookworm larvae are not usually present if the sample is fresh.
If the sample is old and contain Hookworm infection, then larvae may be present.SO, it may be necessary to distinguish between these two species.ACTIVITYFIND THE WAYS TO DIFFERENTIATE BETWEEN SPECIES IN OLD SAMPLES.
Continue …….
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide10
Liver Flukes
Fasciola
spp.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide11
Life cycle
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide12
Fasciola hepatica
Fasciola hepatica lives in the liver of man.Fasciola spp. have many stages:Oval eggs have miracidium,
cercaria
,
metcercaria
, larvae and adult stage.Intermediate host: Snail.Definitive host: Sheep.Infective stage (human): Metacercaria.Human infected by ingestion
metacercaria
from infected sheep.
Diagnosis:
Stool analysis to find
Fasciola
egg.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide13
Fasciola hepatica Egg
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide14
Fasciola hepatica Miracidium
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide15
Fasciola hepatica cercariae
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide16
Fasciola hepatica rediae
larvae
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide17
Fasciola hepatica Adult
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide18
Blood Flukes
Schistosoma spp.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide19
Life cycle
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide20
Schistosoma spp.
Also known as bilharzia, cause schistosomiasis or bilhariziasis. Schistosoma spp. have 4 stages:
Eggs,
miracidia
,
cercaria, and adult stage. Eggs are passed through urine or feces to fresh water, where larvae stage can infect a new host by penetrating the skin.Schistosoma eggs are non- operculated
but
spined
and have
miracidum
. Eggs hatch and release
miracidia
in water.
Miracidia
move in water looking for a special snail, and penetrate a snail tissue and developed to sporocyst.
Cercaria
releasaed
by snail into water and free swimming,
cercaria
has a bifid tail and penetrate intact skin
Cercaria lose tail during penetration and become
schitosomulae
, that circulate in the blood and migrate to portal blood of liver and mature into adult.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide21
Schistosoma spp. (cont
….)There are three medically important species:Schistosoma mansoni
, lives in the mesenteric
venules
of large
intestine, and cause intestinal bilharziasis.Schistosoma japonicum
,
lives in the mesenteric
venules
of small
intestine.
Schistosoma
haematobium
,
lives in the venous plexus of the urinary
bladder and cause
schistosomal
hematuria or urinary
bilhariziasis
.
S.
mansoni
and
S.
japonicum
are produce their eggs in stool, but
S.
haematobium
produce eggs in urine.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide22
Schistosoma spp. (cont
….)Intermediate host: snail.Definitive host: human.Cercaria is the infective stage but eggs are the diagnostic stage.
Diagnosis:Depends on finding the characteristic ova in feces or urine.
Three
species can be distinguished by the appearance of their eggs
under microscope:S. mansoni eggs have prominent lateral spine.
S.
japonicum
eggs have a very
small round
lateral spine.
S.
Haematobium
eggs
have
a terminal
spine.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide23
Snail for
Schistosoma spp.
Snails
Schistosome species
Bulinus spp.
S.haematobium
Biomphalaria spp.
S.mansoni
Oncomelania spp.
S.japonicum
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide24
Snail
Oncomelania
spp.
Biomphalaria
spp.
Bulinus spp.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide25
Schistosoma spp. Eggs
S.
japonicum
S. haematobium
S. mansoni
Lateral spine
Terminal spine
Rounded spine
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide26
Schistosoma miracidium
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide27
Schistosoma cercaria
Bifid tail
Oval head
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide28
Schistosoma adult male
Adult male short, thick and have
Gynaecophoric
canal
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide29
Schistosoma adult female
Adult female longer and thinner than adult male.
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013Slide30
Gynaecophoric canal
Raed Z. Ahmed, Medical Parasitology Lab.,2012-2013